IbFLZ9 gene and application of IbFLZ9 gene in regulation and control of growth of sweet potato stems and vines

Abstract

The invention provides an IbFLZ9 gene and application thereof in regulation and control of growth of sweet potato vines, and belongs to the technical field of gene engineering and sweet potato breeding. The invention provides an IbFLZ9 gene for regulating and controlling growth of sweet potato vines. The nucleotide sequence of the IbFLZ9 gene is shown as SEQ ID NO. 1. Growth of sweet potato vines can be remarkably inhibited by overexpressing the IbFLZ9 gene, and growth of sweet potato vines can be remarkably promoted by inhibiting expression of the IbFLZ9 gene through a gene knockout technology. A new sweet potato variety which is moderate in vine length and convenient to mechanically harvest can be created by regulating and controlling the expression abundance of the IbFLZ9 gene, and a new gene resource and a new breeding technology are provided for improving the characters of the overground part of the sweet potato.

Description

TECHNICAL FIELD

[0001] The present application relates to the fields of genetic engineering and sweet potato breeding, and particularly relates to an IbFLZ9 gene and application thereof in regulating stem and vine growth of sweet potato. BACKGROUND

[0002] Sweet potato (Ipomoea batatas (L.) Lam.) is an important food and industrial crop in China. However, the mechanical harvesting process is greatly affected by the long stem and vine length. In addition, the overlong stem and vine will intertwine and overlap, resulting in that part of the leaves cannot effectively perform photosynthesis, thereby affecting the biomass accumulation of tubers. Therefore, effectively regulating the stem and vine length to prevent overgrowth is of great significance to improve the mechanical harvesting efficiency and yield of sweet potato.

[0003] Transcriptional regulators play a key role in crop genetic engineering, because their overexpression or functional interference can systematically up-regulate or down-regulate gene clusters related to growth and development, thereby regulating key agronomic traits such as plant height. Among them, the FCS-like zinc finger (FLZ) family is a C2-C2 zinc finger protein unique to plants, and these proteins show significant response to plant hormones, nutritional status and various abiotic stresses. Although their role in stress adaptation and growth regulation has been established, so far there has been no report on the regulation of FLZ on the stem and vine growth of sweet potato. SUMMARY

[0004] The purpose of the present application is to provide an application of IbFLZ9 gene in regulating stem and vine growth of sweet potato. By overexpressing IbFLZ9 gene, the stem and vine length of sweet potato can be significantly shortened, and by gene knockout technology, the stem and vine growth of sweet potato can be significantly promoted, thereby providing a new genetic resource and breeding technology for the improvement of stem and vine length of sweet potato.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0006] The present application provides an IbFLZ9 gene for regulating stem and vine growth of sweet potato, wherein the nucleotide sequence of the IbFLZ9 gene is shown as SEQ ID NO. 1.

[0007] The present application also provides a protein encoded by the above-mentioned IbFLZ9 gene, wherein the amino acid sequence of the protein is shown as SEQ ID NO. 4.

[0008] The present application also provides a recombinant plasmid or recombinant bacteria containing the above-mentioned IbFLZ9 gene.

[0009] The present application also provides an application of the above-mentioned IbFLZ9 gene or the above-mentioned recombinant plasmid or recombinant bacteria in regulating stem and vine growth of sweet potato.

[0010] Preferably, overexpression of IbFLZ9 gene can shorten the stem of sweet potato.

[0011] Preferably, inhibition of IbFLZ9 gene can elongate the stem of sweet potato.

[0012] Beneficial effects:

[0013] The present application discloses that IbFLZ9 gene is a key gene for regulating the growth of sweet potato stem. An effective technical means for directional change of sweet potato stem length by regulating the expression level (overexpression or inhibition) of IbFLZ9 gene is provided. A feasible method for cultivating new short-stem sweet potato varieties by overexpression of IbFLZ9 gene is established, which provides important genetic resources and core technology for effectively regulating the length of sweet potato stem, preventing overgrowth, and improving the efficiency and yield of mechanical harvesting of sweet potato. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 Agarose gel electrophoresis map for cloning of sweet potato IbFLZ9 gene in Example 1;

[0015] Figure 2 Structure diagram of IbFLZ9-OE overexpression recombinant plasmid in Example 2;

[0016] Figure 3 Structure diagram of IbFLZ9 gene knockout vector plasmid in Example 2;

[0017] Figure 4 PCR detection map of IbFLZ9 overexpression transgenic sweet potato in Example 4;

[0018] Figure 5 Sequencing results of IbFLZ9 gene knockout transgenic sweet potato in Example 4;

[0019] Figure 6 Expression amount analysis of IbFLZ9 in transgenic sweet potato in Example 5;

[0020] Figure 7 Phenotype and length measurement of wild type and transgenic sweet potato stem in Example 6. DETAILED DESCRIPTION

[0021] The technical solutions provided by the present application will be described in detail below in conjunction with the examples, but they should not be understood as limiting the scope of protection of the present application.

[0022] Example 1: Cloning of sweet potato IbFLZ9 gene

[0023] 1. Extraction of total RNA from sweet potato leaves

[0024] Trizol method RNA extraction kit (Shanghai Jierui, GK3016) to extract total RNA, the specific steps are as follows:

[0025] (1) take sweet potato varieties Xu Zisuo 8 tender leaves (about 300mg), in liquid nitrogen grinding into powder, while the liquid nitrogen has not yet evaporated, the powder is transferred to 1.5mL sterile RNAase-free centrifuge tube. Every 100mg sample added 1mL RnaEx TM (Trizol), vortex for 30s, room temperature for 5min, to fully lysis sample.

[0026] (2) according to every 1mL RnaEx TM Add 200μL chloroform, shake well mixed 30s, room temperature for 5min.

[0027] (3) precool centrifuge 4℃, 12000rpm, centrifugation 10min, to make the solution fully layered.

[0028] (4) with the gun head to 500μL dissolved in RNA supernatant, carefully transfer to a new 1.5mL RNase-free centrifuge tube, add 200μL anhydrous ethanol, mix well.

[0029] (5) the solution (including precipitate) in (4) is transferred to the GenClean column placed in 2mL collection tube, room temperature for 2min, 8000rpm centrifugation 1min.

[0030] (6) carefully take out the column, discard the waste liquid in the collection tube, put the column back into the collection tube, add 600uL buffer RWA, 8000rpm, room temperature centrifugation 30s, discard the waste liquid in the collection tube.

[0031] (7) repeat step (6) once, carefully take out the column, discard the waste liquid in the collection tube, put the column back into the collection tube, 12000rpm, room temperature centrifugation 1min.

[0032] (8) carefully take out the column, placed in 1.5mL sterile RNase-free centrifuge tube, in the central column membrane suspended drop 50μL DEPC-H2O, 65℃ for 2min.

[0033] (9) 12000rpm, room temperature centrifugation 2min, the solution in the collection tube is the total RNA of sweet potato leaves.

[0034] 2, with total RNA of sweet potato leaves reverse transcription to form cDNA

[0035] The total RNA extracted above was reverse transcribed into cDNA by First-Strand cDNA Synthesis Kit kit (Toyobo, FSQ301) according to the following procedure:

[0036] (1) Take 1 μg of total RNA in a sterile RNAase-free PCR tube, heat denature at 65°C for 5 min, and then immediately cool on ice.

[0037] (2) Add 2 μL of 4x DN Master Mix (with gDNA Remover) on ice, and add RNase-Free H2O to a final volume of 8 μL. Mix the reaction solution gently, and then incubate at 37°C for 5 min.

[0038] (3) Then, add 2 μL of 5x RT Master Mix II on ice. Mix the reaction solution gently, and then perform reverse transcription according to the following temperature: 37°C for 15 min, 50°C for 5 min, 98°C for 5 min, and 4°C storage.

[0039] The resulting product is diluted 10 times with RNase-Free water and used in subsequent experiments or stored at -20°C.

[0040] 3. Amplification of CDS sequence of IbFLZ9 gene

[0041] The CDS full-length sequence of sweet potato IbFLZ9 gene was obtained according to the sweet potato genome (Beauregard V1.0), and the upstream and downstream primers for CDS amplification were designed using Primer 5 online software:

[0042] IbFLZ9-F: 5’–ATGCTGGGCAAGAGATTAAACC–3’ (SEQ ID NO. 2);

[0043] IbFLZ9-R: 5’–TCAGATGGCCAGAATTCCGGTT–3’ (SEQ ID NO. 3).

[0044] The above 10-fold diluted cDNA was used as a template to prepare a 50 μL reaction system (Takara, R045A) on ice: including 2 μL of template cDNA, 25 μL of PrimeSTAR Max Premix (2x), 1 μL of upstream and downstream primers, and 21 μL of ddH2O. After loading, mix and centrifuge slightly, and then place in a PCR instrument to perform amplification reaction: 98°C for 10 s, 58°C for 15 s, 72°C for 30 s, 32 cycles; 72°C for 5 min; and 4°C storage.

[0045] PCR products were electrophoresed on agarose gel, and the target fragments were recovered from the gel (NucleoSpin®, DC221-01) and ligated into sequencing vectors. Positive single clones were selected for sequencing, and the nucleotide sequence of the IbFLZ9 gene was obtained as shown in SEQ ID NO. 1, and the amino acid sequence encoded by the gene was as shown in SEQ ID NO. 4. Figure 1 ) The sequencing vector was ligated, and positive single clones were selected for sequencing, and the nucleotide sequence of the IbFLZ9 gene was obtained as shown in SEQ ID NO. 1, and the amino acid sequence encoded by the gene was as shown in SEQ ID NO. 4.

[0046] SEQ ID NO. 1:

[0047] ATGCTGGGCAAGAGATTAAACCCGGTGGCCGGAAAGATCGCCGGCGGGCCGGCAAGCCCGAGAAGTCCTTTGAAAAGTTTCGATCTTGGAGGGGTTGGGCTGGCGATTGTGGCCGCCCTGGAAAAATCTTGCGAGAGAGGGGAGATTGCGGGGAGAAAGGTGGTTTGTAGCCGGAATTCGCGGCGGTCGGTGCCGATTCCGGTGAGCTCCGGGAGGATTCCGGCGAGAATTGTGGGGAGTTTTGGACGGAGCCTAGAGGAGGAAGAAGAAGAAGAGGAGTATACGGTGGTGACTTGCCGCGGCTCCGACAATAAACCGTACACTAAAGTCTACGGCGAAGTCCCGAGCTCCAGAAACCCGACCAGAAACAACCGACCGAGCGTTTTCATGATTTCTCCGGCGAGGCTCGGCGATATTCCGGCGTGCCCGGATTCCGATTTTCTCAGCTCCTGTCATTTATGCCGGAAAAAACTCTCCGGCAAAGATATTTACATGTACAGGGGTGAAACGGCGTTTTGTAGCACGGAGTGTAGATATCGGCAGATAGTGATGGACGAGCACAAAGAGAAGTGCAGTTCGGAGATTTCTAGGTCCGCCGATATCTCGAGCTCCCCTTACACAAACGGCCAGATGTTTTCAACCGGA ATTCTGGCCATCTGA

[0048] SEQ ID NO. 4:

[0049] MLGKRLNPVAGKIAGGPASPRSPLKSFDLGGVGLAIVAALEKSCERGEIAGRKVVCSRNSRRSVPIPVSSGRIPARIVGSFGRSLEEEEEEEEYTVVTCRGSDNKPYTKVYGEVPSSRNPTRNNRPSVFMISPARLGDIPACPDSDFLSSCHLCRKKLSGKDIYMYRGETAFCSTECRYRQIVMDEHKEKCSSEISRSADISSSPYTNGQMFSTGILAI

[0050] Construction of recombinant expression vector of Example 2

[0051] 1. Construction of IbFLZ9 overexpression vector

[0052] According to the restriction enzyme sites (Kpn I and BamH I) available in the expression vector pCAMBIA1301-DsRed, the homologous arm primers for the construction of IbFLZ9 overexpression vector were designed:

[0053] IbFLZ9-OE-F:

[0054] 5’–TACAATTACAATTAGGATCCATGCTGGGCAAGAGATTAA ACC–3’(SEQ ID NO.5);

[0055] IbFLZ9-OE-R:

[0056] 5’–TGGTCGACGGCGCTGGTACCTCAGATGGCCAGAATTCC GGTT–3’(SEQ ID NO.6)。

[0057] The above primers with restriction enzyme sites were used for PCR amplification to obtain a DNA fragment containing the complete coding sequence of IbFLZ9, and the amplification product was purified and recovered. Meanwhile, the pCAMBIA1301-DsRed empty vector was double-digested (Kpn I and BamH I, Thermo company); the purified DNA fragment and the digested empty vector were connected using 2x MultiF Seamless Assembly Mix seamless ligase of ABclonal company, and then the recombinant plasmid was transformed into E. coli DH5a competent cells and sent to Shanghai Qikeng Sequencing Company for sequencing to obtain the accurate IbFLZ9-OE overexpression recombinant plasmid (pCAMBIA1301-DsRed-IbFLZ9-OE). Figure 2

[0058] 2. Construction of IbFLZ9 gene knockout vector

[0059] ​According to the CDS sequence of IbFLZ9 gene, the gRNA sequence was designed by targetDesign tool (http: / / skl.scau.edu.cn / targetdesign / ), and the off-target analysis was performed by Cas Offinder (http: / / www.rgenome.net / cas-offinder / ). Based on pHSE401 and pCBC-DT1T2 vectors, four primers (IbFLZ9-DT1-BsF, IbFLZ9-DT1-F0, IbFLZ9-DT2-R0 and IbFLZ9-DT2-BsR) for double target were designed and PCR amplified with the vector pCBC-DT1T2 as a template. Specifically, according to the Bsa I enzyme cutting site of pHSE401 vector, the homologous arm cloning primer containing gRNA target sequence was designed:

[0060] IbFLZ9-DT1-BsF:

[0061] 5’–ATATATGGTCTCGATTGTGGCCGGAAAGATCGCCGG–3’(SEQ ID NO.7);

[0062] IbFLZ9-DT1-F0:

[0063] 5’–TGTGGCCGGAAAGATCGCCGGGTTTTAGAGCTAGAAAT AGC–3’(SEQ ID NO.8);

[0064] IbFLZ9-DT2-R0:

[0065] 5’–AACCAATCGCCAGCCCAACCCCCAATCTCTTAGTCGACT CTAC–3’(SEQ ID NO.9);

[0066] IbFLZ9-DT2-BsR:

[0067] 5’–ATTATTGGTCTCGAAACCAATCGCCAGCCCAACCCCCAA–3’(SEQ ID NO.10)。

[0068] The 626 bp fragment containing the target was obtained by PCR amplification with the above-mentioned primer with homologous arm, and after gel recovery and purification, the fragment was ligated with the Bsa I enzyme cut empty plasmid pHSE401 by enzyme cutting and ligation method, and the recombinant plasmid was transformed into E. coli DH5α competent cells and sent to Genscript for sequencing, and finally the IbFLZ9 gene knockout vector plasmid ( Figure 3 ) was obtained.

[0069] Example 3 Agrobacterium-mediated sweet potato genetic transformation

[0070] 1. Transformation of Agrobacterium with recombinant expression vector

[0071] The sequencing-verified IbFLZ9-OE and IbFLZ9-CRIPSR plasmids were transformed into Agrobacterium EHA105, respectively: 1.5 μL of plasmid was mixed with 50 μL of competent cells in ice bath for 30 min, then quickly frozen in liquid nitrogen for 5 min, and then heat-shocked at 37 °C for 5 min, and then ice-bathed for 2 min; 600 μL of LB medium was added and mixed, and then recovered at 28 °C, 200 rpm for 2 h, and then spread on LB plates and cultured at 28 °C for 2 d; and then the single colonies that grew were verified by PCR.

[0072] 2. Induction and subculture of sweet potato embryogenic callus

[0073] (1) About 20 cm long sweet potato seedlings were obtained by germination of tubers, and 0.5 cm long stem tips were cut from the seedlings, which were first repeatedly washed with pure water, then surface-sterilized with 70% ethanol for 30 s, then immersed in 0.1% mercury sulfate solution for 3 min, and finally washed with sterile water for 4 times to completely remove the residual sterilizing agent. The stem tip meristems were peeled under a biological microscope, and then inoculated on MS solid medium containing 2.0 mg / L 2,4-D, and then cultured at 28 °C in the dark for 4 weeks to induce the formation of embryogenic callus.

[0074] (2) During subculture, the callus was transferred to fresh MS medium with the same hormone concentration, and then every 20 d, the callus with good state was selected, and then the non-embryogenic tissue was removed, and then the callus was divided into uniform tissue blocks for continuous culture to achieve continuous propagation.

[0075] 3. Infection and co-culture

[0076] (1) The sweet potato embryogenic callus was ground to about 1 mm in size 1 d in advance, and then pre-cultured in MS liquid medium containing 2.0 mg / L 2,4-D as a transformation receptor.

[0077] (2) The positive Agrobacterium identified by PCR was inoculated in 15 mL of LB liquid medium containing 100 mg / L kanamycin (Kan) and 100 mg / L rifampicin (Rif), and then cultured at 28 °C, 200 rpm until the OD 600 reached about 0.7, and then centrifuged at 4000 rpm for 10 min to collect the bacterial cells, which were resuspended in MS liquid medium and then centrifuged again for washing; finally, the OD 600 of the bacterial liquid was adjusted to 0.5 with MS medium, and then acetyl-syringone (AS, final concentration 30 mg / L) was added to prepare an Agrobacterium infection bacterial liquid.

[0078] (3) The pre-cultured sweet potato embryogenic callus was added to the bacterial infection solution, wrapped with tin foil to avoid light, and slowly shaken for 30 min, then ultrasonically treated for 15 s; the bacterial solution was discarded, and the cell mass was gently transferred to the surface of MS solid medium (containing 30 mg / L AS + 2.0 mg / L 2,4-D) coated with sterile filter paper using a medicine spoon combined with tweezers, and cultured in the dark at 28°C for 3 d to complete the co-culture.

[0079] 4. Decontamination, selection culture and regeneration of the transgenic plants

[0080] (1) After co-culture, the embryogenic cell mass was scraped into a sterile triangular flask and repeatedly washed with sterile water for 6 times (blown with a pipette to assist) until the liquid was clear, and the water was absorbed with sterile filter paper; then the cell mass was transferred to MSD medium containing 200 mg / L Cef, and strictly delayed culture was performed for 1 week to remove Agrobacterium and promote tissue recovery.

[0081] (2) The callus after delay culture was transferred to MSD + 10 mg / L Hyg + 200 mg / L Cef selection medium, and subcultured every 2 weeks, and non-embryogenic tissues were removed, and two rounds of continuous selection were performed.

[0082] (3) The resistant callus was transferred to MS + 1 mg / L ABA + 200 mg / L Cef medium, and cultured under light for 1-2 weeks to induce the formation of embryoids.

[0083] (4) The mature somatic embryos were transferred to MS + 10 mg / L Hyg + 200 mg / L Cef medium, and cultured for 2 months to obtain complete regenerated plants.

[0084] Example 4. Molecular identification of positive plants

[0085] 1. Extraction of transgenic sweet potato DNA

[0086] The leaf of the regenerated sweet potato plant was taken, and the improved CTAB method was used to extract the sweet potato genomic DNA, and the specific steps were as follows:

[0087] (1) About 10 mg of sample was added to a pre-cooled 2 mL sterile centrifuge tube with a small amount of PVPP, and immediately ground into powder with a grinder after quick freezing in liquid nitrogen.

[0088] (2) 600 μL of 65°C preheated CTAB buffer was added to the centrifuge tube, vortexed and incubated at 65°C for 1 h, and inverted and mixed several times every 20 min during the incubation to promote complete lysis of the tissue.

[0089] (3) 600 μL of chloroform-isoamyl alcohol (24:1) mixed solution was added, vortexed to form a milky emulsion, and after balancing, centrifuged at 12000 rpm at room temperature for 10 min to separate the organic phase and the aqueous phase.

[0090] (4) Take 400 μL supernatant (avoiding the middle layer impurities), add 300 μL -20°C pre-cooled isopentanol and 10 μL 3 mol / L sodium acetate into a 1.5 mL centrifuge tube, mix gently by inverting until flocculent precipitate appears, centrifuge at 12000 rpm for 5 min at room temperature.

[0091] (5) Discard the supernatant, add 800 μL -20°C pre-cooled 70% ethanol, centrifuge at 12000 rpm for 1 min at room temperature, discard the supernatant.

[0092] (6) Repeat step (5) twice (until the precipitate is white), after discarding the supernatant, open the cover and blow dry for 10 min on the clean bench.

[0093] (7) Add 100 μL TE buffer, dissolve the DNA by flicking the tube wall; add 1 μL 10 mg / mL RNase A, incubate at 37°C for 1 h to degrade RNA.

[0094] 2. PCR amplification identification of overexpression lines

[0095] Using IbFLZ9 overexpression transgenic sweet potato DNA as a template, IbFLZ9-OE-tF / tR (overexpression) was amplified by PCR using vector-specific detection primers, and after gel electrophoresis verification, it was confirmed that IbFLZ9 gene was successfully overexpressed in sweet potato ( Figure 4 ). Positive plants IbFLZ9-OE7, 12, 31 (overexpression) were selected for subsequent research. The vector-specific detection primer sequences are as follows:

[0096] IbFLZ9-OE-tF: 5’–AGGACACGCTCGAGTATAAGAGC–3’ (SEQ ID NO. 11);

[0097] IbFLZ9-OE-tR: 5’–GGACTCTAGGGACTAGTCCCG–3’ (SEQ ID NO. 12).

[0098] 3. Hi-TOM sequencing identification of gene knockout lines

[0099] Using IbFLZ9 gene knockout sweet potato DNA as a template, IbFLZ9-CRIPSR-tF / tR was amplified by PCR using vector-specific detection primers, and after gel electrophoresis verification, the PCR product was subjected to high-throughput sequencing analysis (High-Throughput Mutation Analysis, Hi-TOM), and the gene knockout lines were determined by analyzing the sequencing results ( Figure 5 ).

[0100] Example 5 Real-time fluorescence quantitative PCR (RT-qPCR) detection of the expression level of the transformed gene

[0101] Total RNA was extracted from leaves of overexpression lines (OE1, 7, 12, 13, 28, and 31) and knockout lines (CR1, 3, 4, 6, 7, 9, 10, and 11), and cDNA was synthesized using the Toyobo Reverse Transcription Kit (FSQ301). IbFLZ9 gene-specific RT-qPCR primers (F: 5′–TCATGATTTCTCCGGCGAGG–3′, SEQ ID NO. 13; R: 5′–GGCGGACCTAGAAATCTCCG–3′, SEQ ID NO. 14) were designed online using Primer 5. The expression level of IbFLZ9 was detected using a real-time fluorescence quantitative PCR Master Mix Kit (Toyobo, QPK-201) and an ABI StepOne Plus PCR System (ABI, QuantStudioTM 6Flex). RT-qPCR reaction conditions: 95°C pre-denaturation for 3 min; 40 cycles (95°C for 15 s, 60°C for 15 s, 72°C for 30 s, with fluorescence collected during the extension phase at 72°C). Relative gene expression was calculated using the ΔΔCt method, with IbActin as the internal reference for normalization. Three biological replicates were performed, and the entire process was performed on ice.

[0102] The results are as follows Figure 6 As shown (a is the overexpression line, b is the knockout expression line), compared with the wild-type sweet potato WT, the expression level of IbFLZ9 in the overexpression transgenic lines (OE7, 12, 31) was significantly upregulated (P<0.05); the expression level of IbFLZ9 in the knockout expression lines (CR1, 6, 11) was significantly decreased (P<0.05).

[0103] Example 6 IbFLZ9 transgenic sweet potato vine length determination

[0104] 90 days after planting, the vine length (cm) of the sweet potato wild-type WT and transgenic plants was measured using a tape measure.

[0105] like Figure 7 As shown (a is the phenotypic diagram, b is the bar analysis diagram), compared with the wild type WT, the vine length of the overexpression transgenic lines OE7, 12, and 31 was significantly reduced by 88.17% to 91.61% (P<0.01); while the gene knockout lines CR1, 6, and 11 were significantly increased by 6.12% to 23.31% (P<0.05), indicating that the IbFLZ9 gene negatively regulates the sweet potato vine length growth.

[0106] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the protection scope of the present application.

Claims

1. An IbFLZ9 gene for regulating the growth of sweet potato stems and vines, characterized in that: The nucleotide sequence of the IbFLZ9 gene is shown in SEQ ID NO.

1.

2. The protein encoded by the IbFLZ9 gene according to claim 1, wherein The amino acid sequence of the protein is shown in SEQ ID NO.

4.

3. A recombinant plasmid or recombinant bacterium containing the IbFLZ9 gene according to claim 1.

4. Use of the IbFLZ9 gene according to claim 1 or the recombinant plasmid or recombinant bacteria according to claim 3 in regulating the growth of sweet potato stems and vines.

5. The use according to claim 4, characterized in that Overexpression of the IbFLZ9 gene can shorten the sweet potato stems.

6. The use according to claim 4, characterized in that Inhibiting the IbFLZ9 gene can cause sweet potato stems to elongate.

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