Application of UBP1b in improving plant resistance to salt stress

Abstract

The present invention belongs to the field of genetic engineering technology, and specifically relates to the application of UBP1b in improving the ability of plants to resist salt stress. The nucleotide sequence of UBP1b is shown in SEQ ID NO.1. By constructing a UBP1b transient silencing expression vector and infecting tomato seedlings, it is found that before treatment, UBP1b silencing has no significant effect on the plant phenotype; after salt treatment, the UBP1b silenced plants show a more obvious salt-tolerant phenotype, with lower degrees of leaf wilting and yellowing. Compared with the control, the silenced plants have higher plant height, root length and fresh weight. Through CRISPR / Cas9 and tomato genetic transformation, a T2 generation UBP1b knockout transgenic homozygous strain is obtained. Under NaCl treatment, the knockout strain has a stronger ability to resist salt stress than the control plant. Therefore, knocking out and silencing UBP1b can improve the tolerance of tomatoes to salt stress.

Description

Technical Field

[0001] The invention relates to the technical field of genetic engineering, and in particular to application of UBP1b in improving the salt stress resistance of plants. Background Art

[0002] Soil salinization is one of the main environmental stresses currently faced by agricultural crop production. Saline soil (saline-alkali soil) often refers to soil rich in chlorides, sulfates and carbonates (bicarbonates) of sodium, potassium, calcium and magnesium. A small amount of mineral salts is essential for the normal growth and development of plants, while excessive mineral salts often turn into harmful substances that restrict the normal growth and development of plants, and in severe cases lead to plant death. High salt stress disrupts the balance of sodium and potassium ions in plants, leading to ion stress and secondary oxidative stress, affecting plant photosynthesis, respiration, and cell membrane structure, hindering the normal synthesis of proteins, and destroying a series of physiological metabolisms, thereby affecting plant growth and development in many ways, resulting in crop yield reduction or even death, and seriously affecting agricultural production.

[0003] Facing saline environment, plants regulate gene expression at multiple levels such as transcription, post-transcription, and translation, and then regulate metabolic synthesis to adapt to adverse environments. Among them, RNA binding proteins (RBPs) participate in the plant response to adversity by regulating gene expression at the post-transcriptional level. UBP1b (Oligouridylate Binding Protein 1b) is an RNA binding protein containing three RNA recognition domains (RRMs), but its molecular mechanism for regulating stress sensitivity, such as the characteristics of UBP1b targeting mRNAs, needs further study. Therefore, exploring the molecular regulatory mechanism of tomato salt stress and the regulation of tomato salt resistance by RNA binding proteins has important theoretical significance and production value. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides the use of UBP1b in improving the ability of plants to resist salt stress.

[0005] The application of UBP1b in improving the salt stress resistance of plants, the nucleotide sequence of UBP1b is shown in SEQ ID NO.1.

[0006] Preferably, a transgenic plant is obtained by knocking out the UBP1b to improve the plant's ability to resist salt stress.

[0007] Preferably, the method of knocking out the UBP1b includes base insertion, base deletion and insertion or formation of a stop codon.

[0008] Preferably, the method for preparing the transgenic plant comprises the following steps: designing a knockout target sequence according to the UBP1b gene sequence, constructing the knockout target sequence into the gene editing vector pCAMBIA1300-CAS9, and obtaining a UBP1b gene knockout plant by genetic transformation.

[0009] Preferably, the target sequence is 5'-TTATCATCCTGCTCTTCTTG-3'.

[0010] Preferably, the primer sequence for constructing the target sequence into the gene editing vector is as shown in SEQ ID NO.7-8.

[0011] Preferably, the salt stress resistance of the plant is improved by silencing the UBP1b.

[0012] Preferably, the plant is tomato.

[0013] A method for improving the salt stress resistance of plants, wherein the transgenic plants are obtained by knocking out the UBP1b, so as to improve the salt stress resistance of plants.

[0014] Preferably, the plant is tomato.

[0015] Through transcriptomic analysis of tomato roots under salt stress, the inventors found that within the first 12 hours of salt stress treatment, transcripts in tomato roots changed significantly in each time period and the change was greatest at 3 hours. The expression level of the UBP1b gene screened from the joint analysis of tomato salt stress transcriptome and proteome showed a downward trend in the first 6 hours of salt treatment, indicating that UBP1b may negatively regulate tomato tolerance to salt.

[0016] Based on the phenotypic and physiological indicators of the UBP1b-silenced strain under salt stress and the preliminary salt-resistance experiments on the UBP1b-knockout transgenic strain, it was concluded that UBP1b is a negative regulatory factor in regulating tomato salt resistance.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] By constructing a transient silencing expression vector for UBP1b and infecting tomato seedlings, it was found that before treatment, UBP1b silencing had no significant effect on plant phenotypes; after salt treatment, UBP1b-silenced plants showed a more obvious salt-tolerant phenotype, with lower leaf wilting and yellowing. Compared with the control, the silenced plants had higher plant height, root length, and fresh weight. Through gene editing vector construction and tomato genetic transformation, a T2 generation UBP1b knockout transgenic homozygous strain was obtained; compared with the control plants, the knockout strain had stronger salt tolerance. Based on the above phenotypic analysis results, knocking out and silencing UBP1b can improve tomato's tolerance to salt stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Virus-mediated silencing of UBP1b, A is the albino phenotype of TRV::PDS (phytoene dehydrogenase silencing), and B is the efficiency of UBP1b silencing;

[0020] Figure 2 Analysis of salt tolerance of plants with transient VIGS silencing of UBP1b, A is the phenotype of plants at 0, 3, 6, and 10 days under 300 mM NaCl treatment, B is the measurement of plant height under 300 mM NaCl treatment, C is the measurement of root length under 300 mM NaCl treatment, D is the measurement of total fresh weight under 300 mM NaCl treatment, E is the measurement of total dry weight under 300 mM NaCl treatment, data are the mean ± standard deviation of 6 biological replicates; * indicates the difference is significant at the level of p < 0.05 in the independent sample t test, *** indicates the difference is significant at the level of p < 0.001, and ns indicates that the difference is not significant;

[0021] Figure 3 The target sequence and identification of the UBP1b knockout strain, A is a schematic diagram of the UBP1b gene sequence, the target sequence is at exon 1 and 3, B is a schematic diagram of the T-DNA structure of the UBP1b gene editing vector, C is the editing site of three UBP1b knockout strains, and D is PCR verification using wild-type and UBP1b knockout strain DNA as templates;

[0022] Figure 4 This is the phenotypic diagram for the identification of UBP1b knockout strains and salt tolerance analysis during 5 days of salt treatment. WT represents wild-type tomato; K1, 2, and 3 represent three homozygous knockout plants. The scale bar is 10 cm. DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention. The experimental methods described in the embodiments of the present invention are conventional methods unless otherwise specified.

[0024] Example 1

[0025] 1. Construction of transient silencing expression vector

[0026] According to the NCBI website, refer to the tomato genome website to find the UBP1b (LOC101247634) mRNA sequence and protein sequence.

[0027]

[0028] The protein sequence is as follows: MMQQRLKQQQALMQQSLYHPALLAPPQIEPILSGNLPP GFDSSTCRSVYVGNIHPQVTEPLLQEVFSSTGPLEGCKLIKKEKSSYGFVDYFDRRSAALAIVTLNGRNLFGQPIKVNWAYTSAQREDTSSHFNIFVGDLSPEVTDATLYACFSVYPSCSDAKVMWDQKSGRSRGFGFVSFRNQQEAQSAINELTGKWLGSRQIRCNWATKGAGGIDEKQNSDAKSVVE LTSGTSDDGHDKANEDAPENSPQYTTVYVGNLSPEVTLVDLHRHFHALGAGVIEDVRIQRDKGFGFVRYSTNAEAAQAIQLGNAQFFFGKPIKCSWGSKPTLPGASSTPLPPPAVGHIPGISVTDIAAYERQLALARMGGSQALMHSQALMHSQGQRIGVASQAIYDGGYGSIAATTQPPMYY, denoted as SEQ ID NO.2.

[0029] A pair of upstream and downstream primers were designed to amplify a 225bp sequence near the upstream and downstream of the stop codon (TAG) according to the mRNA sequence, and the VIGS (virus-induced gene silencing) fragment was amplified using the cDNA of 'Micro-TOM' tomato leaves as a template. The upstream and downstream primers are:

[0030] TRV-SlUBP1b-F: 5'-GGGGACAAGTTTGTACAAAAAAGCAGGCTTCGATGGTGGTTATGGTAGTAT-3', recorded as SEQ ID NO. 3.

[0031] TRV-SlUBP1b-R: 5'-GGGGACCACTTTGTACAAGAAAGCTGGGTCCATT CTAACATCTCCTGAAG-3', recorded as SEQ ID NO. 4.

[0032] The amplified sequence is: CGATGGTGGTTATGGTAGTATTGCTGCTACAACTCAAC CACCAATGTACTACTAGTGCATAACAACAACCTGCTGCTTCTGCTCCCGGCTTTGTTTTATAGGATGCTTTTTCTCGTTAGTTTTTCGTGTCCGAAGCATATGTATGAATATGTAGCTTGTATTTTGTGTGGCAGCTAGTCCGATGGCAGTTCACTTGGATGAGCAGCTTCAGGAGATGTTAGAATG, recorded as SEQ ID NO.5.

[0033] Use Gateway TM BP Clonase TM II enzyme mixture kit (ThermoFisherScientific #11789020), using the BP method, the system is shown in Table 1, the UBP1b gene sequence was constructed into the Gateway entry vector pDONR207 to obtain UBP1b-207, and after the sequencing was correct, it was cloned and cloned by Gateway. TM LR Clonase TM II enzyme mixture (ThermoFisherScientific #11791020) kit, using the LR method, the system is shown in Table 2, the UBP1b gene sequence was constructed using UBP1b-207 onto the TRV279 vector to prepare the TRV::SlUBP1b vector, the correctly sequenced positive clone strain was mixed with 50% glycerol in a 1:1 ratio, and stored in a -80°C refrigerator, and the plasmid was stored at -20°C.

[0034] Table 1 BP cloning reaction system

[0035] Reagents Usage Gel recovery product, concentration is about 50ng / μL 0.5μL pDONR207 plasmid, concentration about 50ng / uL 0.5μL BP enzyme 0.25μL

[0036] Note: The reaction system was placed at 25°C overnight

[0037] Table 2LR cloning reaction system

[0038] Reagents Usage Gel recovery product, concentration is about 50ng / μL 0.5μL TRV279 plasmid, concentration about 50ng / uL 0.5μL LR enzyme 0.25μL

[0039] 2. Silencing UBP1b and salt treatment of silenced tomatoes

[0040] (1) TRV::SlUBP1b, control empty vector (TRV::00), and positive control plasmid (TRV::PDS) were respectively transformed into Agrobacterium GV3101.

[0041] (2) The Agrobacterium obtained in step (1) was cultured in 5 mL of liquid LB at 28° C. and 200 rpm for 16 h for activation. The liquid LB contained 50 mg / mL of Kan and 25 mg / mL of Rif.

[0042] (3) The Agrobacterium activated in step (2) was centrifuged at room temperature. After the centrifugation was completed, the supernatant was removed, and an appropriate amount of infection solution was added to each tube to resuspend the bacterial pellet, and the bacterial solution was diluted to OD600 = 0.6-0.8. The resulting bacterial solution was used for infection. The composition of the infection solution was 1.0666 g of MES, 1.016 g of MgCl2·6H2O, 750 μL of 200 mM acetosyringone, and H2O was added to make up to 500 mL.

[0043] (4) Select a 2-leaf 1-heart tomato (variety Ailsa craig) in good growth condition, inject the bacterial solution obtained in step (3) into the lower epidermis of the tomato leaves using a 1 mL syringe without a needle, and mark the leaves.

[0044] (5) The cells were cultured in the dark in an incubator for 48 hours, and then moved to a constant temperature culture phase at 28°C with a light duration of about 16 hours and a dark duration of about 8 hours. After about 15 days, the positive control (TRV::PDS) showed whitening. Figure 1 , indicating that the infection experiment was successful.

[0045] (6) After 2 weeks of infection, the silent strain TRV::SlUBP1b was treated with 300 mM NaCl salt. The NaCl solution was re-irrigated every two days and the strain was placed in a light incubator (25°C light for 16 h, 20°C dark for 8 h) to observe the phenotype. After 7 days of treatment, the growth indicators such as plant height, root length, stem thickness, and dry weight of the silent strain and the control strain were measured. The results are shown in Figure 2 .

[0046] 3. Construction of UBP1b knockout vector and genetic transformation

[0047] (I) Construction of UBP1b knockout vector

[0048] (1) gRNA sequence design: Log in to the website (http: / / www.genome.arizona.edu / crispr / CRISPRsearch.html), design gRNA target sites according to the UBP1b gene sequence, and select the target close to the first exon.

[0049] The gRNA target sequence is:

[0050] 5'-TTATCATCCTGCTCTTCTTG-3', recorded as SEQ ID NO.6;

[0051] (2) Primer design: The primers synthesized according to the gRNA target sequence are as follows:

[0052] Oligo-01F: 5'-ATTGTTATCATCCTGCTCTTCTTG-3', recorded as SEQ ID NO. 7;

[0053] Oligo-01R: 5'-CAAACAAGAAGAGCAGGATGATAA-3', recorded as SEQ ID NO.8.

[0054] (3) Oligo annealing and complementation: The above primers synthesized were dissolved in deionized water to obtain a concentration of 100uM, 5uL of each was taken and mixed, placed in a metal bath (80°C) for 15min, and naturally cooled to room temperature to complete the annealing and complementation process, thereby obtaining the Oligo-01F-01R product.

[0055] (4) Vector digestion: CRISPR-Cas9-mediated gene editing vector pCAMBIA1300-CAS9

[0056] (purchased from Shanghai Mychi Biotechnology Co., Ltd.) was digested with BsaI restriction endonuclease (purchased from NEB), and the digestion system was as follows:

[0057] Vector 4uL, BsaI 0.5uL, CutSmart buffer 1uL, deionized water 4.5uL.

[0058] The enzyme digestion reaction was placed in a 37°C water bath for 3 h, followed by a 65°C water bath for 20 min to inactivate BsaI.

[0059] (5) Ligation reaction: After the vector product from the above enzyme digestion reaction is recovered, the ligation system is prepared according to the table below.

[0060] Table 3T4 ligation reaction system

[0061] Reagents volume Enzyme digestion vector 2μL 10xNEBT4Buffer 1.5μL 10xBSA 1.5μL T4Ligase(NEB) 1μL Oligo-01F-01R product 3μL ddH2O 6μL

[0062] Note: The reaction conditions are 16°C, 2h.

[0063] (6) Transformation verification: The ligation product was transformed into DH5α competent cells. After clones were grown, colony PCR was used to verify whether they were positive clones. The positive clones were then sent for sequencing to screen the clones with correct sequencing results.

[0064] (II) Agricultural Pole Transformation

[0065] (1) Take out the competent Agrobacterium GV3101 from the -80°C freezer and wait for it to thaw;

[0066] (2) Add 5 μL of the correctly sequenced plasmid to the competent cells of Agrobacterium GV3101, place in an ice bath for 30 min, freeze in liquid nitrogen for 1 min, and then place in an ice bath for 5 min;

[0067] (3) Add 400 μL of liquid LB to the product obtained in step (2) in a clean bench, shake at 28° C., culture for 4 h, and then spread on a solid culture medium with resistance;

[0068] (4) After 2 days, perform colony verification PCR on the grown clones and save the positive strains.

[0069] 3. Tomato genetic transformation system

[0070] (1) Obtaining sterile seedlings: Select plump, uniform, fresh tomato 'Micro-TOM' seeds and rinse them repeatedly with sterile water for several times. Disinfect the tomato seeds with 70% alcohol for 30 seconds and 10% sodium hypochlorite for 10 minutes, rinse them with sterile water for 5 times, dry them with sterile filter paper, and inoculate them in seed germination medium. Cultivate them in the dark until the seeds germinate and turn white, then place them in a light-drying environment with a temperature of 25°C for 16 hours per day.

[0071] (2) Pre-culture: Cotyledons and hypocotyls were selected as explants, cut into appropriate sizes, placed on pre-culture medium, and pre-cultured for 1 day.

[0072] (3) Co-cultivation: Mix the explants with the positive Agrobacterium obtained from the Agrobacterium transformation for 5 min, absorb the excess bacterial solution with filter paper, transfer to the pre-culture medium, and culture for 2 days.

[0073] (4) Selection and subculture: The co-cultured explants are transferred to a screening medium for selection culture to form callus and adventitious buds. The callus is cut into small pieces and transferred to a stem elongation medium for subculture.

[0074] (5) Rooting and transplanting: The grown adventitious buds are transferred to a rooting medium for cultivation to form complete plants. The seedlings are then transferred to soil for training and finally transplanted to a natural environment.

[0075] 4. Identification of UBP1b knockout transgenic lines and analysis of salt stress resistance

[0076] (I) Identification of UBP1b knockout transgenic lines

[0077] Extraction of genomic DNA: (1) Weigh about 0.2g of ground tissue sample, put it into a centrifuge tube, add 1mL of 2% CTAB, mix thoroughly by inversion, and place in a 65℃ water bath for 30min to lyse the cells. (2) Centrifuge and take 750μL of supernatant (10000rpm, 10min). (3) Add an equal volume of chloroform, then shake vigorously for 3min, centrifuge and take the supernatant (12000rpm, 10min), and transfer about 500μL of supernatant to a new centrifuge tube. (4) Add an equal volume of isopropanol 500μL, shake gently and invert to mix, and let stand at -20℃ for 20min to precipitate DNA. (5) Centrifuge and discard the supernatant and keep the precipitate (12000rpm, 5min). (6) Take 400μL of 80% ethanol to wash the precipitate and resuspend it, centrifuge (12000rpm, 2min, repeat twice). (7) Dry at room temperature for 5min. (8) Add 20 μL ddH2O to dissolve the DNA and store at -20°C.

[0078] The knockout strain used the 'Micro-Tom' wild-type tomato as a negative control. Leaves of wild-type tomatoes and UBP1b knockout transgenic tomatoes were taken. The DNA extraction steps were as above, and primers were designed according to the position of the UBP1b target sequence. The above DNA was used as a template for PCR amplification. 5 μL of the PCR product (product size 502bp) was detected by 2% agarose gel electrophoresis. The remaining PCR product was then sent to Qingke Biotechnology Company for sequencing to confirm whether the editing was successful and the editing site. For the identification of T0 generation transgenic seedlings, it is also necessary to detect the Cas9 sequence by PCR to determine whether it is a positive plant. After two generations of reproduction and identification, the identification method was the same as described above, and a T2 generation homozygous transgenic strain was obtained for subsequent research.

[0079] The primer sequences used in the above PCR are as follows:

[0080] Cas9-F: 5'-TGGAGGAGGATAAGAAGCACG-3', recorded as SEQ ID NO.9;

[0081] Cas9-R: 5'-CAATGAGATTCCCGAACAGG-3', recorded as SEQ ID NO. 10;

[0082] Crispr-ubp1b-1-F: 5'-CTCTTTCAGTCTTCAACTTGTGGCA-3', recorded as SEQ ID NO.11;

[0083] Crispr-ubp1b-1-R: 5'-ACTCAACCACAGTGACTTCACCATG-3', recorded as SEQ ID NO.12;

[0084] The results of gene editing are shown in Figure 3 A.

[0085] (II) Analysis of salt stress resistance of UBP1b knockout strains

[0086] Homozygous transgenic plants with UBP1b knockout and 'Micro-Tom' wild-type tomatoes were selected, and the seed soaking, germination and sowing methods were the same as before. After they grew to 3 leaves and 1 heart, they were transplanted into soil for cultivation. Transgenic seedlings and wild-type seedlings with consistent growth were selected, and after transplanting, they were treated with 350mM NaCl salt. NaCl solution was supplemented every two days, and the seedlings were placed in a light incubator for cultivation, and plant changes were observed until phenotypic differences appeared.

[0087] result

[0088] 1. Transient silencing of UBP1b improves tomato salt stress resistance

[0089] Tomato plants transfected with the positive control (TRV::PDS) showed albino appearance, e.g. Figure 1 A, indicating that the entire infection system is effective. Subsequently, the silencing efficiency of the silenced strain was identified by fluorescence quantitative PCR, and it was found that compared with the plants infected with TRV empty vector (TRV::00), the expression of UBP1b in the UBP1b silenced strain (TRV::SlUBP1b) was significantly decreased, indicating that the VIGS-induced UBP1b gene silencing was successful. Figure 1 B.

[0090] The silencing strain was used for a 300 mM NaCl salt treatment experiment, with the TRV::00 strain as the control strain. Figure 2 As shown in A, silencing UBP1b did not have a significant effect on the growth and development of tomatoes, and the phenotypic difference was not significant; 3 days after salt treatment, the TRV::00 control plants showed slight wilt, the leaves began to droop, the leaves began to yellow, and the petioles began to soften, while the TRV::UBP1b silenced plants had no obvious salt stress symptoms; 6 days after treatment, the yellowing of the leaves of the TRV control plants intensified, the whole plant grew bent, and the leaf wilting had expanded to the whole plant, while the TRV::UBP1b silenced plants only showed slight yellowing of the old leaves, and the whole plant still grew upright; 10 days after treatment, the leaves of the TRV control plants fell seriously, and the growth of the whole plant was severely inhibited, while the TRV::UBP1b silenced plants, in comparison, grew upright and had stronger salt tolerance.

[0091] To further confirm the role of UBP1b, samples were taken 7 days after salt treatment and various growth indicators were measured. Figure 2BE showed that under salt stress, the plant height, root length and fresh and dry weight of the tomato control line TRV::00 and the silent plant TRV::UBP1b were inhibited to varying degrees; under untreated conditions, there was no significant difference in plant height, root length and fresh and dry weight between the TRV::00 control and TRV::UBP1b silent plants; under salt treatment for 7 days, compared with the TRV::00 control plants, although the total fresh weight of the TRV::UBP1b silent plants was not significant, the plant height, root length and total dry weight were significantly increased. Therefore, the TRV::UBP1b silent plants have a certain tolerance to salt stress.

[0092] In summary, the reduction of UBP1b expression level in tomato improves salt tolerance.

[0093] 2. Knockout of UBP1b improves salt stress resistance in tomatoes

[0094] (1) Identification of UBP1b knockout strains

[0095] The target sequence of UBP1b knockout is as follows Figure 3 A shows, the schematic diagram of the vector structure is as follows Figure 3 B shows that after genomic DNA extraction and PCR identification and sequencing, it was found that the homozygous knockout forms mainly include base insertion, base deletion and insertion, and the formation of a stop codon. Figure 3 C shows that the three knockout homozygous strains were numbered K1, K2, and K3 respectively.

[0096] (2) Analysis of salt resistance phenotype of knockout transgenic plants

[0097] Before treatment, there was no significant difference in growth phenotype between the UBP1b knockout transgenic line and the wild type. After 1 day of saline irrigation, the WT and knockout plants did not show obvious salt damage phenotypes. After 5 days of continued saline irrigation, the WT plants showed large-scale wilting and yellowing and leaf shrinkage, but the knockout plants only showed slight yellowing and partial inward curling of the leaves, such as Figure 4 This indicates that the knockout plants have a higher tolerance to high salt than the control group. Therefore, knocking out the UBP1b gene can improve the salt resistance of tomato plants.

[0098] It should be noted that when the claims of the present invention involve numerical ranges, it should be understood that the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. In order to avoid redundancy, the present invention describes a preferred embodiment.

[0099] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0100] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. The application of UBP1b in improving the ability of plants to resist salt stress, characterized in that: The nucleotide sequence of UBP1b is shown in SEQ ID NO.1; A transgenic plant is obtained by knocking out the UBP1b, so as to improve the plant's ability to resist salt stress; By silencing the UBP1b, the plant's resistance to salt stress is improved; The plant is tomato.

2. The use according to claim 1, characterized in that: Ways to knock out the UBP1b include base insertion, base deletion, and insertion or formation of a stop codon.

3. The use according to claim 1, characterized in that: The method for preparing the transgenic plant comprises the following steps: designing a knockout target sequence according to the UBP1b gene sequence, constructing the knockout target sequence into a gene editing vector pCAMBIA1300-CAS9, and obtaining the transgenic plant by genetic transformation.

4. The use according to claim 3, characterized in that: The knockout target sequence is 5'-TTATCATCCTGCTCTTCTTG-3'.

5. The use according to claim 3, characterized in that: The primer sequences for constructing the target sequence into the gene editing vector are shown in SEQ ID NO.7-8.

6. A method for improving the salt stress resistance of plants, characterized in that: A transgenic plant is obtained by knocking out the UBP1b described in claim 1 to improve the plant's resistance to salt stress; The plant is tomato.

Images