Application of transcription factor B3-337 in improvement of tomato fruit quality

Abstract

The invention discloses an application of a tomato B3-337 transcription factor in improvement of tomato quality, a gene for coding a B3-337 transcription factor protein is named as a B3-337 gene, and the nucleotide sequence is shown as SEQ ID NO.1. The invention also discloses an application of the tomato B3-337 transcription factor in improvement of tomato quality. According to the application, a carrier pFM3100GFP-B3-337 is constructed, so that the B3-337 is proved to be positioned in a cell nucleus. A transcriptional activity detection result proves that B3-337 has transcriptional activation activity. RT-qPCR (real-time quantitative polymerase chain reaction) and GUS (glucuronidase) dyeing show that the transcription factor is expressed in pericarp, seed, placenta and center pillar of each fruit ripening stage. According to the invention, a B3-337 gene overexpression plant is obtained by constructing a B3-337 overexpression vector, and compared with a wild type, the tomato fruit overexpressed with the B3-337 gene has the advantages that the content of soluble solids brix is increased, the fruit becomes larger, and the weight becomes heavier. It is shown that the B3-337 transcription factor plays an important regulation role in positive regulation of tomato fruit quality. The invention lays a good gene genetic resource foundation for the cultivation of new varieties of high-quality tomatoes.

Description

Technical Field

[0001] The invention belongs to the field of biotechnology, and particularly relates to a protein B3-337 for regulating tomato fruit quality and an application thereof. Background Art

[0002] Tomato (Solanum lycopersicum) is one of the most important economic vegetable crops in the world and a classic model plant for studying fleshy fruits and quality formation. my country's tomato production has reached the first place in the world, but in the past people paid too much attention to tomato production and ignored quality. In recent years, with people's high requirements for the quality of agricultural products, consumers prefer high-quality tomatoes. Therefore, improving the quality of tomato fruit is crucial for improving important horticultural traits of fruits and meeting the high requirements of consumers. Among them, the regulatory role of transcription factors plays an important role in the formation of tomato fruit quality. In order to improve the quality of tomato fruit to meet market demand, this study used molecular biological methods combined with other biological techniques to find excellent transcription factors that regulate tomato fruit quality, and cultivated excellent varieties through bioengineering methods.

[0003] The soluble solid content can reflect the maturity of tomato fruit and is closely related to the flavor quality and nutritional value of the fruit. It is an important indicator for measuring the quality of tomato fruit. It includes water-soluble compounds such as sugars (monosaccharides and disaccharides), organic acids, vitamins and minerals. The increase in soluble solid content accompanies the ripening of the fruit, and can provide consumers with higher nutritional value and a wider consumer market choice, promoting the marketization of molecular breeding value. Previous studies have shown that transcription factors play an important role in regulating the quality and size of tomato fruit. For example, overexpression of SIBES1.8 leads to increased soluble sugar and organic acid content in the fruit (Su D, Wen L, Xiang W, et al. Tomato transcriptional repressor S1BES1.8 influences shoot apical meristem development by inhibiting the DNA binding ability of SlWUS. The Plant Journal, 2022(2): 110. DOI: 10.1111 / tpj.15683.); overexpression of the SlCDF4 gene affects cell division and expansion, thereby affecting fruit size. (Renau-Morata B, Carrillo L, Cebolla-Comejo J, et al. The targeted overexpression of SlCDF4 in the fruit enhances tomato size and yield involving gibberellin signalling. Scientific Reports, 2020, 10(1). DOI: 10.1038 / s41598-020-67537-x.). The fructose and glucose contents in the SlHY5 knockout strain were significantly higher than those in the wild type, indicating that SlHY5 can regulate sugar accumulation. (Jia HM, Xu YP, Deng YW, et al. Key transcription factors regulate fruitripening and metabolite accumulation in tomato, P1ant Physiology, 2024, 195(3). DOI: https: / / doi.org / 10.1093 / plphys / kiae195). These studies show that biobreeding technology has great potential and application prospects in improving tomato quality.However, there are no reports on the role of tomato transcription factors in regulating the soluble solids content of tomato fruit without affecting the appearance quality (size and weight) of the fruit. Summary of the invention

[0004] The purpose of the present invention is to provide a transcription factor B3-337 for regulating tomato fruit quality and the application of the transcription factor B3-337 in improving tomato fruit quality.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows:

[0006] The present invention finds a tomato B3-337 gene, the gene sequence number (Sequence ID) of the gene in NCBI is XM_004230585.5, the nucleotide sequence is shown in SEQ ID NO.1, the messenger RNA (mRNA) sequence length of the GhRV8 gene is 1011 bp, and the coding sequence length of the B3-337 gene is 1011 bp.

[0007] Through cloning and preliminary research on the tomato B3-337 gene, the inventors found that B3-337 has a certain effect on the quality of tomato fruit, and the tomato B3-337 gene is positively correlated with the quality of tomato fruit; that is, after the gene is overexpressed, the quality of tomato fruit is improved. This can lay a certain genetic resource foundation for the cultivation of high-quality new tomato varieties.

[0008] The present invention also constructs a series of plant expression vectors, and the functions of the expression vectors containing the above-mentioned genes, transgenic plant lines and host cells containing the vectors in improving the quality of tomato fruits also fall within the protection scope of the present invention.

[0009] The main purpose of the present invention is to protect the above-mentioned transcription factor B3-337, the B3-337 gene encoding the transcription factor protein B3-337, and the application of biological materials containing the above-mentioned coding sequence in improving the quality of tomato fruits.

[0010] The improvement of tomato fruit quality is specifically manifested in that, compared with the wild type, the B3-337 gene overexpression strain has a higher soluble solid content, larger fruits, and heavier weight.

[0011] In order to improve the fruit quality, the present invention also protects a new breeding method for improving the tomato fruit quality, wherein the method is to obtain fruits with higher fruit quality than the target plant by regulating the expression of the B3-337 gene in the target plant.

[0012] The method for regulating the expression of the B3-337 gene in the target plant is to overexpress or superexpress the B3-337 gene.

[0013] The target plant of the present invention is the cultivated tomato AC (Ailsa Craig).

[0014] The target gene, also known as the target gene, is used in genetic engineering design and operation to carry out gene recombination, change the characteristics of the recipient cell, and obtain the expected expression product. It can be from the organism itself or from a different organism.

[0015] In addition, those skilled in the art can easily mutate the B3-337 gene of the present invention by using known methods, such as directed evolution and point mutation. Those artificially modified nucleotides with 75% or higher identity to the nucleotide sequence encoding the transcription factor protein B3-337 are derived from the nucleotide sequence of the present invention and are equivalent to the sequence of the present invention as long as they encode the same protein and have the same function. Primer pairs for amplifying the full length or fragments of the coding sequence encoding the protein B3-337 also fall within the scope of protection of the present invention.

[0016] In the above method for improving the quality of tomato fruit, the B3-337 gene in the plant genome is overexpressed to obtain a B3-337 gene overexpressing plant, and a homozygous B3-337 gene overexpressing plant is obtained from the offspring of the B3-337 gene overexpressing plant; the homozygous B3-337 gene overexpressing plant is a plant with higher fruit quality. The self-pollinated offspring can be the offspring of the first generation of self-pollination, the offspring of the second generation of self-pollination, the offspring of the third generation of self-pollination, etc., until a homozygous B3-337 gene overexpressing plant is obtained. The fruit of the self-pollinated offspring of the homozygous B3-337 gene overexpressing plant is a high-quality tomato fruit.

[0017] The above method for improving the quality of tomato fruit is also applicable to other recipient plants with homologous genes to tomatoes. There is no particular limitation on the recipient plants applicable to the present invention, including not only tomatoes but also other plants with high homology, as long as they are suitable for gene transformation operations, such as various crops, flower plants or forestry plants. The plants may be, for example (but not limited to): dicots, monocots, woody plants, Rosales, Rosaceae, Prunus, peach, Cruciferae, Arabidopsis, Arabidopsis, etc.

[0018] The "plant" mentioned in the present invention includes the whole plant, its parent and progeny plants and different parts of the plant, including seeds, fruits, stems, buds, leaves, roots, flowers, tissues and organs, and these different parts all have our target gene or nucleic acid. The "plant" mentioned here also includes plant cells, suspension cultures, callus, embryos, meristem areas and pollen, and similarly, each of the aforementioned objects contains the target gene / nucleic acid.

[0019] The present invention includes any plant cell, or any plant obtained or obtainable by the method therein, and all plant parts and propagules thereof. This patent also includes transfected cells, tissues, organs or whole plants obtained by any of the aforementioned methods. The only requirement is that the progeny exhibit the same genotypic or phenotypic characteristics, and the progeny obtained using the method of this patent have the same characteristics.

[0020] The present invention also extends to the harvestable parts of the plants as described above, but not limited to seeds, fruits, peels. It also further relates to other derivatives of the plants after harvest, such as organic acids, sugars, lycopene, tomatine, volatile substances, vitamins, minerals and proteins. The present invention also relates to foods or food additives obtained from the relevant plants.

[0021] Advantages of the present invention:

[0022] The present invention discovered a new transcription factor B3-337 that regulates plant fruit quality from tomatoes during the research process, and proved through experiments that, compared with the wild type, the B3-337 gene overexpression strain has a higher soluble solid content, larger fruits, and heavier weight, that is, the fruit quality of the B3-337 gene overexpression strain is significantly better than that of the wild type material, indicating that the B3-337 gene plays an important regulatory function in the formation of tomato fruit quality, which has important guiding significance for the genetic improvement of tomatoes. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the subcellular localization result of B3-337.

[0024] Figure 2 This is the result of the transcriptional activity detection of B3-337.

[0025] Figure 3 Figure A shows the tissue-specific expression results of B3-337 detected by fluorescence quantitative analysis; Figure B shows the tissue-specific expression results of B3-337 detected by GUS staining, Scale bar = 1 cm.

[0026] Figure 4 This is the identification result at RNA level of plants after overexpression of B3-337.

[0027] Figure 5The figure is an analysis of the soluble solids brix content, size and weight of the fruit of the B3-337 gene overexpression strain compared with the wild type; in the figure: Figure A is a fruit phenotype diagram, Scalebar = 1cm. Figure B shows the soluble solids content of the fruit of the B3-337 gene overexpression strain and the wild type plant after the same number of days of cultivation under the same conditions, Figure C shows the width of the fruit of the B3-337 gene overexpression strain and the wild type plant after the same number of days of cultivation under the same conditions, Figure D shows the length of the fruit of the B3-337 gene overexpression strain and the wild type plant after the same number of days of cultivation under the same conditions, and Figure E shows the weight of the fruit of the B3-337 gene overexpression strain and the wild type plant after the same number of days of cultivation under the same conditions. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with specific examples, and the advantages and features of the present invention will become clearer as the description proceeds. However, the specific experimental methods involved in the following examples are all conventional methods or implemented under the conditions recommended by the manufacturer's instructions unless otherwise specified.

[0029] Unless otherwise specified, the technical means used in the examples are conventional means known to those skilled in the art. The test methods in the following examples are conventional methods unless otherwise specified. Unless otherwise specified, the reagents and materials used can all be purchased from the market.

[0030] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only.

[0031] The terms "nucleic acid", "nucleic acid sequence", "nucleotide", "nucleic acid molecule" or "polynucleotide" as used herein are meant to include isolated DNA molecules (e.g., cDNA or genomic DNA), RNA molecules (e.g., messenger RNA), natural types, mutant types, synthetic DNA or RNA molecules, DNA or RNA molecules composed of nucleotide analogs, single-stranded or double-stranded structures. These nucleic acids or polynucleotides include gene coding sequences, antisense sequences and regulatory sequences of non-coding regions, but are not limited to these. These terms include a gene. "Gene" or "gene sequence" is widely used to refer to a functional DNA nucleic acid sequence. Therefore, a gene may include introns and exons in a genomic sequence, and / or include a coding sequence in a cDNA, and / or include a cDNA and its regulatory sequences. In specific embodiments, such as with respect to an isolated nucleic acid sequence, it is preferably assumed to be cDNA.

[0032] Unless otherwise specified, the first position of each nucleotide sequence in the sequence table is the 5' terminal nucleotide of the corresponding DNA / RNA, and the last position is the 3' terminal nucleotide of the corresponding DNA / RNA.

[0033] The inventors of the present invention discovered a new transcription factor for regulating plant fruit quality from tomatoes during the research process, named B3-337 transcription factor. The gene encoding B3-337 transcription factor was named B3-337 gene, the gene number in the NCBI database is LOC101244128, and the gene sequence ID is XM_004230585.5.

[0034] Example 1B Cloning of 3-337 gene

[0035] RNA was extracted from wild-type tomato fruit, and the cDNA obtained by reverse transcription was used as a template. The specific primers were designed by Primer 5.0 based on the gene sequence obtained from the NCBI database, and the coding sequence of the B3-337 gene (as shown in SEQ ID NO.1) was cloned by PCR reaction. The sequence of SEQ ID NO.1 is as follows:

[0036]

[0037]

[0038] Example 2 Subcellular localization of B3-337 protein

[0039] 1. Using the double-stranded DNA molecule shown in SEQ ID NO.1 in the sequence table as a template, PCR amplification was performed using a primer pair consisting of B3-337-GFPF and B3-337-GFPR, and the PCR amplification product was recovered.

[0040] B3-337-GFPF:

[0041]

[0042] B3-337-GFPR:

[0043]

[0044] 2. Double digest the pFM3100 vector with restriction endonucleases EcoRI and SalI to recover the vector backbone.

[0045] 3. The recovered product obtained in step 1 and the vector backbone obtained in step 2 were connected using a homologous recombination kit to obtain a recombinant plasmid pFM3100-B3-337. The plasmid was then transferred into Agrobacterium.

[0046] 5. Pick a single clone containing the target gene on the bacterial plate and place it in 5 mL of YEP medium containing Rif and Kana, shake overnight, then add it to 100 mL of YEP (Rif+Kana) medium, shake and culture at 28°C 200 rpm for about 8 hours, and detect the OD of the shaken bacterial solution. 600 When the value is 0.5-0.8, collect the bacterial solution at 4000rpm for 5 minutes and resuspend the bacteria with resuspension solution to OD 600 To 1, resuspend the bacterial solution and let it stand at room temperature for 2-3 hours.

[0047] 6. Take a 3-4 week old tobacco plant and use your thumb to press the syringe to inject the bacterial solution into the leaves from the lower epidermis of the tobacco leaves.

[0048] 7. After culturing tobacco in the dark for 2 days, the expression of GFP in tobacco epidermal cells was observed using a laser scanning confocal microscope (LSM510META, Zeiss). The objective magnification was 20 times, the excitation wavelength was 488nm, the bandpass was BP505-530nm, and the long pass was LP560nm.

[0049] The results of the cells under laser scanning confocal microscopy are shown in Figure 1 , showing that the B3-337-GFP signal completely overlaps with the cell nucleus and the nuclear dye DAPI signal, indicating that the B3-337 transcription factor is localized in the cell nucleus.

[0050] Example 3B Detection of transcriptional activity of 3-337

[0051] 1. Using the double-stranded DNA molecule shown in SEQ ID NO. 1 in the sequence listing as a template, PCR amplification was performed using a primer pair consisting of B3-337-GAL4BDF and B3-337-GAL4BDR, and the PCR amplification product was recovered.

[0052] B3-337-GAL4BDF:

[0053]

[0054] B3-337-GAL4BDR:

[0055]

[0056] 2. Double digest the GAL4BD vector with restriction endonucleases EcoRI and SalI to recover the vector backbone.

[0057] 3. The recovered product obtained in step 1 and the vector backbone obtained in step 2 were connected using a homologous recombination kit to obtain a recombinant plasmid GAL4BD-B3-337, and the plasmid was transferred into Agrobacterium.

[0058] 4. Extract Arabidopsis protoplasts, add reporter gene vector plasmid 35S-LUC and internal reference control plasmid pTRL in a ratio of 6:6:1 in a 2 mL round-bottom centrifuge tube to co-transform the protoplasts.

[0059] 5. Transcriptional activity detection: Dual-luciferase reporter assay aystem kit (Promega) was used for transcriptional activity detection, and the detection instrument was GloMax 20 / 20 luminescence detector (Promega). The transcriptional activation or inhibition activity of the target gene was determined by detecting LUC activity. The results showed that the relative luciferase activity ratio of GAL4BD-B3-337 was significantly higher than that of the control GAL4BD ( Figure 2 ), indicating that the GAL4BD-B3-337 transcription factor has transcriptional activation activity.

[0060] Example 4B Tissue-specific expression analysis of 3-337

[0061] 1. Fluorescence quantitative detection of B3-337 tissue-specific expression

[0062] Fruits at four different stages, namely, mature green stage (MG), breaker stage (BR), orange ripe stage (OR), and redripe stage (RR), were selected as materials. The peel, pith, placenta, and seeds were harvested and RNA was extracted. The cDNA of the above tissues was obtained by reverse transcription and diluted 10 times as a template. The expression of the B3-337 gene in each tissue at each stage was detected by qRT-PCR. The experimental results are shown in Figure 2. Figure 3 As shown in A: The relative expression level of the gene in the pericarp tissue during the MG period was set as the control, and the B3-337 gene was expressed in the pericarp, septum, placenta, seeds and gel (Locular tissue and seeds) of the four periods of tomato fruit. Specifically, the expression level of B3-337 was higher in various tissues during the color breaking period of the fruit.

[0063] 2. GUS staining to detect tissue-specific expression of B3-337

[0064] 1. Using the tomato genome as a template, clone the 2000bp sequence upstream of the start codon of B3-337, use the primer pair consisting of B3-337-proF and B3-337-proR for PCR amplification, and recover the PCR amplification product. Use the homologous recombination method to construct it into the pQB-V3 vector, and then use the Gateway method to construct it into the pGWB3 expression vector to complete the construction of the pB3-337::GUS expression vector.

[0065] B3-337-proF:

[0066]

[0067] B3-337-proR:

[0068]

[0069] 2. Genetically transform the constructed vector into tomato to obtain pB3-337::GUS transgenic tomato. Positive seedlings were identified by genomic DNA level, and then the tissue-specific expression of B3-337 was detected by GUS staining using transgenic lines containing GUS reporter gene.

[0070] 3. GUS staining analysis ( Figure 3 B) It was found that the B3-337 gene had strong GUS signals in the pericarp, septum, placenta, seeds and gel (locular tissue and seeds) of tomato fruit at four stages, which was consistent with the results of quantitative detection of tissue-specific expression of B3-337.

[0071] Example 5B Functional Identification of Gene 3-337

[0072] 1. Construction of B3-337 gene overexpression vector

[0073] 1. Amplification of target gene B3-337

[0074] pK2-35S-B3-337-F and pK2-35S-B3-337-R were synthesized respectively, and the B3-337 gene shown in SEQ ID NO.1 was amplified by PCR.

[0075] pK2-35S-B3-337-F:

[0076]

[0077] pK2-35S-B3-33 7-R:

[0078]

[0079] 2. Using the Gateway method, the pK2-35S-B3-337 recombinant vector was obtained and sequenced and identified.

[0080] 2. Obtaining B3-337 gene overexpression plants

[0081] 1. Take the B3-337 gene overexpression vector constructed in step 1 and introduce it into Agrobacterium GV3101 to obtain recombinant Agrobacterium.

[0082] 2. Sterilize the tomato seeds first, then sow them on 1 / 2MS. Place them in a light incubator and wait for germination.

[0083] 3. About 6-8 days after sowing, the seeds germinate and the cotyledons flatten. Cut the cotyledons and soak them in MS liquid medium for 1 hour. Then use sterilized filter paper to absorb the remaining medium on the cotyledons and place them on A1 solid medium (MS+1mg / LIAA+1.75mg / LZT) for pre-culture for 1 day.

[0084] 4. Inoculate the recombinant Agrobacterium obtained in step 1 into the infection solution and adjust the concentration to OD 600 =1.8-2.0. Resuspend the bacteria in 40 mL MS salt medium. Soak the pre-cultured cotyledons in the Agrobacterium suspension resuspended in MS salt medium for 15 min, absorb the excess bacterial solution with sterilized filter paper, and return to the original medium for co-culture for 2 days.

[0085] 5. After that, the cotyledons were transferred to A2 resistance medium (MS+1.0mg / L IAA+1.75mg / L ZT+75mg / L Kan+200mg / L Tim). After one week at 26℃ (16hr light) / 18℃ (8hr dark), they were transferred to A2 medium (7-10d) and then cultured in the dark for another two weeks.

[0086] 6. After that, the culture medium was changed every three weeks until callus was formed (after callus formation, it was transferred to A3 medium (MS + 1.0 mg / L IAA + 1.75 mg / L ZT + 50 mg / L Kan + 200 mg / L Tim) to induce germination and seedling formation.

[0087] 7. After the callus tissue differentiates into growth points, cut the growth points with a knife and transfer them to A4 medium (MS+50mg / L Kan+200mg / L Tim) for rooting screening.

[0088] 8. Identify and screen the positive transformed seedlings, and transplant the normally growing plants into nutrient soil for cultivation, which are the T1 generation plants.

[0089] 9. Screen B3-337 gene overexpression plants from T1 generation plants.

[0090] Specific steps: take plant leaves, extract genomic DNA by CTAB method, use primer pair consisting of primer F and primer R for PCR amplification, then recover PCR amplification products and sequence them, and screen B3-337 gene overexpression plants according to sequencing results.

[0091] Primer F: 5′-ttactattctagtcgacctgcaggc-3′;

[0092] Primer R: 5′-tctagcatggccgcgggata-3′.

[0093] 10. The B3-337 gene overexpressing plants obtained in step 9 are self-pollinated and seeds are harvested.

[0094] 11. Sow the seeds harvested in step 10 in a solid 1 / 2MS culture medium containing 50 mg / L kanamycin. After culturing for 10 days, transplant the normally growing plants into nutrient soil for cultivation, which are T2 generation plants.

[0095] 12. The T3 plants obtained from the self-pollination of a certain T2 plant are all homozygous B3-337 overexpressing plants. Plant the T3 overexpressing plants individually and collect leaves from the same part, extract RNA and perform quantitative detection to identify the RNA level. The quantitative primers are RTB3-337F and RTB3-337R. The identification results of B3-337 overexpressing plants at the RNA level are shown in Figure 4 The expression levels of OE1, OE4, OE6, OE7, and OE8 were all significantly increased.

[0096] Primer RTB3-337F:

[0097] Primer RTB3-337R:

[0098] The B3-337 gene overexpression strains OE1, OE4, and OE8 were finally selected for subsequent experiments.

[0099] 3. Identification of fruit phenotypes of tomato B3-337 gene overexpression lines

[0100] Phenotypic photographs were taken of the B3-337 gene overexpression lines OE1, OE4, OE8 and wild-type plants ( Figure 5 A) and identification, including soluble solids brix content of tomato fruit ( Figure 5 B) Fruit width ( Figure 5 C) Length( Figure 5 D) and weight ( Figure 5E). As shown in the figure, after the same number of days of cultivation under suitable conditions, the brix content, fruit size and weight of the B3-337-OE1, OE4 and OE8 overexpression lines were significantly higher than those of the wild-type fruit.

[0101] These results show that under suitable conditions, the fruit of the B3-337 gene overexpression line has a higher sugar content than the wild-type plant fruit in the same period of time, and the fruit size and weight are still larger. The above results show that the B3-337 transcription factor can positively regulate the fruit quality of tomatoes.

[0102] The embodiments described above are only preferred embodiments of the present invention and are only used to explain the present invention, not to limit the scope of implementation of the present invention. For those skilled in the art, other implementation methods can certainly be easily made by replacement or modification based on the technical contents disclosed in this specification. Therefore, all changes and improvements made on the principles of the present invention should be included in the scope of the patent application of the present invention.

Claims

1. Application of transcription factor B3-337 in improving tomato fruit quality, characterized in that: The nucleotide sequence encoding the B3-337 transcription factor gene is shown in SEQ ID NO.

1.

2. The use according to claim 1, characterized in that: The improvement of tomato fruit quality is specifically manifested in that, compared with the wild type, the B3-337 gene overexpression strain has a higher soluble solid content, larger fruits, and heavier weight.

3. The use according to claim 1, characterized in that: The transcription factor B3-337 also has transcriptional activation activity.

4. Use of a gene expression cassette, a recombinant vector, a recombinant microorganism, and a transgenic plant cell line containing the B3-337 gene of claim 1 in improving the quality of tomato fruit.

5. A breeding method for improving tomato fruit quality, characterized in that: By promoting the expression of the B3-337 gene in the target plant, a plant with higher fruit quality than the target plant is obtained, the nucleotide sequence of the B3-337 gene is shown in SEQ ID NO.1, and the target plant is tomato.

6. The method for improving tomato fruit quality according to claim 5, characterized in that: The method of promoting the expression of the B3-337 gene is overexpression or superexpression.

7. The method for improving tomato fruit quality according to claim 6, characterized in that: The B3-337 gene in the plant genome is overexpressed to obtain B3-337 gene overexpressing plants, and homozygous B3-337 gene overexpressing plants are obtained from the self-pollinated offspring of the B3-337 gene overexpressing plants; the homozygous B3-337 gene overexpressing plants are plants with higher fruit quality.

8. The method for improving tomato fruit quality according to claim 5, characterized in that: The improvement in tomato fruit quality is manifested in: increased soluble solids content, larger fruit size, and increased weight.

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