Patent Application
20210171971
The official copy of the sequence listing is submitted electronically via EFS-Web as an ASCII formatted sequence listing with a file named 7841_ST25.txt created on Dec. 7, 2018 and having a size of 1897 kilobytes and is filed concurrently with the specification. The sequence listing comprised in this ASCII formatted document is part of the specification and is herein incorporated by reference in its entirety.
This disclosure relates to compositions and methods for improving yield in plants.
Global demand and consumption of agricultural crops is increasing at a rapid pace. Accordingly, there is a need to develop new compositions and methods to increase yield in plants. This invention provides such compositions and methods.
Provided herein are polynucleotides encoding a polypeptide comprising an amino acid sequence that is at least 90%, 92%, 95%, 96%, 97%, 98%, 99% or 100% identical to a full length amino acid sequence selected from the group consisting of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573. Provided herein are polynucleotides that are at least 85% identical to a polynucleotide sequence selected from the group consisting of SEQ ID NOS: 12-22, 32-39, and 300-561.
Provided herein are SEQ ID NOS: 1-11 (Interactor Polypeptides); SEQ ID NOS: 12-22 (polynucleotides encoding Interactor Polypeptides); SEQ ID NOS: 23-31, 563, and 567-572 (Direct Target Polypeptides); SEQ ID NOS: 32-39, 564, and 573-579 (polynucleotides encoding Direct Target Polypeptides); SEQ ID NOS: 40-299 (Differentially Expressed Polypeptides); SEQ ID NOS: 300-561 (polynucleotides encoding Differentially Expressed Polupeptides); SEQ ID NOS: 223-284 (Down Regulated Polypeptides); SEQ ID NOS: 485-547 (polynucleotides encoding Down Regulated Polypeptides).
Also provided are recombinant DNA constructs comprising a regulatory element operably linked to a polynucleotide encoding a polypeptide comprising an amino acid sequence that is at least 80% to 100% identical to a full length amino acid sequence selected from the group consisting of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573. In certain embodiments the regulatory element is a heterologous promoter.
Also provided are recombinant DNA constructs comprising a genetic element that suppresses or reduces expression of a polynucleotide encoding a polypeptide comprising an amino acid sequence that is at least 80% to about 100% identical to an amino acid sequence selected from the group consisting of SEQ ID NOS: 223-284 (Down Regulated Polypeptides). In certain embodiments the reduction in expression is performed by RNAi mechanism.
Provided are plant cells, plants, and seeds comprising the polynucleotide encoding a polypeptide or the recombinant DNA construct comprising a regulatory element operably linked to the polynucleotide encoding a polypeptide. In certain embodiments, the regulatory element is a heterologous promoter. In certain embodiments, the plant and/or seed is from a monocot plant. In certain embodiments, the plant is a monocot plant. In certain embodiments, the monocot plant is maize.
Further provided are plant cells, plants, and seeds comprising a targeted genetic modification at a genomic locus that encodes a polypeptide comprising an amino acid sequence that is at least 80% to about 100% identical to a full length amino acid sequence selected from the group consisting of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573, wherein the genetic modification increases the level and/or activity of the encoded polypeptide. In certain embodiments, the genetic modification is selected from the group consisting of an insertion, deletion, single nucleotide polymorphism (SNP), and a polynucleotide modification. In certain embodiments the targeted genetic modification is present in (a) the coding region; (b) a non-coding region; (c) a regulatory sequence; (d) an untranslated region; or (e) any combination of (a)-(d) of the genomic locus that encodes the polypeptide. In certain embodiments, the plant and/or seed is from a monocot plant. In certain embodiments, the plant is a monocot plant. In certain embodiments, the monocot plant is maize.
Provided are methods for increasing yield in a plant by expressing in a regenerable plant cell a recombinant DNA construct comprising a regulatory element operably linked to a polynucleotide encoding a polypeptide comprising an amino acid sequence that is at least 80% to about 100% identical to an amino acid sequence selected from the group consisting of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573; and generating the plant, wherein the plant comprises in its genome the recombinant DNA construct. In certain embodiments, the regulatory element is a heterologous promoter. In certain embodiments, the plant is a monocot plant. In certain embodiments, the monocot plant is maize. In certain embodiments, the yield is grain yield.
Further provided are methods for increasing yield in a plant by introducing in a regenerable plant cell a targeted genetic modification at a genomic locus that encodes a polypeptide comprising an amino acid sequence that is at least 80% identical to an amino acid sequence selected from the group consisting of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573; and generating the plant, wherein the level and/or activity of the encoded polypeptide is increased in the plant. In certain embodiments, the genetic modification is introduced using a genome modification technique selected from the group consisting of a polynucleotide-guided endonuclease, CRISPR-Cas endonucleases, base editing deaminases, a zinc finger nuclease, a transcription activator-like effector nuclease (TALEN), an engineered site-specific meganucleases, or an Argonaute. In certain embodiments, the targeted genetic modification is present in (a) the coding region; (b) a non-coding region; (c) a regulatory sequence; (d) an untranslated region; or (e) any combination of (a)-(d) of the genomic locus that encodes the polypeptide. In certain embodiments, the plant cell is from a monocot plant. In certain embodiments, the monocot plant is maize. In certain embodiments, the yield is grain yield.
Provided are methods for increasing photosynthetic activity in a plant by expressing in a regenerable plant cell a recombinant DNA construct comprising a regulatory element operably linked to a polynucleotide encoding a polypeptide comprising an amino acid sequence that is at least 80% identical to an amino acid sequence selected from the group consisting of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573; and generating the plant, wherein the plant comprises in its genome the recombinant DNA construct. In certain embodiments, the regulatory element is a heterologous promoter. In certain embodiments, the plant is a monocot plant. In certain embodiments, the monocot plant is maize.
Also provided are methods for increasing photosynthetic activity in a plant by introducing in a regenerable plant cell a targeted genetic modification at a genomic locus that encodes a polypeptide comprising an amino acid sequence that is at least 80% identical to an amino acid sequence selected from the group consisting of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573; and generating the plant, wherein the level and/or activity of the encoded polypeptide is increased in the plant. In certain embodiments, the genetic modification is introduced using a genome modification technique selected from the group consisting of a polynucleotide-guided endonuclease, CRISPR-Cas endonucleases, base editing deaminases, a zinc finger nuclease, a transcription activator-like effector nuclease (TALEN), an engineered site-specific meganucleases, or an Argonaute. In certain embodiments, the targeted genetic modification is present in (a) the coding region; (b) a non-coding region; (c) a regulatory sequence; (d) an untranslated region; or (e) any combination of (a)-(d) of the genomic locus that encodes the polypeptide. In certain embodiments, the plant cell is from a monocot plant. In certain embodiments, the monocot plant is maize.
The disclosure can be more fully understood from the following detailed description and the accompanying drawings and Sequence Listing, which form a part of this application.
The sequence descriptions and sequence listing attached hereto comply with the rules governing nucleotide and amino acid sequence disclosures in patent applications as set forth in 37 C.F.R. §§ 1.821 and 1.825. The sequence descriptions comprise the three letter codes for amino acids as defined in 37 C.F.R. §§ 1.821 and 1.825, which are incorporated herein by reference.
mays MADS14; ZmM5)
mays MADS6)
mays MADS7)
mays MADS24)
mays splicing factor 2)
Zea mays mRNA splicing factor
The present disclosure provides polynucleotides encoding polypeptides. Accordingly, as used herein “polypeptide,” “protein,” or the like, refers to a protein represented by a SEQ ID NO.
One aspect of the disclosure provides a polynucleotide encoding a polypeptide comprising an amino acid sequence that is at least 80-99% identical to the amino acid sequence of any one of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573).
As used herein “encoding,” “encoded,” or the like, with respect to a specified nucleic acid, is meant comprising the information for translation into the specified protein. A nucleic acid encoding a protein may comprise non-translated sequences (e.g., introns) within translated regions of the nucleic acid, or may lack such intervening non-translated sequences (e.g., as in cDNA). The information by which a protein is encoded is specified by the use of codons. Typically, the amino acid sequence is encoded by the nucleic acid using the “universal” genetic code. However, variants of the universal code, such as is present in some plant, animal and fungal mitochondria, the bacterium Mycoplasma capricolum (Yamao, et al., (1985) Proc. Natl. Acad. Sci. USA 82:2306-9) or the ciliate Macronucleus, may be used when the nucleic acid is expressed using these organisms.
When the nucleic acid is prepared or altered synthetically, advantage can be taken of known codon preferences of the intended host where the nucleic acid is to be expressed. For example, although nucleic acid sequences of the present invention may be expressed in both monocotyledonous and dicotyledonous plant species, sequences can be modified to account for the specific codon preferences and GC content preferences of monocotyledonous plants or dicotyledonous plants as these preferences have been shown to differ (Murray, et al., (1989) Nucleic Acids Res. 17:477-98).
As used herein, “polynucleotide” includes reference to a deoxyribopolynucleotide, ribopolynucleotide or analogs thereof that have the essential nature of a natural ribonucleotide in that they hybridize, under stringent hybridization conditions, to substantially the same nucleotide sequence as naturally occurring nucleotides and/or allow translation into the same amino acid(s) as the naturally occurring nucleotide(s). A polynucleotide can be full-length or a subsequence of a structural or regulatory gene. Unless otherwise indicated, the term includes reference to the specified sequence as well as the complementary sequence thereof. Thus, DNAs or RNAs with backbones modified for stability or for other reasons are “polynucleotides” as that term is intended herein. Moreover, DNAs or RNAs comprising unusual bases, such as inosine, or modified bases, such as tritylated bases, to name just two examples, are polynucleotides as the term is used herein. It will be appreciated that a great variety of modifications have been made to DNA and RNA that serve many useful purposes known to those of skill in the art. The term polynucleotide as it is employed herein embraces such chemically, enzymatically or metabolically modified forms of polynucleotides, as well as the chemical forms of DNA and RNA characteristic of viruses and cells, including inter alia, simple and complex cells.
The terms “polypeptide,” “peptide” and “protein” are used interchangeably herein to refer to a polymer of amino acid residues. The terms apply to amino acid polymers in which one or more amino acid residues is an artificial chemical analogue of a corresponding naturally occurring amino acid, as well as to naturally occurring amino acid polymers.
As used herein, “sequence identity” or “identity” in the context of two nucleic acid or polypeptide sequences includes reference to the residues in the two sequences, which are the same when aligned for maximum correspondence over a specified comparison window. When percentage of sequence identity is used in reference to proteins it is recognized that residue positions which are not identical often differ by conservative amino acid substitutions, where amino acid residues are substituted for other amino acid residues with similar chemical properties (e.g., charge or hydrophobicity) and therefore do not change the functional properties of the molecule. Where sequences differ in conservative substitutions, the percent sequence identity may be adjusted upwards to correct for the conservative nature of the substitution. Sequences, which differ by such conservative substitutions, are said to have “sequence similarity” or “similarity.” Means for making this adjustment are well known to those of skill in the art. Typically, this involves scoring a conservative substitution as a partial rather than a full mismatch, thereby increasing the percentage sequence identity. Thus, for example, where an identical amino acid is given a score of 1 and a non-conservative substitution is given a score of zero, a conservative substitution is given a score between zero and 1. The scoring of conservative substitutions is calculated, e.g., according to the algorithm of Meyers and Miller, (1988) Computer Applic. Biol. Sci. 4:11-17, e.g., as implemented in the program PC/GENE (Intelligenetics, Mountain View, Calif., USA).
As used herein, “percentage of sequence identity” means the value determined by comparing two optimally aligned sequences over a comparison window, wherein the portion of the polynucleotide sequence in the comparison window may comprise additions or deletions (i.e., gaps) as compared to the reference sequence (which does not comprise additions or deletions) for optimal alignment of the two sequences. The percentage is calculated by determining the number of positions at which the identical nucleic acid base or amino acid residue occurs in both sequences to yield the number of matched positions, dividing the number of matched positions by the total number of positions in the window of comparison and multiplying the result by 100 to yield the percentage of sequence identity.
As used herein, “reference sequence” is a defined sequence used as a basis for sequence comparison. A reference sequence may be a subset or the entirety of a specified sequence; for example, as a segment of a full-length cDNA or gene sequence or the complete cDNA or gene sequence.
As used herein, “comparison window” means includes reference to a contiguous and specified segment of a polynucleotide sequence, wherein the polynucleotide sequence may be compared to a reference sequence and wherein the portion of the polynucleotide sequence in the comparison window may comprise additions or deletions (i.e., gaps) compared to the reference sequence (which does not comprise additions or deletions) for optimal alignment of the two sequences. Generally, the comparison window is at least 20 contiguous nucleotides in length, and optionally can be 30, 40, 50, 100 or longer. Those of skill in the art understand that to avoid a high similarity to a reference sequence due to inclusion of gaps in the polynucleotide sequence a gap penalty is typically introduced and is subtracted from the number of matches.
Methods of alignment of nucleotide and amino acid sequences for comparison are well known in the art. The local homology algorithm (BESTFIT) of Smith and Waterman, (1981) Adv. Appl. Math 2:482, may conduct optimal alignment of sequences for comparison; by the homology alignment algorithm (GAP) of Needleman and Wunsch, (1970) J. Mol. Biol. 48:443-53; by the search for similarity method (Tfasta and Fasta) of Pearson and Lipman, (1988) Proc. Natl. Acad. Sci. USA 85:2444; by computerized implementations of these algorithms, including, but not limited to: CLUSTAL in the PC/Gene program by Intelligenetics, Mountain View, California, GAP, BESTFIT, BLAST, FASTA and TFASTA in the Wisconsin Genetics Software Package®, Version 8 (available from Genetics Computer Group (GCG® programs (Accelrys, Inc., San Diego, Calif.)). The CLUSTAL program is well described by Higgins and Sharp, (1988) Gene 73:237 44; Higgins and Sharp, (1989) CABIOS 5:151 3; Corpet, et al., (1988) Nucleic Acids Res. 16:10881-90; Huang, et al., (1992) Computer Applications in the Biosciences 8:155-65, and Pearson, et al., (1994) Meth. Mol. Biol. 24:307-31. The preferred program to use for optimal global alignment of multiple sequences is PileUp (Feng and Doolittle, (1987) J. Mol. Evol., 25:351-60 which is similar to the method described by Higgins and Sharp, (1989) CABIOS 5:151-53 and hereby incorporated by reference). The BLAST family of programs which can be used for database similarity searches includes: BLASTN for nucleotide query sequences against nucleotide database sequences; BLASTX for nucleotide query sequences against protein database sequences; BLASTP for protein query sequences against protein database sequences; TBLASTN for protein query sequences against nucleotide database sequences; and TBLASTX for nucleotide query sequences against nucleotide database sequences. See, CURRENT PROTOCOLS IN MOLECULAR BIOLOGY, Chapter 19, Ausubel, et al., eds., Greene Publishing and Wiley-Interscience, New York (1995).
GAP uses the algorithm of Needleman and Wunsch, supra, to find the alignment of two complete sequences that maximizes the number of matches and minimizes the number of gaps. GAP considers all possible alignments and gap positions and creates the alignment with the largest number of matched bases and the fewest gaps. It allows for the provision of a gap creation penalty and a gap extension penalty in units of matched bases. GAP must make a profit of gap creation penalty number of matches for each gap it inserts. If a gap extension penalty greater than zero is chosen, GAP must, in addition, make a profit for each gap inserted of the length of the gap times the gap extension penalty. Default gap creation penalty values and gap extension penalty values in Version 10 of the Wisconsin Genetics Software Package® are 8 and 2, respectively. The gap creation and gap extension penalties can be expressed as an integer selected from the group of integers consisting of from 0 to 100. Thus, for example, the gap creation and gap extension penalties can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 40, 50 or greater.
GAP presents one member of the family of best alignments. There may be many members of this family, but no other member has a better quality. GAP displays four figures of merit for alignments: Quality, Ratio, Identity and Similarity. The Quality is the metric maximized in order to align the sequences. Ratio is the quality divided by the number of bases in the shorter segment. Percent Identity is the percent of the symbols that actually match. Percent Similarity is the percent of the symbols that are similar. Symbols that are across from gaps are ignored. A similarity is scored when the scoring matrix value for a pair of symbols is greater than or equal to 0.50, the similarity threshold. The scoring matrix used in Version 10 of the Wisconsin Genetics Software Package® is BLOSUM62 (see, Henikoff and Henikoff, (1989) Proc. Natl. Acad. Sci. USA 89:10915).
Unless otherwise stated, sequence identity/similarity values provided herein refer to the value obtained using the BLAST 2.0 suite of programs using default parameters (Altschul, et al., (1997) Nucleic Acids Res. 25:3389-402).
As those of ordinary skill in the art will understand, BLAST searches assume that proteins can be modeled as random sequences. However, many real proteins comprise regions of nonrandom sequences, which may be homopolymeric tracts, short-period repeats, or regions enriched in one or more amino acids. Such low-complexity regions may be aligned between unrelated proteins even though other regions of the protein are entirely dissimilar. A number of low-complexity filter programs can be employed to reduce such low-complexity alignments. For example, the SEG (Wooten and Federhen, (1993) Comput. Chem. 17:149-63) and XNU (Claverie and States, (1993) Comput. Chem. 17:191-201) low-complexity filters can be employed alone or in combination.
Accordingly, in any of the embodiments described herein, the polynucleotide may encode a polypeptide that is at least 80% identical to any one of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573. For example, the polynucleotide may encode a polypeptide that is at least 81% identical, at least 82% identical, at least 83% identical, at least 84% identical, at least 85% identical, at least 86% identical, at least 87% identical, at least 88% identical, at least 89% identical, at least 90% identical, at least 91% identical, at least 92% identical, at least 93% identical, at least 94% identical, at least 95% identical, at least 96% identical, at least 97% identical, at least 98% identical, or at least 99% identical to the amino acid sequence of any one of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573.
Also provided is a recombinant DNA construct comprising any of the polynucleotides described herein. In certain embodiments, the recombinant DNA construct further comprises at least one regulatory element. In certain embodiments, the at least one regulatory element of the recombinant DNA construct comprises a promoter. In certain embodiments, the promoter is a heterologous promoter.
As used herein, a “recombinant DNA construct” comprises two or more operably linked DNA segments, preferably DNA segments that are not operably linked in nature (i.e., heterologous). Non-limiting examples of recombinant DNA constructs include a polynucleotide of interest operably linked to heterologous sequences, also referred to as “regulatory elements,” which aid in the expression, autologous replication, and/or genomic insertion of the sequence of interest. Such regulatory elements include, for example, promoters, termination sequences, enhancers, etc., or any component of an expression cassette; a plasmid, cosmid, virus, autonomously replicating sequence, phage, or linear or circular single-stranded or double-stranded DNA or RNA nucleotide sequence; and/or sequences that encode heterologous polypeptides.
The polynucleotides described herein can be provided in expression cassettes for expression in a plant of interest or any organism of interest. The cassette can include 5′ and 3′ regulatory sequences operably linked to a polynucleotide. “Operably linked” is intended to mean a functional linkage between two or more elements. For, example, an operable linkage between a polynucleotide of interest and a regulatory sequence (e.g., a promoter) is a functional link that allows for expression of the polynucleotide of interest. Operably linked elements may be contiguous or non-contiguous. When used to refer to the joining of two protein coding regions, operably linked is intended that the coding regions are in the same reading frame. The cassette may additionally contain at least one additional gene to be cotransformed into the organism. Alternatively, the additional gene(s) can be provided on multiple expression cassettes. Such an expression cassette is provided with a plurality of restriction sites and/or recombination sites for insertion of the polynucleotide to be under the transcriptional regulation of the regulatory regions. The expression cassette may additionally contain selectable marker genes.
The expression cassette can include in the 5′-3′ direction of transcription, a transcriptional and translational initiation region (e.g., a promoter), a polynucleotide, and a transcriptional and translational termination region (e.g., termination region) functional in plants. The regulatory regions (e.g., promoters, transcriptional regulatory regions, and translational termination regions) and/or the polynucleotide may be native/analogous to the host cell or to each other. Alternatively, the regulatory regions and/or the polynucleotide may be heterologous to the host cell or to each other.
As used herein, “heterologous” in reference to a sequence is a sequence that originates from a foreign species, or, if from the same species, is substantially modified from its native form in composition and/or genomic locus by deliberate human intervention. For example, a promoter operably linked to a heterologous polynucleotide that is from a species different from the species from which the polynucleotide was derived, or, if from the same/analogous species, one or both are substantially modified from their original form and/or genomic locus, or the promoter is not the native promoter for the operably linked polynucleotide.
The termination region may be native with the transcriptional initiation region, with the plant host, or may be derived from another source (i.e., foreign or heterologous) than the promoter, the polynucleotide, the plant host, or any combination thereof.
The expression cassette may additionally contain a 5′ leader sequences. Such leader sequences can act to enhance translation. Translation leaders are known in the art and include viral translational leader sequences.
In preparing the expression cassette, the various DNA fragments may be manipulated, to provide for the DNA sequences in the proper orientation and, as appropriate, in the proper reading frame. Toward this end, adapters or linkers may be employed to join the DNA fragments or other manipulations may be involved to provide for convenient restriction sites, removal of superfluous DNA, removal of restriction sites, or the like. For this purpose, in vitro mutagenesis, primer repair, restriction, annealing, resubstitutions, e.g., transitions and transversions, may be involved.
As used herein “promoter” refers to a region of DNA upstream from the start of transcription and involved in recognition and binding of RNA polymerase and other proteins to initiate transcription. A “plant promoter” is a promoter capable of initiating transcription in plant cells. Exemplary plant promoters include, but are not limited to, those that are obtained from plants, plant viruses and bacteria which comprise genes expressed in plant cells such Agrobacterium or Rhizobium. Certain types of promoters preferentially initiate transcription in certain tissues, such as leaves, roots, seeds, fibers, xylem vessels, tracheids or sclerenchyma. Such promoters are referred to as “tissue preferred.” A “cell type” specific promoter primarily drives expression in certain cell types in one or more organs, for example, vascular cells in roots or leaves. An “inducible” or “regulatable” promoter is a promoter, which is under environmental control. Examples of environmental conditions that may affect transcription by inducible promoters include anaerobic conditions or the presence of light. Another type of promoter is a developmentally regulated promoter, for example, a promoter that drives expression during pollen development. Tissue preferred, cell type specific, developmentally regulated and inducible promoters constitute the class of “non-constitutive” promoters. A “constitutive” promoter is a promoter, which is active under most environmental conditions. Constitutive promoters include, for example, the core promoter of the Rsyn7 promoter and other constitutive promoters disclosed in WO 99/43838 and U.S. Pat. No. 6,072,050; the core CaMV 35S promoter (Odell et al. (1985) Nature 313:810-812); rice actin (McElroy et al. (1990) Plant Cell 2:163-171); ubiquitin (Christensen et al. (1989) Plant Mol. Biol. 12:619-632 and Christensen et al. (1992) Plant Mol. Biol. 18:675-689); pEMU (Last et al. (1991) Theor. Appl. Genet. 81:581-588); MAS (Velten et al. (1984) EMBO J. 3:2723-2730); ALS promoter (U.S. Pat. No. 5,659,026); GOS2 (U.S. Pat. No. 6,504,083), and the like. Other constitutive promoters include, for example, U.S. Pat. Nos. 5,608,149; 5,608,144; 5,604,121; 5,569,597; 5,466,785; 5,399,680; 5,268,463; 5,608,142; and 6,177,611.
Also contemplated are synthetic promoters which include a combination of one or more heterologous regulatory elements.
Provided are plants, plant cells, plant parts, seed, and grain comprising a polynucleotide sequence described herein or a recombinant DNA construct described herein, so that the plants, plant cells, plant parts, seed, and/or grain have increased expression of a polypeptide. In certain embodiments, the plants, plant cells, plant parts, seeds, and/or grain have stably incorporated an exogenous polynucleotide described herein into its genome. In certain embodiments, the plants, plant cells, plant parts, seeds, and/or grain can comprise multiple polynucleotides (i.e., at least 1, 2, 3, 4, 5, 6 or more).
In specific embodiments, the polynucleotide(s) in the plants, plant cells, plant parts, seeds, and/or grain are operably linked to a heterologous regulatory element, such as, but not limited to, a constitutive promoter, a tissue-preferred promoter, or a synthetic promoter for expression in plants or a constitutive enhancer. For example, in certain embodiments the heterologous regulatory element is the maize GOS2 promoter.
Also provided herein are plants, plant cells, plant parts, seeds, and grain comprising an introduced genetic modification at a genomic locus that encodes a polypeptide comprising an amino acid sequence that is at least 80% identical to an amino acid sequence selected from the group consisting of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573.
In certain embodiments, the genetic modification increases the activity of the protein. In certain embodiments, the genetic modification increases the level of the protein. In certain embodiments, the genetic modification increases both the level and activity of the protein.
A “genomic locus” as used herein, generally refers to the location on a chromosome of the plant where a gene, such as a polynucleotide encoding a polypeptide, is found. As used herein, “gene” includes a nucleic acid fragment that expresses a functional molecule such as, but not limited to, a specific protein coding sequence and regulatory elements, such as those preceding (5′ non-coding sequences) and following (3′ non-coding sequences) the coding sequence.
A “regulatory element” generally refers to a transcriptional regulatory element involved in regulating the transcription of a nucleic acid molecule such as a gene or a target gene. The regulatory element is a nucleic acid and may include a promoter, an enhancer, an intron, a 5′-untranslated region (5′-UTR, also known as a leader sequence), or a 3′-UTR or a combination thereof. A regulatory element may act in “cis” or “trans”, and generally it acts in “cis”, i.e. it activates expression of genes located on the same nucleic acid molecule, e.g. a chromosome, where the regulatory element is located.
An “enhancer” element is any nucleic acid molecule that increases transcription of a nucleic acid molecule when functionally linked to a promoter regardless of its relative position.
A “repressor” (also sometimes called herein silencer) is defined as any nucleic acid molecule which inhibits the transcription when functionally linked to a promoter regardless of relative position.
The term “cis-element” generally refers to transcriptional regulatory element that affects or modulates expression of an operably linked transcribable polynucleotide, where the transcribable polynucleotide is present in the same DNA sequence. A cis-element may function to bind transcription factors, which are trans-acting polypeptides that regulate transcription.
An “intron” is an intervening sequence in a gene that is transcribed into RNA but is then excised in the process of generating the mature mRNA. The term is also used for the excised RNA sequences. An “exon” is a portion of the sequence of a gene that is transcribed and is found in the mature messenger RNA derived from the gene but is not necessarily a part of the sequence that encodes the final gene product.
The 5′ untranslated region (5′UTR) (also known as a translational leader sequence or leader RNA) is the region of an mRNA that is directly upstream from the initiation codon. This region is involved in the regulation of translation of a transcript by differing mechanisms in viruses, prokaryotes and eukaryotes.
The “3′ non-coding sequences” refer to DNA sequences located downstream of a coding sequence and include polyadenylation recognition sequences and other sequences encoding regulatory signals capable of affecting mRNA processing or gene expression. The polyadenylation signal is usually characterized by affecting the addition of polyadenylic acid tracts to the 3′ end of the mRNA precursor.
“Genetic modification,” “DNA modification,” and the like refers to a site-specific modification that alters or changes the nucleotide sequence at a specific genomic locus of the plant. The genetic modification of the compositions and methods described herein may be any modification known in the art such as, for example, insertion, deletion, single nucleotide polymorphism (SNP), and or a polynucleotide modification. Additionally, the targeted DNA modification in the genomic locus may be located anywhere in the genomic locus, such as, for example, a coding region of the encoded polypeptide (e.g., exon), a non-coding region (e.g., intron), a regulatory element, or untranslated region.
As used herein, a “targeted” genetic modification or “targeted” DNA modification, refers to the direct manipulation of an organism's genes. The targeted modification may be introduced using any technique known in the art, such as, for example, plant breeding, genome editing, or single locus conversion.
The type and location of the DNA modification of the polynucleotide is not particularly limited so long as the DNA modification results in increased expression and/or activity of the protein encoded by the corresponding polynucleotide.
In certain embodiments, the plant, plant cells, plant parts, seeds, and/or grain comprise one or more nucleotide modifications present within (a) the coding region; (b) non-coding region; (c) regulatory sequence; (d) untranslated region, or (e) any combination of (a)-(d) of an endogenous polynucleotide encoding a polypeptide.
In certain embodiments the DNA modification is an insertion of one or more nucleotides, preferably contiguous, in the genomic locus. For example, the insertion of an expression modulating element (EME), such as an EME described in PCT/US2018/025446, in operable linkage with the gene of interest described herein. In certain embodiments, the targeted DNA modification may be the replacement of an endogenous promoter with another promoter known in the art to have higher expression, such as, for example, the maize GOS2 promoter. In certain embodiments, the targeted DNA modification may be the insertion of a promoter known in the art to have higher expression, such as, for example, the maize GOS2 promoter, into the 5′UTR so that expression of the endogenous polypeptide is controlled by the inserted promoter. In certain embodiments, the DNA modification is a modification to optimize Kozak context to increase expression. In certain embodiments, the DNA modification is a polynucleotide modification or SNP at a site that regulates the stability of the expressed protein.
As used herein “increased,” “increase,” or the like refers to any detectable increase in an experimental group (e.g., plant with a DNA modification described herein) as compared to a control group (e.g., wild-type plant that does not comprise the DNA modification). Accordingly, increased expression of a protein comprises any detectable increase in the total level of the protein in a sample and can be determined using routine methods in the art such as, for example, Western blotting and ELISA.
In certain embodiments, the genomic locus has more than one (e.g., 2, 3, 4, 5, 6, 7, 8, 9, or 10) DNA modification. For example, the translated region and a regulatory element of a genomic locus may each comprise a targeted DNA modification. In certain embodiments, more than one genomic locus of the plant may comprise a DNA modification.
The DNA modification of the genomic locus may be done using any genome modification technique known in the art or described herein. In certain embodiments the targeted DNA modification is through a genome modification technique selected from the group consisting of a polynucleotide-guided endonuclease, CRISPR-Cas endonucleases, base editing deaminases, zinc finger nuclease, a transcription activator-like effector nuclease (TALEN), engineered site-specific meganuclease, or Argonaute.
In certain embodiments, the genome modification may be facilitated through the induction of a double-stranded break (DSB) or single-strand break, in a defined position in the genome near the desired alteration. DSBs can be induced using any DSB-inducing agent available, including, but not limited to, TALENs, meganucleases, zinc finger nucleases, Cas9-gRNA systems (based on bacterial CRISPR-Cas systems), guided cpfl endonuclease systems, and the like. In some embodiments, the introduction of a DSB can be combined with the introduction of a polynucleotide modification template.
The polynucleotides or recombinant DNA constructs disclosed herein may be used for transformation of any plant species, including, but not limited to, monocots and dicots. Additionally, the genetic modifications described herein may be used to modify any plant species, including, but not limited to, monocots and dicots.
In specific embodiments, plants of the present disclosure are crop plants (for example, corn, alfalfa, sunflower, Brassica, soybean, cotton, safflower, peanut, sorghum, wheat, millet, tobacco, etc.). In other embodiments, corn and soybean plants are optimal, and in yet other embodiments corn plants are optimal.
Other plants of interest include, for example, grain plants that provide seeds of interest, oil-seed plants, and leguminous plants. Seeds of interest include, for example, grain seeds, such as corn, wheat, barley, rice, sorghum, rye, etc. Oil-seed plants include, for example, cotton, soybean, safflower, sunflower, Brassica, maize, alfalfa, palm, coconut, etc. Leguminous plants include beans and peas. Beans include guar, locust bean, fenugreek, soybean, garden beans, cowpea, mungbean, lima bean, fava bean, lentils, chickpea.
For example, in certain embodiments, maize plants are provided that comprise, in their genome, a recombinant DNA construct comprising a polynucleotide that encodes a polypeptide comprising an amino acid sequence that is at least 80% to about 100% identical to any one of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573. In certain embodiments, the polypeptide comprising an amino acid sequence that is at least 80% to about 100% identical to the amino acid sequence of any one of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573 comprises the amino acid sequence set forth in SEQ ID NO: 28. In certain embodiments, the polypeptide comprising an amino acid sequence that is at least 80% to about 100% identical to the amino acid sequence of any one of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573.
In other embodiments, maize plants are provided that comprise a genetic modification at a genomic locus that encodes a polypeptide comprising an amino acid sequence that is at least 80% identical to the amino acid sequence of any one of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573. In certain embodiments, the polypeptide comprising an amino acid sequence that is at least 80% identical to the amino acid sequence of any one of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573 comprises the amino acid sequence set forth in SEQ ID NO: 28. In certain embodiments, the polypeptide comprising an amino acid sequence that is at least 80% identical to the amino acid sequence of any one of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573.
In some embodiments, the polynucleotides disclosed herein are engineered into a molecular stack. Thus, the various host cells, plants, plant cells, plant parts, seeds, and/or grain disclosed herein can further comprise one or more traits of interest. In certain embodiments, the host cell, plant, plant part, plant cell, seed, and/or grain is stacked with any combination of polynucleotide sequences of interest in order to create plants with a desired combination of traits. As used herein, the term “stacked” refers to having multiple traits present in the same plant or organism of interest. For example, “stacked traits” may comprise a molecular stack where the sequences are physically adjacent to each other. A trait, as used herein, refers to the phenotype derived from a particular sequence or groups of sequences. In one embodiment, the molecular stack comprises at least one polynucleotide that confers tolerance to glyphosate. Polynucleotides that confer glyphosate tolerance are known in the art.
In certain embodiments, the molecular stack comprises at least one polynucleotide that confers tolerance to glyphosate and at least one additional polynucleotide that confers tolerance to a second herbicide.
In certain embodiments, the plant, plant cell, seed, and/or grain having an inventive polynucleotide sequence may be stacked with, for example, one or more sequences that confer tolerance to: an ALS inhibitor; an HPPD inhibitor; 2,4-D; other phenoxy auxin herbicides; aryloxyphenoxypropionate herbicides; dicamba; glufosinate herbicides; herbicides which target the protox enzyme (also referred to as “protox inhibitors”).
The plant, plant cell, plant part, seed, and/or grain having an inventive polynucleotide sequence can also be combined with at least one other trait to produce plants that further comprise a variety of desired trait combinations. For instance, the plant, plant cell, plant part, seed, and/or grain having an inventive polynucleotide sequence may be stacked with polynucleotides encoding polypeptides having pesticidal and/or insecticidal activity, or a plant, plant cell, plant part, seed, and/or grain having an inventive polynucleotide sequence may be combined with a plant disease resistance gene.
These stacked combinations can be created by any method including, but not limited to, breeding plants by any conventional methodology, or genetic transformation. If the sequences are stacked by genetically transforming the plants, the polynucleotide sequences of interest can be combined at any time and in any order. The traits can be introduced simultaneously in a co-transformation protocol with the polynucleotides of interest provided by any combination of transformation cassettes. For example, if two sequences will be introduced, the two sequences can be contained in separate transformation cassettes (trans) or contained on the same transformation cassette (cis). Expression of the sequences can be driven by the same promoter or by different promoters. In certain cases, it may be desirable to introduce a transformation cassette that will suppress the expression of the polynucleotide of interest. This may be combined with any combination of other suppression cassettes or overexpression cassettes to generate the desired combination of traits in the plant. It is further recognized that polynucleotide sequences can be stacked at a desired genomic location using a site-specific recombination system. See, for example, WO99/25821, WO99/25854, WO99/25840, WO99/25855, and WO99/25853, all of which are herein incorporated by reference. Any plant having an inventive polynucleotide sequence disclosed herein can be used to make a food or a feed product. Such methods comprise obtaining a plant, explant, seed, plant cell, or cell comprising the polynucleotide sequence and processing the plant, explant, seed, plant cell, or cell to produce a food or feed product.
Provided are methods for increasing yield in a plant, modifying flowering time of a plant, and/or increasing the activity of one or more polynucleotides disclosed herein in a plant comprising introducing into a plant, plant cell, plant part, seed, and/or grain a recombinant DNA construct comprising any of the inventive polynucleotides described herein, whereby the polypeptide is expressed in the plant. Also provided are methods for increasing yield in a plant, modifying flowering time of a plant, and/or increasing the activity in a plant comprising introducing a genetic modification at a genomic locus of a plant that encodes a polypeptide comprising an amino acid sequence that is at least 80%-99% or 100% identical to the amino acid sequence set for in any one of SEQ ID NOS: 1-11, 23-31, 40-299, 563, 565, and 567-573.
The plant for use in the inventive methods can be any plant species described herein. In certain embodiments, the plant is a grain plant, an oil-seed plant, or leguminous plant. In certain embodiments, the plant is a grain plant such as maize.
As used herein, “yield” refers to the amount of agricultural production harvested per unit of land and may include reference to bushels per acre of a crop at harvest, as adjusted for grain moisture (e.g., typically 15% for maize). Grain moisture is measured in the grain at harvest. The adjusted test weight of grain is determined to be the weight in pounds per bushel, adjusted for grain moisture level at harvest.
In certain embodiments yield is measured in plants grown under optimal growth conditions. As used herein, “optimal conditions” refers to plants that are grown under well-watered or non-drought conditions. In certain embodiments, optimal growth conditions are determined based on the yield of the wild-type control plants in the experiment. As used herein, plants are considered to be grown under optimal conditions when the wild-type plant provides at least 75% of the predicted grain yield.
As used herein, “modifying flowering time” refers to a change in the number of days or growth heat units required for a plant to flower. In certain embodiments, the flowering time of the plant is delayed upon increased expression of the polypeptide. Also contemplated are embodiments in which flowering time is decreased (i.e., less days or growth heat units required for a plant to flower) upon decreased expression of the polypeptide.
As used herein, increase in photosynthetic activity, refers to any detectable increase in the functional activity of the protein compared to a suitable control. The functional activity may be any known biological property of one or more of the polypeptides disclosed herein and includes, for example, increased formation of protein complexes, modulation of biochemical pathways, and/or increased grain yield.
Various methods can be used to introduce a sequence of interest into a plant, plant part, plant cell, seed, and/or grain. “Introducing” is intended to mean presenting to the plant, plant cell, seed, and/or grain the inventive polynucleotide or resulting polypeptide in such a manner that the sequence gains access to the interior of a cell of the plant. The methods of the disclosure do not depend on a particular method for introducing a sequence into a plant, plant cell, seed, and/or grain, only that the polynucleotide or polypeptide gains access to the interior of at least one cell of the plant.
“Stable transformation” is intended to mean that the polynucleotide introduced into a plant integrates into the genome of the plant of interest and is capable of being inherited by the progeny thereof. “Transient transformation” is intended to mean that a polynucleotide is introduced into the plant of interest and does not integrate into the genome of the plant or organism or a polypeptide is introduced into a plant or organism.
Transformation protocols as well as protocols for introducing polypeptides or polynucleotide sequences into plants may vary depending on the type of plant or plant cell, i.e., monocot or dicot, targeted for transformation.
In specific embodiments, the polynucleotide sequences disclosed herein can be provided to a plant using a variety of transient transformation methods. Such transient transformation methods include, but are not limited to, the introduction of the encoded protein directly into the plant. Such methods include, for example, microinjection or particle bombardment. See, for example, Crossway et al. (1986) Mol Gen. Genet. 202:179-185; Nomura et al. (1986) Plant Sci. 44:53-58; Hepler et al. (1994) Proc. Natl. Acad. Sci. 91: 2176-2180 and Hush et al. (1994) The Journal of Cell Science 107:775-784, all of which are herein incorporated by reference.
In other embodiments, the inventive polynucleotides disclosed herein may be introduced into plants by contacting plants with a virus or viral nucleic acids. Generally, such methods involve incorporating a nucleotide construct of the disclosure within a DNA or RNA molecule. It is recognized that the inventive polynucleotide sequence may be initially synthesized as part of a viral polyprotein, which later may be processed by proteolysis in vivo or in vitro to produce the desired recombinant protein. Further, it is recognized that promoters disclosed herein also encompass promoters utilized for transcription by viral RNA polymerases. Methods for introducing polynucleotides into plants and expressing a protein encoded therein, involving viral DNA or RNA molecules, are known in the art. See, for example, U.S. Pat. Nos. 5,889,191, 5,889,190, 5,866,785, 5,589,367, 5,316,931, and Porta et al. (1996) Molecular Biotechnology 5:209-221; herein incorporated by reference.
Various methods can be used to introduce a genetic modification at a genomic locus that encodes and polypeptide into the plant, plant part, plant cell, seed, and/or grain. In certain embodiments the targeted DNA modification is through a genome modification technique selected from the group consisting of a polynucleotide-guided endonuclease, CRISPR-Cas endonucleases, base editing deaminases, zinc finger nuclease, a transcription activator-like effector nuclease (TALEN), engineered site-specific meganuclease, or Argonaute.
In some embodiments, the genome modification may be facilitated through the induction of a double-stranded break (DSB) or single-strand break, in a defined position in the genome near the desired alteration. DSBs can be induced using any DSB-inducing agent available, including, but not limited to, TALENs, meganucleases, zinc finger nucleases, Cas9-gRNA systems (based on bacterial CRISPR-Cas systems), guided cpfl endonuclease systems, and the like. In some embodiments, the introduction of a DSB can be combined with the introduction of a polynucleotide modification template.
A polynucleotide modification template can be introduced into a cell by any method known in the art, such as, but not limited to, transient introduction methods, transfection, electroporation, microinjection, particle mediated delivery, topical application, whiskers mediated delivery, delivery via cell-penetrating peptides, or mesoporous silica nanoparticle (MSN)-mediated direct delivery.
The polynucleotide modification template can be introduced into a cell as a single stranded polynucleotide molecule, a double stranded polynucleotide molecule, or as part of a circular DNA (vector DNA). The polynucleotide modification template can also be tethered to the guide RNA and/or the Cas endonuclease. Tethered DNAs can allow for co-localizing target and template DNA, useful in genome editing and targeted genome regulation, and can also be useful in targeting post-mitotic cells where function of endogenous HR machinery is expected to be highly diminished (Mali et al. 2013 Nature Methods Vol. 10: 957-963.) The polynucleotide modification template may be present transiently in the cell or it can be introduced via a viral replicon.
A “modified nucleotide” or “edited nucleotide” refers to a nucleotide sequence of interest that comprises at least one alteration when compared to its non-modified nucleotide sequence. Such “alterations” include, for example: (i) replacement of at least one nucleotide, (ii) a deletion of at least one nucleotide, (iii) an insertion of at least one nucleotide, or (iv) any combination of (i)-(iii).
The term “polynucleotide modification template” includes a polynucleotide that comprises at least one nucleotide modification when compared to the nucleotide sequence to be edited. A nucleotide modification can be at least one nucleotide substitution, addition or deletion. Optionally, the polynucleotide modification template can further comprise homologous nucleotide sequences flanking the at least one nucleotide modification, wherein the flanking homologous nucleotide sequences provide sufficient homology to the desired nucleotide sequence to be edited.
The process for editing a genomic sequence combining DSB and modification templates generally comprises: providing to a host cell, a DSB-inducing agent, or a nucleic acid encoding a DSB-inducing agent, that recognizes a target sequence in the chromosomal sequence and is able to induce a DSB in the genomic sequence, and at least one polynucleotide modification template comprising at least one nucleotide alteration when compared to the nucleotide sequence to be edited. The polynucleotide modification template can further comprise nucleotide sequences flanking the at least one nucleotide alteration, in which the flanking sequences are substantially homologous to the chromosomal region flanking the DSB.
The endonuclease can be provided to a cell by any method known in the art, for example, but not limited to, transient introduction methods, transfection, microinjection, and/or topical application or indirectly via recombination constructs. The endonuclease can be provided as a protein or as a guided polynucleotide complex directly to a cell or indirectly via recombination constructs. The endonuclease can be introduced into a cell transiently or can be incorporated into the genome of the host cell using any method known in the art. In the case of a CRISPR-Cas system, uptake of the endonuclease and/or the guided polynucleotide into the cell can be facilitated with a Cell Penetrating Peptide (CPP) as described in WO2016073433 published May 12, 2016.
In addition to modification by a double strand break technology, modification of one or more bases without such double strand break are achieved using base editing technology, see e.g., Gaudelli et al., (2017) Programmable base editing of A*T to G*C in genomic DNA without DNA cleavage. Nature 551(7681):464-471; Komor et al., (2016) Programmable editing of a target base in genomic DNA without double-stranded DNA cleavage, Nature 533(7603):420-4.
These fusions contain dCas9 or Cas9 nickase and a suitable deaminase, and they can convert e.g., cytosine to uracil without inducing double-strand break of the target DNA. Uracil is then converted to thymine through DNA replication or repair. Improved base editors that have targeting flexibility and specificity are used to edit endogenous locus to create target variations and improve grain yield. Similarly, adenine base editors enable adenine to inosine change, which is then converted to guanine through repair or replication. Thus, targeted base changes i.e., C⋅G to T⋅A conversion and A⋅T to G⋅C conversion at one more locations made using appropriate site-specific base editors.
In an embodiment, base editing is a genome editing method that enables direct conversion of one base pair to another at a target genomic locus without requiring double-stranded DNA breaks (DSBs), homology-directed repair (HDR) processes, or external donor DNA templates. In an embodiment, base editors include (i) a catalytically impaired CRISPR-Cas9 mutant that are mutated such that one of their nuclease domains cannot make DSBs; (ii) a single-strand-specific cytidine/adenine deaminase that converts C to U or A to G within an appropriate nucleotide window in the single-stranded DNA bubble created by Cas9; (iii) a uracil glycosylase inhibitor (UGI) that impedes uracil excision and downstream processes that decrease base editing efficiency and product purity; and (iv) nickase activity to cleave the non-edited DNA strand, followed by cellular DNA repair processes to replace the G-containing DNA strand.
As used herein, a “genomic region” is a segment of a chromosome in the genome of a cell that is present on either side of the target site or, alternatively, also comprises a portion of the target site. The genomic region can comprise at least 5-10, 5-15, 5-20, 5-25, 5-30, 5-35, 5-40, 5-45, 5-50, 5-55, 5-60, 5-65, 5-70, 5-75, 5-80, 5-85, 5-90, 5-95, 5-100, 5-200, 5-300, 5-400, 5-500, 5-600, 5-700, 5-800, 5-900, 5-1000, 5-1100, 5-1200, 5-1300, 5-1400, 5-1500, 5-1600, 5-1700, 5-1800, 5-1900, 5-2000, 5-2100, 5-2200, 5-2300, 5-2400, 5-2500, 5-2600, 5-2700, 5-2800. 5-2900, 5-3000, 5-3100 or more bases such that the genomic region has sufficient homology to undergo homologous recombination with the corresponding region of homology.
TAL effector nucleases (TALEN) are a class of sequence-specific nucleases that can be used to make double-strand breaks at specific target sequences in the genome of a plant or other organism. (Miller et al. (2011) Nature Biotechnology 29:143-148).
Endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain. Endonucleases include restriction endonucleases, which cleave DNA at specific sites without damaging the bases, and meganucleases, also known as homing endonucleases (HEases), which like restriction endonucleases, bind and cut at a specific recognition site, however the recognition sites for meganucleases are typically longer, about 18 bp or more (patent application PCT/US12/30061, filed on Mar. 22, 2012). Meganucleases have been classified into four families based on conserved sequence motifs, the families are the LAGLIDADG, GIY-YIG, H—N—H, and His-Cys box families. These motifs participate in the coordination of metal ions and hydrolysis of phosphodiester bonds. HEases are notable for their long recognition sites, and for tolerating some sequence polymorphisms in their DNA substrates. The naming convention for meganuclease is similar to the convention for other restriction endonuclease. Meganucleases are also characterized by prefix F-, I-, or PI- for enzymes encoded by free-standing ORFs, introns, and inteins, respectively. One step in the recombination process involves polynucleotide cleavage at or near the recognition site. The cleaving activity can be used to produce a double-strand break. For reviews of site-specific recombinases and their recognition sites, see, Sauer (1994) Curr Op Biotechnol 5:521-7; and Sadowski (1993) FASEB 7:760-7. In some examples the recombinase is from the Integrase or Resolvase families.
Zinc finger nucleases (ZFNs) are engineered double-strand break inducing agents comprised of a zinc finger DNA binding domain and a double-strand-break-inducing agent domain. Recognition site specificity is conferred by the zinc finger domain, which typically comprising two, three, or four zinc fingers, for example having a C2H2 structure, however other zinc finger structures are known and have been engineered. Zinc finger domains are amenable for designing polypeptides which specifically bind a selected polynucleotide recognition sequence. ZFNs include an engineered DNA-binding zinc finger domain linked to a non-specific endonuclease domain, for example nuclease domain from a Type IIs endonuclease such as FokI. Additional functionalities can be fused to the zinc-finger binding domain, including transcriptional activator domains, transcription repressor domains, and methylases. In some examples, dimerization of nuclease domain is required for cleavage activity. Each zinc finger recognizes three consecutive base pairs in the target DNA. For example, a 3 finger domain recognized a sequence of 9 contiguous nucleotides, with a dimerization requirement of the nuclease, two sets of zinc finger triplets are used to bind an 18 nucleotide recognition sequence.
Genome editing using DSB-inducing agents, such as Cas9-gRNA complexes, has been described, for example in U.S. Patent Application US 2015-0082478 A1, published on Mar. 19, 2015, WO2015/026886 A1, published on Feb. 26, 2015, WO2016007347, published on Jan. 14, 2016, and WO201625131, published on Feb. 18, 2016, all of which are incorporated by reference herein.
A guide polynucleotide/Cas endonuclease complex can cleave one or both strands of a DNA target sequence. A guide polynucleotide/Cas endonuclease complex that can cleave both strands of a DNA target sequence typically comprise a Cas protein that has all of its endonuclease domains in a functional state (e.g., wild type endonuclease domains or variants thereof retaining some or all activity in each endonuclease domain). Non-limiting examples of Cas9 nickases suitable for use herein are disclosed in U.S. Patent Appl. Publ. No. 2014/0189896, which is incorporated herein by reference.
Other Cas endonuclease systems have been described in PCT patent applications PCT/US16/32073, filed May 12, 2016 and PCT/US16/32028 filed May 12, 2016, both applications incorporated herein by reference.
The terms “target site”, “target sequence”, “target site sequence, “target DNA”, “target locus”, “genomic target site”, “genomic target sequence”, “genomic target locus” and “protospacer”, are used interchangeably herein and refer to a polynucleotide sequence such as, but not limited to, a nucleotide sequence on a chromosome, episome, or any other DNA molecule in the genome (including chromosomal, choloroplastic, mitochondrial DNA, plasmid DNA) of a cell, at which a guide polynucleotide/Cas endonuclease complex can recognize, bind to, and optionally nick or cleave. The target site can be an endogenous site in the genome of a cell, or alternatively, the target site can be heterologous to the cell and thereby not be naturally occurring in the genome of the cell, or the target site can be found in a heterologous genomic location compared to where it occurs in nature. As used herein, terms “endogenous target sequence” and “native target sequence” are used interchangeable herein to refer to a target sequence that is endogenous or native to the genome of a cell and is at the endogenous or native position of that target sequence in the genome of the cell. Cells include, but are not limited to, human, non-human, animal, bacterial, fungal, insect, yeast, non-conventional yeast, and plant cells as well as plants and seeds produced by the methods described herein. An “artificial target site” or “artificial target sequence” are used interchangeably herein and refer to a target sequence that has been introduced into the genome of a cell. Such an artificial target sequence can be identical in sequence to an endogenous or native target sequence in the genome of a cell but be located in a different position (i.e., a non-endogenous or non-native position) in the genome of a cell.
An “altered target site”, “altered target sequence”, “modified target site”, “modified target sequence” are used interchangeably herein and refer to a target sequence as disclosed herein that comprises at least one alteration when compared to non-altered target sequence. Such “alterations” include, for example: (i) replacement of at least one nucleotide, (ii) a deletion of at least one nucleotide, (iii) an insertion of at least one nucleotide, or (iv) any combination of (i)-(iii).
Methods for “modifying a target site” and “altering a target site” are used interchangeably herein and refer to methods for producing an altered target site.
The length of the target DNA sequence (target site) can vary, and includes, for example, target sites that are at least 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 or more nucleotides in length. It is further possible that the target site can be palindromic, that is, the sequence on one strand reads the same in the opposite direction on the complementary strand. The nick/cleavage site can be within the target sequence or the nick/cleavage site could be outside of the target sequence. In another variation, the cleavage could occur at nucleotide positions immediately opposite each other to produce a blunt end cut or, in other Cases, the incisions could be staggered to produce single-stranded overhangs, also called “sticky ends”, which can be either 5′ overhangs, or 3′ overhangs. Active variants of genomic target sites can also be used. Such active variants can comprise at least 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more sequence identity to the given target site, wherein the active variants retain biological activity and hence are capable of being recognized and cleaved by an Cas endonuclease. Assays to measure the single or double-strand break of a target site by an endonuclease are known in the art and generally measure the overall activity and specificity of the agent on DNA substrates containing recognition sites.
A “protospacer adjacent motif” (PAM) herein refers to a short nucleotide sequence adjacent to a target sequence (protospacer) that is recognized (targeted) by a guide polynucleotide/Cas endonuclease system described herein. The Cas endonuclease may not successfully recognize a target DNA sequence if the target DNA sequence is not followed by a PAM sequence. The sequence and length of a PAM herein can differ depending on the Cas protein or Cas protein complex used. The PAM sequence can be of any length but is typically 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 nucleotides long.
The terms “targeting”, “gene targeting” and “DNA targeting” are used interchangeably herein. DNA targeting herein may be the specific introduction of a knock-out, edit, or knock-in at a particular DNA sequence, such as in a chromosome or plasmid of a cell. In general, DNA targeting can be performed herein by cleaving one or both strands at a specific DNA sequence in a cell with an endonuclease associated with a suitable polynucleotide component. Such DNA cleavage, if a double-strand break (DSB), can prompt NHEJ or HDR processes which can lead to modifications at the target site.
A targeting method herein can be performed in such a way that two or more DNA target sites are targeted in the method, for example. Such a method can optionally be characterized as a multiplex method. Two, three, four, five, six, seven, eight, nine, ten, or more target sites can be targeted at the same time in certain embodiments. A multiplex method is typically performed by a targeting method herein in which multiple different RNA components are provided, each designed to guide an guidepolynucleotide/Cas endonuclease complex to a unique DNA target site.
The terms “knock-out”, “gene knock-out” and “genetic knock-out” are used interchangeably herein. A knock-out represents a DNA sequence of a cell that has been rendered partially or completely inoperative by targeting with a Cas protein; such a DNA sequence prior to knock-out could have encoded an amino acid sequence, or could have had a regulatory function (e.g., promoter), for example. A knock-out may be produced by an indel (insertion or deletion of nucleotide bases in a target DNA sequence through NHEJ), or by specific removal of sequence that reduces or completely destroys the function of sequence at or near the targeting site.
The guide polynucleotide/Cas endonuclease system can be used in combination with a co-delivered polynucleotide modification template to allow for editing (modification) of a genomic nucleotide sequence of interest. (See also U.S. Patent Application US 2015-0082478 A1, published on Mar. 19, 2015 and WO2015/026886 A1, published on Feb. 26, 2015, both are hereby incorporated in its entirety by reference.)
The terms “knock-in”, “gene knock-in, “gene insertion” and “genetic knock-in” are used interchangeably herein. A knock-in represents the replacement or insertion of a DNA sequence at a specific DNA sequence in cell by targeting with a Cas protein (by HR, wherein a suitable donor DNA polynucleotide is also used). Examples of knock-ins are a specific insertion of a heterologous amino acid coding sequence in a coding region of a gene, or a specific insertion of a transcriptional regulatory element in a genetic locus.
The following are examples of specific embodiments of some aspects of the invention. The examples are offered for illustrative purposes only and are not intended to limit the scope of the invention in any way.
This example demonstrates the interaction of other polypeptides with Zmm28 transcription factor (SEQ ID NO: 562). MADS-box transcription factors associate as homo- or hetero-dimers to bind CArG box elements and subsequently modulate target gene expression. To identify protein-protein interaction partners that potentially interact with native ZMM28 protein, Yeast Two-Hybrid (Y2H) screening was performed with a B73 immature ear library resulting in the identification of six potential MADS box protein-protein interaction partners (Table 2a).
Since native zmm28 does not express at early growth stages, protein-protein interaction partners contributing to the transgenic maize events phenotypes in seedlings and young leaves were assayed using Y2H screening of a PH184C seedling (V2-V3) library and a B73 V3-V7 leaf library. Nine total interacting proteins, none of which are MADS box proteins, were identified from the two libraries.
Potential interaction partners of ZMM28 were further tested in vivo with a bimolecular fluorescence complementation (BiFC) assay. Following transfection of maize protoplasts, fluorescence was measured indicating interaction between nGFP-Prey and cGFP-ZMM28 (Bait). As BiFC is prone to false-positive self-assembly independent of protein-protein interaction, flow cytometry was used to quantify the BiFC signal and reduce the occurrence of false positives. All signal comparisons were made to a negative control providing a baseline for self-assembly. The control was created by deleting 47 amino acids from the leucine zipper-like K-domain of ZMMADSL6, a protein interaction partner of ZMM28 identified from bioinformatics prediction and Y2H experiment. Truncated ZMMADSL6 (ZMMADSL6-MUT) had significantly reduced interaction with ZMM28 relative to WT ZMMADSL6 while still maintaining nuclear localization. Of the 12 tested protein interactions, eight were confirmed via the BiFC assay with almost half the interactions confirmed positive in both BiFC and Y2H assays (Table 2a). Table 2: ZMM28 protein-protein interactions, transcription, direct targets.
indicates data missing or illegible when filed
Table 2(a) provides a summary of protein-protein interactions with potential contribution to transgenically expressed zmm28. Expression values are from RNA-seq from transgenic V6 maize leaves and are normalized to zmm28. A “+” was listed for protein-interaction predictions based on yeast two-hybrid (Y2H); maize protoplast BiFC; and in heterodimer yeast one-hybrid (HY1H). (b) GO-term enrichment for transcriptomic analysis of DP202216 V6 leaf tissue. Photosynthesis related includes GO Terms 0015979, 0009765, 0019684, 0006091, 0033013, 0034357, 0044436, and 0009579. (d) Summary of promoter direct target analysis and expression in V6 leaves of event DP202216. 1 P=biological process, F=molecular function, C=cellular component. 2 Number of genes associated with each GO term that are differentially expressed between control and event DP202216 V6 leaf, DEG=differentially expressed gene. 3 Total number of genes in each GO category expressed in V6 leaf total detected transcripts. 4 Fisher's exact test for GO term enrichment. 5 False discovery rate. 6 V6 Leaf. * Statistically significant (adjusted p<0.05).
Pathway analysis of differentially expressed gene transcripts are shown above. Log 2 fold change heat maps of differentially expressed genes functioning in enriched pathways in event DP202216 V6 leaf tissue.
Yeast two-hybrid assay. A commercially available yeast two-hybrid system (Clontech (USA)/Takara (Japan) was used to discover and test for potential protein interaction partners with ZMM28. Three maize cDNA prey libraries were constructed from B73 V12-V14 immature ear, PH184C V2-V3 whole seedling, and B73 V3-V7 leaf RNA. The cDNA libraries were generated using SMART technology and co-transformed with linearized pGADT7-Rec into Yeast Strain Y187. At least one million prey clones from each library were mated to a ZMM28 bait strain. Mating was continued until zygotes could be observed using a light microscope and then plated on QDO/-Ade/-His/-Leu/-Trp and incubated at 30° C. for 5 days. Identified protein interaction partners were re-transformed into the Y2H system for confirmation testing.
Bimolecular fluorescence complementation (BiFC). Coding sequences for candidate protein-protein interaction partners to ZMM28 were synthesized by GenScript (USA) and placed under the control of the ZmGos2 promoter with a ZmUbi intron 1. The coding sequences were translationally fused to the C-terminal or N-terminal part of the monomeric Ac-GFP1 (Clontech, USA/Takara, Japan) with a 30× Glutamine linker. ZMMADSL6 was selected as a positive control in the BiFC assay as it was confirmed to interact with ZMM28 by Y2H. A truncated version of ZMMADSL6 without the protein interaction domain (a leucine zipper like region in the K-domain) was generated as a negative control.
Maize seedlings were germinated and grown in Fafard Super Fine Germination Mix for 6 days in a lighted growth chamber (30° C., 60% RH, 24 h light) and were transferred to a dark growth chamber (30° C., 60% RH, 0 h light) and grown for an additional 4 days to V1. Seedlings were sub-irrigated with deionized water. Maize protoplasts were isolated from these seedlings and were transiently transformed by PEG-mediated transfection as described by Yoo et al.63 with the addition of 0.6 M mannitol in the enzyme, WI, W5 and MMG solutions. Protoplasts were transfected with 10 pmol bait+10 pmol prey plasmid DNA per 3×104 cells. Protoplasts were incubated on a 12-well (1 mL WI) plate for 20 hours at RT before samples were analyzed.
BiFC signals were detected by flow cytometry performed using an Attune™ Flow Cytometer (Thermo Fisher Scientific, Waltham, Mass., USA) with a Blue/Violet configuration (488 nm, 20 mW laser and a 405 nm, 50 mW laser). Protoplasts were first gated (R1) by forward scatter (FSC) and side scatter (SCC) to identify 10,000 intact cells (events) and subsequently analyzed for fluorescence emission measured on BL1 (530/30 nm band pass filter) and BL2 (574/26 nm band pass filter) to distinguish between cells exhibiting the BiFC signal (R2) and auto-fluorescence. At least two independent experiments were performed for each protein interaction test with the positive and negative controls present in every experiment. All experiments were designed and analyzed as single factor randomized complete blocks with n=4. Significant differences were determined by analysis of variance with P<0.05 comparing protein interaction partners to the truncated ZMMADSL6 (ZMMADSL6-MUT) negative control. Western blots were used to confirm expression in cells transfected with the negative control ZMMADSL6-MUT (prey) and ZMM28 (bait).
RNA-Seq of ZmGos2-zmm28 and control and data analysis. DP202216 was selected for in-depth molecular analysis due to its more favorable insertion region. RNA-Seq libraries were constructed from four biological replicates of control and DP202216 youngest fully expanded leaves at V6 stage. Sequencing was performed on an Illumina HiSeq2500 (Illumina, Inc., USA) with a total read count of 154 million, and a minimum of 12 million reads per sample. RNA-Seq data were aligned to a proprietary maize B73 reference genome using Bowtie 2. Overall loci abundances were estimated using the expected fragment counts metric computed by RSEM65. Samples were vetted for quality by “Robust Principal Components based on Projection Pursuit (PP): GRID search Algorithm” in the “Scalable Robust Estimators with High Breakdown Point” R package [https://cran.r-project.org/package=rrcov]. Fold change was computed and hypothesis tests for differential expression were run using DESeq2, which fits the following model:
Where Kij is the observed count for gene i in sample j following a Negative Binomial distribution, (μij, αi, sj, qij) are all parameters fit to the data (see citation), xj. is 1 if sample j is transgenic and 0 if it is control and βi contains the log2 fold changes for gene i across all high-nitrogen leaf samples.
All genes in the proprietary reference genome were converted to public gene model identifiers. The DEGs were then annotated with Gene Ontology terms and differential gene set enrichment was done comparing to the total publicly mapped transcript set for the entire V6 leaf data set using AgriGO.
Chromatin immunoprecipitation and sequencing (ChIP-seq) data analysis. Chromatin immunoprecipitation (ChIP) was performed in duplicate on the youngest fully expanded leaf from V4 control and DP202216 maize plants using an anti-ZMM28 antibody (R743); ChIP without antibody was included as a control for each sample. Sequencing was performed on an Illumina HiSeq2500 (Illumina, Inc., USA) with a total read count of 461 million, with a minimum of 26 million reads per sample. ChIP-Seq reads were aligned to a proprietary maize B73 reference genome using Bowtie 2. Alignments were then fed to MACS 2.071 in order to detect differential binding in the transgenic samples. Reproducible peaks were then selected using Irreproducible Discovery Rate (IDR) analysis.
Values represent BiFC positive cell counts from selected gate strategies out of 10,000 cells in representative flow cytometry experiments. Negative- and positive-control cell counts represent fluorescent cells in protoplast populations co-transfected with BiFC fusion constructs of truncated ZmMADSL6 and ZMM28 or full length ZmMADSL6 and ZMM28, respectively. GOI=gene of interest. +/− indicates whether the BiFC assay was concluded to be positive (+) or negative (−) based on the p-value calculations.
This example demonstrates the analysis behind identification of the direct targets of Zmm28. To identify genes directly modulated by transgenic ZMM28 and their associated pathways, genomic sequences directly bound by ZMM28 were recovered from leaves of control and DP202216 plants at the V4 stage, at which time no detectable native ZMM28 protein is produced, and analyzed by chromatin immunoprecipitation and sequencing (ChIP-Seq). In addition, putative direct targets of the transgenic ZMM28 were identified from CArG-motif enrichment of the promoters from the strong differentially regulated DEGs in the transcriptome experiment.
Two in-cell assays were used to collectively validate candidate direct target promoters identified from above two experiments. A heterodimer Yeast One-Hybrid (HY1H) assay analyzed the capability of ZMM28 and one of its protein-protein interaction partners to directly bind a promoter. Additionally, V2 etiolated maize protoplast cells were used in a protoplast direct-target assay using a ZsGreen1 reporter to detect ZMM28 interactions with promoters. The HY1H assay provided predetermined heterodimer interaction partners while the maize protoplast direct-target assay potentially tested ZMM28 homodimers or heterodimers, forming between native protein-protein interaction partners. Promoters of key photosynthetic pathway components were bound by ZMM28, as were promoters of gibberellin and auxin receptor genes which are responsible for sensing these phytohormones (Table 2d).
Potential direct target genes (directly bound by the ZMM28 transcription factor) in V4 leaf ChIP-Seq data and select RNA-seq DEG candidates which contain CArG-boxes in the 3 kb upstream of the coding sequence were then screened based on potential function. Promoters of genes with known functional relevance and identifiable CArG sequences were synthesized (Genscript, USA) for direct target assays. Synthesized sequences were cloned into pAbAi (Clontech, USA/TAKARA, Japan) for inclusion in Yeast One-Hybrid assays with ZMM28 and Heterodimer Yeast One-Hybrid assays with ZMM28 and ZMM28 protein-protein interaction partners. Promoter sequences were integrated into the Yeast One-Hybrid Gold strain and individually transformed with a ZMM28-prey plasmid to test for protein-DNA interactions per the Yeast One-Hybrid manual. Heterodimer Yeast One-Hybrid was similarly performed, but including ZMM28 encoded on a Yeast Two-Hybrid bait plasmid (pGBK-T7) and ZMM28 protein-protein interaction partners encoded on a prey (pGAD-T7) plasmid.
Plant cell-based direct target assays were conducted in maize protoplasts. Protoplasts were isolated and transfected as described above. Reporter constructs consisted of the synthesized promoter sequences identified above transcriptionally fused to a ZsGreen1 (Clontech, USA/TAKARA, Japan) coding sequence followed by a pinII terminator. Effector constructs comprised a maize Gos2 promoter followed by a maize ZmUbi intron driving an effector protein coding sequence. Effector proteins were ZMM28, ZMM28 translationally fused to a 5×VP16 transcriptional activation domain, or β-glucuronidase as a negative control. Protoplasts were evaluated with flow cytometry with similar methodology to above.
This example demonstrates identification of several differentially expressed genes in plants expressing Zmm28 transgenically. Transcriptome analysis was conducted to identify differentially-expressed genes (DEGs) and their associated pathways that could provide a possible molecular basis for the previously described increased photosynthesis, N uptake, and plant growth. For simplicity, RNA-seq analysis was focused on V6 leaves from DP202216 and control plants. Results of this analysis identified 192 up-regulated and 64 down-regulated transcripts in DP202216 leaves as compared to the control leaf data (Table 3). CArG box sequences were contained within 3 kb upstream of their promoters in 76% of the DEGs, relative to 26-28% of DEGs from two over-expressed non-MADS transcription factors over a total of four experiments. These results suggest that many of the DEGs may be directly regulated by transgenic ZMM28 binding to their promoters at the V6 stage.
To further gain a global view of the differentially-expressed gene (DEG) function, Gene Ontology (GO) enrichment analysis was conducted and 11 GO terms were identified in the V6 leaf DEG dataset (Table 2b,c). Photosynthesis, generation of precursor metabolites and energy, as well as carbohydrate metabolic processes were the three main GO terms identified, all of which could contribute to promote plant growth and development. These results are consistent with the measured phenotypes of ZmGos2-zmm28 plants and suggest that photosynthesis and carbon assimilation-related genes expression are responsible for the measured grain yield increase.
Polynucleotide sequences encoding a polypeptide represented by one of SEQ ID NOS: 40-222 and polynucleotide sequences represented by one of SEQ ID NOS: 285-484 and 548-561 exhibit increased expression in plants that have increased and extended expression of Zmm28, compared to a control maize plant. Therefore, these sequences and their allelic variants representing about 95% sequence identity to one of SEQ ID NOS: 40-222, 285-484 and 548-561 are suitable for expression modulation and/or activity modulation to improve agronomic characteristics of maize. This can be achieved by a variety of means, transgenic up-regulation, marker-assisted breeding that selects for increased expression alleles, genome editing or genome engineering that employ site-specific DNA modification, screening for naturally occurring variants or induced mutagenized populations or a combination thereof
Polynucleotide sequences encoding a polypeptide represented by one of SEQ ID NOS: 223-284 and polynucleotide sequences represented by one of SEQ ID NOS: 485-547 exhibit reduced expression in plants that have increased and extended expression of Zmm28. Therefore, these sequences and their allelic variants representing about 95% sequence identity to one of SEQ ID NOS: 223-284 and 485-547 are suitable for expression modulation and/or activity modulation to improve agronomic characteristics of maize. This can be achieved by a variety of means, transgenic down-regulation, marker-assisted breeding that selects for reduced expression alleles, genome editing or genome engineering that employ site-specific DNA modification, screening for naturally occurring variants or induced mutagenized populations or a combination thereof.
This example demonstrates identification of several differentially expressed genes in plants expressing Zmm28 transgenically. Transcriptome analysis was conducted to identify differentially-expressed genes (DEGs) and their associated pathways that could provide a possible molecular basis for the previously described increased photosynthesis, N uptake, and plant growth. For simplicity, RNA-seq analysis was focused on V6 leaves from DP202216 and control plants. Results of this analysis identified 192 up-regulated and 64 down-regulated transcripts in DP202216 leaves as compared to the control leaf data (Table 4). CArG box sequences were contained within 3 kb upstream of their promoters in 76% of the DEGs, relative to 26-28% of DEGs from two over-expressed non-MADS transcription factors over a total of four experiments.
In some embodiments, altering expression levels of direct target genes or their protein products/activities thereof (e.g., polypeptides represented by SEQ ID NOS: 23-31 or polynucleotides represented by SEQ ID NOS: 32-39)) may positively affect grain yield. In particular embodiments, altering expression or gene product amounts may change photosynthetic flux. For example, increasing expression of polypeptides represented by SEQ ID NOS: 23-31 may lead to increases in photosynthesis as measured by increased CO2 exchange rate (CER) or electron transport rate. In other examples, expression changes may lead to positive feedback resulting in both increased leaf area with increased light interception and increased photosynthetic rate per leaf area. In yet other examples, expression changes in polypeptides represented by SEQ ID NOS: 23-31 may lead to increased photosynthate and enhanced uptake and assimilation of nitrogen. Increases or decreases in gene expression levels is achieved by introducing a targeted genetic modification or through expression of a recombinant DNA construct. Targeted genetic modifications include for example, removing a repressor element from the regulatory region of the gene or by mutating one or more motifs to increase expression levels of the gene. Enhancer elements can also be introduced to increase gene expression.
In some embodiments, altering gene expression of direct target genes may enhance plant growth. In particular embodiments, altering gene expression may lead to enhanced early vigor or enhanced grain yield. In some embodiments, changes in expression of SEQ ID NO: 30, 38, 563 and/or 564 lead to enhancement of phytohormone reception response leading to increased plant growth or enhanced grain yield.
In some embodiments, altering gene expression of direct target genes may enhance nitrogen uptake or assimilation. In particular embodiments, changes in expression of SEQ ID NO: 39 or related genes such as SEQ ID NO: 566 lead to improvements in nitrogen uptake or assimilation. Such improvements may further lead to enhanced plant growth and/or grain yield.
Increases or decreases in gene expression levels is achieved by introducing a targeted genetic modification or through expression of a recombinant DNA construct. Targeted genetic modifications include for example, removing a repressor element from the regulatory region of the gene or by mutating one or more motifs to increase expression levels of the gene. Enhancer elements can also be introduced to increase gene expression
In some embodiments, altering gene expression of direct target genes may enhance plant stress or disease tolerance. In particular embodiments, changes in expression of SEQ ID NOS: 574-579 results in improvements in biotic or abiotic stress tolerance. In particular embodiments, such expression changes and stress tolerance may lead to enhanced plant vigor, enhanced biomass accumulation and/or enhanced grain yield.
Increases or decreases in gene expression levels to improve plant stress tolerance is achieved by introducing a targeted genetic modification or through expression of a recombinant DNA construct. Targeted genetic modifications include for example, removing a repressor element from the regulatory region of the gene or by mutating one or more motifs to increase expression levels of the gene. Enhancer elements can also be introduced to increase gene expression
Terms used in the claims and specification are defined as set forth below unless otherwise specified. It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise.
All publications and patent applications in this specification are indicative of the level of ordinary skill in the art to which this invention pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated by reference.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Unless mentioned otherwise, the techniques employed or contemplated herein are standard methodologies well known to one of ordinary skill in the art. The materials, methods and examples are illustrative only and not limiting.
Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Units, prefixes and symbols may be denoted in their SI accepted form. Unless otherwise indicated, nucleic acids are written left to right in 5′ to 3′ orientation; amino acid sequences are written left to right in amino to carboxy orientation, respectively. Numeric ranges are inclusive of the numbers defining the range. Amino acids may be referred to herein by either their commonly known three letter symbols or by the one-letter symbols recommended by the IUPAC-IUB Biochemical Nomenclature Commission. Nucleotides, likewise, may be referred to by their commonly accepted single-letter codes.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US19/27617 | 4/16/2019 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62778086 | Dec 2018 | US | |
| 62741529 | Oct 2018 | US | |
| 62659579 | Apr 2018 | US |
