WO2005017114A2 - Method of increasing metabolism and stress tolerance in a plant - Google Patents

Abstract

The present invention provides a method and DNA molecules that when expressed in a plant produces transgenic plants with improved agronomic characteristics. The invention includes plant expression vectors comprising the DNA molecules, where the DNA molecules encode proteins that are related to plant transcription factors and plants containing such DNA molecules.

Description

Method for increasing metabolism and stress tolerance in a plant

This application claims priority from US provisional application having serial number 60/494,397 filed August 12, 2003, the entirety of which is hereby incorporated by reference hereto. Field of Invention Described herein are inventions in the field of plant molecular biology and plant genetic engineering. In particular, DNA constructs encoding a transcription factor and transgenic plants containing such DNA constructs are provided. BACKGROUND OF THE INVENTION Recent advances in genetic engineering have provided the prerequisite tools to transform plants to contain foreign (also referred to as "heterogenous or heterologous") genes or improved endogenous genes. The introduction of such a gene in a plant would desirably lead to an improvement of an already existing characteristic in plant tissues or introduction of a novel characteristic. It is presently possible to produce plants with unique physiological and biochemical traits and characteristics of high agronomic importance. Particularly desirable traits that are targets for crop plant improvement include those that play an essential role in plant growth and development; crop yield potential and stability; and crop quality and composition. These improvements may be achieved by genetically modifying a crop plant for improved photosynthetic rate and increased drought and osmotic stress tolerance. Many biological functions in plants and other living organisms are regulated in a rhythmic manner as a function of night and day cycles. Rhythmic regulation of biological function in living organism is often referred as "circadian rhythm" or "circadian clock". Genes involved in photosynthetic pathways have been proposed to be a universal mechanism for sensing and responding to the light environment. The phase of circadian rhythms can be set by light and dark transition, but these rhythms can persist even in the absence of such external time cues. The importance of such rhythms in plant development was long recognized, however no circadian clock components were recognized until the recent past (Wang and Tobin, Cell 98: 1207- 1217, 1997). Current work in this area is directed towards the understanding of circadian clocks as a function of gene or genes. One such gene is Circadian Clock Associated-1 (CCAl). CCAl encodes a MYB -related transcription factor protein involved in the phytochrome induction of a light-harvesting chlorophyll a/b-protein (Lhcb) gene. In its native state, the CCAl transcript is transiently induced by phytochrome and oscillates with a circadian rhythm. It has been shown that overexpression of the CCAl protein in transgenic Arabidopsis plants abolished the circadian rhythm of other genes with dramatically different phases. As evidenced by the fact that CCAl protein level was similar to peak levels in wild-type plants, it was determined that overexpression of CCAl in Arabidopsis alters the circadian rhythm of other genes (such as Lhcbl*l, CCR2 and CAT3) leading to late flowering and elongated hypocotyls in Arabidopsis plants. Furthermore, the expression of both endogenous CCAl and the related LHY gene was suppressed by over expression of non native CCAl as reported by Wang and Tobin (Cell 93: 1207-1217, 1998) Earlier studies on the effect of CCAl overexpression in Arabidopsis largely focused on a few genes and the delayed flowering-time. Therefore, the range of genes regulated by native CCAl is not yet known. Because phytochrome is known to regulate some key photosynthetic genes, and because a number of key photosynthetic genes are known to be diurnally regulated, there is potential for CCAl to regulate significant parts of the photosynthetic pathway as a method that may enhance photosynthesis and ultimately the yield of crop plants. Photosynthesis, carbon assimilation and external stresses are known to be limiting factors in the yield of crop plants. Previous studies have made efforts to enhance photosynthesis in plants using over expression of transgenes of individual photosynthetic genes. However, due to the complex photosynthetic pathway, the rate- limiting step in the pathway has been difficult to determine. Many studies have been done using a "knockdown" approach to reduce photosynthesis and identify key steps along the pathway (Strand A, Zrenner R, Trevanion S, Stitt M, Gustafsson P, Gardestrom P, Plant Journal, 23 (6): 759-770, 2000; Strand A, Hurry V, Henkes S, Huner N, Gustafsson P, Gardestrom P, Stitt M, Plant Physiology, 119 (4): 1387-1397, 1999). Others have used over-expression studies of particular genes to increase photosynthesis e.g. PhyB, SBPase/FBPase, and trehalose phosphate synthase with limited success to date. Many of the characteristics and properties of an organism result from the coordinated expression of subsets of genes. Moreover, a need continues to exist in the field of plant biotechnology for novel solutions permitting plants to increase photosynthesis and/or tolerance to environmental stresses such that the overall yield of a crop plant is improved. The knowledge-based manipulation of transcription factor activity offers the possibility of modulating the expression of genes or biological pathways for generating novel traits in an organism in an efficient manner.

SUMMARY OF THE INVENTION Described herein is a method of providing an improved or new agriculturally desirable trait to a plant by ectopically expressing a transcription factor capable of providing one or more of such traits to the plant. In one embodiment the transcription factor is the CCAl protein as described herein, its homologs, orthologs, analogs or variants thereof and such protein is expressed in the plant at least during its vegetative growth phases. Another embodiment of the present invention provides a method for improving the agronomic characteristics of a plant by transforming a plant cell with a plant expressible DNA construct comprising a DNA polynucleotide that encodes a protein selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16 and SEQ ID NO: 18, or a protein substantially homologous thereto to obtain a transformed plant cell and regenerating such transformed plant cell into a transgenic plant containing the DNA construct. The transgenic plants are then screened for the desired agronomic characteristics as compared to a plant of the same species as said transgenic plant that does not contain said DNA construct and a transgenic plant containing at least one or more of said improved agronomic characteristics is selected. The DNA construct comprising a DNA molecule that encodes a protein substantially homologous to a protein selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16 and SEQ ID NO: 18, may be inserted into a plant cell and used to produce a fertile transgenic plant containing the DNA molecule; wherein the fertile transgenic plant exhibits at least one of the traits selected from the group consisting of a higher rate of photosynthesis, a higher rate of higher carbon assimilation , and increased tolerance to environmental stress, as compared to a plant of a same plant species not transformed to contain the said DNA molecule. In another aspect of the invention a DNA construct is provided that contains a promoter that is plant promoter, wherein said promoter drives transcription of an operably linked DNA molecule selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 15, SEQ ID NO: 17, and SEQ ID NO: 19 or DNA molecules substantially homologous thereto. In another aspect of the invention a transgenic plant, seed and/or hybrid seed containing a DNA molecule of the present invention are provided, wherein the transgenic plant, seed or hybrid seed exhibit at least one of the traits of a higher rate of ^•photosynthesis, higher carbon assimilation, and increased tolerance to environmental stress, particularly drought stress. The present invention also provides a transformed plant comprising in its genome a polynucleic acid molecule with a 5' non-coding DNA sequence that functions in the cell to cause the production of an mRNA molecule; and that is operably linked to a structural polynucleotide molecule isolated from a plant, wherein .the structural polynucleotide molecule encodes a polypeptide with an amino acid sequence that has at least 70%, 75%, 80%, 85%, 90%, 95% or 98% sequence identity to a member selected from group consisting of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16 and SEQ ID NO: 18; and that is operably linked to a 3' non-translated DNA molecule that functions in said cell to cause termination of transcription.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows a plasmid map for plant transformation vector pMON 10098. Figure 2 shows a plasmid map for plant transformation vector pMON CCA-1. Figure 3 shows a plasmid map for plant transformation vector pMON 67289. Figure 4 shows a plasmid map for plant transformation vector pMON 67293. Figure 5 shows a plasmid map for plant transformation vector pMON 57231. Figure 6 shows a plasmid map for plant transformation vector pMON 56622. Figure 7 shows a plasmid map for plant transformation vector pMON 67278. Figure 8 shows a plasmid map for plant transformation vector pMON 67294. Figure 9 shows a plasmid map for plant transformation vector pMON 67288. Figure 10 shows a plasmid map for plant transformation vector pMON 67292. Figure 11 shows a plasmid map for plant transformation vector pMON 41124. Figure 12 shows a plasmid map for plant transformation vector PCGN 10947. Figure 13 shows a plasmid map for plant transformation vector pMON 73975. Figure 14 shows a plasmid map for plant transformation vector pMON 73979. Figure 15 shows a plasmid map for plant transformation vector pMON 41162. Figure 16 shows a plasmid map for plant transformation vector pMON 67250. Figure 17 shows a plasmid map for plant transformation vector pMON 67299. Figure 18 shows a plasmid map for plant transformation vector pMON 65154. Figure 19 shows a plasmid map for plant transformation vector pMON 72469. Figure 20 shows a plasmid map for plant transformation vector pMON 72472. Figure 21 shows a plasmid map for plant transformation vector pMON 73779.

DETAILED DESCRIPTION OF THE INVENTION

It has been found that transgenic plants expressing the transcription factor CCA-1 or DNA molecules substantially homologous thereto provide a higher rate of photosynthesis, increased carbon assimilation and/or increased tolerance to stress to the plant and thereby lead to increased yield of the plant, particularly grain yield. This property can also be used to enhance the quality and quantity of forage production of forage plants by regulating the ratio of vegetative to reproductive growth in a manner to increase the amount of vegetative biomass accumulate by the plant. The present invention is based, in part, on the identification of polynucleic acid molecules encoding polypeptides of the present invention from crop plants including maize, soybean, rice, canola, cotton, alfalfa and wheat and utilizing these molecules to improve agronomic characteristics of plants such as elevated rate of photosynthesis, increased metabolite content and increased stress tolerance by expression of polypeptides of the invention leading to enhancement in yield. One aspect of the present invention relates to isolated polynucleic acid molecules comprising a nucleotide sequence or complement thereof that encode a transcription factor or CCA-1 like proteins. These proteins when expressed in a plant can impart a significant yield increase characteristic to the plant when grown under field conditions. Polynucleotide or polypeptide molecules of the invention are plant transcription factors having CCA-1 like properties and their homologs, orthologs or paralogs. These molecules are identified by comparing SEQ ID NO:l or SEQ ID NO:2 with other nucleic acid or polypeptide sequences of plant cDNA molecules and developing an evolutionary relationship among them. Nucleic acid analysis to identify homologs, orthologs or paralogs and building phylogenetic trees there from is well known in the art. In a preferred embodiment, these molecules will encode a polypeptide from a crop plant having an amino acid sequence that has at least 70% sequence identity, or at least 75% or 80% sequence identity, or at least 85% or 90% sequence identity, or at least 95% sequence identity, or at least 98% sequence identity to a member selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16 and SEQ ID NO: 18. According to this invention, transgenic plants and seeds have incorporated into their genome, or transformed into their chloroplast or plastid genomes, a polynucleic acid molecule that comprises at least a structural nucleotide sequence that encodes a polypeptide having an amino acid sequence selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16 and SEQ ID NO: 18. The term "polynucleic acid molecule" as used herein means a deoxyribonucleic acid (DNA) molecule or ribonucleic acid (RNA) molecule. Both DNA and RNA molecules are constructed from nucleotides linked end to end, wherein each of the nucleotides contains a phosphate group, a sugar moiety, and either a purine or a pyrimidine base. Polynucleic acid molecules can be single or double-stranded polymers of nucleotides read from the 5' to the 3' end. Polynucleic acid molecules may also optionally contain synthetic, non-natural or altered nucleotide bases that permit correct read through by a polymerase and do not alter expression of a polypeptide encoded by that polynucleic acid molecule. The term "an isolated polynucleic acid molecule" as used herein, means a polynucleic acid molecule that is no longer accompanied by those materials with which it is associated in its natural state, or to a polynucleic acid molecule for which the structure of which is not identical to that of any of naturally occurring polynucleic acid molecule. It is also contemplated by the inventors that the isolated polynucleic acid molecules of the present invention also include known types of modifications. The term "nucleotide sequence" as used herein means the linear arrangement of nucleotides to form a polynucleotide of the sense and complementary strands of a polynucleic acid molecule as either individual single strands or in the duplex. As used herein both terms "a coding sequence" and "a structural polynucleotide molecule" mean a polynucleotide molecule that is translated into a polypeptide, usually via mRNA, when placed under the control of appropriate regulatory molecules. The boundaries of the coding sequence are determined by a translation start codon at the 5 '-terminus and a translation stop codon at the 3'- terminus. A coding sequence can include, but is not limited to, genomic DNA, cDNA, and recombinant polynucleotide sequences. The term " recombinant DNAs" as used herein means DNAs that contains a genetically engineered modification through manipulation via mutagenesis, restriction enzymes, and the like. The term "synthetic DNAs" as used herein means DNAs assembled from oligonucleotide building blocks that are chemically synthesized using procedures known to those skilled in the art. Both terms "polypeptide" and "protein", as used herein, mean a polymer composed of amino acids connected by peptide bonds. An amino acid unit in a polypeptide (or protein) is called a residue. The terms "polypeptide" and "protein" also applies to any amino acid polymers in which one or more amino acid residue is an artificial chemical analogue of a corresponding naturally occurring amino acid, as well as to any naturally occurring amino acid polymers. The essential nature of such analogues of naturally occurring amino acids is that, when incorporated into a polypeptide, that polypeptide is specifically reactive to antibodies elicited to the same polypeptide but consisting entirely of naturally occurring amino acids. It is well known in the art that proteins or polypeptides may undergo modification. Exemplary modifications are described in most basic texts, such as, for example, Proteins - Structure and Molecular Properties, 2nd ed., T. E. Creighton, W. H. Freeman and Company, New York (1993). Many detailed reviews are available on this subject, such as, for example, those provided by Wold, F., Post-translational Protein Modifications. Perspectives and Prospects, pp.1-12 in Post-translational Covalent Modification of Proteins, B. C. Johnson, Ed., Academic Press, New York (1983); Seifter et al., Meth. Enzymol. 182:626-M (1990) and Rattan et al., Protein Synthesis: Post-translational Modifications and Aging, Ann. N.Y. Acad. Sci. 663:48-62 (1992). The term "amino acid sequence" means the sequence of amino acids in a polypeptide (or protein) that is written starting with the amino-terminal (N-terminal) residue and ending with the carboxyl-terminal (C-terminal) residue. "Percentage of sequence identity" is determined by comparing two optimally aligned sequences over a comparison window, wherein the portion of the polynucleotide or amino acid sequence in the comparison window may comprise additions or deletions (i.e., gaps) as compared to the reference sequence (that does not comprise additions or deletions) for optimal alignment of the two sequences. The percentage is calculated by determining the number of positions at which the identical nucleic acid base or amino acid residue occurs in both sequences to yield the number of matched positions, dividing the number of matched positions by the total number of positions in the window of comparison and multiplying the result by 100 to yield the percentage of sequence identity. Terms "substantially identical", "substantially homologous" and "substantial identity", when used as reference to two polypeptide sequences or two polynucleotide sequences, means that one polypeptide sequence or one polynucleotide sequence has at least 70% sequence identity compared to the other polypeptide sequence or polynucleotide sequence as a reference sequence using the Gap program in the WISCONSIN PACKAGE version 10.0-UNIX from Genetics Computer Group, Inc. based on the method of Needleman and Wunsch (J. Mol. Biol. 48:443-453, 1970), using the set of default parameters for pairwise comparison (for amino acid sequence comparison: Gap Creation Penalty = 8, Gap Extension Penalty = 2; for nucleotide sequence comparison: Gap Creation Penalty = 50; Gap Extension Penalty = 3) or using the TBLASTN program in the BLAST 2.2.1 software suite (Altschul et al., Nucleic Acids Res. 25:3389-3402), using BLOSUM62 matrix (Henikoff and Henikoff, Proc. Natl. Acad. Sci. U.S.A. 89:10915-10919, 1992) and the set of default parameters for pair- wise comparison (gap creation cost = 11, gap extension cost = 1.) Polypeptides that are "substantially similar" share sequences as noted above except that residue positions that are not identical may differ by conservative amino acid changes. Conservative amino acid substitutions refer to the interchangeability of residues having similar side chains. "Conservative amino acid substitutions" mean substitutions of one or more amino acids in a native amino acid sequence with another amino acid(s) having similar side chains, resulting in a silent change. Conserved substitutes for an amino acid within a native amino acid sequence can be selected from other members of the group to which the naturally occurring amino acid belongs. For example, a group of amino acids having aliphatic side chains is glycine, alanine, valine, leucine, and isoleucine; a group of amino acids having aliphatic- hydroxyl side chains is serine and threonine; a group of amino acids having amide- containing side chains is asparagine and glutamine; a group of amino acids having aromatic side chains is phenylalanine, tyrosine, and tryptophan; a group of amino acids having basic side chains is lysine, arginine, and histidine; and a group of amino acids having sulfur-containing side chains is cysteine and methionine. Preferred conservative amino acids substitution groups are: valine-leucine, valine-isoleucine, phenylalanine-tyrosine, lysine-arginine, alanine-valine, aspartic acid-glutamic acid, and asparagine-glutamine. One skilled in the art will recognize that the values of the above substantial identity of nucleotide sequences can be appropriately adjusted to determine corresponding sequence identity of two nucleotide sequences encoding the polypeptides of the present invention by taking into account codon degeneracy, conservative amino acid substitutions, reading frame positioning and the like. Substantial identity of nucleotide sequences for these purposes normally means sequence identity of at least 70%. The term "codon degeneracy" means divergence in the genetic code permitting variation of the nucleotide sequence without affecting the amino acid sequence of an encoded polypeptide. The skilled artisan is well aware of the "codon-bias" exhibited by a specific host cell in usage of nucleotide codons to specify a given amino acid. Therefore, when synthesizing a gene for ectopic expression in a host cell, it is desirable to design the gene such that its frequency of codon usage approaches the frequency of codon usage of the host cell as observed in a codon usage table. The polynucleic acid molecules encoding a polypeptide of the present invention may be combined with other non-native, or "heterologous" sequences in a variety of ways. By "heterologous" sequences it is meant any sequence that is not naturally found joined to the nucleotide sequence encoding polypeptide of the present invention, including, for example, combinations of nucleotide sequences from the same plant that are not naturally found joined together, or the two sequences originate from two different species. The term "operably linked", as used in reference to a regulatory molecule and a structural polynucleotide molecule, means that the regulatory molecule causes regulated expression of the operably linked structural polynucleotide molecule. "Expression" means the transcription and stable accumulation of sense or antisense RNA derived from the polynucleic acid molecule of the present invention. Expression may also refer to translation of mRNA into a polypeptide. "Sense" RNA means RNA transcript that includes the mRNA and so can be translated into polypeptide or protein by the cell. "Antisense RNA" means a RNA transcript that is complementary to all or part of a target primary transcript or mRNA and that blocks the expression of a target gene (U.S. Patent No. 5,107,065, incorporated herein by reference). The complementarity of an antisense RNA may be with any part of the specific gene transcript, i.e., at the 5' non-coding sequence, 3' non-translated sequence, introns, or the coding sequence. "RNA transcript" means the product resulting from RNA polymerase-catalyzed transcription of a DNA sequence. When- the RNA transcript is a perfect complementary copy of the DNA sequence, it is referred to as the primary transcript or it may be a RNA sequence derived from post- transcriptional processing of the primary transcript and is referred to as the mature RNA. It is understood that to practice the present invention it is essential to introduce the selected polynucleotide molecule in a form that is capable of producing an active polypeptide molecule in a desired plant. Exogenous polynucleic acid molecules are transferred into a crop plant cell by use of a recombinant DNA construct (or vector) designed for such purpose. The DNA construct of the present invention can, in one embodiment, contain a promoter which causes the over expression of the polypeptide of the present invention, where "overexpression" means the expression of a polypeptide either not normally present in the host cell, or present in said host cell at a higher level than that normally expressed from the endogenous gene encoding said polypeptide. Promoters, which can cause the overexpression of the polypeptide of the present invention, are generally known in the art. The DNA construct of the present invention can, in another embodiment, contain a promoter which causes the ectopic expression of the polypeptide of the invention, where "ectopic expression" means the expression of a polypeptide in a cell type other than a cell type in which the polypeptide is normally expressed; at a time other than a time at which the polypeptide is normally expressed; or at a expression level other than the level at which the polypeptide normally is expressed. Promoters, which can cause ectopic expression of the polypeptide of the present invention, are generally known in the art. The expression level or pattern of the promoter of the DNA construct of the present invention may be modified to enhance its expression. Methods known to those of skill in the art can be used to insert enhancing elements (for example, sub-domains of the CaMV 35S promoter, Benfey et. al, 1990 EMBO J. 9: 1677-1684) into the 5' sequence of genes. In one embodiment, enhancing elements may be added to create a promoter, which encompasses the temporal and spatial expression of the native promoter of the gene of the present invention, but have quantitatively higher levels of expression. Similarly, tissue specific expression of the promoter can be accomplished through modifications of the 5' region of the promoter with elements determined to specifically activate or repress gene expression (for example, pollen specific elements, Eyal et al, 1995 Plant Cell 7: 373-384). The isolated polynucleic acid molecules of the present invention can also be used for gene suppression e.g. in antisense or RNA technology to suppress endogenous native gene expression. To accomplish this, a polynucleic acid molecule derived from a polynucleotide sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 15, SEQ ID NO: 17, and SEQ ID NO: 19 is cloned and operably linked to a promoter such that the antisense strand of RNA will be transcribed. The construct is then transformed into plants and the antisense strand of RNA is produced. The polynucleic acid segment to be introduced generally will be substantially identical to at least a portion of the endogenous gene or genes of the present invention to be repressed. The polynucleic acid sequence, however, need not be perfectly identical to inhibit expression. The recombinant vectors of the present invention can be designed such that the inhibitory effect applies to other genes within a family of genes exhibiting homology or substantial homology to the target gene. The term "a gene" means the segment of DNA that is involved in producing a polypeptide. Such segment of DNA may include regulatory molecules preceding (5' non-coding DNA molecules) and following (3' non-coding DNA molecules) the coding region, as well as intervening sequences (introns) between individual coding segments (exons). A "native gene" means a gene as found in nature with its own regulatory DNA sequences. "Chimeric gene" means any gene that is not a native gene, comprising regulatory and coding sequences that are not found together in nature. Accordingly, a chimeric gene may comprise regulatory sequences and coding sequences that are derived from different sources, or regulatory sequences and coding sequences derived from the same source, but arranged in a manner different than that found in nature. "Endogenous gene" means a native gene in its natural location in the genome of an organism. A "foreign gene" means a gene not normally found in the host organism, but that is introduced into the host organism by gene transfer. Foreign genes can comprise native genes inserted into a non-native organism, or chimeric genes. A "transgene" is a gene that has been introduced into the genome by a transformation procedure resulting in a transgenic organism. "Regulatory sequences" means polynucleotide molecules located upstream (5' non-coding sequences), within, or downstream (3' non-translated sequences) of a structural polynucleotide sequence, and that influence the transcription, RNA processing or stability, or translation of the associated structural polynucleotide sequence. Regulatory sequences may include promoters, translation leader sequences, introns, and polyadenylation recognition sequences. The term "promoter sequence" or "promoter" means a polynucleotide molecule that is capable of, when located in cis to a structural polynucleotide sequence encoding a polypeptide, functions in a way that directs expression of one or more mRNA molecules that encodes the polypeptide. Such promoter regions are typically found upstream of the trinucleotide, ATG, at the start site of a polypeptide coding region. Promoter molecules can also include DNA sequences from which transcription of transfer RNA (tRNA) or ribosomal RNA (rRNA) sequences are initiated. . The promoter sequence typically consists of proximal and more distal upstream elements, the latter elements often referred to as enhancers. Accordingly, an "enhancer" is a DNA sequence that can stimulate promoter activity and may be an innate element of the promoter or a heterologous element inserted to enhance the level or tissue-specificity of a promoter. Promoters may be derived in their entirety from a native gene, or be composed of different elements derived from different promoters found in nature, or even comprise synthetic DNA segments. It is understood by those skilled in the art that different promoters may direct the expression of a gene in different tissues or cell types, or at different stages of development, or in response to different environmental conditions. Promoters that are known or are found to cause transcription of DNA in plant cells can be used in the present invention. Such promoters may be obtained from a variety of sources such as plants and plant viruses. A number of promoters, including constitutive promoters, inducible promoters and tissue-specific promoters, that are active in plant cells have been described in the literature. It is preferred that the particular promoter selected should be capable of causing sufficient expression to result in the production of an effective amount of a polypeptide to cause the desired phenotype. In addition to promoters that are known to cause transcription of DNA in plant cells, other promoters may be identified for use in the current invention by screening a plant cDNA library for genes that are selectively or preferably expressed in the target tissues and then determine the promoter regions. The term "constitutive promoter" means a regulatory sequence that causes expression of a structural nucleotide sequence in most cells or tissues at most times. Constitutive promoters are active under most environmental conditions and states of development or cell differentiation. A variety of constitutive promoters are well known in the art. Examples of constitutive promoters that are active in plant cells include but are not limited to the nopaline synthase (NOS) promoters; the cauliflower mosaic virus (P-CaMV) 19S and 35S (U.S. Patent No. 5,858,642); the figwort mosaic virus promoter (P-FMV, U.S. Patent No. 6,051,753); and actin promoters, such as the rice actin promoter (P-Os.Actl, U.S. Patent No. 5,641,876). The term "inducible promoter" means a regulatory sequence that causes conditional expression of a structural nucleotide sequence under the influence of changing environmental conditions or developmental conditions. Examples of inducible promoters include but are not limited to the light-inducible promoter from the small subunit of ribulose- 1,5 -bis-phosphate carboxylase (ssRUBISCO); the drought-inducible promoter of maize (Busk et al., Plant J. 11 : 1285-1295, 1997), the cold, drought, and high salt inducible promoter from potato (Kirch, Plant Mol. Biol. 33:897-909, 1997), a nitrate-inducible promoter derived from the spinach nitrite reductase gene (Back et al., Plant Mol. Biol. 17:9, 1991), salicylic acid inducible promoter (Uknes et al., Plant Cell 5:159-169, 1993); Bi et al., Plant J. 8:235-245, 1995), the auxin-response elements El promoter fragment (AuxREs) in the soybean (Glycine max L.) (Liu et al., Plant Physiol. 115:397-407, 1997), the auxin-responsive Arabidopsis GST6 promoter (also responsive to salicylic acid and hydrogen peroxide) (Chen et al., Plant J. 10: 955-966, 1996), the auxin-inducible parC promoter from tobacco (Sakai et al., Plant Cell Physiol. 37:906-913, 1996), a plant biotin response element (Streit et al, Mol. Plant Microbe Interact. 10:933-937, 1997), the promoter responsive to the stress hormone abscisic acid (Sheen et al., Science 274:1900-1902, 1996), the maize In2-2 promoter activated by benzenesulfonamide herbicide safeners (De Veylder et al, Plant Cell Physiol. 38:568-577, 1997), a tetracycline-inducible promoter, such as the promoter for the Avena sativa L. (oat) arginine decarboxylase gene (Masgrau et al., Plant J. 11:465-473, 1997), and a salicylic acid-responsive element (Stange et al., Plant J. 11:1315-1324, 1997). The term "tissue-specific promoter" means a regulatory sequence that causes transcriptions or enhanced transcriptions of DNA in specific cells or tissues at specific times during plant development, such as in vegetative tissues or reproductive tissues. Examples of tissue-specific promoters under developmental control include promoters that initiate transcription only (or primarily only) in certain tissues, such as vegetative tissues, e.g., roots, leaves or stems, or reproductive tissues, such as fruit, ovules, seeds, pollen, pistils, flowers, or any embryonic tissue. Reproductive tissue specific promoters may be, e.g., ovule-specific, embryo-specific, endosperm-specific, integument-specific, seed coat-specific, pollen-specific, petal-specific, sepal-specific, or some combination thereof. One skilled in the art will recognize that a tissue- specific promoter may drive expression of operably linked DNA molecules in tissues other than the target tissue. Thus, as used herein a tissue-specific promoter is one that . drives expression preferentially in the target tissue, but may also lead to some expression in other tissues as well. A variety of promoters specifically active in vegetative tissues, such as leaves, stems, roots and tubers, can be used to express the polynucleic acid molecules of the present invention. Examples of tuber-specific promoters include, but are not limited to the class I and II patatin promoters (Bevan et al, EMBO J. 8:1899-1906, 1986; Koster-Topfer et al., Mol Gen Genet. 219:390-396, 1989; Mignery et al., Gene. 62:27-44, 1988; Jefferson et al., Plant Mol. Biol. 14: 995-1006, 1990), the promoter for the potato tuber ADPGPP genes, both the large and small subunits; the sucrose synthase promoter (Salanoubat and Belliard, Gene. 60:47-56, 1987; Salanoubat and Belliard, Gene. 84: 181-185, 1989), and the promoter for the major tuber proteins including the 22 kd protein complexes and proteinase inhibitors (Hannapel, Plant Physiol. 101:703-704, 1993). Examples of leaf-specific promoters include but are not limited to the ribulose biphosphate carboxylase (RBCS or RuBISCO) promoters (see, e.g., Matsuoka et al., Plant J. 6:311-319, 1994), the light harvesting chlorophyll a/b binding protein gene promoter (see, e.g., Shiina et al., Plant Physiol. 115:477- 483, 1997; Casal et al., Plant Physiol. 116:1533-1538, 1998), and the Arabidopsis thaliana myb-related gene promoter (Atmyb5) (Li et al, FEBS Lett. 379:117-121, 1996). Examples of root-specific promoter include, but are not limited to the promoter for the acid chitinase gene (Samac et al., Plant Mol. Biol. 25:587-596, 1994), the root specific subdomains of the CaMV35S promoter that have been identified (Lam et al., Proc. Natl. Acad. Sci. (U.S.A.) 86:7890-7894, 1989), the ORF13 promoter from Agrobacterium rhizogenes that exhibits high activity in roots (Hansen et al., Mol. Gen. Genet. 254:337-343 (1997), the promoter for the tobacco root-specific gene TobRB7 (Yamamoto et al, Plant Cell 3:371-382, 1991), and the root cell specific promoters reported by Conkling et al. (Conkling et al., Plant Physiol. 93:1203-1211, 1990). . - Another class of useful vegetative tissue-specific promoters is meristematic (root tip and shoot apex) promoters. For example, the "SHOOTMERISTEMLESS" and "SCARECROW" promoters, which are active in the developing shoot or root apical meristems can be used (Di Laurenzio et al., Cell 86:423- 433, 1996; Long, Nature 379:66-69, 1996). Another example of a useful promoter is that which controls the expression of 3-hydroxy-3- methylglutaryl coenzyme A reductase HMG2 gene, whose expression is restricted to meristematic and floral (secretory zone of the stigma, mature pollen grains, gynoecium vascular tissue, and fertilized ovules) tissues (see, e.g., Enjuto et al., Plant Cell. 7:517-527, 1995). Also another example of a useful promoter is that which controls the expression of knl-related genes from maize and other species that show meristem-specific expression (see, e.g., Granger et al., Plant Mol. Biol. 31:373-378, 1996; Kerstetter et al., Plant Cell 6:1877-1887, 1994; Hake et al., Philos. Trans. R. Soc. Lond. B. Biol. Sci. 350:45-51, 1995). Another example of a meristematic promoter is the Arabidopsis thaliana KNATl promoter. In the shoot apex, KNATl transcript is localized primarily to the shoot apical meristem; the expression of KNATl in the shoot meristem decreases during the floral transition and is restricted to the cortex of the inflorescence stem (see, e.g., Lincoln et al., Plant Cell 6:1859-1876, 1994). Suitable seed-specific promoters can be derived from the following genes: MAC1 from maize (Sheridan et al., Genetics 142:1009-1020, 1996; Cat3 from maize (GenBank No. L05934, Abler et al., Plant Mol. Biol. 22:10131-1038, 1993; vivparous-1 from Arabidopsis (Genbank No. U93215); Atimycl from Arabidopsis (Urao et al, Plant Mol. Biol. 32:571-57, 1996; Conceicao et al, Plant 5:493-505, 1994); napA from Brassica napus (GenBank No. J02798); the napin gene family from Brassica napus (Sjodahl et al., Planta 197:264-271,1995). The ovule-specific promoter for BEL1 gene can also be used (Reiser et al. Cell 83:735-742, 1995, GenBank No. U39944; Ray et al, Proc. Natl. Acad. Sci. USA 91:5761-5765, 1994). The egg and central cell specific MEA (FIS1) and FIS2 promoters are also useful reproductive tissue-specific promoters (Luo et al., Proc. Natl. Acad. Sci. USA, 97:10637-10642, 2000; Vielle-Calzada, et al., Genes Dev. 13:2971-2982, 1999). A maize pollen-specific promoter has been identified in maize (Guerrero et al., Mol. Gen. Genet. 224:161-168, 1990). Other genes specifically expressed in pollen have been described (see, e.g., Wakeley et al., Plant Mol. Biol. 37:187-192, 1998; Ficker et al., Mol. Gen. Genet. 257:132-142, 1998; Kulikauskas et al., Plant Mol. Biol. 34:809-814, 1997; Treacy et al., Plant Mol. Biol. 34:603-611, 1997). Promoters derived from genes encoding embryonic storage proteins, which includes the gene encoding the 2S storage protein from Brassica napus (Dasgupta et al., Gene 133:301-302, 1993); the 2s seed storage protein gene family from Arabidopsis; the gene encoding oleosin 20kD from Brassica napus (GenBank No. M63985); the genes encoding oleosin A (GenBank No. U09118) and oleosin B (GenBank No. U09119) from soybean; the gene encoding oleosin from Arabidopsis (GenBank No. Z17657); the gene encoding oleosin 18kD from maize (GenBank No. J05212, Lee, Plant Mol. Biol. 26:1981-1987, 1994); and the gene encoding low molecular weight sulphur rich protein from soybean (Choi et al., Mol. Gen. Genet. 246:266-268, 1995), can also be used. Promoters derived from zein encoding genes (including the 15 kD, 16 kD, 19 kD, 22 kD, 27 kD, and gamma genes, Pedersen et al., Cell 29:1015-1026, 1982) can be also used. The zeins are a group of storage proteins found in maize endosperm. Native promoters derived from genes of present invention or promoters from genes of the same biochemical or developmental pathway, which can express the polypeptides of the present invention in a temporal and spatial manner can also be used to practice the present invention. It is recognized that additional promoters that may be utilized are described, for example, in U.S. Patent Nos. 5,378,619, 5,391,725, 5,428,147, 5,447,858, 5,608,144, 5,608,144, 5,614,399, 5,633,441, 5,633,435, and 4,633,436, all of which are herein incorporated in their entirety. In addition, a tissue specific enhancer may be used (Fromm et al., The Plant Cell 1:977-984, 1989). It is further recognized that the exact boundaries of regulatory sequences may not be completely defined; DNA fragments of different lengths may have identical promoter activity. The construct of the present invention may also contain a "translation leader sequence." As used herein, "translation leader sequence" means a DNA sequence located between the promoter sequence of a gene and the coding sequence. The translation leader sequence is present in the fully processed mRNA upstream of the translation start sequence. The translation leader sequence may affect processing of the primary transcript to mRNA, mRNA stability or translation efficiency. Examples of translation leader sequences include maize and petunia heat shock protein leaders, plant virus coat protein leaders, plant rubisco gene leaders among others (Turner and Foster, Molecular Biotechnology 3:225, 1995). A further feature of a construct of the present invention is a "3' non-translated sequences" or "3' termination region." As used herein a "3' non-translated sequence" or "3' termination region" means DNA sequences located downstream of a structural nucleotide sequence and include sequences encoding polyadenylation and other regulatory signals capable of affecting mRNA processing or gene expression. The polyadenylation signal functions in plants to cause the addition of polyadenylate nucleotides to the 3' end of the mRNA precursor. The polyadenylation sequence can be derived from the natural gene, from a variety of plant genes, or from T-DNA. An example of the polyadenylation sequence is the nopaline synthase 3' sequence (nos 3'; Fraley et al., Proc. Natl. Acad. Sci. USA 80: 4803-4807, 1983). The use of different 3' non-translated sequences is exemplified by Ingelbrecht et al. (Plant Cell 1:671-680, 1989). The laboratory procedures in recombinant DNA technology used herein are those well known and commonly employed in the art. Standard techniques are used for cloning, DNA and RNA isolation, amplification and purification. Generally enzymatic reactions involving DNA ligase, DNA polymerase, restriction endonucleases and the like are performed according to the manufacturer's specifications. These techniques and various other techniques are generally performed according to Sambrook et al., Molecular Cloning - A Laboratory Manual, 2nd. ed., Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (1989), herein referred to as Sambrook et al., (1989). A "substantial portion" of a polynucleotide sequence comprises enough of the sequence to afford specific identification and/or isolation of a polynucleic acid molecule comprising the sequence. Polynucleotide sequences can be evaluated either manually by one skilled in the art, or by using computer-based sequence comparison and identification tools that employ algorithms such as BLAST (Basic Local Alignment Search Tool; Altschul et al. J Mol. Biol. 215:403-410, 1993; see also www.ncbi.nlm.nih.gov/BLAST/). In general, a sequence of thirty or more contiguous nucleotides is necessary in order to putatively identify a nucleotide sequence as homologous to a gene. Moreover, with respect to polynucleotide sequences, gene- specific oligonucleotide probes comprising 30 or more contiguous nucleotides may be used in sequence-dependent methods of gene identification (e.g., Southern ,. ^• hybridization) and isolation (e.g., in situ hybridization of bacterial colonies or bacteriophage plaques). In addition, short oligonucleotides of 12 or more nucleotides may be used as amplification primers in PCR in order to obtain a particular polynucleic acid molecule comprising the primers. The skilled artisan having the benefit of the polynucleic acid molecules as reported herein, may now use all or a substantial portion of the disclosed sequences for purposes known to those skilled in this art. Accordingly, the instant invention comprises the complete polynucleotide sequences as reported in the accompanying Sequence Listing, as well as substantial portions of those sequences as defined above. Isolation of polynucleic acid molecules encoding homologous polypeptides using polynucleotide sequence-dependent protocols is well known in the art. Examples of polynucleotide sequence-dependent protocols include, but are not limited to, methods of polynucleic acid molecule hybridization, and methods of DNA and RNA amplification as exemplified by various uses of polynucleic acid molecule amplification technologies (e.g., polymerase chain reaction, ligase chain reaction). For example, structural polynucleic acid molecules encoding additional polypeptides of the present invention, either as cDNAs or genomic DNAs, could be isolated directly by using all or a substantial portion of the polynucleic acid molecules of the present invention as DNA hybridization probes to screen cDNA or genomic libraries from any desired plant employing methodology well known to those skilled in the art. Methods for forming such libraries are well known in the art. Specific oligonucleotide probes based upon the polynucleic acid molecules of the present invention can be designed and synthesized by methods known in the art. Moreover, the entire sequences of the polynucleic acid molecules can be used directly to synthesize DNA probes by methods known to the skilled artisan such as random primer DNA labeling, nick translation, or end-labeling techniques, or RNA probes using available in vitro transcription systems. In addition, specific primers can be designed and used to amplify a part or all of the sequences. The resulting amplification products can be labeled directly during amplification reactions or labeled after amplification reactions, and used as probes to isolate full-length cDNA or genomic DNAs under conditions of appropriate stringency. Alternatively, the polynucleic acid molecules of interest can be isolated from a mixture of polynucleic acid molecules using amplification techniques. For instance, the disclosed polynucleic acid molecules may be used to define a pair of primers that can be used with the polymerase chain reaction (Mullis, et al., Cold Spring Harbor Symp. Quant. Biol. 51:263-273, 1986; EP 50,424; EP 84,796, EP 258,017, EP 237,362, EP 201,184; US 4,683,202; Erlich, US 4,582,788, and US 4,683,194, all of which are herein incorporated by reference in their entireties) to amplify and obtain any desired polynucleic acid molecule directly from mRNA, from cDNA, from genomic libraries or cDNA libraries. PCR and other in vitro amplification methods may also be useful, for example, to clone nucleotide sequences that encode for polypeptides to be expressed, to make polynucleic acid molecules to use as probes for detecting the presence of the desired mRNA in samples, for nucleic acid sequencing, or for other purposes. In addition, two short segments of the polynucleic acid molecules of the present invention may be used in polymerase chain reaction protocols to amplify longer polynucleic acid molecules encoding homologues of a polypeptide of the invention from DNA or RNA. For example, the skilled artisan can follow the RACE protocol (Frohman et al., Proc. Natl. Acad. Sci. USA 85:8998, 1988) to generate cDNAs by using PCR to amplify copies of the region between a single point in the transcript and the 3' or 5' end. Primers oriented in the 3' and 5' directions can be designed from the polynucleic acid molecules of the present invention. Using commercially available 3 'RACE or 5 'RACE systems (Gibco BRL, Life Technologies, Gaithersburg, Maryland U.S.A.), specific 3' or 5' cDNA fragments can be isolated (Ohara et al., Proc. Natl. Acad. Sci. USA 86:5673,1989; Loh et al., Science 243:217, 1989). Products generated by the 3' and 5' RACE procedures can be combined to generate full-length cDNAs (Frohman and Martin, Techniques 1:165, 1989). Polynucleic acid molecules of interest may also be synthesized, either completely or in part, especially where it is desirable to provide modifications in the polynucleotide sequences, by well-known techniques as described in the technical literature, see, e.g., Carruthers et al., Cold Spring Harbor Symp. Quant. Biol. 47:411-418 (1982), and Adams et al., J. Am. Chem. Soc. 105:661 (1983). Thus, all or a portion of the polynucleic acid molecules of the present invention may be synthesized using a codon usage table of a selected plant host. Other modifications of the coding gene sequences may result in mutants having slightly altered activity. All or a substantial portion of the polynucleic acid molecules of the present invention may also be used as probes for genetically and physically mapping the genes that they are a part of, and as markers for traits linked to those genes. Such information may be useful in plant breeding in order to develop lines with desired pheno types. For example, the polynucleic acid molecules of the present invention may be used as restriction fragment length polymorphism (RFLP) markers. Southern blots (Sambrook et al., 1989) of restriction-digested plant genomic DNA may be probed with the polynucleic acid fragments of the present invention. The resulting banding patterns may then be subjected to genetic analyses using computer programs such as MapMaker (Lander et al., Genomics 1:174-181, 1987), in order to construct a genetic map. In addition, the polynucleic acid fragments of the present invention may be used to probe Southern blots containing restriction endonuclease-treated genomic DNAs of a set of individuals representing parent and progeny of a defined genetic cross. Segregation of the DNA polymorphisms is noted and used to calculate the position of the polynucleotide sequence of the present invention in the genetic map previously obtained using this population (Botstein et al., Am. J. Hum. Genet. 32:314-331, 1980). The production and use of plant gene-derived probes for use in genetic mapping is described in Bernatzky and Tanksley (Plant Mol. Biol. Reporter 4:37-41, 1986). Numerous publications describe genetic mapping of specific cDNA clones using the methodology outlined above or variations thereof. For example, F2 intercross populations, backcross populations, randomly mated populations, near isogenic lines, exotic germplasms, and other sets of individuals may be used for mapping. Such methodologies are well known to those skilled in the art. Polynucleic acid probes derived from the polynucleic acid molecules of the present invention may also be used for physical mapping (i.e., placement of sequences on physical maps; see Hoheisel et al., In: Non-mammalian Genomic Analysis: A Practical Guide, Academic press 1996, pp. 319-346). In another embodiment, polynucleic acid probes derived from the polynucleic acid molecules of the present invention may be used in direct fluorescence in situ hybridization (FISH) mapping (Trask, Trends Genet. 7:149-154, 1991). Although current methods of FISH mapping favor use of large clones (several to several hundred kilobases; see Laan et al., Genome Res. 5:13-20, 1995), improvements in sensitivity may allow performance of FISH mapping using shorter probes. A variety of polynucleic acid amplification-based methods of genetic and physical mapping may be carried out using the nucleotide molecules of the present invention. Examples include allele-specific amplification (Kazazian et al., J. Lab. Clin. Med. 11:95-96, 1989), polymorphism of PCR-amplified fragments (CAPS; Sheffield et al., Genomics 16:325-332, 1993), allele-specific ligation (Landegren et al., Science 241:1077-1080, 1988), nucleotide extension reactions (Sokolov et al., Nucleic Acid Res. 18:3671, 1990), Radiation Hybrid Mapping (Walter et al., Nat. Genet. 7:22-28, 1997) and Happy Mapping (Dear and Cook, Nucleic Acid Res. 17:6795-6807, 1989). For these methods, the sequence of a polynucleic acid fragment is used to design and produce primer pairs for use in the amplification reaction or in primer extension reactions. The design of such primers is well known to those skilled in the art. In methods employing PCR-based genetic mapping, it may be necessary to identify DNA sequence differences between the parents of the mapping cross in the region corresponding to the nucleotide sequence. This, however, is generally not necessary for mapping methods. Isolated polynucleic acid molecules of the present invention may find use in the identification of loss of function mutant phenotypes of a plant, due to a mutation in one or more endogenous genes encoding polypeptides of the present invention. This can be accomplished either by using targeted gene disruption protocols or by identifying specific mutants for these genes contained in a population of plants carrying mutations in all possible genes (Ballinger and Benzer, Proc. Natl. Acad Sci USA 86:9402-9406, 1989; Koes et al., Proc. Natl. Acad. Sci. USA 92:8149-8153, 1995; Bensen et al., Plant Cell 7:75-84, 1995; all of which are incorporated herein by reference in their entirety). The latter approach may be accomplished in two ways. First, short segments of the polynucleic acid molecules of the present invention may be used in polymerase chain reaction protocols in conjunction with a mutation tag sequence primer on DNAs prepared from a population of plants in which mutator transposons or some other mutation-causing DNA element has been introduced. The amplification of a specific DNA fragment with these primers indicates the insertion of the mutation tag element in or near the plant gene encoding polypeptides. Alternatively, the polynucleic acid molecules of the present invention may be used as a hybridization probe against PCR amplification products generated from the mutation population using the mutation tag sequence primer in conjunction with an arbitrary genomic site primer, such as that for a restriction enzyme site-anchored synthetic adapter. The polypeptides of the present invention may also include fusion polypeptides. A polypeptide that comprises one or more additional polypeptide regions not derived from that polypeptide is a "fusion" polypeptide. Such molecules may be derivatized to contain carbohydrate or other moieties (such as keyhole, limpet, hemocyanin, etc.). Fusion polypeptides of the present invention are preferably produced via recombinant means. The polypeptide molecules of the present invention may also include polypeptides encoded by all or a substantial portion of polypeptide-encoding sequences set forth in SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16 and SEQ ID NO: 18 or complements thereof or, fragments or fusions thereof in which conservative, non-essential, or not relevant, amino acid residues have been added, replaced, or deleted. An example of such a homologue is the homologue polypeptide (or protein) from different species. Such a homologue can be obtained by any of a variety of methods. For example, as indicated above, one or more of the disclosed sequences, all or a substantial portion of a polypeptide-encoding sequences selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16 and SEQ ID NO: 18; and complements thereof will be used to define a pair of primers that may be used to isolate the homologue-encoding polynucleic acid molecules from any desired species. Such molecules can be expressed to yield homologues by recombinant means. Polynucleic acid molecules that encode all or part of the polypeptides of the present invention can be expressed, via recombinant means, to yield polypeptides that can in turn be used to elicit antibodies that are capable of binding the expressed polypeptides. It may be desirable to derivatize the obtained antibodies, for example with a ligand group (such as biotin) or a detectable marker group (such as a fluorescent group, a radioisotope or an enzyme). Such antibodies may be used in immunoassays for that polypeptide. In a preferred embodiment, such antibodies can be used to screen cDNA expression libraries to isolate full-length cDNA clones of the present invention (Lemer, Adv. Immunol. 36:1, 1984; Sambrook et al., 1989). The isolated polynucleic acid molecules of the present invention can find particular use in creating transgenic plants in which polypeptides of the present invention are overexpressed. Overexpression of these polypeptides in a plant can enhance plant stress tolerance and thereby lead to improvement in the yield of the plant. It will be particularly desirable to enhance plant drought and osmotic stress tolerance in crop plants that undergo such stresses over the course of a normal growing season. The term "transgenic plant" means a plant that contains an exogenous polynucleic acid, which can be derived from the same plant species or from a different species. By "exogenous" it is meant that a polynucleic acid molecule originates from outside the plant that the polynucleic acid molecule is introduced. An exogenous polynucleic acid molecule can have a naturally occurring or non-naturally occurring nucleotide sequence. One skilled in the art understands that an exogenous polynucleic acid molecule can be a heterologous polynucleic acid molecule derived from a different plant species than the plant into which the polynucleic acid molecule is introduced or can be a polynucleic acid molecule derived from the same plant species as the plant into which it is introduced. Crop plant cell, as used herein, includes without limitation, seeds, suspension cultures, embryos, meristematic regions, callus tissue, leaves, roots, shoots, gametophytes, sporophytes, pollen and microspores. The term "genome" as it applies to plant cells encompasses not only chromosomal DNA found within the nucleus, but organelle DNA found within subcellular components of the cell. DNAs of the present invention introduced into plant cells can therefore be either chromosomally integrated or organelle-localized. The term "genome" as it applies to bacteria encompasses both the chromosome and plasmids within a bacterial host cell. Encoding DNAs of the present invention introduced into bacterial host cells can therefore be either chromosomally integrated or plasmid-localized. Exogenous polynucleic acid molecules may be transferred into a crop plant cell by the use of a recombinant DNA construct (or vector) designed for such a purpose. The present invention also provides a plant recombinant DNA construct (or vector) for producing transgenic plants; wherein the plant recombinant DNA construct (or vector) comprises a structural nucleotide sequence encoding an polypeptide of the present invention. Methods that are well known to those skilled in the art may be used to prepare the crop plant recombinant DNA construct (or vector) of the present invention. These methods include in vitro recombinant DNA techniques, synthetic techniques, and in vivo genetic recombination. Such techniques are described in Sambrook et al., (1989). A plant recombinant DNA construct (or vector) of the present invention contains a structural nucleotide sequence encoding a polypeptide of the present invention and operably linked to regulatory sequences. Exemplary regulatory sequences include but are not limited to promoters, translation leader sequences, introns and 3' non-translated sequences. The promoters can be constitutive, inducible, native, or tissue-specific promoters. DNA constructs used for transforming plants to practice current invention comprises any promoter known to function to cause the transcription in plant cells and any antibiotic or herbicide tolerance encoding polynucleotide sequence known to confer antibiotic or herbicide tolerance to plant cells. The antibiotic tolerance polynucleotide sequences include, but are not limited to polynucleotide sequences encoding for proteins involved in tolerance to kanamycin, neomycin, hygromycin, and other antibiotics known in the art. Antibiotic tolerance gene in such a vector can be replaced by herbicide tolerance encoding for 5- enolpyruvylshikimate-3-phosphate synthase (EPSPS, described in U.S. Patent Nos. 5,627,061, and 5,633,435, herein incorporated by reference in its entirety; Padgette et al. (1996) Herbicide Resistant Crops, Lewis Publishers, 53-85, and in Penaloza-Vazquez, et al. (1995) Plant Cell Reports 14:482-487) and aroA (U.S. Patent Number 5,094,945) for glyphosate tolerance, bromoxynil nitrilase (Bxn) for Bromoxynil tolerance (U.S. Patent No. 4,810,648), phytoene desaturase (crtl (Misawa et al, (1993) Plant Journal 4:833-840, and (1994) Plant Jour 6:481-489) for tolerance to norflurazon, acetohydroxyacid synthase (AHAS, Sathasiivan et al. (1990) Nucl. Acids Res. 18:2188-2193) and the bar gene for tolerance to glufosinate (DeBlock, et al. (1987) EMBO J. 6:2513-2519. Herbicides for which transgenic plant tolerance has been demonstrated and the method of the present invention can be applied include, but are not limited to: glyphosate, glufosinate, sulfonylureas, imidazolinones, bromoxynil, delapon, cyclohezanedione, protoporphyrionogen oxidase inhibitors, and isoxaslutole herbicides. Genetic elements of transgene DNA constructs used for plant transformation and expression of transgenes in plants include, but are not limited to: plant virus promoters, e.g., P-CaMV.35S promoter (U.S. Patent No. 5,858,742, herein incorporated by reference in its entirety), the CaMV 35S promoter with a duplicated enhancer (U.S. Patent No.5,539,142, herein incorporated by reference in its entirety), the Figwort mosaic virus promoter, P-FMV, as described in U. S. Patent No. 5,378,619, herein incorporated by reference in its entirety; or the P-AtEFla (P-AtEFl or EFla), the sugarcane bacilliform virus promoter, commelina yellow mottle virus or other Badnavirus promoters; heterologous plant promoters, e.g., plant actin promoters including the rice actin 1 promoter and intron (U.S. Patent No. 5,641,876) and rice actin 2 promoter and intron (U.S. Patent No. 6,429,357), Arabidopsis actin promoters, a promoter region from the tomato elongation factor gene and Arabidopsis thaliana elongation factor gene la; the Gbo lO and Gboxl 1 motif (Fumiharu et al., Plant J. 18:443-448, 1999); or the DC3 promoter region from carrot (Seffens et al., Develop. Genet. 11:65-76); or the TP12 promoter (GenBank accession no. U68483). The genetic elements of the DNA construct further comprise 5' leader polynucleotides for example, the Hsp70 non-translated leader sequence from Petunia hybrida as described in U. S. Patent No. 5,362,865, herein incorporated by reference in its entirety. The genetic elements further comprise herbicide tolerance genes that include, but are not limited to, for example, the aroA:CP4 coding region for EPSPS glyphosate resistant enzyme isolated from Agrobacterium tumefaciens (AGRTU) strain CP4 as described in U. S. Patent No. 5,633,435, herein incorporated by reference in its entirety.

The genetic elements of the DNA construct further comprise 3' termination regions that include, but are not limited to, the E9 3' termination region of the pea RbcS gene that functions as a polyadenylation signal; the nos3' is the 3' end of the Ti plasmid nopaline synthase gene that functions as a polyadenylation signal ; or the TML is 3' the end of the Ti plasmid octopine pTil5955 synthase gene (GenBank Accession AF 242881) that functions as a polyadenylation signal . The genetic elements of the DNA construct further comprise the right border (RB) and left borders (LB) of the Ti plasmid of Agrobacterium tumefaciens octopine and nopaline strains. A plant recombinant DNA construct (vector) of the present invention will typically comprise a selectable marker that confers a selectable phenotype on plant cells. Selectable markers may also be used to select for plants or plant cells that contain the exogenous polynucleic acid molecules encoding polypeptides of the present invention. The marker may encode biocide resistance, antibiotic resistance (e.g, kanamycin, G418, bleomycin, hygromycin, etc.), or herbicide resistance (e.g., glyphosate, glufosinate, etc.). Examples of selectable markers include, but are not limited to, a neo gene (Potrykus et al., Mol. Gen. Genet. 199:183-188 (1985) that codes for kanamycin resistance and can be selected for using kanamycin, G418, etc.; a bar gene that codes for bialaphos resistance; a mutant EPSP synthase gene (Hinchee et al., Bio/Technology 6:915-922 (1988) that encodes glyphosate resistance; a nitrilase gene that confers resistance to bromoxynil (Stalker et al., J. Biol. Chem. 263:6310-6314 (1988); a mutant acetolactate synthase gene (ALS) that confers imidazolinone or sulphonylurea resistance, and a methotrexate resistant DHFR gene (Thillet et al., J. Biol. Chem. 263:12500-12508 (1988). A plant recombinant DNA construct (vector) of the present invention may also include a screenable marker. Screenable markers may be used to monitor expression. Exemplary screenable markers include a β-glucuronidase or uidA gene (GUS:1) that encodes an enzyme for that various chromogenic substrates are known (Jefferson, Plant Mol. Biol, Rep. 5:387-405 (1987); Jefferson et al., EMBO J. 6:3901-3907 (1987); an R-locus gene, that encodes a product that regulates the production of anthocyanin pigments (red color) in plant tissues (Dellaporta et al., Stadler Symposium 11:263-282 (1988); a β-lactamase gene (Sutcliffe et al., Proc. Natl. Acad. Sci. (U.S.A.) 75:3737-3741 (1978), a gene that encodes an enzyme for that various chromogenic substrates are known (e.g., PAD AC, a chromogenic cephalosporin); a luciferase gene (Ow et al., Science 234:856-859 (1986) a xylE gene (Zukowsky et al., Proc. Natl. Acad. Sci. (U.S.A.) 80:1101-1105 (1983) that encodes a catechol dioxygenase that can convert chromogenic catechols; an α-amylase gene (Ikatu et al., Bio/Technol. 8:241-242 (1990); a tyrosinase gene (Katz et al., J. Gen. Microbiol. 129:2703-2714 (1983) that encodes an enzyme capable of oxidizing tyrosine to DOPA and dopaquinone that in turn condenses to melanin; an - galactosidase, that will turn a chromogenic α-galactose substrate. Included within the terms "selectable or screenable marker genes" are also genes that encode a secretable marker whose secretion can be detected as a means of identifying or selecting for transformed cells. Examples include markers that encode a secretable antigen that can be identified by antibody interaction, or even secretable enzymes that can be detected catalytically. Secretable proteins fall into a number of classes, including small, diffusible proteins detectable, e.g., by ELISA, small active enzymes detectable in extracellular solution (e.g., α-amylase, β-lactamase, phosphinothricin transferase), or proteins that are inserted or trapped in the cell wall (such as proteins that include a leader sequence such as that found in the expression unit of extension or tobacco PR-S). Other possible selectable and/or screenable marker genes will be apparent to those of skill in the art. In addition to a selectable marker, it may be desirable to use a reporter gene. In some instances a reporter gene may be used with or without a selectable marker. Reporter genes are genes that are typically not present in the recipient organism or tissue and typically encode for proteins resulting in some phenotypic change or enzymatic property. Examples of such genes are provided in K. Wising et al. Ann. Rev. Genetics, 22, 421 (1988), that is incorporated herein by reference. Preferred reporter genes include the beta-glucuronidase (GUS) of the uidA locus of E. coli, the chloramphenicol acetyl transferase gene from Tn9 of E. coli, the green fluorescent protein from the bioluminescent jellyfish Aequorea victoria, and the luciferase genes from firefly Photinus pyralis. An assay for detecting reporter gene expression may then be performed at a suitable time after said gene has been introduced into recipient cells. A preferred such assay entails the use of the gene encoding beta-glucuronidase (GUS) of the uidA locus of E. coli as described by Jefferson et al., (Biochem. Soc. Trans. 15, 17-19 (1987) to identify transformed cells, referred to herein as GUS: 1. In preparing the recombinant DNA constructs (vectors) of the present invention, the various components of the construct or fragments thereof will normally be inserted into a convenient cloning vector, e.g., a plasmid that is capable of replication in a bacterial host, e.g., E. coli. Numerous cloning vectors exist that have been described in the literature, many of that are commercially available. After each cloning, the cloning vector with the desired insert may be isolated and subjected to further manipulation, such as restriction digestion, insertion of new fragments or nucleotides, ligation, deletion, mutation, resection, etc. so as to tailor the components of the desired sequence. Once the construct has been completed, it may then be transferred to an appropriate vector for further manipulation in accordance with the manner of transformation of the host cell. Transforming desired constructs capable of expressing polypeptide of the present invention can produce transgenic plants. Transgenic corn can be produced by particle bombardment transformation methods as described in U.S. Patent No. 5,424,412. The vector DNA are digested with suitable restriction endonucleases to isolate a plant expression cassette that expresses the polypeptides of the present invention in the plant. The desired expression cassette is purified by agarose gel electrophoresis, then bombarded into embryogenic corn tissue culture cells using a Biolistic® (Dupont, Wilmington, DE) particle gun with purified isolated DNA fragment. Transformed cells are selected by challenging transformed cells by selection media. One such example of such a selection where aroA:CP4 gene is part of expression cassette could be glyphosate (N-phosphonomethyl glycine and its salts) containing media, which is used for growing transformed plant cells. Whole plants are regenerated then grown under greenhouse conditions. Fertile seed is collected, planted and screened for selectable marker; for example plant expressing desired polypeptide of the invention along with aroA:CP4 gene product can be screened by spraying glyphosate to select glyphosate tolerant plant. Pant expressing desired polypeptide of the invention is then back crossed into commercially acceptable corn germplasm by methods known in the art of corn breeding (Sprague et al., Corn and Corn Improvement 3^rd Edition, Am. Soc. Agron. Publ (1988). Transgenic corn plants can also be produced by an Agrobacterium mediated transformation method. A disarmed Agrobacterium strain C58 (ABI) harboring a DNA construct can be used for all the experiments. The construct is transferred into Agrobacterium by a triparental mating method (Ditta et al., Proc. Natl. Acad. Sci. 77:7347-7351). Liquid cultures of Agrobacterium are initiated from glycerol stocks or from a freshly streaked plate and grown overnight at 26°C-28°C with shaking (approximately 150 rpm) to mid-log growth phase in liquid LB medium, pH 7.0 containing 50 mg/1 kanamycin, 50 mg/1 streptomycin and spectinomycin and 25 mg/1 chloramphenicol with 200 μM acetosyringone (AS). The Agrobacterium cells are resuspended in the inoculation medium (liquid CM4C) and the density is adjusted to OD₆₆o of 1. Freshly isolated Type JJ immature HiIIxLH198 and Hill corn embryos are inoculated with Agrobacterium containing a DNA construct of the present invention and co-cultured 2-3 days in the dark at 23 °C. The embryos are then transferred to delay media (N6 1-100-12/micro/Carb 500/20 μM AgN03) and incubated at 28 °C for 4 to 5 days. All subsequent cultures are kept at this temperature. Coleoptiles are removed one week after inoculation. The embryos are transferred to the first selection medium (N61-0-12/Carb 500/0.5 mM glyphosate). Two weeks later, surviving tissues are transferred to the second selection medium (N61-0-12/Carb 500/1.0 mM glyphosate). Subculture surviving callus every 2 weeks until events can be identified. This will take 3 subcultures on 1.0 mM glyphosate. Once events are identified, bulk up the tissue to regenerate. For regeneration, callus tissues are transferred to the regeneration medium (MSOD, 0.1 μM ABA) and incubated for two weeks. The regenerating calli are transferred to a high sucrose medium and incubated for two weeks. The plantlets are transferred to MSOD media in culture vessel and kept for two weeks. Then the plants with roots are transferred into soil. Soybean transformation is performed essentially as described in WO 00/42207, herein incorporated by reference in its entirety. The present invention also provides a transgenic plant comprising in its genome a polynucleic acid that comprises: (A) a 5' non-coding sequence that functions in the cell to cause the production of a mRNA molecule; that is operably linked to (B) a structural poly nucleotide sequence encoding a polypeptide of this invention that is operably linked to (C) a 3' non-translated sequence that functions in said cell to cause termination of transcription. Preferably, the amino acid sequence of the polypeptide has at least 75% sequence identity, about 80% sequence identity, or about 85% or about 90% sequence identity to a member selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16 and SEQ ID NO: 18. The polypeptide can also have one of the sequences set forth in SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16 and SEQ ID NO: 18 with or without conservative amino acid substitutions. Transgenic plants of the present invention have incorporated into their genome, or transformed into their chloroplast or plastid genomes, an exogenous polynucleic acid molecule that comprises at least a structural nucleotide sequence that encodes a polypeptide having an amino acid sequence selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16 and SEQ ID NO: 18. Transgenic plants are also meant to comprise progeny (descendant, offspring, etc.) of any generation of such a transgenic plant. A seed of any generation of all such transgenic plants wherein said seed comprises a DNA sequence encoding the polypeptide of the present invention is also an important aspect of the invention. Hybrid seeds are also envisioned as being within the scope of the present invention and such hybrid seeds containing a structural nucleotide sequence of the present invention may be produced by techniques known in the art. The present invention also provides a method of screening transformed plants for the presence of transformed nucleic acids of the invention or polypeptides expressed by the nucleic acid of the invention conferring desired agronomic traits. The nature of these screens will generally be chosen on practical grounds. For example, one can screen by looking for changes in gene expression by using antibodies specific for the polypeptide encoded by the gene being suppressed. Alternatively, one could establish assays that specifically measure enzyme activity. A preferred method will be one that allows large numbers of samples to be processed rapidly, since it will be expected that a large number of transformants will be negative for the desired phenotype. In one embodiment, the transgenic plants of the present invention will have a higher rate of photosynthesis, measured as the rate of carbon assimilation due to the expression of an exogenous polynucleic acid molecule encoding a polypeptide of the present invention. The transgenic plants of present invention will have higher rate of photosynthesis when compared to natural plants of same species. Natural plants of same species will be without exogenous polynucleic acid molecules encoding polypeptide of the present invention. In another embodiment, the transgenic plants of the present invention will have higher carbon assimilation, measured as an increase in metabolite content due to the expression of an exogenous polynucleic acid molecule encoding a polypeptide of the present invention. Plant metabolites include carbon-based molecules, which are produced or metabolized by plants. In another embodiment, the transgenic plants of present invention will have increased tolerance to environmental stress due to the expression of an exogenous polynucleic acid molecule encoding a polypeptide of the present invention. The transgenic plants of present invention will have tolerance to abiotic stresses for example variations from optimal condition to sub-optimal conditions for water, humidity, temperature, light or other radiations, organic and inorganic nutrients, or salinity. Drought is defined as sub-optimal conditions for water and humidity needed for normal growth of natural plants. The transgenic plants of the present invention will have higher tolerance to drought and a higher yield of agricultural products under drought conditions as compared to natural plants. The DNA construct of the present invention may be introduced into the genome of a desired plant host by a variety of conventional transformation techniques that are well known to those skilled in the art. Methods of transformation of plant cells or tissues include, but are not limited to Agrobacterium mediated transformation method and the Biolistics or particle-gun mediated transformation method. Suitable plant transformation vectors for the purpose of Agrobacterium mediated transformation include those derived from a Ti plasmid of Agrobacterium tumefaciens, as well as those disclosed, e.g., by Herrera-Estrella et al., Nature 303:209 (1983); Bevan, Nucleic Acids Res. 12: 8711-8721 (1984); Klee et al, Bio- Technology 3(7): 637-642 (1985); and EP 120,516. In addition to plant transformation vectors derived from the Ti or root-inducing (Ri) plasmids of Agrobacterium, alternative methods can be used to insert the DNA constructs of this invention into plant cells. Such methods may involve, but are not limited to, for example, the use of liposomes, electroporation, chemicals that increase free DNA uptake, free DNA delivery via microprojectile bombardment, and transformation using viruses or pollen. A plasmid expression vector suitable for the introduction of a polynucleic acid encoding a polypeptide of present invention in monocots using electroporation or particle-gun mediated transformation is composed of the following: a promoter that is constitutive, tissue-specific, tissue enhanced or native; an intron that provides a splice site to facilitate expression of the gene, such as the maize Hsp70 intron (U.S. Patent No. 5,593,874, herein incorporated by reference in its entirety); and a 3' polyadenylation sequence such as the nopaline synthase 3' sequence (nos 3'; Fraley et al., Proc. Natl. Acad. Sci. USA 80: 4803-4807, 1983). This expression cassette may be assembled on high copy replicons suitable for the production of large quantities of DNA. An example of a useful Ti plasmid cassette vector for plant transformation is pMON17227. This vector is described in U.S. Patent 5,633,435, herein incoφorated by reference in its entirety, and contains a gene encoding an EPSPS enzyme with glyphosate resistance (herein referred to as aroA:CP4), that is an excellent selection marker gene for many plants. The gene is fused to the Arabidopsis EPSPS chloroplast transit peptide (At. EPSPS:CTP2) and expressed from the Figwort mosaic virus (P-FMV) promoter as described therein. ^• When adequate numbers of cells containing the exogenous polynucleic acid molecule encoding polypeptides from the present invention are obtained, the cells can be cultured, then regenerated into whole plants. Such regeneration techniques rely on manipulation of certain phytohormones in a tissue culture growth medium, typically relying on a biocide and/or herbicide marker that has been introduced together with the desired nucleotide sequences. -The methodology for the regeneration step is well known in the art in regard of the crop plants (Klee et al., Ann. Rev. Plant Phys. 38:467-486 1987). The development or regeneration of transgenic plants containing the exogenous polynucleic acid molecule that encodes a polypeptide of interest is well known in the art. Preferably, the regenerated plants are self-pollinated to provide homozygous transgenic plants, as discussed above. Otherwise, pollen obtained from the regenerated plants is crossed to seed-grown plants of agronomically important lines. Conversely, pollen from plants of these important lines is used to pollinate regenerated plants. Plants of the present invention include, but are not limited to, Acacia, alfalfa, aneth, apple, apricot, artichoke, arugula, asparagus, avocado, banana, barley, beans, beet, blackberry, blueberry, broccoli, brussels sprouts, cabbage, canola, cantaloupe, carrot, cassava, cauliflower, celery, cherry, cilantro, citrus, Clementines, coffee, corn, cotton, cucumber, Douglas fir, eggplant, endive, escarole, eucalyptus, fennel, figs, forest trees, gourd, grape, grapefruit, honey dew, jicama, kiwifruit, lettuce, leeks, lemon, lime, loblolly pine, mango, melon, mushroom, nut, oat, okra, onion, orange, an ornamental plant, papaya, parsley, pea, peach, peanut, pear, pepper, persimmon, pine, pineapple, plantain, plum, pomegranate, poplar, potato, pumpkin, quince, radiata pine, radicchio, radish, rapeseed, raspberry, rice, rye, sorghum, Southern pine, soybean, spinach, squash, strawberry, sugarbeet, sugarcane, sunflower, sweet potato, sweetgum, tangerine, tea, tobacco, tomato, turf, a vine, watermelon, wheat, yams, and zucchini. Crop plants are defined as plants, which are cultivated to produce one or more commercial product, examples of such crops or crop plants include alfalfa, soybean, canola, rape, cotton (cottonseeds), sunflower, and grains such as corn, wheat, rice, rye, and the like. The following examples are provided to better elucidate the practice of the present invention and should not be interpreted in any way to limit the scope of the present invention. Those skilled in the art will recognize that various modifications, additions, substitutions, truncations, etc., can be made to the methods and genes described herein while not departing from the spirit and scope of the present _" invention.

EXAMPLES

EXAMPLE 1 Stock Plant Material and Growth Conditions Arabidopsis thaliana var Columbia seeds are obtained from Lehle Seeds Co. (LEHLE SEEDS 1102 South Industrial Blvd., Suite D, Round Rock TX 78681 USA). The seeds are sown into 2 inch pots prepared with soil covered with bridal veil or a mesh screen, making sure that the soil is not packed too tightly and the mesh is in contact with the soil surface (this ensures that the germinating seedlings will be able to get through the mesh. Seeds are sown and covered with a germination dome. Seeds are vernalized for 3-4 days. Plants are grown under conditions of 16 hours light / 8 hours dark at 20-22° C, 70% humidity. They are watered twice weekly, and fertilize from below with 1/2 X (half of the strength recommended by the manufacturer) Peters 20-20-20 fertilizer (from Hummert International, Earth City, MO). Micronutrients are added (Hummert' s Dyna-grain Soluble Trace Elements) (in full strength recommended by the manufacturer) every other week. After about 1-2 weeks, dome is removed and pots are thinned to one or two plants per pot. Clip the primary bolt, when it develops, to encourage more secondary bolt formation. EXAMPLE 2

Identification of Homologs. Paralogs or Orthologs For construction of cDNA libraries from plants, plant tissues are harvested and immediately frozen in liquid nitrogen and stored at -80°C until total RNA extraction. Total RNA is purified by using Trizol reagent from Life Technologies (Gibco BRL, Life Technologies, Gaithersburg, Maryland U.S.A.), essentially as recommended by the manufacturer. Poly A+ RNA (mRNA) is purified using magnetic oligo dT beads essentially as recommended by the manufacturer (Dynabeads, Dynal Corporation, Lake Success, New York U.S.A.). Construction of plant cDNA libraries is well known in the art and a number of cloning strategies exist. A number of cDNA library construction kits are commercially available. The Superscript™ Plasmid System for cDNA synthesis and Plasmid Cloning (Gibco BRL, Life Technologies, Gaithersburg, Maryland U.S.A.) is used, following the conditions suggested by the manufacturer. The cDNA libraries are plated on LB agar containing the appropriate antibiotics for selection and incubated at 37° for sufficient time to allow the growth of individual colonies. Single selective media colonies are individually placed in each well of a 96-well microtiter plates containing LB liquid including the selective antibiotics. The plates are incubated overnight at approximately 37°C with gentle shaking to promote growth of the cultures. The plasmid DNA is isolated from each clone using Qiaprep plasmid isolation kits, using the conditions recommended by the manufacturer (Qiagen Inc., Santa Clara, California U.S.A.). The template plasmid DNA clones are used for subsequent sequencing. For sequencing the cDNA libraries, a commercially available sequencing kit, such as the ABI PRISM dRhodamine Terminator Cycle Sequencing Ready Reaction Kit with AmpliTaq® DNA Polymerase, FS, is used under the conditions recommended by the manufacturer (PE Applied Biosystems, Foster City, CA). The cDNAs of the present invention are generated by sequencing initiated from the 5' end or 3' end of each cDNA clone. Entire inserts or only part of the inserts (ESTs or expressed sequenced tags) are sequenced. A number of DNA sequencing techniques are known in the art, including fluorescence-based sequencing methodologies. These methods have the detection, automation and instrumentation capability necessary for the analysis of large volumes of sequence data. Currently, the 377 and 3700 DNA Sequencer (Perkin-Elmer Corp., Applied Biosystems Div., Foster City, CA) allows the most rapid electrophoresis and data collection. With these types of automated systems, fluorescent dye-labeled sequence reaction products are detected and data entered directly into the computer, producing a chromatogram that is subsequently viewed, stored, and analyzed using the corresponding software programs. These methods are known to those of skill in the art and have been described and reviewed (Birren et al., Genome Analysis: Analyzing DNA,1, Cold Spring Harbor, New York). The generated ESTs (including any full-length cDNA inserts or complete coding sequences) are combined with ESTs and full-length cDNA sequences in public databases such as GenBank. Duplicate sequences are removed, and duplicate sequence identification numbers are replaced. The combined dataset is then clustered and assembled using Pangea Systems (Double Twist, 2001 Broadway, Oakland, CA 94612) tool identified as CAT v.3.2. First, the EST sequences are screened and filtered, e.g. high frequency words are masked to prevent spurious clustering; sequence common to known contaminants such as cloning bacteria are masked; high frequency repeated sequences and simple sequences are masked; unmasked sequences of less than 100 base pairs are eliminated. The thus-screened and filtered ESTs are combined and subjected to a word-based clustering algorithm that calculates sequence pair distances based on word frequencies and uses a single linkage method to group like sequences into clusters of more than one sequence, as appropriate. Clustered sequences are assembled individually using an iterative method based on PHRAP/CRAW/MAP providing one or more self-consistent consensus sequences and inconsistent singleton sequences. The assembled clustered sequence files are checked for completeness and parsed to create data representing each consensus contiguous sequence (contig), the initial EST sequences, and the relative position of each EST in a respective contig. The sequence of the 5' most clone is identified from each contig. The initial sequences that are not included in a contig are separated out. Above described databases with nucleotide and peptide sequences are queried with sequences of present invention to get following homologues, orthologs or paralogs as shown in Table 1. The BLAST 2.2.1 software (Altschul, et.al., Nucleic Acids Res. 25: 3389-3402 (1997), with BLOSUM62 matrix and "no Filter" options, is used in the queries. As when necessary, frame-shifts in the DNA sequences of the homologues are detected by aligning the DNA sequence of the homologue in question to the protein sequence of present invention, using the "frame+_n2p" program with default parameters in the GenCore software package (Compugen Inc., 25 Leek Crescent , Richmond Hill, Ontario, L4B 4B3, Canada, 1998). Such frame-shifts are conceptually corrected to yield open reading frames. The "translate" program with default parameters in the same package is used to translate open reading frames to corresponding peptide sequences based on standard genetic codes. TABLE 1. Description of homologs, orthologs or paralogs of SEQ ID NO: 1

EXAMPLE 3

Isolation of polynucleotide molecules of the present invention and their modification For isolating polynucleotide molecules of the present invention, total RNA is isolated from appropriate crop and other desired plant species by pooling tissues of different developmental stages of all vegetative and reproductive organs. RNA is prepared from pooled plant tissue by the Trizol method (Gibco BRL, Life Technologies, Gaithersburg, Maryland U.S.A.) essentially as recommended by the manufacturer. Sequences are amplified out from total RNA by using Superscript TJ kit (Gibco BRL, Life Technologies, Gaithersburg, Maryland U.S.A.) according to the manufacturer's directions. Design of appropriate PCR primers for isolating sequences of present invention is based on the sequence information provided in the sequence listing of this disclosure. Design of primers and reaction conditions are determined as described in the art. (PCR Strategies, Edited by Michael A. Innis; David H. Gelfand; & Johm J. Sninsky; Academic Press 1995 and PCR Protocols, A Guide to Method and Applications, Edited by Michael A. Innis; David H. Gelfand; Johm J. Sninsky; & Thomas J. White Academic Press 1990). All reagents for isolating sequences of the invention can be procured form Gibco BRL, Life Technologies, Gaithersburg, Maryland U.S.A.

EXAMPLE 4 This example describes different plant expression vectors for transforming plant to obtain plants of present inventions. DNA constructs and corresponding backbones are provided as figure as per the following table: TABLE 2

The expression cassette used for transforming plants to practice the current invention comprises any one of the known promoter to function to cause the transcription of desired gene in plant cells and any one of the known antibiotic or herbicide tolerance encoding polynucleotide sequence known to confer antibiotic or herbicide tolerance to plant cells. It is essential that components of expression cassette in a DNA constructs (expression vector) of the invention are operabily linked with each other in a specific order to cause the expression of desired gene product in a plant for generating transgenic plants of the invention. Specific order of operably linked essential components of each expression vectors are shown in figures 2, 4, 6, 8, 10, 12, 14, 16, 17, 19 and 20. Usually expression cassette are flanked by right and left borders denoted as RB and LB respectively in accompanying figures 2, 4, 6, 8, 10, 12, 14, 16, 17, 19 and 20. Every component of expression cassette and DNA construct is described in a prior section of this application (detailed description). Expression cassette is assembled in a circular DNA construct in order to generate, isolated desired amounts of DNA in E. coli and is known as vector backbone. Many vector backbones are well known in the art, one of such vector backbone is pBR 322 which can be used for generation of DNA constructs for practicing the invention. The DNA constructs are double border plant transformation constructs that also contain DNA segments that provide replication function and antibiotic selection in bacterial cells, for example, an E. coli origin of replication such as ori322, a broad host range origin of replication such as oriV or oriRi, and a coding region for a selectable marker such as Spc/Str that encodes for Tn7 aminoglycoside adenyltransferase (aadA) conferring resistance to spectinomycin or streptomycin, or a gentamicin (Gm, Gent) selectable marker gene. For plant transformation, the host bacterial strain is Agrobacterium tumefaciens ABI or LBA4404. The polylinker regions in these DNA construct provide for multiple restriction endonuclease cut sites that digest the DNA to provide a cloning site in order to clone genes of present in invention in expression cassette. Examples of such cloning sites may include Bglll, Ncol, EcoRI, Sail, Notl, Xhol and other sites known to those skilled in the art of molecular biology. In addition to above elements construct may also include an epitope tag ( For example Flag® peptide catalog number F-3290, SIGMA, P.O. Box 14508 St. Louis, MO 63178 USA) at the 3' termination region of gene of interest (Figures A, B, C). The GATEWAY™ cloning technology (Invitrogen Life Technologies, Carlsbad, California) is also used for construction of few vectors of the invention (Figures C, D, E). GATEWAY™ technology uses phage lambda base site-specific recombination for vector construction, instead of restriction endonucleases and ligases. The GATEWAY™ method produces a high frequency of inserts in a plasmid in the correct orientation relative to other elements in the plasmid such as promoters, enhancers, and the such. Routine cloning of any desired DNA sequence into a vector comprising operable plant expression elements is thereby facilitated. Using the GATEWAY™ cloning technology, a desired DNA sequence, such as a coding sequence, may be amplified by PCR with the phage lambda αttBl sequence added to the 5' primer and the αttB2 sequence added to the 3' primer. Alternatively, nested primers comprising a set of αttBl and αttB2 specific primers and a second set of primers specific for the selected DNA sequence can be used. Sequences, such as coding sequences, flanked by αttBl and αttB2 sequences can be readily inserted into plant expression vectors using GATEWAY™ methods. Assembly of DNA constructs are done by standard molecular biology techniques as described in Sambrooks et al. EXAMPLE 5 Arabidopsis plant transformation with construct expressing gene of present invention Arabidopsis plants are transformed by any one of many available methods. For example, Arabidopsis plants may be transformed using In planta transformation method by vacuum infiltration (see, Bechtold et al., In planta Agrobacterium mediated gene transfer by infiltration of adult Arabidopsis thaliana plants. CR Acad. Sci. Paris Sciences de la vie/life sciences 316: 1194-1199 (1993). Plants are grown as described in Examplel. Seeds recovered from plants transformed with construct were germinated and selected on media containing antibiotic kanamycin. Surviving plants were assayed by TaqMan assay for the copy number of the insert. Several individual lines were selected that had single copy plant expression cassettes and were designated as PLANT -1, PLANT -2, PLANT -3, and PLANT -4. EXAMPLE 6 This example describes how photosynthesis was measured in plants. Rate of photosynthesis was measured as by measuring rate of carbon assimilation as reflected by carbon dioxide gas exchange under different concentrations of C0₂. For measuring carbon dioxide (C0₂) gas exchange, Li-6400 Portable Photosynthesis System (Li-Cor Bioscience, Lincoln, Nebraska) was used as per manufacturer's instruction. Measurement was done under varying C0₂ concentration and at light intensity of 150 μE M^"2 S^"1, as shown in the Table 3. Carbon assimilation rates were measured as C02 gas exchange from Arabidopsis plants over expressing the CCA-1 gene by using the e35S promoter. C0₂ exchange was expressed as micromole. per square meter leaf area per second (μmol/m²/s). When plants expressing CCA-1 polypeptide, such as line PLANT-1 were compared with plants without any gene and when carbon assimilation rates were measured as a function of C0₂ concentration in the LiCOR chamber, assimilation rates were significantly higher in PLANT- 1, above a C02 concentration of 600 ppm as shown in Table 3. These results demonstrate that plants over expressing the gene of the present invention provide enhanced assimilation of carbon under varying concentrations of C0_2ι leading to increased photosynthetic potential in plants of the present invention expressing CCAl polypeptide molecules. TABLE 3 A & B. Carbon assimilation rates of wild-type (A) and PLANT- 1 (B) plants as a function of C02 concentration. TABLE 3 A. Wild type

TABLE 3 B. PLANT-1

EXAMPLE 7 This example describes how plants of the present invention grown under different light conditions can assimilate different amounts of carbon as reflected by carbon dioxide gas exchange. C0₂ exchange was measured as indicated in example 6. C0₂ gas exchange measurements indicated that CCAl over expression also increases the photosynthetic efficiency of plants grown under low light. Wild type and PLANT- 1 plants were grown for 21 days under 150 micro Einstein/m Is. Half the plants were transferred to a chamber covered with cloth to reduce the light intensity to 65 micro Einstein/m2/s. The remaining plants were allowed to continued growth under 150 micro Einstein/m²/s. After 20 days, the plants were measured for carbon assimilation using a LiCOR 6400 photosynthesis system where carbon assimilation was measured as a function of light intensity in the LiCOR chamber and where the C0 concentration within the chamber was held at 350 ppm. Wild type and PLANT- 1 plants grown continuously at 150 micro Einstein/m²/s showed no difference in carbon assimilation. However, PLANT- 1 plants grown under 65 micro Einstein/m²/s showed significantly higher carbon assimilation compared to wild-type plants grown under identical conditions (Table 4). The results demonstrate that PLANT- 1 plants grown under low light adapt more efficiently to low light conditions in terms of photosynthetic efficiency.

TABLE 4. Carbon assimilation rates of wild type and PLANT- 1 plants grown under normal (A) and low light (B) conditions.

TABLE 4 A: Normal light grown.

Light Intensity C02 Assimilation (micromol/m²/s)

(micro Einstein/m2/s) Wild tvne PLANT-1

0 -1.29 4-/- 0.20 -1.724-/- 0.08

35 0.48 4-/- 0.14 0.31 4-/- 0.03

70 2.46 4-/- 0.15 1.98 4-/- 0.16

100 3.63 4-/- 0.31 3.36 4-/- 0.27

200 5.96 4-/- 0.13 6.31 4-/- 0.4

400 6.744-/- 0.26 7.33 4-/- 0.69

800 6.95 +/- 0.26 7.56 4-/- 0.69

1200 7.29 4-/- 0.29 8.07 4-/- 0.8 TABLE 4 B: Low light grown.

Light Intensity CO? Assimilation (micromol/m²/s)

(micro Emstein/m2/s) Wild-tvϋe PLANT-1

0 -1.52 +/- 0.17 -1.41 +1- 0.16

35 0.48 4-/- 0.16 0.62 +1- 0.06

70 1.13 4-/- 0.28 1.81 +1- 0.45

100 1.82 4-/- 0.20 3.09 4-/- 0.31

200 2.18 4-/- 0.17 ^' 3.77 +/- 0.59

400 2.50 4-/- 0.23 4.35 4-/- 0.55

800 2.88 4-/- 0.23 4.90 +/- 0.52

1200 3.07 4-/- 0.20 5.53 4-/- 0.47

EXAMPLE 8

This example describes how plants of the present invention grown under different light conditions can assimilate different amounts of carbon, measured as C0₂ gas exchange. C0₂ gas exchange measurements indicated that CCAl over expression also increases the photosynthetic efficiency of plants grown under low light. Wild type and PLANT-1 plants were grown for 21 days under 150 micro Einstein/m²/s of light intensity. Half the plants were transferred to a chamber covered with cloth to reduce the light intensity to 65 micro Einstein/m²/s. The remaining plants were allowed to continued growth under 150 micro Einstein/m²/s. After 20 days, the plants were measured for carbon assimilation using a LiCOR 6400 photosynthesis system where carbon assimilation was measured as a function of light intensity in the LiCOR chamber and where the C0₂ concentration within the chamber was held at 350 ppm. Wild-type and PLANT-1 plants grown continuously at 150 micro Einstein/m²/s showed no difference in carbon assimilation. However, PLANT-1 plants grown under 65 micro Einstein/m²/s showed significantly higher carbon assimilation compared to wild-type plants grown under identical conditions (Table 5). The results demonstrate that PLANT-1 plants grown under low light adapt more efficiently to low light conditions in terms of photosynthetic efficiency.

TABLE 5. Carbon assimilation rates of wild type and PLANT-1 plants grown under normal (A) and low light (B) conditions. TABLE 5 A: Normal light grown.

Light Intensity CO? Assimilation (micromol/m²/s)

(micro Einstein/m2/s) Wild-type PLANT-1

0 -1.29 +1- 0.20 -1.72 4-/- 0.08

35 0.48 +/- 0.14 0.31 +1- 0.03

70 2.46 4-/- 0.15 1.98 4-/- 0.16

100 3.63 4-/- 0.31 3.36 +/- 0.27

200 5.96 4-/- 0.13 6.31 4-/- 0.4

400 6.74 4-/- 0.26 7.33 +/- 0.69

800 6.95 4-/- 0.26 7.56 4-/- 0.69

1200 7.29 +1- 0.29 8.07 4-/- 0.8

TABLE 5 B: Low light grown.

Light Intensity CO? Assimilation (micromol/m²/s^')

(micro Einstein/m2/s) Wild-tvoe PLANT-1

0 -1.52 4-/- 0.17 -1.41 4-/- 0.16

35 0.48 +1- 0.16 0.62 4-/- 0.06

70 1.13 4-/- 0.28 1.81 4-/- 0.45

100 1.824-/- 0.20 3.09 4-/- 0.31

200 2.18 4-/- 0.17 3.77 4-/- 0.59

400 2.50 4-/- 0.23 4.35 4-/- 0.55

800 2.88 4-/- 0.23 4.904-/- 0.52

1200 3.07 4-/- 0.20 5.53 +/- 0.47

Similar results could be observed in soy plants over expressing the Arabidopsis CCAl gene behind the e35S promoter. EXAMPLE 9 The following example describes the comparison of metabolite contents in plants of the present invention in comparison with natural plants. Carbohydrates are the primary products of photosynthesis. Increases in several metabolites, including many mono- and disaccharides and starch were apparent in plants transformed to express the CCAl gene product. The amount of total soluble sugar from leaves was determined by extracting total sugar by coupled enzymatic assay as described by Angelov M.N, Sun J, Byrd GT, Brown RH, and Black CC in Photosynthesis Research 38: 61-72, 1993. Six mm diameter punches were taken from two leaves of plants of the present invention and natural plants over the period of 24 hours and extracted three times in 80% ethanol. Extracted sugar was dried at 60° C then resuspended in water. Total sugar was determined by measuring the formation of NADH at 340 nm in the presence of NAD+, ATP, hexokinase, glucose-6-phosphate dehydrogenase, phosphoglucoisomerase, and invertase. Leaf starch present in the same leaf punches was extracted from the punches and digested to glucose by homogenizing the punches in 0.5 N NaOH, boiling for 10 min, titrating the pH to 5.5 with acetic acid, then treating with amyloglucosidase(Winder T.L., Sun J., Okita T.W., Edwards G.E., Plant Cell Physiol 39: 813-820, 1998). The resulting glucose equivalents were determined similarly to total leaf soluble sugar as described above (Angelov M.N., Sun J., Byrd G.T., Brown R.H., and Black CC, Photosynthesis Research 38: 61-72, 1993). Leaf total sugar was highly elevated in PLANT-1 plants compared to wild-type plants, particularly during daylight hours, whereas leaf starch was modestly increased in PLANT-1 plants (Table 6).

TABLE 6: Over expression of CCAl increases total leaf soluble sugar and starch. Plants were grown on a 16 h light, 8 h dark cycle. Negative time points indicate time before lights on; positive time points indicate time after lights on. Sugar and starch are expressed in micromole. glucose equivalents/cm² leaf tissue.

Increases in sugars, amino acids and other metabolite in plants of the present invention were identified by tandem mass spectrometry after liquid chromatographic separation as described by Lily Li et al (Lily Li et al, Annual conference of American Society of Mass Spectrometry, June 1-4, 2002; Orlando, Florida). Lines PLANT-2 and PLANT-1 expressing CCAl gene product and natural plants were grown in soil under 16 h light 8 h dark conditions. Rosette leave tissue was taken from stage 1.10 (10 rosette leaf stage) Arabidopsis plants. Leaves from 1 to 10 plants were taken and pooled for each time point after light exposure of 0.5h, 4h, and 8h. Samples were flash frozen, lyophilized and stored at -80°C prior to extraction and analysis. Notable increases in glucose, fructose, raffinose and sucrose and were observed in CCA-1 plants. In addition to sugars, methionine was also observed to be elevated inCCA-1 plants as compared to wild-type plants.

TABLE 7: Fold increase of metabolites in PLANT-2 plants relative to wild-type plants exposed to light for indicated amount of time in hours. Plants were grown on a 16 h light, 8 h dark cycle. PLANT-2 plants in PLANT-1 plants Light exposure time Light exposure time 0.5 h 4 h 8 h 0.5 h 4 h 8_h

Fold Glucose Increase 5.5 5.8 5.4 6.1 11.1 6.6

Fold Fructose Increase 4.1 4.6 2.8 3.6 6.7 3.9

Fold Raffinose Increase 2.1 2.4 3.6 2.9 6.5 4.9

Fold Sucrose Increase 1.4 1.6 1.6 1.4 2.1 1.6

Fold Methionine Increase 1.6 6.1 2.7 2.1 14.6 1.2

EXAMPLE 10 The following example describes the effect of CCA-1 gene expression on the morphology of Arabidopsis plants. Over expression of CCAl behind a constitutive promoter results in Arabidopsis plants with altered morphology. However, the altered morphology can be corrected by the expression of CCAl behind light regulated promoters. For example, Arabidopsis lines PLANT-1 and PLANT-2, which over express Arabidopsis CCAl behind the e35S promoter, have elongated hypocotyls, petioles, and leaves compared to wild-type plants. Over expression of CCAl by the light-regulated Arabidopsis RbcS promoter by construct pMON56622, produced plants that had hypocotyl, petiole and leaf morphologies that ranged from normal to elongated, but the overall trend of expression behind the RbcS promoter was to correct leaf morphology abnormalities observed with over expression behing the e35S promoter. For example, unlike PLANT-2 and PLANT-1 plant lines pMON56622-12919 and pMON56622-12936 had nearly normal hypocotyl, and leaf morphology except for slightly elongated petioles. The same effect was demonstrated for plants transformed with pMON67293 that expresses CCAl behind the light-regulated Arabidopsis Rubisco activase Rca promoter. 32 lines generated with pMON67293 appeared identical to wild-type plants despite the fact that 7 of the 32 lines had equal or higher CCAl transgene mRNA expression relative to those expressing CCAl behind the 35S promoter. Over expression behind the Arabidopsis RbcS promoter also resulted in increased total leaf soluble sugar. Plants transformed with pMON56622, lines 12919 and 12934 were grown with wild-type plants to stage 1.10 (10 rosette leaf stage) under a 16h light/8 h dark cycle. Leaf total soluble sugar extracted from leaf punches was determined by coupled enzymatic assay. For the determination of leaf total soluble sugar content of pMON56622 and wild-type Arabidopsis plants, a 6 mm diameter punch was taken after 8 h in the light and extracted three times in 80% ethanol. Extracted sugar was dried at 60 C then resuspended in water. Total sugar was determined by measuring the formation of NADH at 340 nm in the presence of NAD+, ATP, hexokinase, glucose-6-phosphate dehydrogenase, phosphoglucoisomerase, and invertase. TABLE 8:

EXAMPLE 11 This example describes how to create soil based simulated drought conditions and evaluation of drought stress in Arabidopsis plants, eg. plant-1, plant-2, plant-3 or plant-4 containing genes of the invention as well as plants with empty vector. The photographs .were taken with an OLYMPUS Camedia C-2500L digital camera, setting at Aperture mode and resolution at HQ, as described in instruction manual of the camera. Two inch pots were filled with Metromix 200 (Scotts-Sierra Horticultural Products Co., Marysville, OH) planting mix. Each pot was adjusted to a weight of 37+/- lgram prior to immersing the flat in nutrient solution (100 PPM of Peters 20:20:20; Scotts-Sierra Horticultural Products Co., Marysville, OH; Stock Number 91010) for water and nutrient saturation. These pots were stored at 4 degree C for approximately three days, then transferred to 22°C/18°C, 16-hr-light 8-hr-dark, 150 μmol m^"2 sec^"1 with 70% relative humidity. After seed germination pots were thinned for a plant density of 1 plant/pot and allowed to grow until bolting/first flower open, which was usually 4-5 weeks after sowing. For normal growth conditions the pots were rotated every day, watered 2 times every week and fertilized with the same nutrient solution once in 10 days. For drought simulation, plants were selected randomly from flats as described above and the pots were saturated with water by sub-irrigation for 30 minutes. At this stage, a pre-drought phenotype was' recorded as photographs. Excess water was drained and the weight of each pot was recorded. Control plants were treated as described in the above paragraph. Water was then withheld for 7-8 days from experimental plants. After 7-8 days drought injury phenotype was scored, and plants were photographed. At this time, various physiological tests such as photosynthesis rate, leaf relative water content, leaf water potential and chlorophyll fluorescence were performed on experimental and control plants. After the testing, experimental plants were watered with 25% of water capacity, that is approximately 25% of water that was needed for saturation of soil in the pots (~ 25 ml). Three days after watering the experimental plants, all measurements were repeated along with photographic records of experimental and control plants. All pots were saturated with nutrient solutions at this stage and the phenotype was recorded for seven days without watering. Drought scoring in Arabidopsis plants was done by taking a photograph of the soil based drought assay scoring system in Arabidopsis plants, where A) were healthy plants, no difference from control plants; B) were near wilting, leaves becoming wilted; C) were wilted green recoverable plants after watering, D) were severely wilted, anthocyanic plants and not recoverable after watering. No visual difference under drought conditions was observed for wild type plants as compared to plants transformed with an empty cloning vector (see Table 9 and 10); therefore physiological measurements were done only in wild type (WT) plants and compared with plants transformed with constructs of the present invention.

TABLE 9. Phenotype scoring of Arabidopsis plants after 7-8 days simulated drought

TABLE 10. Phenotype scoring of Arabidopsis plants under drought simulation, 3 days after watering with 25% water potential.

EXAMPLE 12 The following example describes the effect of CCA-1 gene expression on water pressure in Arabidopsis plants. Water pressure was used in the art to predict the movement of liquid water into or out of a plant cell. The water potential difference across a membrane determines the direction of flow. Water moves spontaneously from regions of high water potential from adjoining regions of high water potential to regions of low water potential. Leaf water potential was measured by sealing a sample tissue in a chamber containing a thermocouple. After an equilibration period a cooling current was applied to the thermocouple to condense water on the thermocouple junction. The amount of condensed water was proportional to the water potential of the sample tissue. Condensed water was allowed to evaporate causing a change in the thermocouple output. This output was calibrated for water potential, using a salt solution. Water potential was measured with commercially available 14-channel thermocouple psychrometer manufactured by Wescor/Campbell Water Potential System C-52 sample chambers (WESCOR, Logan Utah), plus CR 7 Measurement & Control System (Campbell, Logan, Utah)] as per manufacturers instructions. Results of water potential measurement are shown in Table 10. Transgenic Plant-3 shows a surprisingly low ratio of water potential difference under normal compared to drought conditions (ratio D/N, 1.10). This result indicates that transgenic plants containing SEQ ID NO: 2 polypeptides exhibit near normal water potential under drought conditions. TABLE 11. Water potential measurement on wild type and transgenic plant line Plant- 1 and Plant-2 expressing CCA-1 polypeptide under normal and simulated drought conditions.

EXAMPLE 13 The following example describes the effect of CCA-1 gene expression on relative water content of Arabidopsis plants. Relative water content (RWC) is another physiological measure of plant water deficit. It measures the effect of osmotic adjustment in plant water status, when a plant is under stressed conditions. RWC was measured in small leaf samples and it reflects on the mass of water held in relation to the mass that can be held at full turgor pressure. For measuring RWC, leaf samples were taken into an airtight container, weighed (W) and floated on or set in water for 4 hours, after that they are weighed again to determine turgid weight (TW). After these measurements, the leaf sample was dried in an oven at 80° C for 24 hours and weighed to determine dry matter weight (DW). All weights were in grams but they can be measured in any unit of mass measurements. For measurement of relative water content in plants of the present invention, plants were subjected to simulated drought conditions as described in Example 11. RWC was determined by the following equation: RWC = [Fresh Weight- Dry Weight)/(Turgid Weight - Dry Weight)] x 100. Results of RWC in plants of present invention (Plant-3) are presented in Table 7. These results demonstrate approximately 27 % more water is retained in leaves of transgenic plants with SEQ ID NO:l gene product as compared to wild type leaves. TABLE 12: Measurement of relative water content (RWC) in leaves from wild type plants and transgenic leaves from Plant- 1 and Plant-2

Claims

WE CLAIM:

1. A method for producing a transgenic plant with an improved agronomic characteristic comprising the steps of: a) transforming a plant cell with a DNA construct comprising a promoter that functions in plant cells, operably linked to a DNA polynucleotide molecule that encodes a protein selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16 and SEQ ID NO: 18, or a protein substantially homologous thereto, and operably linked to a 3' termination region; and b) regenerating said transformed plant cell into a transgenic plant containing said DNA construct; and c) screening said transgenic plant containing said DNA construct for the presence of an improved agronomic characteristic wherein said improved agronomic characteristic is selected from the group consisting of a higher rate of photosynthesis, higher rate of carbon assimilation, and increased tolerance to plant environmental stress conditions as compared to a plant of the same species as said transgenic plant that does not contain said DNA construct; and d) selecting the transgenic plant containing at least one of the said improved agronomic characteristics.

2. The method of claim 1, wherein said promoter is plant virus promoter.

3. The method of claim 1, wherein said promoter comprises a heterologus plant promoter.

4. The method of claim 1, wherein said promoter comprises a tissue enhanced or tissue specific plant promoter.

5. The method of claim 1, wherein said promoter comprises a native gene plant promoter.

6. The method of claim 1, wherein said DNA molecule is substantially homologous to a DNA molecule selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 15, SEQ ID NO: 17, and SEQ ID NO: 19.

7. The method of claim 1, wherein said tolerance to plant environmental stress condition is tolerance to drought.

8. The method of claim 1, wherein said plant cell is selected from the group consisting of alfalfa, corn, soybean, wheat, cotton, rice and rapeseed/canola.

9. A transgenic plant with higher rate of photosynthesis, higher rate of carbon assimilation, and increased tolerance to plant environmental stress conditions, as compared to a plant of a same plant species comprising a DNA construct, wherein said DNA construct comprises a promoter that functions in plants, operably linked to a DNA molecule that encodes a protein substantially homologous to a protein selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16, and SEQ ID NO: 18, and operably linked to a 3'termination region.

10. The method of claim 9, wherein said tolerance to plant environmental stress condition is tolerance to drought.

11. The method of claim 9, wherein said promoter is plant virus promoter.

12. The method of claim 9, wherein said promoter comprises a heterologus plant promoter.

13. The method of claim 9, wherein said promoter comprises a tissue enhanced or tissue specific plant promoter.

14. The method of claim 9, wherein said promoter comprises a native gene plant promoter.

15. The progeny of said transgenic plant of claim 9.

16. The transgenic plant of claims 9 wherein said transgenic plant is selected from the group consisting of alfalfa, corn, soybean, wheat, cotton, rice and rapeseed/canola.

17. A plant part produced by said transgenic plant of claim 9 comprising leaves, roots, stems, shoot, flowers, fibers, fruit, or seed.

18. A DNA construct, wherein said DNA construct comprises a promoter that functions in plants, operably linked to a DNA molecule that encodes a protein substantially homologous to a protein selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16, and SEQ ID NO: 18, and operably linked to a 3'termination region.

19. The DNA construct of claimlδ, wherein said protein comprises at least a N- terminal 50% portion of a protein selected from the group consisting of: SEQ ID. NO: 2, SEQ ID. NO: 4, SEQ ID. NO: 6, SEQ ID. NO: 8, SEQ ID. NO: 10, SEQ ID. NO: 12, SEQ ID. NO: 14, SEQ ID. NO: 16, and SEQ ID. NO: 18.

20. The DNA construct of claimlδ, wherein said protein comprises at least a N- terminal 60% portion of a protein selected from the group consisting of: SEQ ID. NO: 2, SEQ ID. NO: 4, SEQ ID. NO: 6, SEQ ID. NO: 8, SEQ ID. NO: 10, SEQ ID. NO: 12, SEQ ID. NO: 14, SEQ ID. NO: 16, and SEQ ID. NO: 18.

21. The DNA construct of claim 18, wherein said DNA construct comprises a promoter that functions in crop plants, operably linked to a DNA molecule substantially homologous a DNA molecule selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 15, SEQ ID NO: 17, and SEQ ID NO: 19, and operably linked to a 3'termination region.