Application of calcium-dependent protein kinase Ocpk in improving sheath blight resistance of rice

Abstract

The invention relates to the field of plant genetic engineering, and discloses application of calcium-dependent protein kinase Ocpk in improving sheath blight resistance of rice. The invention provides a rice susceptible gene OsCPK4 mutant mrm1, and after resistance identification, the rice susceptible gene OsCPK4 mutant mrm1 is found to have remarkable resistance to common rice disease sheath blight. The nucleotide sequence of the rice susceptible gene OsCPK4 is as shown in SEQ ID NO.1. The invention also provides a recombinant expression vector for expressing the rice susceptible gene OsCPK4. The invention also provides an engineering strain of the overexpression rice susceptible gene OsCPK4. The recombinant expression vector of the plant susceptible gene OsCPK4 provided by the invention can be used for transforming a rice plant through an engineering strain and increasing the expression quantity of the rice susceptible gene OsCPK4, so that the rice plant obtains the susceptible character of common rice disease sheath blight. The invention provides a new target gene resource for designing rice disease-resistant gene engineering for inducing to generate disease resistance, so as to reduce the cost of researching and developing rice disease-resistant biological materials, and has important practical application value.

Description

Technical Field

[0001] The patented technology of this invention relates to the field of plant biotechnology, and specifically to the application of calcium-dependent protein kinase Oscpk in improving rice resistance to sheath blight. Background Art

[0002] The spread of rice diseases poses a threat to food security. Therefore, breeding higher-quality, disease-resistant rice varieties is urgent. Rice sheath blight is a fungal disease caused by the necrotrophic fungus Rhizoctonia solani. When it strikes, rice sheath blight can cause a 10%-30% yield reduction, and in severe cases, losses can reach 40%, severely impacting rice production.

[0003] During their growth, plants are attacked by a variety of pathogens. There are many types of plant pathogens, including viruses, bacteria, fungi, and nematodes. Pathogen invasion of plants leads to two results: (1) the pathogen successfully reproduces in the host plant, causing related diseases; (2) the host plant produces a disease resistance response, killing the pathogen or preventing its growth. Rice is one of the largest food crops in the world. Infection by pathogens can lead to a significant drop in rice yield. Therefore, finding disease-resistant germplasm and using resistance gene resources to improve plant disease resistance is the fundamental way to prevent diseases while protecting the environment. Plant disease resistance is a complex process regulated by multiple genes. Genes involved in plant disease resistance are divided into two categories: (1) disease resistance genes, also known as R (resistance) genes, and (2) disease resistance-related genes. According to current understanding of the function of disease resistance genes, the products of these genes mainly act as receptors, interacting directly or indirectly with pathogen proteins to initiate disease resistance signal transduction pathways in plants. Disease resistance genes mediate strong disease resistance and are good gene resources. However, the use of disease-resistant genes to improve plant resistance is limited due to the following reasons: (1) The resources of disease-resistant genes are limited. For example, there are currently fewer than 30 disease-resistant genes known to resist the important rice disease, bacterial leaf blight, and fewer than 10 disease-resistant genes known to resist another important rice disease, sheath blight; (2) Modifying plants with disease-resistant genes will lead to changes in other physiological indicators of the plants.

[0004] In addition, rice plant height is also an important regulatory trait in rice breeding. Reducing rice plant height will effectively prevent rice lodging, thereby increasing rice yield.

[0005] Therefore, it is necessary to provide an effective means to improve the resistance to rice sheath blight. Summary of the Invention

[0006] To solve the above-mentioned technical problems existing in the prior art, the present application provides the application of calcium-dependent protein kinase Oscpk in improving rice resistance to sheath blight. Specifically, ethyl methanesulfonate (EMS) was used to construct a Nipponbare (NIP) background mutagenesis library, and after inoculation with rice sheath blight (Rice sheath blight) physiological race NJ-2, phenotypic identification and statistics were performed to screen out the sheath blight-resistant rice material mrm1 (multiple disease resistance mutant 1) with a mutation in the calcium-dependent protein kinase gene Oscpk. After inoculation experiments with bacterial blight and rice blast and phenotypic identification of the material, it was confirmed that the material had significantly enhanced resistance to sheath blight pathogens, demonstrating that mrm1 plays an important role in rice resistance to sheath blight.

[0007] The specific technical solutions of the present invention are as follows:

[0008] The first purpose of the present application is to provide a rice calcium-dependent protein kinase gene OsCPK4, the nucleotide sequence of which is shown in SEQ ID NO.1.

[0009] The second purpose of the present application is to provide a protein encoded by the aforementioned rice calcium-dependent protein kinase gene OsCPK4, the amino acid sequence of the protein encoded by the OsCPK4 gene is shown in SEQ ID NO.2.

[0010] The third object of the present application is to provide a mutant of the rice OsCPK4 gene, wherein the mutant has a 60 bp deletion at 720 bp of the nucleotide sequence shown in SEQ ID NO.1.

[0011] The nucleotide sequence of the mutant is shown in SEQ ID NO.3.

[0012] The fourth object of the present application is to provide an overexpression vector containing the aforementioned rice OsCPK4 gene;

[0013] Preferably, the overexpression vector is obtained by using NIP gDNA as a template, amplifying OsCPK4-FLAG-F shown in SEQ ID NO.4 and OsCPK4-FLAG-R shown in SEQ ID NO.5, and ligating the amplified product into the EcoRI and BamHI restriction sites of the pCAMBIA 1305.1-3xFLAG vector.

[0014] The fifth objective of the present application is to provide the use of the aforementioned rice calcium-dependent protein kinase gene OsCPK4 in regulating rice sheath blight and / or regulating rice plant growth.

[0015] Furthermore, overexpression of OsCPK4 can increase the sensitivity of rice to sheath blight and / or reduce rice plant height.

[0016] Furthermore, mutation or knockout of the OsCPK4 can improve resistance to rice sheath blight and / or reduce rice plant height.

[0017] The sixth object of the present application is to provide the use of the aforementioned rice OsCPK4 gene mutant in improving rice sheath blight resistance and / or reducing rice plant height.

[0018] Furthermore, the mutant of the rice OsCPK4 gene was transformed into rice to obtain the Oscpk4 mutant strain mrm1 with improved resistance to rice sheath blight and / or reduced rice plant height.

[0019] The seventh object of the present invention is to provide the use of the aforementioned overexpression vector in reducing the height of rice plants.

[0020] OsCPK4 encodes a calcium-dependent protein kinase whose activity is regulated by calcium ion concentration. Elevated cytoplasmic calcium ion concentration activates its protein kinase activity, which in turn phosphorylates downstream proteins. In this study, a mutant with lesion-like spots was identified in a population of Nipponbare (NIP) mutated with ethyl methanesulfonate (EMS). Inoculation of this mutant with rice sheath blight, rice blast, and bacterial leaf blight revealed significantly enhanced resistance to all three diseases. The mutant was named mrm1 (multiple disease resistance mutant 1). Positional cloning and transgenic complementation experiments demonstrated that mrm1 is located on rice chromosome 2 and encodes a calcium-dependent protein kinase. Plants exhibit broad-spectrum resistance to multiple races of sheath blight (NJ-2 and YN-7). An F2 mapping population was constructed by crossing the mrm1 mutant with an indica rice variety (Taichung Native 1, TN1). The target gene was ultimately localized to an approximately 780 kb region on the short arm of chromosome 2. Resequencing and semi-quantitative analysis revealed a 60-bp deletion in the sixth exon of the OsCPK4 gene in the mutant, along with decreased expression, confirming the gene as a mutant in mrm1. Inoculation of mrm1 with multiple physiological races of sheath blight revealed broad-spectrum resistance to the disease.

[0021] The benefits achieved by the present invention are:

[0022] The harm posed by crop diseases to global food security is immeasurable. Reducing the decline in food quality and quantity caused by crop diseases is a hot topic in agricultural production today. Breeding disease-resistant varieties is the best solution to addressing food security. This invention reveals for the first time the broad-spectrum resistance of rice OsCPK4 gene mutants to the common rice disease sheath blight. Furthermore, this invention also discovers for the first time that the rice OsCPK4 gene regulates rice plant height. Overexpressing or mutating this gene in rice can reduce rice plant height and prevent lodging. This invention provides an important basis for the breeding of new disease-resistant and high-yield rice varieties. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the developmental phenotype of the mutant mrm1, where:

[0024] Figure 1 A is the whole plant phenotype of mrm1 and wild type;

[0025] Figure 1 B is the plant height statistics of wild type and mrm1;

[0026] Figure 1 C is the grain length, width, and thickness phenotypes of the wild type and mrm1;

[0027] Figure 1 D is the number of grains per ear and fertility phenotype between the wild type and mrm1;

[0028] Figure 1 E is the spike phenotype of wild type and mrm1, Figure 1 F is the number of grains per ear of wild type and mrm1.

[0029] Figure 2 The sheath blight resistance phenotype of the mrm1 mutant is shown in Figure 1.

[0030] Figure 2 A is the whole plant phenotype of the wild type and mrm1 inoculated with the physiological race NJ-2 of sheath blight;

[0031] Figure 2 B is the single tiller phenotype of the wild type and mrm1 inoculated with the physiological race NJ-2 of sheath blight;

[0032] Figure 2 C is the statistics of lesion length of wild type and mrm1 inoculated with physiological race NJ-2 of sheath blight;

[0033] Figure 2 D is the whole plant phenotype of the wild type and mrm1 inoculated with the physiological race YN-7 of sheath blight;

[0034] Figure 2E is the single tiller phenotype of the wild type and mrm1 inoculated with sheath blight race YN-7;

[0035] Figure 2 F is the statistics of lesion length of wild type and mrm1 inoculated with the physiological race YN-7 of sheath blight.

[0036] Figure 3 For the cloning and identification of mrm1, wherein:

[0037] Figure 3 A is the process of constructing the positional clonal population;

[0038] Figure 3 B is a schematic diagram of a polymorphic marker;

[0039] Figure 3 C is a schematic diagram of the chromosomal interval precisely mapped;

[0040] Figure 3 D is the semi-quantitative detection of OsBAX expression;

[0041] Figure 3 E: The expression level of OsCPK4 was detected by semi-quantitative method.

[0042] Figure 4 Phenotypic statistics for complementation lines overexpressing CPK4-FLAG in the mrm1 background were obtained, where:

[0043] Figure 4 A is a whole-plant photo of NIP, mrm1, and four complementation lines;

[0044] Figure 4 B is the plant height statistics of NIP, mrm1 and four complementation lines;

[0045] Figure 4 C is a photo of the number of grains per ear of NIP, mrm1, and four complemented lines;

[0046] Figure 4 D is the statistics of the number of grains per ear of NIP, mrm1 and the four complemented lines.

[0047] Figure 5 The height phenotype statistics of plants overexpressing CPK4-FLAG in the NIP background, where:

[0048] Figure 5 A is a photograph of the whole plant overexpressing CPK4-FLAG in the NIP background;

[0049] Figure 5 B is the height statistics of plants overexpressing CPK4-FLAG in NIP background.

[0050] Figure 6The data are for the resistance to sheath blight of cells overexpressing CPK4-FLAG in the NIP background, where:

[0051] Figure 6 A is a photo of lesions 21 days after NIP and CPK4-FLAG were inoculated with the physiological race NJ-2 of sheath blight;

[0052] Figure 6 B is the statistics of lesion length 21 days after NIP, CPK4-FLAG inoculation of sheath blight race NJ-2;

[0053] Figure 6 C is a photo of lesions 21 days after NIP and CPK4-FLAG were inoculated with the physiological race YN-7 of sheath blight;

[0054] Figure 6 D is the statistics of lesion length 21 days after NIP, CPK4-FLAG inoculation of sheath blight race YN-7. DETAILED DESCRIPTION

[0055] The present invention is further explained below with reference to the following examples, but the examples do not limit the present invention in any form.

[0056] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with specific examples. The specific examples described herein are only used to explain the present invention and are not intended to limit the present invention. The reagents and instruments involved in the following examples are all commercially available unless otherwise specified, and the detection methods involved are all conventional methods unless otherwise specified.

[0057] Example 1: Rice sheath blight inoculation method and identification of disease resistance phenotype

[0058] The physiological subspecies NJ-2 of the sheath blight pathogen was isolated and purified by our laboratory from naturally diseased rice plants at the Baima base in Lishui District, Nanjing in 2020. The purified strains were named NJ-1 to NJ-5 according to the individual plant numbering during the isolation and purification process. Among them, the NJ-2 strain can cause brown lesions in the rice leaf sheaths after inoculation and produce brown sclerotia in the later stage of the disease. Morphological identification determined that it is the pathogen of rice sheath blight, Rhizoctonia solani.

[0059] Inoculate the sclerotia or hyphae of the physiological subspecies NJ-2 of the sheath blight fungus into the center of a culture dish containing 15 mL of potato dextrose (PDA) medium, and evenly spread 1 cm × 0.5 cm × 0.1 cm wood chips around the inoculation center. Three days later, the surface of the wood chips will be observed to be covered with white hyphae. Inoculate the rice during the peak tillering period. Use sterile pointed tweezers to pick up the wood chips covered with white hyphae and embed them into the inner side of the leaf sheath of the rice inverted third leaf. Take 5 tillers from different directions for each individual plant for inoculation. Investigate the disease situation after 21 days.

[0060] The results showed that when rice plants inoculated with sheath blight develop small, dark green, water-soaked spots with blurred edges on the leaf sheaths, which gradually expand to become oval or cloud-like, with a gray-green or gray-brown center. At low humidity, the center becomes light yellow or gray-white, with damaged tissue in the center becoming translucent and dark brown at the edges. In severe cases, several lesions fuse to form large, irregular, cloud-like spots, often causing the leaves to turn yellow and die.

[0061] Example 2: Acquisition and phenotypic identification of the Oscpk4 mutant strain mrm1

[0062] The Oscpk4 mutant line mrm1 was obtained by inoculating Nipponbare with ethyl methanesulfonate (EMS) and then inoculating mycelium of the physiological race NJ-2 of rice sheath blight to conduct phenotypic identification and screening. After multiple generations of self-pollination, the disease-resistant phenotype can be stably inherited. This mutant has obvious resistance to rice sheath blight, so it was named multiple disease resistance mutant 1 (mrm1). The statistics of its agronomic traits such as plant type, fruit set rate, and panicle type are as follows Figure 1 The plant height of the mutant strain mrm1 was significantly lower than that of the wild type.

[0063] In order to verify the disease resistance of the rice oscpk4 mutant line mrm1 to the common rice disease sheath blight, we used the hyphae of the sheath blight race NJ-2 and the sheath blight race YN-7 to inoculate rice seedlings about 10 weeks old in the field with wood chips. The disease incidence was statistically analyzed 20 days after inoculation. It was found that compared with the wild type, the mutant showed resistance to the sheath blight pathogen NJ-2 and YN-7 physiological races. It shows that the mutant can enhance the resistance of rice to multiple sheath blight physiological races. The results showed that compared with the wild type, the mutant showed stronger resistance to sheath blight. At the same time, the plant height of the mutant line mrm1 was significantly lower than that of the wild type. Figure 2 .

[0064] Compared with the wild type, this mutant has stronger resistance to sheath blight and effectively reduces plant height.

[0065] Example 3: Positional cloning of mrm1

[0066] In this experiment, the Oscpk4 mutant was cloned. DNA was extracted from the two parents of the gene mapping population, namely the aforementioned Oscpk4 mutant line mrm1 and the indica rice variety TN1. After the F2 generation segregating population was inoculated with the physiological race NJ-2 of sheath blight, 48 individual plants with the wild-type susceptible phenotype and the mutant resistant phenotype were extracted from the population based on the resistance-susceptibility phenotype. Equal amounts of DNA were mixed to construct disease-resistant and disease-susceptible pools. Molecular markers on 12 rice chromosomes preserved in the laboratory were used to perform polymorphism analysis on mrm1, TN1, the disease-resistant pool, and the disease-susceptible pool. Molecular markers linked to the disease-resistant phenotype gene were screened, and the target gene was preliminarily located in a certain interval. The japonica rice variety NIP and the indica rice variety TN1 were used as reference genomes. The polymorphic positions between the two varieties were searched on the RiceVarMap v2.0 website, and the chromosomal positions were selected for analysis. The start and end positions were set between the physical positions of the preliminarily located molecular markers, and finally the InDel marker sites were obtained. Sequences upstream and downstream of the marker site were downloaded from the website "Index Information." Primers were designed using the Primer 3 website to amplify a fragment encompassing the marker site, keeping the fragment length between 100 and 250 bp. After designing the InDel primers, the F2 mapping population was expanded and PCR amplified using the designed InDel marker primers. The amplified products were separated by electrophoresis on a 5% agarose gel, and the crossover rate at that marker in the F2 population was calculated based on the banding patterns revealed by gel electrophoresis. A lower crossover rate indicates closer proximity to the target gene. Polymorphic primers were then designed stepwise to gradually narrow the mapping interval, ultimately completing fine mapping. Using existing molecular markers in our laboratory that are polymorphic between indica and japonica rice, marker screening was performed in the NIP, TN1, R-pool, and S-pool. Finally, four molecular markers, STS-9, STS-10, STS-11, and STS-12, on the short arm of chromosome 2, were linked to the MRM1 gene.

[0067] Initial gene localization was performed using 110 disease-resistant individuals from the F2 mapping population. Four molecular markers on chromosome 2, STS-9, STS-10, STS-11, and STS-12, were PCR amplified in each of the 110 disease-resistant individuals and the two parents, and their genotypes were recorded. After counting the number of recombination exchanges, the gene was initially localized between markers STS-10 and STS-11.

[0068] In order to further narrow the positioning interval, based on the results of the initial positioning, we used NIP and TN1 as reference genomes, searched for the polymorphic position between the two varieties on chromosome 2 on the RiceVarMap v2.0 website, and obtained the two molecular markers Chr2-10 and Chr2-18. Subsequently, 180 disease-resistant plants were used to further expand the positioning group, and STS-10, STS-11, Chr2-10 and Chr2-18 were used to amplify the 180 disease-resistant plants and two parents of the positioning group, respectively, and the genotype and the number of recombinant exchanges were recorded. Finally, the gene was located in the approximately 780kb interval between the two molecular markers Chr2-10 and Chr2-18. The positioning process is as follows Figure 3 .

[0069] To further accelerate the localization of mrm1, we selected leaves from disease-resistant mrm1 mutants that exhibited a lesion-like phenotype after inoculation with NJ-2 in the field and performed whole-genome resequencing. The sequencing results were filtered using NGSQC Toolkit v2.3 to remove low-quality reads from the raw data. The filtered reads were then aligned to the reference genome (NIP) (RGAP 7.0) using the Burrows-Wheeler-Alignment Tool (BWA). After alignment, duplicate reads were removed using samtools rmdup. Then, samtools mpileup was used to identify SNPs and indels that differed between mrm1 and NIP, and functional annotation of the genes at these loci was performed.

[0070] The analysis revealed only two single-nucleotide polymorphisms (SNPs) and two deletions within the 780kb candidate interval. The first SNP occurred within 2kb upstream of a gene encoding a plastid division protein that regulates the accumulation and replication of chloroplast proteins. The second SNP was located far from both the left and right genes. The third SNP involved a deletion within the sixth exon of the gene. The fourth deletion occurred within 2kb upstream of the gene.

[0071] The gene with the exon deletion is the calcium-dependent protein kinase OsCPK4. Previous studies have reported that oscpk4 mutants exhibit enhanced resistance to bacterial blight and rice blast, and that OsCPK4 negatively regulates ROS production and PR gene expression. The upstream deletion encodes a protein containing a BAX transmembrane inhibitory motif, which is involved in regulating cell death. Based on the disease-resistant phenotype of the mutants, we believe that the two genes with the segmental deletions are candidate genes for the MRM1 gene.

[0072] Quantitative primers were designed to detect the expression of these two genes. Figure 3OsBAX gene expression remained unchanged in NIP and mrm1, while OsCPK4 gene expression was decreased in mrm1. Therefore, we identified OsCPK4 as a candidate gene for MRM1 and renamed the mrm1 mutant oscpk4-3. The sequence of the OsCPK4 mutant gene in oscpk4-3 is shown in SEQ ID NO. 3.

[0073] Example 4: Transformation of mrm1 with pCAMBIA 1305.1-OsCPK4-3xFLAG

[0074] To further verify whether OsCPK4 is a candidate gene for mrm1 and to explore the function of OsCPK4, we constructed the pCAMBIA 1305.1-OsCPK4-3xFLAG vector, using NIP gDNA as a template and OsCPK4-FLAG-F: tatgaccatgattacgaattcATATGTCAAATACTTTACACCATTCGTTC (SEQ ID NO. 4);

[0075] The full-length OsCPK4 gene and a 1.5 kb upstream fragment of OsCPK4-FLAG-R: caggtcgactctagaggatccCACAAGGGGTTGTGGATTTGGAGGT (SEQ ID NO. 5) were amplified and ligated into the GAATTC (EcoRI) and GGATCC (BamHI) restriction sites of the pCAMBIA1305.1-3xFLAG vector via homologous recombination to overexpress the OsCPK4 gene. The pCAMBIA 1305.1-3xFLAG vector is a plant expression vector based on the pCAMBIA1305.1 vector, modified to include a 3xFLAG tag sequence in the multiple cloning site (MCS). It can be purchased from: http: / / www.biovector.net / product / 425289.html.

[0076] The OsCPK4 overexpression vector was introduced into the homozygous mrm1 mutant via Agrobacterium transformation for genetic complementation. Using this transgenic technique, we obtained a total of 18 independent transgenic plants. PCR analysis revealed four transgenic-positive plants, while the remaining plants were transgenic-negative.

[0077] By inoculating the four positive plants of the T0 generation with the physiological race NJ-2 of sheath blight, the incidence of the disease was statistically analyzed and it was found that the susceptibility of these four positive plants was significantly higher than that of the mutant, and their susceptibility was restored to the NIP level. The plant height, number of grains per ear, and grain size of the T0 generation transgenic plants were statistically analyzed. It was found that there was no significant change in the complementation of transgenic plants compared with NIP. Figure 4 This indicates that OsCPK4 is a candidate gene for mrm1.

[0078] Example 5: Plant height and resistance identification of susceptible material OsCPK4-3xFLAG

[0079] Verify the resistance of the rice OsCPK4 overexpression line OsCPK4-3xFLAG to the common rice disease sheath blight. To test the resistance of OsCPK4-3xFLAG to sheath blight, we transformed the wild-type rice Nipponbare with the OsCPK4 overexpression vector pCAMBIA 1305.1-OsCPK4-3xFLAG constructed in Example 4 to obtain the overexpression line OsCPK4-3xFLAG. Compared with the wild-type, the plant height of OsCPK4-3xFLAG was significantly reduced. Figure 5 .

[0080] Rice seedlings about 10 weeks old in the field were inoculated with wood chips using the NJ-2 race of sheath blight preserved in the laboratory and the YN-7 race of sheath blight donated by Professor Zuo Shimin of Yangzhou University. Disease incidence was recorded 20 days after inoculation. It was found that compared with the wild type, the overexpression strain was both resistant and susceptible to the NJ-2 and YN-7 races of sheath blight pathogens. This suggests that the mutant can enhance rice resistance to multiple sheath blight races, such as Figure 6 .

[0081] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A rice calcium-dependent protein kinase gene OsCPK4, characterized in that: The nucleotide sequence of the gene OsCPK4 is shown in SEQ ID NO.

1.

2. The protein encoded by the rice calcium-dependent protein kinase gene OsCPK4 according to claim 1, characterized in that The amino acid sequence of the protein encoded by the OsCPK4 gene is shown in SEQ ID NO.

2.

3. A mutant of the rice OsCPK4 gene, characterized in that: The mutant has a 60 bp deletion at 720 bp of the nucleotide sequence shown in SEQ ID NO.

1.

4. An overexpression vector containing the rice OsCPK4 gene according to claim 1; preferably, the overexpression vector is obtained by amplifying OsCPK4-FLAG-F shown in SEQ ID NO. 4 and OsCPK4-FLAG-R shown in SEQ ID NO. 5 using NIP gDNA as a template, and ligating the amplified product into the EcoRI and BamHI restriction sites of the pCAMBIA 1305.1-3xFLAG vector.

5. Use of the rice calcium-dependent protein kinase gene OsCPK4 according to claim 1 in regulating rice sheath blight and / or regulating rice plant growth.

6. The use according to claim 5, characterized in that Overexpression of OsCPK4 can increase the sensitivity of rice to sheath blight and / or reduce rice plant height.

7. The use according to claim 5, characterized in that Mutation or knockout of the OsCPK4 can improve rice resistance to sheath blight and / or reduce rice plant height.

8. Use of the mutant of the rice OsCPK4 gene according to claim 3 in improving resistance to rice sheath blight and / or reducing rice plant height.

9. The use according to claim 7, characterized in that The mutant of the rice OsCPK4 gene is transformed into rice to obtain the Oscpk4 mutant strain mrm1 with improved rice sheath blight resistance and / or reduced rice plant height.

10. Use of the overexpression vector according to claim 4 in reducing the height of rice plants.

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