The LfiGAI1 gene of Lagerstroemia indica and its application in regulating plant height

Abstract

This invention provides the LfiGAI1 gene of Crape Myrtle and its application in regulating plant height, belonging to the field of molecular biotechnology. The LfiGAI1 gene can inhibit the division and elongation of Crape Myrtle cells, thereby regulating plant height. Overexpression of this gene in tobacco can shorten the internode length of overexpressing lines and significantly reduce plant height, indicating that GAI1 can inhibit Crape Myrtle cell elongation and thus regulate plant height, which is of great significance for the breeding of plant varieties with specific plant heights.

Description

Technical Field

[0001] This invention relates to the field of molecular biology, and in particular to the Lagerstroemia indica LfiGAI1 gene and its application in regulating plant growth and development. Background Technology

[0002] Crape myrtle (Lagerstroemia indica L.) is a deciduous small tree or shrub belonging to the genus Lagerstroemia in the family Lythraceae, widely distributed in Asia, America, and Oceania. It typically grows to a height of 2-7 meters, with smooth, clean bark, a often twisted trunk, and quadrangular young branches. The leaves are elliptical or obovate, and papery. The flowers are borne in terminal panicles, displaying a rich variety of colors including purple, red, pink, and white. The petals are wrinkled, and the flowering period lasts 3-4 months, from summer to autumn, hence the name "Hundred Days Red." Crape myrtle is highly adaptable, preferring sunny, well-drained environments. It is drought-tolerant, cold-hardy, and not particular about soil type, growing well in both calcareous and acidic soils. Therefore, it holds an important place in landscaping, garden design, and bonsai art. Furthermore, the leaves and branches of crape myrtle have a significant ability to trap particulate matter in the air, offering outstanding ecological benefits and making it an excellent tree species with both ornamental value and environmental protection functions.

[0003] Plant height is one of the key traits affecting the landscaping application and ornamental value of crape myrtle. In landscape design, different scenarios require different plant shapes for crape myrtle. For example, when used as a street tree or large green plant, a taller shape is needed to create a visual focal point, while as a garden bonsai or small landscape, dwarf varieties are required to fit the spatial scale. Traditionally, plant height control relies heavily on horticultural pruning, but manual pruning is time-consuming, labor-intensive, and has limited effectiveness, making it difficult to precisely control plant proportions and potentially harming plant health due to over-pruning. Controlling plant height through genetic means can fundamentally optimize the natural growth characteristics of crape myrtle, cultivating varieties that adapt to diverse needs. For example, low-growing, compact varieties can reduce maintenance costs and extend their ornamental lifespan, while tall, upright varieties can enhance their ecological barrier function. Furthermore, reasonable plant height management helps improve the efficiency of crape myrtle's vertical space utilization, enhances its landscape harmony with other plants, and promotes photosynthetic efficiency and stress resistance, providing more possibilities for urban greening, ecological restoration, and the development of the specialty seedling industry. Summary of the Invention

[0004] The purpose of this 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 heights.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a gene for regulating the height of crape myrtle plants, the nucleotide sequence of which is shown in SEQ ID NO.1.

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

[0008] This invention provides a gene overexpression recombinant vector that targets or contains the above-mentioned Lagerstroemia indica height-regulating gene.

[0009] This invention provides a gene knockdown recombinant vector that targets the above-mentioned Lagerstroemia indica plant height regulating gene.

[0010] This invention provides a gene-regulated engineered bacterium containing the above-mentioned gene overexpression recombinant vector or gene knockdown recombinant vector.

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

[0012] This invention provides the application of the above-mentioned Lagerstroemia indica plant height regulating gene, primer set, gene overexpression recombinant vector, gene knockdown recombinant vector or gene regulating engineered bacteria in the preparation of plant height regulating products.

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

[0014] The present invention provides a genetically engineered plant containing the above-mentioned highly regulatory gene of Lagerstroemia indica that has been overexpressed.

[0015] The present invention provides a genetically engineered plant whose genome contains the above-mentioned highly regulatory gene of Lagerstroemia indica, and the expression of the highly regulatory gene of Lagerstroemia indica is suppressed.

[0016] The beneficial effects of this invention are:

[0017] This invention provides the gene LfiGAI1, which can inhibit the division and elongation of crape myrtle cells and thus regulate the height growth of crape myrtle plants. Overexpression of this gene in tobacco can shorten the internode length of overexpressing lines and significantly reduce plant height, indicating that GAI1 can inhibit the elongation of crape myrtle cells and thus regulate the height of crape myrtle plants, which is of great significance for the breeding of plant varieties with specific plant height. Attached Figure Description

[0018] Figure 1 Gel electrophoresis image of LfiGAI1 gene clone; M: DL 2000 Marker;

[0019] Figure 2 A phylogenetic tree diagram;

[0020] Figure 3 This is a diagram showing the expression pattern of the LfiGAI1 gene in different tissues of tall and dwarf crape myrtle; S_SAM: shoot tip of tall crape myrtle; D_SAM: shoot tip of dwarf crape myrtle; S_TS: young stem of tall crape myrtle; D_TS: young stem of dwarf crape myrtle; S_MS: mature stem of tall crape myrtle; D_MS: mature stem of dwarf crape myrtle. The data in the graph are the mean ± standard deviation of three biological studies. * indicates significant difference (one-way ANOVA was used, *: p < 0.05, **: p < 0.01, ***: p < 0.001).

[0021] Figure 4 Gel electrophoresis image of the overexpression vector construction results; M: DL2000 Marker;

[0022] Figure 5 Gel electrophoresis images of Agrobacterium GV3101 overexpression vector; M: DL2000 Marker; 1-5 are 1300 empty vectors, 6-15 are LfiGAI1 overexpression vectors;

[0023] Figure 6 Subcellular localization map of LfiGAI1::GFP; DAPI: DAPI staining; GFP: excitation fluorescence; Bright: results observed under bright field; Merge: composite results of DAPI, GFP and bright field overlays;

[0024] Figure 7 Figure 1 shows the screening results of 1300 empty transgenic tobacco and LfiGAI1 transgenic large-leaf tobacco; A: DNA identification of Superpromoter::GFP transgenic tobacco; B: DNA identification of Superpromoter::LfiGAI1::GFP transgenic tobacco; M: DL2000 Marker;

[0025] Figure 8 Real-time fluorescence quantitative quantification results of LfiGAI1 gene expression in 1300 empty transgenic tobacco and LfiGAI1 transgenic large-leaf tobacco;

[0026] Figure 9 Figure showing the plant height variation of LfiGAI1 transgenic large-leaf tobacco;

[0027] Figure 10 Statistical graphs showing the phenotypic traits related to plant height in 1300 empty transgenic tobacco plants and LfiGAI1 transgenic large-leaf tobacco plants; data are the mean ± standard deviation of three biological studies, *, ** represent significant differences (one-way ANOVA was used, *: p < 0.05, **: p < 0.01);

[0028] Figure 11Paraffin sections of stem segments from 1300 empty transgenic tobacco and LfiGAI1 transgenic large-leaf tobacco.

[0029] Figure 12 Statistical analysis of pith and xylem cell sizes in cross-sections and longitudinal sections of stem segments from 1300 empty transgenic tobacco plants and LfiGAI1 transgenic large-leaf tobacco plants; data are the mean ± standard deviation of three biological studies, *, ** represent significant differences (one-way ANOVA was used, *: p < 0.05, **: p < 0.01). Detailed Implementation

[0030] The technical solutions provided by the present invention will be 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 examples is shown in SEQ ID NO.1:

[0032]

[0033] Example 1

[0034] 1.1 RNA extraction from crape myrtle stem tips, young stems, and mature stems

[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 dwarf Lagerstroemia indica D043 segregating populations were used as materials, and total RNA was extracted from each part using the RNAsimple Total RNA Kit (TIANGEN).

[0036] 1.2 cDNA Synthesis

[0037] Following 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 to obtain cDNA from various parts of the tall and dwarf crape myrtle.

[0038] 2. Expression pattern of the LfiGAI1 gene

[0039] 2.1 qRT-PCR primer design

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

[0041] Table 1. Primers for Real-Time Gene Quantification

[0042]

[0043] 2.2 qRT-PCR reaction

[0044] According to the ChamQ Universal SYBR qPCR Master Mix universal high-sensitivity dye-based quantitative PCR detection kit, a 15 μL qRT-PCR reaction system was prepared (Table 2), and three technical replicates were set up. The reaction was performed on an AppliedBiosystems Quantitative Study... TM 5. The real-time PCR system was completed using 2 -△△CT The method analyzes the data.

[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 the target gene

[0050] Using cDNA from the tender stems of both tall and dwarf crape myrtle plants as templates, the open reading frame of LfiGAI1 was amplified using 2×KeyPo SE Master Mix (DyePlus). The amplification reaction was performed according to the reagent instructions, and the amplified products were detected by gel electrophoresis. The detected bands were consistent in size with the target gene product. The bands were then cut into gels and analyzed according to... The DNA Extraction Mini Kit (Vazyme, Nanjing) was used to purify the product according to the instructions. Reaction primers (Table 3), reaction system (Table 4).

[0051] Table 3. LfiGAI1 amplification primers

[0052]

[0053] Table 4. LfiGAI1 amplification system

[0054]

[0055] 3.1.2 Primer Design

[0056] Specific primers for ligating the LfiGAI1 gene to the pSuper1300 (GFP) vector were designed using PrimerPremier 5. 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] pSuper-1300 (GFP) and the target gene product amplified and purified above were double-digested using Xbal and KpnI restriction sites (Tables 6 and 7). The mixture was placed in a PCR instrument at 37°C for 1 hour and then detected by gel electrophoresis. The product was then purified according to the method in 3.1.1.

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

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

[0064] Table 7. Enzyme digestion system for LfiGAI1 target gene

[0065] Components Added amount QuickCutXbaI 1μl QuickCutKpnI 1μl DNA 3μl 10X QuickCutGreenBuffer 2μl ddH2O 13μl Total volume 20μl

[0066] 3.1.4 Connection

[0067] The target gene was ligated to the linearized vector digested with T4 DNA Ligase, and the reaction system is shown in Table 8. The reaction conditions were 16°C for 5 hours.

[0068] Table 8. Connection Reaction System

[0069]

[0070]

[0071] 3.1.5 Transformation into Escherichia coli DH5α competent cells

[0072] (1) Take the DH5a competent states out of the -80℃ freezer and place them on ice to thaw;

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

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

[0075] (4) Add 700 μL of antibiotic-free LB liquid medium;

[0076] (5) Place the transformed bacterial culture in a 37℃ shaker and set the speed to 200 rpm for 60 min to recover;

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

[0078] 3.1.6 Bacterial culture PCR and plasmid extraction

[0079] Single clones were selected and cultured in a shaker at 37°C with a rotation speed of 200 rpm. The turbid strains were then identified by PCR. The strains corresponding to the positive bands were sent for sequencing to compare the sequences. The strains corresponding to the sequences that matched the LfiGAI1 sequence were cultured overnight and the recombinant plasmids were extracted.

[0080] 3.1.7 Transformation into Agrobacterium GV3101 competent cells

[0081] (1) Remove the GV3101 competent state from the -80℃ freezer and place it on ice to thaw;

[0082] (2) Take 1 μL of the above plasmid and transfer it to GV3101 competent cells;

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

[0084] (4) Add 700uL of antibiotic-free LB liquid medium, place the transformed bacterial culture in a 28℃ shaker, set the speed to 200rpm, and revive for 2-3h;

[0085] (5) Centrifuge at 6000 rpm for 1 min, resuspend in 100 μL of supernatant, spread onto LB solid medium containing Kan+Rif, and incubate upside down for 72 h.

[0086] (6) Select a single colony for bacterial PCR, perform gel electrophoresis on the amplification product, and select a bacterial solution with the same size as the target band for preservation.

[0087] 3.2 Preparation of Benzoic tobacco

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

[0089] (2) Place in a shaker at 37℃ and shake at 200 rpm for 1 hour;

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

[0091] (4) Add ddH2O and blow the seeds onto filter paper. After absorbing the moisture, sprinkle the seeds onto sterilized culture medium and seal.

[0092] (5) Seedlings were obtained after about one week of cultivation under light at 25℃;

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

[0094] 3.3 Transient expression of *Tobacco Benzovia*

[0095] Agrobacterium containing the GFP-LfiGAI1 recombinant plasmid was shaken vigorously, and the OD value was measured to 0.6-0.8. After centrifugation at 5000 rpm for 8 min, the cells were resuspended in the infection solution, and the OD value was measured to 0.6-0.8. After standing for 2-3 h, the cells were genetically transformed into three-week-old Nicotiana benthamiana. The lower epidermis of the tobacco was injected with a sterile syringe, and the cells were treated in the dark for 1 day and in the light for 2 days.

[0096] 3.4 Observation using laser confocal microscopy

[0097] Place a drop of water in the center of a glass slide, tear off the lower epidermis of a tobacco leaf and spread it in the water, then add 10 μg / mL DAPI stain to stain it. Rinse with distilled water, then cover with a coverslip from one side and use filter paper to absorb excess water from one side to prepare 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 genome of *Lagerstroemia indica* was BLASTed with that of the model plant *Arabidopsis thaliana*, and the sequence of *LfiGAI1* was obtained. Specific amplification primers were designed, and the *LfiGAI1* gene, 1752 bp in length, was cloned using *Lagerstroemia indica* young stem cDNA as a template. Figure 1 ).

[0101] GAIs from different species were found in NCBI, and multiple sequence alignments were performed with LfiGAI1 to construct a phylogenetic tree. Figure 2 PoSTYK and SsSTYK cluster together, showing high homology. Conserved domain analysis of the LfiGAI1 protein using BLASTP in NCBI revealed that LfiGAI1 possesses the della conserved domain, classifying it as a member of the GRAS family.

[0102] 4.2 Spatiotemporal Expression Analysis of LfiGAI1 in Crape Myrtle

[0103] The expression levels of the LfiGAI1 gene in the shoot tips, young stems, and mature stems of both tall and dwarf crape myrtle were detected using real-time quantitative PCR. The results showed that the expression level of the LfiGAI1 gene in all three tissues of dwarf crape myrtle was significantly higher than that in tall crape myrtle. Figure 3 ).

[0104] 4.3 Subcellular localization

[0105] Bacterial PCR results ( Figure 4 This indicates that the overexpression vector was successfully constructed. PCR was performed on the bacterial culture of Agrobacterium GV3101 after the correctly sequenced empty vector and the constructed LfiGAI1 overexpression vector were transformed into the vector. Figure 5This indicates 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 cell membranes. After binding to double-stranded DNA, it can produce fluorescence more than 20 times stronger than DAPI itself. DAPI is commonly used for routine nuclear staining and double-stranded DNA staining under certain specific conditions. The maximum excitation wavelength of DAPI is 340 nm, and the maximum emission wavelength is 488 nm; after DAPI binds to double-stranded DNA, the maximum excitation wavelength is 364 nm, and the maximum emission wavelength is 454 nm. Subcellular localization results ( Figure 6 This indicates that the LfiGAI1 gene is expressed in both the cell nucleus and cell membrane.

[0106] Example 2

[0107] 1. Functional identification of LfiGAI1 transgenic tobacco

[0108] 1.1 Test Materials

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

[0110] 2. Leaf disc method for tobacco conversion

[0111] 2.1 Preparation of Infection Solution

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

[0113] 2.2 Agrobacterium-mediated transformation of explants

[0114] Select robust, sterile tobacco seedlings. In a clean bench, cut healthy leaves of similar size and color onto filter paper. Carefully trim the leaf margins and cut along both sides of the midrib to create 1cm x 1cm leaf discs. Carefully place these discs onto a pre-culture medium, flatten them, and pre-culture for 2 days. The pre-culture medium consists of 4.43 g / L MS powder, 25 g / L sucrose, and 7 g / L agar. Place the pre-cultured leaf discs into prepared pSuper1300::GFP and pSuper1300::LfiGAI1::GFP bacterial solutions, respectively, and incubate for 10-15 minutes, gently rotating and shaking to ensure full contact between each leaf disc and Agrobacterium. Remove the leaves, place them on sterile filter paper, blot off excess bacterial solution, and place the leaf discs onto a co-culture medium. Carefully press the cut surfaces with tweezers to ensure full contact between the cut surfaces and the medium. Incubate in the dark in a tissue culture room. Co-culture for 2 days; Co-culture medium: MS powder 4.43 g / L + 6-BA 0.5 mg / L + NAA 0.05 mg / L + sucrose 25 g / L + agar 7 g / L; After co-culture, the leaf discs were soaked in 300 mg / L termethin solution for 10 min, then gently shaken and rinsed 3 times with sterile water for 2 min each time. After that, the rinsed leaves were placed on sterile filter paper to absorb excess water. If no Agrobacterium growth was observed in the leaf discs after co-culture, the rinsing step can be omitted; The leaf discs were transferred to a selection medium containing antibiotics and cultured at 28℃ under a photoperiod of 16 h light / 8 h dark; Selection medium: MS powder 4.43 g / L + 6-BA 1 mg / L + NAA 0.1 mg / L + sucrose 25 g / L + agar 7 g / L, sterilized and cooled, then 200 mg / L termethin and 50 mg / L hygromycin were added for selection. The culture medium was changed every 10 days to obtain resistant seedlings. When the resistant seedlings grew to more than 1 cm in length, they were cut off and transferred to rooting selection medium. The rooting medium consisted of MS powder 4.43 g / L + sucrose 25 g / L + agar 7 g / L. After sterilization and cooling, 200 mg / L termethin and 50 mg / L hygromycin were added. After the transgenic seedlings rooted, they were removed, the culture medium was washed off the roots, and they were potted and placed in an artificial climate chamber for maintenance and management.

[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 bacterial suspension were used as controls. Resistant tobacco leaves (control and T1 generation) were collected, wrapped, placed in liquid nitrogen, and stored at -80℃. DNA was extracted from all samples according to the instructions of the plant DNA extraction kit (Tiangen, Beijing).

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

[0120] Using the specific primers designed in Table 3 of Example 1, PCR amplification was performed using DNA from resistant tobacco leaves (control and T1 generation) as templates. The PCR reaction system is shown in Table 9, and the program was: 95℃ pre-denaturation for 2 min, 95℃ denaturation for 10 s, 58℃ annealing for 30 s, 72℃ extension for 1 min, and 35 cycles. The PCR products were then detected by gel electrophoresis. PCR results ( Figure 7 This indicates that the genetically modified tobacco conversion was successful.

[0121] Table 9 PCR Reaction System

[0122]

[0123]

[0124] 2.3.2 Detection of exogenous gene expression levels 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 aluminum foil, and stored at -80°C. Total RNA was extracted from tobacco leaves using the RNAsimple Total RNA Kit (TIANGEN). cDNA synthesis was performed according to the instructions of the HiScript IIQ RT SuperMix for qPCR (+gDNAwiper) (vazyme) reverse transcription premix kit, following a two-step process: removal of genomic DNA and reverse transcription.

[0127] (2) Quantitative real-time PCR was performed using cDNA from transgenic and control lines as templates. The tobacco quantitative real-time reference gene was NbTubulin (ID: 104112550) (Wang et al., 2014). Specific primers for LfiGAI1 and the large-leaf tobacco quantitative real-time reference gene are shown in Table 10. The quantitative real-time PCR reaction program was: 95℃ pre-denaturation for 30s, 95℃, 10s, and 60℃, 30s cycles for 40 cycles; melting curve was performed at 65℃-95℃, increasing by 0.5℃ every 5s. Quantitative real-time PCR results ( Figure 8 This indicates that the LfiGAI1 gene has been successfully overexpressed in the transgenic tobacco lines.

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

[0129]

[0130] 2.3.3 Phenotypic and anatomical observations of transgenic tobacco

[0131] (1) Phenotypic determination

[0132] Three positive lines with high LfiGAI1 expression were selected, and three tobacco lines transgenic into empty vectors were used as controls for phenotypic observation. Transgenic tobacco plants with consistent growth vigor from the screening culture dishes and control tobacco plants were transplanted into culture soil and potted until flowering. Phenotypic traits such as plant height, number of internodes, average internode length, stem diameter, fruit yield, fruit length, fruit width, leaf length, and leaf width were measured in both transgenic and control tobacco plants. Results ( Figure 9 and Figure 10 The results showed that, compared with the control strain, the overexpression strain exhibited significant differences in phenotypic characteristics such as plant height, average internode length, stem diameter, fruit length, fruit width, leaf length, and leaf width, indicating that it was significantly inhibited.

[0133] (2) Anatomical observation

[0134] Stem segments from the same locations in both transgenic and control tobacco plants were collected. Paraffin sectioning was used to observe the cross-sections and longitudinal sections of the stem segments from both plants. Figure 11 ), and perform statistical analysis on the length and width of stem segment cells.

[0135] (3) Multiple comparison analyses were performed on the phenotypic and anatomical data using SPSS 20.0 (Chicago, USA). Figure 12 The results showed that, compared with the control line, the overexpressing transgenic line was significantly shorter in terms of xylem cell width, pith cell width, xylem cell length, xylem cell width, pith cell length, and pith cell width in cross sections.

[0136] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

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

1.

2. The primer set for amplifying the Lagerstroemia indica plant height regulating gene as described in claim 1, characterized in that, This includes the upstream primer shown in SEQ ID NO. 6 and the downstream primer shown in SEQ ID NO.

7.

3. A gene overexpression recombinant vector, characterized in that, The gene overexpression recombinant vector contains the Lagerstroemia indica plant height regulating gene as described in claim 1.

4. A gene-regulated engineered bacterium, characterized in that, Contains the gene overexpression recombinant vector as described in claim 3.

5. A plant height regulation kit, characterized in that, The kit contains the gene overexpression recombinant vector of claim 3 or the gene-regulated engineered bacteria of claim 4.

6. The application of the crape myrtle height-regulating gene of claim 1, the gene overexpression recombinant vector of claim 3, or the gene-regulating engineered bacteria of claim 4 in regulating plant height, characterized in that, Plant height is regulated by overexpressing the Lagerstroemia indica height-regulating gene as described in claim 1 to shorten the plant height. The plants mentioned include crape myrtle and tobacco.

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