Lagerstroemia indica LfiGAI1 gene and application thereof in regulation and control of plant height

Abstract

The invention provides a lagerstroemia indica LfiGAI1 gene and application of the lagerstroemia indica LfiGAI1 gene in regulation and control of plant height, and belongs to the technical field of molecular biology The invention provides the gene LfiGAI1, the gene LfiGAI1 can inhibit division and elongation of crape myrtle cells so as to regulate and control the plant height growth of crape myrtle, overexpression of the gene in tobacco can shorten the internode length of an overexpression strain and significantly reduce the plant height, which indicates that the gene LfiGAI1 can inhibit elongation of the crape myrtle cells so as to regulate and control the plant height of crape myrtle, and the growth of crape myrtle plants is promoted. The method has important significance on breeding of plant varieties with specific plant heights.

Description

Technical Field

[0001] The present invention relates to the field of molecular biotechnology, in particular to a Lagerstroemia indica LfiGAI1 gene and an application thereof in regulating plant strain growth. Background Art

[0002] Crape myrtle (Lagerstroemia indica L.) is a deciduous small tree or shrub of the genus Lagerstroemia in the Lythraceae family, widely distributed across Asia, America, and Oceania. It typically grows 2-7 meters tall, with smooth, clean bark and a often twisted trunk. Its young branches are quadrangular, and its leaves are elliptical or obovate, papery. Its panicles are terminal, and its flowers are rich in colors, including purple, red, pink, and white. The petals are wrinkled, and the flowering period lasts for 3-4 months, from summer to autumn, earning it the nickname "Hundred-Day Red." Crape myrtle is highly adaptable, preferring sunny, well-drained environments. It is drought-tolerant and cold-resistant, and has a relaxed soil profile, growing in both calcareous and acidic soils. Therefore, it holds a prominent place in landscaping, garden landscaping, and bonsai art. Furthermore, its leaves and branches have a remarkable ability to retain airborne particulate matter, offering significant ecological benefits, making it a highly desirable tree species with both ornamental and environmental benefits.

[0003] Plant height is a key characteristic affecting the garden application and ornamental value of crape myrtles. In landscape design, different scenarios require different plant forms. For example, as a street tree or large green plant, a taller plant is needed to create a visual focal point, while as a garden bonsai or small landscape, a dwarf variety is needed to adapt to the spatial scale. Traditionally, plant height control has relied on horticultural pruning, but manual pruning is time-consuming and labor-intensive, with limited effectiveness. It is difficult to precisely control plant proportions, and excessive pruning can also affect plant health. Genetic manipulation of plant height can fundamentally optimize the natural growth characteristics of crape myrtles and cultivate varieties that meet diverse needs. For example, short, compact varieties reduce maintenance costs and extend ornamental life, while tall, upright varieties enhance their ecological barrier function. Furthermore, effective plant height management can improve the efficiency of crape myrtles' layered use of vertical space, enhance their landscape coordination with other plants, and promote photosynthetic efficiency and stress resistance, offering new possibilities for urban greening, ecological restoration, and the development of specialty nursery industries. Summary of the Invention

[0004] The purpose of the present invention is to provide the Lagerstroemia indica LfiGAI1 gene and its application in regulating plant height, which is of great significance for the breeding of plant varieties with specific plant height.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a crape myrtle plant height regulating gene, the nucleotide sequence of the crape myrtle plant height regulating gene is shown as SEQ ID NO.1.

[0007] The present invention provides a primer set for amplifying the above-mentioned Lagerstroemia plant height regulating gene, comprising an upstream primer as shown in SEQ ID NO.6 and a downstream primer as shown in SEQ ID NO.7.

[0008] The present invention provides a gene overexpression recombinant vector, wherein the gene overexpression recombinant vector targets the crape myrtle plant height regulating gene or contains the crape myrtle plant height regulating gene.

[0009] The present invention provides a gene knockdown recombinant vector, wherein the gene knockdown recombinant vector targets the crape myrtle plant height regulating gene.

[0010] The present invention provides a gene regulation engineering bacterium containing the above-mentioned gene overexpression recombinant vector or gene knockdown recombinant vector.

[0011] The present invention provides a plant height regulation kit, which contains the above-mentioned gene overexpression recombinant vector, gene knockdown recombinant vector or gene regulation engineering bacteria.

[0012] The present invention provides the use of the above-mentioned crape myrtle plant height regulating gene, primer set, gene overexpression recombinant vector, gene knockdown recombinant vector or gene regulation engineering bacteria in preparing a plant height regulating product.

[0013] Preferably, the plants include crape myrtle and tobacco.

[0014] The present invention provides a genetically engineered plant containing the over-expressed crape myrtle plant height regulating gene.

[0015] The present invention provides a genetically engineered plant, wherein the genome of the plant contains the crape myrtle plant height regulating gene, and the expression of the crape myrtle plant height regulating gene is suppressed.

[0016] Beneficial effects of the present invention:

[0017] The present invention provides a gene LfiGAI1, which can inhibit the division and elongation of crape myrtle cells and thus regulate the growth of crape myrtle plant height. Overexpression of the gene in tobacco can shorten the internode length of the overexpressing strain and significantly shorten the plant height, indicating that GAI1 can inhibit the elongation of crape myrtle cells and thus regulate the plant height of crape myrtle, which is of great significance for the breeding of plant varieties with specific plant heights. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the gel electrophoresis diagram of LfiGAI1 gene cloning; M: DL 2000Marker;

[0019] Figure 2 is the phylogenetic tree diagram;

[0020] Figure 3 Figure 2 shows the expression pattern of the LfiGAI1 gene in different tissues of tall and dwarf crape myrtles. S_SAM: stem apex of tall crape myrtles; D_SAM: stem apex of dwarf crape myrtles; S_TS: tender stem of tall crape myrtles; D_TS: tender stem of dwarf crape myrtles; S_MS: mature stem of tall crape myrtles; D_MS: mature stem of dwarf crape myrtles. Data are the mean ± SD of three biological measurements. * indicates significant differences (one-way analysis of variance, *: p < 0.05, **: p < 0.01, ***: p < 0.001).

[0021] Figure 4 Gel electrophoresis diagram of the overexpression vector construction results; M: DL2000Marker;

[0022] Figure 5 This is the gel electrophoresis diagram of the overexpression vector transformed into Agrobacterium GV3101; M: DL2000Marker; 1-5 are 1300 empty vectors, 6-15 are LfiGAI1 overexpression vectors;

[0023] Figure 6 This is the subcellular localization map of LfiGAI1::GFP; DAPI: DAPI staining; GFP: excitation fluorescence; Bright: the result observed under bright field; Merge: the composite result of overlapping DAPI, GFP and bright field;

[0024] Figure 7 Screening results of 1300 empty transgenic tobacco and LfiGAI1 transgenic tobacco; A: DNA identification of Superpromoter::GFP transgenic tobacco; B: DNA identification of Super promoter::LfiGAI1::GFP transgenic tobacco; M: DL2000 Marker;

[0025] Figure 8 This is the real-time fluorescence quantitative result of LfiGAI1 gene expression in 1300 empty transgenic tobacco and LfiGAI1 transgenic big-leaf tobacco;

[0026] Figure 9 This is the plant height change diagram of LfiGAI1 transgenic large-leaf tobacco;

[0027] Figure 10 Statistical diagram of plant height-related phenotypic traits of 1300 empty transgenic tobacco and LfiGAI1 transgenic large-leaf tobacco; data are the mean ± standard deviation of three biological measurements, *, ** represent significant differences (one-way analysis of variance, *: p < 0.05, **: p < 0.01);

[0028] Figure 11These are paraffin sections of the transverse and longitudinal sections of the stem segments of 1300 empty transgenic tobacco and LfiGAI1 transgenic big-leaf tobacco;

[0029] Figure 12 Statistical analysis of the pith and xylem cell sizes in transverse and longitudinal sections of 1300 empty transgenic tobacco and LfiGAI1 transgenic broadleaf tobacco stem segments; data are the mean ± standard deviation of three biological measurements, *, ** represent significant differences (one-way analysis of variance, *: p < 0.05, **: p < 0.01). DETAILED DESCRIPTION

[0030] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0031] The nucleotide sequence of LfiGAI1 in the embodiment is shown in SEQ ID NO.1:

[0032]

[0033] Example 1

[0034] 1.1 RNA extraction from stem tips, young stems, and mature stems of Crape Myrtle

[0035] Obtaining the full-length cDNA sequence of the Lagerstroemia indica LfiGAI1 gene: The stem tips, tender stems and mature stems of the tall Lagerstroemia indica S4 and the dwarf Lagerstroemia indica D043 from the Lagerstroemia indica plant height separation progeny population were used as materials, and the total RNA from each part was extracted using the RNAsimple Total RNA Kit (TIANGEN).

[0036] 1.2 cDNA Synthesis

[0037] According to the instructions of the HiScript IIQ RT SuperMix for qPCR (+gDNAwiper) (vazyme) reverse transcription premix kit, a two-step method was used to remove genomic DNA and perform reverse transcription reaction to obtain cDNAs from various parts of tall and dwarf crape myrtle.

[0038] 2. Expression pattern of the LfiGAI1 gene

[0039] 2.1 qRT-PCR primer design

[0040] The crape myrtle internal reference gene EF-1α was used as the internal reference gene. qRT-PCR primers (Table 1) were designed online using NCBI (https: / / blast.ncbi.nlm.nih.gov / Blast.cgi) and synthesized by Qingke (Beijing).

[0041] Table 1. Real-time quantitative gene primers

[0042]

[0043] 2.2qRT-PCR reaction

[0044] According to the ChamQ Universal SYBR qPCR Master Mix universal high-sensitivity dye-based quantitative PCR detection kit, 15 μL qRT-PCR reaction system was prepared (Table 2) and three technical replicates were set. TM 5 Fluorescence quantitative PCR system completed, using 2 -△△CT Methods The data were analyzed.

[0045] Table 2. qRT-PCR reaction system

[0046]

[0047] 3. Subcellular Localization

[0048] 3.1 Construction of LfiGAI1 fusion expression vector

[0049] 3.1.1 Amplification and recovery of target genes

[0050] The cDNA of the tender stem of tall and dwarf crape myrtle was used as amplification template, and the LfiGAI1 open reading frame was amplified with 2×KeyPo SE Master Mix (DyePlus). The amplification reaction was carried out according to the reagent instructions, and the amplified products were detected by gel electrophoresis. The detected band was consistent with the target gene product. The above bands were cut and the gel was cut according to the instructions. The product was purified according to the instructions of the DNA Extraction Mini Kit (Vazyme, Nanjing). Reaction primers (Table 3) and reaction system (Table 4) were used.

[0051] Table 3. LfiGAI1 amplification primers

[0052]

[0053] Table 4. LfiGAI1 amplification system

[0054]

[0055] 3.1.2 Primer design

[0056] PrimerPremier 5 was used to design specific primers for connecting the LfiGAI1 gene to the pSuper1300 (GFP) vector. The primer sequences are shown in Table 5.

[0057] Table 5. LfiGAI1 ligation into pSuper1300 (GFP) vector and vector primers

[0058]

[0059]

[0060] 3.1.3 Enzyme digestion

[0061] Double-digest pSuper-1300 (GFP) and the amplified and purified target gene product using the XbaI and KpnI restriction sites (Tables 6 and 7). Place the mixture in a PCR instrument at 37°C for 1 hour, perform gel electrophoresis, and then purify the product according to the method in 3.1.1.

[0062] Table 6. pSuper-1300 (GFP) vector enzyme digestion system

[0063] Components Addition amount QuickCutXbaI 1 μl QuickCutKpnI 1 μl carrier 6μl 10XQuickCutGreenBuffer 2 μl <![CDATA[ddH2O]]> 10 μl Total volume 20 μl

[0064] Table 7. LfiGAI1 target gene restriction enzyme digestion system

[0065] Components Addition amount QuickCutXbaI 1 μl QuickCutKpnI 1 μl DNA 3 μl 10XQuickCutGreenBuffer 2 μl ddH2O 13 μl Total volume 20 μl

[0066] 3.1.4 Connection

[0067] T4 DNA Ligase was used to ligate the target gene to the linearized vector after enzyme digestion, and the reaction system (Table 8) was set at 16°C for 5 h.

[0068] Table 8. Ligation reaction system

[0069]

[0070]

[0071] 3.1.5 Transformation into E. coli DH5a competent cells

[0072] (1) Take out the DH5a competent cell from the -80℃ freezer and thaw on ice;

[0073] (2) Add 10 μl of recombinant plasmid to the DH5a competent medium using a pipette;

[0074] (3) Place the competent cells on ice for 30 minutes, then in a 42°C water bath for 45 seconds;

[0075] (4) Add 700 μL of LB liquid medium without antibiotics;

[0076] (5) Place the transformed bacterial solution in a 37°C shaker at 200 rpm for 60 min.

[0077] (6) Centrifuge the bacterial solution at 5000 rpm for 1 min, retain 100 μl of the supernatant, resuspend it, and spread it on LB solid medium containing Kan and culture it upside down overnight.

[0078] 3.1.6 Bacterial liquid PCR and plasmid extraction

[0079] Single clones were picked and cultured in a shaker at 37°C with a speed of 200 rpm. The turbid strains were then identified by PCR. The strains corresponding to the positive bands were sent for sequencing and sequence comparison. The strains corresponding to the sequences consistent with the LfiGAI1 sequence were expanded overnight to extract the recombinant plasmids.

[0080] 3.1.7 Transformation into Agrobacterium GV3101 competent cells

[0081] (1) Take out the GV3101 competent cells from the -80°C freezer and thaw on ice;

[0082] (2) Transfer 1 μL of the above plasmid into the GV3101 competent cell;

[0083] (3) ice bath for 5 min, liquid nitrogen for 5 min, 37°C water bath for 5 min, ice bath for 5 min;

[0084] (4) Add 700 μL of LB liquid medium without antibiotics, place the transformed bacterial solution in a 28°C shaker at 200 rpm, and let it recover for 2-3 hours;

[0085] (5) Centrifuge at 6000 rpm for 1 min, retain 100 μL of the supernatant, resuspend, and apply to LB solid medium containing Kan+Rif, and invert and culture for 72 h;

[0086] (6) Pick a single colony for bacterial solution PCR, detect the amplified product by gel electrophoresis, and select the bacterial solution with the same size as the target band for bacterial preservation.

[0087] 3.2 Preparation of Nicotiana benthamiana

[0088] (1) In a sterilized clean bench, add 100 μL of sodium hypochlorite and 900 μL of Tween water to the EP tube containing tobacco seeds;

[0089] (2) Place in a shaker at 37°C, 200 rpm, and shake for 1 h;

[0090] (3) Add Tween water to the EP tube, shake it by hand, and wash it 5 times, each time for 2 minutes;

[0091] (4) Add ddH20 and blow the seeds onto filter paper. After absorbing the water, spread the seeds onto sterilized culture medium and seal.

[0092] (5) Cultivate seedlings under light at 25°C for about a week;

[0093] (6) Cover the seedlings with plastic wrap after transplanting. Remove the film after one week. Pay attention to watering and fertilizing. After about 3 weeks of cultivation, subsequent genetic transformation experiments can be carried out.

[0094] 3.3 Transient Expression in Nicotiana benthamiana

[0095] Agrobacterium containing the GFP-LfiGAI1 recombinant plasmid was shaken, the OD value was measured to 0.6-0.8, centrifuged at 5000 rpm for 8 minutes, resuspended in infection solution, and the OD value was measured to 0.6-0.8. It was allowed to stand for 2-3 hours. Three-week-old Nicotiana benthamiana was genetically transformed and injected into the lower epidermis of the tobacco with a sterile syringe. The treatment was dark for 1 day and light for 2 days.

[0096] 3.4 Laser confocal microscopy observation

[0097] Place a drop of water in the center of a glass slide. Tear off the lower epidermis of tobacco and spread it in the water. Add 10 μg / mL of DAPI stain. Rinse with distilled water, then place a coverslip on one side. Remove excess water with filter paper to create a temporary slide. Observe the slide using a specific excitation wavelength.

[0098] 4 Results and Analysis

[0099] 4.1 Cloning and analysis of LfiGAI1

[0100] The Lagerstroemia genome was blasted against the model plant Arabidopsis thaliana, and the sequence of Lagerstroemia LfiGAI1 was obtained. Specific amplification primers were designed, and the Lagerstroemia stem cDNA was used as a template to clone the LfiGAI1 gene, which is 1752 bp in length ( Figure 1 ).

[0101] We found GAIs of different species in NCBI, performed multiple sequence alignments with LfiGAI1, and constructed a phylogenetic tree ( Figure 2 ), PoSTYK and SsSTYK clustered together, showing high homology. NCBI BLASTP analysis of the conserved domains of LfiGAI1 revealed that LfiGAI1 possesses a della conserved domain, indicating that it belongs to the GRAS family.

[0102] 4.2 Spatial and temporal expression analysis of LfiGAI1 in Lagerstroemia

[0103] The expression levels of LfiGAI1 gene in the stem tip, tender stem and mature stem of tall and dwarf crape myrtle were detected by real-time fluorescence quantitative PCR. The results showed that the expression levels of LfiGAI1 gene in the three tissues of dwarf crape myrtle were significantly higher than those in tall crape myrtle ( Figure 3 ).

[0104] 4.3 Subcellular localization

[0105] Bacterial liquid PCR results ( Figure 4 ) showed that the overexpression vector was constructed successfully. The PCR results of the bacterial solution after the correctly sequenced 1300 empty vector and the constructed LfiGAI1 overexpression vector were transformed into Agrobacterium GV3101 ( Figure 5) showed that the 1300 empty vector and the constructed LfiGAI1 overexpression vector were successfully transformed into Agrobacterium GV3101. DAPI is a blue fluorescent dye that can penetrate the cell membrane. After binding to double-stranded DNA, it can produce fluorescence that is more than 20 times stronger than DAPI itself. DAPI is commonly used for general cell nucleus staining and double-stranded DNA staining in certain specific cases. The maximum excitation wavelength of DAPI is 340nm, and the maximum emission wavelength is 488nm; after DAPI binds to double-stranded DNA, the maximum excitation wavelength is 364nm, and the maximum emission wavelength is 454nm. Subcellular localization results ( Figure 6 ) showed that the LfiGAI1 gene was expressed in both the nucleus and the cell membrane.

[0106] Example 2

[0107] 1. Functional identification of LfiGAI1 transgenic tobacco

[0108] 1.1 Test materials

[0109] Large-leaf tobacco (Nicotiana tabacum).

[0110] 2. Leaf Disc Method for Tobacco Transformation

[0111] 2.1 Preparation of infection solution

[0112] The bacterial solution obtained in 3.1.7 of Example 1 was expanded to 50 ml of liquid LB medium supplemented with Kan and Rif antibiotics at a ratio of 1:50, and cultured on a 28°C constant temperature shaker at 200 rpm for about 6 h until the OD600 of the bacterial solution reached 0.4-0.6. In a clean bench, the bacterial solution that met the target OD value was transferred to a 50 ml sterile centrifuge tube and centrifuged at 5000 rpm for 10 min to fully collect the bacteria, and the supernatant was discarded; according to the OD600 value of the bacterial solution, the bacteria were resuspended in an appropriate volume of 1 / 2 MS liquid medium so that the OD600 of the infection solution was around 0.4, which was used for explant infection and transformation; 1 / 2 MS liquid medium: 1 / 2 MS powder 2.2 g / L + sucrose 25 g / L.

[0113] 2.2 Agrobacterium transformation of explants

[0114] Select healthy and strong tobacco sterile seedlings, cut healthy leaves of basically the same size and color on filter paper in a clean workbench, carefully cut off the leaf edge, cut along both sides of the main vein, and cut into 1cmx1cm leaf discs, carefully clamp them on the pre-culture medium with tweezers, flatten them, and pre-culture for 2d; pre-culture medium: MS powder 4.43g / L + sucrose 25g / L + agar 7g / L; the pre-cultured leaf discs were clamped into the prepared pSuper1300::GFP bacterial solution and pSuper1300::LfiGAI1::GFP bacterial solution, respectively, and infected for 10-15min, during which they were gently rotated and shaken to ensure that each leaf disc was fully in contact with Agrobacterium; take out the leaves, place them on sterile filter paper, absorb the excess bacterial solution, clamp the leaf disc on the co-culture medium, and carefully press with the flat end of the tweezers to ensure that the cut is in full contact with the culture medium, and culture under dark conditions in the tissue culture room. Co-cultivation for 2 days; co-cultivation medium: MS powder 4.43g / L + 6-BA 0.5mg / L + NAA 0.05mg / L + sucrose 25g / L + agar 7g / L; soak the leaf disc after co-cultivation in 300mg / L timentin solution for 10min, then gently shake and wash with sterile water 3 times, each time for 2min, then place the washed leaves on sterile filter paper to absorb excess water. If there is no Agrobacterium growth in the leaf disc after co-cultivation, the washing step can be omitted; transfer the leaf disc to the screening medium containing antibiotics and culture it at a temperature of 28°C and a photoperiod of 16h light / 8h dark conditions; screening medium: MS powder 4.43g / L + 6-BA 1mg / L + NAA 0.1mg / L + sucrose 25g / L + agar 7g / L, sterilize and cool, then add 200mg / L timentin and 50mg / L hygromycin for screening. The culture medium was replaced every 10 days to obtain resistant seedlings. When resistant seedlings grew to over 1 cm in length, they were cut and transferred to rooting screening medium. Rooting medium consisted of 4.43 g / L MS powder, 25 g / L sucrose, and 7 g / L agar. After sterilization and cooling, 200 mg / L timentin and 50 mg / L hygromycin were added. After the transgenic seedlings had established roots, they were removed, the root culture medium was washed, and the seedlings were potted and placed in an artificial climate chamber for maintenance.

[0115] 2.3 Identification of resistant seedlings and RT-PCR detection of exogenous genes

[0116] 2.3.1 Identification of resistant seedlings

[0117] (1) DNA extraction from tobacco leaves

[0118] Resistant tobacco plants infected with pSuper1300::GFP were used as controls. Resistant tobacco leaves (control and T1 generation) were collected, wrapped, placed in liquid nitrogen, and stored in a −80°C freezer. DNA from all samples was extracted according to the instructions of the Plant DNA Extraction Kit (Tiangen, Beijing).

[0119] (2) PCR detection of exogenous genes in tobacco DNA

[0120] PCR amplification was performed using the specific primers designed in Table 3 of Example 1 with DNA from resistant tobacco leaves (control and T1 generation) as templates. The PCR reaction system is shown in Table 9. The program was as follows: pre-denaturation at 95°C for 2 minutes, denaturation at 95°C for 10 seconds, annealing at 58°C for 30 seconds, extension at 72°C for 1 minute, and 35 cycles. PCR products were detected by gel electrophoresis. PCR results ( Figure 7 ) showed that the transgenic tobacco was successfully transformed.

[0121] Table 9 PCR reaction system

[0122]

[0123]

[0124] 2.3.2 Detection of exogenous gene expression in transgenic tobacco

[0125] (1) RNA extraction and cDNA synthesis from tobacco leaves

[0126] Tobacco leaves from transgenic and control lines were collected, wrapped in tin foil, and stored at -80°C. RNA extraction and detection from tobacco leaves were performed using the RNAsimple Total RNA Kit (TIANGEN). cDNA was synthesized using the HiScript IIQ RT SuperMix for qPCR (+gDNAwiper) (vazyme) premixed reverse transcription kit instructions, using a two-step process to remove genomic DNA and perform reverse transcription to generate cDNA.

[0127] (2) Fluorescence quantitative PCR was performed using cDNA of transgenic and control strains as templates. The tobacco fluorescence quantitative internal reference gene was NbTubulin (ID: 104112550) (Wang et al., 2014). The specific primers for LfiGAI1 and Nicotiana tabacum internal reference fluorescence quantitative are shown in Table 10. The fluorescence quantitative PCR reaction program was as follows: pre-denaturation at 95°C for 30 s, 40 cycles of 95°C for 10 s and 60°C for 30 s. The melting curve was 65°C-95°C, with an increase of 0.5°C every 5 s. Fluorescence quantitative PCR results ( Figure 8 ) showed that the LfiGAI1 gene in the transgenic tobacco line had been successfully overexpressed.

[0128] Table 10 Specific primers for transgenic tobacco qRT-PCR

[0129]

[0130] 2.3.3 Phenotypic and anatomical observation of transgenic tobacco

[0131] (1) Phenotypic determination

[0132] Three positive strains with high LfiGAI1 expression levels were selected, and three tobacco strains with no transfection were used as controls for phenotypic observation. Transgenic tobacco and control tobacco with consistent growth potential in the seed-screening culture dishes were selected and transplanted into culture soil. After potting and flowering, phenotypic traits such as plant height, number of internodes, average internode length, stem diameter, fruit set, fruit length, fruit width, leaf length, and leaf width of the transgenic and control tobacco plants were measured. Results ( Figure 9 and Figure 10 ) showed that compared with the control strain, the overexpression strain had significant differences in phenotypes such as plant height, average internode length, stem diameter, fruit length, fruit width, leaf length, and leaf width, and was obviously inhibited.

[0133] (2) Anatomical observation

[0134] The transgenic tobacco and control tobacco stem segments were sampled from the same part. Paraffin sectioning was used to observe the transverse and longitudinal sections of the transgenic tobacco and control tobacco stem segments ( Figure 11 ), and statistical analysis was performed on the length and width of stem segment cells.

[0135] (3) SPSS 20.0 (Chicago, USA) was used to perform multiple comparative analyses on the phenotypic and anatomical data. Figure 12 ), the results showed that the overexpressing transgenic lines were significantly shorter than the control lines in terms of transverse xylem cell width, transverse pith cell width, longitudinal xylem cell length, longitudinal xylem cell width, longitudinal pith cell length, and longitudinal pith cell width.

[0136] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A Lagerstroemia plant height regulating gene, characterized in that: The nucleotide sequence of the crape myrtle plant height regulating gene is shown in SEQ ID NO.

1.

2. The primer set for amplifying the crape myrtle plant height regulating gene according to claim 1, characterized in that: It includes an upstream primer as shown in SEQ ID NO.6 and a downstream primer as shown in SEQ ID NO.

7.

3. A gene overexpression recombinant vector, characterized in that: The gene overexpression recombinant vector targets the crape myrtle plant height regulating gene according to claim 1 or contains the crape myrtle plant height regulating gene according to claim 1.

4. A gene knockdown recombinant vector, characterized in that: The gene knockdown recombinant vector targets the crape myrtle plant height regulating gene according to claim 1.

5. A gene-regulated engineered bacterium, characterized in that: Contains the gene overexpression recombinant vector according to claim 3 or the gene knockdown recombinant vector according to claim 4.

6. A kit for regulating plant height, characterized in that: The kit contains the gene overexpression recombinant vector according to claim 3, the gene knockdown recombinant vector according to claim 4, or the gene regulation engineering bacteria according to claim 5.

7. Use of the crape myrtle plant height regulating gene according to claim 1, the primer set according to claim 2, the gene overexpression recombinant vector according to claim 3, the gene knockdown recombinant vector according to claim 4, or the gene regulation engineering bacteria according to claim 5 in preparing a plant height regulating product.

8. The use according to claim 7, characterized in that The plants include crape myrtle and tobacco.

9. A genetically engineered plant, characterized in that: The plant contains the overexpressed crape myrtle plant height regulating gene according to claim 1.

10. A genetically engineered plant, characterized in that: The genome of the plant contains the crape myrtle plant height regulating gene according to claim 1, and the expression of the crape myrtle plant height regulating gene is suppressed.

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