Application of Transcription Factor OsMYB51 in Increasing the Content of Volatile Metabolites in Rice

Abstract

The present invention relates to the technical field of plant genetic engineering, and discloses the application of the transcription factor OsMYB51 in increasing the content of volatile metabolites in rice. The amino acid sequence of the transcription factor OsMYB51 is shown in SEQ ID NO. 27. By overexpressing the OsMYB51 gene driven by a constitutive promoter in rice, the present invention significantly increases the content of volatile metabolites in rice, especially 2-acetyl-1-pyrroline. The advantages are that OsMYB51 promotes the synthesis of 2-acetyl-1-pyrroline in rice as a positive regulator, and can be applied to the improvement of the fragrance quality of rice.

Description

Technical Field

[0001] The present invention relates to the technical field of plant genetic engineering, and discloses the application of transcription factor OsMYB51 in increasing the content of volatile metabolites in rice. Background Art

[0002] Plants produce a large number of low molecular weight, lipophilic molecules with high vapor pressure, which are called volatile organic compounds (VOCs). These chemically and biologically diverse volatile metabolites act as aroma and flavor molecules through their interaction with human receptors, and also contribute to the interaction between plants and the environment through their interaction with insect receptors. In terms of food: Common vegetables and fruits in daily life are often judged for their maturity and freshness by their flavor and color. The volatile substances in fruits are mainly aldehydes, alcohols, esters, etc.; in addition to fruits, there are also seasonings, such as the flavor of pepper comes from pinene and phellandrene; in cosmetics: The main chemical components of rose essential oil are citronellol, geraniol, etc.; the main substances in daily skin toners are linalool, limonene, etc.; creams and lotions often contain methylionone Ⅰ and methylionone Ⅱ; in agriculture: Plant volatile substances can repel pests to protect plants. For example, the main volatile of celery, limonene, can be used to repel Bemisia tabaci. When tea plants are infected by pests and diseases, they will release farnesene and ocimene as signal molecules to activate the defense mechanisms of neighboring plants. Moreover, VOCs have gradually become a key indicator for consumers to measure the quality of crops and their processed products, and their particularity significantly affects the sensory quality of crops. As one of the most important food crops in the world, the fragrance of rice can effectively improve the quality and value of rice, and fragrant rice is deeply loved by consumers. Therefore, the research on fragrance genes and their application in genetic breeding have received extensive attention from rice geneticists and breeders.

[0003] Research shows that 2-acetyl-1-pyrroline (2-AP) is an important characteristic fragrance substance of fragrant rice. Due to its low odor threshold, 2-AP can significantly change the aroma of rice even at low concentrations, making it an important component contributing to the unique aroma of rice. So far, the molecular mechanism research on the aroma traits of rice has mainly focused on betaine aldehyde dehydrogenase 2 ( OsBADH2 ) OsBADH2Numerous mutations within the gene can transform non-fragrant rice varieties into fragrant ones. For example, there is a 2-base pair deletion in exon 1, a 7-base pair deletion in exon 2, an 803-base pair deletion between exon 4 and exon 5, an 8-base pair deletion and 3 single nucleotide polymorphisms (SNPs) in exon 7, a 7-base pair insertion in exon 8, 1 SNP each in exon 10 and exon 13, and a 1-base pair insertion / deletion / SNP in exon 14. All these mutations lead to a reduction or loss of OsBADH2 activity, thereby blocking the conversion of γ-aminobutyraldehyde (GABald) to γ-aminobutyric acid (GABA), thus promoting the accumulation of 2-AP.

[0004] The biosynthesis of VOCs depends on the content and availability of carbon, nitrogen, and sulfur, as well as the energy provided by primary metabolism. The biosynthesis of various different VOCs can only be separated from several major metabolic pathways. According to their biosynthetic sources, all VOCs are classified into four major categories, including terpenoids, phenylpropanoids / benzenoids, fatty acid derivatives, and amino acid derivatives. Terpenoids are derived from two common five-carbon precursors, namely isopentenyl diphosphate and its allylic isomer dimethylallyl diphosphate. Terpenoids are widely present in nature. For example, the highest contents in plants are terpenoids, coumarins, sterols, fatty acids, and sterol esters, etc. In plants, the synthesis of terpenoids involves two independent pathways, namely the mevalonic acid (MVA) pathway and the methylerythritol phosphate (MEP) pathway. The MVA pathway is mainly responsible for generating volatile sesquiterpenes (C15), while the MEP pathway is responsible for providing the precursor substances of volatile hemiterpenes (C5), monoterpenes (C10), and diterpenes (C20). Phenylpropanoids are various volatile organic compounds synthesized by plants from phenylalanine and tyrosine and can be divided into many categories, including phenylpropanols, coumarins, and lignins, etc. Phenylpropanoids / benzenoids are widely present in the plant kingdom and can resist the invasion of ultraviolet rays, herbivores, and pathogens. Fatty acid derivatives are from fatty acids. Fatty acids originally referred to even-carbon saturated straight-chain carboxylic acids existing in the form of triglycerides in common oils and fats, and later were extended to unsaturated fatty acids such as oleic acid, linoleic acid, and linolenic acid. Common ones in plants are 1-hexanal, nonanal, and methyl jasmonate, etc. Amino acid metabolism can be divided into branched-chain amino acid metabolism and aromatic amino acid metabolism according to different metabolic pathways of substrates. Leucine, isoleucine, and valine belong to branched-chain amino acids, while alanine and tyrosine belong to aromatic amino acids.

[0005] MYB transcription factors are the largest transcription factor family in plants and are widely present in eukaryotes. MYB affects taste and flavor by regulating aroma, astringency, and spiciness. MsMYB in Mentha spicata inhibits the activity of geranyl diphosphate synthase (GPPS) by binding to the promoter region of GPPS, thereby limiting the accumulation of monoterpenes. SlMYB75 in tomatoes can promote anthocyanin accumulation and enhance the production of volatile aroma in tomato fruits. Overexpression of SlMYB75 can activate the promoters of LOXC, AADC2, and TPS genes, thereby increasing the synthesis of various aromatic volatiles such as aldehydes, phenylpropanoid derivatives, and terpene volatiles. The HcMYB gene in Hedychium coronarium can directly bind to the promoters of underlying structure volatile synthesis genes (HcTPS1, HcTPS3, HcTPS10, and HcBSMT2), thereby participating in the regulatory mechanism of terpene and benzene biosynthesis in Hedychium coronarium. AtMYB21 and AtMYB24 in Arabidopsis thaliana are involved in the production of the sesquiterpene volatile (E)-β-caryophyllene. OfMYB1R114 and OfMYB1R70 in the floral organs of Osmanthus fragrans accelerate the formation of β-ionone, while OfMYB1R201 can reduce the synthesis of β-ionone. The volatile metabolites of rice are closely related to the fragrance quality, but the specific molecular mechanism of its regulation is not clear, and the regulatory network formed has always been one of the hot and difficult points of domestic and foreign research. Summary of the Invention

[0006] To solve the above problems, one of the objectives of the present invention is to provide the application of the transcription factor OsMYB51 in increasing the content of volatile metabolites in rice; another objective of the present invention is to provide a method for increasing the content of volatile metabolites in rice.

[0007] The technical solution adopted by the present invention to achieve the technical objectives is as follows:

[0008] Application of the transcription factor OsMYB51 in increasing the content of volatile metabolites in rice, wherein the amino acid sequence of the transcription factor OsMYB51 is as shown in SEQ ID NO.27.

[0009] Preferably, the nucleotide sequence of the transcription factor OsMYB51 is as shown in SEQ ID NO.26.

[0010] Preferably, the volatile metabolites include ethanol, vinyl acetate, 2,3-epoxybutane, isovaleraldehyde, 2-methylbutyraldehyde, 2-ethylfuran, 2-methyl-2-butenal, cis-2-methyl-2-butenal, pyrrolidine, 1,3-octadiene, 2-acetyl-1-pyrroline, heptanol, 1-octen-3-ol, 2-n-amylfuran, undecane, phenethyl alcohol, L-menthol, nonanol, trans-isopiperitenol, decanal, D-carvone, 2-undecenal, vanillin, hexadecanal, n-octadecane.

[0011] More preferably, the volatile metabolite is 2-acetyl-1-pyrroline.

[0012] Preferably, the transcription factor OsMYB51 promotes the synthesis of volatile metabolites by inhibiting the expression of genes in the 2-acetyl-1-pyrroline pathway in rice. OsBADH2

[0013] A method for increasing the content of volatile metabolites in rice, comprising: overexpressing the transcription factor OsMYB51 in rice, wherein the amino acid sequence of the transcription factor OsMYB51 is shown in SEQ ID NO. 27.

[0014] Preferably, the nucleotide sequence of the transcription factor OsMYB51 is shown in SEQ ID NO. 26.

[0015] Preferably, the method for overexpressing the transcription factor OsMYB51 in rice comprises: inserting the transcription factor OsMYB51 into a plant transformation plasmid containing the function of an overexpressed gene to obtain a plant overexpression vector of the transcription factor OsMYB51.

[0016] More preferably, the Gateway system is used for constructing the plant overexpression vector, and the required gene fragment is amplified using rice cDNA as a template, and the primer sequences are shown in SEQ ID NO. 5 and SEQ ID NO. 6.

[0017] More preferably, pH2GW7 is used as the starting vector of the plant overexpression vector.

[0018] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0019] The present invention discloses the application of the transcription factor OsMYB51 in increasing the content of volatile metabolites in rice. It is found that OsMYB51 promotes the synthesis of volatile metabolites by inhibiting the expression of genes in the 2-AP pathway in rice. Overexpressing this gene can significantly increase the content of volatile metabolites, indicating that the OsMYB51 transcription factor, as a positive regulatory factor, has important guiding significance and broad market prospects for improving the fragrance quality of rice. OsBADH2 BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 For the real-time fluorescence quantitative PCR detection of the rice leaves of the OsMYB51 overexpression and knockout mutant lines provided by the embodiments of the present invention OsBADH2 ​​Gene expression; OsMYB51-OE13, OsMYB51-OE23: Different transgenic rice lines with overexpression of OE-MYB51; Wild type: Wild type-ZH11 (A: Expression level of OsMYB51 gene in leaves of overexpression lines; B: Expression level of genes in leaves of overexpression and knockout mutant lines) OsBADH2 Gene expression).

[0021] Figure 2 Bar graph of the content of 2-AP in grains of OsMYB51 overexpression and mutant lines and line graph of the 2-AP standard curve determined by gas chromatography-mass spectrometry (GC-MS) provided in the examples of the present invention; OsMYB51-OE13, OsMYB51-OE23: Different transgenic rice lines with overexpression of OE-MYB51; osmyb51-14, osmyb51-15: Different transgenic rice lines with knockout mutation of CR-OsMYB51; Wild type: Wild type-ZH11 (A: Bar graph of the content of 2-acetyl-1-pyrroline in leaves of OsMYB51 overexpression and mutant lines; B: 2-acetyl-1-pyrroline standard curve).

[0022] Figure 3 Heat map of the content of volatile metabolites in grains of OsMYB51 overexpression lines determined by gas chromatography-mass spectrometry (GC-MS) provided in the examples of the present invention; OsMYB51-OE13-1, OsMYB51-OE13-2, OsMYB51-OE23-1, OsMYB51-OE23-2 represent different transgenic rice lines with overexpression of OE-OsMYB51; Wild type: Wild type-ZH11.

[0023] Figure 4 Provided in the examples of the present invention and verified by Dual-LUC (Dual-LUC) experiment that OsMYB51 binds to proOsBADH2 , thereby transcriptionally inhibiting the expression of OsBADH2; proOsBADH2 : Represents OsBADH2 Promoter OsBADH2 promoter (A: Vector schematic diagram; B: Dual-luciferase reporter gene activity of OsMYB51 on OsBADH2 Promoter).

[0024] Figure 5 Provided in the examples of the present invention and verified by yeast one-hybrid (Y1H) experiment that OsMYB51 binds to OsBADH2 Promoter; proOsBADH2: Represents OsBADH2 Promoter of OsBADH2 promoter (A: OsBADH2Motif analysis of the promoter region of the gene; B: Results of the yeast one-hybrid experiment of OsMYB51). Detailed implementation manners

[0025] In the following, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are denoted by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, their detailed descriptions will not be repeated.

[0026] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.

[0027] Example 1 Cloning of rice OsMYB51 gene and OsBADH2 promoter

[0028] 1. Extraction of total RNA from rice leaves

[0029] Take two fresh rice leaves with a length of 3 - 5 cm, quickly freeze them in liquid nitrogen, and grind them thoroughly into a powder state; add 1 ml of Trizol to the sample, and extract total RNA according to the method of the kit of TransGen Biotech. Use agarose gel electrophoresis to detect the quality of RNA, and use a NanoDrop 2000 spectrophotometer to detect the concentration of RNA.

[0030] 2. Cloning of rice genes

[0031] Using the extracted total RNA as a template, synthesize cDNA according to the one-step reverse transcription kit of TransGen Biotech; design PCR amplification primers according to the OsMYB51 gene sequence, and the primer sequences are shown in SEQ ID NO.1 and SEQ ID NO.2, as shown in Table 1.

[0032] Table 1 Cloning primers of rice OsMYB51

[0033]

[0034] Using the obtained cDNA as a template, PCR amplification was performed with the following program: pre-denaturation at 94°C for 2 min, denaturation at 94°C for 15 s, annealing at 60°C for 20 s, extension at 72°C for 1 min, repeating 35 cycles; final extension at 72°C for 5 min; storing at 25°C. PCR amplification was carried out using the OsMYB51 gene primers in Table 1. The product was recovered by gel cutting and sequenced to obtain the rice OsMYB51 sequence. The sequencing results showed that the full length of the obtained OsMYB51 gene was 930 bp, and its nucleotide sequence was as shown in SEQ ID NO.26; the obtained OsMYB51 gene encoded 310 amino acids, and its amino acid sequence was as shown in SEQ ID NO.27.

[0035] 3. Cloning of Rice Promoter

[0036] Referring to the CTAB extraction method for plant genomes, rice leaf DNA was extracted. According to proOsBADH2 the 1646 bp promoter sequence, PCR amplification primers were designed, and the primer sequences were as shown in SEQ ID NO.3 and SEQ ID NO.4, as shown in Table 2.

[0037] Table 2 Primers for Amplification of Rice proOsBADH2 of

[0038]

[0039] Using the obtained DNA as a template, PCR amplification was performed with the program: pre-denaturation at 94°C for 5 min, denaturation at 94°C for 15 s, annealing at 58°C for 20 s, extension at 72°C for 2 min, repeating 35 cycles; final extension at 72°C for 5 min; storing at 25°C. The PCR amplification product was recovered by gel cutting and sequenced to obtain the rice proOsBADH2 promoter sequence. The sequencing results showed that the obtained proOsBADH2 promoter sequence was 1646 bp in full length, and its sequence was as shown in SEQ ID NO.28.

[0040] Example 2 Construction of Plant Overexpression Vector

[0041] The construction of the plant overexpression vector uses the Gateway system. First, the required gene fragment is amplified using rice cDNA as a template, and the primer sequences are shown in SEQ ID NO.5 and SEQ ID NO.6, as shown in Table 3. The gel recovery product with the pDONR207 recombination adapter is obtained by PCR, and BP (LR) enzyme, pH2GW7 + pUbi (Smedley MA, Harwood WA. Gateway-compatible plant transformation vectors. Methods Mol Biol. 2015;1223:3-16.doi: 10.1007 / 978-1-4939-1695-5_1. PMID: 25300827.), and water are added to form a 2 μL system (see Table 4). Incubate in a 25 °C dry bath for 4 hours, transform DH5α, and after sequencing verification, the final vector pH2GW7_OE is obtained.

[0042] Table 3 Amplification primers for the rice overexpression vector

[0043]

[0044] Table 4 BP and LR reaction system table

[0045]

[0046] Example 3 Construction of the plant gene knockout vector

[0047] To construct the plant gene knockout vector, first, the gene editing target sites are designed using the online software CRISPR-P2.0 (http: / / crispr.hzau.edu.cn / CRISPR2), adopting a three-target site strategy. Using a 50 μL PCR amplification system, after digestion and ligation, transformation and colony PCR identification are carried out. The target site sequences of OsMYB51 are shown in SEQ ID NO.7-9 (see Table 5). Amplify the OsMYB51 editing sequence with SEQ ID NO.10 and SEQ ID NO.11, and then ligate it into pH-Ubi-cas9-7 (purchased from Addgene; catalog number: 106331) to obtain a plant transformation plasmid with the gene editing function of CRISPR / Cas9 for OsMYB51. The recombinant plasmid obtained is the knockout vector (this vector was constructed by Boyuan Biotechnology Co., Ltd.).

[0048] Table 5 Target site design information

[0049]

[0050] Table 6 Amplification primers

[0051]

[0052] Example 4 Stable Genetic Transformation of Rice Mediated by Agrobacterium tumefaciens

[0053] The plant overexpression vector and plant gene knockout vector of OsMYB51 were respectively introduced into Agrobacterium tumefaciens EHA105 for stable genetic transformation of rice. The specific steps are as follows:

[0054] Identification of positive Agrobacterium monoclonal: Take 1 μL of plasmid and add it to 50 μL of competent cells of Agrobacterium tumefaciens EHA105, mix well, add 1 mL of YEB liquid medium after electroporation, and incubate on a shaker at 30 °C and 180 rpm for 30 min. Inoculate on YEB solid medium and incubate in the dark at 28 °C for 48 h. After PCR identification, positive Agrobacterium monoclonal was obtained. The primer sequences for identification are shown in SEQ ID NO.5, SEQ ID NO.6, SEQ ID NO.10, SEQ ID NO.11, SEQ ID NO.12 and SEQ ID NO.13, as shown in Table 3, Table 6 and Table 7.

[0055] Rice genetic transformation: Select complete, plump and uniform-sized rice grains, disinfect with 70% alcohol for 2 min, wash with sterile water, disinfect with 30% sodium hypochlorite for 10 min, wash thoroughly with sterile water, and place on 1 / 2 MS medium for light culture for 7 - 8 d. Place the grown callus in the positive Agrobacterium bacterial liquid for 25 min, place it on sterile filter paper to dry in the shade, spread it on the co-culture medium, and co-culture in the dark at 25 °C for 2.5 - 3 days. Place the callus evenly on the screening medium, screen and culture in the dark at 25 °C for 2 - 3 weeks, transfer to the pre-differentiation medium, culture at room temperature with a 14 h / 10 h light / dark cycle for two weeks, and then transfer to the differentiation medium. Transfer the rice callus at the two-leaf or two-leaf and one-heart stage to the rooting medium. When the rice seedlings grow to about 10 cm, acclimatize them in water for 3 - 4 d and then transfer them to a flowerpot (the transgenic materials were created by Boyuan Biotechnology Co., Ltd.).

[0056] Identify T0 generation positive plants by PCR. The primer sequences for identification are shown in SEQ ID NO.12, SEQ ID NO.13, SEQ ID NO.14, SEQ ID NO.15, SEQ ID NO.16 and SEQ ID NO.17, as shown in Table 7, and continue to self-cross for one generation to obtain T1 generation positive plants for subsequent experiments and content analysis of related metabolites.

[0057] Table 7 Primer for PCR Identification of Positive Plants

[0058]

[0059] The expression levels of OsMYB51 and OsBADH2 genes in rice plants were determined by fluorescence quantitative PCR. The primer sequences for detection are shown in SEQ ID NO.18, SEQ ID NO.19, SEQ ID NO.20 and SEQ ID NO.21, as shown in Table 8.

[0060] Table 8 Primers for qPCR identification

[0061]

[0062] The detection results are as Figure 1 shown. In the rice plants of the OE-OsMYB51 overexpression lines, the expression level of the OsMYB51 gene increased significantly, while OsBADH2 the expression level of the OsBADH2 gene decreased significantly, indicating that OsMYB51 can inhibit the expression of the

[0063] Example 5 Determination of the content of volatile metabolites in rice leaves

[0064] Gas chromatography-mass spectrometry (GC-MS) can meet the requirements for accurate qualitative and quantitative determination of volatile metabolites. Its operation process is briefly as follows:

[0065] Sample preparation: The harvested mature grains were dehulled, and 300 μL of ddH 2 O was added to extract 1 g of the sample for GC-MS analysis.

[0066] The detection of volatile metabolites was performed using a gas chromatography system (7890AGC, Agilent Technologies) and a triple quadrupole mass spectrometry system (Agilent 7000D triple quadrupole mass detector). An HP-5 mass spectrometry capillary column (30 mm * 0.25 mm i.d., 0.25 mm film thickness; Agilent Technologies) was used to separate the volatile metabolites. The initial column temperature was 50 °C, held for 2 min, the temperature was increased at 5 °C / min to 200 °C, held for 2 min, then the temperature was increased at 20 °C / min to the final temperature of 250 °C, held for 2 min. The injection temperature was 230 °C, and the splitless mode was used. The He flow rate was 1.0 ml / min (99.999%). In the full scan mode, the scanning range was 35 - 500 m / z.

[0067] The results are as Figure 2 and 3 shown. The content of 2-AP in the overexpression lines of OsMYB51 was 7 - 8 μg•kg -1In the mutant lines of OsMYB51 and ZH11, the content of 2-AP was 0 μg•kg -1 .

[0068] Example 6 Verification of the interaction between OsMYB51 and proOsBADH2 and the action site

[0069] The OsMYB51 cloned in Example 1 was ligated into the vectors pGADT7 (product number: HG-VJC0483, Changsha Aibivi Biotechnology Co., Ltd.) and pB7WG2.0 (Dual-LUC) (product number: VT13019, Qingdao Corebio Biotechnology Co., Ltd.) to obtain the recombinant vectors OsMYB51-pGADT7 (yeast one-hybrid) and OsMYB51-pB7WG2.0 (Dual-LUC). The sequences of the upstream 1600bp proOsBADH2 were respectively constructed into the vectors pHIS2 (product number: HG-VJC0481, Changsha Aibivi Biotechnology Co., Ltd.) and pGEXT4-1 pGEXT4-1 (product number: HG-VYA0221, Changsha Aibivi Biotechnology Co., Ltd.) to obtain proOsBADH2-pHIS2 and proOsBADH2-pGEXT4-1. The construction of the vectors referred to the Gateway system in Example 2. The mature Y1H and Dual-LUC experimental systems were used to verify their interaction. Among them, the Y1H system uses the yeast competent system of Y187. If the pGADT7 and pHIS2 containing the target gene can grow normal plaques on the triple-deficient plate with 3-AT added, it can be determined that there is an interaction between DNA and protein. Dual-LUC was verified in tobacco leaves, and the binding of DNA and protein was judged by the fluorescence signal. The vector and primer sequences are shown in SEQ ID NO.22, SEQ ID NO.23, SEQ ID NO.24 and SEQ ID NO.25, as shown in Table 9.

[0070] Table 9 Vector and primer information

[0071]

[0072] The results are as Figure 4 and Figure 5 shown. OsMYB51 can bind to the promoter region of the OsBADH2 gene and significantly inhibit its expression.

[0073] It should be understood that the various forms of processes shown above can be used, reordering, adding or deleting steps. For example, the steps recorded in the disclosure of the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and no limitation is made herein.

[0074] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub - combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. Application of overexpression of transcription factor OsMYB51 in increasing the content of volatile metabolites in rice, characterized in that: The amino acid sequence of the transcription factor OsMYB51 is shown in SEQ ID NO.27, and the volatile metabolites are ethanol, vinyl acetate, 2,3-butylene oxide, isovaleraldehyde, 2-methylbutanal, 2-ethylfuran, 2-methyl-2-butenal, cis-2-methyl-2-butanal, tetrahydropyrrole, 1,3-octadiene, 2-acetyl-1-pyrroline, heptanol, 1-octen-3-ol, undecane, phenylethyl alcohol, L-menthol, nonanol, trans-isopiperenol, decanal, D-carvone, 2-undecenal, vanillin, hexadecanal and n-octadecane.

2. The use according to claim 1, characterized in that: The nucleotide sequence of the transcription factor OsMYB51 is shown as SEQ ID NO.

26.

3. The use according to claim 1 or 2, characterized in that: The volatile metabolite is 2-acetyl-1-pyrroline.

4. The use according to claim 1 or 2, characterized in that: The transcription factor OsMYB51 inhibits the rice 2-acetyl-1-pyrroline pathway OsBADH2 Gene expression promotes the synthesis of volatile metabolites.

5. A method for increasing the content of volatile metabolites in rice, characterized in that: include: The transcription factor OsMYB51 is overexpressed in rice, the amino acid sequence of the transcription factor OsMYB51 is shown in SEQ ID NO.27, and the volatile metabolites are ethanol, vinyl acetate, 2,3-butylene oxide, isovaleraldehyde, 2-methylbutanal, 2-ethylfuran, 2-methyl-2-butenal, cis-2-methyl-2-butanal, tetrahydropyrrole, 1,3-octadiene, 2-acetyl-1-pyrroline, heptanol, 1-octen-3-ol, undecane, phenylethyl alcohol, L-menthol, nonanol, trans-isopiperenol, decanal, D-carvone, 2-undecenal, vanillin, hexadecanal and n-octadecane.

6. The method according to claim 5, characterized in that The nucleotide sequence of the transcription factor OsMYB51 is shown as SEQ ID NO.

26.

7. The method according to claim 5 or 6, characterized in that: The method for overexpressing the transcription factor OsMYB51 in rice comprises: inserting the transcription factor OsMYB51 into a plant transformation plasmid containing an overexpression gene function to obtain a plant overexpression vector of the transcription factor OsMYB51.

8. The method according to claim 7, characterized in that The plant overexpression vector was constructed using the Gateway system.

9. The method according to claim 8, characterized in that pH2GW7 was used as the starting vector for plant overexpression vector.

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