MX2007004082A - Scarecrow-like stress-related polypeptides and method sof use in plants - Google Patents

Abstract

A transgenic plant transformed with an'SLSRP coding nucleic acid, wherein expression of the nucleic acid sequence in the plant results in increased growth under water-limited conditions and/or increased tolerance to an environmental stress as compared to a wild type variety of the plant. Also provided are agricultural products, including seeds, produced by the transgenic plants. Also provided are isolated SLSRPs, and isolated SLSRP coding nucleic acids, and vectors and host cells containing the latter.

Description

SCARECROW SYMBOL POLYPEPTIDES RELATED TO STRESS AND METHODS OF USE IN PLANTS BACKGROUND OF THE INVENTION Field of the Invention The present invention relates generally to nucleic acid sequences encoding polypeptides associated with growth and / or with responses to abiotic stress and / or tolerance to abiotic stress in plants. In particular, the present invention relates to polypeptide-encoding nucleic acid sequences that increase plant growth under conditions of limited water availability and confer plants tolerance to drought, cold and / or salts. Background in the art Environmental abiotic stresses, such as drought stress, salinity stress, heat stress and cold stress, are important limiting factors of plant growth and productivity. Crop losses and crop yield losses of major cereals such as soybeans, rice, maize, cotton, and wheat caused by these stresses represent a significant economic and political factor, and contribute to the lack of food in many countries. underdeveloped countries. In general, the plants are exposed during their life cycle to conditions of reduction of the environmental water content. Most plants developed strategies to protect against these drying conditions. However, if the severity and duration of the drought conditions are too great, the effects on the development, growth, and yield of most grain plants are profound. Continuous exposure to drought conditions causes significant alterations in plant metabolism, which ultimately lead to cell death and consequent yield losses. The development of stress-tolerant plants is a strategy that involves the possibility of solving or mediating at least part of these problems. However, traditional strategies of plant cultivation, in order to develop new plant lines that exhibit resistance (tolerance) to these types of stress are relatively slow and require specific resistant lines for crossing with the desired line. The limited germplasm resources for stress tolerance and the incompatibility of crosses between plant species with distant relationships represent significant problems found in conventional crops. In addition, cellular processes conducive to tolerance to drought, cold and salts in model plants of tolerance to drought and / or salts are complex in nature and include multiple mechanisms of cellular adaptation and numerous metabolic pathways. This multi-component nature of tolerance to stress has not only caused the cultivation of tolerance to largely fail, but also limited the ability to genetically engineer stress-tolerant plants by biotechnological methods. The common damages due to the different stresses such drought, salinity and cold stress, seem to be due, for the most part, to dehydration (Smirnoff, 1998, Curr Opin Biotech 9: 214-219). Drought tolerant plants (water stress) and plants sensitive to drought can be clearly distinguished by the remarkable accumulation of ions and solutes tolerant plants, which leads to osmotic adjustments in plants (Bohnert HJ and Jensen. 1996, TIBTECH 14: 89-97). The conditions of drought and high salt content can correspond to mineral nutrition as a consequence of 1) reduced transport of ions from the soil to the roots; and / or 2) modification of the uptake of ions by the roots. The SCARECROW gene (SCR) was identified in Arabidopsis and is expressed specifically in plant root tissues of plant embryos and in certain tissues of the root and stem. The SCR gene encodes a new possible transcription factor and is required for the asymmetric cell division of an Arabidopsis root. Modulation of SCR expression levels can be used to advantageously modify the root and aerial structures of transgenic plants and improve the agricultural properties of these plants. The mutation of the SCR gene results in a defect in the radial pattern and loss of a layer of basal tissue from the root.

Pysh et al. Identified a number of expressed Arabidopsis (EST) sequence tags similar to the SCR amino acid sequence of Arabidopsis and termed them Scarecrow simile genes (SCL) (Pysh et al., 1999, Plant J. 18: 1 11 -1 19). The SCL genes comprise a new family of genes, called the GRAS family of genes, based on the site designations of the three genes: the gibberellin-insensitive site (GAI), the GA1 repressor site (RGA) and the site scarecrow (SCR). It was reported that GRAS / SCL gene products are restricted to higher plants and are plant-specific proteins that participate in various evolutionary processes. The members of the GRAS / SCL family have a highly conserved C-terminal and variable N terminal, which contains five motifs capable of being recognized: the heptadimer repeat of leucines I (LHR I), the VHIID motif motif, the heptadimer repeat of leucines II ( LHR II), the PFYRE motif, and the SAW motif.

The GRAS / SCL proteins act as transcription factors but are not restricted in their role in asymmetric cell division. For example, it was shown that the PAT1 protein intervenes in the signal transduction of phytochrome A from Arabidopsis thaliana (Bolle et al., Genes Dev., 2000, 14: 1269-1278), and the tomato suppressor gene Lateral (Ls) intervenes in the formation of lateral branches. Two members of the GRAS family, the GAI and RGA genes, play important roles in the signal transduction pathway of gibberellin acid (GA). Arabidopsis plants with a GAI site mutation do not respond to GA of exogenous application and have low height (Koorneef et al., 1985, Physiol. Plant 65: 33-39). The rice SLR1 was identified as a GAI ortholog and was shown to intervene in the GA signal pathway of maize, rice, barley, grape and wheat (Hynes et al., 2003, Transgenic Research 12: 707-714). Overexpression of GAI from Arabidopsis in tobacco and rice produces a dwarf phenotype, compared to a wild-type plant (Hynes et al., 2003, Transgenic Research 12: 707-714). There is a fundamentally restricted physico-chemical compensation in all terrestrial photosynthetic organisms, between the absorption of carbon dioxide (C02) and water loss (Taiz and Zeiger, 1991, Plant Physiology, Benjamin / Cummings Publishing Co., p 94). The C02 must be in aqueous solution for the action of C02 binding enzymes such as Rubisco (ribulose-1,5-bisphosphate-carboxylase / oxygenase) and PEPC (phosphoenolpyruvatecarboxylase). Since a humid cell surface is required for the diffusion of C02, it is inevitable that evaporation takes place when the humidity is less than 100% (Taiz and Zeiger, 1991, page 257). Plants have numerous physiological mechanisms to reduce water loss (eg serous cuticles, stomatal closure, hairy leaves, sunken positions in stomata). Since these barriers do not discriminate between the water flow and C02, these water conservation measures also act as resistance to C02 uptake (Kramer, 1983, Water Relations of Plants, Academic Press p.305). The photosynthetic uptake of C02 is an absolute requirement for the growth of plants and the accumulation of biomass in photoautotrophic plants. Water use efficiency (WUE) is a commonly used parameter to estimate the trade-off between water consumption and C02 uptake / growth (Kramer, 1983, Water Relations of Plants, Academic Press p 405). WUE has been defined and measured in many ways. One approach is to calculate the dry weight ratio of the whole plant, with respect to the weight of water consumed by the plant during its life (Chu et al., 1992, Oecologia 89: 580). Another variation is to use a shorter time interval when measuring biomass accumulation and water use (Mían et al., 1998, Crop Sci. 38: 390). Another approach is to use measures from restricted parts of the plant, for example, only the measurement of air growth and the use of w (Nienhuis et al 1994 Amer J Bot 81: 943). WUE was also defined as the relationship between C02 uptake and the loss of w vapor from a leaf or a portion of a leaf, often measured over a very short period (eg seconds / minutes) (Kramer, 1983 , p 406). The fixed 13C / 12C ratio in plant tissue was also used, and measured with a mass spectrometer with isotopic ratio, to estimWUE in plants by photosynthesis of C3 (Martin et al., 1999, Crop Sci. 1775). The increase in WUE indic a relatively improved efficiency of growth and w consumption, but this isol information does not indicif one of the two processes changed or if both changed. In the selection of traits to improve crops, an increase in WUE due to a decrease in w use, without a change in growth, would have particular merit in an agricultural system with irrigation, in which the costs of w entry are high. An increase in WUE due mainly to an increase in growth without a corresponding increase in w use would be applicable to all agricultural systems. In many agricultural systems in which the provision of w is not limiting, an increase in growth, even at the expense of an increase in w use (ie without change of WUE), can also increase yield. Consequently, new methods are required to increase WUE and the accumulation of biomass to improve agricultural productivity. Since WUE integr many physiological processes rel to the primary metabolism and the use of w, in general it is a very polygenic trait with a large genotype with environmental interaction (Richards et al., 2002, Crop Sci. 42: 111). For these and other reasons, few attempts to select WUE changes in traditional cropping programs have been successful. Although some genes involved in plant growth and / or stress responses in plants have been characterized, the characterization and cloning of plant genes that confer stress tolerance and / or growth enhancement in limited w conditions remain largely incomplete and fragmented. For example, certain studies indicthat stress due to drought and salts in some plants may be due to the additive effects of the genes, in contrast to other investigations, which indicthat specific genes are activ by transcription in the vegetative tissue of plants under conditions of osmotic stress. Although it is generally assumed that stress-induced proteins play an important role in stress tolerance, direct evidence is still lacking, and the functions of many stress response genes are unknown. Accordingly, there is a need to identify additional genes expressed in plants and stress tolerant and / or w-efficient plants that have the ability to confer stress resistance and / or increased growth in w conditions limited to the host plant and to other plants. vegetable species. Stress tolerant plants and / or plants that are efficient in the use of newly developed w will have many advantages, such as an increase in the range in which cereal plants can be grown, for example, by decreasing the w requirements of a species vegetable. The growth and yield of the plant and the crop are generally limited by the availability of w. By increasing plant growth in conditions of limited w availability, crop yields from all major global markets can be increased. SUMMARY OF THE INVENTION The present invention covers in part the need to identify new and unique polypeptides and nucleic acids capable of increasing growth under limited w conditions and / or conferring stress tolerance to plants upon modification of expression. The present invention describes a new genre of stress-rel Scarecrow-like polypeptides (SLSRP) and nucleic acids encoding SLSRP of importance for plant growth and modulation of the response to a plant at environmental stress. More particularly, to the modification of the expression of those nucleic acids encoding SLSRP in a plant, which result in increased plant growth under limited water conditions and / or increased tolerance to environmental stress. Accordingly, the present invention includes an isolated plant cell comprising a nucleic acid encoding SLSRP, wherein the expression of the nucleic acid sequence in the plant cell results in increased growth of the plant under limited water conditions and / or greater tolerance to environmental stress, compared to a wild type variety of the plant cell. Preferably, the SLSRPs come from Physcomitrella patens or Glycine max. Namely, the genes of Physcomitrella patens Scarecrow, PpSCLI (SEQ ID NOs: 1 and 2), PpSCL2 (SEQ ID NOs: 3 and 4), PpSCL3 (SEQ ID NOs: 5 and 6) are described herein, and the gene of Glycine max simile Scarecrow, GmSCU (SEQ ID NOs: 7 and 8). The invention provides that in some embodiments SLSRP and encoding nucleic acids are those found in the genera Physcomitrella or Glycine. In another preferred embodiment, the nucleic acids and polypeptides are derived from a Physcomitrella patens plant or a Glycine max plant. In one embodiment, the invention provides that plants expressing SLSRPs demonstrate an increase in growth under limited water conditions. In another embodiment, the increase in plant growth is due to the increase in Water Use Efficiency (WUE), compared to a wild type variety of the plant. In another embodiment, the invention provides that plants that overexpress SLSRP demonstrate an increase in Dry Weight (DW), compared to a wild type variety of the plant. In still another embodiment, the invention provides that plants that overexpress the SLSRP demonstrate an increase in tolerance to environmental stress, compared to a wild-type variety of the plant. The invention provides that environmental stress may be stress by salinity, drought, temperature, metal, chemical, pathogenic and oxidative stress, or combinations thereof. In preferred embodiments, environmental stress may be selected from one or more of the group consisting of drought, high salt content and low temperature. The invention also provides seeds produced by transgenic plants transformed by nucleic acids encoding SLSRP, wherein the seed comprises the nucleic acids encoding SLSRP and wherein the plants are true cultures for increasing growth under limited water conditions and / or increasing the tolerance to environmental stress, compared to a wild type variety of the plant. In a preferred embodiment, the invention provides seeds produced by a transgenic plant transformed with a nucleic acid encoding PpSCLI, PpSCL2, PpSCL3, or GmSCLI, where the plants are true cultures for growth enhancement under limited water conditions and / or increased tolerance to environmental stress, compared to a wild type variety of the plant. The invention also provides an agricultural product produced by any of the transgenic plants, plant parts or seeds described below. The invention also provides isolated SLSRPs that are described below. The invention also provides nucleic acids coding for isolated SLSRP encoding nucleic acids, wherein the SLSRP nucleic acid encodes an SLSRP as described below. The invention also provides isolated recombinant expression vectors comprising nucleic acids encoding SLSRP as described below, wherein expression of the vectors in a host cell results in growth enhancement under limited water conditions and / or increase in tolerance to environmental stress compared to a wild-type variety of the host cell. The invention also provides host cells containing the vectors and plants containing the host cells. The invention also provides methods for producing transgenic plants with a nucleic acid coding for SLSRP nucleic acid, wherein the expression of nucleic acid in plants results in increased growth under limited water conditions and / or increased tolerance to environmental stress, compared to a wild-type variety of the plant comprising: a) transforming a plant cell with an expression vector comprising a nucleic acid encoding SLSRP, and b) generating from the plant cell in a transgenic plant with an increase in growth under limited water conditions and / or an increase in tolerance to environmental stress , compared with a variety of wild type of the plant. In a preferred embodiment, the nucleic acids encoding SLSRP and SLSRP are as described below. The present invention also provides a method for identifying a new SLSRP, comprising a) generating a specific antibody response against SLSRP antibody, or its fragment, as described below; b) the search for possible SLSRP material with the antibody, where the specific binding of the antibody to the material indicates the presence of a possible new SLSRP; and c) identifying a new SLSRP from the set material compared to known SLSRPs. Alternatively, hybridization with nucleic acid probes as described below can be used to identify the nucleic acids encoding new SLSRP. The present invention also provides methods for modifying the growth or stress tolerance of a plant comprising modifying the expression of an SLSRP encoding nucleic acid in the plant, wherein the SLSRP is as described below. The invention provides that this method can be carried out in such a way that growth and / or stress tolerance is increased or decreased. Preferably, growth and / or stress tolerance increase in a plant through modification of the expression of a nucleic acid encoding SLSRP.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows the phylogenetic tree of the described amino acid sequence PpSCLI (SEQ ID NO: 2) with sequences of six known members of the GRAS family. The diagram was generated by Align X of Vector NTI Figure 2 shows the phylogenetic tree of the described amino acid sequence PpSCLI, PpSCL2, PpSCL3, and GmSCLI (SEQ ID NOs: 2, 4, 6, and 8) with six member sequences known of the GRAS family. The diagram was generated by Align X of Vector NTI. Figure 3 shows the phylogenetic tree of the described amino acid sequence PpSCLI, PpSCL2, PpSCL3, and GmSCLI (SEQ ID NOs: 2, 4, 6, and 8) with six member sequences known from the GRAS family. The diagram was generated by Align X of Vector NTI. The white-on-black source is a consensus residue derived from a block of similar residues in a certain position. The black-on-gray source is the consensus amino acid or similar in a position with a residue consensus in at least 50% of the sequences. Non-similar residues in a certain position are identified as a black-on-white source. Figure 4 shows the nucleotide sequence of PpSCLI (EST 386) (SEQ ID NO: 1). Figure 5 shows the deduced amino acid sequence of PpSCLI (SEQ ID NO: 2) Figure 6 shows the nucleotide sequence of PpSCL2 (EST 166) (SEQ ID NO: 3) · Figure 7 shows the amino acid sequence deduced from PpSCL2 (SEQ ID NO: 4) Figure 8 shows the nucleotide sequence of PpSCL3 (EST 512) (SEQ ID NO: 5). Figure 9 shows the deduced amino acid sequence of PpSCL3 (SEQ ID NO: 6). Figure 10 shows the nucleotide sequence of soybean bean GmSCLI (GM59556757) (SEQ ID NO: 7). Figure 1 1 shows the deduced amino acid sequence of soy bean GmSCLI (SEQ ID NO: 8). DETAILED DESCRIPTION OF THE INVENTION The present invention can be understood more easily with reference to the following detailed description of the embodiments of Preference of the invention and the examples included therein. However, before describing the present compounds, compositions, and methods it should be understood that the present invention is not limited to specific nucleic acids, specific polypeptides, specific cell types, specific host cells, specific conditions, or specific methods, etc., since they can obviously vary, and the numerous modifications and variations there will be apparent to those skilled in the art. It should also be understood that the terminology used there is only intended to describe specific embodiments and is not intended to be limiting. In particular, the designation of the amino acid sequences such as "Scarecrow-like similiar polypeptides related to stress," or "SLSRP", in no way limit the functionality of said sequences. The present invention describes a new genus of SLSRP and SLSRP encoding nucleic acids of importance for increasing plant growth under limited water conditions and / or modulating the response of a plant to environmental stress. More particularly, the modification of the expression of the nucleic acids encoding SLSRP is a plant resulting in increased growth under limited water conditions and / or increased tolerance to environmental stress. Representative members of the SLSRP genus are PpSCLI (SEQ ID NOs: 1 and 2), PpSCL2 (SEQ ID NOs: 3 and 4), PpSCL3 (SEQ ID NOs: 5 and 6), and GmSCLI (SEQ ID NOs: 7 and 8) . Accordingly, the present invention encompasses SLSRP polynucleotides and polypeptides and their use to increase the growth of a plant under limited water conditions and / or increase a plant's tolerance to environmental stress. In one embodiment, the SLSRPs come from a plant, preferably a Physcomitrella or Glycin plant, and more preferably a Physcomitrella patens or Glycine max plant. In another preferred embodiment, the SLSRPs are PpSCLI as defined in SEQ ID NOs: 1 and 2; PpSCL2 as defined in SEQ ID NOs: 3 and 4; PpSCL3 as defined in SEQ ID NOs: 5 and 6; or GmSCLI as defined in SEQ ID NOs: 7 and 8. The described SLSRP polypeptide sequences (SEQ ID NOs: 2, 4, 6, and 8) have significant sequence homology to the sequence of known members of the GRAS family. For example, the PpSCLI sequence has 42% sequence identity and 30% sequence similarity to the Q7X9T5 protein sequence (L Longiflorum SCL), 42% identity and 30% similarity to the Q8S2B3 protein sequence (rice) , 42% identity and 30% similarity to the T02531 protein sequence (scarecrow gene regulator of Arabidopsis), 39% identity and 27% similarity to the protein sequence Q94HJ4 (possible scarecrow regulatory gene), 21% of identity and 15% similarity with the protein sequence Q9LNX6 (Arabidopsis) and 24% identity and 16% similarity to the T02736 protein sequence (scarecrow regulator gene of Arabidopsis). The PpSCL2 sequence has 26% sequence identity and 39% similarity to the NP190990 protein sequence (possible scarecrow transcription factor of A. thaliana), 26% identity and 39% similarity to the T51244 protein sequence ( scarecrow protein from A. thaliana), 24% identity and 38% similarity to the Q6L5Z0 protein sequence (Oryza sativa scarecrow), 24% identity and 38% similarity to the Q9FUZ7 protein sequence (scarecrow of Zea mays ), and 20% identity and 31% similarity to the protein sequence Q9AVK4 (scarecrow of Pisum sativum). The PpSCL3 sequence has 40% sequence identity and 49% similarity to the NP199626 protein sequence (A. thaliana phytochrome A signal transduction 1), 37% identity and 45% similarity to the Q8GYN7 protein sequence. (possible scarecrow gene regulator of A. thaliana), 42% identity and 54% similarity with the protein sequence NP_175475 (transcription factor 5 scarecrow simile of A. thaliana), 40% identity and 51% similarity with the protein sequence E966542 (scarecrow simile protein from A. thaliana), and 41% identity and 54% similarity to the protein sequence Q7EXH0 (possible scarecrow protein from A. thaliana). The GmSCLI sequence has 45% sequence identity and 58% similarity to the protein sequence NP_200064 (transcription factor 8 scarecrow simile of A. thaliana), 32% identity and 47% similarity to the BAD27826 protein sequence ( OsGAl protein insensitive to gibberellin from O. sativa), 28% identity and 40% similarity with protein sequence NP_915059, 1 (scarecrow O. sativa protein) and 19% identity and 27% sequence similarity of protein AF036300_1 (scarecrow-1 simile of A. thaliana). The present invention provides a transgenic plant cell transformed by a nucleic acid encoding SLSRP, wherein the expression of the nucleic acid sequence in the plant cell results in an increase in growth under limited water conditions and / or increased tolerance to an environmental stress, compared to a wild type variety of the plant cell. The invention also provides parts of transgenic plants and transgenic plants containing the plant cells described herein. The term "plant" as used herein refers to whole plants, plant cells, and parts of plants, including seeds. Parts of plants include, without limitation, stems, roots, ovules, stamens, leaves, embryos, meristematic regions, callus tissue, gametophytes, sporophytes, pollen, microspores, and the like. In one embodiment, the transgenic plant is sterile male. A plant seed produced by a transgenic plant transformed by a nucleic acid coding for SLSRP is also provided, wherein the seed contains the nucleic acid encoding SLSRP, and wherein the plant is a true culture for increasing growth under limited water conditions. and / or increased tolerance to environmental stress, compared with a variety of wild type of the plant. The invention also provides a seed produced by a transgenic plant expressing an SLSRP, wherein the seed contains the SLSRP, and wherein the plant is true culture to increase growth under limited water conditions and / or increase tolerance to stress environmental, compared to a variety of wild type of the plant. The invention also provides an agricultural product produced by any of the transgenic plants described below, plant parts, and plant seeds. Agricultural products include, without limitation, plant extracts, proteins, amino acids, carbohydrates, fats, oils, polymers, vitamins, and the like. As used herein, the term "variety" refers to a group of plants in a species that shares constant characters that separate them from the typical form and from other possible varieties within said species. Although it has at least one distinctive feature, a variety is also characterized by having some variation among individuals among the variety, based mainly on the Mendelian segregation of traits among the progeny of successive generations. A variety is considered a "true crop" for a particular trait if it is genetically homozygous for that trait to the extent that, when the true crop variety is self-pollinated, a significant amount of segregation independent of the trait between the progeny is not observed. In the present invention, the trait originates in the transgenic expression of one or more DNA sequences introduced into a plant variety. As also used herein, the term "wild-type variety" refers to a group of plants that are analyzed for comparative purposes as a control plant, wherein the wild-type variety plant is identical to the test plant. (plant transformed with an SLSRP or plant in which the expression of the nucleic acid coding for SLSRP has been modified) with the exception that the wild-type variety plant has not been transformed by a nucleic acid encoding SLSRP and / or the Expression of the nucleic acid encoding SLSRP in the wild-type variety plant has not been modified. The present invention discloses that the SLSRPs of Physcomitrella patens and Glycine max are useful for increasing the growth of a plant under limited water conditions and / or tolerance to environmental stress. As used herein, the term "polypeptide" refers to a chain of at least four amino acids joined by peptide bonds. The chain can be linear, branched, circular, or combinations thereof. Accordingly, the present invention provides isolated SLSRPs selected from PpSCLI, PpSCL2, PpSCL3, GmSCLI, and their homologs. In preferred embodiments, the SLSRPs are selected from PpSCLI as defined in SEQ ID NO: 2, PpSCL2 as defined in SEQ ID NO: 4, PpSCL3 as defined in SEQ ID NO: 6, GmSCLI as defined in SEQ ID NO: 8, and their counterparts and orthologs. The homologs and orthologs of the amino acid sequences are defined below. The SLSRPs of the present invention are preferably produced by recombinant DNA techniques. For example, a nucleic acid molecule encoding the polypeptide is cloned into an expression vector (as described below), wherein the expression vector is introduced into a host cell (as described below) and the SLSRP is expresses in the host cell. The SLSRP can then be isolated from the cells by an appropriate purification scheme by standard polypeptide purification techniques. For the purposes of the invention, the term "recombinant polynucleotide" refers to a polynucleotide that has been altered, rearranged, or modified by genetic engineering. Examples include any cloned polynucleotide, and polynucleotides linked or linked to heterologous sequences. The term "recombinant" does not refer to alterations in polynucleotides that are the result of natural events, such as spontaneous mutations. As an alternative for recombinant expression, an SLSRP, or its peptide, can be chemically synthesized by standard peptide synthesis techniques. In addition, native SLSRPs can be isolated from cells (eg, Physcomitrella patens and Glycine max cells), for example by an anti-SLSRP antibody, which can be produced by standard techniques using an SLSRP or its fragment. As used herein, the term "environmental stress" refers to sub-optimal conditions associated with salinity, drought, temperature, metal, chemical, pathogenic and oxidative stress, or combinations thereof. In preferred embodiments, the environmental stress may be selected from one or more of the group consisting of salinity, drought, or temperature, or combinations thereof, and in particular, may be selected from one or more of the group consisting of high salinity, low water content, or low temperature. As also used herein, the term "water use efficiency" refers to the amount of organic matter produced by a plant divided by the amount of water used by the plant when it is produced, ie the dry weight of a plant. plant in relation to the use of water in the plant. As used herein, the term "dry weight" refers to any part of the plant outside of water, and includes, for example, carbohydrates, proteins, oils, and mineral nutrients. It should also be understood that as used in the specification and in the claims, "a" or "an" may mean one or more, depending on the context in which it is used. Consequently, for example, the reference to "a cell" can mean that at least one cell can be used. As also used herein, the terms "nucleic acid" and "polynucleotide" refer to linear or branched, single-stranded or double-stranded RNA or DNA, or one of its hybrids. The term also includes RNA / DNA hybrids. These terms also encompass untranslated sequences located at the 3 'and 5' ends of the coding region of the gene: at least about 1000 nucleotides of sequence upstream of the 5 'end of the coding region and at least about 200 nucleotides of downstream sequence of the 3 'end of the coding region of the gene. Less common bases, such as inosine, 5-methylcytosine, 6-methyladenine, hypoxanthine, and others, can also be used for antisense, dsRNA, and ribozyme pairing. For example, it has been shown that polynucleotides containing C-5 propyne analogs of uridine and cytidine bind to RNA with high affinity and that they are powerful antisense inhibitors of gene expression. Other modifications can also be made, such as modification of the phosphodiester backbone, or 2'-hydroxy in the sugar group of RNA ribose. The antisense polynucleotides and the ribozymes may consist entirely of ribonucleotides, or may contain mixed ribonucleotides and deoxyribonucleotides. The polynucleotides of the invention can be produced by any means, such as genomic preparations, cDNA preparations, in vitro synthesis, RT-PCR, and in vitro or in vivo transcription. An "isolated" nucleic acid molecule is one that is substantially separated from other nucleic acid molecules, which are present in the natural source of the nucleic acid (i.e., the coding sequences of other polypeptides). Preferably, an "isolated" nucleic acid is free of some sequences, which naturally flank the nucleic acid (i.e., sequences located at the 5 'and 3' ends of the nucleic acid) in the natural replicon. For example, a cloned nucleic acid is considered isolated. In various embodiments, the isolated SLSRP nucleic acid molecule may contain less than about 5 kb, 4 kb, 3 kb, 2 kb, 1 kb, 0.5 kb, or 0.1 kb of nucleotide sequences that naturally they flank the nucleic acid molecule in the genomic DNA of the cell from which the nucleic acid is derived (e.g., a cell of Physcomitrella patens and Glycine max). A nucleic acid is also considered isolated if it has been altered by human intervention, or located in a site or location that is not its natural site, or if it is introduced into a cell by agroinfection. Moreover, an "isolated" nucleic acid molecule, such as a cDNA molecule, may be free of other cellular material with which it naturally associates, or a culture medium when produced by recombinant techniques, or chemical precursors or other chemical compounds when chemically synthesized. Specifically excluded from the definition of "isolated nucleic acids" are: natural chromosomes (such as chromosome dispersions), artificial chromosome libraries, genomic libraries, and cDNA libraries that exist as an in vitro preparation of nucleic acid or as transfected preparation / host cell transformation, wherein the host cells are in vitro heterogeneous or plated preparations as a heterogeneous population of single colonies. Also specifically excluded are prior libraries wherein a specific nucleic acid represents less than 5% of the amount of nucleic acid insertions in the vector molecules. Preparations of genomic DNA or whole cell RNA are also specifically excluded (including preparations of whole cells mechanically worn or enzymatically digested). Also specifically excluded are preparations of whole cells that are in an in vitro preparation or as a heterogeneous mixture separated by electrophoresis wherein the nucleic acid of the invention has not been separated from the heterologous nucleic acids in the electrophoresis medium (e.g. ., by separation by excision of a single band of the population of heterogeneous bands in agarose gel or nylon blot). A nucleic acid molecule of the present invention, e.g. g., a nucleic acid molecule with a nucleotide sequence of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, SEQ ID NO: 7, or a portion thereof, can be isolated by standard techniques of molecular biology and the sequence information provided herein. For example, SLSRP cDNA from P.patens can be isolated from a P.patens library with all or a portion of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5. In addition, a nucleic acid molecule encompassing all or a portion of the sequence of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7 can be isolated by the chain reaction of polymerase using oligonucleotide primers designed based on this sequence. For example, mRNA can be isolated from plant cells (e.g., by the guanidinium thiocyanate extraction method of Chirgwin et al., 1979, Biochemistry 18: 5294-5299), and cDNA can be prepared by reverse transcriptase ( eg, Moloney MLV reverse transcriptase, available from Gibco / BRL, Bethesda, MD; or AMV reverse transcriptase, available from Seikagaku America, Inc., St. Petersburg, FL). Oligonucleotide primers synthesized by polymerase chain reaction amplification can be designed based on the nucleotide sequence shown in SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7. A nucleic acid molecule of the invention can be amplified by cDNA or, alternatively, genomic DNA, as a template and suitable oligonucleotide primers according to standard PCR amplification techniques. The nucleic acid molecule thus amplified can be cloned into a suitable vector and characterized by DNA sequence analysis. In addition, oligonucleotides corresponding to a SLSR nucleotide sequence can be prepared by standard synthetic techniques, e.g. eg, by means of an automatic DNA synthesizer. In a preferred embodiment, an isolated nucleic acid molecule of the invention comprises the nucleotide sequence shown in SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7. The cDNAs may comprise SLSRP coding sequences, (i.e., the "coding region"), in addition to 5 'untranslated sequences and 3' untranslated sequences. It should be understood that SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7 only comprise the coding region of the nucleotide sequence of SLSRP. Alternatively, the nucleic acid molecules of the present invention can comprise whole genomic fragments isolated from the genomic DNA. The present invention also includes nucleic acids encoding SLSRP that encode SLSRPs as described herein. Preferably, it is a nucleic acid encoding SLSRP encoding PpSCLI as defined in SEQ ID NO: 2, PpSCL2 as defined in SEQ ID NO: 4, PpSCL3 as defined in SEQ ID NO: 6, or GmSCLI as defined in SEQ ID NO: 8. In addition, the nucleic acid molecule of the invention may comprise a portion of the coding region of the sequence shown in SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7, for example, a fragment that can be used as a probe or primer or fragment encoding a biologically active portion of an SLSRP. The nucleotide sequence determined from the cloning of an SLSRP gene from P.patens and G.max allows to generate probes and primers designed for use in the identification and / or cloning of SLSRP homologs in other cell types and organisms, in addition to SLSRP homologs from other mosses and related species. The portion of the coding region can also encode a biologically active fragment of an SLSRP. As used herein, the term "biologically active portion" of an SLSRP is intended to include a portion, e.g. eg, a domain / motive of an SLSRP that participates in the growth of a plant and / or the modulation of stress tolerance in a plant. The tolerance to stress is preferably tolerance to drought, tolerance to frost, or tolerance to salts. For the purposes of the present invention, the term "growth enhancement" of a transgenic plant comprising the expression cassette of SLSRP (or expression vector) refers to at least 10%, 15%, 20%, 25% or 30%, preferably at least 40%, 45%, 50%, 55% or 60%, with greater preference at least 65%, 70%, 75%, 80%, 85%, 90% 95% or greater increase of water use efficiency (WUE) and / or plant dry weight (DW) compared to a non-transgenic or transgenic vector only control. Modulation of stress tolerance refers to at least 10%, 15%, 20%, 25% or 30%, preferably at least 40%, 45%, 50%, 55% or 60%, with greater preference to less 65%, 70%, 75%, 80%, 85%, 90% 95% or greater increase or decrease in stress tolerance of a transgenic plant comprising an SLSRP expression cassette (or expression vector) compared to stress tolerance of a non-transgenic control plant. Methods for quantifying plant growth and stress tolerance are provided at least in Example 7 below. In a preferred embodiment, the biologically active portion of an SLSRP increases the growth of a plant under limited water conditions and / or increases the tolerance of the plant to environmental stress. The biologically active portions of an SLSRP include peptides comprising the amino acid sequence derived from the amino acid sequence of SLSRP, e.g. e.g., an amino acid sequence of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, or the amino acid sequence of a polypeptide identical to an SLSRP, which includes fewer amino acids than a full-length SLSRP or full-length polypeptide that is identical to an SLSRP, and exhibits at least one activity of an SLSRP. In general, biologically active portions (e.g., peptides having, for example, 5, 10, 15, 20, 30, 35, 36, 37, 38, 39, 40, 50, 100, or more amino acids of length) comprise a domain or reason with at least one activity of an SLSRP. In addition, other biologically active portions may be prepared in which other regions of the polypeptide are removed by recombinant techniques and evaluated for one or more of the activities described herein. Preferably, the biologically active portions of an SLSRP include one or more of the selected sequence motifs or their biologically active portions such as the LHR I, LHR II, VHIID, PFYRE, and SAW motifs. The LHR I and II motifs are heptameric repeats of leucine, and the VHIID motif contains I VHIID sequence that is easily recognized in all members of the GRAS family. In the VHIID motif, the P-N-H-D-Q-L residues are absolutely conserved. The spacing between the proline and asparagine residues is identical among all GRAS members, as is the spacing between the histidine, aspartate, glutamine, and leucine residues. The VHIID motif is linked to the terminal C through a conserved sequence called LRITG. The PFYRE motif is not so well preserved at the sequence level (only P is absolutely conserved). In the PFYRE motif, the sequences are mostly collinear, and portions of this region show high degree of sequence similarity among all members of the GRAS family. The SAW motif is characterized by three absolutely conserved pairs of residues: R-E, W-G, and W-W. The W-W pair that is almost at the C terminal shows absolute conservation of the spacing, like the W-G pair; however, the spacing between the pairs W-G and W-W is not conserved. In one embodiment, the present invention provides SLSRP with a scarecrow-like domain comprising the three most conserved motifs: the VHIID motif, the PFYRE motif, and the SAW motif. In another embodiment, the conserved scarecrow-like domain comprises at least one of the following four conserved regions. The present invention includes natural SLSRP and SLSRP analogs and analogs encoded by the nucleic acids of a plant. "Homologs" is defined herein as two nucleic acids or polypeptides with similar, or "identical" nucleotide or amino acid sequences, respectively. Homologs include allelic variants, orthologs, paralogs, agonists, and SLSRP antagonists as defined below. The term "homologue" also encompasses nucleic acid molecules that differ from one of the nucleotide sequences shown in SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7 (and their portions) due to the degeneracy of the genetic code and consequently encodes the same SLSRP as that encoded by the nucleotide sequences shown in SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7 . As used herein, a "natural" SLSRP refers to an amino acid sequence that occurs in nature. Preferably, a natural SLSRP comprises an amino acid sequence of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8. An SLSRP agonist may substantially retain the same, or a subset, of the biological activities of SLSRP. An SLSRP antagonist can inhibit one or more of the activities of the natural form of SLSRP. The nucleic acid molecules corresponding to the natural allelic variants and the analogues, orthologs, and paralogs of a SLSRP cDNA can be isolated based on their identity with the SLSRP nucleic acids of Physcomitrella patens and Glycine max described herein by the SLSRP cDNA, or one of its portions, as a hybridization probe according to standard hybridization techniques under stringent hybridization conditions. In an alternative embodiment, the SLSRP homologs can be identified by combinatorial search libraries of mutants, e.g. g., truncating mutants, of SLSRP for SLSRP agonist or antagonist activity. In one embodiment, a varied library of SLSRP variants is generated by combinatorial mutagenesis at the nucleic acid level and is encoded by a library of varied genes. A varied library of SLSRP variants can be produced, for example, by enzymatic ligation of a mixture of synthetic oligonucleotides with gene sequences such as a degenerate set of possible SLSRP sequences where it is expressed as individual polypeptides, or alternatively, with a set of larger fusion polypeptides (e.g., by phage display) that contain the set of SLSRP sequences. A variety of methods can be used to produce libraries of possible SLSRP homologs from a degenerate sequence of oligonucleotides. The chemical synthesis of a degenerate gene sequence can be carried out in an automatic DNA synthesizer, and then the synthetic gene is ligated into a suitable expression vector. The use of a degenerate set of genes allows to provide, in a mixture, all the sequences that encode the desired set of possible SLSRP sequences. Methods for synthesizing degenerate oligonucleotides are known in the art (see, eg, Narang, 1983, Tetrahedron 39: 3, Itakura et al., 1984, Annu Rev. Biochem 53: 323, Itakura et al. , 1984, Science 198: 1056; Ike et al., 1983, Nucleis Acids Res. 11: 477). In addition, the libraries of the fragments of the coding regions of < j SLSRP can be used to generate a varied population of SLSRP fragments for the search and subsequent selection of homologs of an SLSRP. In one embodiment, a library of sequence coding fragments can be generated by treating a double-stranded PCR fragment of a SLSRP coding sequence with a nuclease under conditions in which only notches are produced approximately once per molecule, denaturing the DNA, renaturing the DNA to form double-stranded DNA, which may include sense / antisense pairs of distinct products with notches, removing single-strand portions of reformed duplexes by treatment with S1 nuclease, and ligating the library of fragments obtained in an expression vector. By this method a library can be derived expression that encodes the N-terminal, the C-terminal, and the internal fragments of various sizes of SLSRP. Various techniques are known in the art for analyzing the gene products of combinatorial libraries formed by point mutations or truncation, and for analyzing cDNA libraries by gene products with a selected property.

These techniques are adapted for the rapid search of gene libraries generated by combinatorial mutagenesis of GAS / SCL homologs. The most widely used techniques, amenable to such analysis, for the analysis of large gene libraries in general includes the cloning of the gene library into replicable expression vectors, to transform suitable cells with the library of obtained vectors, and expresses the combinatorial genes in conditions in which the detection of a desired activity facilitates the isolation of the vector encoding the gene whose product was detected. Recursive assembly mutagenesis (REM), a technique that increases the frequency of functional mutants in libraries, can be used in combination with the search assays to identify the SLSRP homologs (Arkin and Yourvan, 1992, PNAS 89: 781 1-7815; Delgrave et al., 1993, Polipeptide Engineering 6 (3): 327-331). In another embodiment, cell-based assays can be exploited, in order to analyze a varied SLSRP library, by methods well known in the art. The present invention also provides a method to identify a new SLSRP, which comprises a) generating a specific antibody response against an SLSRP, or one of its fragments, as described herein; b) analyzing the possible material of SLSRP with the antibody, where the specific binding of the antibody with the material indicates the presence of a possible new SLSRP; and c) analyze the fixed material in comparison with the known SLSRPs, to determine its novelty. As stated previously, the present invention includes SLSRP and its homologs. To determine the percent sequence identity of two amino acid sequences (e.g., the sequence of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, SEQ ID NO: 8, and one of its mutant forms), the sequences are aligned for optimal comparison purposes (eg, gaps in the sequence of a polypeptide can be introduced for optimal alignment with the other polypeptide or nucleic acid). Then the amino acid residues are compared at the corresponding amino acid positions. When a position in a sequence (e.g., the sequence of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8) is occupied by the same amino acid residue as the corresponding position in the other sequence (e.g., a mutant form of the sequence of SEQ ID NO: 2, SEQ ID NO.4, SEQ ID NO: 6, or SEQ ID NO: 8), then the molecules are identical in that position. The same type of comparison can be made between two nucleic acid sequences. The percentage of sequence identity between the two sequences is a function of the number of identical positions shared by the sequences (i.e., percentage of sequence identity = number of identical positions / total number of positions x 100). Preferably, the isolated amino acid homologs included in the present invention have at least about 50-60%, preferably at least about 60-70%, and more preferably at least about 70-75%, 75-80%, 80 -85%, 85-90%, or 90-95%, and even more preferably at least about 96%, 97%, 98%, 99%, or more identity with a whole amino acid sequence shown in SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8. In yet another embodiment, isolated amino acid homologues included in the present invention have at least about 50-60%, preferably at least about 60-70%, and most preferably preference at least about 70-75%, 75- 80%, 80-85%, 85-90%, or 90-95%, and even more preferably at least about 96%, 97%, 98%, 99%, or more identity with a whole amino acid sequence shown in SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7. In other embodiments, amino acid homologs of SLSRP have sequence identity greater than at least 15 contiguous amino acid residues, more preferably at least 25 contiguous amino acid residues, and more preferably at least 35 contiguous amino acid residues of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8. In another preferred embodiment, an isolated nucleic acid homologs of the invention comprises a nucleotide sequence that is at least about 40-60%, preferably at least about 60-70%, more preferably at least about 70- 75%, 75-80%, 80-85%, 85-90%, or 90-95%, and even more preferably at least about 95%, 96%, 97%, 98%, 99%, or more identity with a nucleotide sequence shown in SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7, or with a portion comprising at least 60 of its consecutive nucleotides. The comparison of preferred sequence length for nucleic acids is at least 75 nucleotides, more preferably at least 100 nucleotides, and even more preferably the total length of the coding region. It is even more preferable that the nucleic acid homologs encode proteins with homology with SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8 at the C terminus which encodes five recognizable motifs as described earlier. It is also preferred that the isolated nucleic acid homologs of the invention encode an SLSRP, or a portion thereof, that is at least 70% identical with an amino acid sequence of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8 and which acts as a modulator of an environmental stress response in a plant. In a more preferred embodiment, modifying the expression of the nucleic acid homologue in a plant increases the growth and tolerance of the plant to environmental stress. For the purposes of the invention, the percentage of sequence identity between two nucleic acid or polypeptide sequences is determined with the Vector NTI 9.0 (PC) software package (InforMax, 7600 Wisconsin Ave., Bethesda, MD 20814). A gap opening tolerance of 15 and a gap extension tolerance of 6.66 are used to determine the percent identity of two nucleic acids. A gap-opening tolerance of 10 and a gap extension tolerance of 0.1 are used to determine the percent identity of two polypeptides. All other parameters are fixed with default values. For the purposes of a multiple alignment (Clustal W algorithm), the gap opening tolerance of 10, and a gap extension tolerance of 0.05 with the blosum62 matrix. It should be understood that for the purpose of determining sequence identity when comparing a DNA sequence with an RNA sequence, a thymidine nucleotide is equivalent to a uracil nucleotide. In another aspect, the invention provides an isolated nucleic acid comprising a polynucleotide that hybridizes the polynucleotide of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7 under stringent conditions. More particularly, an isolated nucleic acid molecule of the invention is at least 15 nucleotides in length and hybridizes under stringent conditions to the nucleic acid molecule comprising a nucleotide sequence of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ] Q ID NO: 7. In other embodiments, the nucleic acid is at least 30, 50, 100, 250, or more nucleotides in length. Preferably, a homolog of an isolated nucleic acid of the invention comprises a nucleotide sequence that hybridizes under conditions of high stringency to the nucleotide sequences shown in SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5 , or SEQ ID NO: 7, and it works as a modulator of tolerance to stress in a plant. In another preferred embodiment, overexpression of the nucleic acid homolog isolated in a plant increases the growth of a plant and tolerance to environmental stress. As used herein for hybridization to DNA in a DNA blot, the term "stringent conditions" refers to hybridization overnight at 60 ° C in 10X Denhart solution, 6X SSC, 0.5% SDS, and 100 μg / ml of denatured salmon sperm DNA. The blots are washed in sequence at 62 ° C for 30 minutes each time in 3X SSC / 0.1% SDS, followed by 1X SSC / 0.1% SDS, and finally 0.1X SSC / 0.1% SDS. In another embodiment, "stringent conditions" refers to hybridization in a solution 6X SSC solution at 65 ° C. As also used herein, "very stringent conditions" refers to overnight hybridization at65 ° C in 10X Denhart solution, 6X SSC, 0.5% SDS, and 100 μg / ml salmon sperm DNA denatured. The blots are washed in sequence at 65 ° C for 30 minutes each time in 3X SSC / 0.1% SDS, followed by 1X SSC / 0.1% SDS, and finally 0.1X SSC / 0.1% SDS. Methods for hybridizations of nucleic acids are described in Meinkoth and Wahl, 1984, Anal. Biochem. 138: 267-284; Current Protocols in Molecular Biology, Chapter 2, Ausubel et al. Eds., Greene Publishing and Wiley-lnterscience, New York, 1995; and Tijssen, 1993, Laboratory Techniques in Biochemistry and Molecular Biology: Hybridization with Probes of Nucleic Acids, Part I, Chapter 2, Elsevier, New York, 1993. Preferably, an isolated nucleic acid molecule of the invention that hybridizes in rigorous or very stringent conditions to a sequence of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7 corresponds to a natural nucleic acid molecule. As used herein, a "natural" nucleic acid molecule refers to an RNA or DNA molecule with a nucleotide sequence that is found in nature (eg, that encodes a natural polypeptide). In another embodiment, the nucleic acid encodes a natural SLSRP from Physcomitrella patens. By the methods described above, and others known to those skilled in the art, one of ordinary skill in the art can isolate homologues of the SLSRP comprising the amino acid sequences shown in SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO. : 6, or SEQ ID NO: 8. A subset of these homologs are allelic variants. As used herein, the term "allelic variant" refers to a nucleotide sequence that contains polymorphisms that lead to changes in the amino acid sequences of an SLSRP and that exist in a natural population (e.g., a species or plant variety). Said natural allelic variations generally result in 1-5% variance in an SLSRP nucleic acid. Allelic variants can be identified by determining the sequence of the nucleic acids of interest in several different plants, which can be easily performed by hybridization probes in order to identify the same genetic site of SLSRP in those plants. All these variations of nucleic acids and the resulting polymorphisms or amino acid variations in an SLSRP that are a consequence of the natural allelic variation and that do not alter the functional activity of an SLSRP, are intended to be encompassed in the invention. In addition, nucleic acid molecules encoding SLSRP from the same species or other species such as analogs, orthologs, and SLSRP paralogs are intended to be included in the scope of the present invention. As used in the present, the term "analogues" refers to two nucleic acids with the same or similar function, but which have evolved separately in unrelated organisms. As used herein, the term "orthologs" refers to two nucleic acids of different species, but which have evolved from a common ancestral gene by speciation. Normally, orthologs encode polypeptides with the same or similar functions. As also used herein, the term "paralogs" refers to two nucleic acids related by duplication in a genome. Paralogs usually have different functions, but these functions may be related (Tatusov et al., 1997, Science 278 (5338): 631-637). Analogs, orthologs, and paralogs of a natural SLSRP may differ from natural SLSRP by post-translational modifications, by differences in amino acid sequence, or by both. Post-translational modifications include the chemical derivation in vivo and in vitro of polypeptides, e.g. eg, acetylation, carboxylation, phosphorylation, or glycosylation, and such modifications may occur during the synthesis or processing of polypeptides or after treatment with isolated modifying enzymes. In particular, the orthologs of the invention generally exhibit at least 80-85%, more preferably, 85-90% or 90-95%, and more preferably still 95%, 96%, 97%, 98%, or even 99% identity, or 100% sequence identity, with all or part of a natural SLSRP amino acid sequence, and exhibits a function similar to an SLSRP. Preferably, an SLSRP ortholog increases growth and stress tolerance of a plant. In addition to the natural variants of an SLSRP sequence that may exist in the population, the skilled artisan will also appreciate that changes can be introduced by mutation in a nucleotide sequence of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO. : 5, or SEQ ID NO: 7, which leads to changes in the amino acid sequence of the encoded SLSRP, without altering the functional activity of SLSRP. For example, nucleotide substitutions leading to amino acid substitutions in "non-essential" amino acid residues can be made in a sequence of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7 A "nonessential" amino acid residue is a residue that can be altered from the wild type sequence of an SLSRP without altering the activity of said SLSRP, while an "essential" amino acid residue is required for SLSRP activity. Other amino acid residues, however, (eg, those not conserved or only semi-preserved in the domain with SLSRP activity) may not be essential for the activity and the consequence may be susceptible to alteration without altering the activity of SLSRP.

Accordingly, another aspect of the invention relates to the nucleic acid molecule encoding SLSRP that contains changes in amino acid residues not essential for SLSRP activity. Said SLSRP differ in amino acid sequence with respect to a sequence contained in SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8, although it retains at least one of the SLSRP activities described in the present. In one embodiment, the isolated nucleic acid molecule comprises a nucleotide sequence encoding a polypeptide, wherein the polypeptide comprises an amino acid sequence with at least about 50% identity to an amino acid sequence of SEQ ID NO: 2 , SEQ ID NO: 4, SEQ ID NO.6, or SEQ ID NO: 8. Preferably, the polypeptide encoded by the nucleic acid molecule has at least about 50-60% identity with the sequence of SEQ ID NO: 2, more preferably at least about 60-70% identity with the sequence of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8, with even greater preference at least approximately 70-75%, 75-80%, 80-85%, 85-90%, or 90-95% identity with the sequence of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8, and even more preferably at least about 96%, 97%, 98%, or 99% identity with the sequence of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8. Preferred SLSRP homologs of the present invention preferably participate in the growth of a plant and the stress tolerance response, or more particularly, participate in the transcription of a polypeptide that mediates the growth of a plant and the response of tolerance to stress, and / or act as a transcription factor. An isolated nucleic acid molecule encoding an SLSRP with sequence identity with a polypeptide sequence of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8 can be created by introducing a or more substitutions, additions or deletions of nucleotides in a nucleotide sequence of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7, such that one or more substitutions, additions, or deletions of amino acids in the encoded polypeptide. Mutations can be introduced into one of the sequences of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7 by standard techniques, such as site-directed mutagenesis and PCR-mediated mutagenesis. Preferably, conservative amino acid substitutions are made in one or more predicted residues of non-essential amino acids. A "conservative amino acid substitution" is one in which the amino acid residue is replaced by an amino acid residue with a similar side chain. Families with amino acid residues with similar side chains have been defined in the art. These families include amino acids with basic side chains (eg, lysine, arginine, histidine), acid side chains (eg, aspartic acid, glutamic acid), uncharged polar side chains (eg, glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine), non-polar side chains (eg, alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan), side chains with beta branching (eg. , threonine, valine, isoleucine), and aromatic side chains (eg, tyrosine, phenylalanine, tryptophan, histidine). Accordingly, a predicted non-essential amino acid residue in a SLSRP is preferably replaced by another amino acid residue from the same family of side chains. Alternatively, in another embodiment, mutations can be introduced by bracketing over all or parts of an SLSRP coding sequence, such as by saturation mutagenesis, and the resulting mutants can be analyzed for the SLSRP activity described. in the present, in order to identify the mutants that retain SLSRP activity. After the mutagenesis of the sequence of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7, the encoded polypeptide can be expressed by recombination and the activity of the polypeptide can be determined by growth analysis and stress tolerance of a plant expressing the polypeptide, as described in Example 7. In addition, optimized SLSRP nucleic acids can be created. Preferably, an optimized SLSRP nucleic acid encodes an SLSRP that binds to a phosphate group and / or modulates a plant's tolerance to environmental stress, and more preferably increases a plant's growth and tolerance to environmental stress after its overexpression in the plant. As used herein, "optimized" refers to a nucleic acid engineered to increase its expression in a particular plant or animal. To provide optimized nucleic acids for plant SLSRPs, the DNA sequence of a gene can be modified in order to: 1) understand codons preferred by plant genes with high expression; 2) to understand a higher content of A + T of nucleotide base composition compared to that substantially found in plants; 3) forming a plant initiation sequence; or 4) eliminate sequences that cause destabilization, inadequate polyadenylation, degradation and termination of RNA, or that form hairpins of secondary structures or RNA splice sites. The highest expression of SLSRP nucleic acids in plants can be achieved by using the distribution frequency of codon usage in plants in general or in a particular plant. Methods for optimizing the expression of nucleic acids in plants can be found in EPA 0359472; EPA 0385962; PCT Application No. WO 91/16432; U.S. Patent No. 5,380,831; U.S. Patent No. 5,436,391; Perlack et al., 1991, Proc. Nati Acad. Sci. USA 88: 3324-3328; and Murray et al., 1989, Nucleic Acids Res. 17: 477-498. A SLSRP nucleic acid can be optimized such that its frequency of codon usage distribution does not deviate, preferably, more than 25% from the genes of plants with high expression and, more preferably, no more than approximately 10%. In addition, the percentage of the G + C content of the degenerate third base is considered (monocots seem to prefer G + C in this position, unlike dicotyledons). It is also recognized that nucleotide XCG (where X is A, T, C, or G) is the codon of least preference in dicotyledons, while codon XTA is avoided in monocotyledons and dicotyledons. The optimized nucleic acids of SLSRP of the present invention also preferably have GC and TA doublet avoidance indices very close to those of the chosen host plant. More preferably these indices deviate from those of the host by no more than about 10-15%. In addition to the nucleic acid molecules encoding the SLSRPs described above, another aspect of the present invention relates to isolated nucleic acid molecules that are antisense to them. Antisense polynucleotides appear to inhibit gene expression of a target polynucleotide by specific binding to the target polynucleotide and interfere with transcription, splicing, transport, translation, and / or stability of the white polynucleotide. Methods are described in the prior art for directing the antisense polynucleotide to the DNA of the chromosome, to a primary RNA transcript, or to a processed mRNA. Preferably, the target regions include splice sites, translation initiation codons, translation termination codons, and other sequences within the open reading frame. The term "antisense" for the purposes of the invention, refers to a nucleic acid comprising a polynucleotide with sufficient complementarity with all or a portion of a gene, primary transcript, or processed mRNA, to interfere with the expression of the gene endogenous. The "complementary" 5 polynucleotides are those capable of matching their bases according to the standard Watson-Crick complementarity rules. Specifically, the purines are paired by the bases with the pyrimidines, to form a combination of guanine paired with cytosine (G: C) and adenine paired with thymine (A: T) in the case of DNA, or adenine paired with uracil (A : U) in the case of RNA. It is understood that two or polynucleotides can hybridize to each other even if they do not have complete complementarity between them, provided that each has at least one region that is substantially complementary to the other. The term "antisense nucleic acid" includes single-stranded RNA and double-stranded DNA expression cassettes that can be transcribed to obtain an antisense RNA. "Active" antisense nucleic acids are antisense RNA molecules capable of selectively hybridizing with a primary transcript or mRNA encoding a polypeptide with at least 80% sequence identity with the polypeptide of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8. The antisense nucleic acid can be complementary to a coding strand of SLSRP, or only to a portion thereof. In one embodiment, an antisense nucleic acid molecule is antisense to a "coding region" of the coding strand of a nucleotide sequence encoding an SLSRP. The term "coding region" refers to the region of the nucleotide sequence that comprises codons that are translated into amino acid residues. In another embodiment, the antisense nucleic acid molecule is antisense to a "non-coding region" of the coding strand of a nucleotide sequence encoding an SLSRP. The term "non-coding region" refers to 5 'and 3' sequences that flank the coding region untranslated to amino acids (ie, also called 5 'and 3' untranslated regions). The antisense nucleic acid molecule may be complementary to the whole mRNA coding region of SLSRP, but more preferably it is an oligonucleotide that is antisense to only a portion of the coding or non-coding region of the SLSRP mRNA. For example, the antisense oligonucleotide can be complementary to the region surrounding the translation start site of the SLSRP mRNA. An antisense oligonucleotide can have, for example, about 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 nucleotides in length. In general, the antisense molecules of the present invention comprise an RNA with 60-100% sequence identity with at least 14 consecutive nucleotides of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID N0.7, or a polynucleotide encoding polypeptides of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8. Preferably, the sequence identity will be at least 70%, more preferably at least 75%, 80%, 85%, 90%, 95%, or 98%, and even more preferably 99%. The antisense nucleic acid molecules of the invention are generally administered to a cell or generated in situ, such that they hybridize or bind to the cellular mRNA and / or the genomic DNA encoding an SLSRP and thus inhibit the expression of the polypeptide, p. eg, by inhibiting transcription and / or translation. Hybridization may be by conventional nucleotide complementarity to form a stable doublet, or, for example, in the case of an antisense nucleic acid molecule that binds to DNA doublets, through specific interactions in the main cavity of the double helix. The antisense molecule can be modified such that it specifically binds to a receptor or an antigen expressed on a selected cell surface, e.g. eg, by binding the antisense nucleic acid molecule to a peptide or an antibody that binds to a cell surface receptor or antigen. The antisense nucleic acid molecule can also be delivered to cells by the vectors described herein. To achieve sufficient intracellular concentrations of antisense molecules, vector constructs in which the antisense nucleic acid molecule is placed under the control of a strong prokaryotic, viral, or eukaryotic (including plant) promoter are preferred. As an alternative to antisense polynucleotides, ribozymes, sense polynucleotides, or double-stranded RNA (dsRNA) can be used to reduce the expression of an SLSRP polypeptide. As used herein, the term "ribozyme" refers to an RNA-based catalytic enzyme with ribonuclease activity, which is capable of cleaving a single-stranded nucleic acid, eg, a mRNA, with which it has a complementary region. Ribozymes (eg, hammerhead ribozymes described in Haselhoff and Gerlach, 1988, Nature 334: 585-591) can be used to catalytically cleave transcripts of mRNA from can SLSRP and thus inhibit mRNA translation of SLSRP. A ribozyme with specificity can be designed by a nucleic acid encoding SLSRP, based on the nucleotide sequence of an SLSRP cDNA, as described herein (ie, SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7) or on the basis of an isolated heterologous sequence according to methods taught in the present invention. For example, an RNA derivative of Tetrahymena L-19 IVS can be constructed in which the nucleotide sequence of the active site is complementary to the nucleotide sequence cleaved in a mRNA that encodes SLSRP. See, p. eg, U.S. Patents Nos. 4,987,071 and 5,116,742 to Cech et al. Alternatively, SLSRP mRNA can be used to select a catalytic RNA with specific ribonuclease activity from a pool of RNA molecules. See, p. eg, Bartel and Szostak, 1993, Science 261: 1411-1418. In preferred embodiments, the ribozyme contains a portion with at least 7, 8, 9, 10, 12, 14, 16, 18, or 20 nucleotides, and most preferably 7 or 8 nucleotides, with 100% complementarity with a portion of the white RNA. Methods for preparing ribozymes are known to those skilled in the art. See, p. eg, United States Patent No. 6,025,167; 5,773,260; and 5,496,698. The term "dsRNA," as used herein, refers to RNA hybrids comprising two strands of RNA. The dsRNAs can be linear or circular in structure. In a preferred embodiment, the dsRNA is specific for a polynucleotide encoding the polypeptide of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8, or a polypeptide with minus 80% sequence identity with a polypeptide of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8. The hybridized RNAs can be substantially or completely complementary. By "substantially complementary" it is meant that when two hybridized RNAs are optimally aligned by the BLAST program as described above, the hybridized portions are at least 95% complementary. Preferably, the dsRNA will be at least 100 base pairs in length. In general, the annealed RNAs will be of identical length, without leftovers at the 5 'or 3' ends and without gaps. However, dsRNAs can be used with 5 'or 3' overs of up to 100 nucleotides in the methods of the invention. The dsRNAs may comprise ribonucleotides, ribonucleotide analogs such as 2'-0-methylribosyl residues, or combinations thereof. See, p. eg, United States Patents Nos. 4,130,641 and 4,024,222. A dsRNA of polyriboinosinic acid: polyribocytidylic acid is disclosed in U.S. Patent No. 4,283,393. The methods for preparing and using dsRNA are known in the art. One method comprises the simultaneous transcription of two complementary strands of DNA, in vivo, or a single reaction mixture in vitro. See, p. e.g., U.S. Patent No. 5,795,715. In one embodiment, dsRNA can be introduced into a plant or plant cell directly by standard transformation methods. Alternatively, dsRNA can be expressed in a plant cell by transcribing two complementary RNAs. Other methods for inhibiting the expression of endogenous genes, such as triple helix formation (Moser et al., 1987, Science 238: 645-650 and Cooney et al., 1988, Science 241: 456-459) and cosupression (Napoli et al., 1990, The Plant Cell 2: 279-289) are known in the art. Full length and partial cDNAs have been used for the co-suppression of endogenous plant genes. See, p. eg, U.S. Patents Nos. 4,801, 340, 5,034,323, 5,231, 020, and 5,283,184; Van der Kroll et al., 1990, The Plant Cell 2: 291-299; Smith et al., 1990, Mol. Gen. Genetics 224: 477-481; and Napoli et al., 1990, The Plant Cell 2: 279-289. For sense deletion, it is believed that the introduction of a sense polynucleotide blocks the transcription of the corresponding target gene. The sense polynucleotide will have at least 65% sequence identity with the target plant gene or RNA. Preferably, the identity percentage is at least 80%, 90%, 95%, or greater. The inserted sense polynucleotide does not need to have the full length relative to the target gene or transcript. Preferably, the sense polynucleotide will have at least 65% sequence identity with at least 100 consecutive nucleotides of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7. The identity regions may comprise introns and / or exons and untranslated regions. The introduced sense polynucleotide may be present in the plant cell transiently, or it may be stably integrated into a plant chromosome or an extrachromosomal replicon. Alternatively, the expression of the SLSRP gene can be inhibited by directing the nucleotide sequences complementary to the regulatory region of a SLSRP nucleotide sequence (eg, an SLSRP promoter and / or enhancer) to form triple helical structures that prevent transcription of an SLSRP gene in target cells. See in general, Helene, 1991, Anticancer Drug Des. 6 (6): 569-84; Helene et al., 1992, Ann. N.Y. Acad. Sci. 660: 27-36; and Maher, 1992, Bioassays 14 (12): 807-15. In addition to the SLSRP nucleic acids and polypeptides described above, the present invention encompasses these nucleic acids and polypeptides attached to a residue. These residues include, without limitation, detection residues, hybridization residues, purification residues, provision residues, reaction residues, fixing residues, and the like. A typical group of nucleic acids with attached residues are the probes and the primers. In general, probes and primers comprise a substantially isolated oligonucleotide. The oligonucleotide generally comprises a nucleotide sequence region that hybridizes under stringent conditions to at least about 12, preferably about 25, more preferably about 40, 50, or 75 consecutive nucleotides of a strand with sense of the sequence set forth in SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7; an antisense sequence of the sequence set forth in SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7, or their natural mutants. Primers based on a nucleotide sequence of SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5, or SEQ ID NO: 7 can be used in PCR reactions to clone SLSRP homologues. Probes based on the nucleotide sequences of SLSRP can be used to detect transcripts or genomic sequences encoding same or substantially identical polypeptides. In preferred embodiments, the probe also comprises a group of attached label, e.g. ex. the label group can be a radioisotope, a fluorescent compound, an enzyme, or an enzyme cofactor. Such probes can be used as part of a genomic marker test kit to identify cells expressing an SLSRP, for example by measuring a level of an SLSRP-encoding nucleic acid, in a sample of cells, e.g. eg, to detect SLSRP mRNA levels or to determine whether a SLSRP genomic gene has been mutated or deleted. In particular, a useful method to ensure the level of transcription of the gene (an indicator of the amount of mRNA available for translation of the gene product) is to perform Northern blotting (for reference see, for example, Ausubel et al., 1988, Current Protocols in Molecular Biology, Wiley: New York). Northern blot information demonstrates at least in part the degree of transcription of the transformed gene. Total cellular RNA can be prepared from cells, tissues or organs by various methods, all well known in the art, such as those described in Bormann et al., 1992, Mol. Microbiol. 6: 317-326. To ensure the presence or relative amount of a polypeptide translated from this mRNA, standard techniques, such as Western blot, can be employed. These techniques are well known to those skilled in the art. (See, for example, Ausubel et al., 1988, Current Protocols in Molecular Biology, Wiley: New York). The invention also provides an isolated recombinant expression vector comprising a SLSRP nucleic acid as described above, wherein expression of the vector in a host cell results in increased growth and tolerance to environmental stress, compared to a variety wild type of the host cell. As used herein, the term "vector" refers to a nucleic acid molecule capable of transporting another nucleic acid to which it has been linked. One type of vector is a "plasmid," which refers to a loop of double-stranded circular DNA in which additional segments of DNA can be ligated. Another type of vector is a viral vector, where additional segments of DNA can be ligated into the viral genome. Certain vectors are capable of autonomous replication in a host cell to which they are introduced (eg, bacterial vectors with bacterial origin of replication and mammalian episomal vectors). Other vectors (e.g., non-episonal mammalian vectors) are integrated into the host cell genome upon introduction into the host cell, and consequently are replicated along with the host genome. In addition certain vectors are capable of directing the expression of the genes to which they are operatively linked. Said vectors are referred to herein as "expression vectors." In general, expression vectors of utility in recombinant DNA techniques are often in the form of plasmids. In the present specification, "plasmid" and "vector" can be used interchangeably, since the plasmid is the most common form of vector use. However, the invention is also intended to include other forms of expression vectors, such as viral vectors (e.g., replication defective retroviruses, adenoviruses, and adeno-associated viruses), which have equivalent functions. The recombinant expression vectors of the invention comprise a nucleic acid of the invention in a form suitable for the expression of the nucleic acid in a host cell, which means that the recombinant expression vector includes one or more regulatory sequences selected based on the host cells that are used for expression, which are operably linked to the nucleic acid sequence to be expressed. As used herein with respect to a recombinant expression vector, "operably linked" is intended to mean that the nucleotide sequence of interest is linked to the regulatory sequence (s) in a manner that allows the expression of the nucleotide sequence (e.g., in an in vitro transcription / translation system or in a host cell when the vector is introduced into the host cell). The term "regulatory sequence" is intended to include promoters, enhancers, and other elements of expression control (eg, polyadenylation signals). Such regulatory sequences are described, for example, in Goeddel, 1990, Gene Expression Technology: Methods in Enzymology 185, Academic Press, San Diego, CA and Gruber and Crosby, in: Methods in Plant Molecular Biology and Biotechnology, eds. Glick and Thompson, Chapter 7, 89-108, CRC Press: Boca Raton, Florida, including references. Regulatory sequences include those that direct the constitutive expression of a nucleotide sequence in many types of host cells and those that direct the expression of the nucleotide sequence only in certain host cells or under certain conditions. Those skilled in the art will appreciate that the design of the expression vector may depend on such factors as the choice of the host cell that it is desired to transform the level of expression of the desired polypeptide, etc. The expression vector of the invention can be introduced into host cells, so as to produce polypeptides or peptides, including polypeptides or fusion peptides, encoded by nucleic acids as described herein (eg, SLSRP, mutant forms of SLSRP , fusion polypeptides, etc.). The recombinant expression vectors of the invention can be designed for the expression of SLSRP in prokaryotic or eukaryotic cells. For example, the SLSRP genes can be expressed in bacterial cells such as C. glutamicum, insect cells (with baculovirus expression vector), yeast and other fungal cells (See Romans et al., 1992, Foreign gene expression in yeast: a review, Yeast 8: 423-488; Van den Hondel et al. , 1991, Heterologous gene expression in filamentous fungi, in: More Gene Manipulations in Fungi, Bennet and Lasure, eds., P. ^ 396-428: Academic Press: San Diego, and Van den Hondel and Punt, 1991, Gene transfer systems and vector development for filamentous fungi, in: Applied Molecular Genetics of Fungi, Peberdy et al., eds., pp. 1-28, Cambridge University Press: Cambridge), algae (Falciatore et al., 1999, Marine Biotechnology 1 (3 ): 239-251), ciliates of the types: Holotrichia, Peritrichia, Spirotrichia, Suctoria, Tetrahymena, Paramecium, Colpidium, IQ Glaucoma, Platyophrya, Potomacus, Pseudocohnilembus, Euplotes, Engelmaniella, and Stylonychia, especially of the genus Stylonychia lemnae with vectors following a transformation method as described in the PCT application No. WO 98/01572, and multicellular plant cells (See Schmidt and Willmitzer, 1988, High efficiency Agrobacterium tumefaciens-med \ a \ ed transformation of Arabidopsis thaliana leaf and cotyledon explants, Plant Cell Rep. 583-586; Plant Molecular Biology and Biotechnology, C Press, Boca Raton, Florida, chapter 6/7, S, 71-1 19, 1993; White et al., 1993, Techniques for Gene Transfer, in: Transgenic Plants, Vol. 1, Engineering and Utilization, eds. Kung und R. Wu, 128 ^ 43, Academic Press; Potrykus, 1991, Annu. Rev. Plant Physiol. Plant Molec. Biol. 42: 205-225 and its cited references), or mammalian cells. Suitable host cells are analyzed in Goeddel, 1990, Gene Expression Technology: Methods in Enzymology 185, Academic Press: San Diego, CA. Alternatively, the recombinant expression vector can be transcribed and translated in vitro, for example by regulatory sequences of T7 promoter and T7 polymerase. Expression of polypeptides in prokaryotes is often carried out with vectors containing constitutive or inducible promoters that direct the expression of fusion or non-fusion polypeptides. The fusion vectors add a certain amount of amino acids to a coded polypeptide, generally to the amino terminus of the recombinant polypeptide, but also to the C-terminus or to fuse with the appropriate regions of the polypeptides. Said fusion vectors generally serve three purposes: 1) increasing the expression of a recombinant polypeptide; 2) increase the solubility of a recombinant polypeptide; and 3) contribute to the purification of a recombinant polypeptide by acting as a ligand in an affinity purification. Often in fusion expression vectors, a proteolytic cleavage site is introduced at the junction of the fusion residue and the recombinant polypeptide to allow separation of the recombinant polypeptide from the fusion residue after purification of the fusion polypeptide. Said enzymes, and their cognate recognition sequences, include Factor Xa, thrombin, and enterokinase. Typical fusion expression vectors include pGEX (Pharmacia Biotech Inc, Smith and Johnson, 1988, Gene 67: 31 ^ 0), pMAL (New England Biolabs, Beverly, MA), and pRIT5 (Pharmacia, Piscataway, NJ) which fuse glutathione-S-transferase (GST), maltose E polypeptide, or polypeptide A, respectively, to the white recombinant polypeptide. In one embodiment, the SLSRP coding sequence is cloned into a pGEX expression vector to create a vector J O encoding a fusion polypeptide comprising, from the N-terminus to the C-terminus, the GST-thrombin cleavage site X polypeptide. The fusion polypeptide can be purified by affinity chromatography with glutathione-agarose resin. Recombinant SLSRP not fused with GST can be recovered by cleavage of the fusion polypeptide with thrombin. 15 Examples of suitable non-fusion inducible expression vectors E. coli include pTrc (Amann et al., 1988, Gene 69: 301-315) and pET 1 1 d (Studier et al., 1990, Gene Expression Technology: Methods in Enzymology 185: 60-89, Academic Press, San Diego, CA). The expression of the target gene from the pTrc vector depends on the transcription of the RNA polymerase of the host by a hybrid promoter of the trp-lac fusion. The expression of the target gene from the pET 1 1 d vector depends on the transcription from the T7 gn10-lac fusion promoter mediated by a co-expressed viral RNA polymerase (T7 gn1). This viral polymerase is provided by the host strains BL21 (DE3) or HMS174 (DE3) from a resident profago? harboring a T7 gn1 gene under the control of transcription of the lacUV 5 promoter. One strategy to maximize expression of the recombinant polypeptide is to express the polypeptide in a host bacterium with impaired ability to proteolytically cleave the recombinant polypeptide (Gottesman, 1990, Gene Expression Technology: Methods in Enzymology 185: 1 19-28, Academic Press, San Diego, CA). Another strategy is to alter the sequence of the nucleic acid to be inserted into an expression vector such that the individual codons for each amino acid are those preferably used in the bacterium chosen for expression, such as C. glutamicum (Wada et al. ., 1992, Nucleic Acids Res. 20:21 1 1-21 18). Said alteration of nucleic acid sequences of the invention can be carried out by standard DNA synthesis techniques. In another embodiment, the SLSRP expression vector is a yeast expression vector. Examples of expression vectors in yeast S. cerevisiae include pYepSed (Baldari, et al., 1987, EMBO J. 6: 229-234), pMFa (Kurjan and Herskowitz, 1982, Cell 30: 933-943), pJRY88 (Schultz et al., 1987, Gene 54: 1 13-123), and pYES2 (Invitrogen Corporation, San Diego, CA). The vectors and the. methods for the construction of suitable vectors for use in other fungi, such as filamentous fungi, include those detailed in: Van den Hondel and Punt, 1991, "Gene transfer systems and vector development for filamentous fungi," in: Applied Molecular Genetics of Fungi, Peberdy, et al., eds., p. 1-28, Cambridge University Press: Cambridge. In a preferred embodiment of the present invention, the SLSRP are expressed in plants and plant cells such as unicellular plant cells (eg algae) (See Falciatore et al., 1999, Marine Biotechnology 1 (3): 239-251 and references therein) and plant cells from higher plants ( eg, spermatophytes, such as cereal plants). An SLSRP can be "introduced" in a plant cell by any means, such as transfection, transformation or transduction, electroporation, particle bombardment, agroinfection, and the like. A transformation method known to those skilled in the art consists of immersing a flowering plant in a solution of Agrobacteria, wherein the Agrobacteria contains the nucleic acid of SLSRP, followed by the culture of the transformed gametes. Other suitable methods for transforming or transfecting host cells including plant cells can be found in Sambrook, et al., 1989, Molecular Cloning: A Laboratory Manual, latest ed., Cold Spring Harbor Laboratory, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY and other laboratory manuals such as Methods in Molecular Biology, 1995, Vol. 44, Agrobacterium protocols, ed: 5 Gartland and Davey, Humana Press, Totowa, New Jersey. Since tolerance to biotic and abiotic stress is a general trait that is desired to be inherited in a wide variety of plants such as corn, wheat, rye, oats, triticum, rice, barley, soybeans, peanuts, cotton, rape seed , cañola, cassava, pepper, sunflower, tagetes, solanaceous plants such as potatoes, tobacco, eggplant, tomato, species of 0 Vicia, peas, alfalfa, shrub plants (coffee, cocoa, tea), Salix species, trees (oil palm, coconut), perennial grasses, and forage grains, These cereal plants are also white plants preferably for genetic engineering as another embodiment of the present invention. Forage grains include, without limitation, Wheatgrass, Canarygrass, Bromegrass, Wild Grass 5, Bluegrass, Orchardgrass, Alfalfa, Salfoin, Trefoil Birdsfoot, Alsike Clover, Red Clover, and Sweet Clover. In an embodiment of the present invention, the transfection of an SLSRP in a plant is achieved by gene transfer mediated by Agrobacterium. The plant transformation mediated by Agrobacterium can be carried out, for example, with the strains GV3101 (pMP90) (Koncz and Schell, 1986, Mol.Gen.Genet. 204: 383-396) or LBA4404 (Clontech) of Agrobacterium tumefaciens. The transformation can be done by standard transformation and regeneration techniques (Deblaere et al., 1994, Nucí Acids, Res. 13: 4777-4788; Gelvin et al., 1995, Plant Molecular Biology Manual, 2nd Ed. - Dordrecht: Kluwer Academic Publ., -in Sect., Ringbuc Zentrale Signatur: BT1 1-P ISBN 0-7923-2731-4; Glick et al., 1993, Methods in Plant Molecular Biology and Biotechnology, Boca Raton: CRC Press, 360 S., ISBN 0-8493-5164-2). For example, rape can be transformed by cotyledon or hypocotyledon transformation (Moloney et al., 1989, Plant Cell Report 8: 238-242; De Block et al., 1989, Plant Physiol. 91: 694-701) . The use of antibiotics for the selection of Agrobacterium and plants depends on the binary vector and the strain of Agrobacterium used for the transformation. The selection of rape is normally carried out with kanamycin as a plant selection marker. Gene transfer to linen mediated by Agrobacterium can be performed, for example, by a technique described by Mlynarova et al., 1994, Plant Cell Report 13: 282-285. In addition, soybean bean processing can be performed for example with a technique described in European Patent No. 0424 047, US Patent No. 5,322,783, European Patent No. 0397 687, US Pat. United States No. 5,376.43, or United States Patent No. 5, 169,770. Corn transformation can be achieved by particle bombardment, DNA uptake mediated by polyethylene glycol, or by the silicon carbide fiber technique. ( for example, Freeling and Walbot, 1993, "The maize handbook" Springer Verlag: NY, ISBN 3-540-97826-7). A specific example of corn transformation is found in U.S. Patent No. 5,990,387, and a specific example of wheat transformation is found in PCT Application No. WO 93/07256. In accordance with the present invention, the introduced SLSRP can be maintained in the plant cell in stable form if it is incorporated into a non-chromosomal autonomous replicon or integrated into the plant chromosomes. Alternatively, the introduced SLSRP may be present in a non-replicating non-chromosomal autonomous vector and may be expressed transiently or be transiently active.

In one embodiment, a recombinant homologous microorganism can be created wherein SLSRP is integrated into a chromosome, a vector is prepared that contains at least a portion of an SLSRP into which a deletion, addition, or substitution has been introduced for alter, p. ex. , will functionally alter the SLSRP gene. Preferably, the SLSRPs are SLSRP genes of Physcomitrella patens and Glycine max, but may be homologs of a related plant or even of a mammalian, yeast, or insect source. In one embodiment, the vector is designed such that after homologous recombination, the endogenous SLSRP gene is functionally disrupted (i.e., it no longer encodes a functional polypeptide, it is also referred to as a knock-out vector). Alternatively, the vector can be designed such that upon homologous recombination, the endogenous SLSRP gene is mutated or otherwise altered but still encodes a functional polypeptide (eg, the upstream regulatory region can be altered to thereby alter the expression of endogenous SLSRP). To create a point mutation by homologous recombination, DNA-RNA hybrids can be used in a technique called chimeraplasty (Cole-Strauss et al., 1999, Nucleic Acid Research 27 (5): 1323-1330 and Kmiec, 1999, Gene Therapy American Scientist 87 (3): 240-247). Homologous recombination procedures in Physcomitrella patens are also well known in the art and are contemplated for use herein. While in the homologous recombination vector, the altered portion of the SLSRP gene is flanked at its 5 'and 3' ends by an additional SLSRP nucleic acid molecule to allow homologous recombination to take place between the exogenous transported SLSRP gene. by the vector and an endogenous SLSRP gene, in a microorganism or plant. The additional flanking nucleic acid molecule of SLSRP has sufficient length for the success of the homologous recombination with the endogenous gene. In general, several hundred base pairs up to kilobases of flanking DNA (at the 5 'and 3' ends) are included in the vector (See, e.g., Thomas and Capecchi, 1987, Cell 51: 503 for a description of a homologous recombination vector or Strepp et al., 1998, PNAS, 95 (8): 4368-4373 for cDNA-based recombination in Physcomitrella patens and Glycine max). The vector is introduced into a microorganism or plant cell (e.g., through DNA mediated by polyethylene glycol), and the cells in which the introduced SLSRP gene was homogeneously recombined with the endogenous SLSRP gene are selected by techniques known in art. In another embodiment, recombinant microorganisms can be produced that contain selected systems that allow to regulate the expression of the introduced gene. For example, the inclusion of an SLSRP gene in a vector that places it under the control of the lac operon allows the expression of the SLSRP gene only in the presence of IPTG. Such regulatory systems are well known in the art. Whether present in a non-replicating extrachromosomal vector or in a vector that is integrated into a chromosome, the SLSRP polynucleotide preferably resides in a vegetable expression cassette. A vegetarian expression cassette preferably contains regulatory sequences capable of directing gene expression in plant cells that are operatively linked such that each sequence can fulfill its function, for example, termination of transcription by polyadenylation signals. Preferred polyadenylation signals are those that originate from Agrobacterium tumefaciens tDNA such as gene 3 called octopinasintetase from the Ti plasmid pTiACH5 (Gielen et al., 1984, EMBO J. 3: 835) or their functional equivalents, but they are also All other functionally active terminators in plants are suitable. Since gene expression in plants is very often not limited to transcription levels, a vegetarian expression cassette preferably contains other operably linked sequences such as translational enhancers such as the excess targeting sequence containing the leader sequence. 5 'untranslated tobacco mosaic virus that encourages the polypeptide relationship by RNA (Gallie et al., 1987, Nucí. Acids Research 15: 8693-871 1). Examples of plant expression vectors include those detailed in: Becker et al., 1992, New plant binary vectors with selectable markers located proximal to the left border, Plant Mol. Biol. 20: 1 195-1 197; and Bevan, 1984, Nucí. Acid Res. 12: 871 1-8721; Vectors for Gene Transfer in Higher Plants; in: Transgenic Plants, Vol. 1, Engineering and Utilization, eds .: Kung and Wu, 1993, Academic Press, S. 15-38. The expression of plant genes must be operatively linked to a suitable promoter that confers the appropriate gene expression in cell-specific or tissue-specific manner. Promoters of utility in the expression cassettes of the invention include any promoter capable of initiating transcription in a plant cell. Such promoters include, without limitation, those obtainable from plants, plant viruses, and bacteria that contain genes that are expressed in plants, such as Agrobacterium and Rhizobium. The promoter can be constitutive, inducible, preferably of developmental stage, preferably cell type, preferably tissue, or preferably organ. Constitutive promoters are active under most conditions. Examples of constitutive promoters include the CaMV 19S and 35S promoters (Odell et al., 1985, Nature 313: 810-812), the CaMV 35S sX promoter (Kay et al., 1987, Science 236: 1299-1302) Sep1 promoter, the rice actin promoter (McEIroy et al., 1990, Plant Cell 2: 163-171), the Arabidopsis actin promoter, the ubiquitano promoter (Christensen et al., 1989, Plant Molec. Biol. 18: 675-689), pEmu (Last et al., 1991, Theor.Appl. Genet. 81: 581-588), the 35S fig mosaic virus promoter, the Smas promoter (Velten et al., 1984, EMBO J 3: 2723-2730), the GRP1-8 promoter, the cinnamyl alcohol dehydrogenase promoter (U.S. Patent No. 5,683,439), the Agrobacterium T-DNA promoters, such as mannopin synthase, nopalin synthase, and octopine synthase. , the minor subunit of ribulose biphosphatecarboxylase (ssuRUBISCO), and the like. The inducible promoters are preferably active under certain environmental conditions, such as the presence or absence of a nutrient or metabolite, heat or cold, light, pathogen attack, anaerobic conditions, and the like. For example, the Brassica hsp80 promoter is induced by heat shock; the PPDK promoter is induced by light; the PR-1 promoters of tobacco, Arabidopsis, and maize are inducible by infection with a pathogen; and the Adh1 promoter is induced by hypoxia and cold stress. The expression of the plant gene can also be facilitated by an inducible promoter (for a review see Gatz, 1997, Annu., Rev. Plant Physiol. Plant Mol. Biol. 48: 89-108). Chemical-inducible promoters are especially suitable if gene expression is desired in a time-specific manner. Examples of said promoters are a salicylic acid inducible promoter (PCT Application No. WO 95/19443), a tetracycline-inducible promoter (Gatz et al., 1992, Plant J. 2: 397-404), and a Ethanol inducible promoter (PCT Application No. WO 93/21334). In a preferred embodiment of the present invention, the inducible promoter is a stress inducible promoter. For the purposes of the invention, stress-inducible promoters are preferably active in one or more of the following stresses: sub-optimal conditions associated with stress by salinity, drought, temperature, metal, chemicals, pathogens, and oxidative stress. Stress inducible promoters include, without limitation, Cor78 (Chak et al., 2000, Plant 210: 875-883, Hovath et al., 1993, Plant Physiol. 103: 1047-1053), Cor15a (Artus et al., 1996, PNAS 93 (23): 13404-09), Rci2A (Medina et al., 2001, Plant Physiol., 125: 1655-66; Nylander et al., 2001, Plant Mol. Biol. 45: 341-52; Navarre and Goffeau, 2000, EMBO J. 19: 2515-24; Capel et al., 1997, Plant Physiol., 15: 569-76), Rd22 (Xiong et al., 2001, Plant Cell 13: 2063-83; Abe et al., 1997, Plant Cell 9: 1859-68, Iwasaki et al., 1995, Mol. Gen. Genet 247: 391-8), cDet6 (Lang and Palve, 1992, Plant Mol. Biol. 20: 951 -62), ADH1 (Hoeren et al., 1998, Genetics 149: 479-90), KAT1 (Nakamura et al., 1995, Plant Physiol. 109: 371-4), KST1 (Müller-Róber et al., 1995 , EMBO 14: 2409-16), Rha1 (Terryn et al., 1993, Plant Cell 5: 1761-9; Terryn et al., 1992, FEBS Lett. 299 (3): 287-90), ARSK1 (Atkinson et al., 1997, # of access to GenBank L22302, and PCT application No. WO 97/20057), PtxA (Plesch et al., # Of access to GenBank X67427), SbHRGP3 (Ahn et al., 1996, Plant Cell 8: 1477-90), GH3 (Liu et al., 1994, Plant Cell 6: 645-57), the pathogen-inducible gene promoter PRP1 (Ward et al. ., 1993, Plant, Mol. Biol. 22: 361-366), the hsp80 tomato-inducible heat promoter (U.S. Patent No. 5187267), cold-inducible promoter of potato alpha-amylase (request from PCT No. WO 96/12814), or the pinll-inducible promoter (European Patent No. 375091). For other examples of drought-inducible promoters, cold, and salts, such as the RD29A promoter, see Yamaguchi-Shinozalei et al., 1993, Mol. Gen. Genet. 236: 331-340. Preferred developmental stage promoters are preferably expressed at certain stages of development. Preferred tissue and organ promoters include those that are preferentially expressed in certain tissues and organs, such as leaves, roots, seeds, or xylem. Examples of tissue preference and organ preference promoters include, without limitation, fruit preference promoters, preferably of ovule, preferably of male tissue, preferably of seed, preferably of integument, preferably of tubercle, of stem preference, preferably of pericarp, and preferably of leaf, preferably of stigma, preferably of pollen, preferably of anthers, preferably of petals, preferably of sepals, preferably of pedicel, preferably of silique, preferably of trunk, preferably root, and the like. Seed preference promoters are preferably expressed during the development and / or germination of the seed. For example, seed preference promoters may be embryo preference promoters, preferably endosperm, and preferably seed coat. See Thompson et al., 1989, BioEssays 10: 108. Examples of seed preference promoters include, without limitation, cellulosesintetase (celA), Cim1, gamma-zein, globulin-1, 19 kD corn zein (cZ19B1), and the like. Other suitable tissue preference or organ preference promoters include the rapeseed napkin gene promoter (U.S. Patent No. 5,608,152), the Vicia faba USP promoter (Baeumlein et al., 1991). , Mol.Gen. Genet 225 (3): 459-67), the Arabidopsis oleosin promoter (PCT application No. WO 98/45461), the phaseolin promoter of Phaseolus vulgaris (U.S. Pat. No. 5,504,200), the Brassica Bce4 promoter (PCT application No. WO 91/13980), or the Legumin B4 promoter (LeB4; Baeumlein et al., 1992, Plant Journal, 2 (2): 233 -9), in addition to promoters that confer specific expression of seed in monocotyledonous plants such as corn, barley, wheat, rye, rice, etc. Suitable suitable promoters are the Ipt2 or Ipt1 gene promoter from barley (PCT application No. WO 95/15389 and PCT application No. WO 95/23230) or those described in the PCT application No. WO 99 / 16890 (promoters of barley hordein gene, rice glutelin gene, rice orizin gene, rice prolamin gene, wheat gliadin gene, wheat glutelin gene, oat glutelin gene, kasirin gene of sorghum, and secalin gene of rye). Other promoters of utility in the expression cassettes of the invention include, without limitation, the main promoter of chlorophyll a / b binding proteins, histone promoters, the Ap3 promoter, the # -conglucin promoter, the napin promoter, the soybean lecithin promoter, the 15kD corn zein promoter, the 22kD zein promoter, the 27kD zein promoter, the y-zein promoter, the waxy, rough 1, rugose 2 promoters, and bronze, the Zm13 promoter (U.S. Patent No. 5,086,169), the corn polygalacturonase (PG) promoters (U.S. Patent Nos. 5,412,085 and 5,545,546), and the SGB6 promoter (U.S. Patent No. 5,470,359), in addition to synthetic promoters or other natives. Additional flexibility can be obtained by controlling heterologous gene expression in plants through the use of DNA binding domains and response elements from heterologous sources (ie, DNA-binding domains from non-plant sources). An example of such a heterologous DNA binding domain is the LexA DNA binding domain (Brent and Ptashne, 1985, Cell 43: 729-736). The invention also provides a recombinant expression vector comprising an SLSRP DNA molecule of the invention cloned into the expression vector in antisense orientation. That is, the DNA molecule is operably linked to a regulatory sequence that allows the expression (by transcription of the DNA molecule) of an RNA molecule that is antisense to an SLSRP mRNA. Regulatory sequences operably linked to a nucleic acid molecule cloned in antisense orientation can be chosen to direct the continuous expression of the antisense RNA molecule in a variety of cell types. For example, viral promoters and / or promoters, regulatory sequences can be chosen to direct tissue-specific, cell-specific, constitutive direct expression of the antisense RNA. The antisense expression vector may be in the form of a recombinant plasmid, phagemic, or attenuated virus where antisense nucleic acids are produced under the control of a high efficiency regulatory region. The activity of the regulatory region can be determined by the cell type in which the vector is introduced. For the analysis of the regulation of gene expression with antisense genes, see Weintraub, H. et al., 1986, Antisense [Q RNA as a molecular tool for genetic analysis, Reviews - Trends in Genetics, Vol. 1 (1), and Mol et al., 1990, FEBS Letters 268: 427 ^ 130. Another aspect of the invention relates to host cells in which a recombinant expression vector of the invention was introduced. The terms "host cell" and "recombinant host cell" are used interchangeably herein. HE understands that said terms refer not only to the particular subject cell but that it is applied to the progeny or the possible progeny of said cell. Since certain modifications may occur in successive generations due to mutation or environmental influences, said progeny may not be identical to the progenitor cell, but is still included in the scope of the term as used herein. A host cell can be any prokaryotic or eukaryotic cell. For example, SLSRP can be expressed in bacterial cells such as C. glutamicum, insect cells, fungal cells, or mammalian cells (such as Chinese hamster ovary (CHO) cells or COS cells), algae, ciliates, plant cells , fungal, or other microorganisms such as C. glutamicum. Other suitable host cells are known to those skilled in the art. The nucleic acid molecules, polypeptides, polypeptide homologs, fusion polypeptides, primers, vectors, and host cells described herein may be used in one or more of the following methods: identification of Physcomitrella patens or Glycine max and related organisms; mapping of genomes or organisms related to Physcomitrella patens or Glycine max; identification and localization of sequences of interest in Physcomitrella patens or Glycine max; evolutionary studies; determination of SLSRP regions required for the function; modulation of SLSRP activity; modulation of the metabolism of one or more cellular functions; modulation of transmembrane transport of one or more 5 compounds; modulation of stress resistance; and modulation of the expression of SLSRP nucleic acids. In one embodiment of these methods, SLSRP acts as an active plant transcription factor. The moss Physcomitrella patens or Glycine max represent a member of the mosses. It is related to other mosses such as Ceratodon purpureus which is capable of growth in the absence of light. Mosses such as Ceratodon and Physcomitrella share a high degree of sequence identity at the level of DNA and polypeptide sequences, which allows the use of heterologous analysis of DNA molecules with probes that evolve from other mosses or organisms, which allows derivation of a suitable consensus sequence for the heterologous Q search or the notation and prediction of gene functions in third species. The ability to identify such functions accordingly can have significant relevance, p. eg, the prediction of the substrate specificity of the enzymes. In addition, these nucleic acid molecules can serve as reference points for the mapping of moss genomes, or genomes of related organisms. The SLSRP nucleic acid molecule of the invention has various uses. More importantly, the nucleic acid and amino acid sequences of the present invention can be used to transform plants, and thus increase growth and induce tolerance to stresses such as drought, high salinity, and cold. The present invention consequently provides a transgenic plant transformed with an SLSRP nucleic acid, wherein the expression of the nucleic acid sequence in the plant results in increased plant growth and tolerance to environmental stress, compared to a variety of wild type of the plant. The transgenic plant can be a monocot or a dicot. The invention also provides that the transgenic plant can be selected from corn, wheat, rye, oats, triticale, rice, barley, soybean, peanut, cotton, rapeseed, cañola, cassava, pepper, sunflower, tagetes, solanaceous plants, potato, tobacco, eggplant, tomato, Vicia species, peas, alfalfa, coffee, cocoa, tea, Salix species, oil palm, coconut, perennial grass, and forage cereals, for example. In particular, the present invention describes the use of the expression of PpSCLI, PpSCL2, PpSCL3, and GmSCLI to subject plants to engineered growth and tolerance to drought, salts, and / or cold. This strategy has been demonstrated in the present for Arabidopsis thaliana, but its application is not restricted to these plants. Accordingly, the invention provides a transgenic plant containing an SLSRP such as PpSCLI as defined in SEQ ID NO: 2, PpSCL2 as defined in SEQ ID NO: 4, PpSCL3 as defined in SEQ ID NO: 6, or GmSCLI as defined in SEQ ID NO: 8, wherein the plant has growth increase and tolerance to an environmental stress that is selected from one or more of the group consisting of drought, increase of salts, or increase or decrease of temperature. In the preferred embodiments, environmental stress is drought or temperature decrease. Accordingly, the invention provides a method for producing a transgenic plant with a nucleic acid encoding SLSRP, wherein expression of the nucleic acid in the plant results in increased growth and tolerance to environmental stress, compared to a variety Wild type of the plant comprising: a) introducing into an plant cell an expression vector comprising a SLSRP nucleic acid, and b) generating from said plant cell a transgenic plant with increased growth and tolerance to environmental stress, compared to a variety of wild type of the plant. The plant cell includes, without limitation, a protoplast, a gamete-producing cell, and a cell that regenerates into a whole plant. As used herein, the term "transgenic" refers to any plant, plant cell, callus, plant tissue, or part of plants, which contains all or at least part of a recombinant polynucleotide. In many cases, all or part of the recombinant polynucleotide is stably integrated into a chromosome or stable extrachromosomal element, so that it is passed on to successive generations. In preferred embodiments, the SLSRP nucleic acid encodes a protein comprising the polypeptide of SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6, or SEQ ID NO: 8. The present invention also provides a method for modulating the growth of a plant and the tolerance to environmental stress comprising modifying the expression of a nucleic acid encoding SLSRP in the plant. Plant growth and tolerance to environmental stress may increase or decrease as the expression of an SLSRP is increased or decreased, respectively. Preferably, plant growth and tolerance to environmental stress are increased by increasing the expression of an SLSRP. The expression of an SLSRP can be modified by any other method known to those skilled in the art. Methods for increasing the expression of SLSRP can be used where the plant is transgenic or non-transgenic. In cases where the plant is transgenic, the plant can be transformed with a vector containing any of the above-described nucleic acids encoding SLSRP, or the plant can be transformed with a promoter that directs the expression of native SLSRP in the plant , for example. The invention provides that said promoter may be preferably tissue, regulated by the development, stress inducible, or one of its combinations. Alternatively, non-transgenic plants may have modified the native expression of SLSRP by inducing a native promoter. The expression of PpSCLI as defined in SEQ ID NO: 1, PpSCL2 as defined in SEQ ID NO: 3, PpSCL3 as defined in SEQ ID NO: 5, or GmSCLI as defined in SEQ ID NO: 7 in white plants can be achieved, without limitations, by one of the following examples : a) constitutive promoter, b) stress-inducible promoter, c) chemical-inducible promoter, and d) overexpression of the promoter by engineering, for example, with transcription factors derived from zinc fingers (Greisman and Pabo, 1997, Science 275: 657). In a preferred embodiment, transcription of the SLSRP is modulated by transcription factors derived from zinc fingers (ZFP) as described in Greisman and Pabo, 1997, Science 275: 657 and manufactured by Sangamo Biosciences, Inc. These ZFP they comprise a DNA recognition domain and a functional domain that causes the activation or repression of a target nucleic acid such as an SLSRP nucleic acid. Accordingly, ZFP activations and repressions can be created that specifically recognize the SLSRP promoters described above and used to increase or decrease the expression of SLSRP in a plant, and thus modulate the stress tolerance of the plant. The present invention also includes the identification of the PpSCLI homologs as defined in SEQ ID NO: 1, PpSCL2 as defined in SEQ ID NO: 3, PpSCL3 as defined in SEQ ID NO: 5, or GmSCLI as defined in SEQ ID NO: 7 in a white plant, in addition to the homologous promoter. The invention also provides a method for increasing the expression of a gene of interest in a host cell, compared to a wild-type variety of the host cell, wherein the gene of interest is transcribed in response to an SLSRP, comprising: a ) transforming the host cell with an expression vector comprising an acid coding for SLSRP, and b) expressing the SLSRP within the host cell, thereby increasing the expression of the gene transcribed in response to SLSRP, compared to a wild type strain of the host cell. In addition to introducing the SLSRP nucleic acid sequences into transgenic plants, these sequences can also be used to identify an organism such as Physcomitrella patens, Glycine max, or a closely related species. They can also be used to identify the presence of Physcomitrella patens, Glycine max, or a related species in a mixed population of microorganisms. The invention provides the nucleic acid sequences of the gene of Physcomitrella patens and Glycine max; by probing the genomic DNA extracted from a culture of a single or mixed population of microorganisms under stringent conditions with a probe covering a region of the gene of Physcomitrella patens or Glycine max that is unique to that organism, it is possible to ensure the presence of that organism. In addition, the nucleic acid and polypeptide molecules of the invention can serve as markers for specific regions of the genome. This is useful not only for genome mapping, but also in functional studies of polypeptides from Physcomitrella patens or Glycine max. For example, to identify the region of the genome to which particular DNA-binding agent of Physcomitrella patens binds, the genome of Physcomitrella patens can be digested, and the fragments incubated with the DNA-binding polypeptide. These fragments that fix the polypeptide can also be probed with the nucleic acid molecules of the invention, preferably with easily detectable labels. The union of said nucleic acid molecules to the fragment of the genome makes it possible to locate the fragment in the genome map of Physcomitrella patens, and when they are carried out many times with different enzymes, the rapid determination of the nucleic acid sequence is facilitated. binds the polypeptide. In addition, the nucleic acid molecule of the invention can be sufficiently identical to the sequences of related species, that is why these nucleic acid molecules can act as markers for the construction of a genomic map in related mosses. The SLSRP nucleic acid molecules of the invention are also useful for studies of evolutionary structure and polypeptides. The processes of transcription and signal transduction in which the molecules of the invention participate are used in a wide variety of prokaryotic and eukaryotic cells; By comparing the sequences of the nucleic acid molecules of the present invention with those encoding similar proteins from other organisms, the evolutionary relationship of the organisms can be evaluated. Similarly, said comparison allows to evaluate which regions of the sequence are conserved and which are not, which may contribute to determine the regions of the polypeptide that are essential for the functioning of the transcription factor. This type of determination is valuable for polypeptide engineering studies and can indicate what the polypeptide can tolerate in terms of mutagenesis, without losing function. The manipulation of the SLSRP nucleic acid molecule of the invention can result in the production of SLSRP with functional differences over wild-type SLSRPs. These polypeptides may have improved efficiency or activity, they may be present in greater amount in the cell than usual, or they may be decreased in efficiency and activity. There are numerous mechanisms by which the alteration of an SLSRP of the invention can directly affect the stress response and / or stress tolerance. In the case of plants that express SLSRP, the increase in tolerance can lead to greater partition of can and / or solute salts in tissue and plant organs.

The effect of genetic modification on plants, C. glutamicum, fungi, algae, or ciliates on plant growth and / or stress tolerance can be assessed by cultivation of the modified microorganisms or plants in conditions below appropriate conditions and then analyze the characteristics of growth and / or metabolism of the plant. Such analysis techniques are well known to those skilled in the art, and include dry weight, wet weight, polypeptide synthesis, carbohydrate synthesis, lipid synthesis, transpiration rates, general plant and / or crop yields. , flowering, reproduction, seed formation, root growth, respiration rates, photosynthesis rates, etc. (Applications of HPLC in Biochemistry in: Laboratory Techniques in Biochemistry and Molecular Biology, vol.17, Rehm et al., 1993 Biotechnology, vol.3, Chapter III: Product recovery and purification, page 469-714, VCH: Weinheim et al. ., 1988, Bioseparations: downstream processing for biotechnology, John Wiley and Sons; Kennedy and Cabral, 1992, Recovery processes for biological materials, John Wiley and Sons; Shaeiwitz and Henry, 1988, Biochemical separations, in: Ulmann's Encyclopedia of Industrial Chemistry, vol. B3, Chapter 11, page 1-27, VCH: Weinheim; and Dechow, 1989, Separation and purification techniques in biotechnology, Noyes Publications). For example, the yeast expression vector comprising the nucleic acids described herein, or fragments thereof, can be constructed and transformed into Saccharomyces cerevisiae by standard protocols. The transgenic cells obtained can be analyzed to detect faults or alterations in their tolerance to stress due to drought, salts, and temperature. Similarly, plant expression vectors comprising the nucleic acids described herein, or fragments thereof, can be constructed and transformed into a suitable plant cell such as Arabidopsis, soybean, rapeseed, corn, wheat, Medicago truncatula, etc. , through standard protocols. The obtained transgenic cells and / or the derived plants can then be tested to detect faults or alterations of the growth increase and / or tolerance to stresses by drought, salts and temperature. The engineering of one or more SLSRP genes of the invention may also result in alterations of activities that indirectly impact growth and / or stress response and / or stress tolerance of algae, plants, ciliates, or fungi, or other microorganisms such as C. glutamicum. For example, the normal biochemical processes of metabolism result in the production of a variety of products (eg, hydrogen peroxide and other reactive oxygen species) that can actively interfere with the same metabolic processes. JQ In addition, the sequences described herein, or their fragments, can be used to generate knockout mutations in the genomes of various organisms, such as bacteria, mammalian cells, yeast cells, and plant cells (Girke, T., 1998). , The Plant Journal 15: 39-48). The knockout cells obtained can then be evaluated for their ability to tolerate various stress conditions, and the 1 5 effect on the phenotype and / or genotype of the mutation. For other methods of gene inactivation, see U.S. Patent No. 6,004,804 and Puttaraju et al., 1999, Nature Biotechnology 17: 246-252. The aforementioned mutagenesis strategies for SLSRP result in increased growth and resistance to stress that are not intended or limiting; The variations of these strategies will be readily apparent to experts in the art. By such strategies, and by incorporating the mechanisms described herein, the nucleic acid and polypeptide molecules of the invention can be used to generate algae, ciliates, plants, fungi, or other microorganisms such as C. glutamicum that express the molecules mutated nucleic acid and SLSRP polypeptide in such a way that tolerance increases. The present invention also provides antibodies that bind specifically to SLSRP, or a portion thereof, as encoded by a nucleic acid described herein. Antibodies can be prepared by many well-known methods (See, eg, Harlow and Lane, 1988, "Antibodies; A 0 Laboratory Manual, "Cold Spring Harbor Laboratory, Cold Spring Harbor, NY." The phrases "selectively binds" and "specifically binds" with the polypeptide refers to the binding reaction that determines the presence of the polypeptide in a population Accordingly, under certain immunoassay conditions, the specific antibodies bound to a particular polypeptide do not bind in a significant amount to the other polypeptides present in a sample.Selective binding of an antibody under said conditions may require an antibody selected for its specificity for a particular polypeptide A variety of immunoassays may be used to select antibodies that selectively bind to a particular polypeptide For example, solid phase immunoassays by ELISA are routinely used to select antibodies with selective immunoreaction for a polypeptide See Har low and Lane, 1988, "Antibodies, A Laboratory Manual" Cold Spring Harbor Publications, NY, for a description of the immunoassay formats and conditions that can be used to determine selective fixation. In some cases, it is convenient to prepare monoclonal antibody from several hosts. A description of the techniques for preparing said monoclonal antibodies can be found in Stites et al., Eds., "Basic and Clinical Immunology," (Lange Medical Publications, Los Altos, Calif., Fourth Edition) and their references cited therein, and in Harlow and Lane, 1988, "Antibodies, A Laboratory Manual" Cold Spring Harbor Publications, NY. Throughout this application, reference was made to various publications. The descriptions of all those publications and those references cited in those publications are hereby incorporated herein by reference in their entirety, for the purpose of more fully describing the state of the art to which the present invention pertains. It should also be understood that the above refers to the preferred embodiments of the present invention and that many changes can be made without departing from the scope of the invention. The invention is also illustrated by the following examples, which in no way should be construed as limiting the scope of the present. On the contrary, it should be clearly understood that many other embodiments, modifications, and equivalents may be resorted to which, after reading the description herein, may suggest to those skilled in the art without departing from the spirit of the present invention and / or the scope of the appended claims. EXAMPLES Example 1 Growth of Physcomitrella patens cultures For this study plants of the species Physcomitrella patens (Hedw.) B.S.G. from the collection of the genetic studies section of the University of Hamburg. They originated in strain 16/14 gathered by H.L.K. Whitehouse in Gransden Wood, Huntingdonshire (England), which was a subculture of a spore of Engel (1968, Am. J. Bot. 55: 438-446). The proliferation of the plants was carried out by means of spores and by the regeneration of the gametophytes. The protonema developed from the haploid spore as a chloroplast rich chloronema and low chloroplast caulonema, in which buds formed after approximately 12 days. These grew to give anteroid and archegonias carrying gametophores. After fertilization, the diploid sporophyte was obtained with a short mushroom and the spore capsule, in which the meiospores matured. Cultivation was carried out in a heated chamber with an air temperature of 25 ° C and light intensity of 55 micromol m2 s "1 (white light, Philips TL 65W / 25 fluorescent tube) and a light / dark change of 16/8 The moss was modified in liquid culture with Knop medium according to Reski and Abel (1985, Plant 165: 354-358) or cultivated on solid Knop medium with 1% oxoid sugar (Unipath, Basingstoke, England) Proteomemes used for the isolation of RNA and DNA were cultured in liquid aerated cultures, the protonemas were changed every 9 days and transferred to a fresh culture medium Example 2 Isolation of total plant DNA The details of total DNA isolation refer to the processing of one gram of fresh weight of plant material The materials used include the following buffer: CTAB buffer: 2% (w / v) N-cetyl-N, N, N-trimethylammonium bromide (C ); 100 mM Tris HCl pH 8.0; 1.4 M NaCl; 20 mM EDTA; N-Lauryl sarcosine buffer: 10% (w / v) N-lauryl sarcosine; 100 mM Tris HCl pH 8.0; and 20 mM EDTA. The plant material was crushed in liquid nitrogen in a mortar to give a fine powder and transferred to 2 mL Eppendorf flasks. Then the frozen plant material was covered with a layer of 1 ml of decomposition buffer (1 ml of CTAB buffer, 100 μ of N-lauryl sarcosine buffer, 20 μ of β-mercaptoethanol, and 10 μ of proteinase solution). K, 10 mg / ml) and incubated at 60 ° C for one hour with continuous agitation. The obtained homogenate is distributed in two Eppendorf glasses (2 ml) and extracted twice by shaking with the same volume of chloroform / isoamyl alcohol (24: 1). For the separation of phases, centrifugation is performed at 8000 x g and room temperature for 15 minutes in each case. The DNA is then precipitated at -70 ° C for 30 minutes with ice-cold isopropanol. The precipitated DNA is pelleted at 4 ° C and 10,000 g for 30 minutes and resuspended in 180 μ? of TE buffer (Sambrook et al., 1989, Cold Spring Harbor Laboratory Press: ISBN 0-87969-309-6). For further purification the DNA is treated with NaCl (1.2 M final concentration) and re-precipitated at -70 ° C for 30 minutes with two vecers the volume of absolute ethanol. After a washing step with 70% ethanol, the DNA is dried and then recovered with 50 μ? of H2O + RNAse (50 mg / ml final concentration). The DNA is dissolved overnight at 4 ° C, and then digestion is performed with RNAse at 37 ° C for 1 hour. The DNA is stored at 4 ° C. Example 3 Isolation of total RNA and construction of poly- (A) + RNA library and cDNA Physcomitrella patens library For the investigation of the transcripts, total RNA and poly (A) + RNA are isolated. The total RNA was obtained from the wild-type protonema of 9 days, after the GTC- method (Reski et al., 1994, Mol.Gen. Genet., 244: 352-359). Poly (A) + RNA was isolated by beads from Dyna Beads® (Dynal, Oslo, Norway) according to the manufacturer's protocol instructions. After determining the concentration of RNA or poly (A) + RNA, RNA was precipitated by addition of 1/10 volume of 3 M sodium acetate pH 4.6 and 2 volumes of ethanol, and stored at -70 ° C . For the construction of the cDNA library, the synthesis of the first chain was achieved by reverse transcriptase of murine leukemia virus (Roche, Mannheim, Germany) and oligo-d (T) -primers, the synthesis of the second chain by incubation with DNA polymerase I, Klenow enzyme and digestion with RNAseH at 12 ° C (2 hours), 16 ° C (1 hour), and 22 ° C (1 hour). The reaction was stopped by incubation at 65 ° C (10 minutes) and then transferred onto ice. The double-stranded DNA molecules were ligated by T4-DNA- (Roche, Mannheim) at 37 ° C (30 minutes). The nucleotides were removed by extraction with phenol / chloroform and spindle columns of Sephadex G50. EcoRI adapters (Pharmacia, Freiburg, Germany) were ligated to the ends of the cDNA by T4-DNA ligase (Roche, 12 ° C, overnight) and phosphorylated by incubation with the polynucleotide kinase (Roche, 37 ° C, 30 minutes). This mixture was subjected to separation on a low melting point agarose gel. DNA molecules greater than 300 base pairs were eluted from the gel, extracted with phenol, concentrated with Elutip-D columns (Schleicher and Schuell, Dassel, Germany), and ligated to the arms of the vector and packaged in lambda ZAPII phage or lambda phage ZAP-Express with Gigapack Gold Kit (Stratagene, Amsterdam, The Netherlands) with the material and following the manufacturer's instructions. Example 4 Determination of sequence and notation of the EST function of Physcomitrella patens The cDNA libraries described in Example 3 were used to determine the DNA sequence according to standard methods, and in particular, by the chain termination method with ABI PRISM Big Dye Terminator Cycle Sequencing Ready Reaction Kit (Perkin-Elmer, Weiterstadt, Germany). Random sequence determinations were performed after preparation of the preparation plasmid was prepared from the cDNA libraries by mass cleavage in vivo, retransformation, and subsequent plating of DH10B on agar plates (material and details of the Stratagene protocol, Amsterdam , Netherlands). Plasmid DNA was prepared from 24-hour culture of E. coli grown in Luria-Broth medium containing ampicillin (See Sambrook et al., 1989, Cold Spring Harbor Laboratory Press: ISBN 0-87969-309-6) in a Qiagene DNA preparation robot (Qiagen, Hilden) according to the manufacturer's protocols. Sequence primers were used with the following nucleotide sequences: -CAGGAAACAGCTATGACC-3 'SEQ ID NO: 9 5' -CTAAAGGG AACAAAAGCTG-3 'SEQ ID NO: 10 5' -TGTAAAACG ACGGCCAGT-3 'SEQ ID NO: 11 sequences were processed and scored with an EST-MAX software package commercially available from Bio-Max (Munich, Germany). The program incorporates practically all the bioinformatic methods of importance for the functional and structural characterization of the protein sequence. For reference, see the website of pedant.mips.biochem.mpg.de. The main algorithms incorporated in EST-MAX are: FASTA (Very sensitive sequence dates searches with estimates of statistical significance; Arvejasrson, 1990, Rapid and sensitive sequence comparison with FASTP and FASTA, Methods Enzymol. 183: 63-98); BLAST (Very Sensitive Sequence Searches Searches with Estimates of Statistical Significance; Altschul et al., Basic local alignment search tool, Journal of Molecular Biology 215: 403-10); PREDATOR (High-accuracy secondary structure prediction from single and multiple sequences, Frishman and Argos, 1997, 75% accuracy in protein secondary structure prediction, Proteins 27: 329-335); CLUSTAL W (Multiple sequence alignment, Thompson et al., 1994, CLUSTAL W (improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice, Nucleic Acids Research 22: 4673-4680); (Transmembrane region prediction from multiple aligned sequences; Persson and Argos, 1994, Prediction of transmembrane segments in proteins utilizing multiple sequence alignments, J. Mol. Biol. 237: 182-192); ALOM2 (Transmembrane region prediction from single sequences; Klein et al., Prediction of protein function from sequence properties: A discriminate analysis of a datábase. Biochim. Biophys. Acta 787: 221-226 (1984). Version 2 by Dr. K. Nakai); PROSEARCH (Detection of PROSITE sequence of protein pattems; Kolakowski et al., 1992, ProSearch: fast searching of protein sequence with regular expression pattems related to protein structure an function, Biotechniques 13, 919-921); BLIMPS (Similarity searches against a database of ungapped blocks, Wallace and Henikoff, 1992); PATMAT (a searching and extraction program for sequence, pattem and block queries and databases, CABIOS 8: 249-254, Written by Bill Alford). Example 5 Identification of Physcomitrella patens ORFs corresponding to PpSCLI, PpSCL2 and PpSCL3 Partial cDNAs of P. patens (ESTs) were identified in the sequencing program of P. patens EST, using the EST-MAX program through the BLAST analysis. The full-length nucleotide sequences of PpSCLI, PpSCL2 and PpSCL3 are defined in SEQ ID NO: 1, SEQ ID NO: 3 and SEQ ID NO: 5, respectively. The predicted amino acid sequences of PpSCLI (SEQ ID NO: 2), PpSCL2 (SEQ ID NO: 4) and PpSCL3 (SEQ ID NO: 6) shared significant sequence identities and similarities to scarecrow-like gene products as indicated in Tables 1, 2 and 3. Table 1 Degree of amino acid identity and similarity of PpSCLI (EST 386) and other homologous proteins (the GCG breccias program was used: gap penalty: 10, gap extension penalty: 0.1 scoring matrix: blosum 62) Table 2 Degree of amino acid identity and similarity of PpSCL2 (EST 166) and other homologous proteins (the GCG breccias program was used: gap penalty: 10, gap extension penalty: 0.1, score matrix: blosu Table 3 Degree of amino acid identity and similarity of PpSCL3 (EST 512) and other homologous proteins (gap program GCG was used: gap penalty: 10, gap extension penalty: 0.1, score matrix: blosum 62 ) Example 6 Cloning of the full length cDNA from Physcomitrella patens encoding PpSCL.1, PpSCL2 and PpSCL3 To isolate the clones encoding PpSCLI (SEQ ID NO: 1), PpSCL2 (SEQ ID NO: 3) and PpSCL3 (SEQ ID NO: 5) of total length of P. patens, cDNA libraries were created with the SMART RACE cDNA amplification kit (Clontech Laboratories), according to the manufacturer's instructions. The isolated total RNA was used as template as described in Example 3. The cultures were treated before RNA isolation in the following manner: Salt Stress: 2, 6, 12, 24, 48 hours with medium supplemented with NaCl 1 M; cold stress: 4 ° C in the same moments as for salt; drought stress: the cultures were incubated in a dry filter paper at the same time as for the salt. 5 'RACE protocol The EST sequences identified from the database search were used as indicated in Example 4, to designate oligos for RACE (see Table 6). The extended sequences for these genes were obtained by carrying out a rapid amplification of the cDNA ends by polymerase chain reaction (RACE PCR), making use of the Advantage 2 PCR kit (Clontech Laboratories) and the SMART RACE cDNA amplification kit. (Clontech Laboratories) with a Biometra T3 thermal cycler according to the manufacturer's instructions. The sequences obtained from the RACE reactions corresponded to the full-length coding region and were used to designate oligos for full-length cloning of the respective gene (see full-length amplification below). Table 4 Scheme and primers used to clone full-length clones Total length amplification Total length clones corresponding to PpSCU (SEQ ID NO: 1), PpSCL2 (SEQ ID NO: 3), or PpSCL3 (SEQ ID NO: 5) were obtained, carrying out the polymerase chain reaction ( PCR) with gene-specific primers and original EST as a template. The conditions for the reaction were standard conditions with PWO DNA polymerase (Roche). The PCR was carried out according to the standard conditions and according to the manufacturer's protocols (Sambrook et al., 1989, Molecular Cloning, A Laboratory Manual. 2nd Edition, Coid Spring Harbor Laboratory Press, Coid Spring Harbor, NY, Biometra T3 Thermocycler). The parameters for the reaction were: five minutes at 94 ° C followed by five cycles of one minute at 94 ° C, one minute at 50 ° C and 4 minutes at 72 ° C. This was followed by 25 cycles of one minute at 94 ° C, one minute at 65 ° C and 4 minutes at 72 ° C. These parameters generated a 4.0 kb fragment for PpSCLI, 2.8 kb for PpSCL2 and 2.3 kb for PpSCL3. The amplified fragments were extracted from agarose gel with a QIAquick gel extraction kit (Qiagen) and ligated to a pCR 2.1 TOPO vector (Invitrogen) according to the manufacturer's instructions. Recombinant vectors were transformed into Top10 cells (Invitrogen) using standard conditions (Sambrook et al., 1989, Molecular Cloning, A Laboratory Manual, 2nd Edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY). The transformed cells were selected for LB agar containing 100 μg / ml of carbenicillin, 0.8 mg of X-gal (5-bromo-4-chloro-3-indolyl-pD-galactoside) and 0.8 mg of IPTG (isopropylthio-β-D-galactonoxide) grown overnight at 37 ° C. Colonies were selected and used to inoculate 3 ml of liquid LB containing 100 μg / ml ampicillin and cultured overnight at 37 ° C. The plasmid DNAs were extracted using the QIAprep Spin Miniprep kit (Qiagen) according to the manufacturer's instructions. Analysis of subsequent clones and restriction mapping were carried out according to standard molecular biology techniques (Sambrook et al., 1989, Molecular Cloning, A Laboratory Manual, 2nd Edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor , NY). Total length nucleotide sequences of PpSCLI (SEQ ID NO: 1), PpSCL2 (SEQ ID NO: 3) or PpSCL3 (SEQ ID NO: 5) were analyzed with Biomax and Vector NTI. The amino acid sequences of PpSCLI (SEQ ID NO: 2), PpSCL2 (SEQ ID NO: 4) and PpSCL3 (SEQ ID NO: 6) have homologies with the GRS family of transcription factors. For example, the amino acid sequence PpSCLI (SEQ ID NO: 2) has homology to the GRAS family of transcription factors (http://www.sanger.ac.uk/cgi-bin/Pfam/getacc7PF03514). The three most conserved motifs in the GRAS gene family, the VHIID, PFYRE and SAW motifs, are in PpSCLI (SEQ ID NO: 2). A comparative search of PpSCLI (SEQ ID NO: 2) in ERGO sequences of 12 Archaea, 145 Bacteria and 84 eukaryotes (http: //ergo.zh.basf-ag.de:8080/ERGO/) identified similar sequences in Arabidopsis , corn and tomato (minimum rigor of 0.00001). A comparative protein sequence search PpSCLI (SEQ ID NO: 2), PpSCL2 (SEQ ID NO: 4) and PpSCL3 (SEQ ID NO: 6) with the public database NCBI identified GRAS / SCR sequences from SwissProt (<; e-40) as indicated in Tables 1, 2 and 3. Figures 1, 2 and 3 show the relative homology and detailed alignment of the amino acid sequences of PpSCLI, PpSCL2, PpSCL3 and GmSCLI (SEQ ID NO. : 2, 4, 6, and 8) with the sequences of six known members of the GRAS family. Tissue collection, RNA isolation and construction of the cDNA library. Soy bean plants were grown under a variety of conditions and treatments, and different tissues were collected at different stages of development. The growth of the plant and its harvesting were done in a strategic way, so that the probability of collecting all the expressible genes in at least one or vahas of the resulting libraries is maximized. The mRNA was isolated as described in Example 3 from each of the collected samples, and cDNA libraries were constructed. Amplification steps were not used in the production process of the library in order to minimize the redundancy of genes within the sample and to retain the expression information. All libraries were generated 3 'from purified mRNA in oligo dT columns. Colonies were randomly taken from the transformation of the cDNA library in E. coli and placed in microtiter plates. Hybridization of probes Plasmid DNA was isolated from E. coli colonies and then splashed onto membranes. A battery of 288 radiolabelled 7 P-labeled 7-mer oligonucleotides was sequentially hybridized to these membranes. To increase performance, duplicate membranes were processed. After each hybridization, a blot image was captured during a phosphor image scan to generate a hybridization profile for each oligonucleotide. This image with raw data was automatically transferred to a computer through LIMS. Absolute identity was maintained by barcode for the image cassette, the filter and the orientation within the cassette. The filters were then treated using relatively moderate conditions to remove the bound probes and return to the hybridization chambers for a round of hybridizations. The cycle of hybridization and imaging was repeated until a set of 288 oligomers was completed. After completing the hybridizations, a profile was generated for each spot (represents an insertion of cDNA), for which the 7-mer oligonucleotides with radioactive label 288 33P bound to this particular spot (insertion of cDNA) were marked, and to what extent . This profile is defined as the form generated by that clone. Each clone form was compared with all other signatures generated by the same agency to identify the clusters of related signatures. This process "classifies" all the clones of an organism in clusters before sequencing. The clones were classified into various clusters based on their identical or similar hybridization signatures. A cluster should be indicative of the expression of an individual gene or a family of genes. A by-product of this analysis is an expression profile for the abundance of each gene in a particular library. One-way sequencing was used from the 5 'end to predict the function of the particular clones by similarity and search of motifs in the sequence databases.

The full-length DNA sequences of PpSCLI (SEQ ID NO: 1), PpSCL2 (SEQ ID NO: 3) or PpSCL3 (SEQ ID NO: 5) were related to databases of contig property BPS in the value E of E-10. (Altschul, Stephen et al., Gapped BLAST and PSI_BLAST: a new generation of protein datbase search program, Nucleic Acids Res. 25: 3389-3402). All contig matches were analyzed for full-length putative sequences, and the longest clones representing the full-length putative contigs were fully sequenced. A sequence, GmSCLI (SEQ ID NO: 7) was identified from soy bean. The homology of the deduced amino acid sequence of GmSCLI (SEQ ID NO: 8) with the closest known prior art is indicated in Table 7. Figures 1, 2, and 3 show the relative homology and detailed alignment of the sequences of amino acids PpSCLI (SEQ ID NO: 2), PpSCL2 (SEQ ID NO: 4), PpSCL3 (SEQ ID NO: 6) and GmSCLI (SEQ ID NO: 8) with the sequences of other known members of the GRAS family. Table 5 Degree of amino acid identity and similarity of GmSCLI and a similar protein (a pairwise comparison was used: gap penalty: 10, gap extension penalty: 0.1, score matrix: blosum62) Table 6 Percentage identity between amino acid sequences of GmSCLI, PpSCLI, PpSCL2 and PpSCL3 (SEQ ID NOs: 2, 4, 6, and 8) Table 7 Percentual similarity between amino acid sequences of GmSCLI, PpSCLI, PpSCL2 and PpSCL3 (SEQ ID NOs: 2, 4, 6, and 8) Example 7 Engineering management of Arabidopsis plants by overexpressing genes of PpSCLI, PpSCL2, PpSCL3 and GmSCL1 Cloning of recombinant PpSCLI vectors, PpSCL2. PpSCL3 or GmSCLI Fragments containing PpSCLI, PpSCL2 or PpSCL3 were subcloned from the recombinant vector PCR2.1 TOPO by double digestion with restriction enzymes (see Table 6) according to the manufacturer's instructions. Subsequent fragments were removed from the agarose gel with a QIAquick gel extraction kit (Qiagen) according to the manufacturer's instructions and ligated into the binary vector containing the selectable marker gene, the constitutive promoter and the terminator. Transformation of Aqrobacterium Recombinant vectors were transformed into Agrobacterium tumefaciens C58C1 and PMP90 according to standard conditions (Hoefgen and Willmitzer, 1990). Transformation of plants A. thaliana ecotype C24 plants were grown and transformed according to standard conditions (Bechtold, 1993, Acad Sci Paris, 316: 1194-1199, Bent et al., 1994, Science 265: 1856-1860 ). Control of transformed plants T1 plants were controlled for their resistance to the selection agent conferred by the selectable marker gene, and T1 seeds were harvested. The T1 seeds were sterilized according to standard protocols (Xiong et al., 1999, Plant Molecular Biology Reporter 17: 159-170). Seeds were plated on ½ Murashige and Skoog (MS) media (Sigma-Aldrich) pH 5.7 with KOH, 0.6% agar and supplemented with 1% sucrose, 0.5 g / L acid 2- [N-morpholino] ethanesulfonic acid (MES) (Sigma-Aldrich), 50-150 pg / ml selection agent, 500 pg / ml carbenicilane (Sigma-Aldrich) and 2 μg / ml benomyl (Sigma-Aldrich). Seeds were plated for four days at 4 ° C. The seeds germinated in a climatic chamber at an ambient temperature of 22 ° C and a luminous intensity of 40 ~ -1 micromoles m (white light; Philips TL 65W / 25 fluorescent tube) and 16 hours of light and 8 hours of darkness. Transformed seedlings were selected after 14 days and transferred to plates with ½ MS medium pH 5.7 with KOH, 0.6% agar supplemented with 0.6% agar, 1% sucrose, 0.5 g / L of MES (Sigma-Aldrich), and 2 μg / ml of benomyl (Sigma-Aldrich), and allowed to recover for five to seven days. Control of growth under limited water conditions T1 plants were controlled for resistance to the selection agent conferred by the selectable marker gene and the seeds were collected. Seeds T2 and T3 were seeds controlled for resistance to the selection agent conferred by the selectable marker gene in plaques, and positive plants were transplanted to the soil and allowed to grow in a growth chamber for 3 weeks. The soil moisture was maintained during all this time in approximately 50% of the maximum capacity of the soil to maintain the water. The total water loss (transpiration) by the plant during this time was measured. After three weeks, all aerial plant material was collected, dried at 65 ° C for 2 days and weighed. The results are shown in Tables 8, 9, 10 and 11. The ratio of aerial dry weight of the plant to the use of water by the plant is the Efficiency of water use (WUE). Table 8 below shows the average WUE, the standard error for WUE, the dry weight of the plant (DW), and the standard error for DW for PpSCLI (SEQ ID NOs: 1 and 2) that overexpress plants, controls wild-type and transgenic vector controls alone. The information comes from approximately 50 plants per genotype, 5 plants from 10 independent transgenic lines and 4 independent experiments. Table 8 The above information is summarized in Table 9 below, presenting the percentage difference of the controls of the vector alone and of the wild type for PpSCLI (SEQ ID NO: 2) overexpressing plants. The data shows that the PpSCLI plants (SEQ ID NO: 2) have a significant increase in DW and WUE, compared to the controls. Plants that overexpress PpSCLI showed an approximate increase of 23-33% in dry weight compared to controls, and an approximate increase of 10-12% in water use efficiency compared to controls.

Table 9 Table 10 presents WUE and DW for independent transformation events (lines) for transgenic plants overexpressing PpSCLI (SEQ ID NO: 2) and PpSCL2 (SEQ ID NO: 4). We present the minimum square averages and the standard errors of a line compared to the wild type controls of an analysis of variance. We also present the percentage increase of wild-type control plants for WUE and DW for PpSCLI (EST 386) and PpSCL2 (EST 166) that overexpress plants. Table 10 Table 1 1 represents WUE for independent transformation events (lines) for PpSCL3 (SEQ ID NO: 6). The average and standard errors of a line are listed in comparison with transgenic controls. In addition, an analysis of variance is presented that compares all transgenic control lines with all PpSCL3 (SEQ ID NO: 6) that overexpress lines for WUE, which show minimum square averages, standard errors and significance value (p). The average increase in the combined analysis of PpSCL3 (SEQ ID NO: 6) is also presented as a percentage stimulation, in comparison with the transgenic control. Table 11 EXAMPLE 8 Genetic manipulation of stress-tolerant corn plants by overexpressing SLSRP genes Agrobacterium cells containing the genes and the maize ahas gene were cultured in the same plasmid in YP medium supplemented with suitable antibiotics for 1-3 days. A loop of Agrobacterium cells was collected and suspended in 2 ml of M-LS-002 medium (LS-inf) and the tube containing the Agrobactium cells was left on a shaker for 1-3 hours at 1,200 rpm. Corn ears [genotype J553x (HIIIAxA188)] were collected 7-12 days after pollination. The ears were sterilized in 20% Clorox solution for 15 min, followed by careful rinsing with sterile water. Immature embryos with a size of 0.8-2.0 mm were divided in the tube containing the Agrobacterium cells in LS-inf solution. Agro-infection was carried out keeping the tube horizontal in the laminar cover at room temperature for 30 min. The agro-infection mixture was poured into a plate containing the co-culture medium (M-LS-011). Once the liquid agro-solution was removed with a pipette, the embryos were plated in the co-culture medium with the scutellum side up and cultured in the dark at 22 ° C for 2-4 days. The embryos were transferred to medium M-MS-101 without selection. 7-10 days later, the embryos were transferred to M-LS-401 medium containing 0.75uM imazethapyr and cultured for 4 weeks to select transformed callus cells. Regeneration of the plants was initiated by transferring the resistant calli to medium M-LS-504 supplemented with 0.75 μ? of imazetapir and were grown in light at 26 ° C for two or three weeks. The regenerated shoots were then transferred to a box for root formation with medium M-MS-607 (0.5 μ? Imazethapyr). The seedlings with roots were transferred to the pot mix and were grown in a growth chamber for a week, then transplanted into larger pots and kept in the greenhouse until maturity.

Claims (1)

CLAIMS 1. A transgenic plant transformed with a nucleic acid encoding a polypeptide, characterized in that the nucleic acid comprises a polynucleotide sequence selected from the group consisting of: a. a polynucleotide sequence encoding a polypeptide as defined in SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6 or SEQ ID NO: 8; b. a polynucleotide sequence as defined in SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5 or SEQ ID NO: 7¡ c. a polynucleotide sequence that encodes a polypeptide having at least 60% sequence identity with the full length polypeptide as defined in SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6 or SEQ ID NO : 8; and d. a polynucleotide sequence that hybridizes under stringent conditions at least one sequence selected from the group consisting of the sequence of full length polynucleotides of a) or b) above and the full length complement of the polynucleotide sequence of a) or b) above, wherein the stringent conditions comprise hybridization in a 6X solution of sodium chloride / sodium citrate (SSC) at 65 ° C; wherein the expression of the polynucleotide in the plant results in an increase in the plant tolerance to drought stress, as compared to a wild type variety of the plant. 2. The transgenic plant according to claim 1, characterized in that the expression of the polynucleotide in the plant results in increased growth in the plant under limited water conditions. 3. The transgenic plant according to claim 2, characterized in that the highest growth in limited water conditions is due to the greater efficiency of water use in the plant (WUE). 4. The transgenic plant according to claim 3, characterized in that the greater WUE is due to the greater dry weight in the plant. 5. The transgenic plant according to claim 1, characterized in that the plant is a monocot. 6. The transgenic plant according to claim 1, characterized in that the plant is a dicot. The transgenic plant according to claim 1, characterized in that the plant is selected from the group consisting of corn, wheat, rye, oats, triticale, rice, barley, soya bean, peanut, cotton, rapeseed, canola , cassava, pepper, sunflower, tagetes, solanaceous plants, potatoes, tobacco, eggplant, tomato, Vicia species, peas, alfalfa, coffee, cocoa, tea, Salix species, oil palm, coconut, perennial grass, Trigograss, Canarygrass, Bromegrass, Wildrye Grass, Bluegrass, Orchardgrass, Alfalfa, Salfoin, Trefoil Birdsfoot, Alsike Clover, Red Clover and Sweet Clover. 8. The transgenic plant according to claim 1, characterized in that the plant is a whole plant, a plant cell, a part of the plant or a vegetable seed. The transgenic plant according to claim 2, characterized in that the plant is a whole plant, a plant cell, a part of the plant or a vegetable seed. The transgenic plant according to claim 3, characterized in that the plant is a whole plant, a plant cell, a part of the plant or a vegetable seed. eleven . The transgenic plant according to claim 4, characterized in that the plant is a whole plant, a plant cell, a part of the plant or a vegetable seed. 12. An isolated nucleic acid encoding a polypeptide, characterized in that the nucleic acid comprises a polynucleotide sequence selected from the group consisting of: a. a polynucleotide sequence encoding a polypeptide as defined in SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6 or SEQ ID NO: 8; b. a polynucleotide sequence as defined in SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5 or SEQ ID NO: 7; c. a polynucleotide sequence that encodes a polypeptide having at least 60% sequence identity with the full length polypeptide as defined in SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6 or SEQ ID NO : 8; and d. a polynucleotide sequence that hybridizes under stringent conditions to at least one sequence selected from the group consisting of the full length polynucleotide sequence of a) or b) above and the full length complement of the polynucleotide sequence of a) or b) above, wherein the stringent conditions comprise hybridization in a 6X solution of sodium chloride / sodium citrate (SSC) at 65 ° C; wherein the polypeptide, when expressed in a plant, confers an increase in tolerance to drought stress to said plant. 13. A recombinant vector characterized in that it comprises the isolated nucleic acid according to claim 12. 14. The recombinant vector according to claim 13, characterized in that it is an expression vector that also comprises one or more regulatory sequences. A method for producing a transgenic plant comprising a nucleic acid encoding a polypeptide, characterized in that it comprises the steps of: transforming a plant cell with an expression vector comprising the nucleic acid and generating the plant from the plant cell transgenic expressing the polypeptide; wherein overexpression of the polypeptide in the plant results in an increase in tolerance to drought stress in the plant, as compared to a variety of wild-type plant, and wherein the nucleic acid comprises a polynucleotide sequence selected from the group consisting of in: a. a polynucleotide sequence encoding a polypeptide as defined in SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6 or SEQ ID NO: 8; b. a polynucleotide sequence as defined in SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 5 or SEQ ID NO: 7; c. a polynucleotide sequence that encodes a polypeptide having at least 60% sequence identity with the full length polypeptide as defined in SEQ ID NO: 2, SEQ ID NO: 4, SEQ ID NO: 6 or SEQ ID NO : 8; and d. a polynucleotide sequence that hybridizes under stringent conditions to at least one sequence selected from the group consisting of the full length polynucleotide sequence of a) or b) above and the full length complement of the polynucleotide sequence of a) or b) above, wherein the stringent conditions comprise hybridization in a 6X solution of sodium chloride / sodium citrate (SSC) at 65 ° C. 16. A method for growing plants in an agricultural locus, characterized in that it comprises obtaining the transgenic plant according to claim 1, and cultivating said plant in the agricultural locus. 17. An animal feed, an edible, cosmetics or pharmaceutical agents characterized in that they have been prepared from the transgenic plant according to claim

1.