Plants containing the gdhA gene and methods of use thereof

Description

FIELD OF THE INVENTION

The present invention relates to plants transformed with the gdhA gene. More specifically, the present invention relates to a gene which can be used as a selectable marker in transformation. Additionally, the present invention relates to a dual gene herbicide resistance and tolerance package that includes the phosphinothricin acetyl transferase (PAT) gene and/or the Bar gene in combination with the gdhA gene.

BACKGROUND OF THE INVENTION

Plants utilize nitrogen to form organic compounds. Ammonia and ammonium ions do not accumulate in plant cells but instead are rapidly assimilated. Ammonium assimilates through two possible pathways. The first pathway produces glutamate and is catalyzed by glutamate dehydrogenase (GDH), which is found in chloroplasts and mitochondria.

The second pathway for assimilation of ammonia involves a reaction with glutamate to form its amide, glutamine. This reaction is catalyzed by glutamine synthase (GS) and requires energy in the form of ATP. Glutamine is then catalyzed by glutamate synthase (GOGAT) to form glutamate. GS appears in chloroplasts and cytosol in leaves and roots, whereas, GOGAT is in leaf chloroplasts and plastids in roots.

Although both pathways result in glutamate, the second pathway appears more important in ammonium assimilation in plants. Glutamate dehydrogenase, the enzyme of the first pathway, has a high Km value. This value which is the concentration of ammonia where half of the enzyme maximum operation rate is within levels which are toxic for plant cells. In contrast, the GS Km value is much lower. Additionally, radioactive labeling of NO

3

or NH

4

show labeled nitrogen in the amide group of glutamine first.

Although GS has a high affinity for ammonia and GDH has a lower affinity, GS has low specific activity per enzyme molecule and GDH has high specific activity per molecule.

Ammonium assimilation pathways of plants and microorganism; although maybe not fully understood; have been known. In October of 1980, the ICI Agricultural Division published in

Nature

, Volume 287, page 396 an article on improved conversion of methanol to single cell protein by

Methylophilus methylotropus.

The researchers cloned the glutamine dehydrogenase gene of

Escherichia coli

(

E. coli

) into a mutant of

Methylophilus methylotropus

organism that lacks GOGAT. The paper explained that the GDH pathway should result in the organism consuming less energy. The researchers speculate that potential industrial or agricultural savings could be made by identification of features that incur “energy penalty” and this is an exciting area for recombinant DNA. This organism to organism transfer of the

E. coli

GDH gene should substantially decrease in enzyme activity thus a plasmid with a high copy number was used.

In 1988, the expression of

E. coli

glutamate dehydrogenase in cyanobacterium was reported in

Plant Molecular Biology

, Volume II, pages 335-344. Cyanobacterium that lacked glutamate dehydrogenase were transformed with the gdhA gene of

E. coli

and levels of NADP-specific glutamate dehydrogenase activity resulted in the transformed microorganism. The authors speculate that it would be interesting to investigate the engineering of glutamate dehydrogenase activity to higher plants and to study in detail the possible roles for glutamate dehydrogenase activity in ammonium detoxification.

Although there was some speculation on nitrogen assimilation genes in higher plants, in a paper on nitrogen assimilatory genes in

The Genetic Manipulation of Plants and its Application to Agriculture

, at page 109, the authors state that it would be tempting to suggest that crop plants might show increased metabolic efficiency if ammonium assimilation was channeled through glutamate dehydrogenase. But the authors clearly list the number of technological barriers to this. There remained a number of barriers to this research including the potential negative consequences of uncontrolled expression in the plant. The authors reluctantly conclude “perhaps” there may be some benefit in replacing glutamate synthase, with ammonium—utilizing alternatives.

In

Molecular and General Genetics

in 1993 in volume 236, pages 315-325, the modulation of glutamine synthetase gene expression in tobacco was reported. An alfalfa gene was placed in the tobacco plant cells in the sense and antisense position. Partial inhibitation in the antisense position was seen without a true homologous gene.

In 1994, it was reported that increasing the activity of plant nitrogen metabolism enzymes may alter plant growth, development and composition. Increased yield and protein content as well as reduced levels of nitrogen in agricultural runoff water and food may result. Plant nitrogen metabolism has been altered by transformation with a highly active assimilatory bacterial glutamate dehydrogenase gene, plant glutamate dehydrogenase is less active in ammonium gene has been altered by PCR and PCR strand overlap exchange to modify coding region and allow high levels of expression in plant cells. The 5′ non-coding region has been altered to increase translation and permit protein targeting to either cytosol or chloroplasts. The 3′ non-coding region has been altered to stabilize the mRNA and ensure appropriate polyadenylation of the mRNA. Certain codons likely to inhibit expression to high levels in plant cells have been altered. The effects of the various sequence substitutions on gene expression in plant cells compared to the unmodified gene will be reported. This abstract is reporting on speculation of the researchers as the abstract clearly reference what may happen or codons that are likely to inhibit. The abstract appears to provide a guess as to what might happen, not something that has been done.

Although researchers speculated that the gdhA gene may be useful in higher plants, the drawbacks and possible disruption of the photosynthesis pathway lead researchers to the belief that the potential use was probably not possible due to technical barriers. Even the inventor was only speculating on the potential of the gdhA gene to avoid ammonia toxification.

There remains a need to transform cereals to determine if the gdhA gene would have any effect on the plant in either nontoxifying levels or toxic levels of ammonia. The usefulness of the gene as a tolerance mechanism for certain herbicides was not proven prior to this. This gene is tolerant to phosphinothricin which can include glufosinate and other similar herbicidally active derivatives, salts, and acids thereof. The combination of this gdhA gene with other selectable markers to increase plant resistance to herbicide damage was heretofore undiscovered. The ability of a plant to increase dry weight due to increased nitrogen uptake in even nontoxic levels of ammonia was not realized or considered until the present invention.

The composition of proteins, sugars, starch, cellulose and structural lipids, storage lipids and oils can be altered by increasing or decreasing nitrogen supply to the plant. The question remains if the supply of nitrogen is at a high level can the composition of proteins, sugars, starch, cellulose, lipids and oils be modified by the addition of the gdhA gene. The present invention clearly indicates that the protein content in seeds and leaves is altered. Although the gdhA gene may have had some suggested potential to assimilate additional nitrogen in highly toxic nitrogen conditions, the gdhA genes result GDH enzyme has a weaker ammonium affinity than the ATP specific GS. At lower ammonium concentrations assimilation by GDH was expected to be limited due to its lower ammonium affinity and the reversibility of its reaction. Thus, it was surprising and unexpected that the gdhA gene when in a plant produced measurable changes in the number of leaves and protein content of the leaves and the seeds, the dry weight of the plant even in soils having normal ammonium levels. At these levels, the expectation would be that the GS/GOGAT cycle would be the active cycle.

SUMMARY OF THE INVENTION

An object of this invention is to provide transformed plants containing the gdhA gene that evidences increased plant biomass.

Another object of this invention is to provide transformed plants that increases leaf size.

Still another object of this invention is to provide transformed corn plants that are resistant to PPT.

Yet a different object of this invention is to provide a corn plant with dual gene resistance to PPT in the GS and the GDH pathways.

Furthermore, an object of the present invention is to provide altered plant growth and yield in seed crops including sunflower, corn, soybeans and canola (brassica).

Additionally, the object of the present invention is to provide a gdhA transformed corn plant that contains a gene that alters the composition of the makeup of the corn seed.

Broadly, then the present invention includes a method of improving crop growth by applying to a field containing a crop, which are phosphinothricin resistant due to having an expressible transgene encoding for phosphinothricin resistant glutamate dehydrogenase enzyme, a sufficient amount of a phosphinothricin class herbicide to control undesirable vegetation without significantly affecting crop growth.

This method includes a gene which is mutagenized, and a gene which is a modified bacterial gene. The gene can contain the Kozac consensus sequence in a particular embodiment. This method, of course, can include instances where the phosphinothricin class herbicide is combined with a second herbicide and then applied to the transformed crop.

The method includes transformed crops which are selected from the group consisting of corn, cotton, brassica, soybeans, wheat or rice. Some of these crops are naturally resistant and the addition of the gdhA allows additional heartiness during herbicide application.

This invention is not just about the method described about. This invention also includes within its broad scope. Transgenic plant cells and progeny having expression cassettes with a transcription initiation region functional in the plant cells, a DNA sequence that encodes for the GDH enzyme in said plant cells, and a transcription termination region functional in the plant cells. The expression cassette then imparts to the plant a detectable level of herbicide resistance to the phosphinothricin class of herbicides.

In the cells at least one of the transcription region or the termination region is not naturally associated with the gdhA sequence. The invention encompass these cells wherein the sequence is from a bacterial gene preferably from

E. coli

. In some embodiments these cells, including a sequence from the bacterial gene, are modified to enhance expression in plant cells. The cells, plants and progeny include a DNA sequence that encodes the amino acid sequence shown in FIG.

3

.

To enhance amino acid production, the cells can include a chloroplast transient peptide adapted to target the chloroplasts. In other embodiments, cells have a transcription initiation region which is constitutive in action or can be organ or tissue specific.

The present invention includes cell culture of cells that contain a marker gene that is capable of growth in a culture medium which includes a herbicide which is in the phosphinothricin class. The herbicide includes bialaphos, LIBERTY glufosinate, and IGNITE glufosinate. Additionally, the present invention includes a cell culture of cells having a gene resistant to the PPT and a marker gene that is capable of growth in a culture medium which includes a herbicide which is not a phosphinothricin class herbicide.

The invention includes a transgenic plant originally formed from nontransgenic plants and progeny thereof which contains an expression cassette having a transcription initiation region functional in the plant cell, a genetically engineered DNA sequence that is capable of encoding for the GDH enzyme in the plant cells wherein the plant evidences detectable alteration in GDH activity when compared to the nontransgenic plants like that from which the transgenic plant was formed. The alteration in GDH activity could be increased activity or decreased activity. The transgenic plant can be a dicot or a monocot. Of particular interest are transgenic

Zea mays

plants. Alternatively, the transgenic plant can be selected from a group consisting of brassica, cotton, soybeans, and tobacco. The change in the nitrogen assimilation pathway allows other parts of the plant to be altered.

The invention includes a transgenic plant that forms seeds and has genetically engineered DNA sequences that alters the oil content of the seed of the plant and evidences altered GDH activity when compared to a transgenic plant containing only the oil altering DNA sequence.

The invention covers a transformed corn plant containing a bacterial glutamate dehydrogenase gene. Additionally, this plant can contain a second gene that was introduced into the plant or its ancestors by genetic engineering that is resistant to PPT.

The invention broadly covers a recombinant plasmid characteristic in that the recombinant plasmid contains a constitutive promoter, a chloroplast transit peptide and the bacterial gdhA gene and a transcriptional termination region. A biologically pure culture of a bacterium characterized in that the bacterium is transformed with the recombinant plasmid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

shows the DNA sequence of the gdhA gene (SEQ ID NO:1) of

E. coli.

FIG. 2

shows the forward primer (panel A, SEQ ID NO:3) at 5′ and the reverse primer (panel B, SEQ ID NO:4) at 3′ of the non-coding regions (panel A, SEQ ID NOS:5-7, panel B, SEQ ID NOS:8-10) of the gdhA gene.

SacI and XbaI restriction enzyme sites are indicated as is the sequence modification to introduce Kozac's consensus sequence (double underline). The bold portion was eliminated as an in RNA destabilizing sequence.

FIG. 3

shows the amino acid sequence (SEQ ID NO:11) of

E. coli

GDH enzyme expressed in both the tobacco and corn.

FIG. 4

shows a linear map of the plasmid vector pBI121:GDH1 developed in Example I. The plasmid has the uidA gene removed and the gdhA gene inserted.

FIG. 5

shows a circular map of the plasmid vector pUBGP1 used in the examples as starting material and a control for plasmids useful in

Zea mays.

FIG. 6A

shows the DNA (SEQ ID NO:12) sequence of the mutagenized gdhA gene used for plant expression (tobacco and corn).

FIG. 6B

shows the DNA sequence (SEQ ID NO:13) including the SphI site of the mutagenized gdhA gene used for plant expression (tobacco and corn).

FIG. 7A

shows the mutagenized gdhA gene (SEQ ID NO:14) with the added restriction sites for use in

Zea mays.

FIG. 7B

shows a linear plasmid map of pBI 121::SSU::GDH1.

FIG. 8

shows the 3′ EcoRI SphI adapter (SEQ ID NOS:15-16) between nosT and plasmid for corn transformation.

FIG. 9

shows a circular map of the plasmid pUBGDH1 wherein UB is ubiquitin.

FIG. 10

shows a circular map of the plasmid vector PUBGDHI with the pre SS unit.

FIG. 11

shows the methylammonium uptake of tobacco transformants.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to methods of producing transgenic plants containing the gdbA gene. The term transgenic plant refers to plants having exogenous genetic sequences which are introduced into the genome of a plant by a transformation method and the progeny thereof.

Transformation Methods—are means for integrating new genetic coding sequences by the incorporation of these sequences into a plant of new genetic sequences through man assistance.

Though there are a large number of known methods to transform plants, certain types of plants are more amenable to transformation than are others. Tobacco is a readily transformable plant. The basic steps of transforming plants are known in the art. These steps are concisely outlined in U.S. Pat. No. 5,484,956 “Fertile Transgenic

Zea mays

Plants Comprising Heterologous DNA Encoding Bacillus Thuringiensis Endotoxin” issued Jan. 16, 1996 and U.S. Pat. No. 5,489,520 “Process of Producing Fertile

Zea mays

Plants and Progeny Comprising a Gene Encoding Phosphinothricin Acetyl Transferase” issued Feb. 6, 1996.

1. Plant Lines

Plant cells such as maize can be transformed by a number of different techniques. Some of these techniques which have been reported on and are known in the art include maize pollen transformation (See University of Toledo 1993 U.S. Pat. No. 5,177,010); Biolistic gun technology (See U.S. Pat. No. 5,484,956); Whiskers technology (See U.S. Pat. Nos. 5,464,765 and 5,302,523); Electroporation; Agrobacterium (See 1996 article on transformation of maize cells in

Nature Biotechnology

, Volume 14, June 1996) along with numerous other methods which may have slightly lower efficiency rates then those listed. Some of these methods require specific types of cells and other methods can be practiced on any number of cell types.

The use of pollen, cotyledons, meristems and ovum as the target issue can eliminate the need for extensive tissue culture work. However, the present state of the technology does not provide very efficient use of this material.

Generally, cells derived from meristematic tissue are useful. Zygotic embryos can also be used. Additionally, the method of transformation of meristematic cells of cereal is also taught in the PCT application WO96/04392. Any of the various cell lines, tissues, plants and plant parts can and have been transformed by those having knowledge in the art. Methods of preparing callus from various plants are well known in the art and specific methods are detailed in patents and references used by those skilled in the art.

Cultures can be initiated from most of the above identified tissue. The material used herein was zygotic embryos. The embryos are harvested and then either transformed or placed in media. Osmotic cell treatments may be given to enhance particle penetration, cell survival, etc.

The only true requirement of the transformed material is that it can form a fertile transformed plant. This gene can be used to transform a number of plants both monocots and dicots. The plants that are produced as field crops are particularly useful. These crops can include cotton, corn, soybeans, wheat, sorghum, brassica, sunflower and some forage grasses and vegetables. The cereal grains appear to have the most economic advantage presently. The gdhA gene can come from various non-plant genes (such as; bacteria, yeast, animals, viruses). The gdhA gene can also come from plants. The gene insert used herein was either an

E. coli

glutamate dehydrogenase gene or a mutagenized version thereof. Another gdhA gene of particular interest is from Chlorella.

The DNA used for transformation of these plants clearly may be circular, linear, double or single stranded. Usually, the DNA is in the form of a plasmid. The plasmid usually contains regulatory and/or targeting sequences which assists the expression of the gene in the plant. The methods of forming plasmids for transformation are known in the art. Plasmid components can include such items as: leader sequences, transit polypeptides, promoters, terminators, genes, introns, marker genes, etc. The structures of the gene orientations can be sense, antisense, partial antisense, or partial sense: multiple gene copies can be used.

The gdhA gene can be useful to change or alter the nitrogen assimilation pathway or to assist in the identification and/or heartiness of transformed material in the presence of herbicide. Clearly, the bar gene from

Streptoinycin hygroscopicus

which encodes phosphinothricin acetyl transferase is resistance to phosphinothricin, and bialaphos herbicides (see U.S. Pat. No. 5,484,956, Table 1). Thus, this gene is useful as a selectable marker gene.

Surprisingly, the present gene is tolerant to some levels of phosphinothricin (including glufosinates) and bialaphos though in the constructs tested, the present gene may evidence slightly more susceptibility to herbicide damage at high herbicide concentration then plants transformed with the bar and PAT genes. However, when the gdhA gene is combined with the PAT and/or bar gene, the transformed cells and/or plants have increased regenerability and heartiness after herbicide selection, particularly to Ignite.

The regulatory promoters employed in the present invention can be constitutive such as CaMv35S for dicots and polyubiquitin for monocots or tissue specific promoters such as CAB promoters, etc. The prior art promoter include but is not limited to octopine synthase, nopaline synthase, CaMv19S, mannopine synthase. These regulatory sequences can be combined with introns, terminators, enhancers, leader sequences and the like in the material used for transformation.

The isolated DNA is then transformed into the plant. Many dicots can easily be transformed with Agrobacterium. Some monocots are more difficult to transform. As previously noted, there are a number of useful transformation processes. The improvements in transformation technology are beginning to eliminate the need to regenerate plants from cells. Since 1986, the transformation of pollen has been published and recently the transformation of plant meristems have been published. The transformation of ovum, pollen, and seedlings meristem greatly reduce the difficulties associated with cell regeneration of different plants or genotypes within a plant can present.

The most common method of transformation is referred to as gunning or microprojectile bombardment. This biolistic process has small gold coated particles coated with DNA shot into the transformable material. Techniques for gunning DNA into cells, tissue, callus, embryos, and the like are well known in the prior art.

After the transformation of the plant material is complete, the next step is identifying the cells or material which has been transformed. In some cases, a screenable marker is employed such as the beta-glucuronidase gene of the uidA locus of

E. coli

. Thus, the cells expressing the colored protein are selected for either regeneration or further use. In many cases, the transformed material is identified by a selectable marker. The putatively transformed material is exposed to a toxic agent at varying concentrations. The cells which are not transformed with the selectable marker that provides resistance to this toxic agent die. Cells or tissues containing the resistant selectable marker generally proliferate. It has been noted that although selectable markers protect the cells from some of the toxic affects of the herbicide or antibiotic, the cells may still be slightly effected by the toxic agent by having slower growth rates. The present invention is useful as a selectable marker for identifying transformed materials in the presence of the herbicide phosphinothricin. In fact, when combined with the PAT or bar gene which is known to give resistance to phosphinothricin, the cells or plants after exposure to the herbicide often evidences increased growth by weight and appear more vigorous and healthy.

If the transformed material was cell lines then these lines are regenerated into plants. The cell's lines are treated to induce tissue differentiation. Methods of regeneration of cellular material are well known in the art since early 1982. The plants from either the transformation process or the regeneration process are transgenic plants.

The following non-limiting examples are shown to more particularly describe the present invention.

The DNA sequence of the

gdhA

gene of

Escherichia coli

which encodes a 447 amino acid polypeptide subunit of NADP-specific glutamate dehydrogenase was presented in 1982 in Nucleic Acids Research, Volume II, Number 15, 1983. The present examples will illustrate the gdhA gene transformed into both dicot and monocot plants.

EXAMPLE I

Fertile transgenic tobacco plants containing an isolated gdhA gene was prepared as follows:

A. The Tobacco Tissue for Transformation was Initiated and Maintained.

Seed from

Nicotiana tabacum

var. Petite Havana were surface sterilized and germinated on MSO medium (Murashige and Skoog 1962). Two weeks after germination, leaves were excised and used in transformation experiments.

B. Formation of the Plasmid.

A bacterial glutamate dehydrogenase (gdhA) gene, shown in

FIG. 1

(SEQ ID NO:1), derived from

E. coli

, was altered for expression in plant cells by polymerase chain reaction. The 5′ non-coding region was modified by the introduction of an XbaI restriction enzyme site. Kozac's consensus sequence (Lutcke et. al. 1987) was also added to the 5′ region (SEQ ID NOS:5-7) to allow high levels of expression in plant cells. The 3′ non-coding region (SEQ ID NOS:8-10) was altered to stabilize the mRNA and ensure appropriate polyadenylation and a SacI restriction site was added. These primer sequences, shown in

FIG. 2

(SEQ ID NOS:3-4), are the introduction of the restriction sites and the Kozac's consensus sequence along with the destabilizing portions. The amino acid sequence of the gdhA gene was retained. PCR was carried out in an automated thermal cycler (MJ Research, St. Louis, Mo.) for 25 cycles (each cycle consisting of 1 min. at 92° C., 1 min. at 60° C. and 3 min. at 72° C). Reactions contained 200 ng of pBG1 (Mattaj et. al. 1981), 0.9 mM) MgCL

2

, dNTPs, 1 unit of Taq polymerase (Promega, Madison, Wis.) and 1 nM of each primer. The PCR products were gel purified and DNA bands recovered from agarose gels using GeneClean (Bio101, Hercules, Calif.). XbaI and SacI were used with the band which was digested. This process provided single strand complementary end for ligation into a vector.

The uidA gene from pBI121.1 (pBI121 plasmid is commercially available from Clontech Laboratories, Palo Alto, Calif.), (Jefferson, 1987) was removed by restriction digest with XbaI and SacI and the gel eluted PCR products were ligated into the resulting 9.7 kb fragment of pBI121.1. The amino acid sequence of the GDH enzyme produced by the gdhA gene is shown in (SEQ ID NO:11) FIG.

3

. The plasmids were then transformed into competent

E. coli

cells (Top10 Invitrogen, San Diego, Calif.) via electroporation. Colony hybridization was used to detect colonies with the modified gdhA inserts (FIG.

3

). Plasmids from the hybridizing colonies were used to transform competent Agrobacterium tumefaciens (Sambrook et. al. 1989) strains LBA4404 (Hooykas 1981) and EHA101 (Nester 1984).

C. Plant Transformation.

Nicotiana tabacum

var. Petite Havana leaf discs from in vitro grown seedlings were transformed with the

A. tumefaciens

constructs using standard tobacco transformation procedures (Horsch et. al. 1988) with the following modification. Transformed shoots were selected on 300 μg/ml kanamycin. Shoots were excised and rooted in a sterile peat-based medium in GA7 vessels (Magenta Corp. Chicago, Ill.). The vessel lids were gradually removed (over 7-10 days) to acclimatize the plantlets to laboratory conditions before placement in the greenhouse.

D. Confirmation of Transformation with gdhA Gene.

To show that the tobacco has acquired the gdhA gene the specific activity of GDH was quantified by measuring the rate of oxidation of NADPH due to 2-oxoglutamate reductive amination. This enzyme assay was performed on cell free extracts.

1. Cell Free Extract Preparation

Leaf tissue (1-2 g) was placed in 5 volumes of ice-cold buffer(200 mM Tris-HCL pH8.0, 14 mM).

2. Mercaptoethanol, 10 mM L-cysteine, 0.5 mM phenylmethylsulphonylfluroide, 0.5% (v/v) Triton x-100) [23]. Tissue was homogenized by Polytron (Tekmar, Cincinnati, Ohio) 4 times for 12 seconds each and was returned to an ice bath for 12 seconds between each grind. The slurry was centrifuged at 10,000 g for 25 minutes and the supernatant was used for enzyme assays.

E. coli

extracts were prepared as in Mountain et. al., 1985 [32]. This publication is hereby incorporated by reference. All steps were carried out at 4° C.

Gel Analysis and GDH Activity Staining

Regenerants were qualitatively tested for deaminating NADP-dependent GDH activity following gel electrophoresis of crude protein extracts after Lightfoot et. al., 1988. Electrophoresis of other protein extracts is known to those skilled in the art. Proteins were separated on a non-denaturing gel containing 5% polyacrylamide by electrophoresis for 2 hr at 120 V. NADP-specific GDH enzyme activity was visualized as a band in the gel by L-glutamate and NADP-dependent tetrazolium staining of GDH isozymes (50 mM Tris pH 9.3, 8 mg/ml glutamate, 0.04 mg/ml NADP, 0.04 mg/ml MTT, 0.04 mg/ml phenazine monosulphate and 0.08 mg/ml CaCl

2

).

Enzyme assays

The specific activity of aminating NADPH-dependent GDH in cell free extracts was quantified by measuring the rate of oxidation of NADPH attributable to the reductive amination of 2-oxoglutarate. The reaction mixture initially consisted of 0.1 M Tris pH 8.5, 0.2M 2-α-ketoglutarate, 1.0 MM CaCl

2

, 0.2 mM NADPH, 200 mM ammonium chloride and 50 mM glutamine. The rate of change in absorption was measured at 340 nm for 1.5 minutes before and 1.5 minutes after the addition of the 20 mM or 200 mM ammonium chloride. Glutamine was then added to 5 mM and the absorbance measured for a further 1.5 minutes. Assays were performed at 25° C.

Glutamine synthetase activity was measured spectrophotometrically by incubating the crude extract in a reaction mixture for 10 minutes by the transferase assay as taught in the art (see Cullinore J. V.

Planta

150.39 2-396, 1980). The OD

500

was measured, 1 μM γ-glutamyl hydroxamate has an OD

500

of 0.4.

Glutamate concentration determination

Glutamate and glutamine concentrations were determined after separation on Dowex-1-acetate. Quantitation was by the ninhydrin spectrophotometric assay.

TABLE 1

Characteristics of Transgenic Plants

Number of Lines

Explants

Antibiotic

Strain/Gene

Inoculated

Resistant

a

GDH

+b

EHA101/gdhA

30

17

12

LBA4404/gdhA

30

2

2

a

= Resistant to 300 μg/ml kanamycin in an R

1

seedling assay.

b

= Positive bands after electrophoresis of crude extract on 5% polyacrylamide gel followed by NADP-dependent tetrazolium staining of GDH isozymes.

EXAMPLE II

The original plant transformation vector pBI121.1 was modified in Example I to contain the gdhA gene. In this example, the vector was unchanged and pBI121.1 containing uidA was used as the chimeric plasmid which was transformed into

E. coli

cells (Top10 Invitrogen, San Diego, Calif.) via electroporation. Colony hybridization was used to detect colonies with plasmids containing uidA gene. Plasmids from the hybridizing colonies were analyzed by single and double restriction digestions. Plasmids with the correct physical map were used to transform competent

Agrobacterium tumefaciens

strains LBA4404 and EHA101.

Plant Transformation.

Nicotiana tabacum

var. Petite Havana leaf discs from in vitro grown seedlings were transformed with the

A. tumefaciens

constructs using standard tobacco transformation procedures as in the earlier example with the following modification. Transformed shoots were selected on 300 μg/ml kanamycin. Shoots were excised and rooted in a sterile peat-based medium in GA7 vessels (Magenta Corp. Chicago, Ill.). The vessel lids were gradually removed (over 7-10 days) to acclimatize the plantlets to laboratory conditions before placement in the greenhouse. The R

0

plants were allowed to flower and self fertilize to produce the R

1

seed. R

1

seed were collected from individual plants and stored at 4° C.

TABLE 2

Characteristics of uidA

Number of Lines

Explants

Antibiotic

Strain/Gene

Inoculated

Resistant

a

GDH

+b

LBA4404/uidA

15

2

0

EHA101/uidA

15

4

0

a

= Resistant to 300 μg/ml kanamycin in an R

1

seedling assay.

b

= Positive bands after electrophoresis of crude extract on 5% polyacrylamide gel followed by NADP-dependent tetrazolium staining of GDH isozymes.

Discussion of Examples I and II.

A non denaturing polyacrylamide gel containing bands produced from NADP-dependent staining of crude extracts of

E. coli

, gdhA transformed lines and one uidA line was performed and read. As expected, the uidA transformed line did not produce bands when stained with NADP

+

as the oxidant. Fourteen of the 19 antibiotic resistant gdhA transformants showed GDH activity as did the

E. coli.

TABLE 3

Specific activity of NADPH-dependent GDH and ATP

dependent GS in cell-free extracts of transgenic tobacco

GDH Activity

NADPH

Tobacco

Transforming

Oxidation

GS activity

Line

Gene

nM/mg

a

/min

nM/mg/min

2A

gdhA

2046

38

8

2

gdhA

1600

71

9

1

gdhA

1063

85

7B

uidA

0

85

E. coli

gdhA

215

59

a

= Specific activity per mg of soluble protein.

Enzyme Specific Activity of Examples I and II.

High specific activities of GDH in gdhA transformed R

0

tobacco leaves were observed. The gdhA transformed tobacco lines produced up to 10 times more activity than gdhA in

E. coli

. NADP-specific GDH activity was not detectable in the uidA transformed tobacco lines.

GS activity was somewhat reduced in leaves of plant lines where the GDH activity was more than about 1100 nM/mg protein/min. The GDH activity was about 15-50 fold greater than the GS activity in the cell free extracts with saturating substrate concentrations. The GDH activity was not greatly reduced in assays containing 20 mM ammonium (data not shown) close to physiological NH

4

concentrations. Therefore, gdhA transformed plants may be assimilating ammonium at a rate equivalent to, or better than, GS.

The specific activity of GDH in cell free extracts show gdhA gene in plants at 5-10 times the

E. coli

gdhA activity. This was surprising as there was initially some question as to whether the bacterial gene would express well in the plant genome. The gdhA gene in plants have a GDH activity that is 15-50 times greater than the GS activity. Increased ammonium assimilation is apparently provided by GDH activity if substrate concentrations are not limiting.

Ammonium assimilation by GDH is energetically favorable compared to GS since there is a net saving of one ATP. In addition, the higher specific activity of GDH might require the synthesis of 10 fold fewer enzyme molecules per mole of ammonium assimilated.

EXAMPLE III

Fertile transgenic tobacco containing gdhA gene and chloroplast transit peptides:

The plasmid constructed in Example I (shown in

FIG. 4

) does not target the gdhA gene to the area of tissue that it is presumed to be most helpful. The chloroplasts of the plant tissue is targeting in the present example. The pBI121 gdhA plasmid was modified to allow fusion with cleavable preprotein sequences (often referred to as chloroplast transit peptide sequences) from RUBISCO SSU (rbcS) by introduction of the SphI site.

PCR amplification of gdhA from pBI121::GDH1 using the mutagenic primer.

Primer SPHGDH5 (SEQ ID NO:17)

GGT TTT ATA TgC ATg CAT CAg ACA TAT TC 5′ SphI adapter for ligation of gdhA with chloroplast targeting pre-peptide encoding sequences.

And the addition of the specific primer HUGDH3 (shown in

FIG. 6B

) was completed. The amplified 1.3 kbp fragment was subject to restriction digestion with SphI and SacI. Digestion of pBI121 with SmaI and SacI allowed recovery of the vector minus GUS (uidA) as a 9.6 kbp fragment. PCR amplification from the plasmid pPSR6 (Cashmore et. al., 1983) and restriction digestion allowed recovery of the preprotein encoding sequence as a 0.2 kbp fragment SmaI to SphI fragment. The 9.6 kbp pBI121 fragment was ligated with the 1.3 kbp fragment from pBI121::GDH1 and the 0.2 kbp fragment from pPRS6 to give pBI121::SSU::GDH1 (shown in

FIG. 7

) which was amplified in

E. coli

DH5.

Results of Examples

The transformed tobacco plants, leaves and seed Examples I and II were analyzed for percentage of nitrogen, protein and crude fat with the following result:

TABLE 4

Tobacco Leaf Analysis

% N

% Protein

uidA transformed

6.98

43.6

gdhA transformed

8.01

50.0

Tobacco Seed Analysis

% N

% Protein

Crude Fat

uidA transformed

4.2

26.5

36.9

gdhA transformed

3.56

22.0

35.07

nontransformed

3.98

25.0

38.5

The leaf analysis shows a 1% nitrogen increase and a 6% increase in protein in the gdbA transformed plant. The seed analysis appears to indicate that the gdhA gene may be altering the accumulation of nitrogen, protein and crude fat in the tobacco seed.

EXAMPLE IV

Ammonium Toxicity

The transformed tobacco seeds of the previous examples were used in an ammonium toxicity study. Ammonium toxicity was measured by germinating transformed tobacco seed on agar solidified MS media while excluding all nitrogen sources except ammonium chloride. The medium was supplemented with 10, 30, 50, 70 or 100 mM ammonium chloride but no nitrates. The seedlings were grown either with or without 30 mg/1 sucrose. Ten to fifteen R

1

seeds were initiated per plate with four replications per concentration. Fresh and dry weights of 10 seedlings per plate were measured after six weeks on these media. Table 5 shows these results.

TABLE 5

Effect of concentration of ammonium chloride and genotype on dry weight

of gdhA or uidA transformed R

1

tobacco seedlings. No carbon source supplied.

Dry weight (mg) of Transformed Lines

2A

8

2

9

1

7B

LSD

c

values

NH4 Conc.

(gdhA)

n

a

(gdhA)

n

(gdhA)

n

(uidA)

n

Significance

b

5%

1%

10 nM

0.75

40

1.3

29

0.48

39

0.85

20

**

0.25

0.33

30

1.2

34

0.8

36

0.57

36

0.6

39

**

0.31

0.40

50

0.6

30

0.36

39

0.38

28

0.4

38

**

0.14

0.19

70

0.36

39

0.35

40

0.21

40

0.25

38

**

0.08

0.11

100

0.19

36

0.18

29

0.14

40

0.17

40

**

0.06

0.07

Significance

**

**

**

**

LSD value

5%

0.28

0.21

0.10

0.10

1%

0.36

0.28

0.13

0.14

a

n = number of seedlings

b

** = significant results at the 1% level, NS = nonsignificant

c

LSD = Lease Significant Difference as calculated by T

df

(MSE/n)

1/2

Increased resistance to ammonium chloride is partial as the GDH activity would affect primarily the nitrogen assimilation rate. Increased resistance to ammonium chloride is evident by the increase in fresh and dry weight accumulated by the gdba transformed lines.

EXAMPLE V

Field Traits of Transgenic Tobacco

The transformed tobacco was planted in a field and fertilized with 150 lb. per acre of ammonium nitrate. The following data on the field traits was collected.

TABLE 6A

(150# per Acre of Nitrogen)

gdhA transformed

Nicotina tabaccum

variety ‘Petite Havana’ lines 913 & 2A1,

uidA transformed line 7B1 and bar transformed line BAR were grown under field conditions

in a completely randomized block design. Data were collected after 12 weeks on height,

# of leaves and length and width of the most recent fully expanded leaf.

Plants were harvested at ground level and dried for 3 days to determine dry weight (DWT.).

Line

DWT

n

Height

a

n

# of Leaves

b

n

Length

c

n

Width

d

n

e

2A1

23.78

5

37.3456

90

17.167

90

23.1689

90

11.786

90

913

28.74

5

41.2224

85

13.765

85

24.9012

85

13.415

85

7B1

19.18

5

41.4822

90

13.556

90

24.1311

90

13.21

90

Bar

10.3

5

36.16

82

13.585

82

22.5159

82

13.794

82

Sig.

f

0.0393

0.0001

0.0001

0.0001

0.2477

LSD

.05

12.34

1.597

2.17

1.147

2.198

a

height was measured to the top of the most recent fully expanded leaf

b

the number of leaves greater than 10 cm

c

the length of the most recent fully expanded leaf was measured

d

the width of the most recent fully expanded leaf was measured

e

n = number of replications

If the control is the uidA gene in the transformed tobacco plants then the significant differences are in the leaf number and the leaf length between the 91 line and the 7B line. The Bar data across the chart, with the sole exception of the nitrogen content, is lower then the 7B line. It is within the LSD. If Bar is used as the control, dry weight and plant height (yield) is also significantly greater for Line 91. Clearly, increasing leaf number and leaf length is of increased value when that portion of the plant is part of what is harvested. For example, this increased biomass is important in silage, and forage grasses such as alfalfa, clover and the like.

TABLE 6B

(150# per Acre of Nitrogen)

Means Analysis

gdhA transformed

Nicotina tabaccum

variety ‘Petite Havana’ lines 913 & 2A1,

uidA transformed line 7B1 and bar transformed line BAR were grown under field conditions

in a completely randomized block design. Data were collected after 12 weeks on height,

# of leaves and length and width of the most recent fully expanded leaf.

Plants were harvested at ground level and dried for 3 days to determine dry weight (DWT.).

Line

DWT

n

Height

a

n

# of Leaves

b

n

Length

c

n

Width

d

n

e

2A1

209.8

6

56.7

6

58.1

6

30.8

6

17.5

6

913

223.1

6

55

6

61.8

6

31.8

6

18.2

6

7B1

204.3

6

57.9

6

39.3

6

27

6

14.7

6

Bar

203.4

6

59.2

6

48.4

6

29.4

6

16.8

6

Sig.

f

0.589

0.3498

0.0145

0.0087

0.0072

LSD

.05

13.9

2.64

1.9

a

height was measured to the top of the most recent fully expanded leaf

b

the number of leaves greater than 10 cm

c

the length of the most recent fully expanded leaf was measured

d

the width of the most recent fully expanded leaf was measured

e

n = number of replications

TABLE 6C

(75# per Acre of Nitrogen)

Means Analysis

gdhA transformed

Nicotina tabaccum

variety ‘Petite Havana’ lines 913, 2A1,

uidA transformed line 7B1 and bar transformed line BAR were grown under field conditions

in a completely randomized block design. Data were collected after 12 weeks on height,

# of leaves and length and width of the most recent fully expanded leaf.

Plants were harvested at ground level and dried for 3 days to determine dry weight (DWT.).

Line

DWT

n

Height

a

n

# of Leaves

b

n

Length

c

n

Width

d

n

e

2A1

190.9

6

57.2

6

46.8

6

29.1

6

16.4

6

913

189.9

6

56.8

6

49.3

6

28.8

6

16.4

6

7B1

165.6

6

57.2

6

26.2

6

24.6

6

13.3

6

Bar

185.5

6

54

6

44.8

6

27.7

6

15.7

6

Sig.

f

0.058

0.3261

0.0048

0.0024

0.0007

LSD

.05

20.17

12.38

2.2

1.39

a

height was measured to the top of the most recent fully expanded leaf

b

the number of leaves greater than 10 cm

c

the length of the most recent fully expanded leaf was measured

d

the width of the most recent fully expanded leaf was measured

e

n = number of replications

TABLE 6D

Combined Data

(150# per Acre of Nitrogen)

gdhA transformed

Nicotiana tabaccum

variety ‘Petite Havana’ (GDH+) and GDH− Nicotiana

were grown under field conditions in a completely randomized block design. Data were collected

after 12 weeks on height, # of leaves and length and width of the most recent fully expanded leaf.

Plants were harvested at ground level and dried for 3 days to determine dry weight (DWT.).

Line

Dry Weight

n

Height

a

n

# of Leaves

b

n

Length

c

n

Width

d

n

e

GDH+

130.01

22

41.3

494

20.15

494

24.7

494

13.13

494

GDH−

117.87

22

41.16

450

16.8

450

23.8

450

13.69

450

Sig.

f

0.6944

0.9467

0.012

0.0091

0.4054

LSD

.05

2.614

0.6957

1.339

a

height was measured to the top of the most recent fully expanded leaf

b

the number of leaves greater than 10 cm

c

the length of the most recent fully expanded leaf was measured

d

the width of the most recent fully expanded leaf was measured

In another experiment the same Tobacco lines were grown at two application rates of N, 75 lb. per acre and 150 lb. per acre. The N applied was in the form of anhydrous ammonia rather than the ammonium nitrate used in the previous experiment. Results showed a consistent numerical advantage, though not statistically different advantage, to gdhA transformed plant lines over uidA or bar transformed plant lines in dry weight, number of leaves and width of leaves at both 175 and 150 lb. of applied nitrogen (Table 6B and Table 6C).

Combined results for both experiments showed a consistent numerical advantage to gdhA transformed plant lines over uidA and bar transformed plant lines in dry weight and number of leaves (Table 6D). However, the differences were not statistically different since the data contained a lot of variability caused by weed pressure on the peripheral plots.

TABLE 6E

Amino Acid Analysis

150# per Acre

Amino acid analyses of seed samples collected from field grown gdhA transformed tobacco lines

2A1, 913, 842, and 9Z1 uidA transformed tobacco line 7B1 and bar transformed tobacco line BAR.

These numbers represent the proportion of the total hydrolyzable amino acids.

2A1

#913

#842

9Z1

7B1

BAR

P value

LSD

.05

ALANINE

0.0525

0.0519

0.0513

0.0518

0.0504

0.0501

0.0110

0.0013

ARGININE

0.1095

0.1116

0.1146

0.1133

0.1157

0.1153

0.0046

0.0033

ASPARTIC ACID

0.1225

0.1210

0.1170

0.1174

0.1153

0.1165

0.0027

0.0036

GLUTAMIC ACID

0.2036

0.2058

0.2065

0.2071

0.2105

0.2116

0.0004

0.0033

GLYCINE

0.0544

0.0533

0.0541

0.0537

0.0537

0.0532

0.0128

0.0007

HISTIDINE

0.0227

0.0227

0.0226

0.0227

0.0222

0.0227

0.4617

0.0006

ISOLEUCINE

0.0425

0.0434

0.0414

0.0441

0.0422

0.0442

0.1552

0.0025

LEUCINE

0.0725

0.0731

0.0730

0.0733

0.0732

0.0731

0.4910

0.0010

LYSINE

0.0322

0.0331

0.0309

0.0326

0.0310

0.0320

0.0006

0.0010

METHIONINE

0.0069

0.0071

0.0096

0.0092

0.0084

0.0067

0.1719

0.0029

PHENYLALANINE

0.0504

0.0508

0.0500

0.0515

0.0506

0.0508

0.0035

0.0063

PROLINE

0.0521

0.0483

0.0502

0.0486

0.0504

0.0488

0.0423

0.0026

SERINE

0.0490

0.0487

0.0498

0.0472

0.0496

0.0407

0.3473

0.0095

THREONINE

0.0456

0.0451

0.0453

0.0442

0.0445

0.0440

0.0106

0.0010

TYROSINE

0.0317

0.0304

0.0332

0.0289

0.0309

0.0286

0.0331

0.0030

VALINE

0.0521

0.0535

0.0505

0.0544

0.0511

0.0547

0.0668

0.0034

TABLE 6F

Amino Acid Analysis

75# per Acre

Amino acid analyses of seed samples collected from field grown gdhA transformed tobacco lines

2A1, 913, 842, and 9Z1, uidA transformed tobacco line 7B1 and bar transformed tobacco line BAR.

These numbers represent the proportion of the total hydrolysable amino acids.

2A1

#913

#842

9Z1

7B1

BAR

P value

LSD

.05

ALANINE

0.0526

0.0521

0.0520

0.0518

0.0501

0.0501

0.0326

0.0013

ARGININE

0.1110

0.1160

0.1170

0.1159

0.1186

0.1003

0.5925

0.0232

ASPARTIC ACID

0.1168

0.1117

0.1111

0.1112

0.1111

0.1110

0.0032

0.0032

GLUTAMIC ACID

0.2016

0.2039

0.2037

0.2070

0.2076

0.2104

0.0001

0.0031

GLYCINE

0.0544

0.0550

0.0549

0.0542

0.0545

0.0538

0.0391

0.0079

HISTIDINE

0.0237

0.0228

0.0228

0.0230

0.0230

0.0230

0.4914

0.0010

ISOLEUCINE

0.0430

0.0407

0.0427

0.0437

0.0427

0.0447

0.2471

0.0031

LEUCINE

0.0731

0.0733

0.0745

0.0744

0.0737

0.0741

0.0233

0.0010

LYSINE

0.0348

0.0312

0.0311

0.0328

0.0305

0.0320

0.0062

0.0022

METHIONINE

0.0090

0.0104

0.0091

0.0079

0.0083

0.0069

0.1216

0.0025

PHENYLALANINE

0.0500

0.0511

0.0521

0.0520

0.0511

0.0513

0.1045

0.0014

PROLINE

0.0520

0.0508

0.0487

0.0480

0.0500

0.0469

0.0010

0.0022

SERINE

0.0494

0.0506

0.0501

0.0490

0.0496

0.0482

0.3649

0.0023

THREONINE

0.0454

0.0456

0.0455

0.0448

0.0452

0.0443

0.1248

0.0011

TYROSINE

0.0315

0.0346

0.0340

0.0306

0.0324

0.0294

0.0973

0.0040

VALINE

0.0518

0.0501

0.0518

0.0537

0.0520

0.0552

0.1631

0.0039

TABLE 6G

Amino Acid Analysis

150# per Acre

Amino acid analyses of seed samples collected from field grown gdhA

transformed tobacco lines 2A1, 913, 842 and 9Z1, uidA transformed

tobacco line 7B1 and bar transformed tobacco line BAR. These numbers

represent the proportion of the total hydrolyzable amino acids.

GDH+

GDH−

P value

LSD

.05

ALANINE

0.0518

0.0503

0.0003

0.0007775

ARGININE

0.1123

0.1155

0.0081

0.0022710

ASPARTIC ACID

0.1194

0.1159

0.0116

0.0026200

GLUTAMIC ACID

0.2057

0.2111

0.0001

0.0021230

GLYCINE

0.0539

0.0534

0.0553

0.0004969

HISTIDINE

0.0227

0.0225

0.2521

0.0036150

ISOLEUCINE

0.0428

0.0433

0.5632

0.0016700

LEUCINE

0.0730

0.0731

0.5401

0.0005836

LYSINE

0.0322

0.0315

0.1261

0.0008533

METHIONINE

0.0083

0.0077

0.5448

0.0018960

PHENYLALANINE

0.0507

0.0577

0.9641

0.0005084

PROLINE

0.0499

0.0495

0.6996

0.0018320

SERINE

0.0487

0.0477

0.1771

0.0057800

THREONINE

0.0450

0.0443

0.0254

0.0006688

TYROSINE

0.0310

0.0296

0.1691

0.0021120

VALINE

0.0526

0.0531

0.6792

0.0023360

TABLE 6H

Amino Acid Analysis

75# per Acre

Amino acid analyses of seed samples collected from field grown gdhA

transformed tobacco lines 2A1, 913, 842 and 9Z1, uidA transformed

tobacco line 7B1 and bar transformed tobacco line BAR. These numbers

represent the proportion of the total hydrolyzable amino acids.

GDH+

GDH−

P value

LSD

.05

ALANINE

0.0522

0.0507

0.0009

0.0007800

ARGININE

0.1149

0.1086

0.3601

0.0138600

ASPARTIC ACID

0.1126

0.1108

0.1416

0.0024850

GLUTAMIC ACID

0.2041

0.2091

0.0001

0.0023290

GLYCINE

0.0546

0.0541

0.0663

0.0005187

HISTIDINE

0.0231

0.0230

0.7629

0.0006349

ISOLEUCINE

0.0426

0.0438

0.2308

0.0019700

LEUCINE

0.0739

0.0739

0.8276

0.0071220

LYSINE

0.0325

0.0313

0.1349

0.0016580

METHIONINE

0.0090

0.0075

0.0523

0.0015320

PHENYLALANINE

0.0511

0.0512

0.7059

0.0009534

PROLINE

0.0498

0.0481

0.0718

0.0018760

SERINE

0.0498

0.0488

0.1720

0.0014260

THREONINE

0.0453

0.0447

0.0652

0.0006861

TYROSINE

0.0326

0.0308

0.1647

0.0026340

VALINE

0.0519

0.0537

0.1463

0.0024610

TABLE 6I

Amino Acid Analysis

Corn

Amino acid analyses of grain samples collected from field grown

transformed corn inbred lines H99 (untransformed), LL3-68 and

These number represent the proportion of total hydrolyzable amino acids.

H99

LL3-68

LL8-67

GDH−

GDH+

GDH+

Aspartic acid

0.0614

0.0635

0.065300

Threonine

0.0371

0.0381

0.038400

Serine

0.0527

0.0531

0.053600

Glutamic Acid

0.2158

0.2092

0.217800

Proline

0.1061

0.0980

0.108800

Glycine

0.0318

0.0353

0.032800

Alanine

0.0815

0.0802

0.084600

Valine

0.0459

0.0471

0.050100

Methionine

0.0152

0.0145

0.016500

Isoleucine

0.0347

0.0349

0.036100

Leucine

0.1491

0.1439

0.152000

Tyrosine

0.0266

0.0305

0.028300

Phenylalanine

0.0552

0.0549

0.055600

Histidine

0.0277

0.0298

0.029500

Lysine

0.0218

0.0253

0.023600

Arginine

0.036700

0.041200

0.036300

Amino acid analysis of seed collected from the plants grown in the later experiment showed that the seed content of several agriculturally important amino acids could be increased by the presence of the gdhA gene (Table 6 E, F, G and H). Alanine, lysine and threonine contents were significantly increased by gdhA. Glutamate, arginine and phenylalanine were significantly decreased. Higher lysine and threonine content could increase the value of seed and grain crops used for animal feed. Lysine is a rate limiting amino acid in the diet of swine. Thus the present invention when placed in a swine diet will decrease the need to supplement the swine diet with added lysine. Thus a new use for the present invention is incorporation into corn grain and soybean grain to supply increased amounts of lysine to swine fed the diet by using grain of the present invention. Additionally, this gene in combination with other genes that overexpress the desired amino acid is contemplated in this invention.

Numerical differences in content were noted for most amino acids. gdhA increased alanine, aspartic acid, glycine, lysine, methionine, proline, serine, threonine and tyrosine; these increased contents increase the value of seed and grain crops used for animal feed. Methionine, is a rate limiting amino acid in the diet of poultry. Thus the present invention when placed in a swine diet will decrease the need to supplement the poultry diet with added methionine.

Comparison of amino acid contents of transgenic corn (Table 6I) showed that gdhA increased the content of apartic acid, threonine, serine, glycine, valine, methionine, tyrosine, histidine, lysine and arginine. These increased contents could increase the value of seed and grain crops used for animal feed. Comparison with the effects of gdhA expression in tobacco on seed amino acid content suggests that changes will be dependent on the plant species and genetic background in which gdhA has an effect.

EXAMPLE VI

Construction of Plasmids to Transfer

E. coli

gdhA to

Zea mays.

The pBI121::GDH plasmid (shown in

FIG. 4

) was not particularly suitable for use in

Zea mays

. Thus, the plasmid pUBGPI (shown in

FIG. 5

) which is a vector suitable for transformation of

Zea mays

and foreign gene expression was employed.

The modified

E. coli

gdhA gene (shown in

FIG. 6A

as SEQ ID NO:12) was readily transferred to pUBGP1 to replace the GUS (uidA) gene by restriction digestion, gel purification of appropriate fragments and ligation as follows. Digestion of pBI121::GDH (shown in

FIG. 4

) with XbaI and EcoRI allowed recovery of gdhA::nosT as a 1.6 kbp fragment. Ligation with EcoRI XbaI digested pUC18 produced the plasmid pUCGDH1 which was amplified in

E. coli

DH5. Digestion of pUCGDH1 with PstI and EcoRII allowed recovery of the gdhA::nosT as a 1.6 kbp fragment. This mutagenized gdhA gene with the added linker restriction sites is shown in

FIG. 7A

(SEQ ID NO:14). Digestion of pUBGP1 with NcoI and SphI allowed recovery of the vector minus GUS::nosT as the 1.0 and 5.6 kbp fragments. Digestion of the 1.0 kbp fragment with PstI removed one NcoI site (and an inappropriate ATG codon). The 1.0 and 5.6 kbp pUBGPI fragments were ligated with the 1.6 kbp fragment from pBI121::GDH1 and an EcoRI/SphI adapter (shown in

FIG. 8

as SEQ ID NOS:15-16).

The 3′ EcoRI SphI adapter is between nosT and the plasmid for corn transformation. This gives pUBGDH1 (shown in

FIG. 9

) which was amplified in

E. coli

DH5.

The plasmid pUBGDH1 (shown in

FIG. 9

) was purified as DNA from

E. coli

, and 1 μg were used for transformation of

Zea mays

inbred line H99 by biolistics.

EXAMPLE VII

Construction of Plasmid to Target the

E. coli

gdbA to Chloroplasts in Corn.

Because the pBI121::GDH plasmid was not suitable for

Zea mays

transformation or gene expression, another plasmid vector was used to achieve gdhA gene transfer and expression. The 1.8 kbp SmaI to EcoRI fragment of pBI121::SSU::GDH1 was isolated and ligated with an EcoRI/SmaI adapter and Smal digested pUC18. This produced the plasmid pUCSSUGDH1 which was amplified in

E. coli

DH5. Digestion of pUCSSUGDH1 with SmaI allowed recovery of the SSU::gdhA::nosT as a 1.8 kbp fragment (FIG.

7

B). Digestion of pUBGP1 with NcoI and SphI allowed recovery of the vector minus GUS::nosT as the 1.0 and 5.6 kbp fragments. Digestion of the 1.0 kbp fragment with PstI removed the NcoI site (and an inappropriate ATG codon). The 1.0 and 5.6 kbp pUBGPI fragments were ligated with the 1.8 kbp fragment from pUCSSUGDH1 and an PstI/SmaI adapter to give pUBSSUGDH1 (

FIG. 10

) which was amplified in

E. coli

DH5.

The plasmid pUBSSUGDH1 was purified as DNA from

E. coli

, and 1 μg can be used for transformation of the

Zea mays

inbred line by any method.

EXAMPLE VIII

Method of Biochemical Analyses of Herbicide Resistance

Biochemical Analyses of Transformed Plants of the Above Examples.

Herbicide Resistance

Phosphinothricin (PPT) resistance was tested by initiating gdhA transformed leaf discs from greenhouse grown R

o

plants on MSO medium containing 1 mg/l BA, 0.1 mg/l NAA, 3% w/v sucrose and 7 g/l agar was supplemented with the herbicide IGNITE glufosinate at 0, 0.1, 1.0 or 10.0 mg/l active ingredient (a.i.) (5 replications of 1 cm

2

discs in individual culture tubes per concentration). Four weeks after initiation, cultures were photographed and the volume of leaf discs was measured.

R

1

Seed from gdbA transformed R

0

plants were also tested for herbicide resistance by germination and growth on MSO medium containing 3% w/v Sucrose and 7 g/l Agar supplemented with 0, 3, 9, 27 or 81 mg/l a.i. IGNITE glufosinate (30 seeds per plate with 3 replications per concentration) or 0, 1, 3, 10, 30 mg/l as noted in the text. Cultures were maintained at 25° C. with 16 hours of light. Four weeks after germination, cultures were photographed.

The gdhA transformed R

0

plants were also tested for herbicide resistance by painting leaves with 0, 3, 9, 27 or 81 mg/ml a.i. IGNITE glufosinate. Plants were maintained in the greenhouse. Four days after application chlorosis was scored.

Ammonium Toxicity Resistance

Resistance to ammonium toxicity in the absence of nitrate was measured by germinating transformed tobacco seed on agar solidified MSO medium excluding nitrogen. The medium was supplemented with 10, 30, 50, 70 or 100 mM ammonium chloride and seedlings were grown either with or without 30 mg/l sucrose. Ten to 15 seed were initiated per plate with 4 replications per concentration. Fresh and dry weights of 10 seedlings per plate were measured after 6 weeks on these media. Statistical analyses of these data were performed using SAS (SAS Institute Inc. Cary, N.C.).

The gohA transformed R

0

plants were also tested for ammonium resistance by painting leaves with 100, 300, 500, 700 or 1000 mM ammonium chloride. Plants were maintained in the greenhouse. Four days after application chlorosis was scored.

TABLE 7

Mean growth traits of adult transgenic corn FH24 inbred segregates

in the greenhouse at Carbondale were significantly different.

Liberty

NADPH-GDH

Resistance

Ear Leaf

Plant

Ear Leaf

Plant

Activity

%

Area

Height

N Content

Line

(nM/mg/min)

Applied

a

(cm

3

)

(cm)

(%)

LL9-37+

b

400

2

646

147

3.75

LL9-37−

0

0

330

113

3.72

Prob.

c

0.0001

0.0001

0.03

0.1

0.05

a

Liberty was painted onto a 1 cm

3

area of a mature leaf at 1%, 2%, 3% and 4% (v/v). Chlorosis after 4 weeks indicated susceptibility. The highest concentration to which plants were resistant is reported.

b

LL9-37+ = GDH positive segregants from a gdhA transformant of corn.

LL9-37− = GDH negative segregants from a gdhA transformant of corn.

b

Prob. = probability that the LL9-37+ and LL-37− segregates were significantly different.

This data show that in adult plants the height and ear leaf area of the gdhA transformant corn are significantly different than the isogeneic segregates lacking gdhA. However, nitrogen content is similar. The gdhA is efficient in increasing plant growth and yield. This test indicates that the present invention is tolerant at certain concentrations to glufosinate herbicides such as LIBERTY glufosinate. However, this test also indicates that the nitrogen content is similar. The gdhA is efficient in increasing plant growth and yield.

TABLE 8

Nitrogen runoff rate in tobacco and corn expressing gdhA.

Ammonium

Nitrite

Nitrate

NADPH-GDH

Concen-

Concen-

Concen-

Plant

Activity

tration

tration

tration

Line

(nM/mg/min)

(mM)

(mM)

(mM)

Tobacco

BAR

0

0.031

0.224

0.374

2A

2046

0.022

0.189

0.298

Corn

LL1-128−

0

0.045

0.123

0.277

LL1-128+

800

0.030

0.117

0.226

The corn plants used were isogeneic hybrid segregates derived from a cross from LL1-128 with A632. The presence or absence of gdhA was determined by leaf painting with 1% (w/v) LIBERTY glufosinate and spectrophotometric assay of GDH activity. Values presented are the means from eight plants. In each case, the gdhA transformants have increased the glutamate concentration in the plant roots significantly. The glutamine concentration also appears raised though not significantly.

EXAMPLE IX

I. Uptake Experiments

Seeds from gdhA transformed plants and seeds from uidA transformed plants were germinated on MSO medium without nitrogen. The medium was supplemented with 4% w/v sucrose. Two weeks after germination, the nitrogen starved seedlings were used to test whether the gdhA transformed seedlings were capable of absorbing radiolabelled methylammonium at a greater rate than the uidA transformed control plants. Fifteen seedlings were floated in the treatment solution (0.2 mM CaCl

2

, 0.2 mM Mes pH 6.0, and 200 μM KCl) for 10 minutes. Radiolabelled 14C-methylammonium was then added to the treatment solution at a concentration of 1 mM. After 12, 24, 36, 48 or 60 minutes the labeled solution was aspirated and replaced with nonlabeled solution. The wash solution was aspirated after 2 minutes and the seedlings were transferred to scintillation vials. The seedlings were ground in 1 ml of water for 2 min. with a polytron (Tekmar Cinn. Ohio) to break open the cells. 2 mls of scintillation fluid was added per vial. The radioactivity absorbed by each sample was counted using an LS6000 scintillation counter (Beckman, Calif.) with an open window.

As indicated above in the previous example, the biochemical analysis of methylammonium uptake was tested. The transformed tobacco developed under the first couple of examples were employed in the uptake study. The results are shown in FIG.

11

. The uptake of both the uidA and gdhA lines without 1 mM NH

4

was greatly enhanced in the time frame given.

II. Herbicide Resistance

A surprising aspect of the present gene in plant transformants is its tolerance to the herbicide phosphinothricin. The addition of the gdhA gene to either the PAT gene or the Bar gene apparently provides the plant with added resistance as shown by the plants' ability to continue to flourish and grow in increasing concentrations of herbicide. There are a number of commercially available herbicides that fit within the class of phosphinothricin herbicides.

The tobacco transformants of gdhA and uidA do not carry either the bar nor the PAT gene. A control used for comparison was a tobacco transformant containing the Bar gene. In contrast, the corn transformants all contain the PAT gene as the selectable marker. Therefore, the corn transformants show that the combination of phosphinothricin resistant gene(s) such as PAT in combination with the gdhA gene provides plants with increased resistance to chlorosis.

EXAMPLE X

GDH Activity of gdhA Transformants and Controls.

The tobacco transformants including the Bar transformant were developed either in examples provided earlier or by similar methods. The biochemical analysis was performed as indicated above. The results are as follows:

TABLE 9

Characteristics of the tobacco transgenic plant lines

recovered.

Explants

Strain/Gene

Inoculated

gdhA

a

PPT

b

EHA101/gdhA

30

12

10

LBA4404/gdhA

30

2

1

LBA4404/gdhA

15

0

0

EHA101/uidA

15

0

0

LBA4404/bar

15

0

4

a

= positive bands after electrophoresis of crude extract on 5% polyacrylamide gel followed by NADP-dependent tetrazolium staining of GDH isozymes.

b

= Seedlings resistant to 3 μg a.i./ml PPT.

Clearly, both the LBA4404/bar and EHA100/gdhA lines as seedlings were resistant to 3 μg a.i./ml PPT. Thus, the tobacco plants can be sprayed in a field with weeds with the PPT herbicide and at least at the indicated levels of PPT will not have chlorosis evidenced.

EXAMPLE XI

Volume of tobacco callus formed in present of various levels of PPT. The transformants of the earlier examples were tested in various herbicide concentrations.

TABLE 10

Mean volume of tobacco callus

a

with various concentrations of the herbicide (PPT).

Herbicide

Transformed Lines

conc.

2A (gdhA)

8

2

(gdhA)

9

1

(gdhA)

7B (uidA)

mg. a.i./l

(cm

3

)

n

b

(cm

3

)

n

(cm

3

)

n

(cm

3

)

n

Significance

c

0.0

20929.4

d

5

17275.0

5

20763.2

5

16056.9

3

NS

0.1

12873.2

5

11489.0

3

14949.5

4

2515.9

2

**

1.0

3828.7

4

6478.1

5

9634.0

5

0.0

4

**

10.0

0.0

5

0.0

5

0.0

5

0.0

4

NS

a

Greenhouse grown leaf tissue from gdhA or uidA R

0

transformed plants were initiated on MS medium in culture tubes and incubated in the light at 25° C. for 4 weeks before volume was calculated.

b

n = number of explants

c

** = significant at the 1% level, NS = nonsignificant

d

volume was calculated using the formula 3.14 r

2

h

The evidence clearly indicates that the volume of callus of uidA tobacco callus in PPT is significantly less then callus of the gdhA tobacco.

TABLE 11

Dry weight of R

1

leaf derived callus

a

with various concentrations of the herbicide (PPT).

Callus GDH

Dry weight (mg) at

activity

herbicide concentration

Transformed

(nmol/

(mg a.i./l)

Lines

mg

a

/min)

0

1

3

BAR

0

217

(8)

b

191

(7)

185

(6)

9

1

1640

267

(8)

215

(10)

48

(9)

9X

1610

227

(10)

167

(9)

30

(10)

2A

1510

269

(9)

159

(10)

23

(10)

9

2

N

570

269

(9)

168

(10)

48

(10)

9

5

W

330

239

(9)

124

(9)

13

(9)

9

4

R

290

256

(9)

94

(5)

11

(10)

7B

0

215

(10)

33

(8)

4

(9)

Significance

LSD.05

56

34

12

LSD.01

83

51

18

Standard

526

61

48

Deviation

a

Greenhouse grown leaf tissue from gdhA or uidA R

1

transformed plants were initiated on MS medium in culture tubes and incubated in the light at 25° C. for 4 weeks before GDH assays. Specific activity per mg of soluble protein with 10 mM ammonium chloride.

b

number of explants is shown in parentheses

Volume of tobacco callus formed in the presence of various concentrations of the herbicide LIBERTY glufosinate clearly indicate that callus volume is dependent on the level of expression of gdhA as detected by GDH enzyme assays.

EXAMPLE XII

Volume of Corn Callus in Present of PPT

The volume of corn callus by volume was calculated in light of different transformant lines. Unlike the previous example, there is no control line that does not carry a PAT gene. Both the gdhA and the uidA transformants contain PAT which has resistance to PPT.

EXAMPLE XIII

RO Plants Herbicide Resistance

The results of herbicide resistance in R

0

corn and tobacco transformants and the gdhA activity as measured by NADPH-GDH was compared. The following results were gathered.

TABLE 12

Herbicide resistance concentration dependence

and GDH activity in R0 plants expressing gdhA.

NADPH-GDH

PPT concentration

Plant

Activity

(mg a.i/ml)

Line

(nM/mg/min)

0

1

2

3

4

a, Tobacco

UID

0

+

−

−

nd

nd

2A

2046

+

+

+

nd

nd

82

2060

+

+

+

nd

nd

91

1840

+

+

+

nd

nd

9Z1

1760

+

+

+

nd

nd

BAR

0

+

+

+

nd

nd

b, Corn (all contain the pat gene)

LL3-775#131

1310

+

+

+

+

+

LL2-63#12

500

+

+

+

+

−

LL2-63#15

300

+

+

+

−

−

LL2-63#9

150

+

+/−

−

−

−

LL2-63#6

0

+

−

−

−

−

nd not determined

+ resistance to chlorosis

− chlorotic 2-3 weeks after treatment

The above experiment clearly indicates the herbicide tolerance in the plants of the present invention is increased over the control plants. The results show that transformants without the gdhA gene provide no protection against the herbicide, The transformant line 9Z1 evidences the least amount of NADPH-GDH activity and it still gives resistance to 2% LIBERTY glufosinate solution.

Activity levels of NADPH-GDH of 1000 and over provided PPT resistance in tobacco. In corn, which has added PPT resistance, the controls were not resistant to 1% liberty leaf paint. However, as activity levels of GDH increased so did resistance to LIBERTY glufosinate. The combination of the pat gene and gdhA gene in corn shows even a 4% solution of LIBERTY glufosinate can be resisted (line LL3-775#131).

EXAMPLE XIV

Progeny of corn plants containing gdhA gene and either the Bar gene or the PAT gene which are bred and developed from the seeds of the R

0

plants of the examples above can be planted in a field. This field could then be sprayed for weeds with a phosphinothricin herbicide such as IGNITE glufosinate. This is a method of increasing plant growth. This herbicide spraying would eliminate most of the undesirable vegetation and the plants containing the gdhA gene would survive and increase growth. Alternatively, the corn plants can be transformed with the gdhA gene only and not include the selectable marker of either Bar or PAT. This transformant would be expected to survive the spraying and also show increased growth though it may be slightly less tolerant.

R

1

Tobacco Seedling Growth After Four Weeks on LIBERTY Glufosinate (PPT).

The experiment had a bar only line, a gdhA (line 2A) and uidA (line 7A) transformed R

1

seedlings germinated on agar solidified MS medium supplemented with 3 mg/l a.i. of the herbicide LIBERTY glufosinate (PPT). The bar only line filled about 90% of the petri dish with seedlings, the gdhA (line 2A) line filled about 40% of the petri dish with seedlings, and uidA (line 7A) line filled about 10% of the petri dish with seedlings.

Eight Week Old R

1

Tobacco Plants

Eight week old R

1

tobacco plants one week after they were sprayed to runoff with a 1% solution of the herbicide LIBERTY glufosinate were visually examined. line 7B (uidA) 0 nmol/mg/min GDH activity had obvious leaf death and had turned a light green color. Line 9

1

(gdhA) 1840 nmol/mg/min GDH activity had some leaf spotting but had not turned a light green; line 2A (gdhA) 2040 nmol/mg/min GDH activity; line 8

2

(gdhA) 2060 nmol/min/mg GDH activity both appeared healthier then Lines 9

1

and 9Z

1

but still had some though less then 9

1

and 9Z

1

leaf spotting; line 9Z

1

(gdhA) 1760 nmol/min/mg GDH activity had some leaf spotting but had not turned a light green; line BAR (bar) 0 nmol/mg/min GDH activity was significantly darker green and showed little to no leaf spotting.

Eight Week Old R

1

Inbred Corn Plants

Eight week old inbred corn plants were visually examined one week after they were leaf painted with a 1%, 2%, 3% or 4% (v/v) solution of the herbicide LIBERTY glufosinate. Line LL3-755#131 (gdhA) having 1310 nmol/mg/min GDH activity showed no visible effects to 1-3% and only a barely discernible light browning in a small area at 4%. Line LL2-63#12 (gdhA) 500 nmol/mg/min GDH activity showed no apparent effects at 1%, slight browning (significantly more then line LL3-

755

#

131

at 4%) at 2% and about 60% browning at 3% and 100% browning at 4%. Line LL2-63#6 (no transgene sergeant otherwise isogeneic to LL2-63#12) 0 nmol/mg/min GDH activity showed 100% browning in the painted area at land 2% and extended browning outside of the area at 3% and 4%. These plant correspond to those described in Table 13.

The gdhA gene can be transformed into crop plants that would not be expected to be effected by the herbicide PPT. This would allow better growth of these plants in fields that are sprayed or in those that are not sprayed.

EXAMPLE XV

Improved crop nitrogen assimilation can reduce environmental contamination by nitrates. Specialty corn hybrids for planting in watershed areas or for biofuel feedstocks will be developed.

Nitrogen Runoff Determinations

Plants were fertilized with 1 liter of 10 mM ammonium nitrate and subsequently not watered or fertilized. After 48 hours, the root system was flushed with 10 liters of water and the runoff water from each pot collected. The ammonia concentration in each run-off water sample was determined by Nesslerization. Briefly, 1 ml. of sample was mixed with 1 ml. of 0.2% gum acacia solution, 1 ml. of Nesslers reagent, 7 ml. of water. After 20 minutes, the absorbance was determined at 420 nm. The nitrite concentration was determined by mixing 2 ml. of sample. 5 ml. of sulphanilic acid solution and 5 ml. of alpha-napathyl amine solution. After 30-60 minutes, the absorbance was determined at 540 nm. The nitrate concentration was determined by the 4-methylumbelliferone method. Briefly, 0.5 ml. of sample was mixed with 50 μl of 1 M sulfamic acid and heated to 100 C for 5 minutes. On ice 10 ml. of 4.4 M ammonia. After 20 minutes at room temperature, the absorbance was determined at 540 nm.

TABLE 13

Nitrogen runoff rate in tobacco and corn expressing gdhA.

Ammonium

Nitrate

Nitrate

NADPH-GDH

Concen-

Concen-

Concen-

Plant

Activity

tration

tration

tration

Line

(nM/mg/min)

(mM)

(mM)

(mM)

a, Tobacco

BAR

0

0.3

0.3

0.4

2A

2046

0.2

0.1

0.2

b, Corn

DL1

0

0.2

0.3

0.5

LL1

800

0.1

0.1

0.2

These results show that the gdhA gene can be used to decrease the nitrogen content of runoff-water. The increased assimilation by plant roots results in less nitrogen to be available for leaching.

Significance

Biofuels/Watershed Premium

Unassimilated nitrogen is converted to nitrate and much is leached from the soil and into groundwater. The EPA is already considering setting limits on nitrogen use in watershed areas. Agricultural inputs contribute to nitrogen contamination in Illinois drinking water, particularly in the North Central region. More than 18 community water supplies and 25% of the 360,000 private wells contain concentrations of nitrogen above the EPA limits. Improving corn nitrogen assimilation with foreign transgenes may reduce nitrogen loss by increasing assimilation. Attempts to develop such corn might be used to delay restrictive legislation and increase support for corn derived biofuels. Approximately 20% of Illinois farmland is in watershed areas. An increase of 10% in the corn derived ethanol as oxygenate addition to gasoline would double the demand for corn and would lead to higher corn prices.

Health Benefits

The association between dietary nitrates and several cancers is weak but positive (Moller et. al. 1990). Groundwater consumption can be a significant source of dietary nitrates in Illinois (Lee and Neilson 1987). Reducing groundwater contamination by nitrates may have a small beneficial effect on the rate of cancers. Infants 9-6 years old are at particular risk from dietary nitrates because nitrate reacts strongly with their blood hemoglobin causing methemoglobinemia, a condition similar to carbon monoxide poisoning in adults (Marschner, 1995). Bottled water is periodically recommended for infants in 18 Illinois communities with high nitrogen in their water supplies. Dietary nitrates are associated with higher abortion rates (Prins, 1983).

Environmental Premium

A health food or environmental premium on the market price of improved corn might be developed by marketing strategies. This might also lead to increased utilization. If a 1 cent per bushel premium for “low nitrogen impact” corn developed and Illinois farmers grew 1.74 billion bushels then profits would increase $17.4 million in Illinois.

Reduced Producer Losses

Assuming a 10% nitrogen loss, 175 lb./acre use, 10 cents/lb. cost, and 13 million acres planted then income losses are: 0.1×175×10×13,000,000=$23 million or $1.75 per acre. Although annual producer losses may approach $23 million per year in Illinois this is likely to vary depending on weather, soil types and cultural practices. The technology proposed might reduce producer expenses some part of that $23 million per year in Illinois.

EXAMPLE XVI

Altered Seed Composition

Using the R

0

plants produced by the previous examples, the plants can be further modified to include genes that alter seed composition. A number of these types of genes are known in the art. These genes make altered hybrids. Altered seed composition leads to several specialty corn hybrids and products. High protein corn could be produced by increasing nitrogen assimilation. High sucrose corn or increased starch accumulation could be produced by simultaneous manipulation of carbon and nitrogen metabolism. The gdhA gene used in association with genes that alter starch content or chemical form or sugar content or form to promote alterations in plant composition.

TABLE 14

The effect of gdhA on plant seed carbohydrate composition.

Tobacco grown with 75 lb. per acre anhydrous N.

GDH+

GDH−

Mean

Mean

Starch 1

0.72100

0.32250

0

0

Starch 2

0.03325

0.03250

(o/n)

0

0

Red

3.56375

3.66750

Sugar

0

0

Pentose

0.45825

0.18300

0

0

Hexose

0.57500

0.84700

0

0

Sucrose

1.03325

1.03000

0

0

This experiment shows that starch content was much higher in the GDH+ transgenic plants than those lacking gdhA. Therefore, gdhA can be used to increase starch content of crops such as corn, potato and tomato to improve their food processing characteristics and the % of extractable starch. No additional starch could be extracted by the overnight treatment and the GDH+ and GDH− lines did not differ. The sucrose and total reducing sugar contents are not affected by the increase in starch content caused by gdhA. However, there are more pentose sugars and less hexose sugars in the gdhA transgenic plants. These results show that gdhA can be used to alter the type of sugar of crops such as corn, potato, tomato, sugar beet and sugar cane to improve their food processing characteristics.

TABLE 15

The effect of gdhA on plant seed carbohydrate composition.

Tobacco grown with 150 lb. per acre anhydrous N.

GDH+

GDH−

Mean

Mean

Starch 1

0.84675

0.60650

0

0

Starch 2

0.03275

0.05150

(o/n)

0

0

Red

3.64300

3.53060

Sugar

0

0

Pentose

0.58300

0.14125

0

0

Hexose

0.73650

0.47000

0

0

Sucrose

1.31950

0.61125

0

0

This experiment shows that at higher nitrogen input (150 lb. per acre) starch content was much higher in the GDH+ transgenic plants than those lacking gdhA. Therefore, gdhA can be used to increase starch content of crops such as corn, potato and tomato to improve their food processing characteristics and the % of extractable starch. Some additional starch could be extracted by the overnight treatment and the GDH+ and GDH− lines did not differ significantly. The sucrose and total reducing sugar contents are not affected by the increase in starch content caused by gdhA. However, there are more pentose sugars, hexose sugars and sucrose in the gdhA transgenic plants. These results show that gdhA can be used to alter the amount of sugar at high N input rates. Therefore gdhA can be use to increase the value of crops such as corn, potato, tomato, sugar beet and sugar cane and improve their food processing characteristics.

The use of gdhA in association with other transgenes, mutants or cultivars that affect starch and sucrose content is envisioned. Cotransformation or crossing of transgenic plants to contain gdhA and genes encoding ADPglucose pyrophosphorylase (glgC), cytoplasmic and chloroplastic fructose-1-6-bisphosphatase, sucrose phoshate synthase. triose phosphate tanslocator, phosphglucose isomerase, Fructose-6-phosphate kinase, UDP glucose pyrophosphorylase, invertase, phosphofructoldnase, ribulose bisphosphate caiboxylase and the glucose tansports is envisioned within the scope of the present invention (Stitt and Sonnewald, 1995, Annu. Rev. Plant Physiol. Plant Mol. Biol. 46:341-368).

1659 bases

nucleic acid

single

linear

DNA (genomic)

not provided

1
TCGAAAACTG CAAAAGCACA TGACATAAAC AACATAAGCA CAATCGTATT AATATATAAG 60
GGTTTTATAT CTATGGATCA GACATATTCT CTGGAGTCAT TCCTCAACCA TGTCCAAAAG 120
CGCGACCCGA ATCAAACCGA GTTCGCGCAA GCCGTTCGTG AAGTAATGAC CACACTCTGG 180
CCTTTTCTTG AACAAAATCC AAAATATCGC CAGATGTCAT TACTGGAGCG TCTGGTTGAA 240
CCGGAGCGCG TGATCCAGTT TCGCGTGGTA TGGGTTGATG ATCGCAACCA GATACAGGTC 300
AACCGTGCAT GGCGTGTGCA GTTCAGCTCT GCCATCGGCC CGTACAAAGG CGGTATGCGC 360
TTCCATCCGT CAGTTAACCT TTCCATTCTC AAATTCCTCG GCTTTGAACA AACCTTCAAA 420
AATGCCCTGA CTACTCTGCC GATGGGCGGT GGTAAAGGCG GCAGCGATTT CGATCCGAAA 480
GGAAAAAGCG AAGGTGAAGT GATGCGTTTT TGCCAGGCGC TGATGACTGA ACTGTATCGC 540
CACCTGGGCG CGGATACCGA CGTTCCGGCA GGTGATATCG GGGTTGGTGG TCGTGAAGTC 600
GGCTTTATGG CGGGGATGAT GAAAAAGCTC TCCAACAATA CCGCCTGCGT CTTCACCGGT 660
AAGGGCCTTT CATTTGGCGG CAGTCTTATT CGCCCGGAAG CTACCGGCTA CGGTCTGGTT 720
TATTTCACAG AAGCAATGCT AAAACGCCAC GGTATGGGTT TTGAAGGGAT GCGCGTTTCC 780
GTTTCTGGCT CCGGCAACGT CGCCCAGTAC GCTATCGAAA AAGCGATGGA ATTTGGTGCT 840
CGTGTGATCA CTGCGTCAGA CTCCAGCGGC ACTGTAGTTG ATGAAAGCGG ATTCACGAAA 900
GAGAAACTGG CACGTCTTAT CGAAATCAAA GCCAGCCGCG ATGGTCGAGT GGCAGATTAC 960
GCCAAAGAAT TTGGTCTGGT CTATCTCGAA GGCCAACAGC CGTGGTCTCT ACCGGTTGAT 1020
ATCGCCCTGC CTTGCGCCAC CCAGAATGAA CTGGATGTTG ACGCCGCGCA TCAGCTTATC 1080
GCTAATGGCG TTAAAGCCGT CGCCGAAGGG GCAAATATGC CGACCACCAT CGAAGCGACT 1140
GAACTGTTCC AGCAGGCAGG CGTACTATTT GCACCGGGTA AAGCGGCTAA TGCTGGTGGC 1200
GTCGCTACAT CGGGCCTGGA AATGGCACAA AACGCTGCGC GCCTGGGCTG GAAAGCCGAG 1260
AAAGTTGACG CACGTTTGCA TCACATCATG CTGGATATCC ACCATGCCTG TGTTGACCAT 1320
GGTGGTGAAG GTGAGCAAAC CAACTACGTG CAGGGCGCGA ACATTGCCGG TTTTGTGAAG 1380
GTTGCCGATG CGATGCTGGC GCAGGGTGTG ATTTAAGTTG TAAATGCCTG ATGGCGCTAC 1440
GCTTATCAGG CCTACAAATG GGCACAATTC ATTGCAGTTA CGCTCTAATG TAGGCCGGGC 1500
AAGCGCAGCG CCCCCGGCAA AATTTCAGGC GTTTATGAGT ATTTAACGGA TGATGCTCCC 1560
CACGGAACAT TTCTTATGGG CCAACGGCAT TTCTTACTGT AGTGCTCCCA AAACTGCTTG 1620
TCGTAACGAT AACACGCTTC AAGTTCAGCA TCCGTTAAC 1659

1659 bases

nucleic acid

single

linear

DNA (genomic)

YES

not provided

2
TCGAAAACTG CAAAAGCACA TGACATAAAC AACATAAGCA CAATCGTATT AATATATAAG 60
GGTTCTAGAA CAATGGATCA GACATATTCT CTGGAGTCAT TCCTCAACCA TGTCCAAAAG 120
CGCGACCCGA ATCAAACCGA GTTCGCGCAA GCCGTTCGTG AAGTAATGAC CACACTCTGG 180
CCTTTTCTTG AACAAAATCC AAAATATCGC CAGATGTCAT TACTGGAGCG TCTGGTTGAA 240
CCGGAGCGCG TGATCCAGTT TCGCGTGGTA TGGGTTGATG ATCGCAACCA GATACAGGTC 300
AACCGTGCAT GGCGTGTGCA GTTCAGCTCT GCCATCGGCC CGTACAAAGG CGGTATGCGC 360
TTCCATCCGT CAGTTAACCT TTCCATTCTC AAATTCCTCG GCTTTGAACA AACCTTCAAA 420
AATGCCCTGA CTACTCTGCC GATGGGCGGT GGTAAAGGCG GCAGCGATTT CGATCCGAAA 480
GGAAAAAGCG AAGGTGAAGT GATGCGTTTT TGCCAGGCGC TGATGACTGA ACTGTATCGC 540
CACCTGGGCG CGGATACCGA CGTTCCGGCA GGTGATATCG GGGTTGGTGG TCGTGAAGTC 600
GGCTTTATGG CGGGGATGAT GAAAAAGCTC TCCAACAATA CCGCCTGCGT CTTCACCGGT 660
AAGGGCCTTT CATTTGGCGG CAGTCTTATT CGCCCGGAAG CTACCGGCTA CGGTCTGGTT 720
TATTTCACAG AAGCAATGCT AAAACGCCAC GGTATGGGTT TTGAAGGGAT GCGCGTTTCC 780
GTTTCTGGCT CCGGCAACGT CGCCCAGTAC GCTATCGAAA AAGCGATGGA ATTTGGTGCT 840
CGTGTGATCA CTGCGTCAGA CTCCAGCGGC ACTGTAGTTG ATGAAAGCGG ATTCACGAAA 900
GAGAAACTGG CACGTCTTAT CGAAATCAAA GCCAGCCGCG ATGGTCGAGT GGCAGATTAC 960
GCCAAAGAAT TTGGTCTGGT CTATCTCGAA GGCCAACAGC CGTGGTCTCT ACCGGTTGAT 1020
ATCGCCCTGC CTTGCGCCAC CCAGAATGAA CTGGATGTTG ACGCCGCGCA TCAGCTTATC 1080
GCTAATGGCG TTAAAGCCGT CGCCGAAGGG GCAAATATGC CGACCACCAT CGAAGCGACT 1140
GAACTGTTCC AGCAGGCAGG CGTACTATTT GCACCGGGTA AAGCGGCTAA TGCTGGTGGC 1200
GTCGCTACAT CGGGCCTGGA AATGGCACAA AACGCTGCGC GCCTGGGCTG GAAAGCCGAG 1260
AAAGTTGACG CACGTTTGCA TCACATCATG CTGGATATCC ACCATGCCTG TGTTGACCAT 1320
GGTGGTGAAG GTGAGCAAAC CAACTACGTG CAGGGCGCGA ACATTGCCGG TTTTGTGAAG 1380
GTTGCCGATG CGATGCTGGC GCAGGGTGTG ATTTAAGTTG TAAATGCCTG ATGGCGCTAC 1440
GCTTATCAGG CCTACAAATG GGCACAATTC ATTGCAGTTA CGCTCTAATG TAGGCCGGGC 1500
AAGCGCAGCG CCCCCGGCAA AATTTCAGGC GTTTATGAGT ATTTAACGGA TGATGCTCCC 1560
CACGGAACAT TTCTTATGGG CCAACGGCAT TTCTTACTGT AGTGCTCCCA AAACTGCTTG 1620
TCGTAACGAT AACACGCTTC AAGTTCAGCA TCCGTTAAC 1659

37 base pairs

nucleic acid

single

linear

DNA

not provided

3
GGGTTCTAGA ACAATGGATC AGACATATTC TCTGGAG 37

35 bases

nucleic acid

single

linear

DNA

not provided

4
CATTGAGCTC TTAAATCACA CCCTGCGCCA GCATC 35

49 bases

nucleic acid

single

linear

DNA

not provided

5
GGGTTTTATA TCTATGGATC AGACATATTC TCTGGAGTCA TTCCTCAAC 49

49 bases

nucleic acid

single

linear

DNA

not provided

6
CTTGAGGAAT GACACCAGAG AATATGTCTG ATCCATAGAT ATAAAACCC 49

12 residues

amino acid

Not Relevant

protein

not provided

7
Met Asp Gln Thr Tyr Ser Leu Glu Ser Phe Leu Asn
1 5 10

38 bases

nucleic acid

single

linear

DNA

not provided

8
TGCGATGCTG GCGCAGGGTG AGATTTAAGT TGTAAATG 38

38 bases

nucleic acid

single

linear

DNA

not provided

9
CATTTACAAC TTAAATCTCA CCCTGCGCCA GCATCGCC 38

8 residues

amino acid

Not Relevant

protein

not provided

10
Ala Met Leu Ala Gln Gly Val Ile
1 5

447 residues

amino acid

Not Relevant

protein

not provided

11
Met Asp Gln Thr Tyr Ser Leu Glu Ser Phe Leu Asn His Val Gln Lys
1 5 10 15
Arg Asp Pro Asn Gln Thr Glu Phe Ala Gln Ala Val Arg Glu Val Met
20 25 30
Thr Thr Leu Trp Pro Phe Leu Glu Gln Asn Pro Lys Tyr Arg Gln Met
35 40 45
Ser Leu Leu Glu Arg Leu Val Glu Pro Glu Arg Val Ile Gln Phe Arg
50 55 60
Val Val Trp Val Asp Asp Arg Asn Gln Ile Gln Val Asn Arg Ala Trp
65 70 75 80
Arg Val Gln Phe Ser Ser Ala Ile Gly Pro Tyr Lys Gly Gly Met Arg
85 90 95
Phe His Pro Ser Val Asn Leu Ser Ile Leu Lys Phe Leu Gly Phe Glu
100 105 110
Gln Thr Phe Lys Asn Ala Leu Thr Thr Leu Pro Met Gly Gly Gly Lys
115 120 125
Gly Gly Ser Asp Phe Asp Pro Lys Gly Lys Ser Glu Gly Glu Val Met
130 135 140
Arg Phe Cys Gln Ala Leu Met Thr Glu Leu Tyr Arg His Leu Gly Ala
145 150 155 160
Asp Thr Asp Val Pro Ala Gly Asp Ile Gly Val Gly Gly Arg Glu Val
165 170 175
Gly Phe Met Ala Gly Met Met Lys Lys Leu Ser Asn Asn Thr Ala Cys
180 185 190
Val Phe Thr Gly Lys Gly Leu Ser Phe Gly Gly Ser Leu Ile Arg Pro
195 200 205
Glu Ala Thr Gly Tyr Gly Leu Val Tyr Phe Thr Glu Ala Met Leu Lys
210 215 220
Arg His Gly Met Gly Phe Glu Gly Met Arg Val Ser Val Ser Gly Ser
225 230 235 240
Gly Asn Val Ala Gln Tyr Ala Ile Glu Lys Ala Met Glu Phe Gly Ala
245 250 255
Arg Val Ile Thr Ala Ser Asp Ser Ser Gly Thr Val Val Asp Glu Ser
260 265 270
Gly Phe Thr Lys Glu Lys Leu Ala Arg Leu Ile Glu Ile Lys Ala Ser
275 280 285
Arg Asp Gly Arg Val Ala Asp Tyr Ala Lys Glu Phe Gly Leu Val Tyr
290 295 300
Leu Glu Gly Gln Gln Pro Trp Ser Leu Pro Val Asp Ile Ala Leu Pro
305 310 315 320
Cys Ala Thr Gln Asn Glu Leu Asp Val Asp Ala Ala His Gln Leu Ile
325 330 335
Ala Asn Gly Val Lys Ala Val Ala Glu Gly Ala Asn Met Pro Thr Thr
340 345 350
Ile Glu Ala Thr Glu Leu Phe Gln Gln Ala Gly Val Leu Phe Ala Pro
355 360 365
Gly Lys Ala Ala Asn Ala Gly Gly Val Ala Thr Ser Gly Leu Glu Met
370 375 380
Ala Gln Asn Ala Ala Arg Leu Gly Trp Lys Ala Glu Lys Val Asp Ala
385 390 395 400
Arg Leu His His Ile Met Leu Asp Ile His His Ala Cys Val Asp His
405 410 415
Gly Gly Glu Gly Glu Gln Thr Asn Tyr Val Gln Gly Ala Asn Ile Ala
420 425 430
Gly Phe Val Lys Val Ala Asp Ala Met Leu Ala Gln Gly Val Ile
435 440 445

1489 bases

nucleic acid

single

linear

DNA

not provided

12
TCTAGAACAA TGGATCAGAC ATATTCTCTG GAGTCATTCC TCAACCATGT CCAAAAGCGC 60
GACCCGAATC AAACCGAGTT CGCGCAAGCC GTTCGTGAAG TAATGACCAC ACTCTGGCCT 120
TTTCTTGAAC AAAATCCAAA ATATCGCCAG ATGTCATTAC TGGAGCGTCT GGTTGAACCG 180
GAGCGCGTGA TCCAGTTTCG CGTGGTATGG GTTGATGATC GCAACCAGAT ACAGGTCAAC 240
CGTGCATGGC GTGTGCAGTT CAGCTCTGCC ATCGGCCCGT ACAAAGGCGG TATGCGCTTC 300
CATCCGTCAG TTAACCTTTC CATTCTCAAA TTCCTCGGCT TTGAACAAAC CTTCAAAAAT 360
GCCCTGACTA CTCTGCCGAT GGGCGGTGGT AAAGGCGGCA GCGATTTCGA TCCGAAAGGA 420
AAAAGCGAAG GTGAAGTGAT GCGTTTTTGC CAGGCGCTGA TGACTGAACT GTATCGCCAC 480
CTGGGCGCGG ATACCGACGT TCCGGCAGGT GATATCGGGG TTGGTGGTCG TGAAGTCGGC 540
TTTATGGCGG GGATGATGAA AAAGCTCTCC AACAATACCG CCTGCGTCTT CACCGGTAAG 600
GGCCTTTCAT TTGGCGGCAG TCTTATTCGC CCGGAAGCTA CCGGCTACGG TCTGGTTTAT 660
TTCACAGAAG CAATGCTAAA ACGCCACGGT ATGGGTTTTG AAGGGATGCG CGTTTCCGTT 720
TCTGGCTCCG GCAACGTCGC CCAGTACGCT ATCGAAAAAG CGATGGAATT TGGTGCTCGT 780
GTGATCACTG CGTCAGACTC CAGCGGCACT GTAGTTGATG AAAGCGGATT CACGAAAGAG 840
AAACTGGCAC GTCTTATCGA AATCAAAGCC AGCCGCGATG GTCGAGTGGC AGATTACGCC 900
AAAGAATTTG GTCTGGTCTA TCTCGAAGGC CAACAGCCGT GGTCTCTACC GGTTGATATC 960
GCCCTGCCTT GCGCCACCCA GAATGAACTG GATGTTGACG CCGCGCATCA GCTTATCGCT 1020
AATGGCGTTA AAGCCGTCGC CGAAGGGGCA AATATGCCGA CCACCATCGA AGCGACTGAA 1080
CTGTTCCAGC AGGCAGGCGT ACTATTTGCA CCGGGTAAAG CGGCTAATGC TGGTGGCGTC 1140
GCTACATCGG GCCTGGAAAT GGCACAAAAC GCTGCGCGCC TGGGCTGGAA AGCCGAGAAA 1200
GTTGACGCAC GTTTGCATCA CATCATGCTG GATATCCACC ATGCCTGTGT TGACCATGGT 1260
GGTGAAGGTG AGCAAACCAA CTACGTGCAG GGCGCGAACA TTGCCGGTTT TGTGAAGGTT 1320
GCCGATGCGA TGCTGGCGCA GGGTGTGATT TAAGTTGTAA ATGCCTGATG GCGCTACGCT 1380
TATCAGGCCT ACAAATGGGC ACAATTCATT GCAGTTACGC TCTAATGTAG GCCGGGCAAG 1440
CGCAGCGCCC CCGGCAAAAT TTCAGGCGTT TATGAGTATT TAAGAGCTC 1489

1482 bases

nucleic acid

single

linear

DNA

not provided

13
GCATGCATCA GACATATTCT CTGGAGTCAT TCCTCAACCA TGTCCAAAAG CGCGACCCGA 60
ATCAAACCGA GTTCGCGCAA GCCGTTCGTG AAGTAATGAC CACACTCTGG CCTTTTCTTG 120
AACAAAATCC AAAATATCGC CAGATGTCAT TACTGGAGCG TCTGGTTGAA CCGGAGCGCG 180
TGATCCAGTT TCGCGTGGTA TGGGTTGATG ATCGCAACCA GATACAGGTC AACCGTGCAT 240
GGCGTGTGCA GTTCAGCTCT GCCATCGGCC CGTACAAAGG CGGTATGCGC TTCCATCCGT 300
CAGTTAACCT TTCCATTCTC AAATTCCTCG GCTTTGAACA AACCTTCAAA AATGCCCTGA 360
CTACTCTGCC GATGGGCGGT GGTAAAGGCG GCAGCGATTT CGATCCGAAA GGAAAAAGCG 420
AAGGTGAAGT GATGCGTTTT TGCCAGGCGC TGATGACTGA ACTGTATCGC CACCTGGGCG 480
CGGATACCGA CGTTCCGGCA GGTGATATCG GGGTTGGTGG TCGTGAAGTC GGCTTTATGG 540
CGGGGATGAT GAAAAAGCTC TCCAACAATA CCGCCTGCGT CTTCACCGGT AAGGGCCTTT 600
CATTTGGCGG CAGTCTTATT CGCCCGGAAG CTACCGGCTA CGGTCTGGTT TATTTCACAG 660
AAGCAATGCT AAAACGCCAC GGTATGGGTT TTGAAGGGAT GCGCGTTTCC GTTTCTGGCT 720
CCGGCAACGT CGCCCAGTAC GCTATCGAAA AAGCGATGGA ATTTGGTGCT CGTGTGATCA 780
CTGCGTCAGA CTCCAGCGGC ACTGTAGTTG ATGAAAGCGG ATTCACGAAA GAGAAACTGG 840
CACGTCTTAT CGAAATCAAA GCCAGCCGCG ATGGTCGAGT GGCAGATTAC GCCAAAGAAT 900
TTGGTCTGGT CTATCTCGAA GGCCAACAGC CGTGGTCTCT ACCGGTTGAT ATCGCCCTGC 960
CTTGCGCCAC CCAGAATGAA CTGGATGTTG ACGCCGCGCA TCAGCTTATC GCTAATGGCG 1020
TTAAAGCCGT CGCCGAAGGG GCAAATATGC CGACCACCAT CGAAGCGACT GAACTGTTCC 1080
AGCAGGCAGG CGTACTATTT GCACCGGGTA AAGCGGCTAA TGCTGGTGGC GTCGCTACAT 1140
CGGGCCTGGA AATGGCACAA AACGCTGCGC GCCTGGGCTG GAAAGCCGAG AAAGTTGACG 1200
CACGTTTGCA TCACATCATG CTGGATATCC ACCATGCCTG TGTTGACCAT GGTGGTGAAG 1260
GTGAGCAAAC CAACTACGTG CAGGGCGCGA ACATTGCCGG TTTTGTGAAG GTTGCCGATG 1320
CGATGCTGGC GCAGGGTGTG ATTTAAGTTG TAAATGCCTG ATGGCGCTAC GCTTATCAGG 1380
CCTACAAATG GGCACAATTC ATTGCAGTTA CGCTCTAATG TAGGCCGGGC AAGCGCAGCG 1440
CCCCCGGCAA AATTTCAGGC GTTTATGAGT ATTTAAGAGC TC 1482

1501 bases

nucleic acid

single

linear

DNA

not provided

14
CTGCAGGTCG ACTCTAGAAC AATGGATCAG ACATATTCTC TGGAGTCATT CCTCAACCAT 60
GTCCAAAAGC GCGACCCGAA TCAAACCGAG TTCGCGCAAG CCGTTCGTGA AGTAATGACC 120
ACACTCTGGC CTTTTCTTGA ACAAAATCCA AAATATCGCC AGATGTCATT ACTGGAGCGT 180
CTGGTTGAAC CGGAGCGCGT GATCCAGTTT CGCGTGGTAT GGGTTGATGA TCGCAACCAG 240
ATACAGGTCA ACCGTGCATG GCGTGTGCAG TTCAGCTCTG CCATCGGCCC GTACAAAGGC 300
GGTATGCGCT TCCATCCGTC AGTTAACCTT TCCATTCTCA AATTCCTCGG CTTTGAACAA 360
ACCTTCAAAA ATGCCCTGAC TACTCTGCCG ATGGGCGGTG GTAAAGGCGG CAGCGATTTC 420
GATCCGAAAG GAAAAAGCGA AGGTGAAGTG ATGCGTTTTT GCCAGGCGCT GATGACTGAA 480
CTGTATCGCC ACCTGGGCGC GGATACCGAC GTTCCGGCAG GTGATATCGG GGTTGGTGGT 540
CGTGAAGTCG GCTTTATGGC GGGGATGATG AAAAAGCTCT CCAACAATAC CGCCTGCGTC 600
TTCACCGGTA AGGGCCTTTC ATTTGGCGGC AGTCTTATTC GCCCGGAAGC TACCGGCTAC 660
GGTCTGGTTT ATTTCACAGA AGCAATGCTA AAACGCCACG GTATGGGTTT TGAAGGGATG 720
CGCGTTTCCG TTTCTGGCTC CGGCAACGTC GCCCAGTACG CTATCGAAAA AGCGATGGAA 780
TTTGGTGCTC GTGTGATCAC TGCGTCAGAC TCCAGCGGCA CTGTAGTTGA TGAAAGCGGA 840
TTCACGAAAG AGAAACTGGC ACGTCTTATC GAAATCAAAG CCAGCCGCGA TGGTCGAGTG 900
GCAGATTACG CCAAAGAATT TGGTCTGGTC TATCTCGAAG GCCAACAGCC GTGGTCTCTA 960
CCGGTTGATA TCGCCCTGCC TTGCGCCACC CAGAATGAAC TGGATGTTGA CGCCGCGCAT 1020
CAGCTTATCG CTAATGGCGT TAAAGCCGTC GCCGAAGGGG CAAATATGCC GACCACCATC 1080
GAAGCGACTG AACTGTTCCA GCAGGCAGGC GTACTATTTG CACCGGGTAA AGCGGCTAAT 1140
GCTGGTGGCG TCGCTACATC GGGCCTGGAA ATGGCACAAA ACGCTGCGCG CCTGGGCTGG 1200
AAAGCCGAGA AAGTTGACGC ACGTTTGCAT CACATCATGC TGGATATCCA CCATGCCTGT 1260
GTTGACCATG GTGGTGAAGG TGAGCAAACC AACTACGTGC AGGGCGCGAA CATTGCCGGT 1320
TTTGTGAAGG TTGCCGATGC GATGCTGGCG CAGGGTGTGA TTTAAGTTGT AAATGCCTGA 1380
TGGCGCTACG CTTATCAGGC CTACAAATGG GCACAATTCA TTGCAGTTAC GCTCTAATGT 1440
AGGCCGGGCA AGCGCAGCGC CCCCGGCAAA ATTTCAGGCG TTTATGAGTA TTTAAGAGCT 1500
C 1501

20 bases

nucleic acid

single

linear

DNA

not provided

15
AATTCGAACC CCTTCGCATG 20

12 bases

nucleic acid

single

linear

DNA

not provided

16
CGAAGGGGTT CG 12

29 bases

nucleic acid

single

linear

DNA

not provided

17
GGTTTTATAT GCATGCATCA GACATATTC 29

Claims

1. A method of growing a transgenic crop plant in the presence of phosphinothricin herbicide, wherein the growth of said transgenic crop plant is resistant to an herbicide of the phosphinothricin class due to being transformed with a DNA sequence encoding a bacterial NADP-specific glutamate dehydrogenase enzyme, said enzyme conferring on said transgenic crop plant the ability to grow in the presence of an amount of said herbicide of the phosphinothricin class sufficient to inhibit growth of a crop plant not transformed with said DNA sequence, said method comprising: applying to a field in which said transgenic crop plant is growing an effective amount of said herbicide of the phosphinothricin class sufficient to inhibit growth of said crop plant not transformed with said DNA sequence.
2. A method according to claim 1 wherein said DNA sequence comprises the Kozac consensus sequence.
3. A method according to claim 1 wherein applying said herbicide of the phosphinothricin class is combined with applying to said field an effective amount of a second herbicide.
4. A method according to claim 1 wherein said crop plant is selected from the group consisting of corn, cotton, brassica, soybean, wheat and rice.
5. Transgenic plant cells and progeny thereof comprising an expression cassette comprising:1) a transcription initiation region functional in the plant cells; 2) a DNA sequence that encodes a bacterial NADP-specific GDH enzyme; and 3) a transcription termination region functional in said plant cells, wherein said expression cassette imparts a detectable level of herbicide resistance to the phosphinothricin class of herbicides.
6. Cells according to claim 5 wherein at least one of said transcription region and said transcription termination region is not naturally associated with said DNA sequence.
7. Cells according to claim 5 wherein said DNA sequence is from E. coli.
8. Cells according to claim 5 wherein said DNA sequence is modified to enhance expression in plant cells.
9. Cells according to claim 5 wherein the DNA sequence of SEQ ID NO:11 encodes the amino acid sequence of.
10. Cells according to claim 5 wherein the expression cassette comprises a chloroplast transit peptide adapted to target the enzyme to the chloroplasts.
11. Cells according to claim 5 wherein said transcription initiation region is constitutive.
12. Cells according to claim 5 wherein said transcription initiation region is organ specific.
13. A cell culture of cells according to claim 5 wherein said expression cassette further comprising a marker gene wherein the cells grow in a culture medium which includes a herbicide which is in the phosphinothricin class.
14. A cell culture of cells according to claim 5 further comprising a marker gene that is capable of growth in a culture medium which includes a herbicide which is not a phosphinothricin class.
15. A cell culture of claim 13 wherein said herbicide is bialaphos.
16. A transgenic plant wherein the growth of said transgenic plant is resistant to an herbicide of the phosphinothricin class due to being transformed with a gene encoding a bacterial NADP-specific glutamate dehydrogenase enzyme, said enzyme conferring on said transgenic plant the ability to grow in the presence of an amount of a phosphinothricin class herbicide sufficient to inhibit growth of said plant not transformed with said gene.
17. A transgenic plant according to claim 16 wherein said plant is a dicot.
18. A transgenic plant according to claim 16 wherein said plant is a monocot.
19. A transgenic plant according to claim 18 wherein said plant is Zea mays.
20. A transgenic plant according to claim 17 wherein said plant is selected from the group consisting of brassica, cotton, soybean and tobacco.
21. A transgenic plant according to claim 16 wherein said plant produces seeds and said plant is also transformed with a gene that alters a property of said seeds selected from the group consisting of the protein content and the oil content of said seeds.
22. A transformed corn plant containing a bacterial NADP-specific glutamate dehydrogenase gene.
23. A plant containing a transgene encoding a bacterial NADP-specific glutamate dehydrogenase gene.
24. Cells according to claim 5 wherein the DNA sequence is SEQ ID NO:1.
25. Cells according to claim 5 wherein the DNA sequence is SEQ ID NO:2.
26. A transformed corn plant according to claim 22 that is resistant to a herbacide of the phosphinothricin class, wherein said plant further contains a second transgene.
27. A method of growing a transgenic crop plant in the presence of bialaphos herbicide, wherein the growth of said transgenic crop plant is resistant to bialaphos due to being transformed with a gene encoding a bacterial NADP-specific glutamate dehydrogenase enzyme, said enzyme conferring on said transgenic crop plant the ability to grow in the presence of an amount of bialaphos sufficient to inhibit growth of a crop plant not transformed with said gene, said method comprising: applying to a field in which said transgenic crop plant is growing an effective amount of bialaphos sufficient to inhibit growth of said crop plant not transformed with said gene.
28. Transgenic plant cells and progeny thereof comprising an expression cassette comprising:1) a transcription initiation region functional in said plant cells, 2) a DNA sequence that encodes a bacterial NADP-specific glutamate dehydrogenase enzyme, and 3) a transcription termination region functional in said plant cells; wherein said expression cassette imparts a detectable level of resistance to bialaphos.
29. A transgenic plant, wherein the growth of said transgenic plant is resistant to bialaphos due to being transformed with a gene encoding a bacterial NADP-specific glutamate dehydrogenase enzyme, said enzyme conferring on said transgenic plant the ability to grow in the presence of an amount of bialaphos sufficient to inhibit growth of a plant not transformed with said gene.
30. A method of growing a transgenic crop plant in the presence of glufosinate herbicide, wherein the growth of said transgenic crop plant is resistant to glufosinate due to being transformed with a gene encoding a bacterial NADP-specific glutamate dehydrogenase enzyme, said enzyme conferring on said transgenic crop plant the ability to grow in the presence of an amount of glufosinate sufficient to inhibit growth of a crop plant not transformed with said gene, said method comprising: applying to a field in which said transgenic crop plant is growing an effective amount of glufosinate sufficient to inhibit growth of said crop plant not transformed with said gene.
31. Transgenic plant cells and progeny thereof comprising an expression cassette comprising:1) a transcription initiation region functional in said plant cells, 2) a DNA sequence that encodes a bacterial NADP-specific glutamate dehydrogenase enzyme, and 3) a transcription termination region functional in said plant cells; wherein said expression cassette imparts a detectable level of resistance to glufosinate.
32. A transgenic plant, wherein the growth of said transgenic plant is resistant to glufosinate due to being transformed with a gene encoding a bacterial NADP-specific glutamate dehydrogenase enzyme, said enzyme conferring on said transgenic plant the ability to grow in the presence of an amount of glufosinate sufficient to inhibit growth of a plant not transformed with said gene.

Parent Case Info

This application is copending and claims the priority from U.S. provisional application, 60/021,058 having a Jul. 2, 1996 filing date.

US Referenced Citations (1)

Number	Name	Date	Kind
5998700	Lightfoot et al.	Dec 1999

Foreign Referenced Citations (3)

Number	Date	Country
2173730	Apr 1995	CA
2232542	Apr 1997	CA
WO 9509911	Apr 1995	WO

Non-Patent Literature Citations (50)

Entry
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Loulakakis et al., “Regulation of glutamate dehydrogenase and glutamine synthetase in avocado fruit during development and ripening”, Plant Physiol. 106: 217-222 (1994).
Loulakakis et al., “Ammonium-induced increase in NADH-glutamate dehydrogenase activity is caused by de-novo synthesis of the a-subunit”, Planta 1987: 322-327 (1992).
Cammaerts and Jacobs, “A study of the role of glutamate dehydrogenase in the nitrogen metabolism of Arabidopsis thaliana”, Planta 163: 517-526 (1985).
Robinson et al., “The role of glutamate dehydrogenase in plant nitrogen metabolism”, Plant Physiol. 95: 509-516 (1991).
Srivastave and Singh, “Role and regulation of L-glutamate dehydrogenase activity in higher plants”, Phytochemistry, 26: 597-610 (1987).
Oaks, “Primary nitrogen assimilation in higher plants and its regulation”, Can. J. Botany 72: 739-750 (1994).
Joy et al., “Assimilation of nitrogen in mutants lacking enzymes of the glutamate synthase cycle”, J. of Exp. Botany, 43: 139-145 (1992).
Stewart et al., “Evidence that glutamate dehydrogenase plays a role in the oxidative deamination of glutamate in seedlings of Zea mays L.”, Aust. J. Plant Physiol., 22 000-000 (1995).
Wooton and McPherson, “Genes of nitrate and ammonium assimilation”, The Genetic Manipulation of Plants and its Application to Agriculture, pp. 89-114 (1984).
McPherson and Wooton, “Complete nucleotide sequence of Escherichia coli gdhA gene”, Nucl. Acids Res. 11: 5257-5266 (1983).
Windass et al., “Improved conversion of methanol to single-cell protein by Methylophilus methylotrophus”, Nature 287: 396-401 (1980).
Lightfoot et al., “Expression of the Escherichia coli glutamate dehydrogenase gene in the cyanobacterium Synechococcus PCC6301 causes ammonium tolerance”, Plant Mol. Biol. 11: 335-344 (1988).
Cao et al., “Ammonium inhibition of Arabidopsis root growth can be reversed by potassium and by auxin resistance mutations aux1, axr1, and axr2(1)”, Plant Physiol. 102; 983-989 (1993).
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Morris et al., “Photorespiratory ammonia does not inhibit photosynthesis in glutamate synthase mutants of Arabidopsis”, Plant Physiol. 89: 498-500 (1989).
Lacuesta et al., “Temporal study of the effect of phosphinothricin on the activity of glutamine synthetase, glutamate dehydrogenase and nitrate reductase in Medicago sativa L.”, J. Plant Physiol. 136: 410-414 (1990).
Sakakibara et al., “Isolation and characterization of a cDNA that encodes maize glutamate dehydrogenase”, Plant Cell Physiosl. 36: 789-797 (1995).
Magalhaes et al., “Kinetics of 15NH4+ assimilation on Zea mays”, Plant Physiol. 94, 647-656 (1990).
Doehlert and Lambert “Metabolic characteristics associated with starch, protein, and deposition in developing maize kernels”, Crop Sci. 31:151-157 (1991).
Britton et al., “Structural relationship between the hexameric and tetrameric family of glutamate dehydrogenases”, Eur. J. Biochem. 209: 851-859 (1992).
Cock et al., “A nuclear gene with many introns encoding ammonium-inducible chloroplastic NADP-specific glutamate dehydrogenase(s) in Chlorella sorokiniana”, Plant Nol. Biol. 17: 1023-1044 (1991).
Miller et al., “Alternative splicing of a precursor-mRNA encoding by the Chlorella sorokiniana NADP-specific glutamate dehydrogenase gene yields mRNA for precursor proteins of isozyme subunits with different ammonium affinities”, Plant Mol. Biol. 37: 243-263 (1998).
Lea, P.J. et al., “The Enzymology and Metabolism of Glutamate, and Asparagine”, in Miflin, B.J. and Lea, P.J., eds., The Biochemistry of Plants, vol. 16, Chap. 4, pp. 121-159, Academic Press, 1990.
Wootton, J.C. (1983) “Reassessment of ammonium-ion affinities of NADP-specific glutamate dehydrogenases” Biochem. J. 205:527-531.
GenBank listing for “C. sorokiniana NADP-gdh mRNA for NADP-specific glutamate dehydrogenase”.
Loulakakis et al. “Regulation of Glutamate Dehydrogenase and Glutamine Synthetase in Avocado Fruit during Development and Ripening.” Plant Physiol. 106:217-222 (1994).
Loulakakis et al. “Ammonium-induced increase in NADH-glutamate dehydrogenase activity is caused by de-novo synthesis of the a-subunit.” Planta 1987: 322-327 (1992).
Cammaerts and Jacobs. “A study of the role of glutamate dehydrogenase in the nitrogen metabolism of Arabidopsis thaliana.” Planta 163: 517-526 (1985).
Robinson, et al. “The Role of Glutamate Dehydrogenase in Plant Nitrogen Metabolism.” Plant Physiol. 95: 509-516 (1991).
Srivastave and Singh. “Role and Regulation of L-Glutamate Dehydrogenase Activity in Higher Plants.” Phytochemistry, vol. 26, No. 3., pp. 597-610 (1987).
Oaks. “Primary nitrogen assimilation in higher plants and its regulation.” Can. J. Bot. 72: 739-750 (1994).
Joy, et al. “Assimilation of Nitrogen in Mutants Lacking Enzymes of the Glutamate Synthase Cycle.” Journal of Experimental Botany, vol, 43, No. 247, pp. 139-145 (1992).
Stewart, et al. “Evidence that Glutamate Dehydrogenase Plays a Role in the Oxidative Deamination of Glutamate in Seedlings of Zea mays L.” Aust. J. Plant Physiol. 22 000-000 (1995).
Wooton and McPherson. “Genes of Nitrate and Ammonium Assimilation”. The Genetic Manipulation of Plants and its Application to Agriculture, pp. 89-114 (1984).
Wooton and McPherson. “Complete nucleotide sequence of the Escherichia coli gdhA gene.” Nucleic Acids Research, vol. 11 No. 15 (1983).
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	Number	Date	Country
	60/021058	Jul 1996	US

Plants containing the gdhA gene and methods of use thereof

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