Application of OsMYBR17, a MYB transcription factor that promotes both tillering and panicle development, in improving rice yield

Abstract

The present invention belongs to the technical field of plant genetic engineering, and relates to the technical field of crop breeding, and specifically relates to an application of a MYB transcription factor OsMYBR17 gene that simultaneously promotes tillering and panicle development in increasing rice yield, wherein the protein encoded by the OsMYBR17 gene is a protein with an amino acid sequence as shown in SEQ ID NO.1; or it is a protein with equivalent activity obtained by replacing, substituting and / or adding one or more amino acids to the amino acid sequence as shown in SEQ ID NO.1. This technical solution has discovered for the first time a gene that simultaneously positively regulates tillering and panicle development, which can promote rice tillering, increase the number of rice tillers, the panicle length of a single panicle branch, the weight of a single panicle, and the number of panicle grains per panicle, thereby increasing rice yield. The overexpression of this gene can be applied to the genetic improvement of rice plant type and yield, creating conditions for increasing rice yield and cultivating rice with a new plant type.

Description

Technical Field

[0001] The invention belongs to the technical field of plant gene engineering and relates to the technical field of crop breeding, and specifically relates to the application of a MYB transcription factor OsMYBR17 gene that simultaneously promotes tillering and panicle development in improving rice yield. Background Art

[0002] Rice (Oryza sativa L.) is one of the most important food crops in the world, and its yield determines the food security of the whole world. The yield of rice is mainly determined by three agronomic traits, namely the number of panicles per plant, the number of grains per panicle and the weight of single grain. Among them, the number of panicles per plant is closely related to the tillering of rice. As a special branch containing panicles in monocotyledons, the formation of rice tillering can be mainly divided into two stages, namely the initiation of tillering buds and the elongation of tillering buds (O.Leyser, Regulation of shoot branching by auxin.8(2003):541-545.). Usually, the occurrence of rice tillering buds is mainly in the axils of each leaf on the main stem of rice, but not all tillering buds can form effective tillers, which affects the yield of rice per plant. Only the axillary buds located at the ungerminated base internodes can develop into effective tillers, which in turn produce effective panicles and affect the yield of rice per plant (Y. Wang, J. Li, The plant architecture of rice (Oryza sativa). Plant Molecular Biology, 59 (2005): 75-84.). Therefore, the final number of tillers of rice depends on the initial number of tillering buds and the number of panicle branch differentiation. Therefore, if you want to increase the yield of rice per plant, the most important thing is to increase the initial number of tillering buds and the number of panicle branch differentiation.

[0003] Tillering and panicle development are two independent developmental processes in rice, both of which can affect the final yield of rice. Previous studies have revealed many genes that have pleiotropic effects on rice tillering and panicle development, and these genes are co-regulated in different parts. For example, PAY1 plays an important role in the core pathway of rice panicle development, encoding a protein related to auxin transport, positively regulating the secondary branching of the panicle while negatively regulating rice tillering (L. Zhao, L. Tan, Z. Zhu, et al, PAY 1 improves plant architecture and enhances grain yield in rice, The Plant Journal. 83 (2015) 528-536.). IPA1 binds to DEP1 in the panicle to increase the number of branches, and binds to TB1 in the base to inhibit rice tillering, thereby regulating the rice plant architecture (G. Li, H. Zhang, J. Li, et al, Genetic control of panicle architecture in rice, Crop. J. 9 (2021) 590-597.). The Ghd8 gene in rice can regulate rice tillering, plant height, and panicle branch number at the same time, but the regulatory trends of this gene on tillering and panicle branching are opposite (WHYan, P. Wang, HX Chen, et al, A major QTL, Ghd8, plays spleiotropic roles in regulating grain productivity, plant height, and heading date in rice, Mol. Plant. 4 (2011) 319-330.). There are many other genes that regulate both panicle and tillering, including APO2 / RFL, RCN1, RCN2, and OsCOL13 (Y. Lu, M. Chuan, H. Wang, et al, Genetic and molecular factors in determining grain number per panicle of rice, Front. Plant Sci. 13 (2022).). However, these genes have opposite effects on the regulation of tillering and panicle development. Promoting tillering inhibits panicle development, and conversely promoting panicle development inhibits tillering. There are few reports of genes that simultaneously promote and regulate tillering and panicle development in rice.

[0004] Molecular breeding is the application of molecular biology technology to breeding, breeding at the molecular level, which is a breeding method different from traditional hybrid breeding. Molecular breeding includes transgenic breeding, which is a breeding method that applies genetic engineering to breeding work and introduces genes to cultivate new varieties with certain requirements. Transgenic breeding of rice to increase the number of initial tillering buds and the number of panicle branch differentiation is of great significance to increasing rice yield. However, in fact, most genes can only regulate rice tillering or panicle development. A few genes can achieve simultaneous regulation of rice tillering and panicle development, but the regulatory trends of the above two events are opposite. Such genes used in genetic breeding may have a negative impact on other traits while improving a certain trait, which is not desirable. In the practice of transgenic breeding, the selection of target genes for transgenic breeding is very critical. There is an urgent need to screen and study rice development-related genes in order to find genes that can simultaneously positively regulate rice tillering and panicle development, thereby obtaining a molecular breeding method that can significantly increase rice yield. Summary of the invention

[0005] The present invention intends to provide an application of the MYB transcription factor OsMYBR17 gene for simultaneously promoting tillering and panicle development in improving rice yield, so as to solve the technical problem in the prior art that it is difficult to increase rice yield by simultaneously promoting tillering and panicle development of rice plants.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] The application of OsMYBR17 gene in rice cultivation, the protein encoded by OsMYBR17 gene is a protein with an amino acid sequence as shown in SEQ ID NO.1; or it is a protein with equivalent activity obtained by replacing, substituting and / or adding one or more amino acids to the amino acid sequence as shown in SEQ ID NO.1.

[0008] The present solution also provides a rice planting method for increasing rice yield, in which the OsMYBR17 gene is overexpressed in rice plants; the nucleotide sequence of the OsMYBR17 gene is shown in SEQ ID NO.2.

[0009] The principles and advantages of this solution are:

[0010] After increasing the protein expression of the OsMYBR17 gene of rice plants, the number of tillers per rice plant, biomass, number of panicle branch differentiation, and number of rice grains are significantly increased at the same time, thereby increasing the yield per rice plant. Knockout of this gene simultaneously reduces the number of tillers per rice plant, biomass, and number of panicle branch differentiation, and plays a negative regulatory role in the yield per rice plant. Under the premise of not affecting the activity of the OsMYBR17 protein (i.e., not in the active center of the protein), those skilled in the art can perform various substitutions, additions, and / or deletions of one or more amino acids to the amino acid sequence shown in SEQ ID NO.1 to obtain an amino acid sequence with equivalent functions. Therefore, the OsMYBR17 protein also includes a protein with equivalent activity obtained by replacing, substituting, and / or adding one or more amino acids to the amino acid sequence shown in SEQ ID NO.1. In addition, considering the degeneracy of codons and the preference of codons of different species (e.g., performing synonymous mutations according to codon preference), those skilled in the art can use codons suitable for expression of specific species as needed.

[0011] The inventors cloned the cDNA sequence of the OsMYBR17 gene from rice Zhonghua 11 (ZH11). By constructing an OsMYBR17 gene overexpression vector and introducing the overexpression vector into Zhonghua 11 (ZH11), OsMYBR17 gene overexpression plants were obtained, and the length of the tiller buds of a single rice plant, the biomass, and the number of panicle branch differentiation, etc., were significantly improved compared with Zhonghua 11. By constructing a gene knockout vector of the OsMYBR17 gene and introducing the knockout vector into Zhonghua 11 (ZH11), OsMYBR17 gene knockout plants were obtained, and the number of tillers per plant and the yield per plant of rice per plant were significantly reduced compared with Zhonghua 11 (ZH11).

[0012] The above studies show that overexpression of the OsMYBR17 gene in rice plants can increase rice yield, specifically by simultaneously increasing the number of tillers per rice plant, biomass, number of panicle branch differentiation, and number of rice grains.

[0013] In this scheme, the inventor has discovered a new function of the gene, and used this function to breed rice, and obtained unexpected technical effects. For the OsMYBR17 gene, the OsMYBR17 gene belongs to the MYB family, is a MYB transcriptional regulatory factor, and encodes a MYB domain. As a family of transcription factors with a large number in plants, most members of the MYB family regulate the stress response of plants. Although it has been reported that some MYB family members participate in the regulation of tillering, such as the OsMYB110 gene report affects tillering while regulating rice plant height (CN111187789B a kind of rice MYB transcription factor and its recombinant expression vector application). However, the existing report OsMYB110 independently regulates tillering, and does not suggest its influence on the panicle development process. Although it has also been reported that some MYB family members participate in the regulation of panicle development, such as the SFL gene belonging to the MYB family regulates flower organs to affect panicle development, it may be a key gene controlling the panicle development signaling pathway. Through phenotypic observation, it was found that after editing the gene in rice, the plant will be short and not panicle. However, the SFL gene independently affects the panicle development process and has no effect on tillering (Hu Guang. Gene editing and intercellular movement analysis of MYB transcription factors that control rice panicle development. Yangtze University, 2020.). In addition, the regulation of panicle development by the SFL gene is achieved by regulating the floral organs, and does not achieve the regulation of panicle development by regulating panicle branch differentiation, etc. The mechanism of action is different from that of the OsMYBR17 gene in this technical solution.

[0014] Therefore, in the prior art, there is no report that MYB transcription factors can positively regulate tillering and panicle development at the same time. The reported MYB transcription factors, if related to rice tillering or panicle development, all independently regulate the two developmental processes. At the same time, there is no report in the prior art about the OsMYBR17 gene increasing rice yield. The inventors have found that the OsMYBR17 gene can not only increase rice yield, but also positively regulate rice tillering and panicle development at the same time, which shows that the inventors have discovered new properties and new functions of the MYB gene, and applied the newly discovered OsMYBR17 gene to the practical operation of rice breeding, thereby obtaining a new type of rice plant and increasing rice yield.

[0015] In summary, the beneficial effects of this solution are as follows:

[0016] Overexpression of the cloned OsMYBR17 gene significantly increased the number of tillers per rice plant, biomass and the number of panicle branch differentiation, indicating that the OsMYBR17 gene has a significant effect on improving rice plant type and increasing rice yield per plant. Therefore, improving the expression of the OsMYBR17 gene through genetic engineering technology can genetically improve rice plant type and yield.

[0017] The successful cloning of the OsMYBR17 gene confirms that MYB transcription factors not only play a role in plant adversity response and stress, but also play an important role in plant tillering, panicle development, and plant growth and development. It can enrich the understanding of plant MYB genes and greatly promote the genetic improvement of plant branching and yield.

[0018] Furthermore, the nucleotide sequence of the OsMYBR17 gene is shown in SEQ ID NO.2.

[0019] Furthermore, the OsMYBR17 gene is used to increase the number of tillers in rice.

[0020] Furthermore, the OsMYBR17 gene was used to promote rice panicle development.

[0021] Furthermore, promoting rice panicle development includes increasing the number of panicle branch differentiation, the panicle length of a single panicle branch, the single panicle weight, and the number of grains in a single panicle.

[0022] Furthermore, the OsMYBR17 gene is used to increase rice yield.

[0023] The above technical scheme can be used in rice breeding based on the function of the OsMYBR17 gene discovered by the inventor. The purpose of rice breeding is to obtain rice plants with high tillering number per plant, biomass, number of panicle branch differentiation, number of rice grains or single plant yield. The expression of the OsMYBR17 gene can be increased by overexpression technology to obtain rice plants with excellent properties such as high number of tillers per plant, high biomass, high number of panicle branch differentiation, high number of rice grains and high single plant yield.

[0024] Furthermore, the transcription level of the OsMYBR17 gene in rice is increased, or the expression level of the OsMYBR17 protein is increased.

[0025] By adopting the above technical scheme, in the rice plants overexpressing the OsMYBR17 gene, the expression level of the OsMYBR17 protein is increased, and the number of rice tillers, the number of panicle branch differentiation and the yield per plant are also increased.

[0026] Furthermore, the cDNA of the OsMYBR17 gene was cloned from wild-type rice, and then the cDNA of the OsMYBR17 gene was integrated into the pCAMBIA-1306 vector to obtain the overexpression vector OsMYBR17-p1306; the overexpression vector OsMYBR17-p1306 was introduced into the wild-type rice using the Agrobacterium-mediated genetic transformation method, and after screening and cultivation, the OsMYBR17 gene overexpression plants were obtained.

[0027] Furthermore, the nucleotide sequences of the primers used to clone the cDNA of the OsMYBR17 gene are shown in SEQ ID NO.3 and SEQ ID NO.4. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The real-time fluorescence quantitative PCR statistical bar graph of the overexpression plant of Example 1 of the present invention (A) and the gene knockout target design and knockout plant gene sequence comparison schematic diagram (B).

[0029] Figure 2 The phenotype diagram (A) and the statistical bar graph (B: the first tillering bud; C: the second tillering bud) of the hydroponic rice single seedling of Experimental Example 1 of the present invention are shown.

[0030] Figure 3 The phenotype diagram (A) and statistical bar graph (B: plant height; C: fresh weight) of the hydroponic rice single seedling in Experimental Example 1 of the present invention are shown.

[0031] Figure 4 This is the phenotype diagram of a single rice plant planted in the field according to Experimental Example 2 of the present invention.

[0032] Figure 5 This is the branching phenotype of a single panicle of rice planted in the field according to Experimental Example 2 of the present invention.

[0033] Figure 6 This is a rice yield phenotype diagram of a single rice plant planted in the field according to Experimental Example 2 of the present invention.

[0034] Figure 7 This is a statistical bar chart of the yield of a single rice plant in field planting according to Experimental Example 2 of the present invention.

[0035] Figure 8 This is a statistical bar chart of the number of first branch differentiation of single panicle branches of rice planted in the field according to Experimental Example 2 of the present invention.

[0036] Fig. 9 This is a statistical bar chart of the number of second branch differentiation of single panicle branches of rice planted in the field according to Experimental Example 2 of the present invention.

[0037] Fig.10 This is a statistical bar chart of the ear length of a single ear of rice planted in the field according to Experimental Example 2 of the present invention.

[0038] Fig.11 This is a statistical bar chart of ear weight of a single ear of rice planted in the field according to Experimental Example 2 of the present invention.

[0039] Fig.12 This is a statistical bar chart of the number of grains per ear of rice planted in the field according to Experimental Example 2 of the present invention. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with the examples, but the embodiments of the present invention are not limited thereto. If not otherwise specified, the technical means used in the following examples are conventional means known to those skilled in the art; the experimental methods used are all conventional methods, and can be completed according to the described recombinant technology (see Molecular Cloning, Laboratory Manual, 2nd Edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York; MaXetal, Arobust CRISPR / Cas9 system for convenient, high-efficiency multiplex genome editing in monocot and dicotplants.MolPlant.2015,8(8):1274-1284.); the materials, reagents, etc. used can be obtained from commercial sources.

[0041] Example 1: Construction of OsMYBR17 gene overexpression plants

[0042] RNA was extracted from rice Zhonghua 11 (ZH11) and reverse transcribed into cDNA. The cDNA of OsMYBR17 gene was amplified by PCR using primer pair F1 and R1 (the protein sequence of OsMYBR17 gene is shown in SEQ ID NO.1, and the gene sequence is shown in SEQ ID NO.2).

[0043] SEQ ID NO.1:

[0044] Met Asp Leu Tyr Gly Ala Ala Ala Gly Gly Gly Pro Val Ala Arg Arg ProTrp Ser Lys ValGlu Asp Lys Val Phe Glu Ser Ala Leu Val Leu Cys Pro Glu AspVal Pro Asp Arg Trp Ala LeuVal Ala Ala Gln Leu Pro Gly Arg Thr Pro Gln GluAla Leu Glu His Tyr Gln Val Leu Val AlaAsp Ile Asp Leu Ile Met Arg Gly AlaVal Asp Ala Pro Gly Ser Trp Asp Asp Asn Asp Gly AsnAsp Arg Arg Gly Gly GlyGly Lys Pro Arg Gly Glu Glu Arg Arg Arg Gly Val Pro Trp Ser GluAsp Glu HisArg Leu Phe Leu Glu Gly Leu Asp Arg Tyr Gly Arg Gly Asp Trp Arg Asn IleSerArg Phe Ser Val Arg Thr Arg Thr Pro Thr Gln Val Ala Ser His Ala Gln LysTyr Phe Ile ArgGln Ala Asn Ala Gly Ala Arg Asp Ser Lys Arg Lys Ser Ile HisAsp Ile Thr Thr Pro。

[0045] SEQ ID NO.2(O.sativa v7.0|LOC_Os01g64360.1 CDS):

[0046] .

[0047] Primer pairs F1 and R1, respectively:

[0048] F1: 5'-atgaattcatggatttgtacggcgcggcggcg-3' (SEQ ID NO. 3, containing restriction enzyme cleavage site EcoRI);

[0049] R1: 5'-ataagctttcaaggggtggtgatgtcatggat-3' (SEQ ID NO. 4, containing enzyme cleavage site HindIII).

[0050] Then, the cDNA of OsMYBR17 gene was connected into pCAMBIA-1306 vector (pCAMBIA-1306 vector purchased from Cambia) through two restriction sites EcoRI and HindIII to construct the overexpression vector OsMYBR17-p1306 of OsMYBR17 gene. The overexpression vector was introduced into normal rice variety Zhonghua 11 by conventional Agrobacterium EHA105-mediated genetic transformation method in the prior art.

[0051] All the obtained T1 generation transgenic seedlings were cultured with normal nutrient solution with hygromycin for one week. If the seedlings can grow normally, it means that the transgenic plants are positive plants. All transgenic positive plants were transplanted into a basket with soil, watered regularly, fertilized, and planted in the field when the seedlings grew to about 15 cm. After the seedlings grew up, the transgenic rice plants were harvested and planted until the homozygous transgenic plants were identified in the T2 generation, and the OsMYBR17 gene overexpression plants were obtained. In this embodiment, three gene overexpression plants were prepared, namely OsMYBR17-OE1, OsMYBR17-OE4 and OsMYBR17-OE5.

[0052] The leaves of OsMYBR17 overexpressing plants were taken, RNA was extracted and reverse transcribed into cDNA, and the expression level of OsMYBR17 gene in overexpressing plants was detected by real-time fluorescence quantitative PCR. The results showed that ( Figure 1 A) The expression level of OsMYBR17 gene in the overexpression plant is higher than that in the control plant ZH11 (the expression level of wild-type ZH11 in the figure is defined as "1"). The experiment shows that the transgenic plant was successful, the gene was successfully overexpressed, and the overexpression plant was successfully constructed. Figure 1 In A, the test samples included the wild-type Zhonghua 11 (ZH11) control, and three strains of OsMYBR17 gene overexpression plants, OE1, OE4, and OE5; the statistical results are expressed as mean±SD, n=3. SPSS software was used for variance analysis (ANOVA), and Duncan test was used for significant difference analysis. The data are marked with lowercase letters above, and different lowercase letters indicate significant differences, p<0.05.

[0053] The sequences of the primer pairs F2 and R2 used in real-time fluorescence quantitative PCR are:

[0054] F2: 5'-ggaggacaaggtgttcgagagc-3' (SEQ ID NO.5);

[0055] R2: 5'-ggatgaagtacttctgcgcgtg-3' (SEQ ID NO. 6).

[0056] Example 2: Construction of OsMYBR17 gene mutant plants (gene knockout)

[0057] The OsMYBR17 gene knockout vector OsMYBR17-C was constructed using primer pair F5 and R5, where F5 and R5 are:

[0058] F5: 5'-tcactcggcatggatttgtagttttagagctagaaatagcaagtta-3' (SEQ ID NO. 7);

[0059] R5: 5'-gtcgttatcgtcccaggacccgccacggatcatctgcacaactc-3' (SEQ ID NO. 8).

[0060] The gene knockout was performed using the CRISPR / Cas9 system. The method is described in the prior art document: MaX et al., Arobust CRISPR / Cas9 system for convenient, high-efficiency multiplex genome editing in monocot and dicot plants. Mol Plant. 2015, 8(8): 1274-1284. The gene knockout expression vector was introduced into the normal rice variety Zhonghua 11 (ZH11) using the genetic transformation method mediated by Agrobacterium EHA105. The mutant plants were sequenced at the T0 generation, and it was determined that the gene had been knocked out in 3 strains ( Figure 1 B) and continued to independently propagate to the T1 generation, thus obtaining independent mutant plant lines of the OsMYBR17 gene (all homozygous mutants), namely: OsMYBR17-C5 (29 bp deletion), OsMYBR17-C7 (67 bp deletion) and OsMYBR17-C9 (53 bp deletion).

[0061] Experimental Example 1: Hydroponic Test

[0062] The seeds of the overexpression plant (Example 1), Zhonghua 11 (ZH11) and the gene knockout plant (Example 2) were soaked in distilled water on a culture dish for 3 days and cultured for 7 days, and then transferred to rice nutrient solution culture. The nutrient solution formula was prepared according to the conventional International Rice Institute formula in the prior art and the reference method (Yoshida S, Fomo DA, Cock JH, etc. Routine procedure for growing rice plants in culture solution. In: Laboratory manual for physio-logical studies of rice [J], International Rice Research Institute, 61-66.). The plants were cultured for 40 days, and the rice phenotype was observed. The number and biomass (i.e., fresh weight of seedlings) of rice tiller buds were counted, and the rice tiller buds were photographed under a fluorescent stereo microscope. The results of the tiller bud photography are as follows: Figure 2 As shown in A, it can be seen from the figure that the tiller number and tiller bud length of the OsMYBR17 gene overexpression plant increased compared with the control Zhonghua 11 plant, and the difference was significant. The tiller number and tiller bud length of the OsMYBR17 gene knockout mutant plant decreased compared with the control Zhonghua 11 plant, and the difference was significant.

[0063] The length of tillering buds of the hydroponic plants of Example 1 and Example 2 was statistically analyzed. The statistical results are shown in Figure 2 B and C. The statistical results of rice tiller buds showed that the tiller bud length of OsMYBR17 overexpression plants was significantly increased compared with the control Zhonghua 11 plants. The tiller number and tiller bud length of OsMYBR17 knockout mutant plants were significantly reduced compared with the control Zhonghua 11 plants.

[0064] The biomass statistics of the hydroponic plants in Example 1 and Example 2 were performed, and the biomass statistics results showed that ( Figure 3 ), the biomass of OsMYBR17 overexpression plants was increased compared with the control Zhonghua 11 plants, and the difference was significant. The biomass of OsMYBR17 knockout mutant plants was reduced compared with the control Zhonghua 11 plants, and the difference was significant.

[0065] Among them, Figure 2 and Figure 3 Statistical results are expressed as mean±SD, n=10; SPSS software was used for analysis of variance (ANOVA), and Duncan test was used for significant difference analysis. Lowercase letters are marked above the data, and different lowercase letters indicate significant differences, p<0.05.

[0066] Experimental Example 2: Field Planting Experiment

[0067] Field planting experiments were conducted using overexpression plants (Example 1), Zhonghua 11 (ZH11) and knockout plants (Example 2). Three strains of OsMYBR17 overexpression plants, three strains of OsMYBR17 knockout plants and one control Zhonghua 11 (ZH11) were randomly selected from the field and placed in a small bucket for photography. It was found that the overexpression plants had more tillers and the knockout plants had less tillers ( Figure 4 ). One ear was randomly selected from each of the three strains of overexpression plants, the three strains of gene knockout plants, and the control flower 11, and all the fully differentiated ear branches were unfolded and photographed. It was found that the number of ear branch differentiation in the overexpression plants was increased compared with the number of ear branch differentiation in the control flower 11, and the number of ear branch differentiation in the gene knockout plants was decreased compared with the number of ear branch differentiation in the control flower 11 ( Figure 5). A plant was randomly selected from the three strains of overexpression plants, the three strains of gene knockout plants, and the control flower 11, and all the shelled and filled rice seeds were arranged in a circle. It was found that the circle of the seeds of the overexpression plants was larger than that of the control flower 11, and the circle of the seeds of the gene knockout plants was smaller than that of the control flower 11 ( Figure 6 The yield per plant of the overexpression plants, gene knockout plants and control group was counted. The statistics showed that the yield per plant of the overexpression plants was significantly higher than that of the control group, but the yield per plant of the gene knockout plants was significantly lower ( Figure 7 ). The number of first branch differentiation of panicle branches in overexpression plants, gene knockout plants and control group plants was counted. The statistics showed that the number of first branch differentiation in overexpression plants was significantly increased compared with the control group, but that in gene knockout plants was significantly reduced ( Figure 8 ). The number of secondary branch differentiation of panicle branches in overexpression plants, gene knockout plants and control plants was counted. The statistics showed that the number of secondary branch differentiation in overexpression plants was significantly increased compared with the control group, but that in gene knockout plants was significantly reduced ( Fig. 9 ). The spike lengths of the overexpression plants, knockout plants, and control plants were statistically analyzed. The results showed that the spike lengths of the overexpression plants were significantly longer than those of the control group, but the knockout plants were significantly shorter ( Fig.10 ). The single ear weight of the overexpression plants, gene knockout plants and control group plants was statistically analyzed. The statistics showed that the single ear weight of the overexpression plants was significantly increased compared with the control group, but the single ear weight of the gene knockout plants was significantly reduced ( Fig.11 ). The number of grains per ear in the overexpression plants, gene knockout plants and control group plants was counted. The statistics showed that the number of grains per ear in the overexpression plants was significantly increased compared with the control group, but the number of grains per ear in the gene knockout plants was significantly decreased ( Fig.12 ).

[0068] exist Figure 7-12 Statistical results are expressed as mean±SD, n=10; SPSS software was used for analysis of variance (ANOVA), and Duncan test was used for significant difference analysis. Lowercase letters are marked above the data, and different lowercase letters indicate significant differences, p<0.05.

[0069] The above results show that after the OsMYBR17 gene is expressed, normal rice not only has more tillers, but also more panicle branch differentiations (first branch differentiations, second branch differentiations), longer panicle lengths, more panicle weights, and more panicle grains. By knocking out the OsMYBR17 gene, the number of rice tillers and panicle branch differentiations are reduced at the same time, which in turn reduces the number of seeds per plant, thereby reducing the yield per plant and seriously affecting the yield per unit area of ​​rice.

[0070] Comparative Example 1

[0071] The MYB (v-myb avain myeloblastosis viral oncogene homolog) transcription factor family is one of the transcriptional regulatory factor families with more members in plants, and is involved in a variety of physiological and biochemical processes in plants. Most of the MYB transcription factors reported so far bind to downstream genes to start gene expression in order to increase the expression of downstream genes, and a small number of members inhibit gene expression. The MYB gene encoding the MYB transcription factor is so called because it has a highly conserved MYB domain (DNA binding domain). MYB genes are divided into four subgroups according to the number of conserved domains they have: 1R, R2R3, 3R and 4R. The only similarity between MYB genes is that they all contain MYB domains, and the function of MYB domains is to bind to the DNA sequence of a gene (regulate the expression of the gene, etc.); there is no similarity between MYB genes in other domains or sequences of MYB genes. Therefore, although MYB genes have the commonality of the above-mentioned MYB domains, there are very large differences in gene sequences, protein structures, etc. between different MYB genes. Different MYB genes are involved in the regulation of cell proliferation, cell differentiation, hormone signaling, root structure, high temperature tolerance, various abiotic stress responses, growth and development processes, etc. Even if the genes belong to the same MYB gene, they may have very different functions. Therefore, it is difficult to predict the function of a gene simply by whether the gene belongs to the MYB gene (MYB transcription factor family). Table 1 shows some rice MYB genes and their functions that have been reported in the prior art. It can be seen that the diversity of MYB gene functions is very high, and gene functions cannot be inferred from one to another.

[0072] Table 1: Rice MYB genes and their functions reported in the prior art (cited from the literature "Jin Feng et al., Research Progress of Rice MYB Transcription Factors, Journal of Plant Genetic Resources, 2022; DOI: 10.13430 / j.cnki.jpgr.20221220001")

[0073]

[0074] Only very few documents in the prior art report that MYB transcription factors are involved in rice tillering regulation or panicle development regulation. However, the reported MYB transcription factors cannot achieve simultaneous positive regulation of the above two events, and the MYB transcription factors involved in rice tillering regulation or panicle development regulation reported in the prior art have very low sequence similarity compared to the OsMYBR17 gene or protein of this scheme. Gene function is largely determined by its material basis sequence composition. When the sequence similarity is very low, it is difficult to infer whether the gene has similar function. The following is a specific description taking the OsMYB110 gene and the SFL gene as examples.

[0075] Chinese patent CN111187789B reports an application of a rice MYB transcription factor and a recombinant expression vector thereof. The sequence number of the rice MYB transcription factor gene OsMYB110 is LOC_Os10g0478300, which can be used to regulate rice plant height, tillering, flowering period and rice quality. The invention provides the biological functions of the OsMYB110 transcription factor gene and its encoded protein for the first time through systematic research. The OsMYB110 overexpression material obtained by the present invention through transgenic means significantly increases the expression level of the gene in rice, resulting in a decrease in plant height, an increase in tillering, an early flowering period and improved rice quality in transgenic rice compared with the wild-type control. The protein sequence of the gene with the patent serial number LOC_Os10g0478300 (SEQID NO.9, Rice Annotation Project Database; https: / / rapdb.dna.affrc.go.jp / ) was compared with the gene protein sequence of this solution (SEQ ID NO.1) (NCBI Blast). Only about twenty amino acid residues can form a match, and the number of amino acid residues of the two proteins is 276aa and 173aa, respectively. This shows that the sequence similarity of the two proteins is very low. Researchers in this field will not speculate that another gene with almost no sequence similarity may have the function of promoting rice tillering based on the OsMYB110 gene. In addition, the gene of this solution not only promotes rice tillering, but also has a very obvious promoting effect on promoting rice panicle development. It can be seen that the gene function of this solution is different from that of the prior art.

[0076] It has been reported in the literature that the SFL gene has the function of regulating the development of rice panicles, and the SFL gene belongs to the MYB gene (Hu Guang. Gene editing and intercellular movement analysis of MYB transcription factors that control rice panicle development. Yangtze University, 2020.). In the literature, the sequence number of the SFL gene is LOC_Os07g43580. After consulting the database, its sequence is shown as SEQ ID NO.10. Compared with the gene protein sequence (SEQ ID NO.1) of this scheme (NCBI Blast), only a few amino acid residues can form a match, and the number of amino acid residues of the two proteins is 341aa and 173aa, respectively. Researchers in this field will not speculate that another gene with almost no sequence similarity may have the function of promoting rice panicle development based on the SFL gene. What's more, the regulation of panicle development by the SFL gene is achieved by regulating the floral organs, and it is not achieved by regulating panicle branch differentiation, etc., and the mechanism of action is different from the OsMYBR17 gene of this technical scheme. In addition, the genes of this solution not only promote the development of rice panicles, but also have a very obvious promoting effect on promoting rice tillering. It can be seen that the gene function of this solution is different from that of the existing technology.

[0077] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. Application of OsMYBR17 gene in rice planting, characterized in that: The protein encoded by the OsMYBR17 gene is a protein whose amino acid sequence is shown in SEQ ID NO.1; The transcription level of OsMYBR17 gene in rice is increased, or the expression level of OsMYBR17 protein is increased, so as to simultaneously increase the number of rice tillers and promote the development of rice panicles; promoting the development of rice panicles includes increasing the number of panicle branch differentiation, the panicle length of a single panicle branch, the single panicle weight, and the number of panicle grains per panicle; The OsMYBR17 gene was used according to the following method: the cDNA of the OsMYBR17 gene was cloned from wild-type rice, and then the cDNA of the OsMYBR17 gene was integrated into the pCAMBIA-1306 vector to obtain the overexpression vector OsMYBR17-p1306; the overexpression vector OsMYBR17-p1306 was introduced into the wild-type rice using the Agrobacterium-mediated genetic transformation method, and after screening and cultivation, the OsMYBR17 gene overexpression plants were obtained.

2. The use of the OsMYBR17 gene in rice planting according to claim 1, characterized in that: Its nucleotide sequence is shown in SEQ ID NO.

2.

3. The use of the OsMYBR17 gene in rice planting according to claim 1 or 2, characterized in that: It is used to increase rice production.

4. A rice planting method for simultaneously increasing the number of rice tillers and promoting the development of rice panicles, characterized in that: Overexpressing the OsMYBR17 gene in rice plants; the nucleotide sequence of the OsMYBR17 gene is shown in SEQ ID NO.2; Promoting rice panicle development includes increasing the number of panicle branch differentiation, panicle length of single panicle branch, single panicle weight, and the number of grains per panicle; The cDNA of OsMYBR17 gene was cloned from wild-type rice, and then the cDNA of OsMYBR17 gene was integrated into pCAMBIA-1306 vector to obtain overexpression vector OsMYBR17-p1306; Agrobacterium-mediated genetic transformation method was used to introduce overexpression vector OsMYBR17-p1306 into wild-type rice, and after screening and cultivation, OsMYBR17 gene overexpression plants were obtained.

5. A rice planting method for simultaneously increasing the number of rice tillers and promoting the development of rice panicles according to claim 4, characterized in that: The nucleotide sequences of the primers used to clone the cDNA of the OsMYBR17 gene are shown in SEQ ID NO.3 and SEQ ID NO.

4.

6. A method for constructing a rice plant with enhanced rice panicle development, characterized in that: Overexpressing the OsMYBR17 gene in rice plants; the nucleotide sequence of the OsMYBR17 gene is shown in SEQ ID NO.2; Promoting rice panicle enhancement includes increasing the number of panicle branch differentiation, panicle length of single panicle branch, single panicle weight, and the number of grains per panicle; The cDNA of OsMYBR17 gene was cloned from wild-type rice, and then the cDNA of OsMYBR17 gene was integrated into pCAMBIA-1306 vector to obtain overexpression vector OsMYBR17-p1306; Agrobacterium-mediated genetic transformation method was used to introduce overexpression vector OsMYBR17-p1306 into wild-type rice, and after screening and cultivation, OsMYBR17 gene overexpression plants were obtained.

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