Patent Application
20230062568
The contents of the text file submitted electronically herewith are incorporated herein by reference in their entirety: A computer readable format copy of the Sequence Listing filename: PIVO_018_00US_SeqList_ST25.txt, date created, Jan. 12, 2020, file size 632 kilobytes.
By 2050 the United Nations' Food and Agriculture Organization projects that total food production must increase by 70% to meet the needs of a growing population, a challenge that is exacerbated by numerous factors, including: diminishing freshwater resources, increasing competition for arable land, rising energy prices, increasing input costs, and the likely need for crops to adapt to the pressures of a drier, hotter, and more extreme global climate.
Current agricultural practices are not well equipped to meet this growing demand for food production, while simultaneously balancing the environmental impacts that result from increased agricultural intensity.
One of the major agricultural inputs needed to satisfy global food demand is nitrogen fertilizer. However, the current industrial standard utilized to produce nitrogen fertilizer, is an artificial nitrogen fixation method called the Haber-Bosch process, which converts atmospheric nitrogen (N2) to ammonia (NH3) by a reaction with hydrogen (H2) using a metal catalyst under high temperatures and pressures. This process is resource intensive and deleterious to the environment.
In contrast to the synthetic Haber-Bosch process, certain biological systems have evolved to fix atmospheric nitrogen. These systems utilize an enzyme called nitrogenase that catalyzes the reaction between N2 and H2, and results in nitrogen fixation. For example, rhizobia are diazotrophic bacteria that fix nitrogen after becoming established inside root nodules of legumes. An important goal of nitrogen fixation research is the extension of this phenotype to non-leguminous plants, particularly to important agronomic grasses such as wheat, rice, and corn. However, despite the significant progress made in understanding the development of the nitrogen-fixing symbiosis between rhizobia and legumes, the path to use that knowledge to induce nitrogen-fixing nodules on non-leguminous crops is still not clear.
Consequently, the vast majority of modern row crop agriculture utilizes nitrogen fertilizer that is produced via the resource intensive and environmentally deleterious Haber-Bosch process. For instance, the USDA indicates that the average U.S. corn farmer typically applies between 130 and 200 lb. of nitrogen per acre (146 to 224 kg/ha). This nitrogen is not only produced in a resource intensive synthetic process, but is applied by heavy machinery crossing/impacting the field's soil, burning petroleum, and requiring hours of human labor.
Furthermore, the nitrogen fertilizer produced by the industrial Haber-Bosch process is not well utilized by the target crop. Rain, runoff, heat, volatilization, and the soil microbiome degrade the applied chemical fertilizer. This equates to not only wasted money, but also adds to increased pollution instead of harvested yield. To this end, the United Nations has calculated that nearly 80% of fertilizer is lost before a crop can utilize it. Consequently, modern agricultural fertilizer production and delivery is not only deleterious to the environment, but it is extremely inefficient.
In order to meet the world's growing food supply needs—while also balancing resource utilization and providing minimal impacts upon environmental systems—a better approach to nitrogen fixation and delivery to plants is urgently needed. While microbial-based nitrogen fixation provides a promising avenue for supplying the nitrogen needs of various crops, existing solutions are inadequate to provide the full extent of nitrogen required throughout the course of a crop's life.
There is a long-felt and unmet need for viable natural alternatives to synthetic fertilizers that can provide nitrogen to plants.
The present disclosure provides a synthetic composition of microbes functionally optimized for nitrogen fixation and targeted delivery to a host plant, comprising: a consortium of at least two microbial species that differ in functional attributes along at least one of the following dimensions:
a) nutrient utilization;
b) temporal occupation;
c) oxygen adaptability; and
d) spatial occupation.
In some embodiments, the consortium comprises at least two microbial species selected from the group consisting of Klebsiellavariicola, Kosakonia sacchari, Paraburkholderia tropica, Herbaspirillum seropedicae, Herbaspirillum aquaticum, and Paenibacillus polymyxa.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of nutrient utilization.
In some embodiments, the difference in nutrient utilization comprises a difference in nutrient utilization in growth and/or nutrient utilization assays in one or more media comprising at least two different nutrient sources.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of nutrient utilization, and a nutrient they utilize differently is a carbon source selected from a simple carbohydrate, complex carbohydrate, organic acid, amino acid, and carboxylic acid.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of nutrient utilization, and a nutrient they utilize differently is a nitrogen source selected from an amino acid, amine, amide, and peptide.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of nutrient utilization, and they differ in the utilization of nutrients available in a plant rhizosphere, surface plant tissue region, and/or endophytic plant tissue region.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of nutrient utilization, and they differ in the utilization of nutrients available in the corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of nutrient utilization, and they differ in the utilization of a simple carbohydrate, complex carbohydrate, organic acid, or carboxylic acid and/or an amino acid, amine, amide, or peptide available in the corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of nutrient utilization, and the different nutrient utilization is such that the at least two microbial species could co-exist non-competitively in a plant rhizosphere, surface plant tissue region, and/or endophytic plant tissue region.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of nutrient utilization, and the different nutrient utilization is such that the at least two microbial species could co-exist non-competitively in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of temporal occupation.
In some embodiments, the difference in temporal occupation comprises a difference in nitrogen fixation at different time points in a plant growing cycle.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of temporal occupation, and the peak nitrogen fixation time period of the at least two microbial species differs by at least 2 weeks, at least 3 weeks, at least 4 weeks, at least 5 weeks, at least 6 weeks, at least 7 weeks, at least 8 weeks, at least 9 weeks, at least 10 weeks, at least 11 weeks, or at least 12 weeks in the average growing cycle of a given plant.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of temporal occupation, and the peak nitrogen fixation time period of the at least two microbial species differs by at least 2 weeks in the average growing cycle of a given plant.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of temporal occupation, and the peak nitrogen fixation time period of the at least two microbial species differs by at least 1 month, at least 2 months, at least 3 months, at least 4 months, at least 5 months, at least 6 months, at least 7 months, at least 8 months, at least 9 months, or at least 10 months in the average growing cycle of a given plant.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of temporal occupation, and the peak nitrogen fixation time period of the at least two microbial species differs by at least 1 month in the average growing cycle of a given plant.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of temporal occupation, and the different temporal occupation is such that the at least two microbial species could non-competitively fix nitrogen for a given plant at different time periods of the plant's growing cycle.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of temporal occupation in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of temporal occupation in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn, and the peak nitrogen fixation time period of the at least two microbial species differs by at least one stage in the growing cycle of corn.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of temporal occupation in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn, and the peak nitrogen fixation time periods of the at least two microbial species occurs during a different stage, or series of two or more stages, of the corn growing cycle selected from VE, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13, V14, V15, V16, VT, R1, R2, R3, R4, R5, and R6.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of temporal occupation in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn, and the peak nitrogen fixation time periods of the at least two microbial species occur during different periods of the corn growing cycle selected from V4-V6, V6-V10, and V10-V12.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of temporal occupation in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn, and the different temporal occupation is such that the at least two microbial species could non-competitively fix nitrogen at different time periods of the corn growing cycle.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of oxygen adaptability.
In some embodiments, the difference in terms of oxygen adaptability comprises a difference in nitrogen fixation under different oxygenation conditions.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of oxygen adaptability, and the at least two microbial species exhibit optimal nitrogen fixation under different conditions, or different combinations of conditions, selected from hypoxic, anaerobic, aerobic, and microaerobic conditions.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of spatial occupation.
In some embodiments, the difference in spatial occupation comprises a difference in colonization of the species in the rhizosphere, surface plant tissue region, and/or endophytic plant tissue region of a given plant.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of spatial occupation, such that the plurality of microbes of one species comprised by the consortium occupies a different location on the plant than a plurality of microbes of another species.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of spatial occupation of one or more of the endorhizosphere, the rhizoplane, and the ectorhizosphere.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of spatial occupation of the endorhizosphere.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of spatial occupation of the rhizoplane.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of spatial occupation of the ectorhizosphere.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of spatial occupation of one or more of the root junctions, zone of elongation, root cap, root mucilage, root hairs, root surface, and plant stems of a given plant.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of spatial occupation of one or more of the root junctions, zone of elongation, root cap, root mucilage, root hairs, root surface, and stems of corn.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of spatial occupation in the corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of spatial occupation, and the different spatial occupation is such that the at least two microbial species could co-exist non-competitively in a plant's rhizosphere, surface plant tissue region, and/or endophytic plant tissue region.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of spatial occupation, and the different spatial occupation is such that the at least two microbial species could co-exist non-competitively in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
In another aspect, the present disclosure provides a composition, comprising: a consortium of at least two microbial species selected from the group consisting of Klebsiella variicola, Kosakonia sacchari, Paraburkholderia tropica, Herbaspirillum seropedicae, Herbaspirillum aquaticum, and Paenibacillus polymyxa.
In some embodiments, at least one of the microbial species comprises heterologous genetic material, and the microbial species has improved nitrogen fixation relative to the microbial species without the heterologous genetic material.
In some embodiments, at least one of the microbial species lacks genetic material, and the microbial species lacking the genetic material has improved nitrogen fixation relative to the microbial species comprising the genetic material.
In some embodiments, at least one microbial species is genetically engineered to fix atmospheric nitrogen and provide such to a host plant.
In some embodiments, at least one microbial species is a remodeled microbe.
In some embodiments, at least one microbial species is a transgenic microbial species.
In some embodiments, at least one microbial species comprises a non-intergeneric genomic modification.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species capable of fixing atmospheric nitrogen in the presence of exogenous nitrogen.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into at least one gene, or non-coding polynucleotide, of the nitrogen fixation or assimilation genetic regulatory network.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising an introduced control sequence operably linked to at least one gene of the nitrogen fixation or assimilation genetic regulatory network.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising a heterologous promoter operably linked to at least one gene of the nitrogen fixation or assimilation genetic regulatory network.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into a gene selected from the group consisting of: nifA, nifL, ntrB, ntrC, polynucleotide encoding glutamine synthetase, glnA, glnB, glnK, drat, amtB, polynucleotide encoding glutaminase, glnD, glnE, nifJ, nifH, nifD, nifK, nifY, nifE, nifN, nifU, nifS, nifV, nifW, nifZ, nifM, nifF, nifB, nifQ, a gene associated with biosynthesis of a nitrogenase enzyme, and combinations thereof.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into at least one gene, or non-coding polynucleotide, of the nitrogen fixation or assimilation genetic regulatory network that results in one or more of: increased expression or activity of NifA or glutaminase; decreased expression or activity of NifL, NtrB, glutamine synthetase, GlnB, GlnK, DraT, AmtB; decreased adenylyl-removing activity of GlnE; or decreased uridylyl-removing activity of GlnD.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising a mutated nifL gene that has been altered to comprise a heterologous promoter inserted into said nifL gene.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising a mutated glnE gene that results in a truncated GlnE protein lacking an adenylyl-removing (AR) domain.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising a mutated amtB gene that results in the lack of expression of said amtB gene.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one of: a mutated nifL gene that has been altered to comprise a heterologous promoter inserted into said nifL gene; a mutated glnE gene that results in a truncated GlnE protein lacking an adenylyl-removing (AR) domain; a mutated amtB gene that results in the lack of expression of said amtB gene; a mutated glnD gene that results in a truncated GlnD protein lacking a uridyl-transferase domain or lack of expression of said glnD gene, and combinations thereof.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into genes involved in a pathway selected from the group consisting of: exopolysaccharide production, endo-polygalaturonase production, trehalose production, and glutamine conversion.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into genes selected from the group consisting of: bcsii, bcsiii, yjbE, fhaB, pehA, otsB, treZ, glsA2, and combinations thereof.
In some embodiments, at least one microbial species is a non-intergeneric remodeled bacterium selected from: Paenibacillus polymyxa, Paraburkholderia tropica, Herbaspirillum aquaticum, Metakosakonia intestini, Rahnella aquatilis, Klebsiella variicola, Achromobacter spiritinus, Achromobacter marplatensis, Microbacterium murale, Kluyvera intermedia, Kosakonia pseudosacchari, Enterobacter sp., Azospirillum lipoferum, Kosakonia sacchari, and combinations thereof.
In some embodiments, at least one microbial species is a non-intergeneric remodeled bacterium selected from: a bacteria deposited as ATCC PTA-126575, a bacteria deposited as ATCC PTA-126576, a bacteria deposited as ATCC PTA-126577, a bacteria deposited as ATCC PTA-126578, a bacteria deposited as ATCC PTA-126579, a bacteria deposited as ATCC PTA-126580, a bacteria deposited as ATCC PTA-126584, a bacteria deposited as ATCC PTA-126586, a bacteria deposited as ATCC PTA-126587, a bacteria deposited as ATCC PTA-126588, a bacteria deposited as NCMA 201701002, a bacteria deposited as NCMA 201708004, a bacteria deposited as NCMA 201708003, a bacteria deposited as NCMA 201708002, a bacteria deposited as NCMA 201712001, a bacteria deposited as NCMA 201712002, a bacteria deposited as PTA-126740, a bacteria deposited as PTA-126743, and combinations thereof.
In some embodiments, at least one microbial species is a non-intergeneric remodeled bacterium comprising a nucleic acid sequence that shares at least about 90%, 95%, or 99% sequence identity to a nucleic acid sequence selected from SEQ ID NOs: 177-260, 296-303, and 458-469.
In some embodiments, at least one microbial species is a non-intergeneric remodeled bacterium comprising a nucleic acid sequence selected from SEQ ID NOs: 177-260, 296-303, and 458-469.
The present disclosure also provides a method of using a composition according to any one of the foregoing embodiments.
In some embodiments, the method is for improving the nitrogen delivery to a plant.
In some embodiments, the method is for improving the quantity of nitrogen delivered to a plant.
In some embodiments, the method is for improving the quantity of nitrogen delivered to a plant at a specific time during the plant's growing cycle.
In some embodiments, the method is for improving the overall quantity of nitrogen delivered to a plant over the entire course of the plant's growing cycle.
In some embodiments, the method comprises applying the composition to a plant.
In some embodiments, the method comprises applying the composition to a plant by applying the composition to the plant seeds prior to planting.
In some embodiments, the method comprises applying the composition to a plant by applying the composition to the plant seeds or the plant itself during or after planting.
In some embodiments, the method comprises applying the composition to a plant, and the method results in improved plant yield compared to a plant not comprising the composition.
In some embodiments, the method comprises applying the composition to a plant, and the method results in improved plant yield compared to a plant not comprising a nitrogenous fertilizer.
In some embodiments, the method comprises applying the composition to a plant, and the method results in improved plant yield compared to a plant not comprising the composition.
In some embodiments, the method comprises applying the composition to a plant, and the method reduces the need for a synthetic source of nitrogenous fertilizer.
In some embodiments, the method comprises applying the composition to a plant, and the plant is corn.
In another aspect, the present disclosure provides a method of creating a synthetic composition of microbes functionally optimized for nitrogen fixation and targeted delivery to a host plant, comprising the steps of:
a) providing two or more nitrogen-fixing microbial species;
b) testing the functional attributes of the microbial species of (a) along at least one of the following dimensions:
i) nutrient utilization;
ii) temporal occupation;
iii) oxygen adaptability; and
iv) spatial occupation;
c) selecting a consortium of at least two microbial species of (a) that differ along at least one of the dimensions tested in (b) for inclusion in the consortium, thereby creating a beneficial consortium of microbes for nitrogen fixation.
In some embodiments, step (b) comprises testing the microbial species' nutrient utilization, and the nutrient is selected from a carbon source or nitrogen source.
In some embodiments, step (b) comprises testing the microbial species' nutrient utilization by measuring growth in at least two different media comprising different nutrients.
In some embodiments, step (b) comprises testing the microbial species' nutrient utilization by measuring each microbe's utilization of different nutrients in a given medium after growing for a time period in that medium, and the medium comprises at least two different nutrients.
In some embodiments, step (b) comprises testing the microbial species' nutrient utilization by measuring each microbe's utilization of different nutrients in a given medium after growing for a time period in that medium, and the medium is derived from a plant rhizosphere, surface plant tissue region, and/or endophytic plant tissue region.
In some embodiments, step (b) comprises testing the microbial species' nutrient utilization by measuring each microbe's utilization of different nutrients in a given medium after growing for a time period in that medium, and the medium is derived from the corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
In some embodiments, step (b) comprises testing the microbial species' temporal occupation.
In some embodiments, step (b) comprises testing the microbial species' temporal occupation by measuring the colonization of each microbial species during different stages of a plant's growing cycle.
In some embodiments, step (b) comprises testing the microbial species' temporal occupation by measuring the colonization of each microbial species during different stages of the corn growing cycle.
In some embodiments, step (b) comprises testing the microbial species' temporal occupation by measuring the colonization of each microbial species during one or more stages of the corn growing cycle selected from VE, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13, V14, V15, V16, VT, R1, R2, R3, R4, R5, and R6.
In some embodiments, step (b) comprises testing the microbial species' temporal occupation by measuring the colonization of each microbial species during one or more periods of the corn growing cycle selected from V4-V6, V6-V10, and V10-V12.
In some embodiments, step (b) comprises testing the microbial species' oxygen adaptability by measuring the nitrogen fixation of each microbial species under different oxygenation conditions.
In some embodiments, step (b) comprises testing the microbial species' oxygen adaptability by measuring the nitrogen fixation of each microbial species under hypoxic, anaerobic, aerobic, and microaerobic conditions.
In some embodiments, step (b) comprises testing the microbial species' oxygen adaptability by measuring the nitrogen fixation of each microbial species under different oxygenation conditions found within a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
In some embodiments, step (b) comprises testing the microbial species' spatial occupation by observing the localization of each microbial species within a plant's rhizosphere, surface plant tissue region, and/or endophytic plant tissue region.
In some embodiments, step (b) comprises testing the microbial species' spatial occupation by observing the localization of each microbial species within a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
In some embodiments, step (b) comprises testing the microbial species' spatial occupation by observing the localization of each microbial species within one or more of the endorhizosphere, the rhizoplane, and the ectorhizosphere.
In some embodiments, step (b) comprises testing the microbial species' spatial occupation by observing the localization of each microbial species within the endorhizosphere.
In some embodiments, step (b) comprises testing the microbial species' spatial occupation by observing the localization of each microbial species within the rhizoplane.
In some embodiments, step (b) comprises testing the microbial species' spatial occupation by observing the localization of each microbial species within the ectorhizosphere.
In some embodiments, step (b) comprises testing the microbial species' spatial occupation by observing the localization of each microbial species within one or more of the root junctions, zone of elongation, root cap, root mucilage, root hairs, root surface, and plant stems of a given plant.
In some embodiments, step (b) comprises testing the microbial species' spatial occupation by observing the localization of each microbial species within one or more of the root junctions, zone of elongation, root cap, root mucilage, root hairs, root surface, and plant stems of corn.
In some embodiments, at least one microbial species comprises heterologous genetic material, whereby the microbial species comprising the heterologous genetic material had improved nitrogen fixation relative to the microbial species without the heterologous genetic material.
In some embodiments, at least one of microbial species lacks genetic material, whereby the microbial species lacking the genetic material has improved nitrogen fixation relative to the microbial species comprising the genetic material.
In some embodiments, at least one microbial species is genetically engineered to fix atmospheric nitrogen and provide such to a host plant.
In some embodiments, at least one microbial species is a remodeled microbe.
In some embodiments, at least one microbial species is a transgenic microbial species.
In some embodiments, at least one microbial species comprises a non-intergeneric genomic modification.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species capable of fixing atmospheric nitrogen in the presence of exogenous nitrogen.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into at least one gene, or non-coding polynucleotide, of the nitrogen fixation or assimilation genetic regulatory network.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising an introduced control sequence operably linked to at least one gene of the nitrogen fixation or assimilation genetic regulatory network.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising a heterologous promoter operably linked to at least one gene of the nitrogen fixation or assimilation genetic regulatory network.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into a gene selected from the group consisting of: nifA, nifL, ntrB, ntrC, polynucleotide encoding glutamine synthetase, glnA, glnB, glnK, drat, amtB, polynucleotide encoding glutaminase, glnD, glnE, nifJ, nifH, nifD, nifK, nifY, nifE, nifN, nifU, nifS, nifV, nifW, nifZ, nifM, nifF, nifB, nifQ, a gene associated with biosynthesis of a nitrogenase enzyme, and combinations thereof.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into at least one gene, or non-coding polynucleotide, of the nitrogen fixation or assimilation genetic regulatory network that results in one or more of: increased expression or activity of NifA or glutaminase; decreased expression or activity of NifL, NtrB, glutamine synthetase, GlnB, GlnK, DraT, AmtB; decreased adenylyl-removing activity of GlnE; or decreased uridylyl-removing activity of GlnD.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising a mutated nifL gene that has been altered to comprise a heterologous promoter inserted into said nifL gene.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising a mutated glnE gene that results in a truncated GlnE protein lacking an adenylyl-removing (AR) domain.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising a mutated amtB gene that results in the lack of expression of said amtB gene.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one of: a mutated nifL gene that has been altered to comprise a heterologous promoter inserted into said nifL gene; a mutated glnE gene that results in a truncated GlnE protein lacking an adenylyl-removing (AR) domain; a mutated amtB gene that results in the lack of expression of said amtB gene; a mutated glnD gene that results in a truncated GlnD protein lacking a uridyl-transferase domain or lack of expression of said glnD gene, and combinations thereof.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into genes involved in a pathway selected from the group consisting of: exopolysaccharide production, endo-polygalaturonase production, trehalose production, and glutamine conversion.
In some embodiments, at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into genes selected from the group consisting of: bcsii, bcsiii, yjbE, fhaB, pehA, otsB, treZ, glsA2, and combinations thereof.
In some embodiments, at least one microbial species is a non-intergeneric remodeled bacterium selected from: Paenibacillus polymyxa, Paraburkholderia tropica, Herbaspirillum aquaticum, Metakosakonia intestini, Rahnella aquatilis, Klebsiella variicola, Achromobacter spiritinus, Achromobacter marplatensis, Microbacterium murale, Kluyvera intermedia, Kosakonia pseudosacchari, Enterobacter sp., Azospirillum lipoferum, Kosakonia sacchari, and combinations thereof.
In some embodiments, at least one microbial species is a non-intergeneric remodeled bacterium selected from: a bacteria deposited as ATCC PTA-126575, a bacteria deposited as ATCC PTA-126576, a bacteria deposited as ATCC PTA-126577, a bacteria deposited as ATCC PTA-126578, a bacteria deposited as ATCC PTA-126579, a bacteria deposited as ATCC PTA-126580, a bacteria deposited as ATCC PTA-126584, a bacteria deposited as ATCC PTA-126586, a bacteria deposited as ATCC PTA-126587, a bacteria deposited as ATCC PTA-126588, a bacteria deposited as NCMA 201701002, a bacteria deposited as NCMA 201708004, a bacteria deposited as NCMA 201708003, a bacteria deposited as NCMA 201708002, a bacteria deposited as NCMA 201712001, a bacteria deposited as NCMA 201712002, a bacteria deposited as PTA-126740, a bacteria deposited as PTA-126743, and combinations thereof.
In some embodiments, at least one microbial species is a non-intergeneric remodeled bacterium comprising a nucleic acid sequence that shares at least about 90%, 95%, or 99% sequence identity to a nucleic acid sequence selected from SEQ ID NOs: 177-260, 296-303, and 458-469.
In some embodiments, at least one microbial species is a non-intergeneric remodeled bacterium comprising a nucleic acid sequence selected from SEQ ID NOs: 177-260, 296-303, and 458-469.
While various embodiments of the disclosure have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions may occur to those skilled in the art without departing from the disclosure. It should be understood that various alternatives to the embodiments of the disclosure described herein may be employed.
Increased fertilizer utilization brings with it environmental concerns and is also likely not possible for many economically stressed regions of the globe. Furthermore, many industry players in the microbial arena are focused on creating intergeneric microbes. However, there is a heavy regulatory burden placed on engineered microbes that are characterized/classified as intergeneric. These intergeneric microbes face not only a higher regulatory burden, which makes widespread adoption and implementation difficult, but they also face a great deal of public perception scrutiny.
Currently, there are no engineered microbes on the market that are non-intergeneric and that are capable of increasing nitrogen fixation in non-leguminous crops. This dearth of such a microbe is a missing element in helping to usher in a truly environmentally friendly and more sustainable 21st century agricultural system.
The present disclosure solves the aforementioned problems and provides a non-intergeneric microbe that has been engineered to readily fix nitrogen in crops. Further, the present disclosure provides novel consortia of microorganisms that may be used to fix nitrogen in crops, providing greater quantities of nitrogen to the crop in combination than the individual microorganisms could alone. The current disclosure identifies individual microorganisms that are believed to be complementary when combined (e.g., because they provide nitrogen at different stages in a crop life cycle). The disclosure teaches the use of the individual microbes for fixing nitrogen, as well as a combination thereof, which, in some embodiments, is expected to provide further benefit in terms of nitrogen delivery to a plant. These consortia may also provide nitrogen to crops over a greater time period or under a greater diversity of (e.g., nutrient) conditions. Each microbe may provide nitrogen at different crop stages, different spatial locations, under different oxygenation conditions, and/or under different nutrient conditions. The combination of microbes may improve the ability to provide nitrogen to the crops over a greater time period in the crop lifecycle and/or under a greater diversity of conditions. Different combinations of the microbes may be used based on the desired crop and conditions under which nitrogen is desired to be provided.
These compositions will serve to help 21st century farmers become less dependent upon utilizing ever increasing amounts of exogenous nitrogen fertilizer.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the disclosure (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. For example, if the range 10-15 is disclosed, then 11, 12, 13, and 14 are also disclosed. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure.
The terms “polynucleotide”, “nucleotide”, “nucleotide sequence”, “nucleic acid” and “oligonucleotide” are used interchangeably. They refer to a polymeric form of nucleotides of any length, either deoxyribonucleotides or ribonucleotides, or analogs thereof. Polynucleotides may have any three dimensional structure, and may perform any function, known or unknown. The following are non-limiting examples of polynucleotides: coding or non-coding regions of a gene or gene fragment, loci (locus) defined from linkage analysis, exons, introns, messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA), short interfering RNA (siRNA), short-hairpin RNA (shRNA), micro-RNA (miRNA), ribozymes, cDNA, recombinant polynucleotides, branched polynucleotides, plasmids, vectors, isolated DNA of any sequence, isolated RNA of any sequence, nucleic acid probes, and primers. A polynucleotide may comprise one or more modified nucleotides, such as methylated nucleotides and nucleotide analogs. If present, modifications to the nucleotide structure may be imparted before or after assembly of the polymer. The sequence of nucleotides may be interrupted by non-nucleotide components. A polynucleotide may be further modified after polymerization, such as by conjugation with a labeling component.
“Hybridization” refers to a reaction in which one or more polynucleotides react to form a complex that is stabilized via hydrogen bonding between the bases of the nucleotide residues. The hydrogen bonding may occur by Watson Crick base pairing, Hoogstein binding, or in any other sequence specific manner according to base complementarity. The complex may comprise two strands forming a duplex structure, three or more strands forming a multi stranded complex, a single self-hybridizing strand, or any combination of these. A hybridization reaction may constitute a step in a more extensive process, such as the initiation of PCR, or the enzymatic cleavage of a polynucleotide by an endonuclease. A second sequence that is complementary to a first sequence is referred to as the “complement” of the first sequence. The term “hybridizable” as applied to a polynucleotide refers to the ability of the polynucleotide to form a complex that is stabilized via hydrogen bonding between the bases of the nucleotide residues in a hybridization reaction.
“Complementarity” refers to the ability of a nucleic acid to form hydrogen bond(s) with another nucleic acid sequence by either traditional Watson-Crick or other non-traditional types. A percent complementarity indicates the percentage of residues in a nucleic acid molecule which can form hydrogen bonds (e.g., Watson-Crick base pairing) with a second nucleic acid sequence (e.g., 5, 6, 7, 8, 9, 10 out of 10 being 50%, 60%, 70%, 80%, 90%, and 100% complementary, respectively). “Perfectly complementary” means that all the contiguous residues of a nucleic acid sequence will hydrogen bond with the same number of contiguous residues in a second nucleic acid sequence. “Substantially complementary” as used herein refers to a degree of complementarity that is at least 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 98%, 99%, or 100% over a region of 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 30, 35, 40, 45, 50, or more nucleotides, or refers to two nucleic acids that hybridize under stringent conditions. Sequence identity, such as for the purpose of assessing percent complementarity, may be measured by any suitable alignment algorithm, including but not limited to the Needleman-Wunsch algorithm (see e.g. the EMBOSS Needle aligner available at www.ebi.ac.uk/Tools/psa/emboss needle/nucleotide.html, optionally with default settings), the BLAST algorithm (see e.g. the BLAST alignment tool available at blast.ncbi.nlm.nih.gov/Blast.cgi, optionally with default settings), or the Smith-Waterman algorithm (see e.g. the EMBOSS Water aligner available at www.ebi.ac.uk/Tools/psa/emboss_water/nucleotide.html, optionally with default settings). Optimal alignment may be assessed using any suitable parameters of a chosen algorithm, including default parameters.
In general, “stringent conditions” for hybridization refer to conditions under which a nucleic acid having complementarity to a target sequence predominantly hybridizes with a target sequence, and substantially does not hybridize to non-target sequences. Stringent conditions are generally sequence-dependent and vary depending on a number of factors. In general, the longer the sequence, the higher the temperature at which the sequence specifically hybridizes to its target sequence. Non-limiting examples of stringent conditions are described in detail in Tijssen (1993), Laboratory Techniques In Biochemistry And Molecular Biology-Hybridization With Nucleic Acid Probes Part I, Second Chapter “Overview of principles of hybridization and the strategy of nucleic acid probe assay”, Elsevier, N.Y.
As used herein, “expression” refers to the process by which a polynucleotide is transcribed from a DNA template (such as into and mRNA or other RNA transcript) and/or the process by which a transcribed mRNA is subsequently translated into peptides, polypeptides, or proteins. Transcripts and encoded polypeptides may be collectively referred to as “gene product.” If the polynucleotide is derived from genomic DNA, expression may include splicing of the mRNA in a eukaryotic cell.
The terms “polypeptide”, “peptide” and “protein” are used interchangeably herein to refer to polymers of amino acids of any length. The polymer may be linear or branched, it may comprise modified amino acids, and it may be interrupted by non-amino acids. The terms also encompass an amino acid polymer that has been modified; for example, disulfide bond formation, glycosylation, lipidation, acetylation, phosphorylation, or any other manipulation, such as conjugation with a labeling component. As used herein the term “amino acid” includes natural and/or unnatural or synthetic amino acids, including glycine and both the D or L optical isomers, and amino acid analogs and peptidomimetics.
As used herein, the term “about” is used synonymously with the term “approximately.” Illustratively, the use of the term “about” with regard to an amount indicates that values slightly outside the cited values, e.g., plus or minus 0.1% to 10%.
The term “biologically pure culture” or “substantially pure culture” refers to a culture of a bacterial species described herein containing no other bacterial species in quantities sufficient to interfere with the replication of the culture or be detected by normal bacteriological techniques.
“Plant productivity” refers generally to any aspect of growth or development of a plant that is a reason for which the plant is grown. For food crops, such as grains or vegetables, “plant productivity” can refer to the yield of grain or fruit harvested from a particular crop. As used herein, improved plant productivity refers broadly to improvements in yield of grain, fruit, flowers, or other plant parts harvested for various purposes, improvements in growth of plant parts, including stems, leaves and roots, promotion of plant growth, maintenance of high chlorophyll content in leaves, increasing fruit or seed numbers, increasing fruit or seed unit weight, reducing NO2 emission due to reduced nitrogen fertilizer usage and similar improvements of the growth and development of plants.
Microbes in and around food crops can influence the traits of those crops. Plant traits that may be influenced by microbes include: yield (e.g., grain production, biomass generation, fruit development, flower set); nutrition (e.g., nitrogen, phosphorus, potassium, iron, micronutrient acquisition); abiotic stress management (e.g., drought tolerance, salt tolerance, heat tolerance); and biotic stress management (e.g., pest, weeds, insects, fungi, and bacteria). Strategies for altering crop traits include: increasing key metabolite concentrations; changing temporal dynamics of microbe influence on key metabolites; linking microbial metabolite production/degradation to new environmental cues; reducing negative metabolites; and improving the balance of metabolites or underlying proteins.
As used herein, a “control sequence” refers to an operator, promoter, silencer, or terminator.
As used herein, “in planta” may refer to in the plant, on the plant, or intimately associated with the plant, depending upon context of usage (e.g. endophytic, epiphytic, or rhizospheric associations). The plant may comprise plant parts, tissue, leaves, roots, root hairs, rhizomes, stems, seed, ovules, pollen, flowers, fruit, etc.
In some embodiments, native or endogenous control sequences of genes of the present disclosure are replaced with one or more intrageneric control sequences.
As used herein, “introduced” refers to the introduction by means of modern biotechnology, and not a naturally occurring introduction.
In some embodiments, the bacteria of the present disclosure have been modified such that they are not naturally occurring bacteria.
In some embodiments, the bacteria of the present disclosure are present in the plant in an amount of at least 103 cfu, 104 cfu, 105 cfu, 106 cfu, 107 cfu, 108 cfu, 109 cfu, 1010 cfu, 1011 cfu, or 1012 cfu per gram of fresh or dry weight of the plant. In some embodiments, the bacteria of the present disclosure are present in the plant in an amount of at least about 103 cfu, about 104 cfu, about 105 cfu, about 106 cfu, about 107 cfu, about 108 cfu, about 109 cfu, about 1010 cfu, about 1011 cfu, or about 1012 cfu per gram of fresh or dry weight of the plant. In some embodiments, the bacteria of the present disclosure are present in the plant in an amount of at least 103 to 109, 103 to 107, 103 to 105, 105 to 109, 105 to 107, 106 to 1010, 106 to 107 cfu per gram of fresh or dry weight of the plant.
Fertilizers and exogenous nitrogen of the present disclosure may comprise the following nitrogen-containing molecules: ammonium, nitrate, nitrite, ammonia, glutamine, etc. Nitrogen sources of the present disclosure may include anhydrous ammonia, ammonia sulfate, urea, diammonium phosphate, urea-form, monoammonium phosphate, ammonium nitrate, nitrogen solutions, calcium nitrate, potassium nitrate, sodium nitrate, etc.
As used herein, “exogenous nitrogen” refers to non-atmospheric nitrogen readily available in the soil, field, or growth medium that is present under non-nitrogen limiting conditions, including ammonia, ammonium, nitrate, nitrite, urea, uric acid, ammonium acids, etc.
As used herein, “non-nitrogen limiting conditions” refers to non-atmospheric nitrogen available in the soil, field, media at concentrations greater than about 4 mM nitrogen, as disclosed by Kant et al. (2010. J. Exp. Biol. 62(4):1499-1509), which is incorporated herein by reference.
As used herein, an “intergeneric microorganism” is a microorganism that is formed by the deliberate combination of genetic material originally isolated from organisms of different taxonomic genera. An “intergeneric mutant” can be used interchangeably with “intergeneric microorganism”. An exemplary “intergeneric microorganism” includes a microorganism containing a mobile genetic element which was first identified in a microorganism in a genus different from the recipient microorganism. Further explanation can be found, inter alia, in 40 C.F.R. § 725.3.
In aspects, microbes taught herein are “non-intergeneric,” which means that the microbes are not intergeneric.
As used herein, an “intrageneric microorganism” is a microorganism that is formed by the deliberate combination of genetic material originally isolated from organisms of the same taxonomic genera. An “intrageneric mutant” can be used interchangeably with “intrageneric microorganism.”
As used herein, “introduced genetic material” means genetic material that is added to, and remains as a component of, the genome of the recipient.
As used herein, in the context of non-intergeneric microorganisms, the term “remodeled” is used synonymously with the term “engineered”. Consequently, a “non-intergeneric remodeled microorganism” has a synonymous meaning to “non-intergeneric engineered microorganism,” and will be utilized interchangeably. Further, the disclosure may refer to an “engineered strain” or “engineered derivative” or “engineered non-intergeneric microbe,” these terms are used synonymously with “remodeled strain” or “remodeled derivative” or “remodeled non-intergeneric microbe.”
In some embodiments, the nitrogen fixation and assimilation genetic regulatory network comprises polynucleotides encoding genes and non-coding sequences that direct, modulate, and/or regulate microbial nitrogen fixation and/or assimilation and can comprise polynucleotide sequences of the nif cluster (e.g., nifA, nijB, nifC, . . . nifZ), polynucleotides encoding nitrogen regulatory protein C, polynucleotides encoding nitrogen regulatory protein B, polynucleotide sequences of the gln cluster (e.g. glnA and glnD), draT, and ammonia transporters/permeases. In some cases, the Nif cluster may comprise NifB, NifH, NifD, NifK, NifE, NifN, NifX, hesa, and NifV. In some cases, the Nif cluster may comprise a subset of NifB, NifH, NifD, NifK, NifE, NifN, NifX, hesa, and NifV.
In some embodiments, fertilizer of the present disclosure comprises at least 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% nitrogen by weight.
In some embodiments, fertilizer of the present disclosure comprises at least about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, about 39%, about 40%, about 41%, about 42%, about 43%, about 44%, about 45%, about 46%, about 47%, about 48%, about 49%, about 50%, about 51%, about 52%, about 53%, about 54%, about 55%, about 56%, about 57%, about 58%, about 59%, about 60%, about 61%, about 62%, about 63%, about 64%, about 65%, about 66%, about 67%, about 68%, about 69%, about 70%, about 71%, about 72%, about 73%, about 74%, about 75%, about 76%, about 77%, about 78%, about 79%, about 80%, about 81%, about 82%, about 83%, about 84%, about 85%, about 86%, about 87%, about 88%, about 89%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, or about 99% nitrogen by weight.
In some embodiments, fertilizer of the present disclosure comprises about 5% to 50%, about 5% to 75%, about 10% to 50%, about 10% to 75%, about 15% to 50%, about 15% to 75%, about 20% to 50%, about 20% to 75%, about 25% to 50%, about 25% to 75%, about 30% to 50%, about 30% to 75%, about 35% to 50%, about 35% to 75%, about 40% to 50%, about 40% to 75%, about 45% to 50%, about 45% to 75%, or about 50% to 75% nitrogen by weight.
In some embodiments, the increase of nitrogen fixation and/or the production of 1% or more of the nitrogen in the plant are measured relative to control plants, which have not been exposed to the bacteria of the present disclosure. All increases or decreases in bacteria are measured relative to control bacteria. All increases or decreases in plants are measured relative to control plants.
As used herein, a “constitutive promoter” is a promoter, which is active under most conditions and/or during most development stages. There are several advantages to using constitutive promoters in expression vectors used in biotechnology, such as: high level of production of proteins used to select transgenic cells or organisms; high level of expression of reporter proteins or scorable markers, allowing easy detection and quantification; high level of production of a transcription factor that is part of a regulatory transcription system; production of compounds that requires ubiquitous activity in the organism; and production of compounds that are required during all stages of development. Non-limiting exemplary constitutive promoters include, CaMV 35S promoter, opine promoters, ubiquitin promoter, alcohol dehydrogenase promoter, etc.
As used herein, a “non-constitutive promoter” is a promoter which is active under certain conditions, in certain types of cells, and/or during certain development stages. For example, tissue specific, tissue preferred, cell type specific, cell type preferred, inducible promoters, and promoters under development control are non-constitutive promoters. Examples of promoters under developmental control include promoters that preferentially initiate transcription in certain tissues.
As used herein, “inducible” or “repressible” promoter is a promoter which is under chemical or environmental factors control. Examples of environmental conditions that may affect transcription by inducible promoters include anaerobic conditions, certain chemicals, the presence of light, acidic or basic conditions, etc.
As used herein, a “tissue specific” promoter is a promoter that initiates transcription only in certain tissues. Unlike constitutive expression of genes, tissue-specific expression is the result of several interacting levels of gene regulation. As such, in the art sometimes it is preferable to use promoters from homologous or closely related species to achieve efficient and reliable expression of transgenes in particular tissues. This is one of the main reasons for the large amount of tissue-specific promoters isolated from particular tissues found in both scientific and patent literature.
As used herein, the term “operably linked” refers to the association of nucleic acid sequences on a single nucleic acid fragment so that the function of one is regulated by the other. For example, a promoter is operably linked with a coding sequence when it is capable of regulating the expression of that coding sequence (i.e., that the coding sequence is under the transcriptional control of the promoter). Coding sequences can be operably linked to regulatory sequences in a sense or antisense orientation. In another example, the complementary RNA regions of the disclosure can be operably linked, either directly or indirectly, 5′ to the target mRNA, or 3′ to the target mRNA, or within the target mRNA, or a first complementary region is 5′ and its complement is 3′ to the target mRNA.
In aspects, “applying to the plant a plurality of non-intergeneric bacteria,” includes any means by which the plant (including plant parts such as a seed, root, stem, tissue, etc.) is made to come into contact (i.e. exposed) with said bacteria at any stage of the plant's life cycle. Consequently, “applying to the plant a plurality of non-intergeneric bacteria,” includes any of the following means of exposing the plant (including plant parts such as a seed, root, stem, tissue, etc.) to said bacteria: spraying onto plant, dripping onto plant, applying as a seed coat, applying to a field that will then be planted with seed, applying to a field already planted with seed, applying to a field with adult plants, etc. More generally, “applying to the plant a plurality of microorganisms,” such as those comprised by the consortia disclosed herein, includes any of the foregoing routes and means of application.
As used herein “MRTN” is an acronym for maximum return to nitrogen and is utilized as an experimental treatment in the Examples. MRTN was developed by Iowa State University and information can be found at: cnrc.agron.iastate.edu/. The MRTN is the nitrogen rate where the economic net return to nitrogen application is maximized. The approach to calculating the MRTN is a regional approach for developing corn nitrogen rate guidelines in individual states. The nitrogen rate trial data was evaluated for Illinois, Iowa, Michigan, Minnesota, Ohio, and Wisconsin where an adequate number of research trials were available for corn plantings following soybean and corn plantings following corn. The trials were conducted with spring, sidedress, or split preplant/sidedress applied nitrogen, and sites were not irrigated except for those that were indicated for irrigated sands in Wisconsin. MRTN was developed by Iowa State University due to apparent differences in methods for determining suggested nitrogen rates required for corn production, misperceptions pertaining to nitrogen rate guidelines, and concerns about application rates. By calculating the MRTN, practitioners can determine the following: (1) the nitrogen rate where the economic net return to nitrogen application is maximized, (2) the economic optimum nitrogen rate, which is the point where the last increment of nitrogen returns a yield increase large enough to pay for the additional nitrogen, (3) the value of corn grain increase attributed to nitrogen application, and the maximum yield, which is the yield where application of more nitrogen does not result in a corn yield increase. Thus the MRTN calculations provide practitioners with the means to maximize corn crops in different regions while maximizing financial gains from nitrogen applications.
The term mmol is an abbreviation for millimole, which is a thousandth (10−3) of a mole, abbreviated herein as mol.
As used herein the term “plant” can include plant parts, tissue, leaves, roots, root hairs, rhizomes, stems, seeds, ovules, pollen, flowers, fruit, etc. Thus, when the disclosure discusses providing a plurality of corn plants to a particular locus, it is understood that this may entail planting a corn seed at a particular locus.
As used herein the terms “microorganism” or “microbe” should be taken broadly. These terms, used interchangeably, include but are not limited to, the two prokaryotic domains, Bacteria and Archaea. The term may also encompass eukaryotic fungi and protists.
As used herein, when the disclosure discuses a particular microbial deposit by accession number, it is understood that the disclosure also contemplates a microbial strain having all of the identifying characteristics of said deposited microbe, and/or a mutant thereof.
The term “microbial consortia” or “microbial consortium” refers to a subset of a microbial community of individual microbial species, or strains of a species, which can be described as carrying out a common function, or can be described as participating in, or leading to, or correlating with, a recognizable parameter, such as a phenotypic trait of interest.
The term “microbial community” means a group of microbes comprising two or more species or strains. Unlike microbial consortia, a microbial community does not have to be carrying out a common function, or does not have to be participating in, or leading to, or correlating with, a recognizable parameter, such as a phenotypic trait of interest.
As used herein, “isolate,” “isolated,” “isolated microbe,” and like terms, are intended to mean that the one or more microorganisms has been separated from at least one of the materials with which it is associated in a particular environment (for example soil, water, plant tissue, etc.). Thus, an “isolated microbe” does not exist in its naturally occurring environment; rather, it is through the various techniques described herein that the microbe has been removed from its natural setting and placed into a non-naturally occurring state of existence. Thus, the isolated strain or isolated microbe may exist as, for example, a biologically pure culture, or as spores (or other forms of the strain). In aspects, the isolated microbe may be in association with an acceptable carrier, which may be an agriculturally acceptable carrier.
In certain aspects of the disclosure, the isolated microbes exist as “isolated and biologically pure cultures.” It will be appreciated by one of skill in the art, that an isolated and biologically pure culture of a particular microbe, denotes that said culture is substantially free of other living organisms and contains only the individual microbe in question. The culture can contain varying concentrations of said microbe. The present disclosure notes that isolated and biologically pure microbes often “necessarily differ from less pure or impure materials.” See, e.g. In re Bergstrom, 427 F.2d 1394, (CCPA 1970)(discussing purified prostaglandins), see also, In re Bergy, 596 F.2d 952 (CCPA 1979)(discussing purified microbes), see also, Parke-Davis & Co. v. H. K. Mulford & Co., 189 F. 95 (S.D.N.Y. 1911) (Learned Hand discussing purified adrenaline), aff′d in part, rev′d in part, 196 F. 496 (2d Cir. 1912), each of which are incorporated herein by reference. Furthermore, in some aspects, the disclosure provides for certain quantitative measures of the concentration, or purity limitations, that must be found within an isolated and biologically pure microbial culture. The presence of these purity values, in certain embodiments, is a further attribute that distinguishes the presently disclosed microbes from those microbes existing in a natural state. See, e.g., Merck & Co. v. Olin Mathieson Chemical Corp., 253 F.2d 156 (4th Cir. 1958) (discussing purity limitations for vitamin B12 produced by microbes), incorporated herein by reference.
As used herein, “individual isolates” should be taken to mean a composition, or culture, comprising a predominance of a single genera, species, or strain, of microorganism, following separation from one or more other microorganisms.
Microbes of the present disclosure may include spores and/or vegetative cells. In some embodiments, microbes of the present disclosure include microbes in a viable but non-culturable (VBNC) state. As used herein, “spore” or “spores” refer to structures produced by bacteria and fungi that are adapted for survival and dispersal. Spores are generally characterized as dormant structures; however, spores are capable of differentiation through the process of germination. Germination is the differentiation of spores into vegetative cells that are capable of metabolic activity, growth, and reproduction. The germination of a single spore results in a single fungal or bacterial vegetative cell. Fungal spores are units of asexual reproduction, and in some cases are necessary structures in fungal life cycles. Bacterial spores are structures for surviving conditions that may ordinarily be nonconducive to the survival or growth of vegetative cells.
As used herein, “microbial composition” refers to a composition comprising one or more microbes of the present disclosure. In some embodiments, a microbial composition is administered to plants (including various plant parts) and/or in agricultural fields.
As used herein, “carrier,” “acceptable carrier,” or “agriculturally acceptable carrier” refers to a diluent, adjuvant, excipient, or vehicle with which the microbe can be administered, which does not detrimentally effect the microbe.
In some embodiments, the microbes and/or genetic modifications disclosed herein are not the microbes taught in PCT/US2018/013671 (WO 2018/132774 A1), filed Jan. 12, 2018, and entitled: Methods and Compositions for Improving Plant Traits. In some embodiments, the methods disclosed herein are not the methods taught in PCT/US2018/013671 (WO 2018/132774 A1), filed Jan. 12, 2018, and entitled: Methods and Compositions for Improving Plant Traits. Thus, the present disclosure contemplates embodiments, which have a negative proviso of the microbes, methods, and gene modifications disclosed in said application.
Regulation of Nitrogen Fixation
In some cases, nitrogen fixation pathway may act as a target for genetic engineering and optimization. One trait that may be targeted for regulation by the methods described herein is nitrogen fixation. Nitrogen fertilizer is the largest operational expense on a farm and the biggest driver of higher yields in row crops like corn and wheat. Described herein are microbial products that can deliver renewable forms of nitrogen in non-leguminous crops. While some endophytes have the genetics necessary for fixing nitrogen in pure culture, the fundamental technical challenge is that wild-type endophytes of cereals and grasses stop fixing nitrogen in fertilized fields. The application of chemical fertilizers and residual nitrogen levels in field soils signal the microbe to shut down the biochemical pathway for nitrogen fixation.
Changes to the transcriptional and post-translational levels of components of the nitrogen fixation regulatory network may be beneficial to the development of a microbe capable of fixing and transferring nitrogen to corn in the presence of fertilizer. To that end, described herein is Host-Microbe Evolution (HoME) technology to precisely evolve regulatory networks and elicit novel phenotypes. Also described herein are unique, proprietary libraries of nitrogen-fixing endophytes isolated from corn, paired with extensive omics data surrounding the interaction of microbes and host plant under different environmental conditions like nitrogen stress and excess. In some embodiments, this technology enables precision evolution of the genetic regulatory network of endophytes to produce microbes that actively fix nitrogen even in the presence of fertilizer in the field. Also described herein are evaluations of the technical potential of evolving microbes that colonize corn root tissues and produce nitrogen for fertilized plants and evaluations of the compatibility of endophytes with standard formulation practices and diverse soils to determine feasibility of integrating the microbes into modern nitrogen management strategies.
In order to utilize elemental nitrogen (N) for chemical synthesis, life forms combine nitrogen gas (N2) available in the atmosphere with hydrogen in a process known as nitrogen fixation. Because of the energy-intensive nature of biological nitrogen fixation, diazotrophs (bacteria and archaea that fix atmospheric nitrogen gas) have evolved sophisticated and tight regulation of the nif gene cluster in response to environmental oxygen and available nitrogen. Nif genes encode enzymes involved in nitrogen fixation (such as the nitrogenase complex) and proteins that regulate nitrogen fixation. Shamseldin (2013. Global J. Biotechnol. Biochem. 8(4):84-94) discloses detailed descriptions of nif genes and their products, and is incorporated herein by reference. Described herein are methods of producing a plant with an improved trait comprising isolating bacteria from a first plant, introducing a genetic variation into a gene of the isolated bacteria to increase nitrogen fixation, exposing a second plant to the variant bacteria, isolating bacteria from the second plant having an improved trait relative to the first plant, and repeating the steps with bacteria isolated from the second plant.
In Proteobacteria, regulation of nitrogen fixation centers around the σ54-dependent enhancer-binding protein NifA, the positive transcriptional regulator of the nif cluster. Intracellular levels of active NifA are controlled by two key factors: transcription of the nifLA operon, and inhibition of NifA activity by protein-protein interaction with NifL. Both of these processes are responsive to intracellular glutamine levels via the PII protein signaling cascade. This cascade is mediated by GlnD, which directly senses glutamine and catalyzes the uridylylation or deuridylylation of two PII regulatory proteins—GlnB and GlnK—in response the absence or presence, respectively, of bound glutamine. Under conditions of nitrogen excess, unmodified GlnB signals the deactivation of the nifLA promoter. However, under conditions of nitrogen limitation, GlnB is post-translationally modified, which inhibits its activity and leads to transcription of the nifLA operon. In this way, nifLA transcription is tightly controlled in response to environmental nitrogen via the PII protein signaling cascade. On the post-translational level of NifA regulation, GlnK inhibits the NifL/NifA interaction in a matter dependent on the overall level of free GlnK within the cell.
NifA is transcribed from the nifLA operon, whose promoter is activated by phosphorylated NtrC, another 654-dependent regulator. The phosphorylation state of NtrC is mediated by the histidine kinase NtrB, which interacts with deuridylylated GlnB but not uridylylated GlnB. Under conditions of nitrogen excess, a high intracellular level of glutamine leads to deuridylylation of GlnB, which then interacts with NtrB to deactivate its phosphorylation activity and activate its phosphatase activity, resulting in dephosphorylation of NtrC and the deactivation of the nifLA promoter. However, under conditions of nitrogen limitation, a low level of intracellular glutamine results in uridylylation of GlnB, which inhibits its interaction with NtrB and allows the phosphorylation of NtrC and transcription of the nifLA operon. In this way, nifLA expression is tightly controlled in response to environmental nitrogen via the PII protein signaling cascade. nifA, ntrB, ntrC, and glnB, are all genes that can be mutated in the methods described herein. These processes may also be responsive to intracellular or extracellular levels of ammonia, urea or nitrates.
The activity of NifA is also regulated post-translationally in response to environmental nitrogen, most typically through NifL-mediated inhibition of NifA activity. In general, the interaction of NifL and NifA is influenced by the PII protein signaling cascade via GlnK, although the nature of the interactions between GlnK and NifL/NifA varies significantly between diazotrophs. In Klebsiella pneumoniae, both forms of GlnK inhibit the NifL/NifA interaction, and the interaction between GlnK and NifL/NifA is determined by the overall level of free GlnK within the cell. Under nitrogen-excess conditions, deuridylylated GlnK interacts with the ammonium transporter AmtB, which serves to both block ammonium uptake by AmtB and sequester GlnK to the membrane, allowing inhibition of NifA by NifL. On the other hand, in Azotobacter vinelandii, interaction with deuridylylated GlnK is required for the NifL/NifA interaction and NifA inhibition, while uridylylation of GlnK inhibits its interaction with NifL. In diazotrophs lacking the nifL gene, there is evidence that NifA activity is inhibited directly by interaction with the deuridylylated forms of both GlnK and GlnB under nitrogen-excess conditions. In some bacteria the Nif cluster may be regulated by glnR, and further in some cases this may comprise negative regulation. Regardless of the mechanism, post-translational inhibition of NifA is an important regulator of the nif cluster in most known diazotrophs. Additionally, nifL, amtB, glnK, and glnR are genes that can be mutated in the methods described herein.
In addition to regulating the transcription of the nif gene cluster, many diazotrophs have evolved a mechanism for the direct post-translational modification and inhibition of the nitrogenase enzyme itself, known as nitrogenase shutoff. This is mediated by ADP-ribosylation of the Fe protein (NifH) under nitrogen-excess conditions, which disrupts its interaction with the MoFe protein complex (NifDK) and abolishes nitrogenase activity. DraT catalyzes the ADP-ribosylation of the Fe protein and shutoff of nitrogenase, while DraG catalyzes the removal of ADP-ribose and reactivation of nitrogenase. As with nifLA transcription and NifA inhibition, nitrogenase shutoff is also regulated via the PII protein signaling cascade. Under nitrogen-excess conditions, deuridylylated GlnB interacts with and activates DraT, while deuridylylated GlnK interacts with both DraG and AmtB to form a complex, sequestering DraG to the membrane. Under nitrogen-limiting conditions, the uridylylated forms of GlnB and GlnK do not interact with DraT and DraG, respectively, leading to the inactivation of DraT and the diffusion of DraG to the Fe protein, where it removes the ADP-ribose and activates nitrogenase. The methods described herein also contemplate introducing genetic variation into the nifH, nifD, and draT genes.
Although some endophytes have the ability to fix nitrogen in vitro, often the genetics are silenced in the field by high levels of exogenous chemical fertilizers. One can decouple the sensing of exogenous nitrogen from expression of the nitrogenase enzyme to facilitate field-based nitrogen fixation. Improving the integral of nitrogenase activity across time further serves to augment the production of nitrogen for utilization by the crop. Specific targets for genetic variation to facilitate field-based nitrogen fixation using the methods described herein include one or more genes selected from the group consisting of nifA, nifL, ntrB, ntrC, glnA, glnB, glnK, draT, amtB, glnD, glnE, nifJ, nifH, nifD, nifK, nifY, nifE, nifN, nifU, nifS, nifV, nifW, nifZ, nifM, nifF, nifB, and nifQ.
An additional target for genetic variation to facilitate field-based nitrogen fixation using the methods described herein is the NifA protein. The NifA protein is typically the activator for expression of nitrogen fixation genes. Increasing the production of NifA (either constitutively or during high ammonia condition) circumvents the native ammonia-sensing pathway. In addition, reducing the production of NifL proteins, a known inhibitor of NifA, also leads to an increased level of freely active NifA. In addition, increasing the transcription level of the nifAL operon (either constitutively or during high ammonia condition) also leads to an overall higher level of NifA proteins. Elevated level of nifAL expression is achieved by altering the promoter itself or by reducing the expression of NtrB (part of ntrB and ntrC signaling cascade that originally would result in the shutoff of nifAL operon during high nitrogen condition). High level of NifA achieved by these or any other methods described herein increases the nitrogen fixation activity of the endophytes.
Another target for genetic variation to facilitate field-based nitrogen fixation using the methods described herein is the GlnD/GlnB/GlnK PII signaling cascade. The intracellular glutamine level is sensed through the GlnD/GlnB/GlnK PII signaling cascade. Active site mutations in GlnD that abolish the uridylyl-removing activity of GlnD disrupt the nitrogen-sensing cascade. In addition, reduction of the GlnB concentration short circuits the glutamine-sensing cascade. These mutations “trick” the cells into perceiving a nitrogen-limited state, thereby increasing the nitrogen fixation level activity. These processes may also be responsive to intracellular or extracellular levels of ammonia, urea or nitrates.
The amtB protein is also a target for genetic variation to facilitate field-based nitrogen fixation using the methods described herein. Ammonia uptake from the environment can be reduced by decreasing the expression level of amtB protein. Without intracellular ammonia, the endophyte is not able to sense the high level of ammonia, preventing the down-regulation of nitrogen fixation genes. Any ammonia that manages to get into the intracellular compartment is converted into glutamine. Intracellular glutamine level is the major currency of nitrogen sensing. Decreasing the intracellular glutamine level prevents the cells from sensing high ammonium levels in the environment. This effect can be achieved by increasing the expression level of glutaminase, an enzyme that converts glutamine into glutamate. In addition, intracellular glutamine can also be reduced by decreasing glutamine synthase (an enzyme that converts ammonia into glutamine). In diazotrophs, fixed ammonia is quickly assimilated into glutamine and glutamate to be used for cellular processes. Disruptions to ammonia assimilation may enable diversion of fixed nitrogen to be exported from the cell as ammonia. The fixed ammonia is predominantly assimilated into glutamine by glutamine synthetase (GS), encoded by glnA, and subsequently into glutamine by glutamine oxoglutarate aminotransferase (GOGAT). In some examples, glnS encodes a glutamine synthetase. GS is regulated post-translationally by GS adenylyl transferase (GlnE), a bi-functional enzyme encoded by glnE that catalyzes both the adenylylation and de-adenylylation of GS through activity of its adenylyl-transferase (AT) and adenylyl-removing (AR) domains, respectively. Under nitrogen limiting conditions, glnA is expressed, and GlnE's AR domain de-adynylylates GS, allowing it to be active. Under conditions of nitrogen excess, glnA expression is turned off, and GlnE's AT domain is activated allosterically by glutamine, causing the adenylylation and deactivation of GS.
Furthermore, the draT gene may also be a target for genetic variation to facilitate field-based nitrogen fixation using the methods described herein. Once nitrogen fixing enzymes are produced by the cell, nitrogenase shut-off represents another level in which cell downregulates fixation activity in high nitrogen condition. This shut-off could be removed by decreasing the expression level of DraT.
Methods for imparting new microbial phenotypes can be performed at the transcriptional, translational, and post-translational levels. The transcriptional level includes changes at the promoter (such as changing sigma factor affinity or binding sites for transcription factors, including deletion of all or a portion of the promoter) or changing transcription terminators and attenuators. The translational level includes changes at the ribosome binding sites and changing mRNA degradation signals. The post-translational level includes mutating an enzyme's active site and changing protein-protein interactions. These changes can be achieved in a multitude of ways. Reduction of expression level (or complete abolishment) can be achieved by swapping the native ribosome binding site (RBS) or promoter with another with lower strength/efficiency. ATG start sites can be swapped to a GTG, TTG, or CTG start codon, which results in reduction in translational activity of the coding region. Complete abolishment of expression can be done by knocking out (deleting) the coding region of a gene. Frameshifting the open reading frame (ORF) likely will result in a premature stop codon along the ORF, thereby creating a non-functional truncated product. Insertion of in-frame stop codons will also similarly create a non-functional truncated product. Addition of a degradation tag at the N or C terminal can also be done to reduce the effective concentration of a particular gene.
Conversely, expression level of the genes described herein can be achieved by using a stronger promoter. To ensure high promoter activity during high nitrogen level condition (or any other condition), a transcription profile of the whole genome in a high nitrogen level condition could be obtained and active promoters with a desired transcription level can be chosen from that dataset to replace the weak promoter. Weak start codons can be swapped out with an ATG start codon for better translation initiation efficiency. Weak ribosomal binding sites (RBS) can also be swapped out with a different RBS with higher translation initiation efficiency. In addition, site-specific mutagenesis can also be performed to alter the activity of an enzyme.
Increasing the level of nitrogen fixation that occurs in a plant can lead to a reduction in the amount of chemical fertilizer needed for crop production and reduce greenhouse gas emissions (e.g., nitrous oxide).
One trait that may be targeted for regulation by the methods described herein is colonization potential. Accordingly, in some embodiments, pathways and genes involved in colonization may act as a target for genetic engineering and optimization.
In some cases, exopolysaccharides may be involved in bacterial colonization of plants. In some cases, plant colonizing microbes may produce a biofilm. In some cases, plant colonizing microbes secrete molecules which may assist in adhesion to the plant, or in evading a plant immune response. In some cases, plant colonizing microbes may excrete signaling molecules which alter the plants response to the microbes. In some cases, plant colonizing microbes may secrete molecules which alter the local microenvironment. In some cases, a plant colonizing microbe may alter expression of genes to adapt to a plant said microbe is in proximity to. In some cases, a plant colonizing microbe may detect the presence of a plant in the local environment and may change expression of genes in response.
In some embodiments, to improve colonization, a gene involved in a pathway selected from the group consisting of: exopolysaccharide production, endo-polygalaturonase production, trehalose production, and glutamine conversion may be targeted for genetic engineering and optimization.
In some embodiments, an enzyme or pathway involved in production of exopolysaccharides may be genetically modified to improve colonization. Exemplary genes encoding an exopolysaccharide producing enzyme that may be targeted to improve colonization include, but are not limited to, bcsii, bcsiii, and yjbE.
In some embodiments, an enzyme or pathway involved in production of a filamentous hemagglutinin may be genetically modified to improve colonization. For example, fhaB gene encoding a filamentous hemagglutinin may be targeted to improve colonization.
In some embodiments, an enzyme or pathway involved in production of an endo-polygalaturonase may be genetically modified to improve colonization. For example, a pehA gene encoding an endo-polygalaturonase precursor may be targeted to improve colonization.
In some embodiments, an enzyme or pathway involved in production of trehalose may be genetically modified to improve colonization. Exemplary genes encoding a trehalose producing enzyme that may be targeted to improve colonization include, but are not limited to, otsB and treZ.
In some embodiments, an enzyme or pathway involved in conversion of glutamine may be genetically modified to improve colonization. For example, the glsA2 gene encodes a glutaminase which converts glutamine into ammonium and glutamate. Upregulating glsA2 improves fitness by increasing the cell's glutamate pool, thereby increasing available N to the cells. Accordingly, in some embodiments, the glsA2 gene may be targeted to improve colonization.
In some embodiments, colonization genes selected from the group consisting of: bcsii, bcsiii, yjbE, fhaB, pehA, otsB, treZ, glsA2, and combinations thereof, may be genetically modified to improve colonization.
Colonization genes that may be targeted to improve the colonization potential are also described in a PCT publication, WO/2019/032926, which is incorporated by reference herein in its entirety.
Microbes useful in methods and compositions disclosed herein can be obtained by extracting microbes from surfaces or tissues of native plants. Microbes can be obtained by grinding seeds to isolate microbes. Microbes can be obtained by planting seeds in diverse soil samples and recovering microbes from tissues. Additionally, microbes can be obtained by inoculating plants with exogenous microbes and determining which microbes appear in plant tissues. Non-limiting examples of plant tissues may include a seed, seedling, leaf, cutting, plant, bulb, or tuber.
A method of obtaining microbes may be through the isolation of bacteria from soils. Bacteria may be collected from various soil types. In some example, the soil can be characterized by traits such as high or low fertility, levels of moisture, levels of minerals, and various cropping practices. For example, the soil may be involved in a crop rotation where different crops are planted in the same soil in successive planting seasons. The sequential growth of different crops on the same soil may prevent disproportionate depletion of certain minerals. The bacteria can be isolated from the plants growing in the selected soils. The seedling plants can be harvested at 2-6 weeks of growth. For example, at least 400 isolates can be collected in a round of harvest. Soil and plant types reveal the plant phenotype as well as the conditions, which allow for the downstream enrichment of certain phenotypes.
Microbes can be isolated from plant tissues to assess microbial traits. The parameters for processing tissue samples may be varied to isolate different types of associative microbes, such as rhizospheric bacteria, epiphytes, or endophytes. The isolates can be cultured in nitrogen-free media to enrich for bacteria that perform nitrogen fixation. Alternatively, microbes can be obtained from global strain banks.
In planta analytics are performed to assess microbial traits. In some embodiments, the plant tissue can be processed for screening by high throughput processing for DNA and RNA. Additionally, non-invasive measurements can be used to assess plant characteristics, such as colonization. Measurements on wild microbes can be obtained on a plant-by-plant basis. Measurements on wild microbes can also be obtained in the field using medium throughput methods. Measurements can be done successively over time. Model plant system can be used including, but not limited to, Setaria.
Microbes in a plant system can be screened via transcriptional profiling of a microbe in a plant system. Examples of screening through transcriptional profiling are using methods of quantitative polymerase chain reaction (qPCR), molecular barcodes for transcript detection, Next Generation Sequencing, and microbe tagging with fluorescent markers. Impact factors can be measured to assess colonization in the greenhouse including, but not limited to, microbiome, abiotic factors, soil conditions, oxygen, moisture, temperature, inoculum conditions, and root localization. Nitrogen fixation can be assessed in bacteria by measuring 15N gas/fertilizer (dilution) with IRMS or NanoSIMS as described herein NanoSIMS is high-resolution secondary ion mass spectrometry. The NanoSIMS technique is a way to investigate chemical activity from biological samples. The catalysis of reduction of oxidation reactions that drive the metabolism of microorganisms can be investigated at the cellular, subcellular, molecular and elemental level. NanoSIMS can provide high spatial resolution of greater than 0.1 μm. NanoSIMS can detect the use of isotope tracers such as 13C, 15N, and 18O. Therefore, NanoSIMS can be used to the chemical activity nitrogen in the cell.
Automated greenhouses can be used for planta analytics. Plant metrics in response to microbial exposure include, but are not limited to, biomass, chloroplast analysis, CCD camera, volumetric tomography measurements.
One way of enriching a microbe population is according to genotype. For example, a polymerase chain reaction (PCR) assay with a targeted primer or specific primer. Primers designed for the nifH gene can be used to identity diazotrophs because diazotrophs express the nifH gene in the process of nitrogen fixation. A microbial population can also be enriched via single-cell culture-independent approaches and chemotaxis-guided isolation approaches. Alternatively, targeted isolation of microbes can be performed by culturing the microbes on selection media. Premeditated approaches to enriching microbial populations for desired traits can be guided by bioinformatics data and are described herein.
Enriching for Microbes with Nitrogen Fixation Capabilities Using Bioinformatics
Bioinformatics tools can be used to identify and isolate plant growth promoting rhizobacteria (PGPRs), which are selected based on their ability to perform nitrogen fixation. Microbes with high nitrogen fixing ability can promote favorable traits in plants. Bioinformatics modes of analysis for the identification of PGPRs include, but are not limited to, genomics, metagenomics, targeted isolation, gene sequencing, transcriptome sequencing, and modeling.
Genomics analysis can be used to identify PGPRs and confirm the presence of mutations with methods of Next Generation Sequencing as described herein and microbe version control.
Metagenomics can be used to identify and isolate PGPR using a prediction algorithm for colonization. Metadata can also be used to identify the presence of an engineered strain in environmental and greenhouse samples.
Transcriptomic sequencing can be used to predict genotypes leading to PGPR phenotypes. Additionally, transcriptomic data is used to identify promoters for altering gene expression. Transcriptomic data can be analyzed in conjunction with the Whole Genome Sequence (WGS) to generate models of metabolism and gene regulatory networks.
Microbes isolated from nature can undergo a domestication process wherein the microbes are converted to a form that is genetically trackable and identifiable. One way to domesticate a microbe is to engineer it with antibiotic resistance. The process of engineering antibiotic resistance can begin by determining the antibiotic sensitivity in the wild type microbial strain. If the bacteria are sensitive to the antibiotic, then the antibiotic can be a good candidate for antibiotic resistance engineering. Subsequently, an antibiotic resistant gene or a counterselectable suicide vector can be incorporated into the genome of a microbe using recombineering methods. A counterselectable suicide vector may consist of a deletion of the gene of interest, a selectable marker, and the counterselectable marker sacB. Counterselection can be used to exchange native microbial DNA sequences with antibiotic resistant genes. A medium throughput method can be used to evaluate multiple microbes simultaneously allowing for parallel domestication. Alternative methods of domestication include the use of homing nucleases to prevent the suicide vector sequences from looping out or from obtaining intervening vector sequences.
DNA vectors can be introduced into bacteria via several methods including electroporation and chemical transformations. A standard library of vectors can be used for transformations. An example of a method of gene editing is CRISPR preceded by Cas9 testing to ensure activity of Cas9 in the microbes.
A microbial population with favorable traits can be obtained via directed evolution. Direct evolution is an approach wherein the process of natural selection is mimicked to evolve proteins or nucleic acids towards a user-defined goal. An example of direct evolution is when random mutations are introduced into a microbial population, the microbes with the most favorable traits are selected, and the growth of the selected microbes is continued. The most favorable traits in growth promoting rhizobacteria (PGPRs) may be in nitrogen fixation. The method of directed evolution may be iterative and adaptive based on the selection process after each iteration.
Plant growth promoting rhizobacteria (PGPRs) with high capability of nitrogen fixation can be generated. The evolution of PGPRs can be carried out via the introduction of genetic variation. Genetic variation can be introduced via polymerase chain reaction mutagenesis, oligonucleotide-directed mutagenesis, saturation mutagenesis, fragment shuffling mutagenesis, homologous recombination, CRISPR/Cas9 systems, chemical mutagenesis, and combinations thereof. These approaches can introduce random mutations into the microbial population. For example, mutants can be generated using synthetic DNA or RNA via oligonucleotide-directed mutagenesis. Mutants can be generated using tools contained on plasmids, which are later cured. Genes of interest can be identified using libraries from other species with improved traits including, but not limited to, improved PGPR properties, improved colonization of cereals, increased oxygen sensitivity, increased nitrogen fixation, and increased ammonia excretion. Intrageneric genes can be designed based on these libraries using software such as Geneious or Platypus design software. Mutations can be designed with the aid of machine learning. Mutations can be designed with the aid of a metabolic model. Automated design of the mutation can be done using a la Platypus and will guide RNAs for Cas-directed mutagenesis.
The intra-generic genes can be transferred into the host microbe. Additionally, reporter systems can also be transferred to the microbe. The reporter systems characterize promoters, determine the transformation success, screen mutants, and act as negative screening tools.
The microbes carrying the mutation can be cultured via serial passaging. A microbial colony contains a single variant of the microbe. Microbial colonies are screened with the aid of an automated colony picker and liquid handler. Mutants with gene duplication and increased copy number express a higher genotype of the desired trait.
The microbial colonies can be screened using various assays to assess nitrogen fixation. One way to measure nitrogen fixation is via a single fermentative assay, which measures nitrogen excretion. An alternative method is the acetylene reduction assay (ARA) with in-line sampling over time. ARA can be performed in high throughput plates of microtube arrays. ARA can be performed with live plants and plant tissues. The media formulation and media oxygen concentration can be varied in ARA assays. Another method of screening microbial variants is by using biosensors. The use of NanoSIMS and Raman microspectroscopy can be used to investigate the activity of the microbes. In some cases, bacteria can also be cultured and expanded using methods of fermentation in bioreactors. The bioreactors are designed to improve robustness of bacteria growth and to decrease the sensitivity of bacteria to oxygen. Medium to high TP plate-based microfermentors are used to evaluate oxygen sensitivity, nutritional needs, nitrogen fixation, and nitrogen excretion. The bacteria can also be co-cultured with competitive or beneficial microbes to elucidate cryptic pathways. Flow cytometry can be used to screen for bacteria that produce high levels of nitrogen using chemical, colorimetric, or fluorescent indicators. The bacteria may be cultured in the presence or absence of a nitrogen source. For example, the bacteria may be cultured with glutamine, ammonia, urea or nitrates.
Guided microbial remodeling is a method to systematically identify and improve the role of species within the crop microbiome. In some aspects, and according to a particular methodology of grouping/categorization, the method comprises three steps: 1) selection of candidate species by mapping plant-microbe interactions and predicting regulatory networks linked to a particular phenotype, 2) pragmatic and predictable improvement of microbial phenotypes through intra-species crossing of regulatory networks and gene clusters within a microbe's genome, and 3) screening and selection of new microbial genotypes that produce desired crop phenotypes.
To systematically assess the improvement of strains, a model is created that links colonization dynamics of the microbial community to genetic activity by key species. The model is used to predict genetic targets for non-intergeneric genetic remodeling (i.e. engineering the genetic architecture of the microbe in a non-transgenic fashion). See,
As illustrated in
To this end, the inventors have developed a platform to identify and improve the role of strains within the crop microbiome. In some aspects, the inventors call this process microbial breeding.
The aforementioned “Guided Microbial Remodeling” process will be further elaborated upon in the Examples, for instance in Example 1, entitled: “Guided Microbial Remodeling—A Platform for the Rational Improvement of Microbial Species for Agriculture.”
Production of bacteria to improve plant traits (e.g., nitrogen fixation) can be achieved through serial passage. The production of these bacteria can be done by selecting plants, which have a particular improved trait that is influenced by the microbial flora, in addition to identifying bacteria and/or compositions that are capable of imparting one or more improved traits to one or more plants. One method of producing a bacteria to improve a plant trait includes the steps of: (a) isolating bacteria from tissue or soil of a first plant; (b) introducing a genetic variation into one or more of the bacteria to produce one or more variant bacteria; (c) exposing a plurality of plants to the variant bacteria; (d) isolating bacteria from tissue or soil of one of the plurality of plants, wherein the plant from which the bacteria is isolated has an improved trait relative to other plants in the plurality of plants; and (e) repeating steps (b) to (d) with bacteria isolated from the plant with an improved trait (step (d)). Steps (b) to (d) can be repeated any number of times (e.g., once, twice, three times, four times, five times, ten times, or more) until the improved trait in a plant reaches a desired level. Further, the plurality of plants can be more than two plants, such as 10 to 20 plants, or 20 or more, 50 or more, 100 or more, 300 or more, 500 or more, or 1000 or more plants.
In addition to obtaining a plant with an improved trait, a bacterial population comprising bacteria comprising one or more genetic variations introduced into one or more genes (e.g., genes regulating nitrogen fixation) is obtained. By repeating the steps described above, a population of bacteria can be obtained that include the most appropriate members of the population that correlate with a plant trait of interest. The bacteria in this population can be identified and their beneficial properties determined, such as by genetic and/or phenotypic analysis. Genetic analysis may occur of isolated bacteria in step (a). Phenotypic and/or genotypic information may be obtained using techniques including: high through-put screening of chemical components of plant origin, sequencing techniques including high throughput sequencing of genetic material, differential display techniques (including DDRT-PCR, and DD-PCR), nucleic acid microarray techniques, RNA-sequencing (Whole Transcriptome Shotgun Sequencing), and qRT-PCR (quantitative real time PCR). Information gained can be used to obtain community profiling information on the identity and activity of bacteria present, such as phylogenetic analysis or microarray-based screening of nucleic acids coding for components of rRNA operons or other taxonomically informative loci. Examples of taxonomically informative loci include 16S rRNA gene, 23S rRNA gene, 5S rRNA gene, 5.8S rRNA gene, 12S rRNA gene, 18S rRNA gene, 28S rRNA gene, gyrB gene, rpoB gene, fusA gene, recA gene, coxl gene, nifD gene. Example processes of taxonomic profiling to determine taxa present in a population are described in US20140155283. Bacterial identification may comprise characterizing activity of one or more genes or one or more signaling pathways, such as genes associated with the nitrogen fixation pathway. Synergistic interactions (where two components, by virtue of their combination, increase a desired effect by more than an additive amount) between different bacterial species may also be present in the bacterial populations.
The genetic variation may be a gene selected from the group consisting of: nifA, nifL, ntrB, ntrC, glnA, glnB, glnK, draT, amtB, glnD, glnE, nifJ, nifH, nifD, nifK, nifY, nifE, nifN, nifU, nifS, nifV, nifW, nifZ, nifM, nifF, nifB, and nifQ. The genetic variation may be a variation in a gene encoding a protein with functionality selected from the group consisting of: glutamine synthetase, glutaminase, glutamine synthetase adenylyltransferase, transcriptional activator, anti-transcriptional activator, pyruvate flavodoxin oxidoreductase, flavodoxin, and NAD+-dinitrogen-reductase aDP-D-ribosyltransferase. The genetic variation may be a mutation that results in one or more of: increased expression or activity of NifA or glutaminase; decreased expression or activity of NifL, NtrB, glutamine synthetase, GlnB, GlnK, DraT, AmtB; decreased adenylyl-removing activity of GlnE; or decreased uridylyl-removing activity of GlnD. The genetic variation may be a variation in a gene selected from the group consisting of: bcsii, bcsiii, yjbE, fhaB, pehA, otsB, treZ, glsA2, and combinations thereof. In some embodiments, a genetic variation may be a variation in any of the genes described throughout this disclosure.
Introducing a genetic variation may comprise insertion and/or deletion of one or more nucleotides at a target site, such as 1, 2, 3, 4, 5, 10, 25, 50, 100, 250, 500, or more nucleotides. The genetic variation introduced into one or more bacteria of the methods disclosed herein may be a knock-out mutation (e.g. deletion of a promoter, insertion or deletion to produce a premature stop codon, deletion of an entire gene), or it may be elimination or abolishment of activity of a protein domain (e.g. point mutation affecting an active site, or deletion of a portion of a gene encoding the relevant portion of the protein product), or it may alter or abolish a regulatory sequence of a target gene. One or more regulatory sequences may also be inserted, including heterologous regulatory sequences and regulatory sequences found within a genome of a bacterial species or genus corresponding to the bacteria into which the genetic variation is introduced. Moreover, regulatory sequences may be selected based on the expression level of a gene in a bacterial culture or within a plant tissue. The genetic variation may be a pre-determined genetic variation that is specifically introduced to a target site. The genetic variation may be a random mutation within the target site. The genetic variation may be an insertion or deletion of one or more nucleotides. In some cases, a plurality of different genetic variations (e.g. 2, 3, 4, 5, 10, or more) are introduced into one or more of the isolated bacteria before exposing the bacteria to plants for assessing trait improvement. The plurality of genetic variations can be any of the above types, the same or different types, and in any combination. In some cases, a plurality of different genetic variations are introduced serially, introducing a first genetic variation after a first isolation step, a second genetic variation after a second isolation step, and so forth so as to accumulate a plurality of genetic variations in bacteria imparting progressively improved traits on the associated plants.
In general, the term “genetic variation” refers to any change introduced into a polynucleotide sequence relative to a reference polynucleotide, such as a reference genome or portion thereof, or reference gene or portion thereof. A genetic variation may be referred to as a “mutation,” and a sequence or organism comprising a genetic variation may be referred to as a “genetic variant” or “mutant”. Genetic variations can have any number of effects, such as the increase or decrease of some biological activity, including gene expression, metabolism, and cell signaling. Genetic variations can be specifically introduced to a target site, or introduced randomly. A variety of molecular tools and methods are available for introducing genetic variation. For example, genetic variation can be introduced via polymerase chain reaction mutagenesis, oligonucleotide-directed mutagenesis, saturation mutagenesis, fragment shuffling mutagenesis, homologous recombination, recombineering, lambda red mediated recombination, CRISPR/Cas9 systems, chemical mutagenesis, and combinations thereof. Chemical methods of introducing genetic variation include exposure of DNA to a chemical mutagen, e.g., ethyl methanesulfonate (EMS), methyl methanesulfonate (MMS), N-nitrosourea (EN U), N-methyl-N-nitro-N′-nitrosoguanidine, 4-nitroquinoline N-oxide, diethylsulfate, benzopyrene, cyclophosphamide, bleomycin, triethylmelamine, acrylamide monomer, nitrogen mustard, vincristine, diepoxyalkanes (for example, diepoxybutane), ICR-170, formaldehyde, procarbazine hydrochloride, ethylene oxide, dimethylnitrosamine, 7,12 dimethylbenz(a)anthracene, chlorambucil, hexamethylphosphoramide, bisulfan, and the like. Radiation mutation-inducing agents include ultraviolet radiation, γ-irradiation, X-rays, and fast neutron bombardment. Genetic variation can also be introduced into a nucleic acid using, e.g., trimethylpsoralen with ultraviolet light. Random or targeted insertion of a mobile DNA element, e.g., a transposable element, is another suitable method for generating genetic variation. Genetic variations can be introduced into a nucleic acid during amplification in a cell-free in vitro system, e.g., using a polymerase chain reaction (PCR) technique such as error-prone PCR. Genetic variations can be introduced into a nucleic acid in vitro using DNA shuffling techniques (e.g., exon shuffling, domain swapping, and the like). Genetic variations can also be introduced into a nucleic acid as a result of a deficiency in a DNA repair enzyme in a cell, e.g., the presence in a cell of a mutant gene encoding a mutant DNA repair enzyme is expected to generate a high frequency of mutations (i.e., about 1 mutation/100 genes-1 mutation/10,000 genes) in the genome of the cell. Examples of genes encoding DNA repair enzymes include but are not limited to Mut H, Mut S, Mut L, and Mut U, and the homologs thereof in other species (e.g., MSH 1 6, PMS 1 2, MLH 1, GTBP, ERCC-1, and the like). Example descriptions of various methods for introducing genetic variations are provided in e.g., Stemple (2004) Nature 5:1-7; Chiang et al. (1993) PCR Methods Appl 2(3): 210-217; Stemmer (1994) Proc. Natl. Acad. Sci. USA 91:10747-10751; and U.S. Pat. Nos. 6,033,861, and 6,773,900.
Genetic variations introduced into microbes may be classified as transgenic, cisgenic, intragenomic, intrageneric, intergeneric, synthetic, evolved, rearranged, or SNPs.
Genetic variation may be introduced into numerous metabolic pathways within microbes to elicit improvements in the traits described above. Representative pathways include sulfur uptake pathways, glycogen biosynthesis, the glutamine regulation pathway, the molybdenum uptake pathway, the nitrogen fixation pathway, ammonia assimilation, ammonia excretion or secretion, Nitrogen uptake, glutamine biosynthesis, colonization pathways, annamox, phosphate solubilization, organic acid transport, organic acid production, agglutinins production, reactive oxygen radical scavenging genes, Indole Acetic Acid biosynthesis, trehalose biosynthesis, plant cell wall degrading enzymes or pathways, root attachment genes, exopolysaccharide secretion, glutamate synthase pathway, iron uptake pathways, siderophore pathway, chitinase pathway, ACC deaminase, glutathione biosynthesis, phosphorous signaling genes, quorum quenching pathway, cytochrome pathways, hemoglobin pathway, bacterial hemoglobin-like pathway, small RNA rsmZ, rhizobitoxine biosynthesis, lapA adhesion protein, AHL quorum sensing pathway, phenazine biosynthesis, cyclic lipopeptide biosynthesis, and antibiotic production.
CRISPR/Cas9 (Clustered regularly interspaced short palindromic repeats)/CRISPR-associated (Cas) systems can be used to introduce desired mutations. CRISPR/Cas9 provide bacteria and archaea with adaptive immunity against viruses and plasmids by using CRISPR RNAs (crRNAs) to guide the silencing of invading nucleic acids. The Cas9 protein (or functional equivalent and/or variant thereof, i.e., Cas9-like protein) naturally contains DNA endonuclease activity that depends on the association of the protein with two naturally occurring or synthetic RNA molecules called crRNA and tracrRNA (also called guide RNAs). In some cases, the two molecules are covalently link to form a single molecule (also called a single guide RNA (“sgRNA”). Thus, the Cas9 or Cas9-like protein associates with a DNA-targeting RNA (which term encompasses both the two-molecule guide RNA configuration and the single-molecule guide RNA configuration), which activates the Cas9 or Cas9-like protein and guides the protein to a target nucleic acid sequence. If the Cas9 or Cas9-like protein retains its natural enzymatic function, it will cleave target DNA to create a double-stranded break, which can lead to genome alteration (i.e., editing: deletion, insertion (when a donor polynucleotide is present), replacement, etc.), thereby altering gene expression. Some variants of Cas9 (which variants are encompassed by the term Cas9-like) have been altered such that they have a decreased DNA cleaving activity (in some cases, they cleave a single strand instead of both strands of the target DNA, while in other cases, they have severely reduced to no DNA cleavage activity). Further exemplary descriptions of CRISPR systems for introducing genetic variation can be found in, e.g. U.S. Pat. No. 8,795,965.
As a cyclic amplification technique, polymerase chain reaction (PCR) mutagenesis uses mutagenic primers to introduce desired mutations. PCR is performed by cycles of denaturation, annealing, and extension. After amplification by PCR, selection of mutated DNA and removal of parental plasmid DNA can be accomplished by: 1) replacement of dCTP by hydroxymethylated-dCTP during PCR, followed by digestion with restriction enzymes to remove non-hydroxymethylated parent DNA only; 2) simultaneous mutagenesis of both an antibiotic resistance gene and the studied gene changing the plasmid to a different antibiotic resistance, the new antibiotic resistance facilitating the selection of the desired mutation thereafter; 3) after introducing a desired mutation, digestion of the parent methylated template DNA by restriction enzyme Dpnl which cleaves only methylated DNA, by which the mutagenized unmethylated chains are recovered; or 4) circularization of the mutated PCR products in an additional ligation reaction to increase the transformation efficiency of mutated DNA. Further description of exemplary methods can be found in e.g. U.S. Pat. Nos. 7,132,265, 6,713,285, 6,673,610, 6,391,548, 5,789,166, 5,780,270, 5,354,670, 5,071,743, and US20100267147.
Oligonucleotide-directed mutagenesis, also called site-directed mutagenesis, typically utilizes a synthetic DNA primer. This synthetic primer contains the desired mutation and is complementary to the template DNA around the mutation site so that it can hybridize with the DNA in the gene of interest. The mutation may be a single base change (a point mutation), multiple base changes, deletion, or insertion, or a combination of these. The single-strand primer is then extended using a DNA polymerase, which copies the rest of the gene. The gene thus copied contains the mutated site, and may then be introduced into a host cell as a vector and cloned. Finally, mutants can be selected by DNA sequencing to check that they contain the desired mutation.
Genetic variations can be introduced using error-prone PCR. In this technique the gene of interest is amplified using a DNA polymerase under conditions that are deficient in the fidelity of replication of sequence. The result is that the amplification products contain at least one error in the sequence. When a gene is amplified and the resulting product(s) of the reaction contain one or more alterations in sequence when compared to the template molecule, the resulting products are mutagenized as compared to the template. Another means of introducing random mutations is exposing cells to a chemical mutagen, such as nitrosoguanidine or ethyl methanesulfonate (Nestmann, Mutat Res 1975 June; 28(3):323-30), and the vector containing the gene is then isolated from the host.
Saturation mutagenesis is another form of random mutagenesis, in which one tries to generate all or nearly all possible mutations at a specific site, or narrow region of a gene. In a general sense, saturation mutagenesis is comprised of mutagenizing a complete set of mutagenic cassettes (wherein each cassette is, for example, 1-500 bases in length) in defined polynucleotide sequence to be mutagenized (wherein the sequence to be mutagenized is, for example, from 15 to 100,000 bases in length). Therefore, a group of mutations (e.g. ranging from 1 to 100 mutations) is introduced into each cassette to be mutagenized. A grouping of mutations to be introduced into one cassette can be different or the same from a second grouping of mutations to be introduced into a second cassette during the application of one round of saturation mutagenesis. Such groupings are exemplified by deletions, additions, groupings of particular codons, and groupings of particular nucleotide cassettes.
Fragment shuffling mutagenesis, also called DNA shuffling, is a way to rapidly propagate beneficial mutations. In an example of a shuffling process, DNAse is used to fragment a set of parent genes into pieces of e.g. about 50-100 bp in length. This is then followed by a polymerase chain reaction (PCR) without primers—DNA fragments with sufficient overlapping homologous sequence will anneal to each other and are then be extended by DNA polymerase. Several rounds of this PCR extension are allowed to occur, after some of the DNA molecules reach the size of the parental genes. These genes can then be amplified with another PCR, this time with the addition of primers that are designed to complement the ends of the strands. The primers may have additional sequences added to their 5′ ends, such as sequences for restriction enzyme recognition sites needed for ligation into a cloning vector. Further examples of shuffling techniques are provided in US20050266541.
Homologous recombination mutagenesis involves recombination between an exogenous DNA fragment and the targeted polynucleotide sequence. After a double-stranded break occurs, sections of DNA around the 5′ ends of the break are cut away in a process called resection. In the strand invasion step that follows, an overhanging 3′ end of the broken DNA molecule then “invades” a similar or identical DNA molecule that is not broken. The method can be used to delete a gene, remove exons, add a gene, and introduce point mutations. Homologous recombination mutagenesis can be permanent or conditional. Typically, a recombination template is also provided. A recombination template may be a component of another vector, contained in a separate vector, or provided as a separate polynucleotide. In some embodiments, a recombination template is designed to serve as a template in homologous recombination, such as within or near a target sequence nicked or cleaved by a site-specific nuclease. A template polynucleotide may be of any suitable length, such as about or more than about 10, 15, 20, 25, 50, 75, 100, 150, 200, 500, 1000, or more nucleotides in length. In some embodiments, the template polynucleotide is complementary to a portion of a polynucleotide comprising the target sequence. When optimally aligned, a template polynucleotide might overlap with one or more nucleotides of a target sequences (e.g. about or more than about 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100 or more nucleotides). In some embodiments, when a template sequence and a polynucleotide comprising a target sequence are optimally aligned, the nearest nucleotide of the template polynucleotide is within about 1, 5, 10, 15, 20, 25, 50, 75, 100, 200, 300, 400, 500, 1000, 5000, 10000, or more nucleotides from the target sequence. Non-limiting examples of site-directed nucleases useful in methods of homologous recombination include zinc finger nucleases, CRISPR nucleases, TALE nucleases, and meganuclease. For a further description of the use of such nucleases, see e.g. U.S. Pat. No. 8,795,965 and US20140301990.
Mutagens that create primarily point mutations and short deletions, insertions, transversions, and/or transitions, including chemical mutagens or radiation, may be used to create genetic variations. Mutagens include, but are not limited to, ethyl methanesulfonate, methylmethane sulfonate, N-ethyl-N-nitrosurea, triethylmelamine, N-methyl-N-nitrosourea, procarbazine, chlorambucil, cyclophosphamide, diethyl sulfate, acrylamide monomer, melphalan, nitrogen mustard, vincristine, dimethylnitrosamine, N-methyl-N′-nitro-Nitrosoguanidine, nitrosoguanidine, 2-aminopurine, 7,12 dimethyl-benz(a)anthracene, ethylene oxide, hexamethylphosphoramide, bisulfan, diepoxyalkanes (diepoxyoctane, diepoxybutane, and the like), 2-methoxy-6-chloro-9 [3-(ethyl-2-chloro-ethyl)aminopropylamino]acridine dihydrochloride and formaldehyde.
Introducing genetic variation may be an incomplete process, such that some bacteria in a treated population of bacteria carry a desired mutation while others do not. In some cases, it is desirable to apply a selection pressure so as to enrich for bacteria carrying a desired genetic variation. Traditionally, selection for successful genetic variants involved selection for or against some functionality imparted or abolished by the genetic variation, such as in the case of inserting antibiotic resistance gene or abolishing a metabolic activity capable of converting a non-lethal compound into a lethal metabolite. It is also possible to apply a selection pressure based on a polynucleotide sequence itself, such that only a desired genetic variation need be introduced (e.g. without also requiring a selectable marker). In this case, the selection pressure can comprise cleaving genomes lacking the genetic variation introduced to a target site, such that selection is effectively directed against the reference sequence into which the genetic variation is sought to be introduced. Typically, cleavage occurs within 100 nucleotides of the target site (e.g. within 75, 50, 25, 10, or fewer nucleotides from the target site, including cleavage at or within the target site). Cleaving may be directed by a site-specific nuclease selected from the group consisting of a Zinc Finger nuclease, a CRISPR nuclease, a TALE nuclease (TALEN), and a meganuclease. Such a process is similar to processes for enhancing homologous recombination at a target site, except that no template for homologous recombination is provided. As a result, bacteria lacking the desired genetic variation are more likely to undergo cleavage that, left unrepaired, results in cell death. Bacteria surviving selection may then be isolated for use in exposing to plants for assessing conferral of an improved trait.
A CRISPR nuclease may be used as the site-specific nuclease to direct cleavage to a target site. An improved selection of mutated microbes can be obtained by using Cas9 to kill non-mutated cells. Plants are then inoculated with the mutated microbes to re-confirm symbiosis and create evolutionary pressure to select for efficient symbionts. Microbes can then be re-isolated from plant tissues. CRISPR nuclease systems employed for selection against non-variants can employ similar elements to those described above with respect to introducing genetic variation, except that no template for homologous recombination is provided. Cleavage directed to the target site thus enhances death of affected cells.
Other options for specifically inducing cleavage at a target site are available, such as zinc finger nucleases, TALE nuclease (TALEN) systems, and meganuclease. Zinc-finger nucleases (ZFNs) are artificial DNA endonucleases generated by fusing a zinc finger DNA binding domain to a DNA cleavage domain. ZFNs can be engineered to target desired DNA sequences and this enables zinc-finger nucleases to cleave unique target sequences. When introduced into a cell, ZFNs can be used to edit target DNA in the cell (e.g., the cell's genome) by inducing double stranded breaks. Transcription activator-like effector nucleases (TALENs) are artificial DNA endonucleases generated by fusing a TAL (Transcription activator-like) effector DNA binding domain to a DNA cleavage domain. TALENS can be quickly engineered to bind practically any desired DNA sequence and when introduced into a cell, TALENs can be used to edit target DNA in the cell (e.g., the cell's genome) by inducing double strand breaks. Meganucleases (homing endonuclease) are endodeoxyribonucleases characterized by a large recognition site (double-stranded DNA sequences of 12 to 40 base pairs. Meganucleases can be used to replace, eliminate or modify sequences in a highly targeted way. By modifying their recognition sequence through protein engineering, the targeted sequence can be changed. Meganucleases can be used to modify all genome types, whether bacterial, plant or animal and are commonly grouped into four families: the LAGLIDADG family (SEQ ID NO: 1), the GIY-YIG family, the His-Cyst box family and the HNH family. Exemplary homing endonucleases include I-SceI, I-CeuI, PI-PspI, PI-Sce, I-SceIV, I-Csml, I-PanI, I-SceII, I-PpoI, I-SceIII, I-CreI, I-TevI, I-TevII and I-TevIII.
The microbes of the present disclosure may be identified by one or more genetic modifications or alterations, which have been introduced into said microbe. One method by which said genetic modification or alteration can be identified is via reference to a SEQ ID NO that contains a portion of the microbe's genomic sequence that is sufficient to identify the genetic modification or alteration.
Further, in the case of microbes that have not had a genetic modification or alteration (e.g. a wild type, WT) introduced into their genomes, the disclosure can utilize 16S nucleic acid sequences to identify said microbes. A 16S nucleic acid sequence is an example of a “molecular marker” or “genetic marker,” which refers to an indicator that is used in methods for visualizing differences in characteristics of nucleic acid sequences. Examples of other such indicators are restriction fragment length polymorphism (RFLP) markers, amplified fragment length polymorphism (AFLP) markers, single nucleotide polymorphisms (SNPs), insertion mutations, microsatellite markers (SSRs), sequence-characterized amplified regions (SCARs), cleaved amplified polymorphic sequence (CAPS) markers or isozyme markers or combinations of the markers described herein which defines a specific genetic and chromosomal location. Markers further include polynucleotide sequences encoding 16S or 18S rRNA, and internal transcribed spacer (ITS) sequences, which are sequences found between small-subunit and large-subunit rRNA genes that have proven to be especially useful in elucidating relationships or distinctions when compared against one another. Furthermore, the disclosure utilizes unique sequences found in genes of interest (e.g. nif H,D,K,L,A, glnE, amtB, etc.) to identify microbes disclosed herein.
The primary structure of major rRNA subunit 16S comprise a particular combination of conserved, variable, and hypervariable regions that evolve at different rates and enable the resolution of both very ancient lineages such as domains, and more modern lineages such as genera. The secondary structure of the 16S subunit include approximately 50 helices which result in base pairing of about 67% of the residues. These highly conserved secondary structural features are of great functional importance and can be used to ensure positional homology in multiple sequence alignments and phylogenetic analysis. Over the previous few decades, the 16S rRNA gene has become the most sequenced taxonomic marker and is the cornerstone for the current systematic classification of bacteria and archaea (Yarza et al. 2014. Nature Rev. Micro. 12:635-45).
Thus, in certain aspects, the disclosure provides for a sequence, which shares at least about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to any sequence in Tables 23, 24, 30, 31, and 32.
Thus, in certain aspects, the disclosure provides for a microbe that comprises a sequence, which shares at least about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NOs: 62-303. These sequences and their associated descriptions can be found in Tables 31 and 32.
In some aspects, the disclosure provides for a microbe that comprises a 16S nucleic acid sequence, which shares at least about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NOs: 85, 96, 111, 121, 122, 123, 124, 136, 149, 157, 167, 261, 262, 269, 277-283. These sequences and their associated descriptions can be found in Table 32.
In some aspects, the disclosure provides for a microbe that comprises a nucleic acid sequence, which shares at least about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NOs: 86-95, 97-110, 112-120, 125-135, 137-148, 150-156, 158-166, 168-176, 263-268, 270-274, 275, 276, 284-295. These sequences and their associated descriptions can be found in Table 32.
In some aspects, the disclosure provides for a microbe that comprises a nucleic acid sequence, which shares at least about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NOs: 177-260, 296-303. These sequences and their associated descriptions can be found in Table 32.
In some aspects, the disclosure provides for a microbe that comprises, or primer that comprises, or probe that comprises, or non-native junction sequence that comprises, a nucleic acid sequence, which shares at least about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NOs: 304-424. These sequences and their associated descriptions can be found in Table 30.
In some aspects, the disclosure provides for a microbe that comprises a non-native junction sequence that shares at least about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NOs: 372-405. These sequences and their associated descriptions can be found in Table 30.
In some aspects, the disclosure provides for a microbe that comprises an amino acid sequence, which shares at least about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to SEQ ID NOs: 77, 78, 81, 82, or 83. These sequences and their associated descriptions can be found in Table 31.
The present disclosure teaches primers, probes, and assays that are useful for detecting the microbes taught herein. In some aspects, the disclosure provides for methods of detecting the WT parental strains. In other aspects, the disclosure provides for methods of detecting the non-intergeneric engineered microbes derived from the WT strains. In aspects, the present disclosure provides methods of identifying non-intergeneric genetic alterations in a microbe.
In aspects, the genomic engineering methods of the present disclosure lead to the creation of non-natural nucleotide “junction” sequences in the derived non-intergeneric microbes. These non-naturally occurring nucleotide junctions can be used as a type of diagnostic that is indicative of the presence of a particular genetic alteration in a microbe taught herein.
The present techniques are able to detect these non-naturally occurring nucleotide junctions via the utilization of specialized quantitative PCR methods, including uniquely designed primers and probes. In some aspects, the probes of the disclosure bind to the non-naturally occurring nucleotide junction sequences. In some aspects, traditional PCR is utilized. In other aspects, real-time PCR is utilized. In some aspects, quantitative PCR (qPCR) is utilized.
Thus, the disclosure can cover the utilization of two common methods for the detection of PCR products in real-time: (1) non-specific fluorescent dyes that intercalate with any double-stranded DNA, and (2) sequence-specific DNA probes consisting of oligonucleotides that are labelled with a fluorescent reporter which permits detection only after hybridization of the probe with its complementary sequence. In some aspects, only the non-naturally occurring nucleotide junction will be amplified via the taught primers, and consequently can be detected either via a non-specific dye, or via the utilization of a specific hybridization probe. In other aspects, the primers of the disclosure are chosen such that the primers flank either side of a junction sequence, such that if an amplification reaction occurs, then said junction sequence is present.
Aspects of the disclosure involve non-naturally occurring nucleotide junction sequence molecules per se, along with other nucleotide molecules that are capable of binding to said non-naturally occurring nucleotide junction sequences under mild to stringent hybridization conditions. In some aspects, the nucleotide molecules that are capable of binding to said non-naturally occurring nucleotide junction sequences under mild to stringent hybridization conditions are termed “nucleotide probes.”
In aspects, genomic DNA can be extracted from samples and used to quantify the presence of microbes of the disclosure by using qPCR. The primers utilized in the qPCR reaction can be primers designed by Primer Blast (www.ncbi.nlm.nih.gov/tools/primer-blast/) to amplify unique regions of the wild-type genome or unique regions of the engineered non-intergeneric mutant strains. The qPCR reaction can be carried out using the SYBR GreenER qPCR SuperMix Universal (Thermo Fisher P/N 11762100) kit, using only forward and reverse amplification primers; alternatively, the Kapa Probe Force kit (Kapa Biosystems P/N KK4301) can be used with amplification primers and a TaqMan probe containing a FAM dye label at the 5′ end, an internal ZEN quencher, and a minor groove binder and fluorescent quencher at the 3′ end (Integrated DNA Technologies).
Certain primer, probe, and non-native junction sequences are listed in Table 30. qPCR reaction efficiency can be measured using a standard curve generated from a known quantity of gDNA from the target genome. Data can be normalized to genome copies per g fresh weight using the tissue weight and extraction volume.
Quantitative polymerase chain reaction (qPCR) is a method of quantifying, in real time, the amplification of one or more nucleic acid sequences. The real time quantification of the PCR assay permits determination of the quantity of nucleic acids being generated by the PCR amplification steps by comparing the amplifying nucleic acids of interest and an appropriate control nucleic acid sequence, which may act as a calibration standard.
TaqMan probes are often utilized in qPCR assays that require an increased specificity for quantifying target nucleic acid sequences. TaqMan probes comprise a oligonucleotide probe with a fluorophore attached to the 5′ end and a quencher attached to the 3′ end of the probe. When the TaqMan probes remain as is with the 5′ and 3′ ends of the probe in close contact with each other, the quencher prevents fluorescent signal transmission from the fluorophore. TaqMan probes are designed to anneal within a nucleic acid region amplified by a specific set of primers. As the Taq polymerase extends the primer and synthesizes the nascent strand, the 5′ to 3′ exonuclease activity of the Taq polymerase degrades the probe that annealed to the template. This probe degradation releases the fluorophore, thus breaking the close proximity to the quencher and allowing fluorescence of the fluorophore. Fluorescence detected in the qPCR assay is directly proportional to the fluorophore released and the amount of DNA template present in the reaction.
The features of qPCR allow the practitioner to eliminate the labor-intensive post-amplification step of gel electrophoresis preparation, which is generally required for observation of the amplified products of traditional PCR assays. The benefits of qPCR over conventional PCR are considerable, and include increased speed, ease of use, reproducibility, and quantitative ability.
Methods of the present disclosure may be employed to introduce or improve one or more of a variety of desirable traits. Examples of traits that may introduced or improved include: root biomass, root length, height, shoot length, leaf number, water use efficiency, overall biomass, yield, fruit size, grain size, photosynthesis rate, tolerance to drought, heat tolerance, salt tolerance, resistance to nematode stress, resistance to a fungal pathogen, resistance to a bacterial pathogen, resistance to a viral pathogen, level of a metabolite, and proteome expression. The desirable traits, including height, overall biomass, root and/or shoot biomass, seed germination, seedling survival, photosynthetic efficiency, transpiration rate, seed/fruit number or mass, plant grain or fruit yield, leaf chlorophyll content, photosynthetic rate, root length, or any combination thereof, can be used to measure growth, and compared with the growth rate of reference agricultural plants (e.g., plants without the improved traits) grown under identical conditions.
A preferred trait to be introduced or improved is nitrogen fixation, as described herein. A second preferred trait to be introduced or improved is colonization potential, as described herein. In some cases, a plant resulting from the methods described herein exhibits a difference in the trait that is at least about 5% greater, for example at least about 5%, at least about 8%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 75%, at least about 80%, at least about 80%, at least about 90%, or at least 100%, at least about 200%, at least about 300%, at least about 400% or greater than a reference agricultural plant grown under the same conditions in the soil. In additional examples, a plant resulting from the methods described herein exhibits a difference in the trait that is at least about 5% greater, for example at least about 5%, at least about 8%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 75%, at least about 80%, at least about 80%, at least about 90%, or at least 100%, at least about 200%, at least about 300%, at least about 400% or greater than a reference agricultural plant grown under similar conditions in the soil.
The trait to be improved may be assessed under conditions including the application of one or more biotic or abiotic stressors. Examples of stressors include abiotic stresses (such as heat stress, salt stress, drought stress, cold stress, and low nutrient stress) and biotic stresses (such as nematode stress, insect herbivory stress, fungal pathogen stress, bacterial pathogen stress, and viral pathogen stress).
The trait improved by methods and compositions of the present disclosure may be nitrogen fixation, including in a plant not previously capable of nitrogen fixation. In some cases, bacteria isolated according to a method described herein produce 1% or more (e.g. 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, or more) of a plant's nitrogen, which may represent an increase in nitrogen fixation capability of at least 2-fold (e.g. 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 20-fold, 50-fold, 100-fold, 1000-fold, or more) as compared to bacteria isolated from the first plant before introducing any genetic variation. In some cases, the bacteria produce 5% or more of a plant's nitrogen. The desired level of nitrogen fixation may be achieved after repeating the steps of introducing genetic variation, exposure to a plurality of plants, and isolating bacteria from plants with an improved trait one or more times (e.g. 1, 2, 3, 4, 5, 10, 15, 25, or more times). In some cases, enhanced levels of nitrogen fixation are achieved in the presence of fertilizer supplemented with glutamine, ammonia, or other chemical source of nitrogen. Methods for assessing degree of nitrogen fixation are known, examples of which are described herein.
Microbe breeding is a method to systematically identify and improve the role of species within the crop microbiome. The method comprises three steps: 1) selection of candidate species by mapping plant-microbe interactions and predicting regulatory networks linked to a particular phenotype, 2) pragmatic and predictable improvement of microbial phenotypes through intra-species crossing of regulatory networks and gene clusters, and 3) screening and selection of new microbial genotypes that produce desired crop phenotypes. To systematically assess the improvement of strains, a model is created that links colonization dynamics of the microbial community to genetic activity by key species. The model is used to predict genetic targets for breeding and improve the frequency of selecting improvements in microbiome-encoded traits of agronomic relevance.
In the field, the amount of nitrogen delivered can be determined by the function of colonization multiplied by the activity.
The above equation requires (1) the average colonization per unit of plant tissue, and (2) the activity as either the amount of nitrogen fixed or the amount of ammonia excreted by each microbial cell. To convert to pounds of nitrogen per acre, corn growth physiology is tracked over time, e.g., size of the plant and associated root system throughout the maturity stages.
The pounds of nitrogen delivered to a crop per acre-season can be calculated by the following equation:
Nitrogen delivered=∫Plant Tissue(t)×Colonization(t)×Activity(t)dt
The Plant Tissue(t) is the fresh weight of corn plant tissue over the growing time (t). Values for reasonably making the calculation are described in detail in the publication entitled Roots, Growth and Nutrient Uptake (Mengel. Dept. of Agronomy Pub.#AGRY-95-08 (Rev. May-95. p. 1-8.).
The Colonization (t) is the amount of the microbes of interest found within the plant tissue, per gram fresh weight of plant tissue, at any particular time, t, during the growing season. In the instance of only a single timepoint available, the single timepoint is normalized as the peak colonization rate over the season, and the colonization rate of the remaining timepoints are adjusted accordingly.
Activity(t) is the rate of which N is fixed by the microbes of interest per unit time, at any particular time, t, during the growing season. In the embodiments disclosed herein, this activity rate is approximated by in vitro acetylene reduction assay (ARA) in ARA media in the presence of 5 mM glutamine or Ammonium excretion assay in ARA media in the presence of 5 mM ammonium ions.
The Nitrogen delivered amount is then calculated by numerically integrating the above function. In cases where the values of the variables described above are discretely measured at set timepoints, the values in between those timepoints are approximated by performing linear interpolation.
Described herein are methods of increasing nitrogen fixation in a plant, comprising exposing the plant to bacteria comprising one or more genetic variations introduced into one or more genes regulating nitrogen fixation, wherein the bacteria produce 1% or more of nitrogen in the plant (e.g. 2%, 5%, 10%, or more), which may represent a nitrogen-fixation capability of at least 2-fold as compared to the plant in the absence of the bacteria. The bacteria may produce the nitrogen in the presence of fertilizer supplemented with glutamine, urea, nitrates or ammonia. Genetic variations can be any genetic variation described herein, including examples provided above, in any number and any combination. The genetic variation may be introduced into a gene selected from the group consisting of nifA, nifL, ntrB, ntrC, glutamine synthetase, glnA, glnB, glnK, draT, amtB, glutaminase, glnD, glnE, nifJ, nifH, nifD, nifK, nifY, nifE, nifN, nifU, nifS, nifV, nifW, nifZ, nifM, nifF, nifB, and nifQ. The genetic variation may be a mutation that results in one or more of: increased expression or activity of nifA or glutaminase; decreased expression or activity of nifL, ntrB, glutamine synthetase, glnB, glnK, draT, amtB; decreased adenylyl-removing activity of GlnE; or decreased uridylyl-removing activity of GlnD. The genetic variation introduced into one or more bacteria of the methods disclosed herein may be a knock-out mutation or it may abolish a regulatory sequence of a target gene, or it may comprise insertion of a heterologous regulatory sequence, for example, insertion of a regulatory sequence found within the genome of the same bacterial species or genus. The regulatory sequence can be chosen based on the expression level of a gene in a bacterial culture or within plant tissue. The genetic variation may be produced by chemical mutagenesis. The plants grown in step (c) may be exposed to biotic or abiotic stressors.
In some embodiments, non-intergeneric remodeled bacteria of the present disclosure each produce fixed N of at least about 2×10−13 mmol of N per CFU per hour, about 2.5×10−13 mmol of N per CFU per hour, about 3×10−13 mmol of N per CFU per hour, about 3.5×10−13 mmol of N per CFU per hour, about 4×10−13 mmol of N per CFU per hour, about 4.5×10−13 mmol of N per CFU per hour, about 5×10−13 mmol of N per CFU per hour, about 5.5×10−13 mmol of N per CFU per hour, about 6×10−13 mmol of N per CFU per hour, about 6.5×10−13 mmol of N per CFU per hour, about 7×10−13 mmol of N per CFU per hour, about 7.5×10−13 mmol of N per CFU per hour, about 8×10−13 mmol of N per CFU per hour, about 8.5×10−13 mmol of N per CFU per hour, about 9×10−13 mmol of N per CFU per hour, about 9.5×10−13 mmol of N per CFU per hour, or about 10×10−13 mmol of N per CFU per hour.
In some embodiments, non-intergeneric remodeled bacteria of the present disclosure each produce fixed N of at least about 2×10−12 mmol of N per CFU per hour, about 2.25×10−12 mmol of N per CFU per hour, about 2.5×10−12 mmol of N per CFU per hour, about 2.75×10−12 mmol of N per CFU per hour, about 3×10−12 mmol of N per CFU per hour, about 3.25×10−12 mmol of N per CFU per hour, about 3.5×10−12 mmol of N per CFU per hour, about 3.75×10−12 mmol of N per CFU per hour, about 4×10−12 mmol of N per CFU per hour, about 4.25×10−12 mmol of N per CFU per hour, about 4.5×10−12 mmol of N per CFU per hour, about 4.75×10−12 mmol of N per CFU per hour, about 5×10−12 mmol of N per CFU per hour, about 5.25×10−12 mmol of N per CFU per hour, about 5.5×10−12 mmol of N per CFU per hour, about 5.75×10−12 mmol of N per CFU per hour, about 6×10−12 mmol of N per CFU per hour, about 6.25×10−12 mmol of N per CFU per hour, about 6.5×10−12 mmol of N per CFU per hour, about 6.75×10−12 mmol of N per CFU per hour, about 7×10−12 mmol of N per CFU per hour, about 7.25×10−12 mmol of N per CFU per hour, about 7.5×10−12 mmol of N per CFU per hour, about 7.75×10−12 mmol of N per CFU per hour, about 8×10−12 mmol of N per CFU per hour, about 8.25×10−12 mmol of N per CFU per hour, about 8.5×10−12 mmol of N per CFU per hour, about 8.75×10−12 mmol of N per CFU per hour, about 9×10−12 mmol of N per CFU per hour, about 9.25×10−12 mmol of N per CFU per hour, about 9.5×10−12 mmol of N per CFU per hour, about 9.75×10−12 mmol of N per CFU per hour, or about 10×10−12 mmol of N per CFU per hour.
In some embodiments, non-intergeneric remodeled bacteria of the present disclosure each produce fixed N of at least about 5.49×10−13 mmol of N per CFU per hour. In some embodiments, non-intergeneric remodeled bacteria of the present disclosure produce fixed N of at least about 4.03×10−13 mmol of N per CFU per hour. In some embodiments, non-intergeneric remodeled bacteria of the present disclosure produce fixed N of at least about 2.75×10−12 mmol of N per CFU per hour.
In some embodiments, non-intergeneric remodeled bacteria of the present disclosure in aggregate produce at least about 15 pounds of fixed N per acre, at least about 20 pounds of fixed N per acre, at least about 25 pounds of fixed N per acre, at least about 30 pounds of fixed N per acre, at least about 35 pounds of fixed N per acre, at least about 40 pounds of fixed N per acre, at least about 45 pounds of fixed N per acre, at least about 50 pounds of fixed N per acre, at least about 55 pounds of fixed N per acre, at least about 60 pounds of fixed N per acre, at least about 65 pounds of fixed N per acre, at least about 70 pounds of fixed N per acre, at least about 75 pounds of fixed N per acre, at least about 80 pounds of fixed N per acre, at least about 85 pounds of fixed N per acre, at least about 90 pounds of fixed N per acre, at least about 95 pounds of fixed N per acre, or at least about 100 pounds of fixed N per acre.
In some embodiments, non-intergeneric remodeled bacteria of the present disclosure produce fixed N in the amounts disclosed herein over the course of at least about day 0 to about 80 days, at least about day 0 to about 70 days, at least about day 0 to about 60 days, at least about 1 day to about 80 days, at least about 1 day to about 70 days, at least about 1 day to about 60 days, at least about 2 days to about 80 days, at least about 2 days to about 70 days, at least about 2 days to about 60 days, at least about 3 days to about 80 days, at least about 3 days to about 70 days, at least about 3 days to about 60 days, at least about 4 days to about 80 days, at least about 4 days to about 70 days, at least about 4 days to about 60 days, at least about 5 days to about 80 days, at least about 5 days to about 70 days, at least about 5 days to about 60 days, at least about 6 days to about 80 days, at least about 6 days to about 70 days, at least about 6 days to about 60 days, at least about 7 days to about 80 days, at least about 7 days to about 70 days, at least about 7 days to about 60 days, at least about 8 days to about 80 days, at least about 8 days to about 70 days, at least about 8 days to about 60 days, at least about 9 days to about 80 days, at least about 9 days to about 70 days, at least about 9 days to about 60 days, at least about 10 days to about 80 days, at least about 10 days to about 70 days, at least about 10 days to about 60 days, at least about 15 days to about 80 days, at least about 15 days to about 70 days, at least about 15 days to about 60 days, at least about 20 days to about 80 days, at least about 20 days to about 70 days, or at least about 20 days to about 60 days.
In some embodiments, non-intergeneric remodeled bacteria of the present disclosure produce fixed N in any of the amounts disclosed herein over the course of at least about 80 days±5 days, at least about 80 days±10 days, at least about 80 days±15 days, at least about 80 days±20 days, at least about 75 days±5 days, at least about 75 days±10 days, at least about 75 days±15 days, at least about 75 days±20 days, at least about 70 days±5 days, at least about 70 days±10 days, at least about 70 days±15 days, at least about 70 days±20 days, at least about 60 days±5 days, at least about 60 days±10 days, at least about 60 days±15 days, at least about 60 days±20 days.
In some embodiments, non-intergeneric remodeled bacteria of the present disclosure produce fixed N in any of the amounts disclosed herein over the course of at least about 10 days to about 80 days, at least about 10 days to about 70 days, or at least about 10 days to about 60 days.
In some embodiments, non-intergeneric remodeled bacteria of the present disclosure produce fixed N in the amounts and time shown in
The amount of nitrogen fixation that occurs in the plants described herein may be measured in several ways, for example by an acetylene-reduction (AR) assay. An acetylene-reduction assay can be performed in vitro or in vivo. Evidence that a particular bacterium is providing fixed nitrogen to a plant can include: 1) total plant N significantly increases upon inoculation, preferably with a concomitant increase in N concentration in the plant; 2) nitrogen deficiency symptoms are relieved under N-limiting conditions upon inoculation (which should include an increase in dry matter); 3) N2 fixation is documented through the use of an 15N approach (which can be isotope dilution experiments, 15N2 reduction assays, or 15N natural abundance assays); 4) fixed N is incorporated into a plant protein or metabolite; and 5) all of these effects are not be seen in non-inoculated plants or in plants inoculated with a mutant of the inoculum strain.
The wild-type nitrogen fixation regulatory cascade can be represented as a digital logic circuit where the inputs O2 and NH4+ pass through a NOR gate, the output of which enters an AND gate in addition to ATP. In some embodiments, the methods disclosed herein disrupt the influence of NH4+ on this circuit, at multiple points in the regulatory cascade, so that microbes can produce nitrogen even in fertilized fields. However, the methods disclosed herein also envision altering the impact of ATP or O2 on the circuitry, or replacing the circuitry with other regulatory cascades in the cell, or altering genetic circuits other than nitrogen fixation. Gene clusters can be re-engineered to generate functional products under the control of a heterologous regulatory system. By eliminating native regulatory elements outside of, and within, coding sequences of gene clusters, and replacing them with alternative regulatory systems, the functional products of complex genetic operons and other gene clusters can be controlled and/or moved to heterologous cells, including cells of different species other than the species from which the native genes were derived. Once re-engineered, the synthetic gene clusters can be controlled by genetic circuits or other inducible regulatory systems, thereby controlling the products' expression as desired. The expression cassettes can be designed to act as logic gates, pulse generators, oscillators, switches, or memory devices. The controlling expression cassette can be linked to a promoter such that the expression cassette functions as an environmental sensor, such as an oxygen, temperature, touch, osmotic stress, membrane stress, or redox sensor.
As an example, the nifL, nifA, nifT, and nifX genes can be eliminated from the nif gene cluster. Synthetic genes can be designed by codon randomizing the DNA encoding each amino acid sequence. Codon selection is performed, specifying that codon usage be as divergent as possible from the codon usage in the native gene. Proposed sequences are scanned for any undesired features, such as restriction enzyme recognition sites, transposon recognition sites, repetitive sequences, sigma 54 and sigma 70 promoters, cryptic ribosome binding sites, and rho independent terminators. Synthetic ribosome binding sites are chosen to match the strength of each corresponding native ribosome binding site, such as by constructing a fluorescent reporter plasmid in which the 150 bp surrounding a gene's start codon (from −60 to +90) is fused to a fluorescent gene. This chimera can be expressed under control of the Ptac promoter, and fluorescence measured via flow cytometry. To generate synthetic ribosome binding sites, a library of reporter plasmids using 150 bp (−60 to +90) of a synthetic expression cassette is generated. Briefly, a synthetic expression cassette can consist of a random DNA spacer, a degenerate sequence encoding an RBS library, and the coding sequence for each synthetic gene. Multiple clones are screened to identify the synthetic ribosome binding site that best matched the native ribosome binding site. Synthetic operons that consist of the same genes as the native operons are thus constructed and tested for functional complementation. A further exemplary description of synthetic operons is provided in US20140329326.
Microbes useful in the methods and compositions disclosed herein may be obtained from any source. In some cases, microbes may be bacteria, archaea, protozoa or fungi. The microbes of this disclosure may be nitrogen fixing microbes, for example a nitrogen fixing bacteria, nitrogen fixing archaea, nitrogen fixing fungi, nitrogen fixing yeast, or nitrogen fixing protozoa. Microbes useful in the methods and compositions disclosed herein may be spore forming microbes, for example spore forming bacteria. In some cases, bacteria useful in the methods and compositions disclosed herein may be Gram positive bacteria or Gram negative bacteria. In some cases, the bacteria may be an endospore forming bacteria of the Firmicute phylum. In some cases, the bacteria may be a diazotroph. In some cases, the bacteria may not be a diazotroph.
The methods and compositions of this disclosure may be used with an archaea, such as, for example, Methanothermobacter thermoautotrophicus.
In some cases, bacteria which may be useful include, but are not limited to, Agrobacterium radiobacter, Bacillus acidocaldarius, Bacillus acidoterrestris, Bacillus agri, Bacillus aizawai, Bacillus albolactis, Bacillus alcalophilus, Bacillus alvei, Bacillus aminoglucosidicus, Bacillus aminovorans, Bacillus amylolyticus (also known as Paenibacillus amylolyticus) Bacillus amyloliquefaciens, Bacillus aneurinolyticus, Bacillus atrophaeus, Bacillus azotoformans, Bacillus badius, Bacillus cereus (synonyms: Bacillus endorhythmos, Bacillus medusa), Bacillus chitinosporus, Bacillus circulars, Bacillus coagulans, Bacillus endoparasiticus Bacillus fastidiosus, Bacillus firmus, Bacillus kurstaki, Bacillus lacticola, Bacillus lactimorbus, Bacillus lactis, Bacillus laterosporus (also known as Brevibacillus laterosporus), Bacillus lautus, Bacillus lentimorbus, Bacillus lentus, Bacillus licheniformis, Bacillus maroccanus, Bacillus megaterium, Bacillus metiens, Bacillus mycoides, Bacillus natto, Bacillus nematocida, Bacillus nigrificans, Bacillus nigrum, Bacillus pantothenticus, Bacillus popillae, Bacillus psychrosaccharolyticus, Bacillus pumilus, Bacillus siamensis, Bacillus smithii, Bacillus sphaericus, Bacillus subtilis, Bacillus thuringiensis, Bacillus uniflagellatus, Bradyrhizobium japonicum, Brevibacillus brevis Brevibacillus laterosporus (formerly Bacillus laterosporus), Chromobacterium subtsugae, Delftia acidovorans, Klebsiella variicola, Kosokonia sacchari, Lactobacillus acidophilus, Lysobacter antibioticus, Lysobacter enzymogenes, Paenibacillus alvei, Paenibacillus polymyxa, Paenibacillus popilliae (formerly Bacillus popilliae), Pantoea agglomerans, Pasteuria penetrans (formerly Bacillus penetrans), Pasteuria usgae, Pectobacterium carotovorum (formerly Erwinia carotovora), Pseudomonas aeruginosa, Pseudomonas aureofaciens, Pseudomonas cepacia (formerly known as Burkholderia cepacia), Pseudomonas chlororaphis, Pseudomonas fluorescens, Pseudomonas proradix, Pseudomonas putida, Pseudomonas syringae, Serratia entomophila, Serratia marcescens, Streptomyces colombiensis, Streptomyces galbus, Streptomyces goshikiensis, Streptomyces griseoviridis, Streptomyces lavendulae, Streptomyces prasinus, Streptomyces saraceticus, Streptomyces venezuelae, Xanthomonas campestris, Xenorhabdus luminescens, Xenorhabdus nematophila, Rhodococcus globerulus AQ719 (NRRL Accession No. B-21663), Bacillus sp. AQ175 (ATCC Accession No. 55608), Bacillus sp. AQ 177 (ATCC Accession No. 55609), Bacillus sp. AQ178 (ATCC Accession No. 53522), and Streptomyces sp. strain NRRL Accession No. B-30145. In some cases the bacterium may be Azotobacter chroococcum, Methanosarcina barkeri, Klesiella pneumoniae, Azotobacter vinelandii, Rhodobacter spharoides, Rhodobacter capsulatus, Rhodobcter palustris, Rhodosporillum rubrum, Rhizobium leguminosarum or Rhizobium etli.
In some cases the bacterium may be a species of Clostridium, for example Clostridium pasteurianum, Clostridium beijerinckii, Clostridium perfringens, Clostridium tetani, Clostridium acetobutylicum.
In some cases, bacteria used with the methods and compositions of the present disclosure may be cyanobacteria. Examples of cyanobacterial genuses include Anabaena (for example Anagaena sp. PCC7120), Nostoc (for example Nostoc punctiforme), or Synechocystis (for example Synechocystis sp. PCC6803).
In some cases, bacteria used with the methods and compositions of the present disclosure may belong to the phylum Chlorobi, for example Chlorobium tepidum.
In some cases, microbes used with the methods and compositions of the present disclosure may comprise a gene homologous to a known NifH gene. Sequences of known NifH genes may be found in, for example, the Zehr lab NifH database, (wwwzehr.pmc.ucsc.edu/nifH_Database_Public/, Apr. 4, 2014), or the Buckley lab NifH database (www.css.cornell.edu/faculty/buckley/nifh.htm, and Gaby, John Christian, and Daniel I-I. Buckley. “A comprehensive aligned nifH gene database: a multipurpose tool for studies of nitrogen-fixing bacteria. Database 2014 (2014): bau001.). In some cases, microbes used with the methods and compositions of the present disclosure may comprise a sequence which encodes a polypeptide with at least 60%, 70%, 80%, 85%, 90%, 95%, 96%, 96%, 98%, 99% or more than 99% sequence identity to a sequence from the Zehr lab NifH database, (wwwzehr.pmc.ucsc.edu/nifH_Database_Public/, Apr. 4, 2014). In some cases, microbes used with the methods and compositions of the present disclosure may comprise a sequence which encodes a polypeptide with at least 60%, 70%, 80%, 85%, 90%, 95%, 96%, 96%, 98%, 99% or more than 99% sequence identity to a sequence from the Buckley lab NifH database, (Gaby, John Christian, and Daniel H. Buckley. “A comprehensive aligned nifH gene database: a multipurpose tool for studies of nitrogen-fixing bacteria.” Database 2014 (2014): bau001).
Microbes useful in the methods and compositions disclosed herein can be obtained by extracting microbes from surfaces or tissues of native plants; grinding seeds to isolate microbes; planting seeds in diverse soil samples and recovering microbes from tissues; or inoculating plants with exogenous microbes and determining which microbes appear in plant tissues. Non-limiting examples of plant tissues include a seed, seedling, leaf, cutting, plant, bulb, tuber, root, and rhizomes. In some cases, bacteria are isolated from a seed. The parameters for processing samples may be varied to isolate different types of associative microbes, such as rhizospheric, epiphytes, or endophytes. Bacteria may also be sourced from a repository, such as environmental strain collections, instead of initially isolating from a first plant. The microbes can be genotyped and phenotyped, via sequencing the genomes of isolated microbes; profiling the composition of communities in planta; characterizing the transcriptomic functionality of communities or isolated microbes; or screening microbial features using selective or phenotypic media (e.g., nitrogen fixation or phosphate solubilization phenotypes). Selected candidate strains or populations can be obtained via sequence data; phenotype data; plant data (e.g., genome, phenotype, and/or yield data); soil data (e.g., pH, N/P/K content, and/or bulk soil biotic communities); or any combination of these.
The bacteria and methods of producing bacteria described herein may apply to bacteria able to self-propagate efficiently on the leaf surface, root surface, or inside plant tissues without inducing a damaging plant defense reaction, or bacteria that are resistant to plant defense responses. The bacteria described herein may be isolated by culturing a plant tissue extract or leaf surface wash in a medium with no added nitrogen. However, the bacteria may be unculturable, that is, not known to be culturable or difficult to culture using standard methods known in the art. The bacteria described herein may be an endophyte or an epiphyte or a bacterium inhabiting the plant rhizosphere (rhizospheric bacteria). The bacteria obtained after repeating the steps of introducing genetic variation, exposure to a plurality of plants, and isolating bacteria from plants with an improved trait one or more times (e.g. 1, 2, 3, 4, 5, 10, 15, 25, or more times) may be endophytic, epiphytic, or rhizospheric. Endophytes are organisms that enter the interior of plants without causing disease symptoms or eliciting the formation of symbiotic structures, and are of agronomic interest because they can enhance plant growth and improve the nutrition of plants (e.g., through nitrogen fixation). The bacteria can be a seed-borne endophyte. Seed-borne endophytes include bacteria associated with or derived from the seed of a grass or plant, such as a seed-borne bacterial endophyte found in mature, dry, undamaged (e.g., no cracks, visible fungal infection, or prematurely germinated) seeds. The seed-borne bacterial endophyte can be associated with or derived from the surface of the seed; alternatively, or in addition, it can be associated with or derived from the interior seed compartment (e.g., of a surface-sterilized seed). In some cases, a seed-borne bacterial endophyte is capable of replicating within the plant tissue, for example, the interior of the seed. Also, in some cases, the seed-borne bacterial endophyte is capable of surviving desiccation.
The bacterial isolated according to methods of the disclosure, or used in methods or compositions of the disclosure, can comprise a plurality of different bacterial taxa in combination. By way of example, the bacteria may include Proteobacteria (such as Pseudomonas, Enterobacter, Stenotrophomonas, Burkholderia, Rhizobium, Herbaspirillum, Pantoea, Serratia, Rahnella, Azospirillum, Azorhizobium, Azotobacter, Duganella, Delftia, Bradyrhizobiun, Sinorhizobium and Halomonas), Firmicutes (such as Bacillus, Paenibacillus, Lactobacillus, Mycoplasma, and Acetabacterium), and Actinobacteria (such as Streptomyces, Rhodacoccus, Microbacterium, and Curtobacterium). The bacteria used in methods and compositions of this disclosure may include nitrogen fixing bacterial consortia of two or more species. In some cases, one or more bacterial species of the bacterial consortia may be capable of fixing nitrogen. In some cases, one or more species of the bacterial consortia may facilitate or enhance the ability of other bacteria to fix nitrogen. The bacteria which fix nitrogen and the bacteria which enhance the ability of other bacteria to fix nitrogen may be the same or different. In some examples, a bacterial strain may be able to fix nitrogen when in combination with a different bacterial strain, or in a certain bacterial consortia, but may be unable to fix nitrogen in a monoculture. Examples of bacterial genuses which may be found in a nitrogen fixing bacterial consortia include, but are not limited to, Herbaspirillum, Azospirillum, Enterobacter, and Bacillus.
Bacteria that can be produced by the methods disclosed herein include Azotobacter sp., Bradyrhizobium sp., Klebsiella sp., Kosakonia sp., and Sinorhizobium sp. In some cases, the bacteria may be selected from the group consisting of: Azotobacter vinelandii, Bradyrhizobium japonicum, Klebsiella pneumoniae, Klebsiellavariicola, Kosakonia sacchari, and Sinorhizobium meliloti. In some cases, the bacteria may be of the genus Enterobacter or Rahnella. In some cases, the bacteria may be of the genus Frankia, or Clostridium. Examples of bacteria of the genus Clostridium include, but are not limited to, Clostridium acetobutilicum, Clostridium pasteurianum, Clostridium beijerinckii, Clostridium perfringens, and Clostridium tetani. In some cases, the bacteria may be of the genus Paenibacillus, for example Paenibacillus azotofixans, Paenibacillus borealis, Paenibacillus durus, Paenibacillus macerans, Paenibacillus polymyxa, Paenibacillus alvei, Paenibacillus amylolyticus, Paenibacillus campinasensis, Paenibacillus chibensis, Paenibacillus glucanolyticus, Paenibacillus illinoisensis, Paenibacillus larvae subsp. Larvae, Paenibacillus larvae subsp. Pulvifaciens, Paenibacillus lautus, Paenibacillus macerans, Paenibacillus macquariensis, Paenibacillus macquariensis, Paenibacillus pabuli, Paenibacillus peoriae, or Paenibacillus polymyxa.
In some examples, bacteria isolated according to methods of the disclosure can be a member of one or more of the following taxa: Achromobacter, Acidithiobacillus, Acidovorax, Acidovoraz, Acinetobacter, Actinoplanes, Adlercreutzia, Aerococcus, Aeromonas, Afipia, Agromyces, Ancylobacter, Arthrobacter, Atopostipes, Azospirillum, Bacillus, Bdellovibrio, Beijerinckia, Bosea, Bradyrhizobium, Brevibacillus, Brevundimonas, Burkholderia, Candidatus Haloredivivus, Caulobacter, Cellulomonas, Cellvibrio, Chryseobacterium, Citrobacter, Clostridium, Coraliomargarita, Corynebacterium, Cupriavidus, Curtobacterium, Curvibacter, Deinococcus, Delftia, Desemzia, Devosia, Dokdonella, Dyella, Enhydrobacter, Enterobacter, Enterococcus, Erwinia, Escherichia, Escherichia/Shigella, Exiguobacterium, Ferroglobus, Filimonas, Finegoldia, Flavisolibacter, Flavobacterium, Frigoribacterium, Gluconacetobacter, Hafnia, Halobaculum, Halomonas, Halosimplex, Herbaspirillum, Hymenobacter, Klebsiella, Kocuria, Kosakonia, Lactobacillus, Leclercia, Lentzea, Luteibacter, Luteimonas, Massilia, Mesorhizobium, Methylobacterium, Microbacterium, Micrococcus, Microvirga, Mycobacterium, Neisseria, Nocardia, Oceanibaculum, Ochrobactrum, Okibacterium, Oligotropha, Oryzihumus, Oxalophagus, Paenibacillus, Panteoa, Pantoea, Pelomonas, Perlucidibaca, Plantibacter, Polynucleobacter, Propionibacterium, Propioniciclava, Pseudoclavibacter, Pseudomonas, Pseudonocardia, Pseudoxanthomonas, Psychrobacter, Rahnella, Ralstonia, Rheinheimera, Rhizobium, Rhodococcus, Rhodopseudomonas, Roseateles, Ruminococcus, Sebaldella, Sediminibacterium, Serratia, Shigella, Shinella, Sinorhizobium, Sinosporangium, Sphingobacterium, Sphingomonas, Sphingopyxis, Sphingosinicella, Staphylococcus, 25 Stenotrophomonas, Strenotrophomonas, Streptococcus, Streptomyces, Stygiolobus, Sulfurisphaera, Tatumella, Tepidimonas, Thermomonas, Thiobacillus, Variovorax, WPS-2 genera incertae sedis, Xanthomonas, and Zimmermannella.
In some cases, a bacterial species selected from at least one of the following genera are utilized: Enterobacter, Klebsiella, Kosakonia, and Rahnella. In some cases, a combination of bacterial species from the following genera are utilized: Enterobacter, Klebsiella, Kosakonia, and Rahnella. In some cases, the species utilized can be one or more of: Enterobacter sacchari, Klebsiellavariicola, Kosakonia sacchari, and Rahnella aquatilis.
In some cases, a Gram positive microbe may have a Molybdenum-Iron nitrogenase system comprising: nifH, nifD, nifK, nifB, nifE, nifty, nifX, hesA, nifV, nifW, nifU, nifS, and MN. In some cases, a Gram positive microbe may have a vanadium nitrogenase system comprising: vnfDG, vnfK, vnfE, vnfN, vupC, vupB, vupA, vnfV, vnfR1, vnfH, vnfR2, vnfA (transcriptional regulator). In some cases, a Gram positive microbe may have an iron-only nitrogenase system comprising: anfK, anfG, anfD, anfH, anfA (transcriptional regulator). In some cases, a Gram positive microbe may have a nitrogenase system comprising glnB, and glnK (nitrogen signaling proteins). Some examples of enzymes involved in nitrogen metabolism in Gram positive microbes include glnA (glutamine synthetase), gdh (glutamate dehydrogenase), bdh (3-hydroxybutyrate dehydrogenase), glutaminase, gltAB/gltB/gltS (glutamate synthase), asnA/asnB (aspartate-ammonia ligase/asparagine synthetase), and ansA/ansZ (asparaginase). Some examples of proteins involved in nitrogen transport in Gram positive microbes include amtB (ammonium transporter), glnK (regulator of ammonium transport), glnPHQ/glnQHMP (ATP-dependent glutamine/glutamate transporters), glnT/alsT/yrbD/yflA (glutamine-like proton symport transporters), and gltP/gltT/yhcl/nqt (glutamate-like proton symport transporters).
Examples of Gram positive microbes which may be of particular interest include Paenibacillus polymixa, Paenibacillus riograndensis, Paenibacillus sp., Frankia sp., Heliobacterium sp., Heliobacterium chlorum, Heliobacillus sp., Heliophilum sp., Heliorestis sp., Clostridium acetobutylicum, Clostridium sp., Mycobacterium flaum, Mycobacterium sp., Arthrobacter sp., Agromyces sp., Corynebacterium autitrophicum, Corynebacterium sp., Micromonspora sp., Propionibacteria sp., Streptomyces sp., and Microbacterium sp.
Some examples of genetic alterations which may be made in Gram positive microbes include: deleting glnR to remove negative regulation of BNF in the presence of environmental nitrogen, inserting different promoters directly upstream of the nif cluster to eliminate regulation by GlnR in response to environmental nitrogen, mutating glnA to reduce the rate of ammonium assimilation by the GS-GOGAT pathway, deleting amtB to reduce uptake of ammonium from the media, mutating glnA so it is constitutively in the feedback-inhibited (FBI-GS) state, to reduce ammonium assimilation by the GS-GOGAT pathway.
In some cases, glnR is the main regulator of N metabolism and fixation in Paenibacillus species. In some cases, the genome of a Paenibacillus species may not contain a gene to produce glnR. In some cases, the genome of a Paenibacillus species may not contain a gene to produce glnE or glnD. In some cases, the genome of a Paenibacillus species may contain a gene to produce glnB or glnK. For example, Paenibacillus sp. WLY78 doesn't contain a gene for glnB, or its homologs found in the archaeon Methanococcus maripaludis, nifI1 and nifI2. In some cases, the genomes of Paenibacillus species may be variable. For example, Paenibacillus polymixa E681 lacks glnK and gdh, has several nitrogen compound transporters, but only amtB appears to be controlled by GlnR. In another example, Paenibacillus sp. JDR2 has glnK, gdh and most other central nitrogen metabolism genes, has many fewer nitrogen compound transporters, but does have glnPHQ controlled by GlnR. Paenibacillus riograndensis SBR5 contains a standard glnRA operon, an fdx gene, a main nif operon, a secondary nif operon, and an anf operon (encoding iron-only nitrogenase). Putative glnR/tnrA sites were found upstream of each of these operons. GlnR may regulate all of the above operons, except the anf operon. GlnR may bind to each of these regulatory sequences as a dimer.
Paenibacillus N-fixing strains may fall into two subgroups: Subgroup I, which contains only a minimal nif gene cluster and subgroup II, which contains a minimal cluster, plus an uncharacterized gene between nifX and hesA, and often other clusters duplicating some of the nif genes, such as nifH, nifHDK, nifBEN, or clusters encoding vanadaium nitrogenase (vnf) or iron-only nitrogenase (anf) genes.
In some cases, the genome of a Paenibacillus species may not contain a gene to produce glnB or glnK. In some cases, the genome of a Paenibacillus species may contain a minimal nif cluster with 9 genes transcribed from a sigma-70 promoter. In some cases, a Paenibacillus nif cluster may be negatively regulated by nitrogen or oxygen. In some cases, the genome of a Paenibacillus species may not contain a gene to produce sigma-54. For example, Paenibacillus sp. WLY78 does not contain a gene for sigma-54. In some cases, a nif cluster may be regulated by glnR, and/or TnrA. In some cases, activity of a nif cluster may be altered by altering activity of glnR, and/or TnrA.
In Bacilli, glutamine synthetase (GS) is feedback-inhibited by high concentrations of intracellular glutamine, causing a shift in confirmation (referred to as FBI-GS). Nif clusters contain distinct binding sites for the regulators GlnR and TnrA in several Bacilli species. GlnR binds and represses gene expression in the presence of excess intracellular glutamine and AMP. A role of GlnR may be to prevent the influx and intracellular production of glutamine and ammonium under conditions of high nitrogen availability. TnrA may bind and/or activate (or repress) gene expression in the presence of limiting intracellular glutamine, and/or in the presence of FBI-GS. In some cases, the activity of a Bacilli nif cluster may be altered by altering the activity of GlnR.
Feedback-inhibited glutamine synthetase (FBI-GS) may bind GlnR and stabilize binding of GlnR to recognition sequences. Several bacterial species have a GlnR/TnrA binding site upstream of the nif cluster. Altering the binding of FBI-GS and GlnR may alter the activity of the nif pathway.
The bacteria (or any microbe according to the disclosure) may be obtained from any general terrestrial environment, including its soils, plants, fungi, animals (including invertebrates) and other biota, including the sediments, water and biota of lakes and rivers; from the marine environment, its biota and sediments (for example, sea water, marine muds, marine plants, marine invertebrates (for example, sponges), marine vertebrates (for example, fish)); the terrestrial and marine geosphere (regolith and rock, for example, crushed subterranean rocks, sand and clays); the cryosphere and its meltwater; the atmosphere (for example, filtered aerial dusts, cloud and rain droplets); urban, industrial and other man-made environments (for example, accumulated organic and mineral matter on concrete, roadside gutters, roof surfaces, and road surfaces).
The plants from which the bacteria (or any microbe according to the disclosure) are obtained may be a plant having one or more desirable traits, for example a plant which naturally grows in a particular environment or under certain conditions of interest. By way of example, a certain plant may naturally grow in sandy soil or sand of high salinity, or under extreme temperatures, or with little water, or it may be resistant to certain pests or disease present in the environment, and it may be desirable for a commercial crop to be grown in such conditions, particularly if they are, for example, the only conditions available in a particular geographic location. By way of further example, the bacteria may be collected from commercial crops grown in such environments, or more specifically from individual crop plants best displaying a trait of interest amongst a crop grown in any specific environment: for example the fastest-growing plants amongst a crop grown in saline-limiting soils, or the least damaged plants in crops exposed to severe insect damage or disease epidemic, or plants having desired quantities of certain metabolites and other compounds, including fiber content, oil content, and the like, or plants displaying desirable colors, taste or smell. The bacteria may be collected from a plant of interest or any material occurring in the environment of interest, including fungi and other animal and plant biota, soil, water, sediments, and other elements of the environment as referred to previously.
The bacteria (or any microbe according to the disclosure) may be isolated from plant tissue. This isolation can occur from any appropriate tissue in the plant, including for example root, stem and leaves, and plant reproductive tissues. By way of example, conventional methods for isolation from plants typically include the sterile excision of the plant material of interest (e.g. root or stem lengths, leaves), surface sterilization with an appropriate solution (e.g. 2% sodium hypochlorite), after which the plant material is placed on nutrient medium for microbial growth. Alternatively, the surface-sterilized plant material can be crushed in a sterile liquid (usually water) and the liquid suspension, including small pieces of the crushed plant material spread over the surface of a suitable solid agar medium, or media, which may or may not be selective (e.g. contain only phytic acid as a source of phosphorus). This approach is especially useful for bacteria which form isolated colonies and can be picked off individually to separate plates of nutrient medium, and further purified to a single species by well-known methods. Alternatively, the plant root or foliage samples may not be surface sterilized but only washed gently thus including surface-dwelling epiphytic microorganisms in the isolation process, or the epiphytic microbes can be isolated separately, by imprinting and lifting off pieces of plant roots, stem or leaves onto the surface of an agar medium and then isolating individual colonies as above. This approach is especially useful for bacteria, for example. Alternatively, the roots may be processed without washing off small quantities of soil attached to the roots, thus including microbes that colonize the plant rhizosphere. Otherwise, soil adhering to the roots can be removed, diluted and spread out onto agar of suitable selective and non-selective media to isolate individual colonies of rhizospheric bacteria.
The microbial deposits of the present disclosure were made under the provisions of the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purpose of Patent Procedure (Budapest Treaty).
Applicants state that pursuant to 37 C.F.R. § 1.808(a)(2) “all restrictions imposed by the depositor on the availability to the public of the deposited material will be irrevocably removed upon the granting of the patent.” This statement is subject to paragraph (b) of this section (i.e. 37 C.F.R. § 1.808(b)).
The Enterobacter sacchari has now been reclassified as Kosakonia sacchari, the name for the organism may be used interchangeably throughout the manuscript.
Many microbes of the present disclosure are derived from two wild-type strains, as depicted in
Some microorganisms described in this application were deposited on Jan. 6, 2017 or Aug. 11, 2017 with the Bigelow National Center for Marine Algae and Microbiota (NCMA), located at 60 Bigelow Drive, East Boothbay, Me. 04544, USA. As aforementioned, all deposits were made under the terms of the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Procedure. The Bigelow National Center for Marine Algae and Microbiota accession numbers and dates of deposit for the aforementioned Budapest Treaty deposits are provided in Table 1.
Biologically pure cultures of Kosakonia sacchari (WT), Rahnella aquatilis (WT), and a variant/remodeled Kosakonia sacchari strain were deposited on Jan. 6, 2017 with the Bigelow National Center for Marine Algae and Microbiota (NCMA), located at 60 Bigelow Drive, East Boothbay, Me. 04544, USA, and assigned NCMA Patent Deposit Designation numbers 201701001, 201701003, and 201701002, respectively. The applicable deposit information is found below in Table 1.
Biologically pure cultures of variant/remodeled Kosakonia sacchari strains were deposited on Aug. 11, 2017 with the Bigelow National Center for Marine Algae and Microbiota (NCMA), located at 60 Bigelow Drive, East Boothbay, Me. 04544, USA, and assigned NCMA Patent Deposit Designation numbers 201708004, 201708003, and 201708002, respectively. The applicable deposit information is found below in Table 1.
A biologically pure culture of Klebsiella variicola (WT) was deposited on Aug. 11, 2017 with the Bigelow National Center for Marine Algae and Microbiota (NCMA), located at 60 Bigelow Drive, East Boothbay, Me. 04544, USA, and assigned NCMA Patent Deposit Designation number 201708001. Biologically pure cultures of two Klebsiella variicola variants/remodeled strains were deposited on Dec. 20, 2017 with the Bigelow National Center for Marine Algae and Microbiota (NCMA), located at 60 Bigelow Drive, East Boothbay, Me. 04544, USA, and assigned NCMA Patent Deposit Designation numbers 201712001 and 201712002, respectively. The applicable deposit information is found below in Table 1.
Biologically pure cultures of two Kosakonia sacchari variants/remodeled strains were deposited on Dec. 23, 2019 with the American Type Culture Collection (ATCC), located at 10801 University Boulevard, Manassas, Va. 20110-2209, USA and assigned ATCC Patent Deposit Numbers PTA-126575 and PTA-126576. Biologically pure cultures of four Klebsiella variicola variants/remodeled strains were deposited on Dec. 23, 2019 with the American Type Culture Collection (ATCC), located at 10801 University Boulevard, Manassas, Va. 20110-2209, USA and assigned ATCC Patent Deposit Numbers PTA-126577, PTA-126578, PTA-126579 and PTA-126580. A biologically pure culture of a Paenibacillus polymyxa (WT) strain was deposited on Dec. 23, 2019 with the American Type Culture Collection (ATCC), located at 10801 University Boulevard, Manassas, Va. 20110-2209, USA and assigned ATCC Patent Deposit Number PTA-126581. A biologically pure culture of a Paraburkholderia tropica (WT) strain was deposited on Dec. 23, 2019 with the American Type Culture Collection (ATCC), located at 10801 University Boulevard, Manassas, Va. 20110-2209, USA and assigned ATCC Patent Deposit Number PTA-126582. A biologically pure culture of a Herbaspirillum aquaticum (WT) strain was deposited on Dec. 23, 2019 with the American Type Culture Collection (ATCC), located at 10801 University Boulevard, Manassas, Va. 20110-2209, USA and assigned ATCC Patent Deposit Number PTA-126583. Biologically pure cultures of four Metakosakonia intestini variants/remodeled strains were deposited on Dec. 23, 2019 with the American Type Culture Collection (ATCC), located at 10801 University Boulevard, Manassas, Va. 20110-2209, USA and assigned ATCC Patent Deposit Numbers PTA-126584, PTA-126586, PTA-126587 and PTA-126588. A biologically pure culture of a Metakosakonia intestini (WT) strain was deposited on Dec. 23, 2019 with the American Type Culture Collection (ATCC), located at 10801 University Boulevard, Manassas, Va. 20110-2209, USA and assigned ATCC Patent Deposit Number PTA-126585. The applicable deposit information is found below in Table 1.
A biologically pure culture of Klebsiella variicola designated 137-2253 was deposited on Mar. 25, 2020, with the American Type Culture Collection (ATCC), located at 10801 University Boulevard, Manassas, Va. 20110-2209, USA and assigned ATCC Patent Deposit Designation number PTA-126740. This deposit was made under the provisions of the Budapest Treaty.
A biologically pure culture of Kosokonia sacchari designated 6-2122 was deposited on Mar. 25, 2020, with the American Type Culture Collection (ATCC), located at 10801 University Boulevard, Manassas, Va. 20110-2209, USA and assigned ATCC Patent Deposit Designation number PTA-126743. This deposit was made under the provisions of the Budapest Treaty.
A biologically pure culture of Klebsiella variicola designated 137-3896 was deposited on Mar. 25, 2020, with the American Type Culture Collection (ATCC), located at 10801 University Boulevard, Manassas, Va. 20110-2209, USA and assigned ATCC Patent Deposit Designation number PTA-126741. This deposit was made under the provisions of the Budapest Treaty.
A biologically pure culture of Klebsiella variicola designated 137-3890 was deposited on Apr. 2, 2020, with the American Type Culture Collection (ATCC), located at 10801 University Boulevard, Manassas, Va. 20110-2209, USA and assigned ATCC Patent Deposit Designation number PTA-126749. This deposit was made under the provisions of the Budapest Treaty.
Kosakonia
sacchari
Rahnella
aquatilis
Kosakonia
sacchari
Kosakonia
sacchari
Kosakonia
sacchari
Kosakonia
sacchari
Klebsiella
variicola
Klebsiella
variicola
Klebsiella
variicola
Kosakonia
sacchari
Kosakonia
sacchari
Klebsiella
variicola
Klebsiella
variicola
Klebsiella
variicola
Klebsiella
variicola
Paenibacillus
polymyxa
Paraburkholderia
tropica
Herbaspirillum
aquaticum (WT)
Metakosakonia
intestini
Metakosakonia
intestini
Metakosakonia
intestini
Metakosakonia
intestini
Metakosakonia
intestini
The present disclosure, in certain embodiments, provides isolated and biologically pure microorganisms that have applications, inter alia, in agriculture. The disclosed microorganisms can be utilized in their isolated and biologically pure states, as well as being formulated into compositions (see below section for exemplary composition descriptions). Furthermore, the disclosure provides microbial compositions containing at least two members of the disclosed isolated and biologically pure microorganisms, as well as methods of utilizing said microbial compositions. Furthermore, the disclosure provides for methods of modulating nitrogen fixation in plants via the utilization of the disclosed isolated and biologically pure microbes.
In some aspects, the isolated and biologically pure microorganisms of the disclosure are those from Table 1. In other aspects, the isolated and biologically pure microorganisms of the disclosure are derived from a microorganism of Table 1. For example, a strain, child, mutant, or derivative, of a microorganism from Table 1 are provided herein. The disclosure contemplates all possible combinations of microbes listed in Table 1, said combinations sometimes forming a microbial consortia. The microbes from Table 1, either individually or in any combination, can be combined with any plant, active molecule (synthetic, organic, etc.), adjuvant, carrier, supplement, or biological, mentioned in the disclosure.
In some aspects, the disclosure provides microbial compositions comprising species as grouped in Tables 2-8. In some aspects, these compositions comprising various microbial species are termed a microbial consortia or consortium. Tables 2-8 are provided to illustrate some, but not all, of the combinations of microbes.
With respect to Tables 2-8, the letters A through K represent a non-limiting selection of microorganisms of the present disclosure, defined as:
A=Microbe with accession number 201701001 identified in Table 1;
B=Microbe with accession number 201701003 identified in Table 1;
C=Microbe with accession number 201701002 identified in Table 1;
D=Microbe with accession number 201708004 identified in Table 1;
E=Microbe with accession number 201708003 identified in Table 1;
F=Microbe with accession number 201708002 identified in Table 1;
G=Microbe with accession number 201708001 identified in Table 1;
H=Microbe with accession number 201712001 identified in Table 1;
I=Microbe with accession number 201712002 identified in Table 1;
J=Microbe with accession number PTA-126740; and
K=Microbe with accession number PTA-126743.
In some embodiments, microbial compositions may be selected from any member group from Tables 2-8.
Compositions comprising bacteria or bacterial populations produced according to methods described herein and/or having characteristics as described herein can be in the form of a liquid, a foam, or a dry product. Compositions comprising bacteria or bacterial populations produced according to methods described herein and/or having characteristics as described herein may also be used to improve plant traits. In some examples, a composition comprising bacterial populations may be in the form of a dry powder, a slurry of powder and water, or a flowable seed treatment. The compositions comprising bacterial populations may be coated on a surface of a seed, and may be in liquid form.
The composition can be fabricated in bioreactors such as continuous stirred tank reactors, batch reactors, and on the farm. In some examples, compositions can be stored in a container, such as a jug or in mini bulk. In some examples, compositions may be stored within an object selected from the group consisting of a bottle, jar, ampule, package, vessel, bag, box, bin, envelope, carton, container, silo, shipping container, truck bed, and case.
Compositions may also be used to improve plant traits. In some examples, one or more compositions may be coated onto a seed. In some examples, one or more compositions may be coated onto a seedling. In some examples, one or more compositions may be coated onto a surface of a seed. In some examples, one or more compositions may be coated as a layer above a surface of a seed. In some examples, a composition that is coated onto a seed may be in liquid form, in dry product form, in foam form, in a form of a slurry of powder and water, or in a flowable seed treatment. In some examples, one or more compositions may be applied to a seed and/or seedling by spraying, immersing, coating, encapsulating, and/or dusting the seed and/or seedling with the one or more compositions. In some examples, multiple bacteria or bacterial populations can be coated onto a seed and/or a seedling of the plant. In some examples, at least two, at least three, at least four, at least five, at least six, at least seven, at least eight, at least nine, at least ten, or more than ten bacteria of a bacterial combination can be selected from one of the following genera: Acidovorax, Agrobacterium, Bacillus, Burkholderia, Chryseobacterium, Curtobacterium, Enterobacter, Escherichia, Klebsiella, Kosakonia, Methylobacterium, Paenibacillus, Pantoea, Pseudomonas, Ralstonia, Saccharibacillus, Sphingomonas, and Stenotrophomonas.
In some examples, at least two, at least three, at least four, at least five, at least six, at least seven, at least eight, at least nine, at least ten, or more than ten bacteria and bacterial populations of an endophytic combination are selected from one of the following families: Bacillaceae, Burkholderiaceae, Comamonadaceae, Enterobacteriaceae, Flavobacteriaceae, Methylobacteriaceae, Microbacteriaceae, Paenibacillileae, Pseudomonnaceae, Rhizobiaceae, Sphingomonadaceae, Xanthomonadaceae, Cladosporiaceae, Gnomoniaceae, Incertae sedis, Lasiosphaeriaceae, Netriaceae, and Pleosporaceae.
In some examples, at least two, at least three, at least four, at least five, at least six, at least seven, at least eight, at least night, at least ten, or more than ten bacteria and bacterial populations of an endophytic combination are selected from one of the following families: Bacillaceae, Burkholderiaceae, Comamonadaceae, Enterobacteriaceae, Flavobacteriaceae, Methylobacteriaceae, Microbacteriaceae, Paenibacillileae, Pseudomonnaceae, Rhizobiaceae, Sphingomonadaceae, Xanthomonadaceae, Cladosporiaceae, Gnomoniaceae, Incertae sedis, Lasiosphaeriaceae, Netriaceae, Pleosporaceae.
Examples of compositions may include seed coatings for commercially important agricultural crops, for example, sorghum, canola, tomato, strawberry, barley, rice, maize, and wheat. Examples of compositions can also include seed coatings for corn, soybean, canola, sorghum, potato, rice, vegetables, cereals, and oilseeds. Seeds as provided herein can be genetically modified organisms (GMO), non-GMO, organic, or conventional. In some examples, compositions may be sprayed on the plant aerial parts, or applied to the roots by inserting into furrows in which the plant seeds are planted, watering to the soil, or dipping the roots in a suspension of the composition. In some examples, compositions may be dehydrated in a suitable manner that maintains cell viability and the ability to artificially inoculate and colonize host plants. The bacterial species may be present in compositions at a concentration of between 108 to 1010 CFU/ml. In some examples, compositions may be supplemented with trace metal ions, such as molybdenum ions, iron ions, manganese ions, or combinations of these ions. The concentration of ions in examples of compositions as described herein may between about 0.1 mM and about 50 mM. Some examples of compositions may also be formulated with a carrier, such as beta-glucan, carboxylmethyl cellulose (CMC), bacterial extracellular polymeric substance (EPS), sugar, animal milk, or other suitable carriers. In some examples, peat or planting materials can be used as a carrier, or biopolymers in which a composition is entrapped in the biopolymer can be used as a carrier. The compositions comprising the bacterial populations described herein can improve plant traits, such as promoting plant growth, maintaining high chlorophyll content in leaves, increasing fruit or seed numbers, and increasing fruit or seed unit weight.
The compositions comprising the bacterial populations described herein may be coated onto the surface of a seed. As such, compositions comprising a seed coated with one or more bacteria described herein are also contemplated. The seed coating can be formed by mixing the bacterial population with a porous, chemically inert granular carrier. Alternatively, the compositions may be inserted directly into the furrows into which the seed is planted or sprayed onto the plant leaves or applied by dipping the roots into a suspension of the composition. An effective amount of the composition can be used to populate the sub-soil region adjacent to the roots of the plant with viable bacterial growth, or populate the leaves of the plant with viable bacterial growth. In general, an effective amount is an amount sufficient to result in plants with improved traits (e.g. a desired level of nitrogen fixation).
Bacterial compositions described herein can be formulated using an agriculturally acceptable carrier. The formulation useful for these embodiments may include at least one member selected from the group consisting of a tackifier, a microbial stabilizer, a fungicide, an antibacterial agent, a preservative, a stabilizer, a surfactant, an anti-complex agent, an herbicide, a nematicide, an insecticide, a plant growth regulator, a fertilizer, a rodenticide, a dessicant, a bactericide, a nutrient, and any combination thereof. In some examples, compositions may be shelf-stable. For example, any of the compositions described herein can include an agriculturally acceptable carrier (e.g., one or more of a fertilizer such as a non-naturally occurring fertilizer, an adhesion agent such as a non-naturally occurring adhesion agent, and a pesticide such as a non-naturally occurring pesticide). A non-naturally occurring adhesion agent can be, for example, a polymer, copolymer, or synthetic wax. For example, any of the coated seeds, seedlings, or plants described herein can contain such an agriculturally acceptable carrier in the seed coating. In any of the compositions or methods described herein, an agriculturally acceptable carrier can be or can include a non-naturally occurring compound (e.g., a non-naturally occurring fertilizer, a non-naturally occurring adhesion agent such as a polymer, copolymer, or synthetic wax, or a non-naturally occurring pesticide). Non-limiting examples of agriculturally acceptable carriers are described below. Additional examples of agriculturally acceptable carriers are known in the art.
In some cases, bacteria are mixed with an agriculturally acceptable carrier. The carrier can be a solid carrier or liquid carrier, and in various forms including microspheres, powders, emulsions and the like. The carrier may be any one or more of a number of carriers that confer a variety of properties, such as increased stability, wettability, or dispersability. Wetting agents such as natural or synthetic surfactants, which can be nonionic or ionic surfactants, or a combination thereof can be included in the composition. Water-in-oil emulsions can also be used to formulate a composition that includes the isolated bacteria (see, for example, U.S. Pat. No. 7,485,451). Suitable formulations that may be prepared include wettable powders, granules, gels, agar strips or pellets, thickeners, and the like, microencapsulated particles, and the like, liquids such as aqueous flowables, aqueous suspensions, water-in-oil emulsions, etc. The formulation may include grain or legume products, for example, ground grain or beans, broth or flour derived from grain or beans, starch, sugar, or oil.
In some embodiments, the agricultural carrier may be soil or a plant growth medium. Other agricultural carriers that may be used include water, fertilizers, plant-based oils, humectants, or combinations thereof. Alternatively, the agricultural carrier may be a solid, such as diatomaceous earth, loam, silica, alginate, clay, bentonite, vermiculite, seed cases, other plant and animal products, or combinations, including granules, pellets, or suspensions. Mixtures of any of the aforementioned ingredients are also contemplated as carriers, such as but not limited to, pesta (flour and kaolin clay), agar or flour-based pellets in loam, sand, or clay, etc. Formulations may include food sources for the bacteria, such as barley, rice, or other biological materials such as seed, plant parts, sugar cane bagasse, hulls or stalks from grain processing, ground plant material or wood from building site refuse, sawdust or small fibers from recycling of paper, fabric, or wood.
For example, a fertilizer can be used to help promote the growth or provide nutrients to a seed, seedling, or plant. Non-limiting examples of fertilizers include nitrogen, phosphorous, potassium, calcium, sulfur, magnesium, boron, chloride, manganese, iron, zinc, copper, molybdenum, and selenium (or a salt thereof). Additional examples of fertilizers include one or more amino acids, salts, carbohydrates, vitamins, glucose, NaCl, yeast extract, NH4H2PO4, (NH4)2SO4, glycerol, valine, L-leucine, lactic acid, propionic acid, succinic acid, malic acid, citric acid, KH tartrate, xylose, lyxose, and lecithin. In one embodiment, the formulation can include a tackifier or adherent (referred to as an adhesive agent) to help bind other active agents to a substance (e.g., a surface of a seed). Such agents are useful for combining bacteria with carriers that can contain other compounds (e.g., control agents that are not biologic), to yield a coating composition. Such compositions help create coatings around the plant or seed to maintain contact between the microbe and other agents with the plant or plant part. In one embodiment, adhesives are selected from the group consisting of: alginate, gums, starches, lecithins, formononetin, polyvinyl alcohol, alkali formononetinate, hesperetin, polyvinyl acetate, cephalins, Gum Arabic, Xanthan Gum, Mineral Oil, Polyethylene Glycol (PEG), Polyvinyl pyrrolidone (PVP), Arabino-galactan, Methyl Cellulose, PEG 400, Chitosan, Polyacrylamide, Polyacrylate, Polyacrylonitrile, Glycerol, Triethylene glycol, Vinyl Acetate, Gellan Gum, Polystyrene, Polyvinyl, Carboxymethyl cellulose, Gum Ghatti, and polyoxyethylene-polyoxybutylene block copolymers.
In some embodiments, the adhesives can be, e.g. a wax such as carnauba wax, beeswax, Chinese wax, shellac wax, spermaceti wax, candelilla wax, castor wax, ouricury wax, and rice bran wax, a polysaccharide (e.g., starch, dextrins, maltodextrins, alginate, and chitosans), a fat, oil, a protein (e.g., gelatin and zeins), gum arables, and shellacs. Adhesive agents can be non-naturally occurring compounds, e.g., polymers, copolymers, and waxes. For example, non-limiting examples of polymers that can be used as an adhesive agent include: polyvinyl acetates, polyvinyl acetate copolymers, ethylene vinyl acetate (EVA) copolymers, polyvinyl alcohols, polyvinyl alcohol copolymers, celluloses (e.g., ethylcelluloses, methylcelluloses, hydroxymethylcelluloses, hydroxypropylcelluloses, and carboxymethylcelluloses), polyvinylpyrolidones, vinyl chloride, vinylidene chloride copolymers, calcium lignosulfonates, acrylic copolymers, polyvinylacrylates, polyethylene oxide, acylamide polymers and copolymers, polyhydroxyethyl acrylate, methylacrylamide monomers, and polychloroprene.
In some examples, one or more of the adhesion agents, anti-fungal agents, growth regulation agents, and pesticides (e.g., insecticide) are non-naturally occurring compounds (e.g., in any combination). Additional examples of agriculturally acceptable carriers include dispersants (e.g., polyvinylpyrrolidone/vinyl acetate PVPIVA S-630), surfactants, binders, and filler agents.
The formulation can also contain a surfactant. Non-limiting examples of surfactants include nitrogen-surfactant blends such as Prefer 28 (Cenex), Surf-N(US), Inhance (Brandt), P-28 (Wilfarm) and Patrol (Helena); esterified seed oils include Sun-It II (AmCy), MSO (UAP), Scoil (Agsco), Hasten (Wilfarm) and Mes-100 (Drexel); and organo-silicone surfactants include Silwet L77 (UAP), Silikin (Terra), Dyne-Amic (Helena), Kinetic (Helena), Sylgard 309 (Wilbur-Ellis) and Century (Precision). In one embodiment, the surfactant is present at a concentration of between 0.01% v/v to 10% v/v. In another embodiment, the surfactant is present at a concentration of between 0.1% v/v to 1% v/v.
In certain cases, the formulation includes a microbial stabilizer. Such an agent can include a desiccant, which can include any compound or mixture of compounds that can be classified as a desiccant regardless of whether the compound or compounds are used in such concentrations that they in fact have a desiccating effect on a liquid inoculant. Such desiccants are ideally compatible with the bacterial population used, and should promote the ability of the microbial population to survive application on the seeds and to survive desiccation. Examples of suitable desiccants include one or more of trehalose, sucrose, glycerol, and Methylene glycol. Other suitable desiccants include, but are not limited to, non reducing sugars and sugar alcohols (e.g., mannitol or sorbitol). The amount of desiccant introduced into the formulation can range from about 5% to about 50% by weight/volume, for example, between about 10% to about 40%, between about 15% to about 35%, or between about 20% to about 30%. In some cases, it is advantageous for the formulation to contain agents such as a fungicide, an antibacterial agent, an herbicide, a nematicide, an insecticide, a plant growth regulator, a rodenticide, bactericide, or a nutrient. In some examples, agents may include protectants that provide protection against seed surface-borne pathogens. In some examples, protectants may provide some level of control of soil-borne pathogens. In some examples, protectants may be effective predominantly on a seed surface.
In some examples, a fungicide may include a compound or agent, whether chemical or biological, that can inhibit the growth of a fungus or kill a fungus. In some examples, a fungicide may include compounds that may be fungistatic or fungicidal. In some examples, fungicide can be a protectant, or agents that are effective predominantly on the seed surface, providing protection against seed surface-borne pathogens and providing some level of control of soil-borne pathogens. Non-limiting examples of protectant fungicides include captan, maneb, thiram, or fludioxonil.
In some examples, fungicide can be a systemic fungicide, which can be absorbed into the emerging seedling and inhibit or kill the fungus inside host plant tissues. Systemic fungicides used for seed treatment include, but are not limited to the following: azoxystrobin, carboxin, mefenoxam, metalaxyl, thiabendazole, trifloxystrobin, and various triazole fungicides, including difenoconazole, ipconazole, tebuconazole, and triticonazole. Mefenoxam and metalaxyl are primarily used to target the water mold fungi Pythium and Phytophthora. Some fungicides are preferred over others, depending on the plant species, either because of subtle differences in sensitivity of the pathogenic fungal species, or because of the differences in the fungicide distribution or sensitivity of the plants. In some examples, fungicide can be a biological control agent, such as a bacterium or fungus. Such organisms may be parasitic to the pathogenic fungi, or secrete toxins or other substances which can kill or otherwise prevent the growth of fungi. Any type of fungicide, particularly ones that are commonly used on plants, can be used as a control agent in a seed composition.
In some examples, the seed coating composition comprises a control agent which has antibacterial properties. In one embodiment, the control agent with antibacterial properties is selected from the compounds described herein elsewhere. In another embodiment, the compound is Streptomycin, oxytetracycline, oxolinic acid, or gentamicin. Other examples of antibacterial compounds which can be used as part of a seed coating composition include those based on dichlorophene and benzylalcohol hemi formal (Proxel® from ICI or Acticide® RS from Thor Chemie and Kathon® MK 25 from Rohm & Haas) and isothiazolinone derivatives such as alkylisothiazolinones and benzisothiazolinones (Acticide® MBS from Thor Chemie).
In some examples, growth regulator is selected from the group consisting of: Abscisic acid, amidochlor, ancymidol, 6-benzylaminopurine, brassinolide, butralin, chlormequat (chlormequat chloride), choline chloride, cyclanilide, daminozide, dikegulac, dimethipin, 2,6-dimethylpuridine, ethephon, flumetralin, flurprimidol, fluthiacet, forchlorfenuron, gibberellic acid, inabenfide, indole-3-acetic acid, maleic hydrazide, mefluidide, mepiquat (mepiquat chloride), naphthaleneacetic acid, N-6-benzyladenine, paclobutrazol, prohexadione phosphorotrithioate, 2,3,5-tri-iodobenzoic acid, trinexapac-ethyl and uniconazole. Additional non-limiting examples of growth regulators include brassinosteroids, cytokinines (e.g., kinetin and zeatin), auxins (e.g., indolylacetic acid and indolylacetyl aspartate), flavonoids and isoflavanoids (e.g., formononetin and diosmetin), phytoaixins (e.g., glyceolline), and phytoalexin-inducing oligosaccharides (e.g., pectin, chitin, chitosan, polygalacuronic acid, and oligogalacturonic acid), and gibellerins. Such agents are ideally compatible with the agricultural seed or seedling onto which the formulation is applied (e.g., it should not be deleterious to the growth or health of the plant). Furthermore, the agent is ideally one which does not cause safety concerns for human, animal or industrial use (e.g., no safety issues, or the compound is sufficiently labile that the commodity plant product derived from the plant contains negligible amounts of the compound).
Some examples of nematode-antagonistic biocontrol agents include ARF18; 30 Arthrobotrys spp.; Chaetomium spp.; Cylindrocarpon spp.; Exophilia spp.; Fusarium spp.; Gliocladium spp.; Hirsutella spp.; Lecanicillium spp.; Monacrosporium spp.; Myrothecium spp.; Neocosmospora spp.; Paecilomyces spp.; Pochonia spp.; Stagonospora spp.; vesicular- arbuscular mycorrhizal fungi, Burkholderia spp.; Pasteuria spp., Brevibacillus spp.; Pseudomonas spp.; and Rhizobacteria. Particularly preferred nematode-antagonistic biocontrol agents include ARF18, Arthrobotrys oligospora, Arthrobotrys dactyloides, Chaetomium globosum, Cylindrocarpon heteronema, Exophilia jeanselmei, Exophilia pisciphila, Fusarium aspergilus, Fusarium solani, Gliocladium catenulatum, Gliocladium roseum, Gliocladium vixens, Hirsutella rhossiliensis, Hirsutella minnesotensis, Lecanicillium lecanii, Monacrosporium drechsleri, Monacrosporium gephyropagum, Myrotehcium verrucaria, Neocosmospora vasinfecta, Paecilomyces lilacinus, Pochonia chlamydosporia, Stagonospora heteroderae, Stagonospora phaseoli, vesicular-arbuscular mycorrhizal fungi, Burkholderia cepacia, Pasteuria penetrans, Pasteuria thornei, Pasteuria nishizawae, Pasteuria ramosa, Pastrueia usage, Brevibacillus laterosporus strain G4, Pseudomonas fluorescens and Rhizobacteria.
Some examples of nutrients can be selected from the group consisting of a nitrogen fertilizer including, but not limited to Urea, Ammonium nitrate, Ammonium sulfate, Non-pressure nitrogen solutions, Aqua ammonia, Anhydrous ammonia, Ammonium thiosulfate, Sulfur-coated urea, Urea-formaldehydes, IBDU, Polymer-coated urea, Calcium nitrate, Ureaform, and Methylene urea, phosphorous fertilizers such as Diammonium phosphate, Monoammonium phosphate, Ammonium polyphosphate, Concentrated superphosphate and Triple superphosphate, and potassium fertilizers such as Potassium chloride, Potassium sulfate, Potassium-magnesium sulfate, Potassium nitrate. Such compositions can exist as free salts or ions within the seed coat composition. Alternatively, nutrients/fertilizers can be complexed or chelated to provide sustained release over time.
Some examples of rodenticides may include selected from the group of substances consisting of 2-isovalerylindan-1,3-dione, 4-(quinoxalin-2-ylamino) benzenesulfonamide, alpha-chlorohydrin, aluminum phosphide, antu, arsenous oxide, barium carbonate, bisthiosemi, brodifacoum, bromadiolone, bromethalin, calcium cyanide, chloralose, chlorophacinone, cholecalciferol, coumachlor, coumafuryl, coumatetralyl, crimidine, difenacoum, difethialone, diphacinone, ergocalciferol, flocoumafen, fluoroacetamide, flupropadine, flupropadine hydrochloride, hydrogen cyanide, iodomethane, lindane, magnesium phosphide, methyl bromide, norbormide, phosacetim, phosphine, phosphorus, pindone, potassium arsenite, pyrinuron, scilliroside, sodium arsenite, sodium cyanide, sodium fluoroacetate, strychnine, thallium sulfate, warfarin and zinc phosphide.
In the liquid form, for example, solutions or suspensions, bacterial populations can be mixed or suspended in water or in aqueous solutions. Suitable liquid diluents or carriers include water, aqueous solutions, petroleum distillates, or other liquid carriers.
Solid compositions can be prepared by dispersing the bacterial populations in and on an appropriately divided solid carrier, such as peat, wheat, bran, vermiculite, clay, talc, bentonite, diatomaceous earth, fuller's earth, pasteurized soil, and the like. When such formulations are used as wettable powders, biologically compatible dispersing agents such as non-ionic, anionic, amphoteric, or cationic dispersing and emulsifying agents can be used.
The solid carriers used upon formulation include, for example, mineral carriers such as kaolin clay, pyrophyllite, bentonite, montmorillonite, diatomaceous earth, acid white soil, vermiculite, and pearlite, and inorganic salts such as ammonium sulfate, ammonium phosphate, ammonium nitrate, urea, ammonium chloride, and calcium carbonate. Also, organic fine powders such as wheat flour, wheat bran, and rice bran may be used. The liquid carriers include vegetable oils such as soybean oil and cottonseed oil, glycerol, ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, etc.
Pests
Agricultural compositions of the disclosure, which may comprise any microbe taught herein, are sometimes combined with one or more pesticides.
The pesticides that are combined with the microbes of the disclosure may target any of the pests mentioned below.
“Pest” includes but is not limited to, insects, fungi, bacteria, nematodes, mites, ticks and the like. Insect pests include insects selected from the orders Coleoptera, Diptera, Hymenoptera, Lepidoptera, Mallophaga, Homoptera, Hemiptera Orthroptera, Thysanoptera, Dermaptera, Isoptera, Anoplura, Siphonaptera, Trichoptera, etc., particularly Lepidoptera and Coleoptera.
Those skilled in the art will recognize that not all compounds are equally effective against all pests. Compounds that may be combined with microbes of the disclosure may display activity against insect pests, which may include economically important agronomic, forest, greenhouse, nursery ornamentals, food and fiber, public and animal health, domestic and commercial structure, household and stored product pests.
As aforementioned, the agricultural compositions of the disclosure (which may comprise any microbe taught herein) are in embodiments combined with one or more pesticides. These pesticides may be active against any of the following pests:
Larvae of the order Lepidoptera include, but are not limited to, armyworms, cutworms, loopers and heliothines in the family Noctuidae Spodoptera frugiperda J E Smith (fall armyworm); S. exigua Hubner (beet armyworm); S. litura Fabricius (tobacco cutworm, cluster caterpillar); Mamestra configurata Walker (bertha armyworm); M. brassicae Linnaeus (cabbage moth); Agrotis Ipsilon Hufnagel (black cutworm); A. orthogonia Morrison (western cutworm); A. subterranea Fabricius (granulate cutworm); Alabama argillacea Hubner (cotton leaf worm); Trichoplusia ni Hubner (cabbage looper); Pseudoplusia includens Walker (soybean looper); Anticarsia gemmatalis Hubner (velvet bean caterpillar); Hypena scabra Fabricius (green clover worm); Heliothis virescens Fabricius (tobacco budworm); Pseudaletia unipuncta Haworth (armyworm); Athetis mindara Barnes and Mcdunnough (rough skinned cutworm); Euxoa messoria Harris (darksided cutworm); Earias insulana Boisduval (spiny bollworm); E. vittella Fabricius (spotted bollworm); Helicoverpa armigera Hubner (American bollworm); H. zea Boddie (corn earworm or cotton bollworm); Melanchra picta Harris (zebra caterpillar); Egira (Xylomyges) curialis Grote (citrus cutworm); borers, case bearers, webworms, coneworms, and skeletonizers from the family Pyralidae Ostrinia nubilalis Hubner (European corn borer); Amyelois transitella Walker (naval orangeworm); Anagasta kuehniella Zeller (Mediterranean flour moth); Cadra cautella Walker (almond moth); Chilo suppressalis Walker (rice stem borer); C. partellus, (sorghum borer); Corcyra cephalonica Stainton (rice moth); Crambus caliginosellus Clemens (corn root webworm); C. teterrellus Zincken (bluegrass webworm); Cnaphalocrocis medinalis Guenee (rice leaf roller); Desmia funeralis Hubner (grape leaffolder); Diaphania hyalinata Linnaeus (melon worm); D. nitidalis Stoll (pickleworm); Diatraea grandiosella Dyar (southwestern corn borer), D. saccharalis Fabricius (surgarcane borer); Eoreuma loftini Dyar (Mexican rice borer); Ephestia elutella Hubner (tobacco (cacao) moth); Galleria mellonella Linnaeus (greater wax moth); Herpetogramma licarsisalis Walker (sod webworm); Homoeosoma electellum Hulst (sunflower moth); Elasmopalpus lignosellus Zeller (lesser cornstalk borer); Achroia grisella Fabricius (lesser wax moth); Loxostege sticticalis Linnaeus (beet webworm); Orthaga thyrisalis Walker (tea tree web moth); Maruca testulalis Geyer (bean pod borer); Plodia interpunctella Hubner (Indian meal moth); Scirpophaga incertulas Walker (yellow stem borer); Udea rubigalis Guenee (celery leaftier); and leafrollers, budworms, seed worms and fruit worms in the family Tortricidae Acleris gloverana Walsingham (Western blackheaded budworm); A. variana Fernald (Eastern blackheaded budworm); Archips argyrospila Walker (fruit tree leaf roller); A. rosana Linnaeus (European leaf roller); and other Archips species, Adoxophyes orana Fischer von Rosslerstamm (summer fruit tortrix moth); Cochylis hospes Walsingham (banded sunflower moth); Cydia latiferreana Walsingham (filbertworm); C. pomonella Linnaeus (colding moth); Platynota flavedana Clemens (variegated leafroller); P. stultana Walsingham (omnivorous leafroller); Lobesia botrana Denis & Schiffermuller (European grape vine moth); Spilonota ocellana Denis & Schiffermuller (eyespotted bud moth); Endopiza viteana Clemens (grape berry moth); Eupoecilia ambiguella Hubner (vine moth); Bonagota salubricola Meyrick (Brazilian apple leafroller); Grapholita molesta Busck (oriental fruit moth); Suleima helianthana Riley (sunflower bud moth); Argyrotaenia spp.; Choristoneura spp.
Selected other agronomic pests in the order Lepidoptera include, but are not limited to, Alsophila pometaria Harris (fall cankerworm); Anarsia lineatella Zeller (peach twig borer); Anisota senatoria J. E. Smith (orange striped oakworm); Antheraea pernyi Guerin-Meneville (Chinese Oak Tussah Moth); Bombyx mori Linnaeus (Silkworm); Bucculatrix thurberiella Busck (cotton leaf perforator); Collas eurytheme Boisduval (alfalfa caterpillar); Datana integerrima Grote & Robinson (walnut caterpillar); Dendrolimus sibiricus Tschetwerikov (Siberian silk moth), Ennomos subsignaria Hubner (elm spanworm); Erannis tiliaria Harris (linden looper); Euproctis chrysorrhoea Linnaeus (browntail moth); Harrisina americana Guerin-Meneville (grapeleaf skeletonizer); Hemileuca oliviae Cockrell (range caterpillar); Hyphantria cunea Drury (fall web-worm); Keiferia lycopersicella Walsingham (tomato pinworm); Lambdina fiscellaria fiscellaria Hulst (Eastern hemlock looper); L. fiscellaria lugubrosa Hulst (Western hemlock looper); Leucoma salicis Linnaeus (satin moth); Lymantria dispar Linnaeus (gypsy moth); Manduca quinquemaculata Haworth (five spotted hawk moth, tomato hornworm); M. sexta Haworth (tomato homworm, tobacco hornworm); Operophtera brumata Linnaeus (winter moth); Paleacrita vernata Peck (spring cankerworm); Papilio cresphontes Cramer (giant swallowtail orange dog); Phryganidia californica Packard (California oakworm); Phyllocnistis citrella Stainton (citrus leafminer); Phyllonorycter blancardella Fabricius (spotted tentiform leafminer); Pieris brassicae Linnaeus (large white butterfly); P. rapae Linnaeus (small white butterfly); P. napi Linnaeus (green veined white butterfly); Platyptilia carduidactyla Riley (artichoke plume moth); Plutella xylostella Linnaeus (diamondback moth); Pectinophora gossypiella Saunders (pink bollworm); Pontia protodice Boisduval and Leconte (Southern cabbage-worm); Sabulodes aegrotata Guenee (onmivorous looper); Schizura concinna J. E. Smith (red humped caterpillar); Sitotroga cerealella Olivier (Angoumois grain moth); Thaumetopoea pityocampa Schiffermuller (pine processionary caterpillar); Tineola bisselliella Hummel (webbing clothes moth); Tuta absoluta Meyrick (tomato leafminer); Yponomeuta padella Linnaeus (ermine moth); Heliothis subjlexa Guenee; Malacosoma spp. and Orgyia spp.; Ostrinia nubilalis (European corn borer); seed corn maggot; Agrotis ipsilon (black cutworm).
Larvae and adults of the order Coleoptera including weevils from the families Anthribidae, Bruchidae and Curculionidae (including, but not limited to: Anthonomus grandis Boheman (boll weevil); Lissorhoptrus oryzophilus Kuschel (rice water weevil); Sitophilus granarius Linnaeus (granary weevil); S. oryzae Linnaeus (rice weevil); Hypera punctata Fabricius (clover leaf weevil); Cylindrocopturus adspersus LeConte (sunflower stem weevil); Smicronyx fulvus LeConte (red sunflower seed weevil); S. sordidus LeConte (gray sunflower seed weevil); Sphenophorus maidis Chittenden (maize billbug)); flea beetles, cucumber beetles, rootworms, leaf beetles, potato beetles and leafminers in the family Chrysomelidae (including, but not limited to: Leptinotarsa decemlineata Say (Colorado potato beetle); Diabrotica virgifera virgifera LeConte (western corn rootworm); D. barberi Smith and Lawrence (northern corn rootworm); D. undecimpunctata howardi Barber (southern corn rootworm); Chaetocnema pulicaria Melsheimer (corn flea beetle); Phyllotreta cruciferae Goeze (Crucifer flea beetle); Phyllotreta striolata (stripped flea beetle); Colaspis brunnea Fabricius (grape colaspis); Oulema melanopus Linnaeus (cereal leaf beetle); Zygogramma exclamationis Fabricius (sunflower beetle)); beetles from the family Coccinellidae (including, but not limited to: Epilachna varivestis Mulsant (Mexican bean beetle)); chafers and other beetles from the family Scarabaeidae (including, but not limited to: Popillia japonica Newman (Japanese beetle); Cyclocephala borealis Arrow (northern masked chafer, white grub); C. immaculata Olivier (southern masked chafer, white grub); Rhizotrogus majalis Razoumowsky (European chafer); Phyllophaga crinita Burmeister (white grub); Ligyrus gibbosus De Geer (carrot beetle)); carpet beetles from the family Dermestidae; wireworms from the family Elateridae, Eleodes spp., Melanotus spp.; Conoderus spp.; Limonius spp.; Agriotes spp.; Ctenicera spp.; Aeolus spp.; bark beetles from the family Scolytidae and beetles from the family Tenebrionidae; Cerotoma trifurcate (bean leaf beetle); and wireworm.
Adults and immatures of the order Diptera, including leafminers Agromyza parvicornis Loew (corn blotch leafminer); midges (including, but not limited to: Contarinia sorghicola Coquillett (sorghum midge); Mayetiola destructor Say (Hessian fly); Sitodiplosis mosellana Gehin (wheat midge); Neolasioptera murtfeldtiana Felt, (sunflower seed midge)); fruit flies (Tephritidae), Oscinella frit Linnaeus (fruit flies); maggots (including, but not limited to: Delia platura Meigen (seedcorn maggot); D. coarctata Fallen (wheat bulb fly) and other Delia spp., Meromyza americana Fitch (wheat stem maggot); Musca domestica Linnaeus (house flies); Fannia canicularis Linnaeus, F. femoralis Stein (lesser house flies); Stomoxys calcitrans Linnaeus (stable flies)); face flies, horn flies, blow flies, Chrysomya spp.; Phormia spp. and other muscoid fly pests, horse flies Tabanus spp.; bot flies Gastrophilus spp.; Oestrus spp.; cattle grubs Hypoderma spp.; deer flies Chrysops spp.; Melophagus ovinus Linnaeus (keds) and other Brachycera, mosquitoes Aedes spp.; Anopheles spp.; Culex spp.; black flies Prosimulium spp.; Simulium spp.; biting midges, sand flies, sciarids, and other Nematocera.
Adults and nymphs of the orders Hemiptera and Homoptera such as, but not limited to, adelgids from the family Adelgidae, plant bugs from the family Miridae, cicadas from the family Cicadidae, leafhoppers, Empoasca spp.; from the family Cicadellidae, planthoppers from the families Cixiidae, Flatidae, Fulgoroidea, Issidae and Delphacidae, treehoppers from the family Membracidae, psyllids from the family Psyllidae, whiteflies from the family Aleyrodidae, aphids from the family Aphididae, phylloxera from the family Phylloxeridae, mealybugs from the family Pseudococcidae, scales from the families Asterolecanidae, Coccidae, Dactylopiidae, Diaspididae, Eriococcidae Ortheziidae, Phoenicococcidae and Margarodidae, lace bugs from the family Tingidae, stink bugs from the family Pentatomidae, cinch bugs, Blissus spp.; and other seed bugs from the family Lygaeidae, spittlebugs from the family Cercopidae squash bugs from the family Coreidae and red bugs and cotton stainers from the family Pyrrhocoridae.
Agronomically important members from the order Homoptera further include, but are not limited to: Acyrthisiphon pisum Harris (pea aphid); Aphis craccivora Koch (cowpea aphid); A. fabae Scopoli (black bean aphid); A. gossypii Glover (cotton aphid, melon aphid); A. maidiradicis Forbes (corn root aphid); A. pomi De Geer (apple aphid); A. spiraecola Patch (spirea aphid); Aulacorthum solani Kaltenbach (foxglove aphid); Chaetosiphon fragaefolii Cockerell (strawberry aphid); Diuraphis noxia Kurdjumov/Mordvilko (Russian wheat aphid); Dysaphis plantaginea Paaserini (rosy apple aphid); Eriosoma lanigerum Hausmann (woolly apple aphid); Brevicoryne brassicae Linnaeus (cabbage aphid); Hyalopterus pruni Geoffroy (mealy plum aphid); Lipaphis erysimi Kaltenbach (turnip aphid); Metopolophium dirrhodum Walker (cereal aphid); Macrosiphum euphorbiae Thomas (potato aphid); Myzus persicae Sulzer (peach potato aphid, green peach aphid); Nasonovia ribisnigri Mosley (lettuce aphid); Pemphigus spp. (root aphids and gall aphids); Rhopalosiphum maidis Fitch (corn leaf aphid); R. padi Linnaeus (bird cherry-oat aphid); Schizaphis graminum Rondani (greenbug); Sipha flava Forbes (yellow sugarcane aphid); Sitobion avenae Fabricius (English grain aphid); Therioaphis maculata Buckton (spotted alfalfa aphid); Toxoptera aurantii Boyer de Fonscolombe (black citrus aphid) and T. citricida Kirkaldy (brown citrus aphid); Melanaphis sacchari (sugarcane aphid); Adelges spp. (adelgids); Phylloxera devastatrix Pergande (pecan phylloxera); Bemisia tabaci Gennadius (tobacco whitefly, sweetpotato whitefly); B. argentifolii Bellows & Perring (silverleaf whitefly); Dialeurodes citri Ashmead (citrus whitefly); Trialeurodes abutiloneus (bandedwinged whitefly) and T. vaporariorum Westwood (greenhouse whitefly); Empoasca fabae Harris (potato leafhopper); Laodelphax striatellus Fallen (smaller brown planthopper); Macrolestes quadrilineatus Forbes (aster leafhopper); Nephotettix cinticeps Uhler (green leafhopper); N. nigropictus Stal (rice leafhopper); Nilaparvata lugens Stal (brown planthopper); Peregrinus maidis Ashmead (corn planthopper); Sogatella furcifera Horvath (white backed planthopper); Sogatodes orizicola Muir (rice delphacid); Typhlocyba pomaria McAtee (white apple leafhopper); Erythroneoura spp. (grape leafhoppers); Magicicada septendecim Linnaeus (periodical cicada); Icerya purchasi Maskell (cottony cushion scale); Quadraspidiotus perniciosus Comstock (San Jose scale); Planococcus citri Risso (citrus mealybug); Pseudococcus spp. (other mealybug complex); Cacopsylla pyricola Foerster (pear psylla); Trioza diospyri Ashmead (persimmon psylla).
Species from the order Hemiptera include, but are not limited to: Acrosternum hilare Say (green stink bug); Anasa tristis De Geer (squash bug); Blissus leucopterus leucopterus Say (chinch bug); Corythuca gossypii Fabricius (cotton lace bug); Cyrtopeltis modesta Distant (tomato bug); Dysdercus suturellus Herrich-Schaffer (cotton stainer); Euschistus servus Say (brown stink bug); E. variolarius Palisot de Beauvais (one spotted stink bug); Graptostethus spp. (complex of seed bugs); Leptoglossus corculus Say (leaf footed pine seed bug); Lygus lineolaris Palisot de Beauvais (tarnished plant bug); L. Hesperus Knight (Western tarnished plant bug); L. pratensis Linnaeus (common meadow bug); L. rugulipennis Poppius (European tarnished plant bug); Lygocoris pabulinus Linnaeus (common green capsid); Nezara viridula Linnaeus (southern green stink bug); Oebalus pugnax Fabricius (rice stink bug); Oncopeltus fasciatus Dallas (large milk-weed bug); Pseudatomoscelis seriatus Reuter (cotton flea hopper).
Hemiptera such as, Calocoris norvegicus Gmelin (strawberry bug); Orthops campestris Linnaeus; Plesiocoris rugicollis Fallen (apple capsid); Cyrtopeltis modestus Distant (tomato bug); Cyrtopeltis notatus Distant (suckfly); Spanagonicus albofasciatus Reuter (whitemarked fleahopper); Diaphnocoris chlorionis Say (honeylocust plant bug); Labopidicola allii Knight (onion plant bug); Pseudatomoscelis seriatus Reuter (cotton fleahopper); Adelphocoris rapidus Say (rapid plant bug); Poecilocapsus lineatus Fabricius (four lined plant bug); Nysius ericae Schilling (false chinch bug); Nysius raphanus Howard (false chinch bug); Nezara viridula Linnaeus (Southern green stink bug); Eurygaster spp.; Coreidae spp.; Pyrrhocoridae spp.; Tinidae spp.; Blostomatidae spp.; Reduviidae spp. and Cimicidae spp.
Adults and larvae of the order Acari (mites) such as Aceria tosichella Keifer (wheat curl mite); Petrobia latens Muller (brown wheat mite); spider mites and red mites in the family Tetranychidae, Panonychus ulmi Koch (European red mite); Tetranychus urticae Koch (two spotted spider mite); (T. mcdanieli McGregor (McDaniel mite); T. cinnabarinus Boisduval (carmine spider mite); T. turkestani Ugarov & Nikolski (strawberry spider mite); flat mites in the family Tenuipalpidae, Brevipalpus lewisi McGregor (citrus flat mite); rust and bud mites in the family Eriophyidae and other foliar feeding mites and mites important in human and animal health, i.e., dust mites in the family Epidermoptidae, follicle mites in the family Demodicidae, grain mites in the family Glycyphagidae, ticks in the order Ixodidae. Ixodes scapularis Say (deer tick); I. holocyclus Neumann (Australian paralysis tick); Dermacentor variabilis Say (American dog tick); Amblyomma americanum Linnaeus (lone star tick) and scab and itch mites in the families Psoroptidae, Pyemotidae and Sarcoptidae.
Insect pests of the order Thysanura, such as Lepisma saccharina Linnaeus (silverfish); Thermobia domestica Packard (firebrat).
Additional arthropod pests include: spiders in the order Araneae such as Loxosceles reclusa Gertsch and Mulaik (brown recluse spider) and the Latrodectus mactans Fabricius (black widow spider) and centipedes in the order Scutigeromorpha such as Scutigera coleoptrata Linnaeus (house centipede).
Superfamily of stink bugs and other related insects including but not limited to species belonging to the family Pentatomidae (Nezara viridula, Halyomorpha halys, Piezodorus guildini, Euschistus servus, Acrostemum hilare, Euschistus heros, Euschistus tristigmus, Acrosternum hilare, Dichelops furcatus, Dichelops melacanthus, and Bagrada hilaris (Bagrada Bug)), the family Plataspidae (Megacopta cribraria-Bean plataspid) and the family Cydnidae (Scaptocoris castanea-Root stink bug) and Lepidoptera species including but not limited to: diamond-back moth, e.g., Helicoverpa zea Boddie; soybean looper, e.g., Pseudoplusia includens Walker and velvet bean caterpillar e.g., Anticarsia gemmatalis Hubner.
Nematodes include parasitic nematodes such as root-knot, cyst and lesion nematodes, including Heterodera spp., Meloidogyne spp. and Globodera spp.; particularly members of the cyst nematodes, including, but not limited to, Heterodera glycines (soybean cyst nematode); Heterodera schachtii (beet cyst nematode); Heterodera avenae (cereal cyst nematode) and Globodera rostochiensis and Globodera pailida (potato cyst nematodes). Lesion nematodes include Pratylenchus spp.
Pesticidal Compositions Comprising a Pesticide and Microbe of the Disclosure
As aforementioned, agricultural compositions of the disclosure, which may comprise any microbe taught herein, are sometimes combined with one or more pesticides. Pesticides can include herbicides, insecticides, fungicides, nematicides, etc.
In some embodiments, the pesticides/microbial combinations can be applied in the form of compositions and can be applied to the crop area or plant to be treated, simultaneously or in succession, with other compounds. These compounds can be fertilizers, weed killers, cryoprotectants, surfactants, detergents, pesticidal soaps, dormant oils, polymers, and/or time release or biodegradable carrier formulations that permit long term dosing of a target area following a single application of the formulation. They can also be selective herbicides, chemical insecticides, virucides, microbicides, amoebicides, pesticides, fungicides, bacteriocides, nematicides, molluscicides or mixtures of several of these preparations, if desired, together with further agriculturally acceptable carriers, surfactants or application promoting adjuvants customarily employed in the art of formulation. Suitable carriers (i.e. agriculturally acceptable carriers) and adjuvants can be solid or liquid and correspond to the substances ordinarily employed in formulation technology, e.g. natural or regenerated mineral substances, solvents, dispersants, wetting agents, sticking agents, tackifiers, binders or fertilizers. Likewise, the formulations may be prepared into edible baits or fashioned into pest traps to permit feeding or ingestion by a target pest of the pesticidal formulation.
Exemplary chemical compositions, which may be combined with the microbes of the disclosure, include:
Fruits/Vegetables Herbicides: Atrazine, Bromacil, Diuron, Glyphosate, Linuron, Metribuzin, Simazine, Trifluralin, Fluazifop, Glufosinate, Halo sulfuron Gowan, Paraquat, Propyzamide, Sethoxydim, Butafenacil, Halosulfuron, Indaziflam; Fruits/Vegetables Insecticides: Aldicarb, Bacillus thuringiensis, Carbaryl, Carbofuran, Chlorpyrifos, Cypermethrin, Deltamethrin, Diazinon, Malathion, Abamectin, Cyfluthrin/betacyfluthrin, Esfenvalerate, Lambda-cyhalothrin, Acequinocyl, Bifenazate, Methoxyfenozide, Novaluron, Chromafenozide, Thiacloprid, Dinotefuran, FluaCrypyrim, Tolfenpyrad, Clothianidin, Spirodiclofen, Gamma-cyhalothrin, Spiromesifen, Spinosad, Rynaxypyr, Cyazypyr, Spinoteram, Triflumuron, Spirotetramat, Imidacloprid, Flubendiamide, Thiodicarb, Metaflumizone, Sulfoxaflor, Cyflumetofen, Cyanopyrafen, Imidacloprid, Clothianidin, Thiamethoxam, Spinotoram, Thiodicarb, Flonicamid, Methiocarb, Emamectin benzoate, Indoxacarb, Forthiazate, Fenamiphos, Cadusaphos, Pyriproxifen, Fenbutatin oxide, Hexthiazox, Methomyl, 4-[[(6-Chlorpyridin-3-yl)methyl](2, 2-difluorethyl)amino]furan-2(5H)-on; Fruits Vegetables Fungicides: Carbendazim, Chlorothalonil, EBDCs, Sulphur, Thiophanate-methyl, Azoxystrobin, Cymoxanil, Fluazinam, Fosetyl, Iprodione, Kresoxim-methyl, Metalaxyl/mefenoxam, Trifloxystrobin, Ethaboxam, Iprovalicarb, Trifloxystrobin, Fenhexamid, Oxpoconazole fumarate, Cyazofamid, Fenamidone, Zoxamide, Picoxystrobin, Pyraclostrobin, Cyflufenamid, Boscalid;
Cereals Herbicides: Isoproturon, Bromoxynil, loxynil, Phenoxies, Chlorsulfuron, Clodinafop, Diclofop, Diflufenican, Fenoxaprop, Florasulam, Fluoroxypyr, Metsulfuron, Triasulfuron, Flucarbazone, lodosulfuron, Propoxycarbazone, Picolin-afen, Mesosulfuron, Beflubutamid, Pinoxaden, Amidosulfuron, Thifensulfuron Methyl, Tribenuron, Flupyrsulfuron, Sulfosulfuron, Pyrasulfotole, Pyroxsulam, Flufenacet, Tralkoxydim, Pyroxasulfon; Cereals Fungicides: Carbendazim, Chlorothalonil, Azoxystrobin, Cyproconazole, Cyprodinil, Fenpropimorph, Epoxiconazole, Kresoxim-methyl, Quinoxyfen, Tebuconazole, Trifloxystrobin, Simeconazole, Picoxystrobin, Pyraclostrobin, Dimoxystrobin, Prothioconazole, Fluoxastrobin; Cereals Insecticides: Dimethoate, Lambda-cyhalothrin, Deltamethrin, alpha-Cypermethrin, β-cyfluthrin, Bifenthrin, Imidacloprid, Clothianidin, Thiamethoxam, Thiacloprid, Acetamiprid, Dinetofuran, Clorphyriphos, Metamidophos, Oxidemethon methyl, Pirimicarb, Methiocarb;
Maize Herbicides: Atrazine, Alachlor, Bromoxynil, Acetochlor, Dicamba, Clopyralid, S-Dimethenamid, Glufosinate, Glyphosate, Isoxaflutole, S-Metolachlor, Mesotrione, Nicosulfuron, Primisulfuron, Rimsulfuron, Sulcotrione, Foramsulfuron, Topramezone, Tembotrione, Saflufenacil, Thiencarbazone, Flufenacet, Pyroxasulfon; Maize Insecticides: Carbofuran, Chlorpyrifos, Bifenthrin, Fipronil, Imidacloprid, Lambda-Cyhalothrin, Tefluthrin, Terbufos, Thiamethoxam, Clothianidin, Spiromesifen, Flubendiamide, Triflumuron, Rynaxypyr, Deltamethrin, Thiodicarb, 3-Cyfluthrin, Cypermethrin, Bifenthrin, Lufenuron, Triflumoron, Tefluthrin, Tebupirim-phos, Ethiprole, Cyazypyr, Thiacloprid, Acetamiprid, Dinetofuran, Avermectin, Methiocarb, Spirodiclofen, Spirotetramat; Maize Fungicides: Fenitropan, Thiram, Prothioconazole, Tebuconazole, Trifloxystrobin;
Rice Herbicides: Butachlor, Propanil, Azimsulfuron, Bensulfuron, Cyhalo-fop, Daimuron, Fentrazamide, Imazosulfuron, Mefenacet, Oxaziclomefone, Pyrazosulfuron, Pyributicarb, Quinclorac, Thiobencarb, Indanofan, Flufenacet, Fentrazamide, Halosulfuron, Oxaziclomefone, Benzobicyclon, Pyriftalid, Penoxsulam, Bispyribac, Oxadiargyl, Ethoxysulfuron, Pretilachlor, Mesotrione, Tefuryltrione, Oxadiazone, Fenoxaprop, Pyrimisulfan; Rice Insecticides: Diazinon, Fenitro-thion, Fenobucarb, Monocrotophos, Benfuracarb, Buprofezin, Dinotefuran, Fipronil, Imidacloprid, Isoprocarb, Thiacloprid, Chromafenozide, Thiacloprid, Dinotefuran, Clothianidin, Ethiprole, Flubendiamide, Rynaxypyr, Deltamethrin, Acetamiprid, Thiamethoxam, Cyazypyr, Spinosad, Spinotoram, Emamectin-Benzoate, Cypermethrin, Chlorpyriphos, Caftap, Methamidophos, Etofen-prox, Triazophos, [(6-Chlorpyridin-3-yl)methyl] (2,2-difluorethyl)amino]furan-2(5H)-on, Carbofuran, Benfuracarb; Rice Fungicides: Thiophanate-methyl, Azoxystrobin, Carpropamid, Edifenphos, Ferimzone, Iprobenfos, Isoprothiolane, Pencycuron, Probenazole, Pyroquilon, Tricyclazole, Trifloxystrobin, Diclocymet, Fenoxanil, Simeconazole, Tiadinil;
Cotton Herbicides: Diuron, Fluometuron, MSMA, Oxyfluorfen, Prometryn, Trifluralin, Carfentrazone, Clethodim, Fluazifop-butyl, Glyphosate, Norflurazon, Pendimethalin, Pyrithiobac-sodium, Trifloxysulfuron, Tepraloxydim, Glufosinate, Flumioxazin, Thidiazuron; Cotton Insecticides: Acephate, Aldicarb, Chlorpyrifos, Cypermethrin, Deltamethrin, Malathion, Monocrotophos, Abamectin, Acetamiprid, Emamectin Benzoate, Imidacloprid, Indoxacarb, Lambda-Cyhalothrin, Spinosad, Thiodicarb, Gamma-Cyhalothrin, Spiromesifen, Pyridalyl, Flonicamid, Flubendiamide, Triflumuron, Rynaxypyr, Beta-Cyfluthrin, Spirotetramat, Clothianidin, Thiamethoxam, Thiacloprid, Dinetofuran, Flubendiamide, Cyazypyr, Spinosad, Spinotoram, gamma Cyhalothrin, 4-[[(6-Chlorpyridin-3-yl) methyl](2,2-difluorethyl)aminolfuran-2(5H)-on, Thiodicarb, Avermectin, Flonicamid, Pyridalyl, Spiromesifen, Sulfoxaflor, Profenophos, Thriazophos, Endosulfan; Cotton Fungicides: Etridiazole, Metalaxyl, Quintozene;
Soybean Herbicides: Alachlor, Bentazone, Trifluralin, Chlorimuron-Ethyl, Cloransulam-Methyl, Fenoxaprop, Fomesafen, Flu-azifop, Glyphosate, Imazamox, Imazaquin, Imazethapyr, (S-)Metolachlor, Metribuzin, Pendimethalin, Tepraloxydim, Glufosinate; Soybean Insecticides: Lambda-cyhalothrin, Methomyl, Parathion, Thiocarb, Imidacloprid, Clothianidin, Thiamethoxam, Thiacloprid, Acetamiprid, Dinetofuran, Flubendiamide, Rynaxypyr, Cyazypyr, Spinosad, Spinotoram, Emamectin-Benzoate, Fipronil, Ethiprole, Deltamethrin, β-Cyfluthrin, gamma and lambda Cyhalothrin, 4-[[(6-Chlorpyridin-3-y l)methyl] (2,2-difluorethyl)amino]furan-2(5H)-on, Spirotetramat, Spinodiclofen, Triflumuron, Flonicamid, Thiodicarb, beta-Cyfluthrin; Soybean Fungicides: Azoxystrobin, Cyproconazole, Epoxiconazole, Flutriafol, Pyraclostrobin, Tebuconazole, Trifloxystrobin, Prothioconazole, Tetraconazole;
Sugarbeet Herbicides: Chloridazon, Desmedipham, Ethofumesate, Phenmedipham, Triallate, Clopyralid, Fluazifop, Lenacil, Metamitron, Quinmerac, Cycloxydim, Triflusulfuron, Tepral-oxydim, Quizalofop; Sugarbeet Insecticides: Imidacloprid, Clothianidin, Thiamethoxam, Thiacloprid, Acetamiprid, Dinetofuran, Deltamethrin, β-Cyfluthrin, gamma/lambda Cyhalothrin, 4-[[(6-Chlorpyridin-3-yl)methyl](2,2-difluor-ethyl)amino]furan-2(5H)-on, Tefluthrin, Rynaxypyr, Cyaxypyr, Fipronil, Carbofuran;
Canola Herbicides: Clopyralid, Diclofop, Fluazifop, Glufosinate, Glyphosate, Metazachlor, Trifluralin Ethametsulfuron, Quinmerac, Quizalofop, Clethodim, Tepraloxydim; Canola Fungicides: Azoxystrobin, Carbendazim, Fludioxonil, Iprodione, Prochloraz, Vinclozolin; Canola Insecticides: Carbofuran organophos-phates, Pyrethroids, Thiacloprid, Deltamethrin, Imidacloprid, Clothianidin, Thiamethoxam, Acetamiprid, Dineto-furan, β-Cyfluthrin, gamma and lambda Cyhalothrin, tau-Fluvaleriate, Ethiprole, Spinosad, Spinotoram, Flubendiamide, Rynaxypyr, Cyazypyr, 4-[[(6-Chlorpyridin-3-yl)methyl] (2,2-difluorethy)amino] furan-2(5H)-on.
Insecticidal Compositions Comprising an Insecticide and Microbe of the Disclosure
As aforementioned, agricultural compositions of the disclosure, which may comprise any microbe taught herein, are sometimes combined with one or more insecticides.
In some embodiments, insecticidal compositions may be included in the compositions set forth herein, and can be applied to a plant(s) or a part(s) thereof simultaneously or in succession, with other compounds. Insecticides include ammonium carbonate, aqueous potassium silicate, boric acid, copper sulfate, elemental sulfur, lime sulfur, sucrose octanoate esters, 4-[[(6-Chlorpyridin-3-yl)methyl](2, 2-difluorethyl)amino]furan-2(5H)-on, abamectin, notenone, fenazaquin, fenpyroximate, pyridaben, pyrimedifen, tebufenpyrad, tolfenpyrad, acephate, emamectin benzoate, lepimectin, milbemectin, hdroprene, kinoprene, methoprene, fenoxycarb, pyriproxyfen, methryl bromide and other alkyl halides, fulfuryl fluoride, chloropicrin, borax, disodium octaborate, sodium borate, sodium metaborate, tartar emetic, dazomet, metam, pymetrozine, pyrifluquinazon, flofentezine, diflovidazin, hexythiazox, bifenazate, thiamethoxam, imidacloprid, fenpyroximate, azadirachtin, permethrin, esfenvalerate, acetamiprid, bifenthrin, indoxacarb, azadirachtin, pyrethrin, imidacloprid, beta-cyfluthrin, sulfotep, tebupirimfos, temephos, terbufos, tetrachlorvinphos, thiometon, triazophos, alanycarb, aldicarb, bendiocarb, benfluracarb, butocarboxim, butoxycarboxim, carbaryl, carbofuran, carbosulfan, ethiofencarb, fenobucarb, formetanate, furathiocarb, isoprocarb, methiocarb, methymyl, metolcarb, oxamyl, primicarb, propoxur, thiodicarb, thiofanox, triazamate, trimethacarb, XMC, xylylcarb, acephate, azamethiphos, azinphos-ethyl, azinphos-methyl, cadusafos, chlorethoxyfox, trichlorfon, vamidothion, chlordane, endosulfan, ethiprole, fipronil, acrinathrin, allethrin, bifenthrin, bioallethrin, bioalletherin X-cyclopentenyl, bioresmethrin, cyclorothrin, cyfluthrin, cyhalothrin, cypermethrin, cyphenothrin [(1R)-trans-isomers], deltamethrin, empenthrin [(EZ)-(1R)-isomers], esfenvalerate, etofenprox, fenpropathrin, fenvalerate, flucythrinate, flumethrin, halfenprox, kadathrin, phenothrin [(1R)-trans-isomer] prallethrin, pyrethrins (pyrethrum), resmethrin, silafluofen, tefluthrin, tetramethrin, tetramethrin [(1R)-isomers], tralomethrin, transfluthrin, alpha-cypermethrin, beta-cyfluthrin, beta-cypermethrin, d-cis-trans allethrin, d-trans allethrin, gamma-cyhalothrin, lamda-cyhalothrin, tau-fluvalinate, theta-cypermethrin, zeta-cypermethrin, methoxychlor, nicotine, sulfoxaflor, acetamiprid, clothianidin, dinotefuran, imidacloprid, nitenpyram, thiacloprid, thiamethoxan, tebuprimphos, beta-cyfluthrin, clothianidin, flonicamid, hydramethylnon, amitraz, flubendiamide, blorantraniliprole, lambda cyhalothrin, spinosad, gamma cyhalothrin, Beauveria bassiana, capsicum oleoresin extract, garlic oil, carbaryl, chlorpyrifos, sulfoxaflor, lambda cyhalothrin, Chlorfenvinphos, Chlormephos, Chlorpyrifos, Chlorpyrifos-methyl, Coumaphos, Cyanophos, Demeton-S-methyl, Diazinon, Dichlorvos/DDVP, Dicrotophos, Dimethoate, Dimethylvinphos, Disulfoton, EPN, Ethion, Ethoprophos, Famphur, Fenamiphos, Fenitrothion, Fenthion, Fosthiazate, Heptenophos, Imicyafos, Isofenphos, Isopropyl O-(methoxyaminothio-phosphoryl) salicylate, Isoxathion, Malathion, Mecarbam, Methamidophos, Methidathion, Mevinphos, Monocrotophos, Naled, Omethoate, Oxydemeton-methyl, Parathion, Parathion-methyl, Phenthoate, Phorate, Phosalone, Phosmet, Phosphamidon, Phoxim, Pirimiphos-methyl, Profenofos, Propetamphos, Prothiofos, Pyraclofos, Pyridaphenthion, Quinalphosfluacrypyrim, tebufenozide, chlorantraniliprole, Bacillus thuringiensis subs. Kurstaki, terbufos, mineral oil, fenpropathrin, metaldehyde, deltamethrin, diazinon, dimethoate, diflubenzuron, pyriproxyfen, reosemary oil, peppermint oil, geraniol, azadirachtin, piperonyl butoxide, cyantraniliprole, alpha cypermethrin, tefluthrin, pymetrozine, malathion, Bacillus thuringiensis subsp. israelensis, dicofol, bromopropylate, benzoximate, azadirachtin, flonicamid, soybean oil, Chromobacterium subtsugae strain PRAA4-1, zeta cypermethrin, phosmet, methoxyfenozide, paraffinic oil, spirotetramat, methomyl, Metarhizium anisopliae strain F52, ethoprop, tetradifon, propargite, fenbutatin oxide, azocyclotin, cyhexatin, diafenthiuron, Bacillus sphaericus, etoxazole, flupyradifurone, azadirachtin, Beauveria bassiana, cyflumetofen, azadirachtin, chinomethionat, acephate, Isaria fumosorosea Apopka strain 97, sodium tetraborohydrate decahydrate, emamectin benzoate, cryolite, spinetoram, Chenopodium ambrosioides extract, novaluron, dinotefuran, carbaryl, acequinocyl, flupyradifurone, iron phosphate, kaolin, buprofezin, cyromazine, chromafenozide, halofenozide, methoxyfenozide, tebufenozide, bistrifluron, chlorfluazuron, diflubenzuron, flucycloxuron, flufenoxuron, hexaflumuron, lufenuron, nocaluron, noviflumuron, teflubenzuron, triflumuron, bensultap, cartap hydrochloride, thiocyclam, thiosultap-sodium, DNOC, chlorfenapyr, sulfuramid, phorate, tolfenpyrad, sulfoxaflor, neem oil, Bacillus thuringiensis subsp. tenebrionis strain SA-10, cyromazine, heat-killed Burkholderia spp., cyantraniliprole, cyenopyrafen, cyflumetofen, sodium cyanide, potassium cyanide, calcium cyanide, aluminum phosphide, calcium phosphide, phosphine, zinc phosphide, spriodiclofen, spiromesifen, spirotetramat, metaflumizone, flubendiamide, pyflubumide, oxamyl, Bacillus thuringiensis subsp. aizawai, etoxazole, and esfenvalerate.
Bacillus
thuringiensis and
israelensis, Bt var. kurstaki, Bt
Bacillus
Bacillus
sphaericus
sphaericus
Insecticides also include synergists or activators that are not in themselves considered toxic or insecticidal, but are materials used with insecticides to synergize or enhance the activity of the insecticides. Syngergists or activators include piperonyl butoxide.
Insecticides can be biorational, or can also be known as biopesticides or biological pesticides. Biorational refers to any substance of natural origin (or man-made substances resembling those of natural origin) that has a detrimental or lethal effect on specific target pest(s), e.g., insects, weeds, plant diseases (including nematodes), and vertebrate pests, possess a unique mode of action, are non-toxic to man, domestic plants and animals, and have little or no adverse effects on wildlife and the environment.
Biorational insecticides (or biopesticides or biological pesticides) can be grouped as: (1) biochemicals (hormones, enzymes, pheromones and natural agents, such as insect and plant growth regulators), (2) microbial (viruses, bacteria, fungi, protozoa, and nematodes), or (3) Plant-Incorporated protectants (PIPs)—primarily transgenic plants, e.g., Bt corn.
Biopesticides, or biological pesticides, can broadly include agents manufactured from living microorganisms or a natural product and sold for the control of plant pests. Biopesticides can be: microorganisms, biochemicals, and semiochemicals. Biopesticides can also include peptides, proteins and nucleic acids such as double-stranded DNA, single-stranded DNA, double-stranded RNA, single-stranded RNA and hairpin DNA or RNA.
Bacteria, fungi, oomycetes, viruses and protozoa are all used for the biological control of insect pests. The most widely used microbial biopesticide is the insect pathogenic bacteria Bacillus thuringiensis (Bt), which produces a protein crystal (the Bt δ-endotoxin) during bacterial spore formation that is capable of causing lysis of gut cells when consumed by susceptible insects. Microbial Bt biopesticides consist of bacterial spores and δ-endotoxin crystals mass-produced in fermentation tanks and formulated as a sprayable product. Bt does not harm vertebrates and is safe to people, beneficial organisms and the environment. Thus, Bt sprays are a growing tactic for pest management on fruit and vegetable crops where their high level of selectivity and safety are considered desirable, and where resistance to synthetic chemical insecticides is a problem. Bt sprays have also been used on commodity crops such as maize, soybean and cotton, but with the advent of genetic modification of plants, farmers are increasingly growing Bt transgenic crop varieties.
Other microbial insecticides include products based on entomopathogenic baculoviruses. Baculoviruses that are pathogenic to arthropods belong to the virus family and possess large circular, covalently closed, and double-stranded DNA genomes that are packaged into nucleocapsids. More than 700 baculoviruses have been identified from insects of the orders Lepidoptera, Hymenoptera, and Diptera. Baculoviruses are usually highly specific to their host insects and thus, are safe to the environment, humans, other plants, and beneficial organisms. Over 50 baculovirus products have been used to control different insect pests worldwide. In the US and Europe, the Cydia pomonella granulovirus (CpGV) is used as an inundative biopesticide against codlingmoth on apples. Washington State, as the biggest apple producer in the US, uses CpGV on 13% of the apple crop. In Brazil, the nucleopolyhedrovirus of the soybean caterpillar Anticarsia gemmatalis was used on up to 4 million ha (approximately 35%) of the soybean crop in the mid-1990s. Viruses such as Gemstar® (Certis USA) are available to control larvae of Heliothis and Helicoverpa species.
At least 170 different biopesticide products based on entomopathogenic fungi have been developed for use against at least five insect and acarine orders in glasshouse crops, fruit and field vegetables as well as commodity crops. The majority of products are based on the ascomycetes Beauveria bassiana or Metarhizium anisopliae. M anisopliae has also been developed for the control of locust and grasshopper pests in Africa and Australia and is recommended by the Food and Agriculture Organization of the United Nations (FAO) for locust management.
A number of microbial pesticides registered in the United States are listed in Table 16 of Kabaluk et al. 2010 (Kabaluk, J. T. et al. (ed.). 2010. The Use and Regulation of Microbial Pesticides in Representative Jurisdictions Worldwide. IOBC Global. 99pp.) and microbial pesticides registered in selected countries are listed in Annex 4 of Hoeschle-Zeledon et al. 2013 (Hoeschle-Zeledon, I., P. Neuenschwander and L. Kumar. (2013). Regulatory Challenges for biological control. SP-IPM Secretariat, International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria. 43 pp.), each of which is incorporated herein in its entirety.
Plants produce a wide variety of secondary metabolites that deter herbivores from feeding on them. Some of these can be used as biopesticides. They include, for example, pyrethrins, which are fast-acting insecticidal compounds produced by Chrysanthemum cinerariaefolium. They have low mammalian toxicity but degrade rapidly after application. This short persistence prompted the development of synthetic pyrethrins (pyrethroids). The most widely used botanical compound is neem oil, an insecticidal chemical extracted from seeds of Azadirachta indica. Two highly active pesticides are available based on secondary metabolites synthesized by soil actinomycetes, but they have been evaluated by regulatory authorities as if they were synthetic chemical pesticides. Spinosad is a mixture of two macrolide compounds from Saccharopolyspora spinosa. It has a very low mammalian toxicity and residues degrade rapidly in the field. Farmers and growers used it widely following its introduction in 1997 but resistance has already developed in some important pests such as western flower thrips. Abamectin is a macrocyclic lactone compound produced by Streptomyces avermitilis. It is active against a range of pest species but resistance has developed to it also, for example, in tetranychid mites.
Peptides and proteins from a number of organisms have been found to possess pesticidal properties. Perhaps most prominent are peptides from spider venom (King, G. F. and Hardy, M. C. (2013) Spider-venom peptides: structure, pharmacology, and potential for control of insect pests. Annu. Rev. Entomol. 58: 475-496). A unique arrangement of disulfide bonds in spider venom peptides render them extremely resistant to proteases. As a result, these peptides are highly stable in the insect gut and hemolymph and many of them are orally active. The peptides target a wide range of receptors and ion channels in the insect nervous system. Other examples of insecticidal peptides include: sea anemone venom that act on voltage-gated Na+channels (Bosmans, F. and Tytgat, J. (2007) Sea anemone venom as a source of insecticidal peptides acting on voltage-gated Na+ channels. Toxicon. 49(4): 550-560); the PA1b (Pea Albumin 1, subunit b) peptide from Legume seeds with lethal activity on several insect pests, such as mosquitoes, some aphids and cereal weevils (Eyraud, V. et al. (2013) Expression and Biological Activity of the Cystine Knot Bioinsecticide PA1b (Pea Albumin 1 Subunit b). PLoS ONE 8(12): e81619); and an internal 10 kDa peptide generated by enzymatic hydrolysis of Canavalia ensiformis (jack bean) urease within susceptible insects (Martinelli, A. H. S., et al. (2014) Structure—function studies on jaburetox, a recombinant insecticidal peptide derived from jack bean (Canavalia ensiformis) urease. Biochimica et Biophysica Acta 1840: 935-944). Examples of commercially available peptide insecticides include Spear™-T for the treatment of thrips in vegetables and ornamentals in greenhouses, Spear™-P to control the Colorado Potato Beetle, and Spear™-C to protect crops from lepidopteran pests (Vestaron Corporation, Kalamazoo, Mich.). A novel insecticidal protein from Bacillus bombysepticus, called parasporal crystal toxin (PC), shows oral pathogenic activity and lethality towards silkworms and Cry1Ac-resistant Helicoverpa armigera strains (Lin, P. et al. (2015) PC, a novel oral insecticidal toxin from Bacillus bombysepticus involved in host lethality via APN and BtR-175. Sci. Rep. 5: 11101).
A semiochemical is a chemical signal produced by one organism that causes a behavioral change in an individual of the same or a different species. The most widely used semiochemicals for crop protection are insect sex pheromones, some of which can now be synthesized and are used for monitoring or pest control by mass trapping, lure-and-kill systems and mating disruption. Worldwide, mating disruption is used on over 660,000 ha and has been particularly useful in orchard crops.
As used herein, “transgenic insecticidal trait” refers to a trait exhibited by a plant that has been genetically engineered to express a nucleic acid or polypeptide that is detrimental to one or more pests. In one embodiment, the plants of the present disclosure are resistant to attach and/or infestation from any one or more of the pests of the present disclosure. In one embodiment, the trait comprises the expression of vegetative insecticidal proteins (VIPs) from Bacillus thuringiensis, lectins and proteinase inhibitors from plants, terpenoids, cholesterol oxidases from Streptomyces spp., insect chitinases and fungal chitinolytic enzymes, bacterial insecticidal proteins and early recognition resistance genes. In another embodiment, the trait comprises the expression of a Bacillus thuringiensis protein that is toxic to a pest. In one embodiment, the Bt protein is a Cry protein (crystal protein). Bt crops include Bt corn, Bt cotton and Bt soy. Bt toxins can be from the Cry family (see, for example, Crickmore et al., 1998, Microbiol. Mol. Biol. Rev. 62: 807-812), which are particularly effective against Lepidoptera, Coleoptera and Diptera.
Bt Cry and Cyt toxins belong to a class of bacterial toxins known as pore-forming toxins (PFT) that are secreted as water-soluble proteins undergoing conformational changes in order to insert into, or to translocate across, cell membranes of their host. There are two main groups of PFT: (i) the α-helical toxins, in which α-helix regions form the trans-membrane pore, and (ii) the β-barrel toxins, that insert into the membrane by forming a β-barrel composed of βsheet hairpins from each monomer. See, Parker M W, Feil S C, “Pore-forming protein toxins: from structure to function,” Prog. Biophys. Mol. Biol. 2005 May; 88(1):91-142. The first class of PFT includes toxins such as the colicins, exotoxin A, diphtheria toxin and also the Cry three-domain toxins. On the other hand, aerolysin, α-hemolysin, anthrax protective antigen, cholesterol-dependent toxins as the perfringolysin O and the Cyt toxins belong to the β-barrel toxins. Id. In general, PFT producing-bacteria secrete their toxins and these toxins interact with specific receptors located on the host cell surface. In most cases, PFT are activated by host proteases after receptor binding inducing the formation of an oligomeric structure that is insertion competent. Finally, membrane insertion is triggered, in most cases, by a decrease in pH that induces a molten globule state of the protein. Id.
The development of transgenic crops that produce Bt Cry proteins has allowed the substitution of chemical insecticides by environmentally friendly alternatives. In transgenic plants the Cry toxin is produced continuously, protecting the toxin from degradation and making it reachable to chewing and boring insects. Cry protein production in plants has been improved by engineering cry genes with a plant biased codon usage, by removal of putative splicing signal sequences and deletion of the carboxy-terminal region of the protoxin. See, Schuler T H, et al., “Insect-resistant transgenic plants,” Trends Biotechnol. 1998; 16:168-175. The use of insect resistant crops has diminished considerably the use of chemical pesticides in areas where these transgenic crops are planted. See, Qaim M, Zilberman D, “Yield effects of genetically modified crops in developing countries,” Science. 2003 Feb. 7; 299(5608):900-2.
Known Cry proteins include: δ-endotoxins including but not limited to: the Cry1, Cry2, Cry3, Cry4, Cry5, Cry6, Cry7, Cry8, Cry9, Cry10, Cry11, Cry12, Cry13, Cry14, Cry15, Cry16, Cry17, Cry18, Cry19, Cry20, Cry21, Cry22, Cry23, Cry24, Cry25, Cry26, Cry27, Cry 28, Cry 29, Cry 30, Cry31, Cry32, Cry33, Cry34, Cry35, Cry36, Cry37, Cry38, Cry39, Cry40, Cry41, Cry42, Cry43, Cry44, Cry45, Cry 46, Cry47, Cry49, Cry 51, Cry52, Cry 53, Cry 54, Cry55, Cry56, Cry57, Cry58, Cry59. Cry60, Cry61, Cry62, Cry63, Cry64, Cry65, Cry66, Cry67, Cry68, Cry69, Cry70 and Cry71 classes of δ-endotoxin genes and the B. thuringiensis cytolytic cyt1 and cyt2 genes.
Members of these classes of B. thuringiensis insecticidal proteins include, but are not limited to: Cry1Aa1 (Accession #AAA22353); Cry1Aa2 (Accession #Accession #AAA22552); Cry1Aa3 (Accession #BAA00257); Cry1Aa4 (Accession #CAA31886); Cry1Aa5 (Accession #BAA04468); Cry1Aa6 (Accession #AAA86265); Cry1Aa7 (Accession #AAD46139); Cry1Aa8 (Accession #126149); Cry1Aa9 (Accession #BAA77213); Cry1Aa10 (Accession #AAD55382); Cry1Aa11 (Accession #CAA70856); Cry1Aa12 (Accession #AAP80146); Cry1Aa13 (Accession #AAM44305); Cry1Aa14 (Accession #AAP40639); Cry1Aa15 (Accession #AAY66993); Cry1Aa16 (Accession #HQ439776); Cry1Aa17 (Accession #HQ439788); Cry1Aa18 (Accession #HQ439790); Cry1Aa19 (Accession #HQ685121); Cry1Aa20 (Accession #JF340156); Cry1Aa21 (Accession #JN651496); Cry1Aa22 (Accession #KC158223); Cry1Ab1 (Accession #AAA22330); Cry1Ab2 (Accession #AAA22613); Cry1Ab3 (Accession #AAA22561); Cry1Ab4 (Accession #BAA00071); Cry1Ab5 (Accession #CAA28405); Cry1Ab6 (Accession #AAA22420); Cry1Ab7 (Accession #CAA31620); Cry1Ab8 (Accession #AAA22551); Cry1Ab9 (Accession #CAA38701); Cry1Ab10 (Accession #A29125); Cry1Ab11 (Accession #112419); Cry1Ab12 (Accession #AAC64003); Cry1Ab13 (Accession #AAN76494); Cry1Ab14 (Accession #AAG16877); Cry1Ab15 (Accession #AA013302); Cry1Ab16 (Accession #AAK55546); Cry1Ab17 (Accession #AAT46415); Cry1Ab18 (Accession #AAQ88259); Cry1Ab19 (Accession #AAW31761); Cry1Ab20 (Accession #ABB72460); Cry1Ab21 (Accession #ABS18384); Cry1Ab22 (Accession #ABW87320); Cry1Ab23 (Accession #HQ439777); Cry1Ab24 (Accession #HQ439778); Cry1Ab25 (Accession #HQ685122); Cry1Ab26 (Accession #HQ847729); Cry1Ab27 (Accession #JN135249); Cry1Ab28 (Accession #JN135250); Cry1Ab29 (Accession #JN135251); Cry1Ab30 (Accession #JN135252); Cry1Ab31 (Accession #JN135253); Cry1Ab32 (Accession #JN135254); Cry1Ab33 (Accession #AAS93798); Cry1Ab34 (Accession #KC156668); Cry1Ab-like (Accession #AAK14336); Cry1Ab-like (Accession #AAK14337); Cry1Ab-like (Accession #AAK14338); Cry1Ab-like (Accession #ABG88858); Cry1Ac1 (Accession #AAA22331); Cry1Ac2 (Accession #AAA22338); Cry1Ac3 (Accession #CAA38098); Cry1Ac4 (Accession #AAA73077); Cry1Ac5 (Accession #AAA22339); Cry1Ac6 (Accession #AAA86266); Cry1Ac7 (Accession #AAB46989); Cry1Ac8 (Accession #AAC44841); Cry1Ac9 (Accession #AAB49768); Cry1Ac10 (Accession #CAA05505); Cry1Ac11 (Accession #CAA10270); Cry1Ac12 (Accession #112418); Cry1Ac13 (Accession # AAD38701); Cry1Ac14 (Accession #AAQ06607); Cry1Ac15 (Accession #AAN07788); Cry1Ac16 (Accession #AAU87037); Cry1Ac17 (Accession #AAX18704); Cry1Ac18 (Accession #AAY88347); Cry1Ac19 (Accession #ABD37053); Cry1Ac20 (Accession #ABB89046); Cry1Ac21 (Accession #AAY66992); Cry1Ac22 (Accession #ABZ01836); Cry1Ac23 (Accession #CAQ30431); Cry1Ac24 (Accession #ABL01535); Cry1Ac25 (Accession #FJ513324); Cry1Ac26 (Accession #FJ617446); Cry1Ac27 (Accession #FJ617447); Cry1Ac28 (Accession #ACM90319); Cry1Ac29 (Accession #DQ438941); Cry1Ac30 (Accession #GQ227507); Cry1Ac31 (Accession #GU446674); Cry1Ac32 (Accession #HM061081); Cry1Ac33 (Accession #GQ866913); Cry1Ac34 (Accession #HQ230364); Cry1Ac35 (Accession #JF340157); Cry1Ac36 (Accession #JN387137); Cry1Ac37 (Accession #JQ317685); Cry1Ad1 (Accession #AAA22340); Cry1Ad2 (Accession #CAA01880); Cry1Ae1 (Accession #AAA22410); Cry1Af1 (Accession #AAB82749); Cry1Ag1 (Accession #AAD46137); Cry1Ah1 (Accession #AAQ14326); Cry1Ah2 (Accession #ABB76664); Cry1Ah3 (Accession #HQ439779); Cry1Ai1 (Accession #AA039719); Cry1Ai2 (Accession #HQ439780); Cry1A-like (Accession #AAK14339); Cry1Ba1 (Accession #CAA29898); Cry1Ba2 (Accession #CAA65003); Cry1Ba3 (Accession #AAK63251); Cry1Ba4 (Accession #AAK51084); Cry1Ba5 (Accession #AB020894); Cry1Ba6 (Accession #ABL60921); Cry1Ba7 (Accession #HQ439781); Cry1Bb1 (Accession #AAA22344); Cry1Bb2 (Accession #HQ439782); Cry1Bc1 (Accession #CAA86568); Cry1Bd1 (Accession #AAD10292); Cry1Bd2 (Accession #AAM93496); Cry1Be1 (Accession #AAC32850); Cry1Be2 (Accession #AAQ52387); Cry1Be3 (Accession #ACV96720); Cry1Be4 (Accession #HM070026); Cry1Bf1 (Accession #CAC50778); Cry1Bf2 (Accession #AAQ52380); Cry1Bg1 (Accession #AA039720); Cry1Bh1 (Accession #HQ589331); Cry1Bi1 (Accession #KC156700); Cry1Ca1 (Accession #CAA30396); Cry1Ca2 (Accession #CAA31951); Cry1Ca3 (Accession #AAA22343); Cry1Ca4 (Accession #CAA01886); Cry1Ca5 (Accession #CAA65457); Cry1Ca6 [1] (Accession #AAF37224); Cry1Ca7 (Accession #AAG50438); Cry1Ca8 (Accession #AAM00264); Cry1Ca9 (Accession #AAL79362); Cry1Ca10 (Accession #AAN16462); Cry1Ca11(Accession #AAX53094); Cry1Ca12 (Accession #HM070027); Cry1Ca13 (Accession #HQ412621); Cry1Ca14 (Accession #JN651493); Cry1Cb1 (Accession #M97880); Cry1Cb2 (Accession #AAG35409); Cry1Cb3 (Accession #ACD50894); Cry1Cb-like (Accession #AAX63901); Cry1Da1 (Accession #CAA38099); Cry1Da2 (Accession #176415); Cry1Da3 (Accession #HQ439784); Cry1db1 (Accession #CAA80234); Cry1db2 (Accession #AAK48937); Cry1 Dc1 (Accession #ABK35074); Cry1Ea1 (Accession #CAA37933); Cry1Ea2 (Accession # CAA39609); Cry1Ea3 (Accession #AAA22345); Cry1Ea4 (Accession #AAD04732); Cry1Ea5 (Accession #A15535); Cry1Ea6 (Accession #AAL50330); Cry1Ea7 (Accession #AAW72936); Cry1Ea8 (Accession #ABX11258); Cry1Ea9 (Accession #HQ439785); Cry1Ea10 (Accession #ADR00398); Cry1Ea11 (Accession #JQ652456); Cry1Eb1 (Accession #AAA22346); Cry1Fa1 (Accession #AAA22348); Cry1Fa2 (Accession #AAA22347); Cry1Fa3 (Accession #HM070028); Cry1Fa4 (Accession #HM439638); Cry1 Fb1 (Accession #CAA80235); Cry1Fb2 (Accession #BAA25298); Cry1Fb3 (Accession #AAF21767); Cry1Fb4 (Accession #AAC10641); Cry1Fb5 (Accession #AA013295); Cry1Fb6 (Accession #ACD50892); Cry1Fb7 (Accession #ACD50893); Cry1Ga1 (Accession #CAA80233); Cry1Ga2 (Accession #CAA70506); Cry1Gb1 (Accession #AAD10291); Cry1Gb2 (Accession #AA013756); Cry1Gc1 (Accession #AAQ52381); Cry1Ha1 (Accession #CAA80236); Cry1Hb1 (Accession #AAA79694); Cry1Hb2 (Accession #HQ439786); Cry1H-like (Accession #AAF01213); Cry1Ia1 (Accession #CAA44633); Cry1Ia2 (Accession #AAA22354); Cry1Ia3 (Accession #AAC36999); Cry1Ia4 (Accession #AAB00958); Cry1Ia5 (Accession #CAA70124); Cry1Ia6 (Accession #AAC26910); Cry1Ia7 (Accession #AAM73516); Cry1Ia8 (Accession #AAK66742); Cry1Ia9 (Accession #AAQ08616); Cry1Ia10 (Accession #AAP86782); Cry1Ia11 (Accession #CAC85964); Cry1Ia12 (Accession #AAV53390); Cry1Ia13 (Accession #ABF83202); Cry1Ia14 (Accession #ACG63871); Cry1Ia15 (Accession #FJ617445); Cry1Ia16 (Accession #FJ617448); Cry1Ia17 (Accession #GU989199); Cry1Ia18 (Accession #ADK23801); Cry1Ia19 (Accession #HQ439787); Cry1Ia20 (Accession #JQ228426); Cry1Ia21 (Accession #JQ228424); Cry1Ia22 (Accession #JQ228427); Cry1Ia23 (Accession #JQ228428); Cry1Ia24 (Accession #JQ228429); Cry1Ia25 (Accession #JQ228430); Cry1Ia26 (Accession #JQ228431); Cry1Ia27 (Accession #JQ228432); Cry1Ia28 (Accession #JQ228433); Cry1Ia29 (Accession #JQ228434); Cry1Ia30 (Accession #JQ317686); Cry1Ia31 (Accession #JX944038); Cry1Ia32 (Accession #JX944039); Cry1Ia33 (Accession #JX944040); Cry1Ib1 (Accession #AAA82114); Cry1Ib2 (Accession #ABW88019); Cry1Ib3 (Accession #ACD75515); Cry1Ib4 (Accession #HM051227); Cry1Ib5 (Accession #HM070028); Cry1Ib6 (Accession #ADK38579); Cry1Ib7 (Accession #JN571740); Cry1Ib8 (Accession #JN675714); Cry1Ib9 (Accession #JN675715); Cry1Ib10 (Accession #JN675716); Cry1Ib11 (Accession #JQ228423); Cry1Ic1 (Accession #AAC62933); Cry1Ic2 (Accession #AAE71691); Cry1Id1 (Accession #AAD44366); Cry1Id2 (Accession #JQ228422); Cry1Ie1 (Accession #AAG43526); Cry1Ie2 (Accession #HM439636); Cry1Ie3 (Accession #KC156647); Cry1Ie4 (Accession #KC156681); Cryllf1 (Accession #AAQ52382); Cry1Ig1 (Accession #KC156701); Cry1I-like (Accession #AAC31094); Cry1I-like (Accession #ABG88859); Cry1Ja1 (Accession #AAA22341); Cry1Ja2 (Accession #HM070030); Cry1Ja3 (Accession #JQ228425); Cry1Jb1 (Accession #AAA98959); Cry1Jc1 (Accession #AAC31092); Cry1Jc2 (Accession #AAQ52372); Cry1Jd1 (Accession #CAC50779); Cry1Ka1 (Accession #AAB00376); Cry1Ka2 (Accession #HQ439783); Cry1La1 (Accession #AAS60191); Cry1La2 (Accession #HM070031); Cry1Ma1 (Accession #FJ884067); Cry1Ma2 (Accession #KC156659); Cry1Na1 (Accession #KC156648); Cry1Nb1 (Accession #KC156678); Cry1-like (Accession #AAC31091); Cry2Aa1 (Accession #AAA22335); Cry2Aa2 (Accession #AAA83516); Cry2Aa3 (Accession #D86064); Cry2Aa4 (Accession #AAC04867); Cry2Aa5 (Accession #CAA10671); Cry2Aa6 (Accession #CAA10672); Cry2Aa7 (Accession #CAA10670); Cry2Aa8 (Accession #AA013734); Cry2Aa9 (Accession #AA013750); Cry2Aa10 (Accession #AAQ04263); Cry2Aa11 (Accession #AAQ52384); Cry2Aa12 (Accession #AB183671); Cry2Aa13 (Accession #ABL01536); Cry2Aa14 (Accession #ACF04939); Cry2Aa15 (Accession #JN426947); Cry2Ab1 (Accession #AAA22342); Cry2Ab2 (Accession #CAA39075); Cry2Ab3 (Accession #AAG36762); Cry2Ab4 (Accession #AA013296); Cry2Ab5 (Accession #AAQ04609); Cry2Ab6 (Accession #AAP59457); Cry2Ab7 (Accession #AAZ66347); Cry2Ab8 (Accession #ABC95996); Cry2Ab9 (Accession #ABC74968); Cry2Ab10 (Accession #EF157306); Cry2Ab11 (Accession #CAM84575); Cry2Ab12 (Accession #ABM21764); Cry2Ab13 (Accession #ACG76120); Cry2Ab14 (Accession #ACG76121); Cry2Ab15 (Accession #HM037126); Cry2Ab16 (Accession #GQ866914); Cry2Ab1 7 (Accession #HQ439789); Cry2Ab18 (Accession #JN135255); Cry2Ab19 (Accession #JN135256); Cry2Ab20 (Accession #JN135257); Cry2Ab21 (Accession #JN135258); Cry2Ab22 (Accession #JN135259); Cry2Ab23 (Accession #JN135260); Cry2Ab24 (Accession #JN135261); Cry2Ab25 (Accession #JN415485); Cry2Ab26 (Accession #JN426946); Cry2Ab27 (Accession #JN415764); Cry2Ab28 (Accession #JN651494); Cry2Ac1 (Accession #CAA40536); Cry2Ac2 (Accession #AAG35410); Cry2Ac3 (Accession #AAQ52385); Cry2Ac4 (Accession #ABC95997); Cry2Ac5 (Accession #ABC74969); Cry2Ac6 (Accession #ABC74793); Cry2Ac7 (Accession #CAL18690); Cry2Ac8 (Accession #CAM09325); Cry2Ac9 (Accession #CAM09326); Cry2Ac10 (Accession #ABN15104); Cry2Ac11 (Accession #CAM83895); Cry2Ac12 (Accession #CAM83896); Cry2Ad1 (Accession #AAF09583); Cry2Ad2 (Accession #ABC86927); Cry2Ad3 (Accession #CAK29504); Cry2Ad4 (Accession #CAM32331); Cry2Ad5 (Accession #CA078739); Cry2Ae1 (Accession #AAQ52362); Cry2Af1 (Accession #AB030519); Cry2Af2 (Accession #GQ866915); Cry2Ag1 (Accession #ACH91610); Cry2Ah1 (Accession #EU939453); Cry2Ah2 (Accession #ACL80665); Cry2Ah3 (Accession #GU073380); Cry2Ah4 (Accession #KC156702); Cry2Ai1 (Accession #FJ788388); Cry2Aj (Accession #); Cry2Ak1 (Accession #KC156660); Cry2Ba1 (Accession #KC156658); Cry3Aa1 (Accession #AAA22336); Cry3Aa2 (Accession #AAA22541); Cry3Aa3 (Accession #CAA68482); Cry3Aa4 (Accession #AAA22542); Cry3Aa5 (Accession #AAA50255); Cry3Aa6 (Accession #AAC43266); Cry3Aa7 (Accession #CAB41411); Cry3Aa8 (Accession #AAS79487); Cry3Aa9 (Accession #AAW05659); Cry3Aa10 (Accession #AAU29411); Cry3Aa11 (Accession #AAW82872); Cry3Aa12 (Accession #ABY49136); Cry3Ba1 (Accession #CAA34983); Cry3Ba2 (Accession #CAA00645); Cry3Ba3 (Accession #JQ397327); Cry3Bb1 (Accession #AAA22334); Cry3Bb2 (Accession #AAA74198); Cry3Bb3 (Accession #115475); Cry3Ca1 (Accession #CAA42469); Cry4Aa1 (Accession #CAA68485); Cry4Aa2 (Accession #BAAOOl 79); Cry4Aa3 (Accession #CAD30148); Cry4Aa4 (Accession #AFB18317); Cry4A-like (Accession #AAY96321); Cry4Ba1 (Accession #CAA30312); Cry4Ba2 (Accession #CAA30114); Cry4Ba3 (Accession #AAA22337); Cry4Ba4 (Accession #BAAOOl 78); Cry4Ba5 (Accession #CAD30095); Cry4Ba-like (Accession #ABC47686); Cry4Ca1 (Accession #EU646202); Cry4Cb1 (Accession #FJ403208); Cry4Cb2 (Accession #FJ597622); Cry4Cc1 (Accession #FJ403207); Cry5Aa1 (Accession #AAA67694); Cry5Ab1 (Accession #AAA67693); Cry5Ac1 (Accession #I34543); Cry5Ad1 (Accession #ABQ82087); Cry5Ba1 (Accession #AAA68598); Cry5Ba2 (Accession #ABW88931); Cry5Ba3 (Accession #AFJ04417); Cry5Ca1 (Accession #HM461869); Cry5Ca2 (Accession #ZP_04123426); Cry5Da1 (Accession #HM461870); Cry5Da2 (Accession #ZP_04123980); Cry5Ea1 (Accession #HM485580); Cry5Ea2 (Accession #ZP_04124038); Cry6Aa1 (Accession #AAA22357); Cry6Aa2 (Accession #AAM46849); Cry6Aa3 (Accession #ABH03377); Cry6Ba1 (Accession #AAA22358); Cry7 Aa1 (Accession #AAA22351); Cry7Ab1 (Accession #AAA21120); Cry7Ab2 (Accession #AAA21121); Cry7Ab3 (Accession #ABX24522); Cry7 Ab4 (Accession #EU380678); Cry7 Ab5 (Accession #ABX79555); Cry7 Ab6 (Accession #ACI44005); Cry7 Ab7 (Accession #ADB89216); Cry7 Ab8 (Accession #GU145299); Cry7Ab9 (Accession #ADD92572); Cry7Ba1 (Accession #ABB70817); Cry7Bb1 (Accession #KC156653); Cry7Ca1 (Accession #ABR67863); Cry7Cb1 (Accession #KC156698); Cry7Da1 (Accession #ACQ99547); Cry7Da2 (Accession #HM572236); Cry7Da3 (Accession #KC156679); Cry7Ea1 (Accession #HM035086); Cry7Ea2 (Accession #HM132124); Cry7Ea3 (Accession #EEM19403); Cry7Fa1 (Accession #HM035088); Cry7Fa2 (Accession #EEM19090); Cry7Fb1 (Accession #HM572235); Cry7Fb2 (Accession #KC156682); Cry7Ga1 (Accession #HM572237); Cry7Ga2 (Accession #KC156669); Cry7Gb1 (Accession #KC156650); Cry7Gc1 (Accession #KC156654); Cry7Gd1 (Accession #KC156697); Cry7Ha1 (Accession #KC156651); Cry7Ia1 (Accession #KC156665); Cry7Ja1 (Accession #KC156671); Cry7Ka1 (Accession #KC156680); Cry7Kb1 (Accession #BAM99306); Cry7La1 (Accession #BAM99307); Cry8Aa1 (Accession #AAA21117); Cry8Ab1 (Accession #EU044830); Cry8Ac1 (Accession #KC156662); Cry8Ad1 (Accession #KC156684); Cry8Ba1 (Accession #AAA21118); Cry8Bb1 (Accession #CAD57542); Cry8Bc1 (Accession #CAD57543); Cry8Ca1 (Accession #AAA21119); Cry8Ca2 (Accession #AAR98783); Cry8Ca3 (Accession #EU625349); Cry8Ca4 (Accession #ADB54826); Cry8Da1 (Accession #BAC07226); Cry8Da2 (Accession #BD133574); Cry8Da3 (Accession #BD133575); Cry8db1 (Accession #BAF93483); Cry8Ea1 (Accession #AAQ73470); Cry8Ea2 (Accession #EU047597); Cry8Ea3 (Accession #KC855216); Cry8Fa1 (Accession #AAT48690); Cry8Fa2 (Accession #HQ1 74208); Cry8Fa3 (Accession #AFH78109); Cry8Ga1 (Accession #AAT46073); Cry8Ga2 (Accession #ABC42043); Cry8Ga3 (Accession #FJ198072); Cry8Ha1 (Accession #AAW81032); Cry8Ia1 (Accession #EU381044); Cry8Ia2 (Accession #GU073381); Cry8Ia3 (Accession #HM044664); Cry8Ia4 (Accession #KC156674); Cry8Ib1 (Accession #GU325772); Cry8Ib2 (Accession #KC156677); Cry8Ja1 (Accession #EU625348); Cry8Ka1 (Accession #FJ422558); Cry8Ka2 (Accession #ACN87262); Cry8Kb1 (Accession #HM123758); Cry8Kb2 (Accession #KC156675); Cry8La1 (Accession #GU325771); Cry8Ma1 (Accession #HM044665); Cry8Ma2 (Accession #EEM86551); Cry8Ma3 (Accession #HM210574); Cry8Na1 (Accession #HM640939); Cry8Pa1 (Accession #HQ388415); Cry8Qa1 (Accession #HQ441166); Cry8Qa2 (Accession #KC152468); Cry8Ra1 (Accession #AFP87548); Cry8Sa1 (Accession #JQ740599); Cry8Ta1 (Accession #KC156673); Cry8-like (Accession #FJ770571); Cry8-like (Accession #ABS53003); Cry9Aa1 (Accession #CAA41122); Cry9Aa2 (Accession #CAA41425); Cry9Aa3 (Accession #GQ249293); Cry9Aa4 (Accession #GQ249294); Cry9Aa5 (Accession #JX1 74110); Cry9Aa like (Accession #AAQ52376); Cry9Ba1 (Accession #CAA52927); Cry9Ba2 (Accession #GU299522); Cry9Bb1 (Accession #AAV28716); Cry9Ca1 (Accession #CAA85764); Cry9Ca2 (Accession #AAQ52375); Cry9Da1 (Accession #BAA1 9948); Cry9Da2 (Accession #AAB97923); Cry9Da3 (Accession #GQ249293); Cry9Da4 (Accession #GQ249297); Cry9db1 (Accession #AAX78439); Cry9Dc1 (Accession #KCl 56683); Cry9Ea1 (Accession #BAA34908); Cry9Ea2 (Accession #AA012908); Cry9Ea3 (Accession #ABM21765); Cry9Ea4 (Accession #ACE88267); Cry9Ea5 (Accession #ACF04743); Cry9Ea6 (Accession #ACG63872); Cry9Ea7 (Accession #FJ380927); Cry9Ea8 (Accession #GQ249292); Cry9Ea9 (Accession #JN651495); Cry9Eb1 (Accession #CAC50780); Cry9Eb2 (Accession #GQ249298); Cry9Eb3 (Accession #KC156646); Cry9Ec1 (Accession #AAC63366); Cry9Ed1 (Accession #AAX78440); Cry9Ee1 (Accession #GQ249296); Cry9Ee2 (Accession #KC156664); Cry9Fa1 (Accession #KC156692); Cry9Ga1 (Accession #KC156699); Cry9-like (Accession #AAC63366); Cry10Aa1 (Accession #AAA22614); Cry10Aa2 (Accession #E00614); Cry10Aa3 (Accession #CAD30098); Cry10Aa4 (Accession #AFB18318); Cry10A-like (Accession #DQ167578); Cry11Aa1 (Accession #AAA22352); Cry11Aa2 (Accession #AAA22611); Cry11Aa3 (Accession #CAD30081); Cry11Aa4 (Accession #AFB18319); Cry11Aa-like (Accession #DQ166531); Cry11Ba1 (Accession #CAA60504); Cry11Bb1 (Accession #AAC97162); Cry11Bb2 (Accession #HM068615); Cry12Aa1 (Accession #AAA22355); Cry13Aa1 (Accession #AAA22356); Cry14Aa1 (Accession #AAA21516); Cry14Ab1 (Accession #KC156652); Cry15Aa1 (Accession #AAA22333); Cry16Aa1 (Accession #CAA63860); Cry17Aa1 (Accession #CAA67841); Cry18Aa1 (Accession #CAA67506); Cry18Ba1 (Accession #AAF89667); Cry18Ca1 (Accession #AAF89668); Cry19Aa1 (Accession #CAA68875); Cry19Ba1 (Accession #BAA32397); Cry19Ca1 (Accession #AFM37572); Cry20Aa1 (Accession #AAB93476); Cry20Ba1 (Accession #ACS93601); Cry20Ba2 (Accession #KC156694); Cry20-like (Accession #GQ144333); Cry21Aa1 (Accession #I32932); Cry21Aa2 (Accession #I66477); Cry21Ba1 (Accession #BAC06484); Cry21Ca1 (Accession #JF521577); Cry21Ca2 (Accession #KC156687); Cry21Da1 (Accession #JF521578); Cry22Aa1 (Accession #I34547); Cry22Aa2 (Accession #CAD43579); Cry22Aa3 (Accession #ACD93211); Cry22Ab1 (Accession #AAK50456); Cry22Ab2 (Accession #CAD43577); Cry22Ba1 (Accession #CAD43578); Cry22Bb1 (Accession #KC156672); Cry23Aa1 (Accession #AAF76375); Cry24Aa1 (Accession #AAC61891); Cry24Ba1 (Accession #BAD32657); Cry24Ca1 (Accession #CAJ43600); Cry25Aa1 (Accession #AAC61892); Cry26Aa1 (Accession #AAD25075); Cry27Aa1 (Accession #BAA82796); Cry28Aa1 (Accession #AAD24189); Cry28Aa2 (Accession #AAG00235); Cry29Aa1 (Accession #CAC80985); Cry30Aa1 (Accession #CAC80986); Cry30Ba1 (Accession #BAD00052); Cry30Ca1 (Accession #BAD67157); Cry30Ca2 (Accession #ACU24781); Cry30Da1 (Accession #EF095955); Cry30db1 (Accession #BAE80088); Cry30Ea1 (Accession #ACC95445); Cry30Ea2 (Accession #FJ499389); Cry30Fa1 (Accession #ACI22625); Cry30Ga1 (Accession #ACG60020); Cry30Ga2 (Accession #HQ638217); Cry31Aa1 (Accession #BABll 757); Cry31Aa2 (Accession #AAL87458); Cry31Aa3 (Accession #BAE79808); Cry31Aa4 (Accession #BAF32571); Cry31Aa5 (Accession #BAF32572); Cry31Aa6 (Accession #BA144026); Cry31Ab1 (Accession #BAE79809); Cry31Ab2 (Accession #BAF32570); Cry31Ac1 (Accession #BAF34368); Cry31Ac2 (Accession #AB731600); Cry31Ad1 (Accession #BA144022); Cry32Aa1 (Accession #AAG36711); Cry32Aa2 (Accession #GU063849); Cry32Ab1 (Accession #GU063850); Cry32Ba1 (Accession #BAB78601); Cry32Ca1 (Accession #BAB78602); Cry32Cb1 (Accession #KC156708); Cry32Da1 (Accession #BAB78603); Cry32Ea1 (Accession #GU324274); Cry32Ea2 (Accession #KC156686); Cry32Eb1 (Accession #KC156663); Cry32Fa1 (Accession #KC156656); Cry32Ga1 (Accession #KC156657); Cry32Ha1 (Accession #KC156661); Cry32Hb1 (Accession #KC156666); Cry32Ia1 (Accession #KCl 56667); Cry32Ja1 (Accession #KCl 56685); Cry32Ka1 (Accession #KC156688); Cry32La1 (Accession #KC156689); Cry32Ma1 (Accession #KC156690); Cry32Mb1 (Accession #KC156704); Cry32Na1 (Accession #KC156691); Cry320a1 (Accession #KC156703); Cry32Pa1 (Accession #KC156705); Cry32Qa1 (Accession #KC156706); Cry32Ra1 (Accession #KC156707); Cry32Sa1 (Accession #KC156709); Cry32Ta1 (Accession #KC156710); Cry32Ua1 (Accession #KC156655); Cry33Aa1 (Accession #AAL26871); Cry34Aa1 (Accession #AAG50341); Cry34Aa2 (Accession #AAK64560); Cry34Aa3 (Accession #AAT29032); Cry34Aa4 (Accession #AAT29030); Cry34Ab1 (Accession #AAG41671); Cry34Ac1 (Accession #AAG50118); Cry34Ac2 (Accession #AAK64562); Cry34Ac3 (Accession #AAT29029); Cry34Ba1 (Accession #AAK64565); Cry34Ba2 (Accession #AAT29033); Cry34Ba3 (Accession #AAT29031); Cry35Aa1 (Accession #AAG50342); Cry35Aa2 (Accession #AAK64561); Cry35Aa3 (Accession #AAT29028); Cry35Aa4 (Accession #AAT29025); Cry35Ab1 (Accession #AAG41672); Cry35Ab2 (Accession #AAK64563); Cry35Ab3 (Accession #AY536891); Cry35Ac1 (Accession #AAG50117); Cry35Ba1 (Accession #AAK64566); Cry35Ba2 (Accession #AAT29027); Cry35Ba3 (Accession #AAT29026); Cry36Aa1 (Accession #AAK64558); Cry37 Aa1 (Accession #AAF76376); Cry38Aa1 (Accession #AAK64559); Cry39Aa1 (Accession #BAB72016); Cry40Aa1 (Accession #BAB72018); Cry40Ba1 (Accession #BAC77648); Cry40Ca1 (Accession #EU381045); Cry40Da1 (Accession #ACF15199); Cry41Aa1 (Accession #BAD35157); Cry41Ab1 (Accession #BAD35163); Cry41Ba1 (Accession #HM461871); Cry41Ba2 (Accession #ZP_04099652); Cry42Aa1 (Accession #BAD35166); Cry43Aa1 (Accession #BAD15301); Cry43Aa2 (Accession #BAD95474); Cry43Ba1 (Accession #BAD15303); Cry43Ca1 (Accession #KC156676); Cry43Cb1 (Accession #KC156695); Cry43Cc1 (Accession #KC156696); Cry43-like (Accession #BAD15305); Cry44Aa (Accession #BAD08532); Cry45Aa (Accession #BAD22577); Cry46Aa (Accession #BAC79010); Cry46Aa2 (Accession #BAG68906); Cry46Ab (Accession #BAD35170); Cry47 Aa (Accession #AAY24695); Cry48Aa (Accession #CAJ18351); Cry48Aa2 (Accession #CAJ86545); Cry48Aa3 (Accession #CAJ86546); Cry48Ab (Accession #CAJ86548); Cry48Ab2 (Accession #CAJ86549); Cry49Aa (Accession #CAH56541); Cry49Aa2 (Accession #CAJ86541); Cry49Aa3 (Accession #CAJ86543); Cry49Aa4 (Accession #CAJ86544); Cry49Ab1 (Accession #CAJ86542); Cry50Aa1 (Accession #BAE86999); Cry50Ba1 (Accession #GU446675); Cry50Ba2 (Accession #GU446676); Cry51Aa1 (Accession #AB114444); Cry51Aa2 (Accession #GU570697); Cry52Aa1 (Accession #EF613489); Cry52Ba1 (Accession #FJ361760); Cry53Aa1 (Accession #EF633476); Cry53Ab1 (Accession #FJ361759); Cry54Aa1 (Accession #ACA52194); Cry54Aa2 (Accession #GQ140349); Cry54Ba1 (Accession #GU446677); Cry55Aa1 (Accession #ABW88932); Cry54Ab1 (Accession #JQ916908); Cry55Aa2 (Accession #AAE33526); Cry56Aa1 (Accession #ACU57499); Cry56Aa2 (Accession #GQ483512); Cry56Aa3 (Accession #JX025567); Cry57Aa1 (Accession #ANC87261); Cry58Aa1 (Accession #ANC87260); Cry59Ba1 (Accession #JN790647); Cry59Aa1 (Accession #ACR43758); Cry60Aa1 (Accession #ACU24782); Cry60Aa2 (Accession #EA057254); Cry60Aa3 (Accession #EEM99278); Cry60Ba1 (Accession #GU810818); Cry60Ba2 (Accession #EA057253); Cry60Ba3 (Accession #EEM99279); Cry61Aa1 (Accession #HM035087); Cry61Aa2 (Accession #HM132125); Cry61Aa3 (Accession #EEM19308); Cry62Aa1 (Accession #HM054509); Cry63Aa1 (Accession #BA144028); Cry64Aa1 (Accession #BAJ05397); Cry65Aa1 (Accession #HM461868); Cry65Aa2 (Accession #ZP_04123838); Cry66Aa1 (Accession #HM485581); Cry66Aa2 (Accession #ZP_04099945); Cry67Aa1 (Acces-sion #HM485582); Cry67Aa2 (Accession #ZP_04148882); Cry68Aa1 (Accession #HQ113114); Cry69Aa1 (Accession #HQ401006); Cry69Aa2 (Accession #JQ821388); Cry69Ab1 (Accession #JN209957); Cry70Aa1 (Accession #JN646781); Cry70Ba1 (Accession #AD051070); Cry70Bb1 (Accession #EEL67276); Cry71Aa1 (Accession #JX025568); Cry72Aa1 (Accession #JX025569); Cyt1Aa (GenBank Accession Number X03182); Cyt1Ab (GenBank Accession Number X98793); Cyt1B (GenBank Accession Number U37196); Cyt2A (GenBank Accession Number Z14147); and Cyt2B (GenBank Accession Number U52043).
Examples of δ-endotoxins also include but are not limited to Cry1A proteins of U.S. Pat. Nos. 5,880,275, 7,858,849 8,530,411, 8,575,433, and 8,686,233; a DIG-3 or DIG-11 toxin (N-terminal deletion of a-helix 1 and/or a-helix 2 variants of cry proteins such as Cry1A, Cry3A) of U.S. Pat. Nos. 8,304,604, 8,304,605 and 8,476,226; Cry1B of U.S. patent application Ser. No. 10/525,318; Cry1C of U.S. Pat. No. 6,033,874; Cry1F of U.S. Pat. Nos. 5,188,960 and 6,218,188; Cry1A/F chimeras of U.S. Pat. Nos. 7,070,982; 6,962,705 and 6,713,063); a Cry2 protein such as Cry2Ab protein of U.S. Pat. No. 7,064,249); a Cry3A protein including but not limited to an engineered hybrid insecticidal protein (eHIP) created by fusing unique combinations of variable regions and conserved blocks of at least two different Cry proteins (US Patent Application Publication Number 2010/0017914); a Cry4 protein; a Cry5 protein; a Cry6 protein; Cry8 proteins of U.S. Pat. Nos. 7,329,736, 7,449,552, 7,803,943, 7,476,781, 7,105,332, 7,378,499 and 7,462,760; a Cry9 protein such as such as members of the Cry9A, Cry9B, Cry9C, Cry9D, Cry9E and Cry9F families, including but not limited to the Cry9D protein of U.S. Pat. No. 8,802,933 and the Cry9B protein of U.S. Pat. No. 8,802,934; a Cry15 protein of Naimov, et al., (2008), “Applied and Environmental Microbiology,” 74:7145-7151; a Cry22, a Cry34Ab1 protein of U.S. Pat. Nos. 6,127,180, 6,624,145 and 6,340,593; a CryET33 and cryET34 protein of U.S. Pat. Nos. 6,248,535, 6,326,351, 6,399,330, 6,949,626, 7,385,107 and 7,504,229; a CryET33 and CryET34 homologs of US Patent Publication Number 2006/0191034, 2012/0278954, and PCT Publication Number WO 2012/139004; a Cry35Ab1 protein of U.S. Pat. Nos. 6,083,499, 6,548,291 and 6,340,593; a Cry46 protein, a Cry 51 protein, a Cry binary toxin; a TIC901 or related toxin; TIC807 of US Patent Application Publication Number 2008/0295207; ET29, ET37, TIC809, TIC810, TIC812, TIC127, TIC128 of PCT US 2006/033867; TIC853 toxins of U.S. Pat. No. 8,513,494, AXMI-027, AXMI-036, and AXMI-038 of U.S. Pat. No. 8,236,757; AXMI-031, AXMI-039, AXMI-040, AXMI-049 of U.S. Pat. No. 7,923,602; AXMI-018, AXMI-020 and AXMI-021 of WO 2006/083891; AXMI-010 of WO 2005/038032; AXMI-003 of WO 2005/021585; AXMI-008 of US Patent Application Publication Number 2004/0250311; AXMI-006 of US Patent Application Publication Number 2004/0216186; AXMI-007 of US Patent Applica-tion Publication Number 2004/0210965; AXMI-009 of US Patent Application Number 2004/0210964; AXMI-014 of US Patent Application Publication Number 2004/0197917; AXMI-004 of US Patent Application Publication Number 2004/0197916; AXMI-028 and AXMI-029 of WO 2006/119457; AXMI-007, AXMI-008, AXMI-0080rf2, AXMI-009, AXMI-014 and AXMI-004 of WO 2004/074462; AXMI-150 of U.S. Pat. No. 8,084,416; AXMI-205 of US Patent Application Publication Number 2011/0023184; AXMI-011, AXMI-012, AXMI-013, AXMI-015, AXMI-019, AXMI-044, AXMI-037, AXMI-043, AXMI-033, AXMI-034, AXMI-022, AXMI-023, AXMI-041, AXMI-063 and AXMI-064 of US Patent Application Publication Number 2011/0263488; AXMI-R1 and related proteins of US Patent Application Publication Number 2010/0197592; AXMI221Z, AXMI222z, AXMI223z, AXMI224z and AXMI225z of WO 2011/103248; AXMI218, AXMI219, AXMI220, AXMI226, AXMI227, AXMI228, AXMI229, AXMI230 and AXMI231 of WO 2011/103247 and U.S. Pat. No. 8,759,619; AXMI-115, AXMI-113, AXMI-005, AXMI-163 and AXMI-184 of U.S. Pat. No. 8,334,431; AXMI-001, AXMI-002, AXMI-030, AXMI-035 and AXMI-045 of US Patent Application Publication Number 2010/0298211; AXMI-066 and AXMI-076 of US Patent Application Publication Number 2009/0144852; AXMI128, AXMI130, AXMI131, AXMI133, AXMI140, AXMI141, AXMI142, AXMI143, AXMI144, AXMI146, AXMI148, AXMI149, AXMI152, AXMI153, AXMI154, AXMI155, AXMI156, AXMI157, AXMI158, AXMI162, AXMI165, AXMI166, AXMI167, AXMI168, AXMI169, AXMI170, AXMI171, AXMI172, AXMI173, AXMI174, AXMI175, AXMI176, AXMI177, AXMI178, AXMI179, AXMI180, AXMI181, AXMI182, AXMI185, AXMI186, AXMI187, AXMI188, AXMI189 of U.S. Pat. No. 8,318,900; AXMI079, AXMI080, AXMI081, AXMI082, AXMI091, AXMI092, AXMI096, AXMI097, AXMI098, AXMI099, AXMI100, AXMI101, AXMI102, AXMI103, AXMI104, AXMI107, AXMI108, AXMI109, AXMI110, AXMI111, AXMI112, AXMI114, AXMI116, AXMI117, AXMI118, AXMI119, AXMI120, AXMI121, AXMI122, AXMI123, AXMI124, AXMI1257, AXMI1268, AXMI127, AXMI129, AXMI164, AXMI151, AXMI161, AXMI183, AXMI132, AXMI138, AXMI137 of US Patent Application Publication Number 2010/0005543, AXMI270 of US Patent Application Publication US20140223598, AXMI279 of US Patent Application Publication US20140223599, cry proteins such as Cry1A and Cry3A having modified proteolytic sites of U.S. Pat. No. 8,319,019; a Cry1Ac, Cry2Aa and Cry1Ca toxin protein from Bacillus thuringiensis strain VBTS 2528 of US Patent Application Publication Number 2011/0064710. Other Cry proteins are well known to one skilled in the art. See, N. Crickmore, et al., “Revision of the Nomenclature for the Bacillus thuringiensis Pesticidal Crystal Proteins,” Microbiology and Molecular Biology Reviews,” (1998) Vol 62: 807-813; see also, N. Crickmore, et al., “Bacillus thuringiensis toxin nomenclature” (2016), at www.btnomenclature.info/.
The use of Cry proteins as transgenic plant traits is well known to one skilled in the art and Cry-transgenic plants including but not limited to plants expressing Cry1Ac, Cry1Ac+Cry2Ab, Cry1Ab, Cry1A.105, Cry1F, Cry1Fa2, Cry1F+Cry1Ac, Cry2Ab, Cry3A, mCry3A, Cry3Bb1, Cry34Ab1, Cry35Ab1, Vip3A, mCry3A, Cry9c and CBI-Bt have received regulatory approval. See, Sanahuja et al., “Bacillus thuringiensis: a century of research, development and commercial applications,” (2011) Plant Biotech Journal, April 9(3):283-300 and the CERA (2010) GM Crop Database Center for Environmental Risk Assessment (CERA), ILSI Research Foundation, Washington D.C. at cera-gmc.org/index.php?action=gm_crop_database, which can be accessed on the world-wide web using the “www” prefix). More than one pesticidal proteins well known to one skilled in the art can also be expressed in plants such as Vip3Ab & Cry1Fa (US2012/0317682); Cry1BE & Cry1F (US2012/0311746); Cry1CA & Cry1AB (US2012/0311745); Cry1F & CryCa (US2012/0317681); Cry1DA& Cry1BE (US2012/0331590); Cry1DA & Cry1Fa (US2012/0331589); Cry1AB & Cry1BE (US2012/0324606); Cry1Fa & Cry2Aa and Cry11 & Cry1E (US2012/0324605); Cry34Ab/35Ab and Cry6Aa (US20130167269); Cry34Ab/VCry35Ab & Cry3Aa (US20130167268); Cry1Ab & Cry1F (US20140182018); and Cry3A and Cry1Ab or Vip3Aa (US20130116170). Pesticidal proteins also include insecticidal lipases including lipid acyl hydrolases of U.S. Pat. No. 7,491,869, and cholesterol oxidases such as from Streptomyces (Purcell et al. (1993) Biochem Biophys Res Commun 15:1406-1413).
Pesticidal proteins also include VIP (vegetative insecticidal proteins) toxins. Entomopathogenic bacteria produce insecticidal proteins that accumulate in inclusion bodies or parasporal crystals (such as the aforementioned Cry and Cyt proteins), as well as insecticidal proteins that are secreted into the culture medium. Among the latter are the Vip proteins, which are divided into four families according to their amino acid identity. The Vip1 and Vip2 proteins act as binary toxins and are toxic to some members of the Coleoptera and Hemiptera. The Vip1 component is thought to bind to receptors in the membrane of the insect midgut, and the Vip2 component enters the cell, where it displays its ADP-ribosyltransferase activity against actin, preventing microfilament formation. Vip3 has no sequence similarity to Vip1 or Vip2 and is toxic to a wide variety of members of the Lepidoptera. Its mode of action has been shown to resemble that of the Cry proteins in terms of proteolytic activation, binding to the midgut epithelial membrane, and pore formation, although Vip3A proteins do not share binding sites with Cry proteins. The latter property makes them good candidates to be combined with Cry proteins in transgenic plants (Bacillus thuringiensis-treated crops [Bt crops]) to prevent or delay insect resistance and to broaden the insecticidal spectrum. There are commercially grown varieties of Bt cotton and Bt maize that express the Vip3Aa protein in combination with Cry proteins. For the most recently reported Vip4 family, no target insects have been found yet. See, Chakroun et al., “Bacterial Vegetative Insecticidal Proteins (Vip) from Entomopathogenic Bacteria,” Microbiol Mol Biol Rev. 2016 Mar. 2; 80(2):329-50. VIPs can be found in U.S. Pat. Nos. 5,877,012, 6,107,279 6,137,033, 7,244,820, 7,615,686, and 8,237,020 and the like. Other VIP proteins are well known to one skilled in the art (see, lifesci.sussex.ac.uk/home/Neil_Crickmore/Bt/vip.html, which can be accessed on the world-wide web using the “www” prefix).
Pesticidal proteins also include toxin complex (TC) proteins, obtainable from organisms such as Xenorhabdus, Photorhabdus and Paenibacillus (see, U.S. Pat. Nos. 7,491,698 and 8,084,418). Some TC proteins have “stand alone” insecticidal activity and other TC proteins enhance the activity of the stand-alone toxins produced by the same given organism. The toxicity of a “stand-alone” TC protein (from Photorhabdus, Xenorhabdus or Paenibacillus, for example) can be enhanced by one or more TC protein “potentiators” derived from a source organism of a different genus. There are three main types of TC proteins. As referred to herein, Class A proteins (“Protein A”) are stand-alone toxins. Class B proteins (“Protein B”) and Class C proteins (“Protein C”) enhance the toxicity of Class A proteins. Examples of Class A proteins are TcbA, TcdA, XptAl and XptA2. Examples of Class B proteins are TcaC, TcdB, XptBlXb and XptCl Wi. Examples of Class C proteins are TccC, XptC1Xb and XptBl Wi. Pesticidal proteins also include spider, snake and scorpion venom proteins. Examples of spider venom peptides include, but are not limited to lycotoxin-1 peptides and mutants thereof (U.S. Pat. No. 8,334,366).
Some currently registered PIPs are listed in Table 11. Transgenic plants have also been engineered to express dsRNA directed against insect genes (Baum, J. A. et al. (2007) Control of coleopteran insect pests through RNA interference. Nature Biotechnology 25: 1322-1326; Mao, Y. B. et al. (2007) Silencing a cotton bollworm P450 monooxygenase gene by plant-mediated RNAi impairs larval tolerance of gossypol. Nature Biotechnology 25: 1307-1313). RNA interference can be triggered in the pest by feeding of the pest on the transgenic plant. Pest feeding thus causes injury or death to the pest.
In some embodiments, any one or more of the pesticides set forth herein may be utilized with any one or more of the microbes of the disclosure and can be applied to plants or parts thereof, including seeds.
As aforementioned, agricultural compositions of the disclosure, which may comprise any microbe taught herein, are sometimes combined with one or more herbicides.
Compositions comprising bacteria or bacterial populations produced according to methods described herein and/or having characteristics as described herein may further include one or more herbicides. In some embodiments, herbicidal compositions are applied to the plants and/or plant parts. In some embodiments, herbicidal compositions may be included in the compositions set forth herein, and can be applied to a plant(s) or a part(s) thereof simultaneously or in succession, with other compounds.
Herbicides include 2,4-D, 2,4-DB, acetochlor, acifluorfen, alachlor, ametryn, atrazine, aminopyralid, benefin, bensulfuron, bensulide, bentazon, bicyclopyrone, bromacil, bromoxynil, butylate, carfentrazone, chlorimuron, chlorsulfuron, clethodim, clomazone, clopyralid, cloransulam, cycloate, DCPA, desmedipham, dicamba, dichlobenil, diclofop, diclosulam, diflufenzopyr, dimethenamid, diquat, diuron, DSMA, endothall, EPTC, ethalfluralin, ethofumesate, fenoxaprop, fluazifop-P, flucarbzone, flufenacet, flumetsulam, flumiclorac, flumioxazin, fluometuron, fluroxypyr, fomesafen, foramsulfuron, glufosinate, glyphosate, halosulfuron, hexazinone, imazamethabenz, imazamox, imazapic, imazaquin, imazethapyr, isoxaflutole, lactofen, linuron, MCPA, MCPB, mesotrione, metolachlor-s, metribuzin, indaziflam, metsulfuron, molinate, MSMA, napropamide, naptalam, nicosulfuron, norflurazon, oryzalin, oxadiazon, oxyfluorfen, paraquat, pelargonic acid, pendimethalin, phenmedipham, picloram, primisulfuron, prodiamine, prometryn, pronamide, propanil, prosulfuron, pyrazon, pyrithioac, quinclorac, quizalofop, rimsulfuron, S-metolachlor, sethoxydim, siduron, simazine, sulfentrazone, sulfometuron, sulfosulfuron, tebuthiuron, tembotrione, terbacil, thiazopyr, thifensulfuron, thiobencarb, topramezone, tralkoxydim, triallate, triasulfuron, tribenuron, triclopyr, trifluralin, and triflusulfuron.
In some embodiments, any one or more of the herbicides set forth herein may be utilized with any one or more of the plants or parts thereof set forth herein.
Herbicidal products may include CORVUS, BALANCE FLEXX, CAPRENO, DIFLEXX, LIBERTY, LAUDIS, AUTUMN SUPER, and DIFLEXX DUO.
In some embodiments, any one or more of the herbicides set forth in the below Table 12 may be utilized with any one or more of the microbes taught herein, and can be applied to any one or more of the plants or parts thereof set forth herein.
As aforementioned, agricultural compositions of the disclosure, which may comprise any microbe taught herein, are sometimes combined with one or more fungicides.
Compositions comprising bacteria or bacterial populations produced according to methods described herein and/or having characteristics as described herein may further include one or more fungicides. In some embodiments, fungicidal compositions may be included in the compositions set forth herein, and can be applied to a plant(s) or a part(s) thereof simultaneously or in succession, with other compounds. The fungicides include azoxystrobin, captan, carboxin, ethaboxam, fludioxonil, mefenoxam, fludioxonil, thiabendazole, thiabendaz, ipconazole, mancozeb, cyazofamid, zoxamide, metalaxyl, PCNB, metaconazole, pyraclostrobin, Bacillus subtilis strain QST 713, sedaxane, thiamethoxam, fludioxonil, thiram, tolclofos-methyl, trifloxystrobin, Bacillus subtilis strain MBI 600, pyraclostrobin, fluoxastrobin, Bacillus pumilus strain QST 2808, chlorothalonil, copper, flutriafol, fluxapyroxad, mancozeb, gludioxonil, penthiopyrad, triazole, propiconaozole, prothioconazole, tebuconazole, fluoxastrobin, pyraclostrobin, picoxystrobin, qols, tetraconazole, trifloxystrobin, cyproconazole, flutriafol, SDHI, EBDCs, sedaxane, MAXIM QUATTRO (gludioxonil, mefenoxam, azoxystrobin, and thiabendaz), RAXIL (tebuconazole, prothioconazole, metalaxyl, and ethoxylated tallow alkyl amines), and benzovindiflupyr.
In some embodiments, any one or more of the fungicides set forth herein may be utilized with any one or more of the plants or parts thereof set forth herein.
As aforementioned, agricultural compositions of the disclosure, which may comprise any microbe taught herein, are sometimes combined with one or more nematicides.
Compositions comprising bacteria or bacterial populations produced according to methods described herein and/or having characteristics as described herein may further include one or more nematicide. In some embodiments, nematicidal compositions may be included in the compositions set forth herein, and can be applied to a plant(s) or a part(s) thereof simultaneously or in succession, with other compounds. The nematicides may be selected from D-D, 1,3-dichloropropene, ethylene dibromide, 1,2-dibromo-3-chloropropane, methyl bromide, chloropicrin, metam sodium, dazomet, methylisothiocyanate, sodium tetrathiocarbonate, aldicarb, aldoxycarb, carbofuran, oxamyl, ethoprop, fenamiphos, cadusafos, fosthiazate, terbufos, fensulfothion, phorate, DiTera, clandosan, sincocin, methyl iodide, propargyl bromide, 2,5-dihydroxymethyl-3,4-dihydroxypyrrolidine (DMDP), any one or more of the avermectins, sodium azide, furfural, Bacillus firmus, abamectrin, thiamethoxam, fludioxonil, clothiandin, salicylic acid, and benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester.
In some embodiments, any one or more of the nematicides set forth herein may be utilized with any one or more of the plants or parts thereof set forth herein.
In some embodiments, any one or more of the nematicides, fungicides, herbicides, insecticides, and/or pesticides set forth herein may be utilized with any one or more of the plants or parts thereof set forth herein.
Fertilizers, Nitrogen Stabilizers, and Urease Inhibitors
As aforementioned, agricultural compositions of the disclosure, which may comprise any microbe taught herein, are sometimes combined with one or more of a: fertilizer, nitrogen stabilizer, or urease inhibitor.
In some embodiments, fertilizers are used in combination with the methods and bacteria of the present disclosure. Fertilizers include anhydrous ammonia, urea, ammonium nitrate, and urea-ammonium nitrate (UAN) compositions, among many others. In some embodiments, pop-up fertilization and/or starter fertilization is used in combination with the methods and bacteria of the present disclosure.
In some embodiments, nitrogen stabilizers are used in combination with the methods and bacteria of the present disclosure. Nitrogen stabilizers include nitrapyrin, 2-chloro (trichloromethyl) pyridine, N-SERVE 24, INSTINCT, dicyandiamide (DCD).
In some embodiments, urease inhibitors are used in combination with the methods and bacteria of the present disclosure. Urease inhibitors include N-(n-butyl)-thiophosphoric triamide (NBPT), AGROTAIN, AGROTAIN PLUS, and AGROTAIN PLUS SC. Further, the disclosure contemplates utilization of AGROTAIN ADVANCED 1.0, AGROTAIN DRI-MAXX, and AGROTAIN ULTRA.
Further, stabilized forms of fertilizer can be used. For example, a stabilized form of fertilizer is SUPER U, containing 46% nitrogen in a stabilized, urea-based granule, SUPERU contains urease and nitrification inhibitors to guard from dentrification, leaching, and volatilization. Stabilized and targeted foliar fertilizer such as NITAMIN may also be used herein.
Pop-up fertilizers are commonly used in corn fields. Pop-up fertilization comprises applying a few pounds of nutrients with the seed at planting. Pop-up fertilization is used to increase seedling vigor.
Slow- or controlled-release fertilizer that may be used herein entails: A fertilizer containing a plant nutrient in a form which delays its availability for plant uptake and use after application, or which extends its availability to the plant significantly longer than a reference ‘rapidly available nutrient fertilizer’ such as ammonium nitrate or urea, ammonium phosphate or potassium chloride. Such delay of initial availability or extended time of continued availability may occur by a variety of mechanisms. These include controlled water solubility of the material by semi-permeable coatings, occlusion, protein materials, or other chemical forms, by slow hydrolysis of water-soluble low molecular weight compounds, or by other unknown means.
Stabilized nitrogen fertilizer that may be used herein entails: A fertilizer to which a nitrogen stabilizer has been added. A nitrogen stabilizer is a substance added to a fertilizer which extends the time the nitrogen component of the fertilizer remains in the soil in the urea-N or ammoniacal-N form.
Nitrification inhibitor that may be used herein entails: A substance that inhibits the biological oxidation of ammoniacal-N to nitrate-N. Some examples include: (1) 2-chloro-6-(trichloromethyl-pyridine), common name Nitrapyrin, manufactured by Dow Chemical; (2) 4-amino-1,2,4-6-triazole-HCl, common name ATC, manufactured by Ishihada Industries; (3) 2,4-diamino-6-trichloro-methyltriazine, common name CI-1580, manufactured by American Cyanamid; (4) Dicyandiamide, common name DCD, manufactured by Showa Denko; (5) Thiourea, common name TU, manufactured by Nitto Ryuso; (6) 1-mercapto-1,2,4-triazole, common name MT, manufactured by Nippon; (7) 2-amino-4-chloro-6-methyl-pyramidine, common name AM, manufactured by Mitsui Toatsu; (8) 3,4-dimethylpyrazole phosphate (DMPP), from BASF; (9) 1-amide-2-thiourea (ASU), from Nitto Chemical Ind.; (10) Ammoniumthiosulphate (ATS); (11) 1H-1,2,4-triazole (HPLC); (12) 5-ethylene oxide trichloro-methlyl,2,4-thiodiazole (Terrazole), from Olin Mathieson; (13) 3-methylpyrazole (3-MP); (14) 1-carbamoyle-3-methyl-pyrazole (CMP); (15) Neem; and (16) DMPP.
Urease inhibitor that may be used herein entails: A substance that inhibits hydrolytic action on urea by the enzyme urease. Thousands of chemicals have been evaluated as soil urease inhibitors (Kiss and Simihaian, 2002). However, only a few of the many compounds tested meet the necessary requirements of being non toxic, effective at low concentration, stable, and compatible with urea (solid and solutions), degradable in the soil and inexpensive. They can be classified according to their structures and their assumed interaction with the enzyme urease (Watson, 2000, 2005). Four main classes of urease inhibitors have been proposed: (a) reagents which interact with the sulphydryl groups (sulphydryl reagents), (b) hydroxamates, (c) agricultural crop protection chemicals, and (d) structural analogues of urea and related compounds. N-(n-Butyl) thiophosphoric triamide (NBPT), phenylphosphorodiamidate (PPD/PPDA), and hydroquinone are probably the most thoroughly studied urease inhibitors (Kiss and Simihaian, 2002). Research and practical testing has also been carried out with N-(2-nitrophenyl) phosphoric acid triamide (2-NPT) and ammonium thiosulphate (ATS). The organo-phosphorus compounds are structural analogues of urea and are some of the most effective inhibitors of urease activity, blocking the active site of the enzyme (Watson, 2005).
Insecticidal Seed Treatments (ISTs) for Corn
Corn seed treatments normally target three spectrums of pests: nematodes, fungal seedling diseases, and insects.
Insecticide seed treatments are usually the main component of a seed treatment package. Most corn seed available today comes with a base package that includes a fungicide and insecticide. In some aspects, the insecticide options for seed treatments include PONCHO (clothianidin), CRUISER/CRUISER EXTREME (thiamethoxam) and GAUCHO (Imidacloprid). All three of these products are neonicotinoid chemistries. CRUISER and PONCHO at the 250 (0.25 mg AI/seed) rate are some of the most common base options available for corn. In some aspects, the insecticide options for treatments include CRUISER 250 thiamethoxam, CRUISER 250 (thiamethoxam) plus LUMIVIA (chlorantraniliprole), CRUISER 500 (thiamethoxam), and PONCHO VOTIVO 1250 (Clothianidin & Bacillus firmus
Pioneer's base insecticide seed treatment package consists of CRUISER 250 with PONCHO/VOTIVO 1250 also available. VOTIVO is a biological agent that protects against nematodes.
Monsanto's products including corn, soybeans, and cotton fall under the ACCELERON treatment umbrella. Dekalb corn seed comes standard with PONCHO 250. Producers also have the option to upgrade to PONCHO/VOTIVO, with PONCHO applied at the 500 rate.
Agrisure, Golden Harvest and Garst have a base package with a fungicide and CRUISER 250. AVICTA complete corn is also available; this includes CRUISER 500, fungicide, and nematode protection. CRUISER EXTREME is another option available as a seed treatment package, however; the amounts of CRUISER are the same as the conventional CRUISER seed treatment, i.e. 250, 500, or 1250.
Another option is to buy the minimum insecticide treatment available, and have a dealer treat the seed downstream.
Commercially available ISTs for corn are listed in the below Table 13 and can be combined with one or more of the microbes taught herein.
Bacillus pumilus
Bacillus subtilis
Streptomyces griseoviridis
Streptomyces lydicus
Trichoderma harzianum
Rifai
Bacillus firmus
Bacillus firmus
The composition of the bacteria or bacterial population described herein can be applied in furrow, in talc, or as seed treatment. The composition can be applied to a seed package in bulk, mini bulk, in a bag, or in talc.
The planter can plant the treated seed and grows the crop according to conventional ways, twin row, or ways that do not require tilling. The seeds can be distributed using a control hopper or an individual hopper. Seeds can also be distributed using pressurized air or manually. Seed placement can be performed using variable rate technologies. Additionally, application of the bacteria or bacterial population described herein may be applied using variable rate technologies. In some examples, the bacteria can be applied to seeds of corn, soybean, canola, sorghum, potato, rice, vegetables, cereals, pseudocereals, and oilseeds. Examples of cereals may include barley, fonio, oats, palmer's grass, rye, pearl millet, sorghum, spelt, teff, triticale, and wheat. Examples of pseudocereals may include breadnut, buckwheat, cattail, chia, flax, grain amaranth, hanza, quinoa, and sesame. In some examples, seeds can be genetically modified organisms (GMO), non-GMO, organic or conventional.
Additives such as micro-fertilizer, PGR, herbicide, insecticide, and fungicide can be used additionally to treat the crops. Examples of additives include crop protectants such as insecticides, nematicides, fungicide, enhancement agents such as colorants, polymers, pelleting, priming, and disinfectants, and other agents such as inoculant, PGR, softener, and micronutrients. PGRs can be natural or synthetic plant hormones that affect root growth, flowering, or stem elongation. PGRs can include auxins, gibberellins, cytokinins, ethylene, and abscisic acid (ABA).
The composition can be applied in furrow in combination with liquid fertilizer. In some examples, the liquid fertilizer may be held in tanks. NPK fertilizers contain macronutrients of sodium, phosphorous, and potassium.
The composition may improve plant traits, such as promoting plant growth, maintaining high chlorophyll content in leaves, increasing fruit or seed numbers, and increasing fruit or seed unit weight. Methods of the present disclosure may be employed to introduce or improve one or more of a variety of desirable traits. Examples of traits that may introduced or improved include: root biomass, root length, height, shoot length, leaf number, water use efficiency, overall biomass, yield, fruit size, grain size, photosynthesis rate, tolerance to drought, heat tolerance, salt tolerance, tolerance to low nitrogen stress, nitrogen use efficiency, resistance to nematode stress, resistance to a fungal pathogen, resistance to a bacterial pathogen, resistance to a viral pathogen, level of a metabolite, modulation in level of a metabolite, proteome expression. The desirable traits, including height, overall biomass, root and/or shoot biomass, seed germination, seedling survival, photosynthetic efficiency, transpiration rate, seed/fruit number or mass, plant grain or fruit yield, leaf chlorophyll content, photosynthetic rate, root length, or any combination thereof, can be used to measure growth, and compared with the growth rate of reference agricultural plants (e.g., plants without the introduced and/or improved traits) grown under identical conditions. In some examples, the desirable traits, including height, overall biomass, root and/or shoot biomass, seed germination, seedling survival, photosynthetic efficiency, transpiration rate, seed/fruit number or mass, plant grain or fruit yield, leaf chlorophyll content, photosynthetic rate, root length, or any combination thereof, can be used to measure growth, and compared with the growth rate of reference agricultural plants (e.g., plants without the introduced and/or improved traits) grown under similar conditions.
An agronomic trait to a host plant may include, but is not limited to, the following: altered oil content, altered protein content, altered seed carbohydrate composition, altered seed oil composition, and altered seed protein composition, chemical tolerance, cold tolerance, delayed senescence, disease resistance, drought tolerance, ear weight, growth improvement, health e4nhancement, heat tolerance, herbicide tolerance, herbivore resistance improved nitrogen fixation, improved nitrogen utilization, improved root architecture, improved water use efficiency, increased biomass, increased root length, increased seed weight, increased shoot length, increased yield, increased yield under water-limited conditions, kernel mass, kernel moisture content, metal tolerance, number of ears, number of kernels per ear, number of pods, nutrition enhancement, pathogen resistance, pest resistance, photosynthetic capability improvement, salinity tolerance, stay-green, vigor improvement, increased dry weight of mature seeds, increased fresh weight of mature seeds, increased number of mature seeds per plant, increased chlorophyll content, increased number of pods per plant, increased length of pods per plant, reduced number of wilted leaves per plant, reduced number of severely wilted leaves per plant, and increased number of non-wilted leaves per plant, a detectable modulation in the level of a metabolite, a detectable modulation in the level of a transcript, and a detectable modulation in the proteome, compared to an isoline plant grown from a seed without said seed treatment formulation.
In some cases, plants are inoculated with bacteria or bacterial populations that are isolated from the same species of plant as the plant element of the inoculated plant. For example, an bacteria or bacterial population that is normally found in one variety of Zea mays (corn) is associated with a plant element of a plant of another variety of Zea mays that in its natural state lacks said bacteria and bacterial populations. In one embodiment, the bacteria and bacterial populations is derived from a plant of a related species of plant as the plant element of the inoculated plant. For example, an bacteria and bacterial populations that is normally found in Zea diploperennis Iltis et al., (diploperennial teosinte) is applied to a Zea mays (corn), or vice versa. In some cases, plants are inoculated with bacteria and bacterial populations that are heterologous to the plant element of the inoculated plant. In one embodiment, the bacteria and bacterial populations is derived from a plant of another species. For example, bacteria and bacterial populations that are normally found in dicots are applied to a monocot plant (e.g., inoculating corn with a soybean-derived bacteria and bacterial populations), or vice versa. In other cases, the bacteria and bacterial populations to be inoculated onto a plant is derived from a related species of the plant that is being inoculated. In one embodiment, the bacteria and bacterial populations is derived from a related taxon, for example, from a related species. The plant of another species can be an agricultural plant. In another embodiment, the bacteria and bacterial populations is part of a designed composition inoculated into any host plant element.
In some examples, the bacteria or bacterial population is exogenous wherein the bacteria and bacterial population is isolated from a different plant than the inoculated plant. For example, in one embodiment, the bacteria or bacterial population can be isolated from a different plant of the same species as the inoculated plant. In some cases, the bacteria or bacterial population can be isolated from a species related to the inoculated plant.
In some examples, the bacteria and bacterial populations described herein are capable of moving from one tissue type to another. For example, the present disclosure's detection and isolation of bacteria and bacterial populations within the mature tissues of plants after coating on the exterior of a seed demonstrates their ability to move from seed exterior into the vegetative tissues of a maturing plant. Therefore, in one embodiment, the population of bacteria and bacterial populations is capable of moving from the seed exterior into the vegetative tissues of a plant. In one embodiment, the bacteria and bacterial populations that is coated onto the seed of a plant is capable, upon germination of the seed into a vegetative state, of localizing to a different tissue of the plant. For example, bacteria and bacterial populations can be capable of localizing to any one of the tissues in the plant, including: the root, adventitious root, seminal 5 root, root hair, shoot, leaf, flower, bud, tassel, meristem, pollen, pistil, ovaries, stamen, fruit, stolon, rhizome, nodule, tuber, trichome, guard cells, hydathode, petal, sepal, glume, rachis, vascular cambium, phloem, and xylem. In one embodiment, the bacteria and bacterial populations is capable of localizing to the root and/or the root hair of the plant. In another embodiment, the bacteria and bacterial populations is capable of localizing to the photosynthetic tissues, for example, leaves and shoots of the plant. In other cases, the bacteria and bacterial populations is localized to the vascular tissues of the plant, for example, in the xylem and phloem. In still another embodiment, the bacteria and bacterial populations is capable of localizing to the reproductive tissues (flower, pollen, pistil, ovaries, stamen, fruit) of the plant. In another embodiment, the bacteria and bacterial populations is capable of localizing to the root, shoots, leaves and reproductive tissues of the plant. In still another embodiment, the bacteria and bacterial populations colonizes a fruit or seed tissue of the plant. In still another embodiment, the bacteria and bacterial populations is able to colonize the plant such that it is present in the surface of the plant (i.e., its presence is detectably present on the plant exterior, or the episphere of the plant). In still other embodiments, the bacteria and bacterial populations is capable of localizing to substantially all, or all, tissues of the plant. In certain embodiments, the bacteria and bacterial populations is not localized to the root of a plant. In other cases, the bacteria and bacterial populations is not localized to the photosynthetic tissues of the plant.
The effectiveness of the compositions can also be assessed by measuring the relative maturity of the crop or the crop heating unit (CHU). For example, the bacterial population can be applied to corn, and corn growth can be assessed according to the relative maturity of the corn kernel or the time at which the corn kernel is at maximum weight. The crop heating unit (CHU) can also be used to predict the maturation of the corn crop. The CHU determines the amount of heat accumulation by measuring the daily maximum temperatures on crop growth.
In examples, bacterial may localize to any one of the tissues in the plant, including: the root, adventitious root, seminal root, root hair, shoot, leaf, flower, bud tassel, meristem, pollen, pistil, ovaries, stamen, fruit, stolon, rhizome, nodule, tuber, trichome, guard cells, hydathode, petal, sepal, glume, rachis, vascular cambium, phloem, and xylem. In another embodiment, the bacteria or bacterial population is capable of localizing to the photosynthetic tissues, for example, leaves and shoots of the plant. In other cases, the bacteria and bacterial populations is localized to the vascular tissues of the plant, for example, in the xylem and phloem. In another embodiment, the bacteria or bacterial population is capable of localizing to reproductive tissues (flower, pollen, pistil, ovaries, stamen, or fruit) of the plant. In another embodiment, the bacteria and bacterial populations is capable of localizing to the root, shoots, leaves and reproductive tissues of the plant. In another embodiment, the bacteria or bacterial population colonizes a fruit or seed tissue of the plant. In still another embodiment, the bacteria or bacterial population is able to colonize the plant such that it is present in the surface of the plant. In another embodiment, the bacteria or bacterial population is capable of localizing to substantially all, or all, tissues of the plant. In certain embodiments, the bacteria or bacterial population is not localized to the root of a plant. In other cases, the bacteria and bacterial populations is not localized to the photosynthetic tissues of the plant.
The effectiveness of the bacterial compositions applied to crops can be assessed by measuring various features of crop growth including, but not limited to, planting rate, seeding vigor, root strength, drought tolerance, plant height, dry down, and test weight.
The methods and bacteria described herein are suitable for any of a variety of plants, such as plants in the genera Hordeum, Oryza, Zea, and Triticeae. Other non-limiting examples of suitable plants include mosses, lichens, and algae. In some cases, the plants have economic, social and/or environmental value, such as food crops, fiber crops, oil crops, plants in the forestry or pulp and paper industries, feedstock for biofuel production and/or ornamental plants. In some examples, plants may be used to produce economically valuable products such as a grain, a flour, a starch, a syrup, a meal, an oil, a film, a packaging, a nutraceutical product, a pulp, an animal feed, a fish fodder, a bulk material for industrial chemicals, a cereal product, a processed human-food product, a sugar, an alcohol, and/or a protein. Non-limiting examples of crop plants include maize, rice, wheat, barley, sorghum, millet, oats, rye triticale, buckwheat, sweet corn, sugar cane, onions, tomatoes, strawberries, and asparagus. In some embodiments, the methods and bacteria described herein are suitable for any of a variety of transgenic plants, non-transgenic plants, and hybrid plants thereof.
In some examples, plants that may be obtained or improved using the methods and composition disclosed herein may include plants that are important or interesting for agriculture, horticulture, biomass for the production of biofuel molecules and other chemicals, and/or forestry. Some examples of these plants may include pineapple, banana, coconut, lily, grasspeas and grass; and dicotyledonous plants, such as, for example, peas, alfalfa, tomatillo, melon, chickpea, chicory, clover, kale, lentil, soybean, tobacco, potato, sweet potato, radish, cabbage, rape, apple trees, grape, cotton, sunflower, thale cress, canola, citrus (including orange, mandarin, kumquat, lemon, lime, grapefruit, tangerine, tangelo, citron, and pomelo), pepper, bean, lettuce, Panicum virgatum (switch), Sorghum bicolor (sorghum, sudan), Miscanthus giganteus (miscanthus), Saccharum sp. (energycane), Populus balsamifera (poplar), Zea mays (corn), Glycine max (soybean), Brassica napus (canola), Triticum aestivum (wheat), Gossypium hirsutum (cotton), Oryza sativa (rice), Helianthus annuus (sunflower), Medicago sativa (alfalfa), Beta vulgaris (sugarbeet), Pennisetum glaucum (pearl millet), Panicum spp. Sorghum spp., Miscanthus spp., Saccharum spp., Erianthus spp., Populus spp., Secale cereale (rye), Salix spp. (willow), Eucalyptus spp. (eucalyptus), Triticosecale spp. (triticum- 25 wheat X rye), Bamboo, Carthamus tinctorius (safflower), Jatropha curcas (Jatropha), Ricinus communis (castor), Elaeis guineensis (oil palm), Phoenix dactylifera (date palm), Archontophoenix cunninghamiana (king palm), Syagrus romanzoffiana (queen palm), Linum usitatissimum (flax), Brassica juncea, Manihot esculenta (cassaya), Lycopersicon esculentum (tomato), Lactuca saliva (lettuce), Musa paradisiaca (banana), Solanum tuberosum (potato), Brassica oleracea (broccoli, cauliflower, brussel sprouts), Camellia sinensis (tea), Fragaria ananassa (strawberry), Theobroma cacao (cocoa), Coffea arabica (coffee), Vitis vinifera (grape), Ananas comosus (pineapple), Capsicum annum (hot & sweet pepper), Allium cepa (onion), Cucumis melo (melon), Cucumis sativus (cucumber), Cucurbita maxima (squash), Cucurbita moschata (squash), Spinacea oleracea (spinach), Citrullus lanatus (watermelon), Abelmoschus esculentus (okra), Solanum melongena (eggplant), Papaver somniferum (opium poppy), Papaver orientale, Taxus baccata, Taxus brevifolia, Artemisia annua, Cannabis saliva, Camptotheca acuminate, Catharanthus roseus, Vinca rosea, Cinchona officinalis, Coichicum autumnale, Veratrum californica, Digitalis lanata, Digitalis purpurea, Dioscorea 5 spp., Andrographis paniculata, Atropa belladonna, Datura stomonium, Berberis spp., Cephalotaxus spp., Ephedra sinica, Ephedra spp., Erythroxylum coca, Galanthus wornorii, Scopolia spp., Lycopodium serratum (Huperzia serrata), Lycopodium spp., Rauwolfia serpentina, Rauwolfia spp., Sanguinaria canadensis, Hyoscyamus spp., Calendula officinalis, Chrysanthemum parthenium, Coleus forskohlii, Tanacetum parthenium, Parthenium argentatum (guayule), Hevea spp. (rubber), Mentha spicata (mint), Mentha piperita (mint), Bixa orellana, Alstroemeria spp., Rosa spp. (rose), Dianthus caryophyllus (carnation), Petunia spp. (petunia), Poinsettia pulcherrima (poinsettia), Nicotiana tabacum (tobacco), Lupinus albus (lupin), Uniola paniculata (oats), Hordeum vulgare (barley), and Lolium spp. (rye).
In some examples, a monocotyledonous plant may be used. Monocotyledonous plants belong to the orders of the Alismatales, Arales, Arecales, Bromeliales, Commelinales, Cyclanthales, Cyperales, Eriocaulales, Hydrocharitales, Juncales, Lilliales, Najadales, Orchidales, Pandanales, Poales, Restionales, Triuridales, Typhales, and Zingiberales. Plants belonging to the class of the Gymnospermae are Cycadales, Ginkgoales, Gnetales, and Pinales. In some examples, the monocotyledonous plant can be selected from the group consisting of a maize, rice, wheat, barley, and sugarcane.
In some examples, a dicotyledonous plant may be used, including those belonging to the orders of the Aristochiales, Asterales, Batales, Campanulales, Capparales, Caryophyllales, Casuarinales, Celastrales, Cornales, Diapensales, Dilleniales, Dipsacales, Ebenales, Ericales, Eucomiales, Euphorbiales, Fabales, Fagales, Gentianales, Geraniales, Haloragales, Hamamelidales, Middles, Juglandales, Lamiales, Laurales, Lecythidales, Leitneriales, Magniolales, Malvales, Myricales, Myrtales, Nymphaeales, Papeverales, Piperales, Plantaginales, Plumb aginales, Podostemales, Polemoniales, Polygalales, Polygonales, Primulales, Proteales, Rafflesiales, Ranunculales, Rhamnales, Rosales, Rubiales, Salicales, Santales, Sapindales, Sarraceniaceae, Scrophulariales, Theales, Trochodendrales, Umbellales, Urticales, and Violates. In some examples, the dicotyledonous plant can be selected from the group consisting of cotton, soybean, pepper, and tomato.
In some cases, the plant to be improved is not readily amenable to experimental conditions. For example, a crop plant may take too long to grow enough to practically assess an improved trait serially over multiple iterations. Accordingly, a first plant from which bacteria are initially isolated, and/or the plurality of plants to which genetically manipulated bacteria are applied may be a model plant, such as a plant more amenable to evaluation under desired conditions. Non-limiting examples of model plants include Setaria, Brachypodium, and Arabidopsis. Ability of bacteria isolated according to a method of the disclosure using a model plant may then be applied to a plant of another type (e.g. a crop plant) to confirm conferral of the improved trait.
Traits that may be improved by the methods disclosed herein include any observable characteristic of the plant, including, for example, growth rate, height, weight, color, taste, smell, changes in the production of one or more compounds by the plant (including for example, metabolites, proteins, drugs, carbohydrates, oils, and any other compounds). Selecting plants based on genotypic information is also envisaged (for example, including the pattern of plant gene expression in response to the bacteria, or identifying the presence of genetic markers, such as those associated with increased nitrogen fixation). Plants may also be selected based on the absence, suppression or inhibition of a certain feature or trait (such as an undesirable feature or trait) as opposed to the presence of a certain feature or trait (such as a desirable feature or trait).
The methods and bacteria described herein are suitable for any of a variety of non-genetically modified maize plants or part thereof. And in some aspects, the corn is organic. Furthermore, the methods and bacteria described herein are suitable for any of the following non-genetically modified hybrids, varieties, lineages, etc. In some embodiments, corn varieties generally fall under six categories: sweet corn, flint corn, popcorn, dent corn, pod corn, and flour corn.
Yellow su varieties include Earlivee, Early Sunglow, Sundance, Early Golden Bantam, Iochief, Merit, Jubilee, and Golden Cross Bantam. White su varieties include True Platinum, Country Gentleman, Silver Queen, and Stowell's Evergreen. Bicolor su varieties include Sugar & Gold, Quickie, Double Standard, Butter & Sugar, Sugar Dots, Honey & Cream. Multicolor su varieties include Hookers, Triple Play, Painted Hill, Black Mexican/Aztec.
Yellow se varieties include Buttergold, Precocious, Spring Treat, Sugar Buns, Colorow, Kandy King, Bodacious R/M, Tuxedo, Incredible, Merlin, Miracle, and Kandy Korn E H. White se varieties include Spring Snow, Sugar Pearl, Whiteout, Cloud Nine, Alpine, Silver King, and Argent. Bicolor se varieties include Sugar Baby, Fleet, Bon Jour, Trinity, Bi-Licious, Temptation, Luscious, Ambrosia, Accord, Brocade, Lancelot, Precious Gem, Peaches and Cream Mid EH, and Delectable R/M. Multicolor se varieties include Ruby Queen.
Yellow sh2 varieties include Extra Early Super Sweet, Takeoff, Early Xtra Sweet, Raveline, Summer Sweet Yellow, Krispy King, Garrison, Illini Gold, Challenger, Passion, Excel, Jubilee SuperSweet, Illini Xtra Sweet, and Crisp 'N Sweet. White sh2 varieties include Summer Sweet White, Tahoe, Aspen, Treasure, How Sweet It Is, and Camelot. Bicolor sh2 varieties include Summer Sweet Bicolor, Radiance, Honey 'N Pearl, Aloha, Dazzle, Hudson, and Phenomenal.
Yellow sy varieties include Applause, Inferno, Honeytreat, and Honey Select. White sy varieties include Silver Duchess, Cinderella, Mattapoisett, Avalon, and Captivate. Bicolor sy varieties include Pay Dirt, Revelation, Renaissance, Charisma, Synergy, Montauk, Kristine, Serendipity/Providence, and Cameo.
Yellow augmented supersweet varieties include Xtra-Tender 1ddA, Xtra-Tender 11dd, Mirth 131Y, Mirai 130Y, Vision, and Mirai 002. White augmented supersweet varieties include Xtra-Tender 3dda, Xtra-Tender 31dd, Mirai 421W, XTH 3673, and Devotion. Bicolor augmented supersweet varieties include Xtra-Tender 2dda, Xtra-Tender 21dd, Kickoff XR, Mirth 308BC, Anthem XR, Mirai 336BC, Fantastic XR, Triumph, Mirai 301BC, Stellar, American Dream, Mirai 350BC, and Obsession.
Flint corn varieties include Bronze-Orange, Candy Red Flint, Floriani Red Flint, Glass Gem, Indian Ornamental (Rainbow), Mandan Red Flour, Painted Mountain, Petmecky, Cherokee White Flour,
Pop corn varieties include Monarch Butterfly, Yellow Butterfly, Midnight Blue, Ruby Red, Mixed Baby Rice, Queen Mauve, Mushroom Flake, Japanese Hull-less, Strawberry, Blue Shaman, Miniature Colored, Miniature Pink, Pennsylvania Dutch Butter Flavor, and Red Strawberry.
Dent corn varieties include Bloody Butcher, Blue Clarage, Ohio Blue Clarage, Cherokee White Eagle, Hickory Cane, Hickory King, Jellicorse Twin, Kentucky Rainbow, Daymon Morgan's Knt. Butcher, Leaming, Leaming's Yellow, McCormack's Blue Giant, Neal Paymaster, Pungo Creek Butcher, Reid's Yellow Dent, Rotten Clarage, and Tennessee Red Cob.
In some embodiments, corn varieties include P1618W, P1306W, P1345, P1151, P1197, P0574, P0589, and P0157. W=white corn.
In some embodiments, the methods and bacteria described herein are suitable for any hybrid of the maize varieties setforth herein.
The methods and bacteria described herein are suitable for any of a hybrid, variety, lineage, etc. of genetically modified maize plants or part thereof.
Furthermore, the methods and bacteria described herein are suitable for any of the following genetically modified maize events, which have been approved in one or more countries: 32138 (32138 SPT Maintainer), 3272 (ENOGEN), 3272×Bt11, 3272×bt11×GA21, 3272×Bt11×MIR604, 3272×Bt11×MIR604×GA21, 3272×Bt11×MIR604×TC1507×5307×GA21, 3272×GA21, 3272×MIR604, 3272×MIR604×GA21, 4114, 5307 (AGRISURE Duracade), 5307×GA21, 5307×MIR604×Bt11×TC1507×GA21 (AGRISURE Duracade 5122), 5307×MIR604×Bt11×TC1507×GA21×MIR162 (AGRISURE Duracade 5222), 59122 (HERCULEX RW), 59122×DAS40278, 59122×GA21, 59122×MIR604, 59122×MIR604×GA21, 59122×MIR604×TC1507, 59122×MIR604×TC1507×GA21, 59122×MON810, 59122×MON810×MIR604, 59122×MON810×NK603, 59122×MON810×NK603×MIR604, 59122×MON88017, 59122×MON88017×DAS40278, 59122×NK603 (Herculex RW ROUNDUP READY 2), 59122×NK603×MIR604, 59122×TC1507×GA21, 676, 678, 680, 3751 IR, 98140, 98140×59122, 98140×TC1507, 98140×TC1507×59122, Bt10 (Bt10), Bt11 [X4334CBR, X4734CBR] (AGRISURE CB/LL), Bt11×5307, Bt11×5307×GA21, Bt11×59122×MIR604, Br11×59122×MIR604×GA21, Bt11×59122×MIR604×TC1507, M53, M56, DAS-59122-7, Bt11×59122×MIR604×TC1507×GA21, Bt11×59122×TC1507, TC1507×DAS-59122-7, Bt11×59122×TC1507×GA21, Bt11×GA21 (AGRISURE GT/CB/LL), Bt11×MIR162 (AGRISURE Viptera 2100), BT11×MIR162×5307, Bt11×MIR162×5307×GA21, Bt11×MIR162×GA21 (AGRISURE Viptera 3110), Bt11×MIR162×MIR604 (AGRISURE Viptera 3100), Bt11×MIR162×MIR604×5307, Bt11×MIR162×MIR604×5307×GA21, Bt11×MIR162×MIR604×GA21 (AGRISURE Viptera 3111/AGRISURE Viptera 4), Bt11, MIR162×MIR604×MON89034×5307×GA21, Bt11×MIR162×MIR604×TC1507, Bt11×MIR162×MIR604×TC1507×5307, Bt11×MIR162×MIR604×TC1507×GA21, Bt11×MIR162×MON89034, Bt11×MIR162×MON89034×GA21, Bt11×MIR162×TC1507, Bt11×MIR162×TC1507×5307, Bt11×MIR162×TC1507×5307×GA21, Bt11×MR162×TC1507×GA21 (AGRISURE Viptera 3220), BT11×MIR604 (Agrisure BC/LL/RW), Bt11×MIR604×5307, Bt11×MIR604×5307×GA21, Bt11×MIR604×GA21, Bt11×MIR604×TC1507, Bt11×MIR604×TC1507×5307, Bt11×MIR604×TC1507×GA21, Bt11×MON89034×GA21, Bt11×TC1507, Bt11×TC1507×5307, Bt11×TC1507×GA21, Bt176 (NaturGard KnockOut/Maximizer), BVLA430101, CBH-351 (STARLINK Maize), DAS40278 (ENLIST Maize), DAS40278×NK603, DBT418 (Bt Xtra Maize), DLL25 [B16], GA21 (ROUNDUP READY Maize/AGRISURE GT), GA21×MON810 (ROUNDUP READY Yieldgard Maize), GA21×T25, HCEM485, LY038 (MAVERA Maize), LY038×MON810 (MAVERA Yieldgard Maize), MIR162 (AGRISURE Viptera), MIR162×5307, MIR162×5307×GA21, MIR162×GA21, MIR162×MIR604, MIR162×MIR604×5307, MIR162×MIR604×5307×GA21, MIR162×MIR604×GA21, MIR162×MIR604×TC1507×5307, MIR162×MIR604×TC1507×5307×GA21, MIR162×MIR604×TC1507×GA21, MIR162×MON89034, MIR162×NK603, MIR162×TC1507, MIR162×TC1507×5307, MIR162×TC1507×5307×GA21, MIR162×TC1507×GA21, MIR604 (AGRISURE RW), MIR604×5307, MIR604×5307×GA21, MIR604×GA21 (AGRISURE GT/RW), MIR604×NK603, MIR604×TC1507, MIR604×TC1507×5307, MIR604×TC1507×5307×GA21, MIR604×TC1507×GA21, MON801 [MON80100], MON802, MON809, MON810 (YIELDGARD, MAIZEGARD), MON810×MIR162, MON810×MIR162×NK603, MON810×MIR604, MON810×MON88017 (YIELDGARD VT Triple), MON810×NK603×MIR604, MON832 (ROUNDUP READY Maize), MON863 (YIELDGARD Rootworm RW, MAXGARD), MON863×MON810 (YIELDGARD Plus), MON863×MON810×NK603 (YIELDGARD Plus with RR), MON863×NK603 (YIELDGARD RW+RR), MON87403, MON87411, MON87419, MON87427 (ROUNDUP READY Maize), MON87427×59122, MON87427×MON88017, MON87427×MON88017×59122, MON87427×MON89034, MON87427×MON89034×59122, MON87427×MON89034×MIR162×MON87411, MON87427×MON89034×MON88017, MON87427×MON89034×MON88017×59122, MON87427×MON89034×NK603, MON87427×MON89034×TC1507, MON87427×MON89034×TC1507×59122, MON87427×MON89034×TC1507×MON87411×59122, MON87427×MON89034×TC1507×MON87411×59122×DAS40278, MON87427×MON89034×TC1507×MON88017, MON87427×MON89034×MIR162×NK603, MON87427×MON89034×TC1507×MON88017×59122, MON87427×TC1507, MON87427×TC1507×59122, MON87427×TC1507×MON88017, MON87427×TC1507×MON88017×59122, MON87460 (GENUITY DROUGHTGARD), MON87460×MON88017, MON87460×MON89034×MON88017, MON87460×MON89034×NK603, MON87460×NK603, MON88017, MON88017×DAS40278, MON89034, MON89034×59122, MON89034×59122×DAS40278, MON89034×59122×MON88017, MON89034×59122×MON88017×DAS40278, MON89034×DAS40278, MON89034×MON87460, MON89034×MON88017 (GENUITY VT Triple Pro), MON89034×MON88017×DAS40278, MON89034×NK603 (GENUITY VT Double Pro), MON89034×NK603×DAS40278, MON89034×TC1507, MON89034×TC1507×59122, MON89034×TC1507×59122×DAS40278, MON89034×TC1507×DAS40278, MON89034×TC1507×MON88017, MON89034×TC1507×MON88017×59122 (GENUITY SMARTSTAX), MON89034×TC1507×MON88017×59122×DAS40278, MON89034×TC1507×MON88017×DAS40278, MON89034×TC1507×NK603 (POWER CORE), MON89034×TC1507×NK603×DAS40278, MON89034×TC1507×NK603×MIR162, MON89034×TC1507×NK603×MIR162×DAS40278, MON89034×GA21, MS3 (INVIGOR Maize), MS6 (INVIGOR Maize), MZHGOJG, MZIR098, NK603 (ROUNDUP READY 2 Maize), NK603×MON810×4114×MIR604,NK603×MON810 (YIELDGARD CB+RR), NK603×T25 (ROUNDUP READY LIBERTY LINK Maize), T14 (LIBERTY LINK Maize), T25 (LIBERTY LINK Maize), T25×MON810 (LIBERTY LINK YIELDGARD Maize), TC1507 (HERCULEX I, HERCULEX CB), TC1507×59122×MON810×MIR604×NK603 (OPTIMUM INTRASECT XTREME), TC1507×MON810×MIR604×NK603, TC1507×5307, TC1507×5307×GA21, TC1507×59122 (HERCULEX XTRA), TC1507×59122×DAS40278, TC1507×59122×MON810, TC1507×59122×MON810×MIR604, TC1507×59122×MON810×NK603 (OPTIMUM INTRASECT XTRA), TC1507×59122×MON88017, TC1507×59122×MON88017×DAS40278, TC1507×59122×NK603 (HERCULEX XTRA RR), TC1507×59122×NK603×MIR604, TC1507×DAS40278, TC1507×GA21, TC1507×MIR162×NK603, TC1507×MIR604×NK603 (OPTIMUM TRISECT), TC1507×MON810, TC1507×MON810×MIR162, TC1507×MON810×MIR162×NK603, TC1507×MON810×MIR604, TC1507×MON810×NK603 (OPTIMUM INTRASECT), TC1507×MON810×NK603×MIR604, TC1507×MON88017, TC1507×MON88017×DAS40278, TC1507×NK603 (HERCULEX I RR), TC1507×NK603×DAS40278, TC6275, and VCO-01981-5.
The methods and bacteria described herein are suitable for any of a variety of genetically modified plants or part thereof.
Furthermore, the methods and bacteria described herein are suitable for any of the following genetically modified plant events which have been approved in one or more countries.
Oryza sativa Rice
Streptomyces hygroscopicus).
Streptomyces hygroscopicus).
Medicago sativa Alfalfa
Agrobacterium tumefaciens.
Triticum aestivum Wheat
tumefaciens, strain CP4.
Helianthus annuus Sunflower
Glycine max L. Soybean
viridochromogenes.
viridochromogenes.
Arabidopsis thaliana encodes an
tumefaciens.
viridochromogenes.
includens).
includens) via expression of the
thuringiensis.
Agrobacterium tumefaciens CP4.
hygroscopicus.
Zea mays L. Maize
Bacillus thuringiensis subsp.
kurstaki. The genetic modification
Escherichia coli and Streptomyces
viridochromogenes, respectively.
hygroscopicus.
Bacillus thuringiensis subsp.
kurstaki, and the phosphinothricin
viridochromogenes.
frugiperda), and black cutworm
Bacillus thuringiensis subsp.
kurstaki, and the phosphinothricin
viridochromogenes. Resistance to
H. zea, S. frugiperda, A. ipsilon,
thuringiensis strain AB88.
Bacillus thuringiensis Cry1Ab
thuringiensis Vip3Aa20
tolworthi and phosphinothricin
Streptomyces hygroscopicus.
Bacillus thuringiensis var aizawai
Streptomyces hygroscopicus.
Bacillus thuringiensis subsp.
kurstaki, and the phosphinothricin
viridochromogenes. Corn
thuringiensis.
Bacillus thuringiensis subsp.
kurstaki, and the phosphinothricin
viridochromogenes. Corn
thuringiensis. Tolerance to
viridochromogenes was introduced
thuringiensis strain P5149B1.
kurstaki and phosphinothricin
Streptomyces hygroscopicus.
thuringiensis. Tolerance to
Bacillus thuringiensis subsp.
kurstaki. The genetic modification
thuringiensis and the 5-
tumefaciens strain CP4.
thuringiensis subsp. kurstaki HD-
kurstaki HD-1 present in
thuringiensis subspecies
kumamotoensis strain EG4691
subtilis cold shock protein B
Bacillus thuringiensis providing
Agrobacterium tumefaciens
thuringiensis var. aizawai and the
viridochromogenes.
Bacillus thuringiensis var. aizawai.
thuringiensis strain P5149B1.
viridochromogenes.
The following are the definitions for the shorthand occurring in Table 19. AM—OPTIMUM ACREMAX Insect Protection system with YGCB, HX1, LL, RR2. AMT—OPTIMUM ACREMAX TRISECT Insect Protection System with RW,YGCB,HX1,LL,RR2. AMXT—(OPTIMUM ACREMAX XTreme). HXX—HERCULEX XTRA contains the Herculex I and Herculex RW genes. HX1—Contains the HERCULEX I Insect Protection gene which provides protection against European corn borer, southwestern corn borer, black cutworm, fall armyworm, western bean cutworm, lesser corn stalk borer, southern corn stalk borer, and sugarcane borer; and suppresses corn earworm. LL—Contains the LIBERTYLINK gene for resistance to LIBERTY herbicide. RR2-Contains the ROUNDUP READY Corn 2 trait that provides crop safety for over-the-top applications of labeled glyphosate herbicides when applied according to label directions. YGCB—contains the YIELDGARD Corn Borer gene offers a high level of resistance to European corn borer, southwestern corn borer, and southern cornstalk borer; moderate resistance to corn earworm and common stalk borer; and above average resistance to fall armyworm. RW—contains the AGRISURE root worm resistance trait. Q—provides protection or suppression against susceptible European corn borer, southwestern corn borer, black cutworm, fall armyworm, lesser corn stalk borer, southern corn stalk borer, stalk borer, sugarcane borer, and corn earworm; and also provides protection from larval injury caused by susceptible western corn rootworm, northern corn rootworm, and Mexican corn rootworm; contains (1) HERCULEX XTRA Insect Protection genes that produce Cry1F and Cry34ab1 and Cry35ab1 proteins, (2) AGRISURE RW trait that includes a gene that produces mCry3A protein, and (3) YIELDGARD Corn Borer gene which produces Cry1Ab protein.
As aforementioned, the agricultural compositions of the present disclosure, which comprise a taught microbe, can be applied to plants in a multitude of ways. In two particular aspects, the disclosure contemplates an in-furrow treatment or a seed treatment
For seed treatment embodiments, the microbes of the disclosure can be present on the seed in a variety of concentrations. For example, the microbes can be found in a seed treatment at a cfu concentration, per seed of: 1×101, 1×102, 1×103, 1×104, 1×105, 1×106, 1×107, 1×108, 1×109, 1×1010, or more. In particular aspects, the seed treatment compositions comprise about 1×104 to about 1×108 cfu per seed. In other particular aspects, the seed treatment compositions comprise about 1×105 to about 1×107 cfu per seed. In other aspects, the seed treatment compositions comprise about 1×106 cfu per seed.
In the United States, about 10% of corn acreage is planted at a seed density of above about 36,000 seeds per acre; ⅓ of the corn acreage is planted at a seed density of between about 33,000 to 36,000 seeds per acre; ⅓ of the corn acreage is planted at a seed density of between about 30,000 to 33,000 seeds per acre, and the remainder of the acreage is variable. See, “Corn Seeding Rate Considerations,” written by Steve Butzen, available at: www.pioneer.com/home/site/us/agronomy/library/corn-seeding-rate-considerations/
Table 20 below utilizes various cfu concentrations per seed in a contemplated seed treatment embodiment (rows across) and various seed acreage planting densities (1st column: 15K-41K) to calculate the total amount of cfu per acre, which would be utilized in various agricultural scenarios (i.e. seed treatment concentration per seed×seed density planted per acre). Thus, if one were to utilize a seed treatment with 1×106 cfu per seed and plant 30,000 seeds per acre, then the total cfu content per acre would be 3×1010 (i.e. 30K*1×106).
For in-furrow embodiments, the microbes of the disclosure can be applied at a cfu concentration per acre of: 1×106, 3.20×1010, 1.60×1011, 3.20×1011, 8.0×1011, 1.6×1012, 3.20×1012, or more. Therefore, in aspects, the liquid in-furrow compositions can be applied at a concentration of between about 1×106 to about 3×1012 cfu per acre.
In some aspects, the in-furrow compositions are contained in a liquid formulation. In the liquid in-furrow embodiments, the microbes can be present at a cfu concentration per milliliter of: 1×101, 1×102, 1×103, 1×104, 1×105, 1×106, 1×107, 1×108, 1×109, 1×1010, 1×1011, 1×1012, 1×1013, or more. In certain aspects, the liquid in-furrow compositions comprise microbes at a concentration of about 1×106 to about 1×1011 cfu per milliliter. In other aspects, the liquid in-furrow compositions comprise microbes at a concentration of about 1×107 to about 1×1010 cfu per milliliter. In other aspects, the liquid in-furrow compositions comprise microbes at a concentration of about 1×108 to about 1×109 cfu per milliliter. In other aspects, the liquid in-furrow compositions comprise microbes at a concentration of up to about 1×1013 cfu per milliliter.
Previous work by the inventors entailed transcriptomic profiling of strain CI010 to identify promoters that are active in the presence of environmental nitrogen. Strain CI010 was cultured in a defined, nitrogen-free media supplemented with 10 mM glutamine. Total RNA was extracted from these cultures (QIAGEN RNeasy kit) and subjected to RNAseq sequencing via Illumina HiSeq (SeqMatic, Fremont Calif.). Sequencing reads were mapped to the CI010 genome data using Geneious, and highly expressed genes under control of proximal transcriptional promoters were identified.
Tables 21-23 list genes and their relative expression level as measured through RNASeq sequencing of total RNA. Sequences of the proximal promoters were recorded for use in mutagenesis of nif pathways, nitrogen utilization related pathways, or other genes with a desired expression level.
The present disclosure provides compositions of more than one type of microorganism for the provision of nitrogen to a target plant. The entirety of the present disclosure as it applies to individual microbes is explicitly intended to apply to combinations, or consortia, of microbes, as well. In some embodiments, at least two of the microorganisms comprised by the consortium may differ along one or more dimensions. Exemplary dimensions include nutrient utilization, spatial occupation, temporal occupation, and oxygen adaptability.
Also provided are methods for the selection of microorganisms for inclusion in microbial consortia according to the present disclosure.
In some embodiments, the disclosure provides synthetic compositions of microbes and methods for the selection thereof. A “synthetic composition” as used herein refers to a deliberately assembled combination of microbes that may not naturally occur within the context of a target plant to which the combination is intended to be applied. For example, a synthetic composition of microbes as it applies to corn plants may include any combination of microbes that does not naturally occur in/on/closely associated with a corn plant.
In some embodiments, the combination of microbes may be naturally occurring, but the combination is manipulated in some way to distinguish it from its naturally occurring state. For example, the combination may be isolated from nature, expanded in population, formulated, and reapplied to a crop at a concentration not naturally found. The formulation itself may also distinguish the combination of microbes from naturally existing combinations of microbes. The formulation may include other agents, such as, but not limited to, stabilizing agents, spray-drying agents, pesticides, herbicides, insecticides, fertilizers, or any other such additive useful for the formulation of a substance for application to a plant or its seeds, such as any one or more of those listed herein.
In some embodiments, at least two microbes within the consortium differ in terms of nutrient utilization, e.g., carbon source or nitrogen source utilization. In some embodiments, the microbes may differ in their utilization of an amino acid, amine, amide, or peptide. In some embodiments, the microbes may differ in their utilization of a simple or complex carbohydrate, organic acid, or carboxylic acid.
In some embodiments, the carbon source utilization of a given microbe may depend on other factors, e.g., environmental factors. For example, the carbon or nitrogen source utilization of a microbe may vary depending on oxygen availability. In some embodiments, the microbes are selected to differ in terms of nutrient utilization in the context of the oxygenation environment they would be expected to experience within the plant's rhizosphere, on the plant's surface, or closely associated with the plant. More generally, microbes may be selected for inclusion in the consortium based not only on nutrient utilization, but based on expected nutrient utilization within the environmental context expected in/on/around the target plant.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of nutrient utilization, wherein they differ in the utilization of nutrients available in the corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn. In some embodiments, the consortium comprises at least two microbial species that differ in terms of carbon source utilization, wherein they differ in the utilization of a simple or complex carbohydrate, organic acid, amino acid, or carboxylic acid. In some embodiments, the consortium comprises at least two microbial species that differ in terms of nirogen source utilization, wherein they differ in the utilization of an amino acid, amine, amide, or peptide available in the corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn. In some embodiments, the consortium comprises at least two microbial species that differ in terms of carbon source utilization, and wherein the different carbon source utilization is such that the at least two microbial species could co-exist non-competitively in a plant rhizosphere, surface plant tissue region, and/or endophytic plant tissue region. In some embodiments, the consortium comprises at least two microbial species that differ in terms of nitrogen source utilization, and wherein the different nitrogen source utilization is such that the at least two microbial species could co-exist non-competitively in a plant rhizosphere, surface plant tissue region, and/or endophytic plant tissue region. In some embodiments, the consortium comprises at least two microbial species that differ in terms of nutrient utilization, and wherein the different nutrient utilization is such that the at least two microbial species could co-exist non-competitively in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
In some embodiments, at least two microbes within the consortium differ in terms of nutrient utilization such that competition between them is less than it would be between two microbes with the same nutrient utilization profile. In some embodiments, while the two microbes may still compete for certain resources, there is enough non-overlap in their nutrient utilization that each microbe can survive and fix nitrogen in the presence of the other.
In some embodiments, the at least two microbes with differing nutrient utilization include strains of Klebsiella variicola and Kosakonia sacchari. In some embodiments, the Klebsiella variicola strain is a strain identified by ATCC deposit number PTA-126740, and the Kosakonia saccharhi strain is a strain identified by ATCC deposit number PTA-126743.
Nutrient availability also varies within, on, and around a given plant at different time periods of the plant's growing cycle. See
Nutrient utilization of a microbe may be measured according to known methods, e.g., metabolomics methods. See
In some embodiments, at least two microbes within the consortium differ in terms of spatial occupation. The plant rhizosphere can be separated into three unique geographies that interact with each other. The endorhizosphere is the portion of the rhizosphere that includes the plant cortex and endodermis. Microbes that can colonize this space are commonly referred to as plant endophytes and usually occupy the space between plant cells, also known as the apoplastic space. The rhizoplane refers to the middle part of the rhizosphere and includes the root surface, including root mucilage. Microbes that occupy this space are commonly referred to as being plant-associated. The third zone of the rhizosphere is the ectorhizosphere and this extends from the rhizoplane to the soil directly surrounding the plant root. These three planes of the rhizosphere are extremely fluid with a constant exchange of metabolites and gasses. These sections are not defined by hard boarders but rather, have various chemical, biological and physical gradients. Microbes can prefer to occupy one, two or all of these niches.
In some embodiments, the consortium comprises at least two microbes that differ in terms of spatial occupation of at least one of these zones. In some embodiments, the consortium comprises at least two microbes that differ in terms of spatial occupation of the endorhizosphere. In some embodiments, the consortium comprises at least two microbes that differ in terms of spatial occupation of the rhizoplane. In some embodiments, the consortium comprises at least two microbes that differ in terms of spatial occupation of the ectorhizosphere.
Each zone can be further subdivided into more spatial niches. For example, the rhizoplane comprises numerous sub-niches like root junctions (where most plant exudates are released), the zone of elongation (which is where the root extends and grows through the soil) and the root cap (the very end of the root strand). In some embodiments, the microbes may differ in terms of occupation of one or more spatial niches. In some embodiments, the consortium comprises at least two microbial species that differ in terms of spatial occupation of one or more of the root junctions, zone of elongation, root cap, root mucilage, root hairs, root surface, and plant stems of a given plant.
In some embodiments, the plurality of microbes of one species occupy one zone or niche that is different from the zone or niche occupied by the plurality of microbes of another species. In some embodiments, the two microbes overlap in spatial occupation, but each also occupies a zone or niche that the other doesn't occupy. In some embodiments, the two microbes overlap in spatial occupation, but at least one of the microbes also occupies a zone or niche that the other doesn't occupy.
In some embodiments, the present disclosure provides microbial consortia comprising derepressed diazotrophs that occupy different spatial niches on, within, or closely associated with a plant root, such that the microbes within the consortium experience less competition for resources from other members of the consortium. In some embodiments, through this diversification of spatial occupation within the consortium, the microbes are able to supply a more consistent feed of nitrogen to the plant versus a single strain or an assemblage of microbes that occupy the same spatial niche but do not differ along other dimensions disclosed herein.
The spatial localization of some microorganisms on some plants is known. For example, Haahtela et al. (Applied and Environmental Microbiology 1986; 52: 1074-1079) found that Klebsiella attach to root hairs, the surface of the zone of elongation and the root cap mucilage. Paenibacillus polymyxa has been found mainly on the root surface (Hao et al., PLoS ONE 2017; 12(1): e0169980). Elbeltagy et al. (Applied and Environmental Microbiology 2001; 67(11): 5285-5293) found Herbaspirillum strains can be endophytic. Garcia et al. (Plant and Soil 2019:1-18) has shown that Paraburkolderia sticks mostly to root surfaces but can also colonize plant stems. Each of the foregoing references is herein incorporated by reference in its entirety.
In some embodiments, the consortium comprises at least two microbes that differ in terms of temporal occupation of a plant, its surface, or its surrounding environment. In some embodiments, the microbes overlap in temporal occupation, but experience different time periods of peak activity. The activity may be nitrogen fixation, colony growth, nutrient consumption, or any other activity related to the growth of the microbial population.
In some embodiments, nitrogen fixation is the measure of interest. In some embodiments, the microbes differ in terms of when their period of peak nitrogen fixation occurs. In some embodiments, peak nitrogen fixation periods may differ by 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks, 11 weeks, or 12 weeks in the average plant growing cycle. In some embodiments, the peak nitrogen fixation period of the microbes may differ by at least two weeks. In some embodiments, peak nitrogen fixation periods may differ by 1 month, 2 months, 3 months, 4 months, 5 months, 6 months, 7 months, 8 months, 9 months, or 10 months in the average plant growing cycle. In some embodiments, the peak nitrogen fixation period of the microbes may differ by at least one month in the average plant growing cycle.
In some embodiments, colonization is the measure of interest. In some embodiments, the microbes differ in terms of when their period of peak colonization occurs. In some embodiments, peak colonization periods may differ by 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks, 11 weeks, or 12 weeks in the average plant growing cycle. In some embodiments, the peak colonization period of the microbes may differ by at least two weeks. In some embodiments, peak colonization periods may differ by 1 month, 2 months, 3 months, 4 months, 5 months, 6 months, 7 months, 8 months, 9 months, or 10 months in the average plant growing cycle. In some embodiments, the peak colonization period of the microbes may differ by at least one month in the average plant growing cycle.
In embodiments where the target plant is corn, the microbes may differ in the stage of the corn growing cycle during which they experience peak nitrogen fixation. In some embodiments, the peak nitrogen fixation period of the microbes differs by at least one stage. In some embodiments, the peak nitrogen fixation time periods of the at least two microbial species comprised by the consortium occurs during a different stage, or series of two or more stages, of the corn growing cycle selected from VE, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13, V14, V15, V16, VT, R1, R2, R3, R4, R5, and R6. In some embodiments, the peak nitrogen fixation time periods of the at least two microbial species occur during different periods of the corn growing cycle selected from V4-V6, V6-V10, and V10-V12.
In embodiments where the target plant is corn, the microbes may differ in the stage of the corn growing cycle during which they experience peak colonization. In some embodiments, the peak colonization period of the microbes differs by at least one stage. In some embodiments, the peak colonization time periods of the at least two microbial species comprised by the consortium occurs during a different stage, or series of two or more stages, of the corn growing cycle selected from VE, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13, V14, V15, V16, VT, R1, R2, R3, R4, R5, and R6. In some embodiments, the peak colonization time periods of the at least two microbial species occur during different periods of the corn growing cycle selected from V4-V6, V6-V10, and V10-V12.
In some embodiments, the temporal occupation of the microbes differs enough that the microbes could non-competitively fix nitrogen for a given plant at different time periods of the plant's growing cycle. In some embodiments, the temporal occupation of the microbes differs enough that the microbes could non-competitively colonize a given plant at different time periods of the plant's growing cycle. In some embodiments, the time periods of nitrogen fixation overlap, but are not identical. In some embodiments, the time periods of colonization overlap, but are not identical. In some embodiments, while the microbes may compete for resources during a given period of the growing cycle of a plant, there are periods of the growing cycle where one or the other or both do not compete.
In some embodiments, the consortium comprises at least two microbial species that differ in terms of oxygen adaptability. The oxygen adaptability of a given microbe may be measured by observing a variety of growth parameters under different oxygenation conditions, such as nutrient consumption, colony growth, ATP production, and nitrogen fixation. In some embodiments, the oxygen adaptability is measured by observing the nitrogen fixation ability of a microbe under different oxygenation conditions.
Oxygenation conditions can fall within the general categories of aerobic (high oxygenation), hypoxic (low oxygenation), microaerobic (very low oxygenation), and anaerobic (no oxygenation). Some microbes thrive in aerobic conditions, but not hypoxic or anaerobic conditions. Some microbes are the reverse. Certain microbes prefer microaerobic environments. Others are adaptable to all oxygenation conditions. In some embodiments, the consortium comprises at least two microbes that differ in terms of their suitability for different oxygenation conditions. In some embodiments, one of the microbes is suitable for high oxygenation conditions, while the other is suitable for low oxygenation conditions, or any such division of oxygenation conditions. In some embodiments, one of the microbes is adaptable to any of the conditions, while the other is restricted to a particular oxygenation condition. In some embodiments, the oxygenation adaptability of the microbes differs enough to limit competition for resources between the microbes at a given oxygenation condition.
In some embodiments, the disclosed microbial consortia may outperform a single microbe in supporting the nitrogen fixation needs of a given plant. In some embodiments, the microbial consortia may be able to provide some, most, or all of the nitrogen supply required for optimal growth of the plant. In some embodiments, the microbial consortia may reduce the reliance on other sources of nitrogenous fertilization, e.g., synthetic fertilizers. In some embodiments, the microbial consortia may eliminate the need for other sources of nitrogenous fertilization.
In the context of corn, the microbial consortium may be able to provide some, most, or all of the nitrogen supply required for optimal growth of corn. In some embodiments, the consortium delivers at least 40, at least 50, at least 60, at least 70, at least 80, at least 90, at least 100, at least 110, at least 120, at least 130, at least 140, at least 150, at least 160, at least 170, at least 180, at least 190, or at least 200 pounds of nitrogen per acre of corn comprising the consortium over the course of the corn growing cycle. In some embodiments, the consortium delivers at least 200 pounds of nitrogen per acre of corn comprising the consortium over the course of the corn growing cycle. In some embodiments, the composition delivers approximately 1.5-3.0 pounds of nitrogen per day per acre of corn comprising the composition between days 30-50 of the average corn growing cycle. In some embodiments, wherein the composition delivers approximately 0.5-3.0 pounds of nitrogen per day per acre of corn comprising the composition between days 55-75 of the average corn growing cycle.
The following examples are given for the purpose of illustrating various embodiments of the disclosure and are not meant to limit the present disclosure in any fashion. Changes therein and other uses which are encompassed within the spirit of the disclosure, as defined by the scope of the claims, will be recognized by those skilled in the art.
An example overview of an embodiment of the Guided Microbial Remodeling (GMR) platform can be summarized in the schematic of
The metabolism of the species of interest can be mapped and linked to genetics. For example, the nitrogen fixation pathway of the microbe can be characterized. The pathway that is being characterized can be examined under a range of environmental conditions. For example, the microbe's ability to fix atmospheric nitrogen in the presence of various levels of exogenous nitrogen in its environment can be examined. The metabolism of nitrogen can involve the entrance of ammonia (NH4+) from the rhizosphere into the cytosol of the bacteria via the AmtB transporter. Ammonia and L-glutamate (L-Glu) are catalyzed by glutamine synthetase and ATP into glutamine. Glutamine can lead to the formation of bacterial biomass and it can also inhibit expression of the nif operon, i.e. it can be a competing force when one desires the microbe to fix atmospheric nitrogen and excrete ammonia. The nitrogen fixation pathway is characterized in great detail in earlier sections of the specification.
Afterwards, a targeted non-intergeneric genomic alteration can be introduced to the microbe's genome, using methods including, but not limited to: conjugation and recombination, chemical mutagenesis, adaptive evolution, and gene editing. The targeted non-intergeneric genomic alteration can include an insertion, disruption, deletion, alteration, perturbation, modification, etc. of the genome.
Derivative remodeled microbes, which comprise the desired phenotype resulting from the remodeled underlying genotype, are then used to inoculate crops.
The present disclosure provides, in certain embodiments, non-intergeneric remodeled microbes that are able to fix atmospheric nitrogen and supply such nitrogen to a plant. In aspects, these non-intergeneric remodeled microbes are able to fix atmospheric nitrogen, even in the presence of exogenous nitrogen.
The aforementioned Guided Microbial Remodeling (GMR) platform will now be described with more specificity.
In aspects, the GMR platform comprises the following steps:
A. Isolation—Obtain microbes from the soil, rhizosphere, surface, etc. of a crop plant of interest;
B. Characterization—Involves characterizing the isolated microbes for genotype/phenotypes of interest (e.g. genome sequence, colonization ability, nitrogen fixation activity, solubilization of P ability, excretion of a metabolite of interest, excretion of a plant promoting compound, etc.)
C. Domestication—Development of a molecular protocol for non-intergeneric genetic modification of the microbe;
D. Non-Intergeneric Engineering Campaign and Optimization—Generation of derivative non-intergeneric microbial strains with genetic modifications in key pathways (e.g. colonization associated genes, nitrogen fixation/assimilation genes, P solubilization genes);
E. Analytics—Evaluation of derived non-intergeneric strains for phenotypes of interest both in vitro (e.g. ARA assays) and in planta (e.g. colonization assays).
F. Iterate Engineering Campaign/Analytics—Iteration of steps D and E for further improvement of microbial strain.
Each of the GMR platform process steps will now be elaborated upon below.
A. Isolation of Microbes
1. Obtain a Soil Sample
Microbes will be isolated from soil and/or roots of a plant. In one example, plants will be grown in a laboratory or a greenhouse in small pots. Soil samples will be obtained from various agricultural areas. For example, soils with diverse texture characteristics can be collected, including loam (e.g. peaty clay loam, sandy loam), clay soil (e.g. heavy clay, silty clay), sandy soil, silty soil, peaty soil, chalky soil, and the like.
2. Grow Bait Plants
Seeds of a bait plant (a plant of interest) (e.g. corn, wheat, rice, sorghum, millet, soybean, vegetables, fruits, etc.) will be planted into each soil type. In one example, different varieties of a bait plant will be planted in various soil types. For example, if the plant of interest is corn, seeds of different varieties of corn such as field corn, sweet corn, heritage corn, etc. will be planted in various soil types described above.
3. Harvest Soil and/or Root Samples and Plate on Appropriate Medium
Plants will be harvested by uprooting them after a few weeks (e.g. 2-4 weeks) of growth. Alternative to growing plants in a laboratory/greenhouse, soil and/or roots of the plant of interest can be collected directly from the fields with different soil types.
To isolate rhizosphere microbes and epiphytes, plants will be removed gently by saturating the soil with distilled water or gently loosening the soil by hand to avoid damage to the roots. If larger soil particles are present, these particles will be removed by submerging the roots in a still pool of distilled water and/or by gently shaking the roots. The root will be cut and a slurry of the soil sticking to the root will be prepared by placing the root in a plate or tube with small amount of distilled water and gently shaking the plate/tube on a shaker or centrifuging the tube at low speed. This slurry will be processed as described below.
To isolate endophytes, excess soil on root surfaces will be removed with deionized water. Following soil removal, plants will be surface sterilized and rinsed vigorously in sterile water. A cleaned, 1 cm section of root will be excised from the plant and placed in a phosphate buffered saline solution containing 3 mm steel beads. A slurry will be generated by vigorous shaking of the solution with a Qiagen TissueLyser II.
The soil and/or root slurry can be processed in various ways depending on the desired plant-beneficial trait of microbes to be isolated. For example, the soil and root slurry can be diluted and inoculated onto various types of screening media to isolate rhizospheric, endophytic, epiphytic, and other plant-associated microbes. For example, if the desired plant-beneficial trait is nitrogen fixation, then the soil/root slurry will be plated on a nitrogen free media (e.g. Nfb agar media) to isolate nitrogen fixing microbes. Similarly, to isolate phosphate solubilizing bacteria (PSB), media containing calcium phosphate as the sole source of phosphorus can be used. PSB can solubilize calcium phosphate and assimilate and release phosphorus in higher amounts. This reaction is manifested as a halo or a clear zone on the plate and can be used as an initial step for isolating PSB.
4. Pick Colonies, Purify Cultures, and Screen for the Presence of Genes of Interest
Populations of microbes obtained in step A3 are streaked to obtain single colonies (pure cultures). A part of the pure culture is resuspended in a suitable medium (e.g. a mixture of R2A and glycerol) and subjected to PCR analysis to screen for the presence of one or more genes of interest. For example, to identify nitrogen fixing bacteria (diazotrophs), purified cultures of isolated microbes can be subjected to a PCR analysis to detect the presence of nif genes that encode enzymes involved in the fixation of atmospheric nitrogen into a form of nitrogen available to living organisms.
5. Bank a Purified Culture
Purified cultures of isolated strains will be stored, for example at −80° C., for future reference and analysis.
B. Characterization of Isolated Microbes
1. Phylogenetic Characterization and Whole Genome Sequencing
Isolated microbes will be analyzed for phylogenetic characterization (assignment of genus and species) and the whole genome of the microbes will be sequenced.
For phylogenetic characterization, 16S rDNA of the isolated microbe will be sequenced using degenerate 16S rDNA primers to generate phylogenetic identity. The 16S rDNA sequence reads will be mapped to a database to initially assign the genus, species and strain name for isolated microbes. Whole genome sequencing is used as the final step to assign phylogenetic genus/species to the microbes.
The whole genome of the isolated microbes will be sequenced to identify key pathways. For the whole genome sequencing, the genomic DNA will be isolated using a genomic DNA isolation kit (e.g. QIAmp DNA mini kit from QIAGEN) and a total DNA library will be prepared using the methods known in the art. The whole genome will be sequenced using high throughput sequencing (also called Next Generation Sequencing) methods known in the art. For example, Illumina, Inc., Roche, and Pacific Biosciences provide whole genome sequencing tools that can be used to prepare total DNA libraries and perform whole genome sequencing.
The whole genome sequence for each isolated strain will be assembled; genes of interest will be identified; annotated; and noted as potential targets for remodeling. The whole genome sequences will be stored in a database.
2. Assay the Microbe for Colonization of a Host Plant in a Greenhouse
Isolated microbes will be characterized for the colonization of host plants in a greenhouse. For this, seeds of the desired host plant (e.g., corn, wheat, rice, sorghum, soybean) will be inoculated with cultures of isolated microbes individually or in combination and planted into soil. Alternatively, cultures of isolated microbes, individually or in combination, can be applied to the roots of the host plant by inoculating the soil directly over the roots. The colonization potential of the microbes will be assayed, for example, using a quantitative PCR (qPCR) method described in a greater detail below.
3. Assay the Microbe for Colonization of the Host Plant in Small-Scale Field Trials and Isolate RNA from Colonized Root Samples (CAT Trials)
Isolated microbes will be assessed for colonization of the desired host plant in small-scale field trials. Additionally, RNA will be isolated from colonized root samples to obtain transcriptome data for the strain in a field environment. These small-scale field trials are referred to herein as CAT (Colonization and Transcript) trials, as these trials provide Colonization and Transcript data for the strain in a field environment.
For these trials, seeds of the host plant (e.g., corn, wheat, rice, sorghum, soybean) will be inoculated using cultures of isolated microbes individually or in combination and planted into soil. Alternatively, cultures of isolated microbes, individually or in combination, can be applied to the roots of the host plant by inoculating the soil directly over the roots. The CAT trials can be conducted in a variety of soils and/or under various temperature and/or moisture conditions to assess the colonization potential and obtain transcriptome profile of the microbe in various soil types and environmental conditions.
Colonization of roots of the host plant by the inoculated microbe(s) will be assessed, for example, using a qPCR method as described below.
In one protocol, the colonization potential of isolated microbes was assessed as follows. One day after planting of corn seeds, 1 ml of microbial overnight culture (SOB media) was drenched right at the spot of where the seed was located. 1 mL of this overnight culture was roughly equivalent to about 10{circumflex over ( )}9 cfu, varying within 3-fold of each other, depending on which strain is being used. Each seedling was fertilized 3× weekly with 50 mL modified Hoagland's solution supplemented with either 2.5 mM or 0.25 mM ammonium nitrate. At four weeks after planting, root samples were collected for DNA extraction. Soil debris were washed away using pressurized water spray. These tissue samples were then homogenized using QIAGEN Tissuelyzer and the DNA was then extracted using QIAmp DNA Mini Kit (QIAGEN) according to the recommended protocol. qPCR assay was performed using Stratagene Mx3005P RT-PCR on these DNA extracts using primers that were designed (using NCBI's Primer BLAST) to be specific to a loci in each of the microbe's genome.
The presence of the genome copies of the microbe was quantified, which reflected the colonization potential of the microbe. Identity of the microbial species was confirmed by sequencing the PCR amplification products.
Additionally, RNA will be isolated from colonized root and/or soil samples and sequenced.
Unlike the DNA profile, an RNA profile varies depending on the environmental conditions. Therefore, sequencing of RNA isolated from colonized roots and/or soil will reflect the transcriptional activity of genes in planta in the rhizosphere.
RNA can be isolated from colonized root and/or soil samples at different time points to analyze the changes in the RNA profile of the colonized microbe at these time points.
For example, RNA can be isolated from colonized root and/or soil samples right after fertilization of the field and a few weeks after fertilization of the field and sequenced to generate corresponding transcriptional profile.
Similarly, RNA sequencing can be carried out under high phosphate and low phosphate conditions to understand which genes are transcriptionally active or repressed under these conditions.
Methods for transcriptomic/RNA sequencing are known in the art. Briefly, total RNA will be isolated from the purified culture of the isolated microbe; cDNA will be prepared using reverse transcriptase; and the cDNA will be sequenced using high throughput sequencing tools described above.
Sequencing reads from the transcriptome analysis can be mapped to the genomic sequence and transcriptional promoters for the genes of interest can be identified.
4. Assay the Plant-Beneficial Activity of Isolated Microbes
The plant-beneficial activity of isolated microbes will be assessed.
For example, nitrogen fixing microbes will be assayed for nitrogen fixation activity using an acetylene reduction assay (ARA) or phosphate solubilizing microbes will be assayed for phosphate solubilization. Any parameter of interest can be utilized and an appropriate assay developed for such. For instance, assays could include growth curves for colonization metrics and assays for production of phytohormones like indole acetic acid (IAA) or gibberellins. An assay for any plant-beneficial activity that is of interest can be developed.
This step will confirm the phenotype of interest and eliminate any false positives.
5. Selection of Potential Candidates from Isolated Microbes
The data generated in the above steps will be used to select microbes for further development. For example, microbes showing a desired combination of colonization potential, plant-beneficial activity, and/or relevant DNA and RNA profile will be selected for domestication and remodeling.
C. Domestication of Selected Microbes
The selected microbes will be domesticated; wherein, the microbes will be converted to a form that is genetically tractable and identifiable.
1. Test for Antibiotic Sensitivity
One way to domesticate the microbes is to engineer them with antibiotic resistance. For this, the wild type microbial strain will be tested for sensitivity to various antibiotics. If the strain is sensitive to the antibiotic, then the antibiotic can be a good candidate for use in genetic tools/vectors for remodeling the strain.
2. Design and Build a Vector
Vectors that are conditional for their replication (e.g. a suicide plasmid) will be constructed to domesticate the selected microbes (host microbes). For example, a suicide plasmid containing an appropriate antibiotic resistance marker, a counter selectable marker, an origin of replication for maintenance in a donor microbe (e.g. E. coli), a gene encoding a fluorescent protein (GFP, RFP, YFP, CFP, and the like) to screen for insertion through fluorescence, an origin of transfer for conjugation into the host microbe, and a polynucleotide sequence comprising homology arms to the host genome with a desired genetic variation will be constructed. The vector may comprise a SceI site and other additional elements.
Exemplary antibiotic resistance markers include ampicillin resistance marker, kanamycin resistance marker, tetracycline resistance marker, chloramphenicol resistance marker, erythromycin resistance marker, streptomycin resistance marker, spectinomycin resistance marker, etc. Exemplary counter selectable markers include sacB, rpsL, tetAR, pheS, thyA, lacY, gata-1, ccdB, etc.
3. Generation of Donor Microbes
In one protocol, a suicide plasmid containing an appropriate antibiotic resistance marker, a counter selectable marker, the λpir origin of replication for maintenance in E. coli ST18 containing the pir replication initiator gene, a gene encoding green fluorescent protein (GFP) to screen for insertion through fluorescence, an origin of transfer for conjugation into the host microbe, and a polynucleotide sequence comprising homology arms to the host genome with a desired genetic variation (e.g. a promoter from within the microbe's own genome for insertion into a heterologous location) will be transformed into E. coli ST18 (an auxotroph for aminolevulinic acid, ALA) to generate donor microbes.
4. Mix Donor Microbes with Host Microbes
Donor microbes will be mixed with host microbes (selected candidate microbes from step B5) to allow conjugative integration of the plasmid into the host genome. The mixture of donor and host microbes will be plated on a medium containing the antibiotic and not containing ALA. The suicide plasmid is able to replicate in donor microbes (E. coli ST18), but not in the host. Therefore, when the mixture containing donor and host microbes is plated on a medium containing the antibiotic and not containing ALA, only host cells that integrated the plasmid into its genome will be able to grow and form colonies on the medium. The donor microbes will not grow due to the absence of ALA.
5. Confirm Integration of the Vector
A proper integration of the suicide plasmid containing the fluorescent protein marker, the antibiotic resistance marker, the counter selectable marker, etc. at the intended locus of the host microbe will be confirmed through fluorescence of colonies on the plate and using colony PCR.
6. Streak Confirm Integration Colony
A second round of homologous recombination in the host microbes will loop out (remove) the plasmid backbone leaving the desired genetic variation (e.g. a promoter from within the microbe's own genome for insertion into a heterologous location) integrated into the host genome of a certain percentage of host microbes, while reverting a certain percentage back to wild type.
Colonies of host microbes that have looped out the plasmid backbone (and therefore, looped out the counter selectable marker) can be selected by growing them on an appropriate medium.
For example, if sacB is used as a counter selectable marker, loss of this marker due to the loss of the plasmid backbone will be tested by growing the colonies on a medium containing sucrose (sacB confers sensitivity to sucrose). Colonies that grow on this medium would have lost the sacB marker and the plasmid backbone and would either contain the desired genetic variation or be reverted to wild type. Also, these colonies will not fluoresce on the plate due to the loss of the fluorescent protein marker.
In some isolates, the sacB or other counterselectable markers do not confer full sensitivity to sucrose or other counterselection mechanisms, which necessitates screening large numbers of colonies to isolate a successful loop-out. In those cases, loop-out may be aided by use of a “helper plasmid” that replicates independently in the host cell and expresses a restriction endonuclease, e.g. SceI, which recognizes a site in the integrated suicide plasmid backbone. The strain with the integrated suicide plasmid is transformed with the helper plasmid containing an antibiotic resistance marker, an origin of replication compatible with the host strain, and a gene encoding a restriction endonuclease controlled by a constitutive or inducible promoter. The double-strand break induced in the integrated plasmid backbone by the restriction endonuclease promotes homologous recombination to loop-out the suicide plasmid. This increases the number of looped-out colonies on the counterselection plate and decreases the number of colonies that need to be screened to find a colony containing the desired mutation. The helper plasmid is then removed from the strain by culture and serial passaging in the absence of antibiotic selection for the plasmid. The passaged cultures are streaked for single colonies, colonies are picked and screened for sensitivity to the antibiotic used for selection of the helper plasmid, as well as absence of the plasmid confirmed by colony PCR. Finally, the genome is sequenced and the absence of helper plasmid DNA is confirmed as described in D6.
7. Confirm Integration of the Genetic Variation Through Colony PCR
The colonies that grew better on the sucrose-containing medium (or other appropriate media depending on the counter selectable marked used) will be picked and the presence of the genetic variation at the intended locus will be confirmed by screening the colonies using colony PCR.
Although this example describes one protocol for domesticating the microbe and introducing genetic variation into the microbe, one of ordinary skill in the art would understand that the genetic variation can be introduced into the selected microbes using a variety of other techniques known in the art such as: polymerase chain reaction mutagenesis, oligonucleotide-directed mutagenesis, saturation mutagenesis, fragment shuffling mutagenesis, homologous recombination, ZFN, TALENS, CRISPR systems (Cas9, Cpfl, etc.), chemical mutagenesis, and combinations thereof.
8. Iterate Upon Steps C2-C7
If any of the steps C2-C7 fail to provide the intended outcome, the steps will be repeated to design an alternative vector that may comprise different elements for facilitating incorporation of desired genetic variations and markers into the host microbe.
9. Develop a Standard Operating Procedure (SOP)
Once the steps C2-C7 can be reproduced consistently for a given strain, the steps will be used to develop a standard operating procedure (SOP) for that strain and vector. This SOP can be used to improve other plant-beneficial traits of the microbe.
D. Non-Intergeneric Engineering Campaign and Optimization
1. Identify Gene Targets for Optimization
Selected microbes will be engineered/remodeled to improve performance of the plant-beneficial activity. For this, gene targets for improving the plant-beneficial activity will be identified.
Gene targets can be identified in various ways. For example, genes of interest can be identified while annotating the genes from the whole genome sequencing of isolated microbes. They can be identified through a literature search. For example, genes involved in nitrogen fixation are known in the literature. These known genes can be used as targets for introducing genetic variations. Gene targets can also be identified based on the RNA sequencing data obtained in the step B3 (small-scale field trials for colonization) or by performing RNA sequencing described in the step below.
2. Select Promoters for Promoter Swaps
A desired genetic variation for improving the plant-beneficial activity can comprise promoter swapping, in which the native promoter for a target gene is replaced with a stronger or weaker promoter (when compared to the native promoter) from within the microbe's genome, or differently regulated promoter (e.g. a N-independent). If the expression of a target gene increases the plant-beneficial activity (e.g., nifA, the expression of which enhances nitrogen fixation in microbes), the desired promoter for promoter swapping is a stronger promoter (compared to the native promoter of the target gene) that would further increase the expression level of the target gene compared to the native promoter. If the expression of a target gene decreases the plant-beneficial activity (e.g., nifL that downregulates nitrogen fixation), the desired promoter for promoter swapping is a weak promoter (compared to the native promoter of the target gene) that would substantially decrease the expression level of the target gene compared to the native promoter. Promoters can be inserted into genes to “knock-out” a gene's expression, while at the same time upregulating the expression of a downstream gene.
Promoters for promoter swapping can be selected based on the RNA sequencing data. For example, the RNA sequencing data can be used to identify strong and weak promoters, or constitutively active vs. inducible promoters.
For example, to identify strong and weak promoters, or constitutively active vs. inducible promoters, in the nitrogen fixation pathway, selected microbes will be cultured in vitro under nitrogen-depleted and nitrogen-replete conditions; RNA of the microbe will be isolated from these cultures; and sequenced.
In one protocol, the RNA profile of the microbe under nitrogen-depleted and nitrogen-replete conditions will be compared and active promoters with a desired transcription level will be identified. These promoters can be selected to swap a weak promoter.
Promoters can also be selected using the RNA sequencing data obtained in the step B3 that reflects the RNA profile of the microbe in planta in the host plant rhizosphere.
RNA sequencing under various conditions allows for selection of promoters that: a) are active in the rhizosphere during the host plant growth cycle in fertilized field conditions, and b) are also active in relevant in vitro conditions so they can be rapidly screened.
In an exemplary protocol, in planta RNA sequencing data from colonization assays (e.g. step B3) is used to measure the expression levels of genes in isolated microbes. In one embodiment, the level of gene expression is calculated as reads per kilobase per million mapped reads (RPKM). The expression level of various genes is compared to the expression level of a target gene and at least the top 10, 20, 30, 40, 50, 60, or 70 promoters, associated with the various genes, that show the highest or lowest level of expression compared to the target gene are selected as possible candidates for promoter swapping. Thus, one looks at expression levels of various genes relative to a target gene and then selects genes that demonstrate increased expression relative to a target (or standard) gene and then find the promoters associated with said genes.
For example, if the target gene is upregulation of nifA, the first 10, 20, 30, 40, 50, or 60 promoters for genes that show the highest level of expression compared to nifA are selected as possible candidates for promoter swapping.
These candidates can be further short-listed based on in vitro RNA sequencing data. For example, for nifA as the target gene, possible promoter candidates selected based on the in planta RNA sequencing data are further selected by choosing promoters with similar or increased gene expression levels compared to nifA under in vitro nitrogen-deplete vs. nitrogen-replete conditions.
The set of promoters selected in this step are used to swap the native promoter of the target gene (e.g. nifA). Remodeled strains with swapped promoters are tested in in vitro assays; strains with lower than expected activity are eliminated; and strains with expected or higher than expected activity are tested in field. The cycle of promoter selection may be repeated on remodeled strains to further improve their plant-beneficial activity.
Described here is an exemplary promoter swap experiment that was carried out based on in planta and in vitro RNA sequencing data from Klebsiella variicola strain, CI137 to improve the nitrogen fixation trait. CI137 was analyzed in ARA assays at 0 mM and 5 mM glutamine concentration and RNA was extracted from these ARA samples. The RNA was sequenced via NextSeq and a subset of reads from one sample was mapped to the CI137 genome (in vitro RNA sequencing data). RNA was extracted from the roots of corn plants at V5 stage in the colonization and activity assay (e.g. step B3) for CI137. Samples from 6 plants were pooled; the RNA from the pooled sample was sequenced using NextSeq, and reads were mapped to the CI137 genome (in planta RNA sequencing data). Out of 2×108 total reads, 7×104 reads mapped to CI137. In planta RNA sequencing data was used to rank genes in order of in planta expression levels and the expression levels were compared to the native nifA expression level. The first 40 promoters that showed the highest expression level (based on gene expression) compared to the native nifA expression level were selected. These 40 promoters were further short-listed based on the in vitro RNA sequencing data, where promoters with increased or similar in vitro expression levels compared to nifA were selected. The final list of promoters included 17 promoters and 2 versions of most promoters were used to generate promoter swap mutants; thus a total of 30 promoters were tested. Generation of a suite of CI137 mutants where nifL was deleted partially or completely and the 30 promoters inserted (ΔnifL::Prm) was attempted. 28 out of 30 mutants were generated successfully. The ΔnifL::Prm mutants were analyzed in ARA assays at 0 mM and 5 mM glutamine concentration and RNA was extracted from these ARA samples. Several mutants showed lower than expected or decreased ARA activity compared to the WT CI137 strain. A few mutants showed higher than expected ARA activity.
A person of ordinary skill in the art would appreciate from the above example that while in planta and/or in vitro RNA sequencing data can be used to select promoters for promoter swapping, the step of promoter selection is highly unpredictable and involves many challenges.
For example, in planta RNA sequencing mainly reveals the genes that are highly expressed; however, it is difficult to detect fine differences in gene expression and/or genes with low expression levels. For instance, in some in planta RNA sequencing experiments, only about 40 out of about 5000 genes from a microbial genome were detected. Thus, in planta RNA sequencing technique is useful to identify abundantly expressed genes and their corresponding promoters; however, the technique has difficulty in identifying low expression genes and corresponding promoters and small differences between gene expression.
Furthermore, in planta RNA profile reflects the status of the genes at the time the microbes were isolated; however, a slight change in the field conditions can substantially change the RNA profile of rhizosphere/epiphytic/endophytic microbes. Therefore, it is difficult to predict in advance whether the promoters selected based on one field trial RNA sequencing data would provide desirable expression levels of the target gene when remodeled strains are tested in vitro and in field.
Additionally, in planta evaluation is time and resource-consuming; therefore, in planta experiments cannot be conducted often and/or repeated quickly or easily. On the other hand, while in vitro RNA sequencing can be conducted relatively quickly and easily, the in vitro conditions do not mimic the field conditions and promoters that may show high activity in vitro may not show comparable activity in planta.
Moreover, promoters often don't behave as predicted in a new context. Therefore, in planta and in vitro RNA sequencing data can at best serve as a starting point in the step of promoter selection; however, arriving at any particular promoter that would provide desirable expression levels of the target gene in the field is, in some instances, unpredictable.
Another limitation in the step of promoter selection is the number of available promoters. Because one of the goals of the present invention is to provide non-transgenic microbes; promoters for promoter swapping need to be selected from within the microbe's genome, or genus. Thus, unlike a transgenic approach, the present process can not merely go out into the literature and find/use a well characterized transgenic promoter from a different host organism.
Another constraint is that the promoter must be active in planta during a desired growth phase. For example, the highest requirement for nitrogen in plants is generally late in the growing season, e.g. late vegetative and early reproductive phases. For example, in corn, nitrogen uptake is the highest during V6 (6 leaves) through R1 (reproductive stage 1) stages. Therefore, to increase the availability of nitrogen during V6 through R1 stages of corn, remodeled microbes must show highest nitrogen fixation activity during these stages of the corn lifecycle. Accordingly, promoters that are active in planta during the late vegetative and early reproductive stages of corn need to be selected. This constraint not only reduces the number of promoters that may be tested in promoter swapping, but also make the step of promoter selection unpredictable. As discussed above, unpredictability arises, in part, because although the RNA sequencing data from small scale field trials (e.g. step B3) may be used to identify promoters that are active in planta during a desired growth stage, the RNA data is based on the field conditions (e.g., type of soil, level of water in the soil, level of available nitrogen, etc.) at the time of sample collection. As one of ordinary skill in the art would understand, the field conditions may change over the period of time within the same field and also change substantially across various fields. Thus, the promoters selected under one field condition may not behave as expected under other field conditions. Similarly, selected promoters may not behave as expected after swapping. Therefore, it is difficult to anticipate in advance whether the selected promoters would be active in planta during a desired growth phase of a plant of interest.
3. Design Non-Intergeneric Genetic Variations
Based on steps D1 (identification of gene targets) and D2 (identification of promoters for promoter swaps), non-intergeneric genetic variations will be designed.
The term “non-intergeneric” indicates that the genetic variation to be introduced into the host does not contain a nucleic acid sequence from outside the host genus (i.e., no transgenic DNA). Although vectors and/or other genetic tools will be used to introduce the genetic variation into the host microbe, the methods of the present disclosure include steps to loop-out (remove) the backbone vector sequences or other genetic tools introduced into the host microbe leaving only the desired genetic variation into the host genome. Thus, the resulting microbe is non-transgenic.
Exemplary non-intergeneric genetic variations include a mutation in the gene of interest that may improve the function of the protein encoded by the gene; a constitutionally active promoter that can replace the endogenous promoter of the gene of interest to increase the expression of the gene; a mutation that will inactivate the gene of interest; the insertion of a promoter from within the host's genome into a heterologous location, e.g. insertion of the promoter into a gene that results in inactivation of said gene and upregulation of a downstream gene; and the like. The mutations can be point mutations, insertions, and/or deletions (full or partial deletion of the gene). For example, in one protocol, to improve the nitrogen fixation activity of the host microbe, a desired genetic variation may comprise an inactivating mutation of the nifL gene (negative regulator of nitrogen fixation pathway) and/or comprise replacing the endogenous promoter of the nifH gene (nitrogenase iron protein that catalyzes a key reaction to fix atmospheric nitrogen) with a constitutionally active promoter that will drive the expression of the nifH gene constitutively.
4. Generate Non-Intergeneric Derivative Strains
After designing the non-intergeneric genetic variations, steps C2-C7 will be carried out to generate non-intergeneric derivative strains (i.e. remodeled microbes).
5. Bank a Purified Culture of the Remodeled Microbe
A purified culture of the remodeled microbe will be preserved in a bank, so that gDNA can be extracted for whole genome sequencing described below.
6. Confirm Presence of the Desired Genetic Variation
The genomic DNA of the remodeled microbe will be extracted and the whole genome sequencing will be performed on the genomic DNA using methods described previously. The resulting reads will be mapped to the reads previously stored in LIMS to confirm: a) presence of the desired genetic variation, and b) complete absence of reads mapping to vector sequences (e.g. plasmid backbone or helper plasmid sequence) that were used to generate the remodeled microbe.
This step allows sensitive detection of non-host genus DNA (transgenic DNA) that may remain in the strain after looping out of the vector backbone (e.g. suicide plasmid) method and could provide a control for accidental off-target insertion of the genetic variation, etc.
E. Analytics Upon Remodeled Microbes
1. Analysis of the Plant-Beneficial Activity
The plant-beneficial activity and growth kinetics of the remodeled microbes will be assessed in vitro.
For example, strains remodeled for improving nitrogen fixation function will be assessed for nitrogen fixation activity and fitness through acetylene reduction assays, ammonium excretion assays, etc.
Strains remodeled for improved phosphate solubilization will be assessed for the phosphate solubilization activity.
This step allows rapid, medium to high throughput screening of remodeled strains for the phenotypes of interest.
2. Analysis of Colonization and Transcription of the Altered Genes
Remodeled strains will be assessed for colonization of the host plant either in the greenhouse or in the field using the steps described in B3. Additionally, RNA will be isolated from colonized root and/or soil samples and sequenced to analyze the transcriptional activity of target genes. Target genes comprise the genes containing the genetic variation introduced and may also comprise other genes that play a role in the plant-beneficial trait of the microbe.
For example, a cluster of genes, the nif genes, controls the nitrogen fixation activity of microbes. Using the protocol described above, a genetic variation may be introduced into one of the nif genes (e.g. a promoter insertion), whereas the other genes in the nif cluster are in their endogenous form (i.e. their gene sequence and/or the promoter region is not altered). The RNA sequencing data will be analyzed for the transcriptional activity of the nif gene containing the genetic variation and may also be analyzed for other nif genes that are not altered directly, by the inserted genetic change, but nonetheless may be influenced by the introduced genetic change.
This step allows determination of the fitness of top in vitro performing strains in the rhizosphere and allows measurement of the transcriptional activity of altered genes in planta.
F. Iterate Engineering Campaign/Analytics
The data from in vitro and in planta analytics (steps E1 and E2) will be used to iteratively stack beneficial mutations.
Furthermore, steps A-E described above may be repeated to fine tune the plant-beneficial traits of the microbes. For example, plants will be inoculated using microbial strains remodeled in the first round; harvested after a few weeks of growth; and microbes from the soil and/or roots of the plants will be isolated. The functional activity (plant-beneficial trait and colonization potential) and the DNA and RNA profile of isolated microbes will be characterized, in order to select microbes with improved plant-beneficial activity and colonization potential. The selected microbes will be remodeled to further improve the plant-beneficial activity. Remodeled microbes will be screened for the functional activity (plant-beneficial trait and colonization potential) and RNA profile in vitro and in planta and the top performing strains will be selected. If desired, steps A-E can be repeated to further improve the plant-beneficial activity of the remodeled microbes from the second round. The process can be repeated for 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more rounds.
The exemplary steps described above are summarized in Table A below.
E. coli. GFP to
coli or other
E. coli but not in the
E. coli or other
Traditional Approaches to Creating Biologicals for Agriculture Suffer From Drawbacks Inherent in their Methodology
Unlike pure bioprospecting of wild-type (WT) microbes or transgenic approaches, GMR allows for non-intergeneric genetic optimization of key regulatory networks within the microbe, which improves plant-beneficial phenotypes over WT microbes, but doesn't have the risks associated with transgenic approaches (e.g. unpredictable gene function, public concerns). See,
Other methods for developing microbials for agriculture are focused on either extensive lab development, which often fails at the field scale, or extensive greenhouse or “field-first” testing without an understanding of the underlying mechanisms/plant-microbe interactions. See,
The GMR Platform Solves These Problems in Numerous Ways
One strength of the GMR platform is the identification of active promoters, which are active at key physiologically important times for a target crop, and which are also active under particular, agriculturally relevant, environmental conditions.
As has been explained, within the context of nitrogen fixation, the GMR platform is able to identify microbial promoter sequences, which are active under environmental conditions of elevated exogenous nitrogen, which thereby allows the remodeled microbe to fix atmospheric nitrogen and deliver it to a target crop plant, under modern agricultural row crop conditions, and at a time when a plant needs the fixed nitrogen the most. See,
These promoters can be identified by rhizosphere RNA sequencing and read mapping to the microbe's genome sequence, and key pathways can be “reprogrammed” to be turned on or off during key stages of the plant growth cycle. Additionally, through whole genome sequencing of optimized microbes and mapping to previously-transformed sequences, the method has the ability to ensure that no transgenic sequences are accidentally released into the field through off-target insertion of plasmid DNA, low-level retention of plasmids not detected through PCR or antibiotic resistance, etc.
The GMR platform combines these approaches by evaluating microbes iteratively in the lab and plant environment, leading to microbes that are robust in greenhouse and field conditions rather than just in lab conditions.
Various aspects and embodiments of the taught GMR platform can be found in
The traditional bioprospecting methods are not able to produce microbes having the aforementioned properties.
Properties of a Microbe Remodeled for Nitrogen Fixation
In the context of remodeling microbes for nitrogen fixation, there are several properties that the remodeled microbe may possess. For instance,
Furthermore, as can be seen in Example 2, the present inventors have utilized the GMR platform to produce remodeled non-intergeneric bacteria (i.e. Kosakonia sacchari) capable of fixing atmospheric nitrogen and delivering said nitrogen to a corn plant, even under conditions in which exogenous nitrogen is present in the environment. See,
These remodeled microbes ultimately result in corn yield improvement, when applied to corn crops. See,
The GMR Platform Provides an Approach to Nitrogen Fixation and Delivery That Solves Pressing Environmental Concerns
As explained previously, the nitrogen fertilizer produced by the industrial Haber-Bosch process is not well utilized by the target crop. Rain, runoff, heat, volatilization, and the soil microbiome degrade the applied chemical fertilizer. This equates to not only wasted money, but also adds to increased pollution instead of harvested yield. To this end, the United Nations has calculated that nearly 80% of fertilizer is lost before a crop can utilize it. Consequently, modern agricultural fertilizer production and delivery is not only deleterious to the environment, but it is extremely inefficient. See,
The current GMR platform, and resulting remodeled microbes, provide a better approach to nitrogen fixation and delivery to plants. As will be seen in the below Examples, the non-intergeneric remodeled microbes of the disclosure are able to colonize the roots of a corn plant and spoon feed said corn plants with fixed atmospheric nitrogen, even in the presence of exogenous nitrogen. This system of nitrogen fixation and delivery—enabled by the taught GMR platform—will help transform modern agricultural to a more environmentally sustainable system.
A diversity of nitrogen fixing bacteria can be found in nature, including in agricultural soils. However, the potential of a microbe to provide sufficient nitrogen to crops to allow decreased fertilizer use may be limited by repression of nitrogenase genes in fertilized soils as well as low abundance in close association with crop roots. Identification, isolation and breeding of microbes that closely associate with key commercial crops might disrupt and improve the regulatory networks linking nitrogen sensing and nitrogen fixation and unlock significant nitrogen contributions by crop-associated microbes. To this end, nitrogen fixing microbes that associate with and colonize the root system of corn were identified. This step corresponds to the “Measure the Microbiome Composition” depicted in
Root samples from corn plants grown in agronomically relevant soils were collected, and microbial populations extracted from the rhizosphere and endosphere. Genomic DNA from these samples was extracted, followed by 16S amplicon sequencing to profile the community composition.
A Kosakonia sacchari microbe (strain PBC6.1) was isolated and classified through 16S rRNA and whole genome sequencing. This is a particularly interesting nitrogen fixer capable of colonizing to nearly 21% abundance of the root-associated microbiota (
We hypothesized that PBC6.1 could be a significant contributor of fixed nitrogen in fertilized fields if regulatory networks controlling nitrogen metabolism were remodeled to allow optimal nitrogenase expression and ammonia release in the presence of fixed nitrogen.
Sufficient genetic diversity should exist within the PBC6.1 genome to enable broad phenotypic remodeling (as a result of remodeling the underlying genetic architecture in a non-intergeneric manner) without the insertion of transgenes or synthetic regulatory elements. The isolated strain has a genome of at least 5.4 Mbp and a canonical nitrogen fixation gene cluster. Related nitrogen metabolism pathways in PBC6.1 are similar to those of the model organism for nitrogen fixation, Klebsiella oxytoca m5a1.
Several gene regulatory network nodes were identified which may augment nitrogen fixation and subsequent transfer to a host plant, particularly in high exogenous concentrations of fixed nitrogen (
The assimilation of fixed nitrogen by the microbe to glutamine by glutamine synthetase (GS) is reversibly regulated by the two-domain adenylyltransferase (ATase) enzyme GlnE through the adenylylation and deadenylylation of GS to attenuate and restore activity, respectively. Truncation of the GlnE protein to delete its adenylyl-removing (AR) domain may lead to constitutively adenylylated glutamine synthetase, limiting ammonia assimilation by the microbe and increasing intra- and extracellular ammonia.
Finally, reducing expression of AmtB, the transporter responsible for uptake of ammonia, could lead to greater extracellular ammonia.
To generate rationally designed microbial phenotypes without the use of transgenes, two approaches were employed to remodel the underlying genetic architecture of the microbe: (1) creating markerless deletions of genomic sequences encoding protein domains or whole genes, and (2) rewiring regulatory networks by intragenomic promoter rearrangement.
Through an iterative remodeling process, several non-transgenic derivative strains of PBC6.1 were generated (Table 25).
Table 25: List of isolated and derivative K. sacchari strains used in this work. Prm, promoter sequence derived from the PBC6.1 genome; ΔglnEAR1 and ΔglnEAR2, different truncated versions of glnE gene removing the adenylyl-removing domain sequence.
Several in vitro assays were performed to characterize specific phenotypes of the derivative strains. The ARA was used to assess strain sensitivity to exogenous nitrogen, in which PBC6.1 exhibited repression of nitrogenase activity at high glutamine concentrations (
Strains with altered GlnE or AmtB activity showed markedly increased ammonium excretion rates compared to wild type or derivative strains without these mutations (
Two experiments were performed to study the interaction of PBC6.1 derivatives (remodeled microbes) with corn plants and quantify incorporation of fixed nitrogen into plant tissues. First, rates of microbial nitrogen fixation were quantified in a greenhouse study using isotopic tracers. Briefly, plants are grown with 15N labeled fertilizer, and diluted concentrations of 15N in plant tissues indicate contributions of fixed nitrogen from microbes. Corn seedlings were inoculated with selected microbial strains, and plants were grown to the V6 growth stage. Plants were subsequently deconstructed to enable measurement of microbial colonization and gene expression as well as measurement of 15N/14N ratios in plant tissues by isotope ratio mass spectrometry (IRMS). Analysis of the aerial tissue showed a small, nonsignificant contribution by PBC6.38 to plant nitrogen levels, and a significant contribution by PBC6.94 (p=0.011). Approximately 20% of the nitrogen found in above-ground corn leaves was produced by PBC6.94, with the remainder coming from the seed, potting mix, or “background” fixation by other soilborne microbes (
Methods
Media
Minimal medium contains (per liter) 25 g Na2HPO4, 0.1 g CaCL2-2H2O, 3 g KH2PO4, 0.25 g MgSO4.7H2O, 1 g NaCl, 2.9 mg FeCl3, 0.25 mg Na2MoO4.2H2O, and 20 g sucrose. Growth medium is defined as minimal medium supplemented with 50 ml of 200 mM glutamine per liter.
Corn seedlings were grown from seed (DKC 66-40, DeKalb, Ill.) for two weeks in a greenhouse environment controlled from 22° C. (night) to 26° C. (day) and exposed to 16 hour light cycles in soil collected from San Joaquin County, Calif. Roots were harvested and washed with sterile deionized water to remove bulk soil. Root tissues were homogenized with 2 mm stainless steel beads in a tissue lyser (TissueLyser II, Qiagen P/N 85300) for three minutes at setting 30, and the samples were centrifuged for 1 minute at 13,000 rpm to separate tissue from root-associated bacteria. Supernatants were split into two fractions, and one was used to characterize the microbiome through 16S rRNA amplicon sequencing and the remaining fraction was diluted and plated on Nitrogen-free Broth (NfB) media supplemented with 1.5% agar. Plates were incubated at 30° C. for 5-7 days. Colonies that emerged were tested for the presence of the nifH gene by colony PCR with primers Ueda19f and Ueda406r. Genomic DNA from strains with a positive nifH colony PCR was isolated (QIAamp DNA Mini Kit, Cat No. 51306, QIAGEN, Germany) and sequenced (Illumina MiSeq v3, SeqMatic, Fremont, Calif.). Following sequence assembly and annotation, the isolates containing nitrogen fixation gene clusters were utilized in downstream research.
Genomic DNA was isolated from root-associated bacteria using the ZR-96 Genomic DNA I Kit (Zymo Research P/N D3011), and 16S rRNA amplicons were generated using nextera-barcoded primers targeting 799f and 1114r. The amplicon libraries were purified and sequenced with the Illumina MiSeq v3 platform (SeqMatic, Fremont, Calif.). Reads were taxonomically classified using Kraken using the minikraken database (
A modified version of the Acetylene Reduction Assay was used to measure nitrogenase activity in pure culture conditions. Strains were propagated from single colony in SOB (RPI, P/N S25040-1000) at 30° C. with shaking at 200 RPM for 24 hours and then subcultured 1:25 into growth medium and grown aerobically for 24 hours (30° C., 200 RPM). 1 ml of the minimal media culture was then added to 4 ml of minimal media supplemented with 0 to 10 mM glutamine in air-tight Hungate tubes and grown anaerobically for 4 hours (30° C., 200 RPM). 10% headspace was removed then replaced by an equal volume of acetylene by injection, and incubation continued for 1 hr. Subsequently, 2 ml of headspace was removed via gas tight syringe for quantification of ethylene production using an Agilent 6850 gas chromatograph equipped with a flame ionization detector (FID).
Excretion of fixed nitrogen in the form of ammonia was measured using batch fermentation in anaerobic bioreactors. Strains were propagated from single colony in 1 ml/well of SOB in a 96 well DeepWell plate. The plate was incubated at 30° C. with shaking at 200 RPM for 24 hours and then diluted 1:25 into a fresh plate containing 1 ml/well of growth medium. Cells were incubated for 24 hours (30° C., 200 RPM) and then diluted 1:10 into a fresh plate containing minimal medium. The plate was transferred to an anaerobic chamber with a gas mixture of >98.5% nitrogen, 1.2-1.5% hydrogen and <30 ppM oxygen and incubated at 1350 RPM, room temperature for 66-70 hrs. Initial culture biomass was compared to ending biomass by measuring optical density at 590 nm. Cells were then separated by centrifugation, and supernatant from the reactor broth was assayed for free ammonia using the Megazyme Ammonia Assay kit (P/N K-AMIAR) normalized to biomass at each timepoint.
Roots were shaken gently to remove loose particles, and root systems were separated and soaked in a RNA stabilization solution (Thermo Fisher P/N AM7021) for 30 minutes. The roots were then briefly rinsed with sterile deionized water. Samples were homogenized using bead beating with ½-inch stainless steel ball bearings in a tissue lyser (TissueLyser II, Qiagen P/N 85300) in 2 ml of lysis buffer (Qiagen P/N 79216). Genomic DNA extraction was performed with ZR-96 Quick-gDNA kit (Zymo Research P/N D3010), and RNA extraction using the RNeasy kit (Qiagen P/N 74104).
Four days after planting, 1 ml of a bacterial overnight culture (approximately 109 cfu) was applied to the soil above the planted seed. Seedlings were fertilized three times weekly with 25 ml modified Hoagland's solution supplemented with 0.5 mM ammonium nitrate. Four weeks after planting, root samples were collected and the total genomic DNA (gDNA) was extracted. Root colonization was quantified using qPCR with primers designed to amplify unique regions of either the wild type or derivative strain genome. QPCR reaction efficiency was measured using a standard curve generated from a known quantity of gDNA from the target genome. Data was normalized to genome copies per g fresh weight using the tissue weight and extraction volume. For each experiment, the colonization numbers were compared to untreated control seedlings.
Transcriptional profiling of root-associated microbes was measured in seedlings grown and processed as described in the Root Colonization Assay. Purified RNA was sequenced using the Illumina NextSeq platform (SeqMatic, Fremont, Calif.). Reads were mapped to the genome of the inoculated strain using bowtie2 using ‘—very-sensitive-local’ parameters and a minimum alignment score of 30. Coverage across the genome was calculated using samtools. Differential coverage was normalized to housekeeping gene expression and visualized across the genome using Circos and across the nif gene cluster using DNAplotlib. Additionally, the in planta transcriptional profile was quantified via targeted Nanostring analysis. Purified RNA was processed on an nCounter Sprint (Core Diagnostics, Hayward, Calif.).
A 15N fertilizer dilution experiment was performed to assess optimized strain activity in planta. A planting medium containing minimal background N was prepared using a mixture of vermiculite and washed sand (5 rinses in DI H2O). The sand mixture was autoclaved for 1 hour at 122° C. and approximately 600 g measured out into 40 cubic inch (656 mL) pots, which were saturated with sterile DI H2O and allowed to drain 24 hours before planting. Corn seeds (DKC 66-40) were surface sterilized in 0.625% sodium hypochlorite for 10 minutes, then rinsed five times in sterile distilled water and planted 1 cm deep. The plants were maintained under fluorescent lamps for four weeks with 16-hour day length at room temperatures averaging 22° C. (night) to 26° C. (day).
Five days after planting, seedlings were inoculated with a 1 ml suspension of cells drenched directly over the emerging coleoptile. Inoculum was prepared from 5 ml overnight cultures in SOB, which were spun down and resuspended twice in 5 ml PBS to remove residual SOB before final dilution to OD of 1.0 (approximately 109 CFU/ml). Control plants were treated with sterile PBS, and each treatment was applied to ten replicate plants.
Plants were fertilized with 25 ml fertilizer solution containing 2% 15N-enriched 2 mM KNO3 on 5, 9, 14, and 19 days after planting, and the same solution without KNO3 on 7, 12, 16, and 18 days after planting. The fertilizer solution contained (per liter) 3 mmol CaCl2, 0.5 mmol KH2PO4, 2 mmol MgSO4, 17.9 μmol FeSO4, 2.86 mg H3BO3, 1.81 mg MnCl2.4H2O, 0.22 mg ZnSO4.7H2O, 51 μg CuSO4.5H2O, 0.12 mg Na2MoO4.2H2O, and 0.14 nmol NiCl2. All pots were watered with sterile DI H2O as needed to maintain consistent soil moisture without runoff.
At four weeks, plants were harvested and separated at the lowest node into samples for root gDNA and RNA extraction and aerial tissue for IRMS. Aerial tissues were wiped as needed to remove sand, placed whole into paper bags and dried for at least 72 hours at 60° C. Once completely dry, total aerial tissue was homogenized by bead beating and 5-7 mg samples were analyzed by isotope ratio mass spectrometry (IRMS) for M5N by the MBL Stable Isotope Laboratory (The Ecosystems Center, Woods Hole, Mass.). Percent NDFA was calculated using the following formula: % NDFA=(δ15N of UTC average−δ15N of sample)/(δ15N of UTC average)×100.
In order to evaluate the efficacy of remodeled strains of the present disclosure on corn growth and productivity under varying nitrogen regimes, field trials were conducted.
Trials were conducted with (1) seven subplot treatments of six strains plus the control—four main plots comprised 0, 15, 85, and 100% of maximum return to nitrogen (MRTN) with local verification. The control (UTC only) was conducted with 10 100% MRTN plus, 5, 10, or 15 pounds. Treatments had four replications.
Plots of corn (minimum) were 4 rows of 30 feet in length, with 124 plots per location. All observations were taken from the center two rows of the plots, and all destructive sampling was taken from the outside rows. Seed samples were refrigerated until 1.5 to 2 hours prior to use.
Local Agricultural Practice: The seed was a commercial corn without conventional fungicide and insecticide treatment. All seed treatments were applied by a single seed treatment specialist to assure uniformity. Planting date, seeding rate, weed/insect management, etc. were left to local agricultural practices. With the exception of fungicide applications, standard management practices were followed.
Soil Characterization: Soil texture and soil fertility were evaluated. Soil samples were pre-planted for each replicate to insure residual nitrate levels lower than 50 lbs/Ac. Soil cores were taken from 0 cm to 30 cm. The soil was further characterized for pH, CEC, total K and P.
Assessments: The initial plant population was assessed 14 days after planting (DAP)/acre, and were further assessed for: (1) vigor (1 to 10 scale, w/10=excellent) 14 DAP & V10; (2) recordation of disease ratings any time symptoms are evident in the plots; (3) record any differences in lodging if lodging occurs in the plots; (4) yield (Bu/acre), adjusted to standard moisture pct; (5) test weight; and (6) grain moisture percentage.
Sampling Requirements: The soil was sampled at three timepoints (prior to trial initiation, V10-VT, 1 week post-harvest). All six locations and all plots were sampled at 10 grams per sample (124 plots×3 timepoints×6 locations).
Colonization Sampling: Colonization samples were collected at two timepoints (V10 and VT) for five locations and six timepoints (V4, V8, V10, VT, R5, and Post-Harvest). Samples were collected as follows: (1) from 0% and 100% MRTN, 60 plots per location; (2) 4 plants per plot randomly selected from the outside rows; (3) 5 grams of root, 8 inches of stalk, and top three leaves-bagged and IDed each separately—12/bags per plot; (4) five locations (60 plots×2 timepoints×12 bags/plot); and one location (60 plots×6 timepoints×12 bags/plot.
Normalized difference vegetation index (NDVI) determination was made using a Greenseeker instrument at two timepoints (V4-V6 and VT). Assessed each plot at all six locations (124 plots×2 timepoints×6 locations).
Root analysis was performed with Win Rhizo from one location that best illustrated treatment differentiation. Ten plants per plot were randomly sampled (5 adjacent from each outside row; V3-V4 stage plants were preferred) and gently washed to remove as much dirt as reasonable. Ten roots were placed in a plastic bag and labelled. Analyzed with WinRhizo Root Analysis.
Stalk Characteristics were measured at all six locations between R2 and R5. The stalk diameter of ten plants per plot at the 6″ height were recorded, as was the length of the first internode above the 6″ mark. Ten plants were monitored; five consecutive plants from the center of the two inside rows. Six locations were evaluated (124 plots×2 measures×6 locations).
The tissue nitrates were analyzed from all plots and all locations. An 8″ segment of stalk beginning 6″ above the soil when the corn is between one and three weeks after black layer formation; leaf sheaths were removed. All locations and plots were evaluated (6 locations×124 plots).
The following weather data was recorded for all locations from planting to harvest: daily maximum and minimum temperatures, soil temperature at seeding, daily rainfall plus irrigation (if applied), and any unusual weather events such as excessive rain, wind, cold, or heat.
Yield data across all six locations is presented in Table 26. Nitrogen rate had a significant impact on yield, but strains across nitrogen rates did not. However, at the lowest nitrogen rate, strains C1006, CM029, and C1019 numerically out-yielded the UTC by 4 to 6 bu/acre. Yield was also numerically increased 2 to 4 bu/acre by strains CM029, C1019, and CM081 at 15% MRTN.
Another analysis approach is presented in Table 27. The table comprises the four locations where the response to nitrogen was the greatest which suggests that available residual nitrogen was lowest. This approach does not alter the assessment that the nitrogen rate significantly impacted yield, which strains did not when averaged across all nitrogen rates. However, the numerical yield advantage at the lowest N rate is more pronounced for all strains, particularly C1006, CM029, and CM029/CM081 where yields were increased from 8 to 10 bu/acre. At 15% MRTN, strain CM081 outyielded UTC by 5 bu.
The results from the field trial are also illustrated in
The field based results further validate the disclosed methods of non-intergenerically modifying the genome of selected microbial strains, in order to bring about agriculturally relevant results in a field setting when applying said engineered strains to a crop.
Further, one can see in Table 27 that the combination of CM029/CM081 at 0% MRTN yielded 141.4 bu/acre compared to untreated control at 131.9 bu/acre (an increase of 9.5 bu/acre).
In order to evaluate the efficacy of remodeled strains of the present disclosure on corn growth and productivity under varying nitrogen regimes, field trials were conducted. The below field data demonstrates that the non-intergeneric microbes of the disclosure are able to fix atmospheric nitrogen and deliver said nitrogen to a plant—resulting in increased yields— in both a nitrogen limiting environment, as well as a non-nitrogen limiting environment.
Trials were conducted at seven locations across the United States with six geographically diverse Midwestern locations. Five nitrogen regimes were used for fertilizer treatments: 100% of standard agricultural practice of the site/region, 100% minus 25 pounds, 100% minus 50 pounds, 100% minus 75 pounds, and 0%; all per acre. The pounds of nitrogen per acre for the 100% regime depended upon the standard agricultural practices of the site/region. The aforementioned nitrogen regimes ranged from about 153 pounds per acre to about 180 pounds per acre, with an average of about 164 pounds of nitrogen per acre.
Within each fertilizer regime there were 14 treatments. Each regime had six replications, and a split plot design was utilized. The 14 treatments included: 12 different microbes, 1 UTC with the same fertilizer rate as the main plot, and 1 UTC with 100% nitrogen. In the 100% nitrogen regime the 2nd UTC is 100 plus 25 pounds.
Plots of corn, at a minimum, were 4 rows of 30 feet in length (30 inches between rows) with 420 plots per location. All observations, unless otherwise noted, were taken from the center two rows of the plants, and all destructive sampling was taken from the outside rows. Seed samples were refrigerated until 1.5 to 2 hours prior to use.
Local Agricultural Practice: The seed was a commercial corn applied with a commercial seed treatment with no biological co-application. The seeding rate, planting date, weed/insect management, harvest times, and other standard management practices were left to the norms of local agricultural practices for the regions, with the exception of fungicide application (if required).
Microbe Application: The microbes were applied to the seed in a seed treatment over seeds that had already received a normal chemical treatment. The seed were coated with fermentation broth comprising the microbes.
Soil Characterization: Soil texture and soil fertility were evaluated. Standard soil sampling procedures were utilized, which included soil cores of depths from 0-30 cm and 30-60 cm. The standard soil sampling included a determination of nitrate nitrogen, ammonium nitrogen, total nitrogen, organic matter, and CEC. Standard soil sampling further included a determination of pH, total potassium, and total phosphorous. To determine the nitrogen fertilizer levels, preplant soil samples from each location were taken to ensure that the 0-12″ and potentially the 12″ to 24″ soil regions for nitrate nitrogen.
Prior to planting and fertilization, 2 ml soil samples were collected from 0 to 6-12″ from the UTC. One sample per replicate per nitrogen region was collected using the middle of the row. (5 fertilizer regimes×6 replicates=thirty soil samples).
Post-planting (V4-V6), 2 ml soil samples were collected from 0 to 6-12″ from the UTC. One sample per replicate per nitrogen region was collected using the middle of the row. (5 fertilizer regimes×6 replicates=thirty soil samples).
Post-harvest (V4-V6), 2 ml soil samples were collected from 0 to 6-12″ from the UTC. One sample per replicate per nitrogen region was collected using the middle of the row. Additional post-harvest soil sample collected at 0-12″ from the UTC and potentially 12-24″ from the UTC (5 fertilizer regimes×6 replicates=thirty soil samples).
A V6-V10 soil sample from each fertilizer regime (excluding the treatment of 100% and 100%+25 lbs [in the 100% block] for all fertilizer regimes at 0-12″ and 12-24″. (5 fertilizer regimes×2 depths=10 samples per location).
Post-harvest soil sample from each fertilizer regime (excluding the treatment of 100% and 100%+25 lbs [in the 100% block] for all fertilizer regimes at 0-12″ and 12-24″. (5 fertilizer regimes×2 depths=10 samples per location).
Assessments: The initial plant population was assessed at ˜50% UTC and the final plant population was assessed prior to harvest. Assessment included (1) potentially temperature (temperature probe); (2) vigor (1-10 scale with 10=excellent) at V4 and V8-V10; (3) plant height at V8-V10 and V14; (4) yield (bushels/acre) adjusted to standard moisture percentage; (5) test weight; (6) grain moisture percentage; (7) stalk nitrate tests at black layer (420 plots×7 locations); (8) colonization with 1 plant per plot in zip lock bag at 0% and 100% fertilizer at V4-V6 (1 plant×14 treatments×6 replicates×2 fertilizer regimes=168 plants); (9) transcriptomics with 1 plant per plot in zip lock bag at 0% and 100% fertilizer at V4-V6 (1 plant×14 treatments×6 replicates×2 fertilizer regimes=168 plants); (10) Normalized difference vegetative index (NDVI) or normalized difference red edge (NDRE) determination using a Greenseeker instrument at two time points (V4-V6 and VT) to assess each plot at all 7 locations (420 plots×2 time points×7 locations=5,880 data points); (11) stalk characteristics measured at all 7 locations between R2 and R5 by recording the stalk diameter of 10 plants/plot at 6″ height, record length of first internode above the 6″ mark, 10 plants monitored (5 consecutive plants from center of two inside rows) (420 plots×10 plants×7 locations=29,400 data points).
Monitoring Schedule: Practitioners visited all trials at V3-V4 stage to assess early-season response to treatments and during reproductive growth stage to monitor maturity. Local cooperator visited research trial on an on-going basis.
Weather Information: Weather data spanning from planting to harvest was collected and consisted of daily minimum and maximum temperatures, soil temperature at seeding, daily rainfall plus irrigation (if applied), and unusual weather events such as excessive wind, rain, cold, heat.
Data Reporting: Including the data indicated above, the field trials generated data points including soil textures; row spacing; plot sizes; irrigation; tillage; previous crop; seeding rate; plant population; seasonal fertilizer inputs including source, rate, timing, and placement; harvest area dimensions, method of harvest, such as by hand or machine and measurement tools used (scales, yield monitor, etc.)
Results: Select results from the aforementioned field trial are reported in
In
In
The remodeled microbes of the present disclosure were evaluated and compared against one another for the production of nitrogen produced in an acre across a season. See
It is hypothesized by the inventors that in order for a population of engineered non-intergeneric microbes to be beneficial in a modern row crop agricultural system, then the population of microbes needs to produce at least one pound or more of nitrogen per acre per season.
To that end, the inventors have surprisingly discovered a functional genus of microbes that are able to contribute, inter alia, to: increasing yields in non-leguminous crops; and/or lessening a farmer's dependence upon exogenous nitrogen application; and/or the ability to produce at least one pound of nitrogen per acre per season, even in non-nitrogen-limiting environments, said genus being defined by the product of colonization ability×mmol of N produced per microbe per hour (i.e. the line partitioning
With respect to
Field Data & Wild Type Colonization Heatmap: The microbes utilized in the
Field Data Heatmap: The data utilized in the
Greenhouse & Laboratory Data Heatmap: The data utilized in the
Kosakonia sacchari
Kosakonia sacchari
Kosakonia sacchari
Kosakonia sacchari
Kosakonia sacchari
Kosakonia sacchari
Rahnella aquatilis
Rahnella aquatilis
Rahnella aquatilis
Rahnella aquatilis
Klebsiella variicola
Klebsiella variicola
Klebsiella variicola
Klebsiella variicola
Klebsiella variicola
Rahnella aquatilis
Rahnella aquatilis
Kosakonia
pseudosacchari
Klebsiella variicola
Kosakonia sacchari
Kosakonia sacchari
Kosakonia sacchari
Klebsiella variicola
Klebsiella variicola
Klebsiella variicola
Kosakonia
pseudosacchari
Kosakonia
pseudosacchari
Kosakonia
pseudosacchari
Kosakonia
pseudosacchari
Kosakonia
pseudosacchari
Azospirillum
lipoferum
Enterobacter sp.
Enterobacter sp.
Kluyvera intermedia
Kluyvera intermedia
Achromobacter
spiritinus
Achromobacter
marplatensis
Microbacterium
murale
Conclusions: The data in
Consequently, the newly discovered genus is supported by: (1) a robust dataset, (2) over a dozen representative members, (3) members from diverse taxonomic genera, and (4) classes of genetic modifications that define a structure/function relationship, in the underlying genetic architecture of the genus members.
The present disclosure teaches primers, probes, and assays that are useful for detecting the microbes utilized in the various aforementioned Examples. The assays are able to detect the non-natural nucleotide “junction” sequences in the derived/mutant non-intergeneric remodeled microbes. These non-naturally occurring nucleotide junctions can be used as a type of diagnostic that is indicative of the presence of a particular genetic alteration in a microbe.
The present techniques are able to detect these non-naturally occurring nucleotide junctions via the utilization of specialized quantitative PCR methods, including uniquely designed primers and probes. The probes can bind to the non-naturally occurring nucleotide junction sequences. That is, sequence-specific DNA probes consisting of oligonucleotides that are labelled with a fluorescent reporter, which permits detection only after hybridization of the probe with its complementary sequence can be used. The quantitative methods can ensure that only the non-naturally occurring nucleotide junction will be amplified via the taught primers, and consequently can be detected either via a non-specific dye, or via the utilization of a specific hybridization probe. Another aspect of the method is to choose primers such that the primers flank either side of a junction sequence, such that if an amplification reaction occurs, then said junction sequence is present.
Consequently, genomic DNA can be extracted from samples and used to quantify the presence of microbes of the disclosure by using qPCR. The primers utilized in the qPCR reaction can be primers designed by Primer Blast (www.ncbi.nlm.nih.gov/tools/primer-blast/) to amplify unique regions of the wild-type genome or unique regions of the engineered non-intergeneric mutant strains. The qPCR reaction can be carried out using the SYBR GreenER qPCR SuperMix Universal (Thermo Fisher P/N 11762100) kit, using only forward and reverse amplification primers; alternatively, the Kapa Probe Force kit (Kapa Biosystems P/N KK4301) can be used with amplification primers and a TaqMan probe containing a FAM dye label at the 5′ end, an internal ZEN quencher, and a minor groove binder and fluorescent quencher at the 3′ end (Integrated DNA Technologies).
Certain primer, probe, and non-native junction sequences—which can be used in the qPCR methods—are listed in the below Table 30. Specifically, the non-native junction sequences can be found in SEQ ID NOs: 372-405 and 425-457.
Sustainable production of grains such as corn, wheat, and rice require the application of some source of nitrogen. Growers apply nitrogen that plants can use in a number of forms. In geographies where livestock production is intense, livestock manure can meet a significant portion of the nitrogen needs of a corn crop. Where no organic form of nitrogen is available, commercial nitrogen fertilizers either in the form of a gas held under pressure as a liquid (NH3) a dry formulation such as ammonium nitrate or urea, or in liquid formulations such as combinations of urea and ammonia nitrate (UAN).
The point in time when nitrogen is applied to corn depends upon a number of factors. The first of these may be local or state regulations. Other factors that may affect when a grower chooses to apply nitrogen would be field-working conditions in the fall (still a popular application timing for many geographies) due to uncertainty around cropping plans, Spring weather, and planting conditions and the size of the operation.
Growers may apply nitrogen in the fall, after the previous crop is removed. This application timing, while popular, is under attack by regulatory agencies who are seeking to limit either the number of pounds that can be applied in the Fall or the Fall application entirely. If no Fall application occurs, then growers will usually apply nitrogen prior to planting the corn crop, after crop emergence, or a combination of the two, which is referred to as a split application.
In any of the aforementioned nitrogen delivery regimes, the second application of nitrogen, which normally occurs at the V4-V6 stage, is referred to as a sidedress application. The sidedress application of nitrogen is often applied between the rows.
Due to the instability of nitrogen molecules once they are in the soil, research has demonstrated that if a grower can apply the nitrogen as close to when the corn crop needs the nitrogen, there are significant benefits for the crop as well as for the environment. The nitrogen use efficiency increases, meaning it takes less pounds of nitrogen to produce a bushel.
Sidedressing is not without risks. The ability to get across all of a grower's acres in a timely manner is not ensured. These risks increase as the size of the operation increases and as potential changes to the climate make the number of days suitable for fieldwork less predictable.
An alternative to the use of commercial fertilizer for legumes (primarily soybeans) has been biological nitrogen fixing (BNF) systems, which exist in nature. These systems fall into one of three types and differ in their use of substrate and efficiency. See
An example of where the majority of the nitrogen needs of the crop are met through a symbiotic relationship with the plant would be that of soybeans or alfalfa. They are capable of converting almost enough molecular nitrogen (N2) to meet the nitrogen needs of the crop. In the case of soybeans, many farmers apply Rhizobium at the time of planting, but some Rhizobium are ubiquitous in most soils and populations are able to survive in the soil from year to year.
The ability to produce a microbe that would be able to convert N2 to NH3 through root association in cereals such as corn, rice, or wheat would be revolutionary and the equivalent of BNF in soybeans. It could also replace sidedressing since both practices would allow for the timely delivery of nitrogen to the growing plant in season. BNF for cereals would also allow growers to reduce the risks associated with sidedressing. These risks include reduced yields due to untimely applications, variable in-season cost of nitrogen, the cost of application, and consistency of nitrogen availability in years when environmental conditions are conducive to loss through de-nitrification or leaching. BNF for cereals would also create value through ease of use and reducing passes over the field for specific nitrogen applications.
As can be seen from the below Table B, Fall and Spring nitrogen application strategies always use sidedress. The split application also features sidedressing. The state of the art is such that sidedressing is an energy intensive mechanical process that is applied by a tractor that compacts the soil. Often at stage V4-V6, additional nitrogen is applied as sidedressing.
The disclosed remodeled nitrogen fixing bacteria are able to eliminate the practice of sidedressing, as these bacteria live in intimate association with the plant's root system and “spoonfeed” the plant nitrogen.
Thus, as can be seen in Table B, the present disclosure provides an alternative to traditional synthetic fertilizer sidedressing, by allowing a farmer to utilize an “ecological sidedressing” comprised of non-intergeneric remodeled bacteria that are capable of fixing atmospheric nitrogen and delivering such to the corn plant throughout the corn's growth cycle.
The microbes of the disclosure are engineered with one or more of the following features, in order to develop non-intergeneric remodeled microbes that are capable of colonizing corn and supplying fixed nitrogen to the corn, at physiologically relevant periods of the corn's life cycle.
These genetic modifications, in some aspects, have been discussed previously, inter alia, in Examples 2-6. They are discussed again here, in order to provide the building blocks of a Guided Microbial Remodeling (GMR) campaign, which will be elaborated upon below.
Feature: Nitrogenase Expression—nifL Deletion and Promoter Insertion Upstream of nifA.
NifA activates the nif gene complex and drives nitrogen fixation when there is insufficient fixed nitrogen available to the microbe. NifL inhibits NifA when there is sufficient fixed N available to the microbe. The nifL and nifA genes are present in an operon and are driven by the same promoter upstream of nifL, which is activated in conditions of nitrogen insufficiency and repressed in conditions of nitrogen sufficiency (
Feature: Nitrogenase Expression—Promoter Swap of the rpoN Gene to Increase Availability of Sigma Factor 54
Sigma factors are required for initiation of transcription of prokaryotic genes, and sometimes specific sigma factors initiate the transcription of a set of genes in a common regulatory network. Sigma 54 (σ54), encoded by the gene rpoN, is responsible for transcription of many genes involved in nitrogen metabolism, including the nif cluster and nitrogen assimilation genes (Klipp et al. 2005, Genetics and Regulation of Nitrogen Fixation in Free-Living Bacteria, Kluwer Academic Publishers (Vol. 2). doi.org/10.1007/1-4020-2179-8). In strains where nifA is controlled by a strong promoter active in nitrogen replete conditions, the availability of σ54 to initiate transcription of the nif genes may become limiting. In this feature, the promoter of the rpoN gene has been disrupted by deleting the intergenic sequence immediately upstream of the gene. The deleted sequence was replaced by a different promoter naturally present elsewhere in the genome of the wild-type strain, which we have observed is highly expressed in nitrogen-replete conditions. This results in increased expression of σ54 which relieves any limitation on transcription initiation in strains highly expressing nifA.
Feature: Nitrogen Assimilation—Deletion of the Adenylyl-Removing Domain of GlnE
Fixed nitrogen is primarily assimilated by the microbe by the glutamine synthetase/glutamine oxoglutarate aminotransferase (GS-GOGAT) pathway. The resulting glutamine and glutamate pools in the cell control nitrogen metabolism, with glutamate serving as the main nitrogen pool for biosynthesis and glutamine serving as the signaling molecule for nitrogen status. The glnE gene encodes an enzyme, known as glutamine synthetase adenylyl transferase or glutamine-ammonia-ligase adenylyl transferase, that regulates the activity of glutamine synthetase (GS), in response to intracellular levels of glutamine. The GlnE protein consists of two domains with independent and distinct enzymatic activities: an adenylyltransferase (ATase) domain, which covalently modifies the GS protein with an adenylyl group, thus reducing GS activity; and an adenylyl-removing (AR) domain, which removes the adenylyl group from GS, thus increasing its activity. Clancy et al. (2007) showed that truncation of the Escherichia coli K12 GlnE protein to remove the AR domain lead to expression of a protein that retains ATase activity. In this feature, we have deleted the N-terminal AR domain of GlnE, resulting in a strain lacking the AR activity, but functionally expressing the ATase domain. This leads to constitutively adenylated GS with attenuated activity, causing a reduction in assimilation of ammonium and excretion of ammonium out of the cell.
Feature: Nitrogen Assimilation—Decrease Transcription and/or Translation Rates of Gene Encoding GS
The glnA gene, which encodes the GS enzyme, is controlled by a promoter which is activated under nitrogen depletion, and repressed under nitrogen replete conditions (Van Heeswijk et al. 2013). In this feature, the amount of GS enzyme in the cell has been decreased in at least one of two ways (or a combination of the following two ways into one cell). First, the “A” of the ATG start codon of the glnA gene, which encodes glutamine synthetase (GS), has been changed to “G”. The rest of the glnA gene and GS protein sequence remains unaltered. The resulting GTG start codon is hypothesized to result in a decreased translation initiation rate of the glnA transcript, leading to a decrease in the intracellular level of GS. Second, the promoter upstream of the glnA gene has been disrupted by deleting the intergenic sequence immediately upstream of the gene. The deleted sequence was replaced by the promoter of the glnD, glnE or glnB genes, which are expressed constitutively at a very low level regardless of nitrogen status (Van Heeswijk et al 2013). This leads to a decrease in glnA transcription levels s and therefore a decrease in GS levels in the cell. As aforementioned, the previous two scenarios (alteration of start codon and promoter disruption) can be combined into a host. The decreased GS activity in the cell leads to a decrease in the bacterial assimilation of the ammonium produced by nitrogen fixation, resulting in excretion of ammonium outside of the bacterial cell, making nitrogen more available for plant uptake (Ortiz-Marquez, J. C. F., Do Nascimento, M., & Curatti, L. (2014) “Metabolic engineering of ammonium release for nitrogen-fixing multispecies microbial cell-factories,” Metabolic Engineering, 23, 1-11. doi.org/10.1016/j.ymben.2014.03.002).
Feature: Nitrogen Assimilation—Promoter Swap of the glsA2 Gene to Increase Glutaminase Activity
Glutaminase enzymes catalyze the release of ammonium from glutamine and may play an important role in controlling the intracellular glutamine pool (Van Heeswijk et al. 2012). In this feature, the glsA2 gene encoding glutaminase has been upregulated by deleting a sequence immediately upstream of the gene and replacing it with different promoter naturally present elsewhere in the genome which is highly expressed in nitrogen-replete conditions. This results in increased expression of glutaminase enzyme in the cell, leading to release of ammonium from the glutamine pool and therefore increased excretion of ammonium out of the cell.
Feature: Ammonium Excretion—amtB Deletion
The amtB gene encodes a transport protein that functions to import ammonium from the extracellular space into the cell interior. It is believed that in nitrogen-fixing bacteria, the AmtB protein functions to ensure that any ammonium that passively diffuses out of the cell during nitrogen fixation is imported back into the cell, thus preventing loss of fixed nitrogen (Zhang et al. 2012). In this feature, the amtB coding sequence has been deleted, leading to net diffusion of ammonium out of the cell and thus an increase in ammonium excretion (Barney et al. 2015). The amtB promoter has been left intact.
Feature: Robustness and Colonization—Promoter Swap of bcsII and bcsIII Operons to Increase Bacterial Cellulose Production
Bacterial cellulose biosynthesis is an important factor for both attachment to the root and biofilm formation on root surfaces (Rodriguez-Navarro et al. 2007). The bcsII and bcsIII operons each encode a set of genes involved in bacterial cellulose biosynthesis (Ji et al. 2016). In this feature, the native promoter of the bcsII operon has been disrupted by deleting the intergenic region upstream of the first gene in the operon and replacing it with a different promoter naturally present elsewhere in the genome of the wild-type strain which we have observed is highly expressed in nitrogen-replete conditions. This results in increased expression of the bcsII operon in a fertilized-field environment, which leads to an increase in bacterial cellulose production and thus attachment to corn roots.
Feature: Promoter Swap of pehA Operon to Increase Polygalacturonase Production
Polygalacturonases are implicated as important factors for colonization of plant roots by non-nodule-forming bacteria (Compant, S., Clement, C., & Sessitsch, A. (2010), “Plant growth-promoting bacteria in the rhizo- and endosphere of plants: Their role, colonization, mechanisms involved and prospects for utilization,” Soil Biology and Biochemistry, 42(5), 669-678. doi.org/10.1016/j.soilbio.2009.11.024.)
The pehA gene encodes a polygalacturonase in an operon with two uncharacterized protein coding regions, with the pehA at the downstream end of the operon. In this feature, the promoter of the pehA operon has been disrupted by deleting a sequence immediately upstream of the first gene in the operon. The deleted sequence was replaced by a different promoter naturally present elsewhere in the genome of the wild-type strain, which we have observed is highly expressed in nitrogen-replete conditions. This results in increased expression of the PehA polygalacturonase protein in a fertilized-field environment, which leads to enhanced colonization of corn roots by the microbe.
Feature: Robustness and Colonization—Promoter Swap of the fhaB Gene to Increase Expression of Adhesins
Bacterial surface adhesins, such as agglutinins, have been implicated in attachment, colony and biofilm formation on plant roots (Danhorn, T., & Fuqua, C. (2007), “Biofilm formation by plant-associated bacteria. Annual Review of Microbiology, 61, 401-422. doi.org/10.1146/annurev.micro.61.080706.093316).
The fhaB gene encodes a filamentous hemagglutinin protein. In this feature, the promoter of the fhaB gene has been disrupted by deleting the intergenic sequence immediately upstream of the gene. The deleted sequence was replaced by a different promoter naturally present elsewhere in the genome of the wild-type strain, which we have observed is highly expressed in nitrogen-replete conditions. This results in increased expression of the hemagglutinin protein, leading to increased root attachment and colonization.
Feature: Robustness and Colonization—Promoter Swap of the dctA Gene to Increase Expression of Organic Acid Transporters
For successful colonization of the rhizosphere, a bacterium must have the ability to utilize carbon sources found in root exudates, such as organic acids. The gene dctA encodes an organic acid transporter that has been shown to be necessary for effective colonization in rhizosphere bacteria and repressed in response to exogenous nitrogen (Nam, H. S., Anderson, A. J., Yang, K. Y., Cho, B. H., & Kim, Y. C. (2006), “The dctA gene of Pseudomonas chlororaphis O6 is under RpoN control and is required for effective root colonization and induction of systemic resistance,” FEMS Microbiology Letters, 256(1), 98-104. doi.org/10.1111/j.1574-6968.2006.00092.x). In this feature, the promoter of the dctA gene has been disrupted by deleting the intergenic sequence immediately upstream of the gene. The deleted sequence was replaced by a different promoter naturally present elsewhere in the genome of the wild-type strain, which we have observed is highly expressed in the rhizosphere in nitrogen-replete conditions. This results in increased expression of the DctA transporter, enhanced utilization of root exudate carbon and thus improved robustness in fertilized-field conditions.
Feature: Robustness and Colonization—Promoter Swap of the PhoB Gene to Promote Biofilm Formation
In rhizosphere bacteria, the PhoR-PhoB two-component system mediates a response to phosphorous limitation and has been linked to colony and biofilm formation on plant roots (Danhorn and Fuqua 2007). In this feature, the promoter of the phoB1 gene has been disrupted by deleting the intergenic sequence immediately upstream of the gene. The deleted sequence was replaced by a different promoter naturally present elsewhere in the genome of the wild-type strain, which we have observed is highly expressed in the rhizosphere in nitrogen-replete conditions. This results in increased expression of the PhoB component of the PhoR-PhoB system, leading to enhanced colony and biofilm formation on roots.
Feature: Correlated Metabolic and Regulatory Networks—Altering Nitrogen Signaling to Influence Stress Response
GlnD is the central nitrogen-sensing enzyme in the cell. The GlnD protein consists of three domains: a uridylyl-transferase (UTase) domain, and (UR) uridylyl-removing domain, and a glutamine-binding ACT domain. In nitrogen-excess conditions, intracellular glutamine binds to the ACT domain of GlnD, causing the UTase domain to uridylylate the PII proteins GlnB and GlnK, causing a regulatory cascade upregulating genes involved in nitrogen fixation and assimilation. In nitrogen starvation conditions, glutamine is not available to bind to the ACT domain of GlnD, which causes the UR domain to de-uridylylate GlnK and GlnB, which causes repression of genes involved in nitrogen assimilation and repression. These PII regulatory cascades regulate several pathways, including nitrogen starvation stress responses, nitrogen assimilation and nitrogen fixation in diazotrophs (Dixon and Kahn 2004; van Heeswijk et al. 2013). In this feature, either the UTase domain, the UR domain, the ACT domain, or the entire gene encoding the GlnD protein has been modified in order to alter the transduction of nitrogen starvation signals which cause stress responses.
Feature: Correlated Metabolic and Regulatory Networks—Deletion of the glgA Glycogen Synthase Gene
Because nitrogen fixation is such an energy-intensive process, it is believed to be limited by the availability of ATP in the cell. It has therefore been hypothesized that diverting carbon away from energy storage pathways and towards oxidative phosphorylation could enhance nitrogen fixation in diazotrophs (Glick 2012). One study suggested that deletion of glgA gene, which encodes glycogen synthase, led to enhanced nitrogen fixation in legume-Rhizobia symbiosis (Marroqui et al. 2001). In this feature, the entire glgA gene has been deleted in order to abolish glycogen synthesis. The deletion of the glgA gene leads to increased levels of nitrogen fixation in both nitrogen-starvation and nitrogen-replete conditions.
GMR Campaign Utilizing Genetic Features
The microbes of the disclosure have been engineered to contain one or more of the aforementioned features. The overall goal of the GMR campaigns is to develop microbes that are capable of supplying all of the nitrogen needs of a corn plant throughout the entirety of a growing season. In
In
In addition to the historical GMR campaign for PBC6.1 depicted in
The mutations made to the PBC137 WT strain to incorporate the features F1-F3 are summarized in Table 33 below.
Case I: Current Gen1 Microbe Providing 17 Lbs of N from Strain 137-1036
Case II: Current Gen1 Microbe Strain 137-1036 after Activity Improved 5-Fold to Provide First Half of N Requirement
Case III: Microbe with Later Stage Colonization with 5× Improved Activity
Case IV: Combine Microbe from Case II and III into a Consortium, or Find and Remodel a Single Microbe that has the Depicted Colonization Profile and Stated Activity
As aforementioned in Example 8, the present disclosure provides a GMR campaign, which seeks to provide a farmer with a complete replacement for traditional synthetic fertilizer delivery. The “ecological sidedressing” discussed above in Example 7, which eliminates the need for a farmer to supply an in-season nitrogen application, is one step toward the ultimate goal of supplying a BNF product for cereal crops.
In order to remodel a microbe to be a successful BNF product for a cereal crop, it is paramount that the microbe colonizes a corn plant at a physiologically relevant time period of the corn's growth cycle, as well as colonizing said corn plant to a sufficient degree.
The inventors have surprisingly discovered a functional genus of microbes, which have a desirable spatial colonization pattern, which make this group of microbes particularly useful for GMR campaigns.
As can be seen in
Corn yields have increased significantly since the 1930s largely due to genetic improvement and better crop management. Grain yield is the product of the number of plants per acre, kernels per plant, and weight per kernel. Of the three components that make up grain yield, the number of plants per acre is the factor that the farmer has the most direct control over. Kernel number and kernel weight can be managed indirectly through proper fertility, weed, pest and disease management to optimize plant health, and weather also plays a major role. Currently the average U.S. corn planting density is just under 32,000 plants per acre and has increased 400 plants per acre per year since the 1960s.
However, ever-increasing planting populations are resulting in smaller and less expansive root systems available to acquire nutrients. Placing nutrients directly in the root zone at the right time using the correct source and rate increases the probability that roots will take up and utilize those nutrients.
Integrating this understanding of seeding rates, row spacing, and product placement with advanced fertility management practices such as applying the right source, right rate, right timing, and right place for nutrient management is critical to maximize grain yield and input efficiency at higher planting densities.
The microbes of the disclosure enable more densely planted corn crops, as the microbes live in intimate association with the plant (i.e. root surface) and provide the plant with a constant source of readily useable fixed atmospheric nitrogen.
The disclosure's teachings of a BNF source for cereal crops will provide farmers with a tool that enables more densely planted acreage, as all the plants in the field will have a ready source of nitrogen delivered to their root systems throughout the growing season. This type of nitrogen delivery will not only remove the need for an in-season “sidedressing” application of nitrogen, but will also enable the farmer to realize a higher yield per acre due to the increased planting density per acre.
The present inventors have further determined that the microbes of the disclosure are able to improve yield stability through a more consistent and uniform delivery of nitrogen. The microbes of the disclosure enable reduced infield variability of a corn crop exposed to said microbes, which translates into improved yield stability for the farmer.
Experimental Protocol for NDVI Field Trial
NDVI measurements were taken through satellite imaging about 1.5 months after corn planting to monitor the Normalized Difference Vegetation Index measurement. NDVI is calculated from the visible and near-infrared light reflected by vegetation. The remodeled microbe 137-1036 was applied to treat the corn, i.e. the remodeled Klebsiella variicola, which was deposited as NCMA 201712002 and can be found, inter alia, in Table 1.
With respect to
In the two plots that are shown in
Data on mean yield of corn from a field trial showing reduced in field variability for the field treated with the remodeled strain of the present disclosure (137-1036 strain) compared to untreated field is shown in Table 34 below.
The data in Table 34 is an average from 5 different locations comparing untreated field (check) and ProveN (137-1036 strain) treated field (PBM). The untreated/check fields were not treated with the microbes of the present disclosure and had exogenous N applied. The PBM fields were treated with the microbes of the present disclosure, but did not have sidedress applied. As shown in Table 34, the PBM field needed 35 lbs less side-dressing (first column); at the same time, the mean yield from the PBM field and untreated field was similar. The standard deviation for the mean yield obtained from the PBM field is considerably less than that of the check (16.5 vs 19.9 bushels per acre (bpa)). The lesser standard deviation for the PBM-treated field indicates more uniform vegetation and reduced heterogeneity compared to the control field which is consistent with the NDVI data shown in
The present inventors determined that over the course of evaluating the performance of the presently disclosed nitrogen producing microbes across a variety of soil types and conditions, the microbes consistently colonized corn roots and supplied N to corn plants, even in challenging soil types where traditional N fertilizer was not very effective. The present study evaluated 47 different soil types in variable weather conditions across 13 states in the U.S., which revealed the microbes thrived in all of the evaluated soil types and weather conditions. In this study, the soil with a high sand content was considered a “challenging” or “problematic” soil type as growers can lose nitrogen in these type of coils quickly whereas the soil with a low sand content was considered a “typical” or “non-problematic” soil type. The % sand content of 47 evaluated soil types was measured; it was observed that 5 of them had a very high sand content. Specifically, 5 of the 47 evaluated soil types had an average sand content of about 50.90% and were considered a “challenging” or “problematic” soil type and the remaining soil types with an average of about 26.64% sand content were considered a “typical” or “non-problematic” soil type. The individual sand content of the 5 challenging soil types is listed in Table 35.
Growers typically lose nitrogen in heavy rains and/or challenging soil types. The microbes exhibited strong performance in a variety of challenging soil types, as well as soil exposed to heavy rains.
The data from field trials showing improvement in corn yield for challenging soil types treated with the remodeled microbes of the present disclosure compared to the same soil type not treated with the remodel microbes is summarized in Table 35 below. The column “Pivot Yield” in Table 35 shows the yield from the challenging soil type fields treated with the remodeled strains of the present disclosure. For challenging soil types, the remodeled microbes conferred a ˜17 bushel per acre average against fields in comparable conditions using only chemical nitrogen fertilizer. This superior improvement in yield in challenging soil types and soil exposed to heavy rains is surprising because under typical soil and weather conditions, the application of the microbes exhibited a ˜7.7 bushel per acre advantage compared to fields without the microbes.
Utilizing the present microbes reduced the need for chemical fertilizer and delivers a return on investment to the growers who use the microbes, while decreasing the complexity and risk typically associated with chemical fertilizer use
As illustrated in Example 11 relating to reduced infield variability, as measured by NDVI, the current data of Example 12, demonstrating improved performance across a wide range of soil types, further illustrates that the microbe taught herein are able to lend yield predictability and reduce yield heterogeneity across a farmer's field.
The ability for a farmer to realize relatively homogeneous yield gains across their growing acreage, even in acres normally susceptible to low yields, is a dramatic step forward in the art. Farmers will now be able to more reliably predict yields and realize value on acreage that traditionally would be low performing.
In this example, Steps A-F described in Example 1 were used to generate several non-transgenic derivative strains of Klebsiella variicola Wild type (WT) strain, CI137. First, the WT strain, CI137, was isolated from a rhizosphere, characterized, and domesticated using the approaches described in steps A-C of Example 1.
Then using the approaches described in steps D-F of Example 1, the nitrogen fixation trait of CI137 was rationally improved without the use of transgenes. To test whether the nitrogen fixation trait of the WT strain can be improved, various genes involved in nitrogen fixation as described throughout this application were targeted to engineer non-intergeneric mutations, the engineered/remodeled microbes were analyzed for nitrogen fixation, and the engineering and the analytics steps were iterated to test whether further improvements can be made in the nitrogen fixation ability. Using this iterative approach, beneficial mutations were stacked to increase the nitrogen fixation ability.
Non-intergeneric mutations made through this iterative remodeling process to generate remodeled CI137 strains that showed improvement in nitrogen fixation are summarized in Table 36 below. The stepwise improvement in the nitrogen fixation trait of the remodeled strains is shown in
The feature sets indicated in Table 37 correspond to the Features List in
Soil microbes utilize plant-derived nutrient sources for growth as well as for fueling the energy intensive process of nitrogen fixation. While associative microbes in the rhizosphere rely on the nutrients exuded by the plant roots or the dead organic material found in soil, endophytic microbes have more direct access to the nutrients available inside the plant tissue, such as in the apoplast. To provide information to guide the selection of combinations and consortia of microorganisms that can make use of the nutrient sources plants produce, e.g., in a complementary fashion, the microbial preferences for nutrient sources was determined for five microorganisms. In addition, the nutrients exuded by corn plants or found inside the root tissues themselves were characterized. Then, the ability of certain strains to grow on the root slurries was determined.
Klebsiellavariicola, Kosakonia sacchari, Paraburkholderia tropica, Herbaspirillum seropedicae, and Herbaspirillum aquaticum were grown in Biolog plates to determine their carbon and nitrogen source preferences. This data is presented in
Preliminary data shows differences in their carbon and nitrogen source preferences, indicating that certain combinations of these microorganisms with one another, or with other microorganisms disclosed herein, may provide non-competitive sources of microorganisms for nitrogen fixation to a plant.
Furthermore, while Klebsiella variicola and Kosakonia sacchari can robustly grow under hypoxic or anaerobic conditions with sucrose and other sugar sources, Paraburkholderia tropica, Herbaspirillum seropedicae, and Herbaspirillum aquaticum strains cannot grow anaerobically due to inefficient fermentation pathways. These strains preferred organic acids under aerobic conditions and a mixture of sugar and organic acid under hypoxic conditions.
To develop a better understanding of the nutrient profile nitrogen-fixing microbes experience in planta in the associative and endophytic forms, two kinds of samples were collected for analysis:
1. Exudates from root slurries were collected by incubating corn plants of different ages in distilled, deionized water for 2 days in the dark.
2. Root slurry preparations were prepared by collecting root samples from corn plants of different ages and processing the root sample in equal weight of water using a blender and then filtering the final slurry. Root slurry samples were collected from low and high nitrogen treated plants at stages of 2, 4, 6, and 8 weeks growth.
Exudate analysis showed that the following sugars were found in the exudates collected from 4-6 week old plants: glucose>fructose>galactose>arabinose>xylose>sucrose.
In 1 week old plants, exudate included similar sugars, however, fructose was found 5-times more than glucose.
The time course study of the root slurries (as shown in
For the most part, the metabolic profile of exudates and root slurries were very similar. As such, for scalability, root slurries were used in subsequent experiments for testing growth of bacterial strains under in vitro conditions.
Biolector growth studies were performed for Klebsiellavariicola, Kosakonia sacchari, Metakosakonia intestini, and Paraburkholderia tropica under 2 different hypoxic conditions growing on root slurries as described in the foregoing sections. Based on this study, it was observed that the Paraburkholderia strain grew most optimally in root slurries, though growth was observed for all strains.
A metabolomics analysis was performed on these cultures after grown in root slurries as well as rich media (SOB) for 24 hours. See
Under hypoxic conditions, Paraburkholderia tropica could not produce butyrate, which is a fermentation byproduct that allows microbes to produce 1 extra ATP per sugar metabolized. This acts as an explanation for why Paraburkholderia does not perform as well as other strains under anaerobic conditions.
Overall, the results of the foregoing experiments demonstrate that the corn plant environment, whether around the roots or inside the roots, is rich and diverse in terms of carbon and nitrogen sources. However, this metabolic profile is dynamic and changes based on the plant treatments and the age of the plant. For this reason, the present disclosure particularly provides beneficial combinations of microbes that prefer different nutrient sources for growth and may complement each other non-competitively in nutrient source utilization.
Klebsiella variicola strain 137 (and its derivative strains) is present at moderate abundance levels during early developmental stages of corn, and subsequently declines. This is represented in
Through field experiments, four new bacterial strains were identified that are significantly more abundant than Klebsiella variicola either in an early corn vegetative developmental stage range (V4-V6) and/or a late one (V10-V12). In
These results demonstrate that microbes differ in their temporal occupation of plants. This difference can be leveraged to assemble microbial consortia comprising microbes that differ in terms of temporal occupation and that may not compete with one another, or may compete to a lesser extent, because of this difference.
Microbial localization is observed through fluorescence microscopy of plant roots and the surrounding matter. Observations indicate different spatial localizations of various microorganisms. For example, Klebsiella attach to root hairs, the surface of the zone of elongation and the root cap mucilage; Paenibacillus polymyxa is found mainly on the root surface; Herbaspirillum strains can be endophytic; and Paraburkolderia sticks mostly to root surfaces but can also colonize plant stems.
This diversity in the spatial localization of microorganisms demonstrates the viability of assembling microbial consortia of nitrogen-fixing bacteria that can occupy different spatial niches within/on/associated with a plant. This spatial diversity provides room for non-competition or lesser competition for resources, allowing the microbes to provide greater nitrogen to the plant in combination compared to combinations of microorganisms that occupy the same spatial niche.
Though Kosakonia sachhari (NCMA 201701001) and Klebsiella variicola (NCMA 201708001) occupy similar temporal (
PTA-126740 and PTA-126743 strains derepressed for nitrogen fixation were produced through non-intergeneric remodelling of the ancestral strains NCMA 201708001 and NCMA 201701001, respectively. Strain PTA-126740 was remodelled to decrease nitrogen assimilation through genetic engineering which deleted the glnD-UTase domain by removing 975 nucleotides after the start codon. Strain PTA-126743 was remodelled to decrease nitrogen assimilation through genetic engineering which deleted the coding sequence of glnD gene by removing all of the 2,676 nucleotides, including start and stop codons, and genetic engineering which deleted the first 1287 bp following the ATG start codon of the glnE gene, resulting in a GlnE protein lacking the AR domain but functionally expressing the ATase domain. Strain PTA-126743 was also remodelled to increase nitrogen fixation by retaining the first 30 base pairs and the last 83 base pairs, and removing the middle region of the nifL coding sequence, and inserting a promoter that natively drives rhtA expression in the organism.
To assess the robustness of these strains in different oxygen conditions, the strains were tested for ammonium excretion as described above, except that instead of being run in an anaerobic chamber, the assay was carried out in a hypoxic chamber at varying oxygen concentrations. As shown in
To analyze the ability of the consortia of microbes to provide nitrogen to corn plants, two protocols were used.
1. In the 20-ZEAMX-US403 mini-strip protocol, the PTA-126743/PTA-126740 combination was compared with an untreated control (UTC), and with both PTA-126743 and PTA-126740 as separate single entries. This protocol consisted of replicated plots of 8 corn rows by 100 feet at 25 locations through the Midwest corn growing reasons. Four of these locations failed a quality control and were not used in the analysis.
2. In the second protocol, the 20-ZEAMX-US501 on-farm protocol, the PTA-126743/PTA-126740 combination was compared with untreated control (UTC) and with PTA-126740 as a single separate entry. This protocol consisted of 20 unreplicated locations at real working farms. Plot size was variable.
Each plot in both protocols was sampled for whole plant nitrogen and nitrogen percent at the reproductive growth stage of corn, referred to as VT. From each plot, 3 entire plants were harvested and shipped to a tissue laboratory for processing. At the lab, they were dry and weighed. The nitrogen content subsample of the dried material was measured. This provided a measurement at each plot of both the nitrogen content per plant, N(g), (
As shown in
The Bayesian model used produced a posterior distribution, allowing comparison of the combination strain with each of the entries. These comparisons are shown in Table 38 and range between an 80.2% and a 99.6% that the combination strain is better than the individual strain, depending on the protocol and the measurement.
Table 39 shows the results of Examples 14-18 for a selection of illustrative microbes.
Klebsiella variicola
Kosakonia sacchari
Paraburkholderia
tropica
Herbaspirillum
seropedicae
Herbaspirillum
aquaticum
Paenibacillus
polymyxa
saccari
variicola
Metakosakonia intestini
Paraburkholderia tropica
Paenibacillus polymyxa
Herbaspirillum aquaticum
Notwithstanding the appended claims, the disclosure sets forth the following numbered embodiments:
1. A synthetic composition of microbes functionally optimized for nitrogen fixation and targeted delivery to a host plant, comprising: a consortium of at least two microbial species that differ in functional attributes along at least one of the following dimensions:
a) nutrient utilization;
b) temporal occupation;
c) oxygen adaptability; and
d) spatial occupation.
2. The composition of embodiment 1, wherein the consortium comprises at least two microbial species selected from the group consisting of Klebsiellavariicola, Kosakonia sacchari, Paraburkholderia tropica, Herbaspirillum seropedicae, Herbaspirillum aquaticum, and Paenibacillus polymyxa.
3. The composition of any one of embodiments 1-2, wherein the consortium comprises at least two microbial species that differ in terms of nutrient utilization.
4. The composition of any one of embodiments 1-3, wherein the difference in nutrient utilization comprises a difference in nutrient utilization in growth and/or nutrient utilization assays in one or more media comprising at least two different nutrient sources.
5. The composition of any one of embodiments 1-4, wherein the consortium comprises at least two microbial species that differ in terms of nutrient utilization, wherein a nutrient they utilize differently is a carbon source selected from a simple carbohydrate, complex carbohydrate, organic acid, amino acid, and carboxylic acid.
6. The composition of any one of embodiments 1-5, wherein the consortium comprises at least two microbial species that differ in terms of nutrient utilization, wherein a nutrient they utilize differently is a nitrogen source selected from an amino acid, amine, amide, and peptide.
7. The composition of any one of embodiments 1-6, wherein the consortium comprises at least two microbial species that differ in terms of nutrient utilization, wherein they differ in the utilization of nutrients available in a plant rhizosphere, surface plant tissue region, and/or endophytic plant tissue region.
8. The composition of any one of embodiments 1-7, wherein the consortium comprises at least two microbial species that differ in terms of nutrient utilization, wherein they differ in the utilization of nutrients available in the corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
9. The composition of any one of embodiments 1-8, wherein the consortium comprises at least two microbial species that differ in terms of nutrient utilization, wherein they differ in the utilization of a simple carbohydrate, complex carbohydrate, organic acid, or carboxylic acid and/or an amino acid, amine, amide, or peptide available in the corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
10. The composition of any one of embodiments 1-9, wherein the consortium comprises at least two microbial species that differ in terms of nutrient utilization, and wherein the different nutrient utilization is such that the at least two microbial species could co-exist non-competitively in a plant rhizosphere, surface plant tissue region, and/or endophytic plant tissue region.
11. The composition of any one of embodiments 1-10, wherein the consortium comprises at least two microbial species that differ in terms of nutrient utilization, and wherein the different nutrient utilization is such that the at least two microbial species could co-exist non-competitively in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
12. The composition of any one of embodiments 1-11, wherein the consortium comprises at least two microbial species that differ in terms of temporal occupation.
13. The composition of any one of embodiments 1-12, wherein the difference in temporal occupation comprises a difference in nitrogen fixation at different time points in a plant growing cycle.
14. The composition of any one of embodiments 1-13, wherein the consortium comprises at least two microbial species that differ in terms of temporal occupation, wherein the peak nitrogen fixation time period of the at least two microbial species differs by at least 2 weeks, at least 3 weeks, at least 4 weeks, at least 5 weeks, at least 6 weeks, at least 7 weeks, at least 8 weeks, at least 9 weeks, at least 10 weeks, at least 11 weeks, or at least 12 weeks in the average growing cycle of a given plant.
15. The composition of any one of embodiments 1-14, wherein the consortium comprises at least two microbial species that differ in terms of temporal occupation, wherein the peak nitrogen fixation time period of the at least two microbial species differs by at least 2 weeks in the average growing cycle of a given plant.
16. The composition of any one of embodiments 1-15, wherein the consortium comprises at least two microbial species that differ in terms of temporal occupation, wherein the peak nitrogen fixation time period of the at least two microbial species differs by at least 1 month, at least 2 months, at least 3 months, at least 4 months, at least 5 months, at least 6 months, at least 7 months, at least 8 months, at least 9 months, or at least 10 months in the average growing cycle of a given plant.
17. The composition of any one of embodiments 1-16, wherein the consortium comprises at least two microbial species that differ in terms of temporal occupation, wherein the peak nitrogen fixation time period of the at least two microbial species differs by at least 1 month in the average growing cycle of a given plant.
18. The composition of any one of embodiments 1-17, wherein the consortium comprises at least two microbial species that differ in terms of temporal occupation, and wherein the different temporal occupation is such that the at least two microbial species could non-competitively fix nitrogen for a given plant at different time periods of the plant's growing cycle.
19. The composition of any one of embodiments 1-18, wherein the consortium comprises at least two microbial species that differ in terms of temporal occupation in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
20. The composition of any one of embodiments 1-19, wherein the consortium comprises at least two microbial species that differ in terms of temporal occupation in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn, and wherein the peak nitrogen fixation time period of the at least two microbial species differs by at least one stage in the growing cycle of corn.
21. The composition of any one of embodiments 1-20, wherein the consortium comprises at least two microbial species that differ in terms of temporal occupation in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn, and wherein the peak nitrogen fixation time periods of the at least two microbial species occurs during a different stage, or series of two or more stages, of the corn growing cycle selected from VE, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13, V14, V15, V16, VT, R1, R2, R3, R4, R5, and R6.
22. The composition of any one of embodiments 1-21, wherein the consortium comprises at least two microbial species that differ in terms of temporal occupation in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn, and wherein the peak nitrogen fixation time periods of the at least two microbial species occur during different periods of the corn growing cycle selected from V4-V6, V6-V10, and V10-V12.
23. The composition of any one of embodiments 1-22, wherein the consortium comprises at least two microbial species that differ in terms of temporal occupation in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn, and wherein the different temporal occupation is such that the at least two microbial species could non-competitively fix nitrogen at different time periods of the corn growing cycle.
24. The composition of any one of embodiments 1-23, wherein the consortium comprises at least two microbial species that differ in terms of oxygen adaptability.
25. The composition of any one of embodiments 1-24, wherein the difference in terms of oxygen adaptability comprises a difference in nitrogen fixation under different oxygenation conditions.
26. The composition of any one of embodiments 1-25, wherein the consortium comprises at least two microbial species that differ in terms of oxygen adaptability, and wherein the at least two microbial species exhibit optimal nitrogen fixation under different conditions, or different combinations of conditions, selected from hypoxic, anaerobic, aerobic, and microaerobic conditions.
27. The composition of any one of embodiments 1-26, wherein the consortium comprises at least two microbial species that differ in terms of spatial occupation.
28. The composition of any one of embodiments 1-27, wherein the difference in spatial occupation comprises a difference in colonization of the species in the rhizosphere, surface plant tissue region, and/or endophytic plant tissue region of a given plant.
29. The composition of any one of embodiments 1-28, wherein the consortium comprises at least two microbial species that differ in terms of spatial occupation, such that the plurality of microbes of one species comprised by the consortium occupies a different location on the plant than a plurality of microbes of another species.
30. The composition of any one of embodiments 1-29, wherein the consortium comprises at least two microbial species that differ in terms of spatial occupation of one or more of the endorhizosphere, the rhizoplane, and the ectorhizosphere.
31. The composition of any one of embodiments 1-30, wherein the consortium comprises at least two microbial species that differ in terms of spatial occupation of the endorhizosphere.
32. The composition of any one of embodiments 1-31, wherein the consortium comprises at least two microbial species that differ in terms of spatial occupation of the rhizoplane.
33. The composition of any one of embodiments 1-32, wherein the consortium comprises at least two microbial species that differ in terms of spatial occupation of the ectorhizosphere.
34. The composition of any one of embodiments 1-33, wherein the consortium comprises at least two microbial species that differ in terms of spatial occupation of one or more of the root junctions, zone of elongation, root cap, root mucilage, root hairs, root surface, and plant stems of a given plant.
35. The composition of any one of embodiments 1-34, wherein the consortium comprises at least two microbial species that differ in terms of spatial occupation of one or more of the root junctions, zone of elongation, root cap, root mucilage, root hairs, root surface, and stems of corn.
36. The composition of any one of embodiments 1-35, wherein the consortium comprises at least two microbial species that differ in terms of spatial occupation in the corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
37. The composition of any one of embodiments 1-36, wherein the consortium comprises at least two microbial species that differ in terms of spatial occupation, and wherein the different spatial occupation is such that the at least two microbial species could co-exist non-competitively in a plant's rhizosphere, surface plant tissue region, and/or endophytic plant tissue region.
38. The composition of any one of embodiments 1-37, wherein the consortium comprises at least two microbial species that differ in terms of spatial occupation, and wherein the different spatial occupation is such that the at least two microbial species could co-exist non-competitively in a corn rhizosphere, surface tissue region of corn, and/or endophytic tissue region of corn.
39. A composition, comprising: a consortium of at least two microbial species selected from the group consisting of Klebsiellavariicola, Kosakonia sacchari, Paraburkholderia tropica, Herbaspirillum seropedicae, Herbaspirillum aquaticum, and Paenibacillus polymyxa.
40. The composition of any one of embodiments 1-39, wherein at least one of the microbial species comprises heterologous genetic material, and wherein the microbial species has improved nitrogen fixation relative to the microbial species without the heterologous genetic material.
41. The composition of any one of embodiments 1-40, wherein at least one of the microbial species lacks genetic material, and wherein the microbial species lacking the genetic material has improved nitrogen fixation relative to the microbial species comprising the genetic material.
42. The composition of any one of embodiments 1-41, wherein at least one microbial species is genetically engineered to fix atmospheric nitrogen and provide such to a host plant.
43. The composition of any one of embodiments 1-42, wherein at least one microbial species is a remodeled microbe.
44. The composition of any one of embodiments 1-43, wherein at least one microbial species is a transgenic microbial species.
45. The composition of any one of embodiments 1-44, wherein at least one microbial species comprises a non-intergeneric genomic modification.
46. The composition of any one of embodiments 1-45, wherein at least one microbial species is a non-intergeneric remodeled microbial species capable of fixing atmospheric nitrogen in the presence of exogenous nitrogen.
47. The composition of any one of embodiments 1-46, wherein at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into at least one gene, or non-coding polynucleotide, of the nitrogen fixation or assimilation genetic regulatory network.
48. The composition of any one of embodiments 1-47, wherein at least one microbial species is a non-intergeneric remodeled microbial species comprising an introduced control sequence operably linked to at least one gene of the nitrogen fixation or assimilation genetic regulatory network.
49. The composition of any one of embodiments 1-48, wherein at least one microbial species is a non-intergeneric remodeled microbial species comprising a heterologous promoter operably linked to at least one gene of the nitrogen fixation or assimilation genetic regulatory network.
50. The composition of any one of embodiments 1-49, wherein at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into a gene selected from the group consisting of: nifA, nifL, ntrB, ntrC, polynucleotide encoding glutamine synthetase, glnA, glnB, glnK, drat, amtB, polynucleotide encoding glutaminase, glnD, glnE, nifJ, nifH, nifD, nifK, nifY, nifE, nifN, nifU, nifS, nifV, nifW, nifZ, nifM, nifF, nifB, nifQ, a gene associated with biosynthesis of a nitrogenase enzyme, and combinations thereof.
51. The composition of any one of embodiments 1-50, wherein at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into at least one gene, or non-coding polynucleotide, of the nitrogen fixation or assimilation genetic regulatory network that results in one or more of: increased expression or activity of NifA or glutaminase; decreased expression or activity of NifL, NtrB, glutamine synthetase, GlnB, GlnK, DraT, AmtB; decreased adenylyl-removing activity of GlnE; or decreased uridylyl-removing activity of GlnD.
52. The composition of any one of embodiments 1-51, wherein at least one microbial species is a non-intergeneric remodeled microbial species comprising a mutated nifL gene that has been altered to comprise a heterologous promoter inserted into said nifL gene.
53. The composition of any one of embodiments 1-52, wherein at least one microbial species is a non-intergeneric remodeled microbial species comprising a mutated glnE gene that results in a truncated GlnE protein lacking an adenylyl-removing (AR) domain.
54. The composition of any one of embodiments 1-53, wherein at least one microbial species is a non-intergeneric remodeled microbial species comprising a mutated amtB gene that results in the lack of expression of said amtB gene.
55. The composition of any one of embodiments 1-54, wherein at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one of: a mutated nifL gene that has been altered to comprise a heterologous promoter inserted into said nifL gene; a mutated glnE gene that results in a truncated GlnE protein lacking an adenylyl-removing (AR) domain; a mutated amtB gene that results in the lack of expression of said amtB gene; a mutated glnD gene that results in a truncated GlnD protein lacking a uridyl-transferase domain or lack of expression of said glnD gene, and combinations thereof.
56. The composition of any one of embodiments 1-55, wherein at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into genes involved in a pathway selected from the group consisting of: exopolysaccharide production, endo-polygalaturonase production, trehalose production, and glutamine conversion.
57. The composition of any one of embodiments 1-56, wherein at least one microbial species is a non-intergeneric remodeled microbial species comprising at least one genetic variation introduced into genes selected from the group consisting of: bcsii, bcsiii, yjbE, fhaB, pehA, otsB, treZ, glsA2, and combinations thereof.
58. The composition of any one of embodiments 1-57, wherein at least one microbial species is a non-intergeneric remodeled bacterium selected from: Paenibacillus polymyxa, Paraburkholderia tropica, Herbaspirillum aquaticum, Metakosakonia intestini, Rahnella aquatilis, Klebsiella variicola, Achromobacter spiritinus, Achromobacter marplatensis, Microbacterium murale, Kluyvera intermedia, Kosakonia pseudosacchari, Enterobacter sp., Azospirillum lipoferum, Kosakonia sacchari, and combinations thereof.
59. The composition of any one of embodiments 1-58, wherein at least one microbial species is a non-intergeneric remodeled bacterium selected from: a bacteria deposited as ATCC PTA-126575, a bacteria deposited as ATCC PTA-126576, a bacteria deposited as ATCC PTA-126577, a bacteria deposited as ATCC PTA-126578, a bacteria deposited as ATCC PTA-126579, a bacteria deposited as ATCC PTA-126580, a bacteria deposited as ATCC PTA-126584, a bacteria deposited as ATCC PTA-126586, a bacteria deposited as ATCC PTA-126587, a bacteria deposited as ATCC PTA-126588, a bacteria deposited as NCMA 201701002, a bacteria deposited as NCMA 201708004, a bacteria deposited as NCMA 201708003, a bacteria deposited as NCMA 201708002, a bacteria deposited as NCMA 201712001, a bacteria deposited as NCMA 201712002, a bacteria deposited as PTA-126740, a bacteria deposited as PTA-126743, and combinations thereof.
60. The composition of any one of embodiments 1-59, wherein at least one microbial species is a non-intergeneric remodeled bacterium comprising a nucleic acid sequence that shares at least about 90%, 95%, or 99% sequence identity to a nucleic acid sequence selected from SEQ ID NOs: 177-260, 296-303, and 458-469.
61. The composition of any one of embodiments 1-60, wherein at least one microbial species is a non-intergeneric remodeled bacterium comprising a nucleic acid sequence selected from SEQ ID NOs: 177-260, 296-303, and 458-469.
62. A method of using a composition according to any one of embodiments 1-61.
63. The method of embodiment 62, wherein the method is for improving the nitrogen delivery to a plant.
64. The method of any one of embodiments 62-63, wherein the method is for improving the quantity of nitrogen delivered to a plant.
65. The method of any one of embodiments 62-64, wherein the method is for improving the quantity of nitrogen delivered to a plant at a specific time during the plant's growing cycle.
66. The method of any one of embodiments 62-65, wherein the method is for improving the overall quantity of nitrogen delivered to a plant over the entire course of the plant's growing cycle.
67. The method of any one of embodiments 62-66, wherein the method comprises applying the composition to a plant.
68. The method of any one of embodiments 62-67, wherein the method comprises applying the composition to a plant by applying the composition to the plant seeds prior to planting.
69. The method of any one of embodiments 62-68, wherein the method comprises applying the composition to a plant by applying the composition to the plant seeds or the plant itself during or after planting.
70. The method of any one of embodiments 62-69, wherein the method comprises applying the composition to a plant, and wherein the method results in improved plant yield compared to a plant not comprising the composition.
71. The method of any one of embodiments 62-70, wherein the method comprises applying the composition to a plant, and wherein the method results in improved plant yield compared to a plant not comprising a nitrogenous fertilizer.
72. The method of any one of embodiments 62-71, wherein the method comprises applying the composition to a plant, and wherein the method results in improved plant yield compared to a plant not comprising the composition.
73. The method of any one of embodiments 62-72, wherein the method comprises applying the composition to a plant, and wherein the method reduces the need for a synthetic source of nitrogenous fertilizer.
74. The method of any one of embodiments 62-73, wherein the method comprises applying the composition to a plant, and wherein the plant is corn.
75. A method of creating a synthetic composition of microbes functionally optimized for nitrogen fixation and targeted delivery to a host plant, comprising the steps of:
While preferred embodiments of the present disclosure have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the disclosure. It should be understood that various alternatives to the embodiments of the disclosure described herein may be employed in practicing the disclosure. It is intended that the following Claims define the scope of the disclosure and that methods and structures within the scope of these claims and their equivalents be covered thereby.
All references, articles, publications, patents, patent publications, and patent applications cited herein are incorporated by reference in their entireties for all purposes. However, mention of any reference, article, publication, patent, patent publication, and patent application cited herein is not, and should not be taken as, an acknowledgment or any form of suggestion that they constitute valid prior art or form part of the common general knowledge in any country in the world. Further, U.S. Pat. No. 9,975,817, issued on May 22, 2018, and entitled: Methods and Compositions for Improving Plant Traits, is hereby incorporated by reference. Further, PCT/US2018/013671, filed Jan. 12, 2018, and entitled: Methods and Compositions for Improving Plant Traits, is hereby incorporated by reference.
This application claims the benefit of priority to U.S. Provisional Application No. 62/960,655, filed on Jan. 13, 2020. This application also claims the benefit of priority to U.S. Provisional Application No. 63/019,247 filed May 1, 2020. This application also claims the benefit of priority to International Application No. PCT/US2020/031201, filed May 1, 2020. Each of these applications is hereby incorporated by reference in its entirety for all purposes.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2021/013120 | 1/12/2021 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63019247 | May 2020 | US | |
| 62960655 | Jan 2020 | US |
