JP2007222129A - Method for producing environmental stress resistant plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new means for the molecular breeding of a plant having improved resistance to environmental stress such as drought stress. <P>SOLUTION: At1g13990 gene or At4g01026 gene in Arabidopsis thaliana is transferred and expressed in a plant to impart the plant with resistance to environmental stress such as drought stress. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a vector comprising a gene encoding a protein that confers environmental stress resistance to a plant, a method for producing an environmental stress resistant plant using the vector, and a gene encoding a protein that confers environmental stress resistance to the plant. The present invention relates to a method for screening genes that confer resistance to environmental stress and plants.

  Explosive population growth is expected due to the decline in mortality due to medical advances. Compared to the high growth rate of the population, the growth rate of food to support it is far below, and measures to increase food production are urgently needed. However, the expansion of farmland due to increased food production is limited because it causes environmental destruction. As a solution, a useful gene is introduced using biotechnology, and it is expected to produce a plant that grows even under dry conditions that are currently difficult to grow. So far, reports of experimental examples in which drought tolerance of plants has been improved by genetic recombination include those with enhanced oligosaccharide synthesis such as trehalose (Non-patent Document 1), galactinol, raffinose (Non-patent Document 2) and peroxidase genes (Non-Patent Document 3). Moreover, as an example of increasing the drought tolerance by inducing or activating the expression of a drought-inducing gene, a method using a transcription factor (Non-patent Document 4) and a method using a phosphorylase (Non-Patent Document 5) have been reported.

Garg AK et al., Proc. Natl. Acad. Sci. USA, vol.99, pp15898-15903, 2002 Taji T et al., Plant J., vol.29, pp417-426, 2002 Llorente F et al., Plant J., vol.32, pp13-24, 2002 Kasuga M et al., Nat Biotechnol., Vol.17, pp287-291, 1999 Umezawa T et al., Proc. Natl. Acad. Sci. USA, vol.101, pp17306-17311, 2004

There are several reports on molecular breeding of drought-tolerant plants as described above. However, molecular breeding of plants resistant to environmental changes such as drought is currently delayed in research and development due to the complexity of the molecular mechanism for obtaining that tolerance.
The present invention has been made under such a technical background, and an object of the present invention is to provide a new means for molecular breeding of plants with improved resistance to environmental stresses such as drought stress.

  In order to solve the above-mentioned problems, the present inventor first synthesized the plant hormone “abscisic acid (ABA)” which plays an important role in seed maturation, drying and salt stress in the chloroplast. Focusing on this fact, we attempted to search for a gene from among genes encoding chloroplast migration proteins. As a material for gene search, the Arabidopsis Genome Initiative, Nature vol.408, pp796-815, 2000) was used as a model experimental plant whose base sequence of the entire genome was determined. Using a program (Emanuelsson O et al., J. Mol. Biol., Vol.300, pp1005-1016, 2000) that predicts the transition signal (transit peptide) to the chloroplast on the N-terminal side of the protein . It is very difficult in terms of time and labor to create a strain and transformant of the gene encoding the chloroplast protein, which is predicted to be about 3,500 encoded by the Arabidopsis genome, and to investigate the resistance to environmental stress. It is. Therefore, the present inventor narrowed down the target genes from several to several tens by integrating the Arabidopsis genome information and the expression profile analysis data, and investigated the stress resistance performance of these mutants and overexpressing organisms to A gene conferring resistance was identified.

The present invention has been completed based on the above findings.
That is, the present invention provides the following (1) to (9).

(1) A vector comprising a gene encoding the following protein (a), (b), (c), (d), (e), or (f):
(a) a protein represented by the amino acid sequence set forth in SEQ ID NO: 2,
(b) a protein that is represented by an amino acid sequence in which one or more amino acids are deleted, substituted, or added in the amino acid sequence set forth in SEQ ID NO: 2, and that imparts environmental stress tolerance to plants,
(c) A plant-derived protein encoded by a DNA that hybridizes under stringent conditions with DNA represented by the nucleotide sequence of SEQ ID NO: 1 or DNA complementary thereto, and imparts environmental stress resistance to the plant Protein,
(d) a protein represented by the amino acid sequence of SEQ ID NO: 4,
(e) a protein that is represented by an amino acid sequence in which one or more amino acids are deleted, substituted, or added in the amino acid sequence set forth in SEQ ID NO: 4, and that confers environmental stress resistance to plants,
(f) A plant-derived protein encoded by a DNA hybridized under stringent conditions with a DNA represented by the nucleotide sequence of SEQ ID NO: 3 or a DNA complementary thereto, and imparts environmental stress resistance to the plant Protein.

(2) A gene encoding the protein (a), (b), (c), (d), (e), or (f) in the plant by introducing the vector described in (1) into the plant A method for producing an environmental stress-tolerant plant characterized in that

(3) The method for producing an environmental stress resistant plant according to (2), wherein the plant is a cruciferous plant.

(4) The method for producing an environmental stress resistant plant according to (2) or (3), wherein the environmental stress is drought stress.

(5) An environmental stress-tolerant plant into which a gene encoding the following protein (a), (b), (c), (d), (e), or (f) is introduced and expressed:
(a) a protein represented by the amino acid sequence set forth in SEQ ID NO: 2,
(b) a protein that is represented by an amino acid sequence in which one or more amino acids are deleted, substituted, or added in the amino acid sequence set forth in SEQ ID NO: 2, and that imparts environmental stress tolerance to plants,
(c) A plant-derived protein encoded by a DNA that hybridizes under stringent conditions with DNA represented by the nucleotide sequence of SEQ ID NO: 1 or DNA complementary thereto, and imparts environmental stress resistance to the plant Protein,
(d) a protein represented by the amino acid sequence of SEQ ID NO: 4,
(e) a protein that is represented by an amino acid sequence in which one or more amino acids are deleted, substituted, or added in the amino acid sequence set forth in SEQ ID NO: 4, and that confers environmental stress resistance to plants,
(f) A plant-derived protein encoded by a DNA hybridized under stringent conditions with a DNA represented by the nucleotide sequence of SEQ ID NO: 3 or a DNA complementary thereto, and imparts environmental stress resistance to the plant Protein.

(6) The environmental stress resistant plant according to (5), wherein the plant is a cruciferous plant.

(7) The environmental stress resistant plant according to (5) or (6), wherein the environmental stress is drought stress.

(8) A screening method for a gene imparting environmental stress resistance, characterized by selecting a gene using the following (A) and (B) as an index:
(A) it is a gene encoding a chloroplast migration protein,
(B) A gene whose expression increases when abscisic acid is added or when environmental stress is applied.

(9) The screening method for a gene imparting resistance to environmental stress according to (8), wherein the environmental stress is at least one selected from the group consisting of low-temperature stress, drought stress, and salt stress.

  According to the present invention, it becomes possible to produce a plant exhibiting resistance to environmental stress such as drought stress. Such environmental stress-tolerant plants can grow even in a poor environment that cannot be grown by ordinary plants, and thus contribute to the expansion of farmland and increased production of food.

Hereinafter, the present invention will be described in detail.
The vector of the present invention is a gene encoding the following protein (a), (b), (c), (d), (e), or (f) (hereinafter these genes are referred to as “the present gene”). In some cases).

(a) a protein represented by the amino acid sequence set forth in SEQ ID NO: 2,
(b) a protein that is represented by an amino acid sequence in which one or more amino acids are deleted, substituted, or added in the amino acid sequence set forth in SEQ ID NO: 2, and that imparts environmental stress tolerance to plants,
(c) A plant-derived protein encoded by a DNA that hybridizes under stringent conditions with DNA represented by the nucleotide sequence of SEQ ID NO: 1 or DNA complementary thereto, and imparts environmental stress resistance to the plant Protein,
(d) a protein represented by the amino acid sequence of SEQ ID NO: 4,
(e) a protein that is represented by an amino acid sequence in which one or more amino acids are deleted, substituted, or added in the amino acid sequence set forth in SEQ ID NO: 4, and that confers environmental stress resistance to plants,
(f) A plant-derived protein encoded by a DNA hybridized under stringent conditions with a DNA represented by the nucleotide sequence of SEQ ID NO: 3 or a DNA complementary thereto, and imparts environmental stress resistance to the plant Protein.

  The proteins (a) and (d) are proteins encoded by genes named “At1g13990” and “At4g01026” contained in Arabidopsis thaliana, respectively. Although these genes are known genes, it has been revealed for the first time that they are involved in environmental stress tolerance.

  The proteins (b) and (e) are proteins in which mutations are introduced into the proteins (a) and (d) within a range that does not affect the function of imparting environmental stress tolerance. Such mutations include artificial mutations in addition to mutations that occur in nature. Examples of means for causing artificial mutation include site-directed mutagenesis (Nucleic Acids Res. 10, 6487-6500, 1982), but are not limited thereto. The number of mutated amino acids is not limited as long as the aforementioned function is not lost, but is usually within 30 amino acids, preferably within 20 amino acids, more preferably within 10 amino acids, most preferably Preferably it is within 5 amino acids. Whether the protein into which the mutation is introduced imparts environmental stress tolerance to the plant can be determined by introducing and expressing a gene encoding the protein in the plant and examining whether the plant exhibits environmental stress tolerance.

  The proteins (c) and (f) are proteins having the same functions as (a) and (d), which are obtained by utilizing hybridization between DNAs. The “stringent conditions” in the proteins (c) and (f) are conditions under which only specific hybridization occurs and non-specific hybridization does not occur. Such conditions are usually conditions such as hybridization at 37 ° C. and washing treatment at 37 ° C. with a buffer containing 1 × SSC and 0.1% SDS, preferably hybridization at 42 ° C. and 0.5 × Conditions such as washing at 42 ° C. with a buffer containing SSC and 0.1% SDS, more preferably hybridization at 65 ° C. and washing at 65 ° C. with a buffer containing 0.2 × SSC and 0.1% SDS This is the condition. DNA obtained by hybridization usually has high homology with the DNA represented by the nucleotide sequence shown in SEQ ID NO: 1 or SEQ ID NO: 3. High homology refers to homology of 60% or more, preferably 75% or more, more preferably 90% or more.

  The vector of the present invention may contain the present gene, but preferably also contains an appropriate promoter and the like and can express the gene in plants. In this case, as the promoter to be used, the cauliflower mosaic virus 35S promoter used in the examples can be exemplified, but in addition to that, the promoter of nopaline synthase gene (Pnos), the ubiquitin promoter derived from maize, derived from rice Other actin promoters, tobacco PR protein promoters, and the like can also be used.

An environmental stress resistant plant can be produced by introducing the vector of the present invention into a plant and expressing the gene.
As a method for introducing the vector of the present invention into a plant, a vacuum infiltration method using Agrobacterium can be exemplified, but besides that, the PEG-calcium phosphate method, the electroporation method, the liposome method, the party cardan method, It can also be introduced by a microinjection method or the like.

  The plant to be introduced is not particularly limited, and general seed plants can be introduced. Among the seed plants, it is particularly preferable to target dicotyledonous plants, and among dicotyledonous plants, cruciferous plants, solanaceous plants, legumes, cucurbits, sericaceae, asteraceae, mallow It is preferable to target plants, red crustaceae plants, myrtaceae plants, willow plants, and the like. Examples of the cruciferous plant include Arabidopsis, rapeseed, cabbage, cauliflower, broccoli, radish and the like.

  Only Arabidopsis thaliana has been experimentally confirmed to be able to impart environmental stress tolerance with this gene, but it is thought that imparting environmental stress tolerance with this gene can be applied to plants in general. This is due to the following reason. A gene similar to the At4g01026 gene, which is one of the present genes, is present in plants other than Arabidopsis thaliana, and also present in rice, a plant taxonically distant from Arabidopsis thaliana (FIGS. 10 and 11). . Therefore, genes similar to the At4g01026 gene are considered to exist widely in plants in general. In addition, these similar genes are considered to be involved in environmental stress tolerance like the At4g01026 gene. Therefore, it is considered that environmental stress resistance can be imparted to a plant by introducing into the plant a gene in which the At4g01026 gene or a partial sequence thereof has been changed. In addition, a gene similar to the At1g13990 gene, which is one of the genes, has been confirmed to exist only in rice at present (FIG. 9). However, considering that rice and Arabidopsis thaliana are particularly advanced in genome analysis, and that plants with similar genes are taxonomically distant from Arabidopsis thaliana, plants other than rice It is highly possible that a similar gene to the At1g13990 gene exists. Therefore, as in the case of the At4g01026 gene, it is considered that the introduction of a gene in which the At1g13990 gene gene or a partial sequence thereof is changed into a plant can impart environmental stress tolerance to the plant.

Examples of the environmental stress tolerance imparted by this gene include low temperature stress tolerance, salt stress tolerance, osmotic stress tolerance and the like in addition to drought stress tolerance.
In the present invention, a gene is selected using as an index (A) a gene encoding a chloroplast migration protein and (B) a gene whose expression increases when abscisic acid is added or when environmental stress is applied. The screening method of the gene which provides the environmental stress tolerance characterized by this is also included.

  Whether or not the protein is a chloroplast migration protein can be determined from the presence or absence of a transit peptide. Whether the expression increases when abscisic acid is added or when environmental stress is applied can be examined by a microarray or the like. Examples of environmental stresses to be screened include low temperature stress, drought stress, salt stress, osmotic stress resistance and the like.

  Hereinafter, the present invention will be described in more detail with reference to examples.

[Example 1] Search for genes encoding environmental stress-inducible chloroplast transfer protein It is predicted that the TargetP program will be involved in chloroplast transfer from all 27,000 Arabidopsis genes predicted to be Based on the amino acid sequence, 3,633 genes encoding chloroplast translocation proteins in the Arabidopsis genome were selected. Next, these gene groups were expressed by dry / salt / low-temperature environmental stress treatment and ABA treatment, which were obtained from the results of about 7,000 full-length cDNA microarrays analyzed by RIKEN. Seki et al. 2002 Plant J 31, pp279-292; Seki et al. 2002 Funct Integr Genomics 2, pp292-300), 54 candidate chloroplast-related genes related to resistance to environmental stress were obtained. . Furthermore, these and the data of the transposon Ds insertion mutant line prepared in the RIKEN laboratory (Ito et al. 2002 Plant Physiol 129, pp1695-1699; Kuromori et al. 2004 Plant J 37, pp897-905; Ito et al. 2005 Plant Cell Physiol 46, pp1149-1153), 10 genes having mutants with Ds inserted therein were obtained (FIG. 1).

  Of these 10 genes, 5 genes were found to have different Ds insertion positions as a result of the analysis in Example 3 below, so the remaining 5 genes were analyzed later. It was. Table 1 shows information on the five genes targeted for analysis.

  Note that the “At4g01026” gene was annotated as At4g01020 at the time of analysis by the present inventor and was a chloroplast migration protein, but the current number At4g01026 was updated as the database was updated in August 2005. It is no longer a chloroplast transition protein.

[Example 2] Confirmation of stress inducibility by RNA blot The RNA sample used was a low-temperature treatment (stored at 4 ° C) of a plant grown for 3 weeks in a plant growth medium, and a dry treatment (from the growth medium on an empty plastic petri dish). Transplanted and stored), salt treatment (stored in 250 mM NaCl aqueous solution), ABA treatment (stored in 100 μM ABA aqueous solution) for a specified time (0, 1, 2, 5, 10, 24 hours) and then ISOGEN reagent (Nippon Gene) Extracted). Ten full-length cDNAs of 10 genes were labeled with [α- ³² P] dCTP and used as probes. Each sample RNA (10 μg / well) was subjected to agarose gel electrophoresis, and it was confirmed by RNA blot that expression was induced in response to environmental stress in the same manner as microarray data. FIG. 2 shows the expression status of the five genes to be analyzed.

  As shown in FIG. 2, the At1g13990 gene and At4g01026 gene have been observed to increase RNA levels in all treatments except low-temperature treatment, and these two genes are predicted to play an important role in environmental stress tolerance. It was. The nucleotide sequence of At1g13990 gene and the amino acid sequence of the protein encoded by it are shown in SEQ ID NOs: 1 and 2, respectively. In addition, the nucleotide sequence of the At4g01026 gene and the amino acid sequence of the protein encoded by it are shown in SEQ ID NOs: 3 and 4, respectively.

[Example 3] Collection and selection of gene mutants and production of overexpressed bodies In order to examine the function of stress-related genes in selected chloroplasts in plant individuals, selection of mutants with disrupted genes and excessive gene expression The overexpressed body was expressed.
Mutants are collected by collecting plant seeds with transposon Ds inserted into the target gene from the tag line created by RIKEN, and selecting homo mutants by segregation ratio analysis and PCR analysis. Obtained.

  To create an overexpressing body, construct a construct linked downstream of the cauliflower mosaic virus 35S promoter (CaMV35S) that constantly and strongly expresses the target gene, and introduce it into Agrobacterium GV3101. Transformed into wild-type Arabidopsis thaliana. When transformants were selected using a selection marker (kanamycin / cefotaxime), multiple individuals were obtained for each of the five genes to be analyzed. As in Example 2 above, it was confirmed by RNA blot that the target gene was overexpressed in each individual. The result is shown in FIG.

  As shown in FIG. 3, the expression of the target gene was confirmed in most individuals. For each gene, one individual that appears to be the most strongly expressed was selected (individual numbered circles in the figure) and used in the subsequent experiments.

[Example 4] Phenotypic observation of mutants and overexpressing mutants and overexpressing mutants can be seen in the color, shape, and size of leaves compared to wild type plants on culture plates or in potted plants under normal growth conditions. There was no significant change such as (Fig. 4). Plants overexpressing genes involved in the stress response often show fertility such as short stature and narrow branches, but the overexpression of the present invention did not show such a phenotype. This seemed to be useful in breeding.

[Example 5] Drying tolerance test of gene mutants and overexpressing bodies Mutants and overexpressing bodies were cultivated on a plant culture medium plate for 2 weeks, transplanted to soil and grown for 1 week, and then subjected to a drying treatment. After about 2 weeks of drying without water, the water was reabsorbed and the survival rate was measured after another week of treatment. This experiment was repeated and calculated from the survival rate of a total of 15 plants. In addition, the survival rate was similarly measured about the plant which introduce | transduced the AtNCED3 gene known to provide drought tolerance as Positive Control. FIG. 5B shows the survival rates of mutants and overexpressing mutants of At1g13990 gene and At4g01026 gene. Moreover, the external appearance photograph of the variant after drying and a reabsorption process and an overexpressing body is shown to FIG. 5A.

  As shown in FIG. 5, with respect to the At1g13990 gene, the mutant was weaker in drought than the wild type, and the overexpressed mutant showed considerably stronger drought tolerance than the wild type. For At4g01026, the mutant was wild. It was weaker than the type, and the overexpressing body showed a slightly stronger drought tolerance than the wild type.

[Example 6] Elucidation of the mechanism for imparting drought tolerance In order to investigate the cause of obtaining the drought tolerance, the amount of transpiration of the plant was measured. At1g13990 gene, At4g01026 gene mutant and overexpressing body and wild-type plant were transferred from the growth medium onto a dry filter paper and left in a clean bench for a predetermined time (0, 10, 20, 30, 40, 50 , 60, 90, 120, 180 minutes), and the amount of transpiration was detected by measuring the weight of the plant. The result is shown in FIG.
As shown in FIG. 6, the water deficiency rate was higher in the mutant compared to the wild type, whereas the water deficiency rate was lower in the overexpressing body compared to the wild type.

  Transpiration is a phenomenon in which water in the plant body turns into water vapor and goes out into the air, and is mainly performed in the pores of the leaves. Wild-type plants are known to have a function of keeping pores closed during drying to maintain moisture in the plant body. When the opening and closing of the pores was examined with an optical microscope, the normal pores were completely open in the wild type and mutants, but many of them were slightly closed in the overexpressing body (FIG. 7). Moreover, when the plant body was treated with 5 μM ABA, 1h and dried, the pores of the mutant continued to be open compared to the wild type, whereas the overexpressed body was completely closed (FIG. 7). This is thought to be because both genes are involved in pore closure, and the mechanism of acquiring resistance in the drying process is due to the small amount of transpiration emitted from the pores.

[Example 7] Functional analysis of genes
The At1g13990 gene and At4g01026 gene have never been reported so far, and their functions are unknown. In order to confirm that the proteins (PA, PB) encoded by these two genes (At1g13990, At4g01026) migrate to chloroplasts, full-length cDNAs of PA and PB and synthetic green fluorescent protein (sGFP) under the CaMV35S promoter. A construct (p35S: PA-sGFP, p35S: PB-sGFP) in which the gene was linked was prepared and introduced into tobacco leaves with a perectulgan (PDS-1000 / He; Bio-Rad). These constructs allow the expression of the fusion protein of PA-sGFP and PB-sGFP in the introduced plant cells, and the localization of the target protein can be examined by observing the sGFP fluorescence signal. When cells transfected with p35S: PA-sGFP, p35S: PB-sGFP and control p35S: sGFP vector were observed with a confocal laser microscope (Zeiss), the sGFP signal was green in the cells transfected with p35S: PA-sGFP. In contrast to the autofluorescence of the body (middle of Fig. 8), cells transfected with p35S: PB-sGFP show sGFP signal throughout the cytoplasm, similar to those transfected with the control p35S: sGFP vector (upper row of Fig. 8). (Lower row in FIG. 8). This suggests that PA has a transit peptide necessary for chloroplast migration and works in the chloroplast, whereas PB works in the cytoplasm.

  The gene that is thought to encode the protein chloroplast protein PA has high homology in rice (O. sativa) (Fig. 9), but has high homology in Arabidopsis and other animals and plants. There was no homologue. On the other hand, genes that are thought to encode cytoplasmic protein PB have members homologous to Arabidopsis thaliana, and genes with high homology to rice, maize, pepper, and peas (FIGS. 10 and 11). ). These genes were similar to the Bet v I allergen and PR10-like sequences associated with the pathogen toxins.

The figure which represented the selection process of Example 1 typically. The figure which shows the result of having confirmed the expression of the gene after an environmental stress process by RNA blot. The figure which shows the result of having confirmed the expression of the target gene in the overexpression body selected by the selection marker by RNA blot. Appearance photograph of mutant (KO) and overexpression (OX) of each gene. Appearance photograph (A) of At1g13990 gene, mutant (KO) and overexpression body (OX) of At4g01026 gene, and figure showing survival rate after drying treatment (B). The figure which shows the time-dependent change of the water deficiency rate of the mutant (KO) of an At1g13990 gene and an At4g01026 gene, an overexpression body (OX), and a wild type plant body (WT). Optical micrographs around the pores of At1g13990 gene, At4g01026 gene mutant (KO) and overexpressing body (OX). A confocal laser micrograph of a cell into which a fusion gene of At1g13990 gene, At4g01026 gene and green fluorescent protein gene has been introduced. The figure which shows the amino acid sequence of the protein which At1g13990 gene codes, and the protein contained in rice. The figure which shows the amino acid sequence of the protein which At4g01026 gene codes, and the protein similar to it. The figure which shows the molecular phylogenetic tree of an At4g01026 gene and a gene similar to it.

Claims (9)

A vector comprising a gene encoding the following protein (a), (b), (c), (d), (e), or (f):
(a) a protein represented by the amino acid sequence set forth in SEQ ID NO: 2,
(b) a protein that is represented by an amino acid sequence in which one or more amino acids are deleted, substituted, or added in the amino acid sequence set forth in SEQ ID NO: 2, and that imparts environmental stress tolerance to plants,
(c) A plant-derived protein encoded by a DNA that hybridizes under stringent conditions with DNA represented by the nucleotide sequence of SEQ ID NO: 1 or DNA complementary thereto, and imparts environmental stress resistance to the plant Protein,
(d) a protein represented by the amino acid sequence of SEQ ID NO: 4,
(e) a protein that is represented by an amino acid sequence in which one or more amino acids are deleted, substituted, or added in the amino acid sequence set forth in SEQ ID NO: 4, and that confers environmental stress resistance to plants,
(f) A plant-derived protein encoded by a DNA hybridized under stringent conditions with a DNA represented by the nucleotide sequence of SEQ ID NO: 3 or a DNA complementary thereto, and imparts environmental stress resistance to the plant Protein.   A vector according to claim 1 is introduced into a plant, and a gene encoding the protein (a), (b), (c), (d), (e), or (f) is expressed in the plant. A method for producing an environmental stress resistant plant characterized by the above.   The method according to claim 2, wherein the plant is a cruciferous plant.   The method for producing an environmental stress resistant plant according to claim 2 or 3, wherein the environmental stress is drought stress. An environmental stress-tolerant plant into which a gene encoding the following protein (a), (b), (c), (d), (e), or (f) is introduced and expressed,
(a) a protein represented by the amino acid sequence set forth in SEQ ID NO: 2,
(b) a protein that is represented by an amino acid sequence in which one or more amino acids are deleted, substituted, or added in the amino acid sequence set forth in SEQ ID NO: 2, and that imparts environmental stress tolerance to plants,
(c) A plant-derived protein encoded by a DNA that hybridizes under stringent conditions with DNA represented by the nucleotide sequence of SEQ ID NO: 1 or DNA complementary thereto, and imparts environmental stress resistance to the plant Protein,
(d) a protein represented by the amino acid sequence of SEQ ID NO: 4,
(e) a protein that is represented by an amino acid sequence in which one or more amino acids are deleted, substituted, or added in the amino acid sequence set forth in SEQ ID NO: 4, and that confers environmental stress resistance to plants,
(f) A plant-derived protein encoded by a DNA hybridized under stringent conditions with a DNA represented by the nucleotide sequence of SEQ ID NO: 3 or a DNA complementary thereto, and imparts environmental stress resistance to the plant Protein.   The plant according to claim 5, wherein the plant is a cruciferous plant.   The environmental stress-resistant plant according to claim 5 or 6, wherein the environmental stress is drought stress. A screening method for a gene imparting environmental stress resistance characterized by selecting a gene using the following (A) and (B) as an index;
(A) it is a gene encoding a chloroplast migration protein,
(B) A gene whose expression increases when abscisic acid is added or when environmental stress is applied.   The method for screening a gene imparting resistance to environmental stress according to claim 8, wherein the environmental stress is at least one selected from the group consisting of low temperature stress, drought stress, and salt stress.