Application of overexpression of Populus tomentosa strigolactone receptor PtoD14 gene in increasing wood yield

Abstract

The invention discloses an application of overexpressing a strigolactone receptor PtoD14 gene of Populus tomentosa in improving wood yield. The Populus tomentosa strigolactone receptor PtoD14 gene is cloned from a wild-type Populus tomentosa, and the PtoD14 gene is introduced into a Populus tomentosa plant by a genetic engineering method, so as to obtain a Populus tomentosa strain with enhanced secondary development. The number of secondary xylem cell layers in a 3-month-old PtoD14 gene-transformed Populus tomentosa is 8-21 more than that in a 3-month-old non-transformed common Populus tomentosa. The invention is of great significance for providing high wood yield for large-scale production of Populus tomentosa.

Description

Technical Field

[0001] The invention relates to the field of biotechnology, and in particular to application of overexpressing a Populus tomentosa strigolactone receptor PtoD14 gene in improving wood yield. Background Art

[0002] Wood is one of the most abundant renewable resources in the world and is a natural, environmentally friendly and low-energy material. The formation of wood is a complex developmental process, which is divided into two stages: primary growth and secondary growth. In the primary growth stage of woody plants, stem cells in the apical meristem continuously produce new cells, supporting the upward growth of plants while producing organs such as lateral branches and leaves (Aichinger et al., 2012; Miyashima et al., 2013; Ohashi-Ito and Fukuda, 2010; Weigel and Jurgens, 2002). In the secondary growth stage, plants use the continuous division of secondary xylem and secondary phloem generated by the cambium to the inner and outer sides to carry out secondary growth perpendicular to the primary growth, so that the plants grow horizontally and the stems become thicker (Chao et al., 2018). Secondary growth is the biological basis for the formation of wood in perennial woody plants. The development mechanism of secondary xylem is not only the theoretical basis for increasing wood yield and improving wood quality, but also an ideal model for analyzing the coordinated regulation of genetic and environmental factors. However, traditional forest tree breeding has many difficulties, such as long cycle and difficult breeding. Therefore, using genetic engineering technology to create new forest tree germplasm with highly developed vascular tissue has broad development prospects.

[0003] Poplar (Populus spp.) is one of the fastest-growing timber species with the largest cultivation area in the world's mid-latitude plains. It has the characteristics of fast growth, high yield and easy renewal. It is widely used and planted in timber, papermaking, and windbreak and sand fixation. In addition, poplars have deep roots and luxuriant branches, can prevent wind and sand fixation, and reduce soil erosion. They are ideal tree species for building forests and urban and rural greening (Shi Gongming et al., 2009). In addition to its important ecological value, poplars also have a wide range of industrial and construction uses. Poplars can be used for pulping and papermaking, are the raw materials for fiberboard and plywood, are also used as materials for construction and furniture, and are also important raw materials for the bioenergy industry (Wu Dingxin et al., 1997; Fu Feng et al., 1999; Huang Bei et al., 2013).

[0004] Populus tomentosa is a native tree species unique to my country. It has become a widely planted timber species in northern China due to its rapid growth, excellent wood quality and strong adaptability. In recent years, the establishment of genetic transformation system and gene knockout technology of Populus tomentosa has made it possible to conduct in-depth research on the regulatory mechanism of important traits such as wood formation and environmental adaptation (Fan et al. 2015; Xu et al. 2017). With the in-depth study and analysis of the regulatory mechanism of secondary development of poplar, it is of great scientific significance and economic value to create excellent tree species that promote secondary development of poplar through genetic engineering technology and thus increase timber yield.

[0005] Plant hormones strigolactones (SLs) have been reported to have a positive regulatory effect on cambium activity (Agusti et al., 2011). As a key regulator of plant growth and development, DWARF14 (D14) acts downstream of strigolactone synthesis, acting as a component of hormone signaling or an enzyme that converts strigolactones into biologically active forms. In Arabidopsis, AtD14 can regulate hypocotyl growth by mediating the hydrolysis of GR24 (Yao R et al., 2016). These studies indicate that D14 plays an important role in regulating secondary development in woody plants, but its mechanism is still unclear. Summary of the invention

[0006] In view of this, one of the objects of the present invention is to provide an application of overexpressing the Populus tomentosa strigolactone receptor PtoD14 gene in increasing wood yield; a second object of the present invention is to provide a method for increasing wood yield.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] 1. Application of overexpression of the strigolactone receptor PtoD14 gene of Populus tomentosa in improving wood yield, wherein the sequence of the strigolactone receptor PtoD14 gene is shown in SEQ ID NO.1.

[0009] Preferably, the wood is Populus tomentosa.

[0010] Preferably, the improvement of timber yield is achieved by increasing plant height and stem thickness.

[0011] Preferably, the improvement of wood yield is by increasing the number of wood layers.

[0012] 2. A method for increasing wood yield, comprising: introducing the PtoD14 gene, a strigolactone receptor of Populus tomentosa, into Populus tomentosa plants by genetic engineering methods to obtain plants that overexpress the PtoD14 gene, i.e., Populus tomentosa with increased wood yield; the sequence of the PtoD14 gene, a strigolactone receptor of Populus tomentosa, is shown in SEQ ID NO.1.

[0013] Preferably, in the present invention, the Populus tomentosa strigolactone receptor PtoD14 gene is driven to express by a xylem-specific promoter LMX5pro, and the nucleotide sequence of the xylem-specific promoter LMX5pro is shown in SEQ ID NO.3.

[0014] Preferably, the genetic engineering method of the present invention is to introduce a recombinant vector containing the PtoD14 gene into Populus tomentosa plants through Agrobacterium-mediated introduction.

[0015] Preferably, the recombinant vector containing the PtoD14 gene is obtained by connecting the nucleotide sequence shown in SEQ ID NO.1 into the BamH I and Sac I restriction sites of the pCAMBIA1300 vector.

[0016] The beneficial effects of the present invention are as follows: the present invention discloses the application of over-expressing the PtoD14 gene, a strigolactone receptor of Populus tomentosa, in improving wood yield. The PtoD14 gene, a strigolactone receptor of Populus tomentosa, is cloned from wild-type Populus tomentosa, and the PtoD14 gene is introduced into Populus tomentosa plants by genetic engineering methods, thereby obtaining a Populus tomentosa strain with enhanced secondary development. The number of secondary xylem cell layers in the 3-month-old PtoD14 gene-transformed Populus tomentosa is 8-21 more than that in the 3-month-old non-transformed ordinary Populus tomentosa. The present invention is of great significance for providing high wood yield for large-scale production of Populus tomentosa. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to make the purpose, technical solution and beneficial effects of the present invention clearer, the present invention provides the following drawings for illustration:

[0018] Figure 1 Identification of positive plants with specific overexpression of LMX5-PtoD14 in Populus tomentosa (A: PCR identification results of wild type and LMX5-PtoD14 overexpression positive lines; B: qPCR identification results of wild type and LMX5-PtoD14 overexpression positive lines);

[0019] Figure 2 The macroscopic phenotypes of the PtoD14-specific overexpressing strains (A: macroscopic phenotypes of wild-type and LMX5-PtoD14-overexpressing plants; B: plant height and stem diameter statistics of wild-type and LMX5-PtoD14-overexpressing plants).

[0020] Figure 3 Section analysis of the PtoD14-specific overexpressing strain (A: section phenotypic analysis of wild-type and LMX5-PtoD14-overexpressing plants; B: statistics of xylem layers in wild-type and LMX5-PtoD14-overexpressing plants). DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0022] Example 1: Cloning of the promoter of the PtoD14 gene of Populus tomentosa

[0023] (1) Extraction of total RNA from Populus tomentosa genome

[0024] Soak the spoon, mortar, pestle, etc. needed for RNA extraction in DEPC water overnight, sterilize with high temperature and high pressure, and then dry for later use. The RNA extraction reagent is operated according to the instructions of the Axygen kit, and the obtained RNA is stored in a -80℃ refrigerator for later use. The specific steps are as follows:

[0025] 1) The fresh plant tissue was quickly wrapped in tin foil and put into liquid nitrogen for quick freezing;

[0026] 2) Grind the sample thoroughly into powder using liquid nitrogen in an RNase-free mortar;

[0027] 3) Transfer the powder to AG buffer, shake thoroughly to mix until it becomes a homogenous slurry, and let it stand at room temperature for 5-10 minutes;

[0028] 4) Refrigerated centrifugation at 4°C, 12,000 rpm / min, 10 min;

[0029] 5) Take the supernatant into a new 1.5 mL EP tube, accurately estimate the volume of the supernatant, add 0.5 times of anhydrous ethanol, and mix well;

[0030] 6) Transfer the mixed solution to a spin clum extraction column and centrifuge at 12000 rpm / min for 1 min;

[0031] 7) Discard the waste liquid in the collection tube, add 500 μL PG buffer to the column, and centrifuge at 12000 rpm / min for 1 min;

[0032] 8) Discard the waste liquid, add 600 μL Wash buffer to the column, and centrifuge at 12000 rpm for 30 seconds;

[0033] 9) Repeat step 8) once;

[0034] 10) Discard the waste liquid and centrifuge the empty tube at 12000 rpm / min for 1 min to remove all the liquid on the filter membrane;

[0035] 11) Add 30-50 μL RElution buffer to the center of the membrane, let stand at room temperature for 2 minutes, and centrifuge at 12000 rpm / min for 1 minute to obtain total RNA;

[0036] 12) Take 1 μL RNA sample and run agarose gel electrophoresis. The extraction quality can be checked by observing the integrity of RNA bands at 28s and 18s.

[0037] (2) Cloning of the PtoD14 gene of Populus tomentosa

[0038] The total RNA of Populus tomentosa genome was extracted, and the total RNA of Populus tomentosa genome was reverse transcribed by reverse transcriptase to obtain the first-strand cDNA. According to the DNA sequence shown in SEQ ID NO.1, the upstream primer and the downstream primer of the complete coding frame were designed and synthesized as follows:

[0039] Upstream primer PtoD14-F: 5′-GGATCCATGAGTAGCCTCATCCTAG-3′ (SEQ ID NO. 4);

[0040] Downstream primer PtoD14-R: 5'-TCTAGATCACCGGGAAAGGGCTCGC-3' (SEQ ID NO. 5);

[0041] The first-strand cDNA obtained by inversion was used as a template, and the upstream primer shown in SEQ ID NO.4 and the downstream primer shown in SEQ ID NO.5 were used as a primer pair. After PCR amplification, sequencing verification was performed to verify that the sequence was correct and the encoded amino acids were as shown in SEQ ID NO.2.

[0042] Example 2: Cloning of the Populus tomentosa LMX5pro promoter

[0043] (1) Extraction of genomic DNA from Populus tomentosa

[0044] The modified CTAB method was used to extract DNA from poplar trees. The method is as follows:

[0045] 1) Take 1 g of fresh wild-type Populus tomentosa leaves in a mortar and grind into powder in liquid nitrogen;

[0046] 2) Add 3 ml of 1% CTAB and 90 μL of β-mercaptoethanol preheated at 65°C, incubate in a 65°C water bath for 30 min, and then take out and bring to room temperature;

[0047] 3) Add chloroform:isoamyl alcohol (V / V 24:1) in equal volumes to CTAB, shake vigorously, place flat, and emulsify for 10 minutes;

[0048] 4) Centrifuge at room temperature, 10,000 rpm, for 10 min;

[0049] 5) Take the supernatant and place it in another centrifuge tube, and repeat steps 3-4;

[0050] 6) Take 1 ml of the supernatant and transfer it to a 2 ml centrifuge tube. Add an equal volume of pre-cooled isopropanol and gently shake until flocculent precipitation appears. Centrifuge at 4°C, 10,000 rpm for 10 min.

[0051] 7) Rinse the precipitate twice with 75% ethanol and once with 100% ethanol, and dry in an oven at 37°C;

[0052] 8) Add 50 μL of ddH2O and 1 μL of RNase, and perform enzymatic treatment at 37°C for 1 h; store at -20°C.

[0053] (2) Cloning of the Populus tomentosa LMX5pro promoter

[0054] The total DNA of Populus tomentosa genome was extracted, and the upstream primer and downstream primer of the complete coding frame were designed and synthesized according to the DNA sequence shown in SEQ ID NO.3, as follows:

[0055] Upstream primer PtoLMX5-F: 5′-GGAATTCCAATGTGGGCCTGGTGTTATAAAG-3′ (SEQ ID NO. 6);

[0056] Downstream primer PtoLMX5-R: 5′-GGGTACCCGGTTGGTGGGGAAAGATGCATC-3′ (SEQ ID NO. 7);

[0057] The first-strand cDNA obtained by inversion was used as a template, and the upstream primer shown in SEQ ID NO.6 and the downstream primer shown in SEQ ID NO.7 were used as a primer pair, and sequencing verification was performed after PCR amplification.

[0058] Example 3: Construction of a recombinant plant expression vector and engineered bacteria containing the PtoD14 gene

[0059] The amplified LMX5pro was connected to the pCAMBIA1300 linearized vector after EocR I and Kpn I digestion by ligase, and transformed into E. coli DH5α, positive clones were screened, and then the plasmid was extracted for PCR detection and enzyme digestion verification to obtain a recombinant plant expression vector containing the LMX5pro promoter, named pCAMBIA1300-LMX5pro vector. The correctness of the gene was confirmed by sequencing by Beijing Qingke Biotechnology Co., Ltd.

[0060] Furthermore, the amplified PtoD14 gene (its DNA sequence is shown in SEQ ID NO.3) was connected to the pCAMBIA1300-LMX5pro linearized vector after BamH I and Xba I digestion by ligase. Escherichia coli DH5α was transformed, positive clones were screened, and then plasmids were extracted for PCR detection and enzyme digestion verification to obtain a recombinant plant expression vector containing the LMX5pro promoter driving the PtoD14 gene, named pCAMBIA1300-LMX5pro: PtoD14 vector. The correctness of the gene was confirmed by sequencing by Beijing Qingke Biotechnology Co., Ltd.

[0061] The pCAMBIA1300-LMX5pro:PtoD14 vector was transformed into Agrobacterium tumefaciens GV3101, and positive clones were screened to obtain an engineered bacterium containing the pCAMBIA1300-PtoD14 vector, which was named GV3101-pCAMBIA1300-LMX5pro:PtoD14.

[0062] Example 4: Agrobacterium tumefaciens-mediated transformation of PtoD14 gene into Populus tomentosa

[0063] (1) Double activation culture of Agrobacterium

[0064] 1) Streak the GV3101-pCambia1300-LMX5pro:PtoD14 strain on YEP solid medium containing 40 mg / L rifampicin and 50 mg / L kanamycin, and culture in a constant temperature incubator at 28°C for 36 hours; pick a single colony and inoculate it into 10 mL YEP+Rif+kan dual-antibody liquid medium;

[0065] 2) 28°C, 200 rpm / min shaking culture for 36-48 hours, until the bacterial solution concentration reaches OD600 = 0.8-1.0;

[0066] 3) According to the ratio of 1:1000, 50 μL of the first live bacterial solution was pipetted into 50 mL of fresh YEP+Rif+kan dual-antibody liquid culture medium for second live liquid culture;

[0067] 4) Incubate at 28°C, 200 rpm / min with shaking for 12-16 hours until the bacterial solution concentration reaches OD600 = 0.3-0.4, and set aside.

[0068] (2) Preparation of Agrobacterium infection solution

[0069] 1) Collect the two-live bacterial solution in a 50 mL centrifuge tube at 4000 rpm / min for 8 min to collect the bacterial cells;

[0070] 2) Discard the culture medium supernatant, resuspend the Agrobacterium in 25 mL of WPM resuspension solution containing AS, and pour the resuspension into a sterile glass bottle;

[0071] 3) The resuspension was placed at 28°C and shaken at 200 rpm / min for 1-2 hours to enhance the infection activity of Agrobacterium.

[0072] (3) Leaf disk preparation

[0073] 1) In a clean bench, burn the sterilized scissors, tweezers, and surgical knife handles with an alcohol lamp for 15 seconds, and let them cool for later use;

[0074] 2) Use scissors to cut off 5-6 leaves of healthy wild-type tissue culture seedlings, place them in a culture dish, and add 1 / 3 volume of sterile water to the dish to keep the leaves moist;

[0075] 3) Place a sterile surgical blade into the handle, burn it with flame, let it cool, and use the blade to cut the leaf into 0.5 cm pieces. 2 Square leaf disk.

[0076] (4) Infection

[0077] 1) Use tweezers to place the leaf disc into the Agrobacterium resuspension solution, gently shake the glass bottle to make the resuspension evenly cover the leaf disc, and infect for 10 minutes;

[0078] 2) After the infection is complete, carefully remove the leaf disc with tweezers, place it on sterile paper, and absorb the excess infection fluid on the leaf disc;

[0079] 3) Place the leaf disc flatly on the co-culture plate, place it in a dark box, and culture it in the dark at 25°C for 36-48 hours.

[0080] (5) Leaf disc selection culture

[0081] 1) After dark culture, select appropriate plant resistance according to the carrier and prepare a selection medium containing antibiotics;

[0082] 2) Transfer the leaf disc to the selective culture medium in a clean bench to induce callus. Replace the leaf disc with a new culture medium every seven days for 3-4 weeks until white or light yellow callus grows on the edge of the leaf disc. The whole process is cultured in a dark box at 25°C.

[0083] (6) Callus induction

[0084] The leaf disc with callus tissue is transferred to the budding medium containing the corresponding antibiotics, and cultured at 8000 Lux and 25°C for 5-6 weeks, with the medium replaced once a week. During this period, the callus tissue will fully grow and expand. Around the 5th week, buds will grow on the callus tissue, and clustered buds will grow.

[0085] (7) Root induction of clustered shoots

[0086] When the clustered buds grow to about 3-5 cm, cut them off with sharp scissors, insert them into the rooting medium with tweezers, and culture them at 8000 Lux and 25°C for 7-10 days to obtain rooted seedlings. These are candidate transgenic plants, which can be transplanted to soil after subsequent positive identification. The transgenic seedlings are named LMX5-PtoD14 plants.

[0087] Example 5: PCR molecular identification of pCAMBIA1300-LMX5pro:PtoD14 transgenic plants

[0088] (1) DNA extraction from wild-type and pCAMBIA1300-LMX5pro:PtoD14 transgenic white poplar

[0089] Select 10 to 15 transgenic resistant regenerated plants and extract the genomic DNA of Populus tomentosa. The method is as follows:

[0090] 1) Prepare CTAB buffer and preheat it in a 65°C water bath;

[0091] 2) Take about 0.5 g of leaves of wild-type and pCAMBIA1300-LMX5pro:PtoD14 transgenic white poplar, grind them into powder in liquid nitrogen, add them to 500 μL of the preheated CTAB extract, and mix well;

[0092] 3) Incubate in a 65°C water bath for 45 min, shaking gently three times to mix.

[0093] 4) After the water bath, cool to room temperature, add equal volumes of chloroform:isoamyl alcohol (24:1), gently invert to mix, and then place flat to emulsify for 10 minutes, 4°C, 12000 rpm / min, and centrifuge for 10 minutes;

[0094] 5) Pipette the supernatant into a new sterile centrifuge tube, add an equal volume of -20°C pre-cooled isopropanol, invert and mix until a white flocculent precipitate is visible;

[0095] 6) Centrifuge at 4°C, 12000 rpm / min for 10 min, remove the supernatant, rinse the precipitate twice with 500 ml 75% (V / V) ethanol, rinse once with 500 ml anhydrous ethanol, and remove the liquid; dry the precipitate in a rotary evaporator at 37°C until it becomes translucent;

[0096] 7) Dissolve the precipitate with 25 μL sterile water to obtain crude DNA extracts from wild-type and pCAMBIA1300-LMX5pro:PtoD14 transgenic white poplar leaves;

[0097] 8) Add about 1 μl RNase to the crude DNA extract and enzymatically digest the RNA at 37°C for 1 hour;

[0098] 9) Store the DNA sample in a -20°C refrigerator for future use.

[0099] (2) PCR amplification of positive plants

[0100] Since wild-type plants do not contain exogenously introduced pCAMBIA1300 vector sequences, the vector pCAMBIA1300-F and pCAMBIA1300-R primers were used for amplification to screen positive plants. The wild-type DNA template was used as a negative control, and the correctly sequenced vector plasmid corresponding to the transgenic plants was used as a positive control. The DNA of the transgenic plants was amplified by PCR and gel electrophoresis imaging to identify the transgenic positive lines ( Figure 1 A). It was found that the target band of 750 bp was amplified only in the pCAMBIA1300-LMX5pro:PtoD14 plasmid DNA and the DNA of L1, L3 and L5-L9. This proved that pCAMBIA1300-PtoD14 was successfully transferred into PtoD14-OE L1, L3 and L5-L9 plants.

[0101] The screening was performed by amplification using the vector pCAMBIA1300-F and the gene primer pCAMBIA1300-R. The sequences of the designed specific primers are as follows:

[0102] pCAMBIA1300-F: 5′-ATGGTGAGCAAGGGCGAGGAGC-3′ (SEQ ID NO. 8);

[0103] pCAMBIA1300-R: 5'-ACTTTATTGCCAAATGTTTGAACG-3' (SEQ ID NO. 9).

[0104] The PCR reaction system was the same as that in Table 2. The reaction procedure was as follows: 94°C pre-denaturation for 3 min, 1 cycle; 94°C denaturation for 30 s, annealing for 30 s, 72°C extension for 1 min, a total of 31 cycles; 72°C extension for 10 min, and 1% agarose gel electrophoresis to detect the amplified product.

[0105] The PCR reaction system is shown in Table 1.

[0106] Table 1. PCR reaction system

[0107]

[0108] (3) RT-qPCR identification of positive plants

[0109] The stems of WT and LMX5-PtoD14 overexpressing plants were sampled, RNA was extracted, and reverse transcribed into cDNA. Fluorescence quantitative PCR was performed using Takara's quantitative enzyme. The reaction system is shown in Table 2, and the amplification primers are as follows:

[0110] qPCR-PtoD14-F: 5′-GATTCTCATCGGAGCATCA-3′ (SEQ ID NO.10)

[0111] qPCR-PtoD14-R: 5′-TACATCCTTAGATGTCTGG-3′ (SEQ ID NO. 11).

[0112] like Figure 1 As shown in B. The results showed that the expression of PtoD14 gene in strains L6-L9 was significantly increased. Among them, L6 and L8 strains were used for further phenotypic analysis.

[0113] Table 2. qPCR system

[0114]

[0115] Amplification was performed using the German Jena fluorescent quantitative gene amplification instrument, and the qPCR program was as follows: pre-denaturation at 95°C for 3 min; 95°C, 30 sec, 60°C, 1 min, 60°C, 30 sec; 95°C, 15 sec, and 40 cycles.

[0116] Example 6: Phenotypic analysis of Populus tomentosa PtoD14 overexpressing plants

[0117] One-month-old tissue culture seedlings were transplanted into pots and grown in a greenhouse at 25°C for three months under long-day conditions (16 hours light / 8 hours dark, light intensity 10,000 lux). The plant height and stem diameter of WT and LMX5-PtoD14 transgenic poplars were measured and counted.

[0118] The results are as follows Figure 2As shown in Figure 2, plant height and stem diameter of LMX5-PtoD14 L6 and L8 plants were significantly increased compared with WT plants ( Figure 2 ).

[0119] Example 7: Analysis of secondary development of LMX5-PtoD14 transgenic plants

[0120] Sections of 3-month-old WT and PtoD14-OE transgenic poplars were observed. Figure 3 As shown in , after overexpression of the PtoD14 gene in the xylem, the number of secondary xylem layers of Populus tomentosa increased significantly.

[0121] The above-described embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art based on the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. Application of overexpression of Populus tomentosa strigolactone receptor PtoD14 gene in increasing wood yield, characterized in that: The sequence of the strigolactone receptor PtoD14 gene is shown in SEQ ID NO.1; the wood is Populus tomentosa; and the method of increasing wood yield is to enhance plant height, stem thickness and increase the number of xylem layers.

2. A method for increasing wood production, characterized in that: The Populus tomentosa strigolactone receptor PtoD14 gene is introduced into Populus tomentosa plants by genetic engineering methods to obtain plants that overexpress the Populus tomentosa strigolactone receptor PtoD14 gene, namely, Populus tomentosa with improved wood yield; the sequence of the Populus tomentosa strigolactone receptor PtoD14 gene is shown in SEQ ID NO.1; the wood is Populus tomentosa; and the improvement of wood yield is achieved by increasing plant height, stem thickness and the number of xylem layers.

3. The method according to claim 2, characterized in that: The Populus tomentosa strigolactone receptor PtoD14 gene is driven to express by the xylem-specific promoter LMX5pro, and the nucleotide sequence of the xylem-specific promoter LMX5pro is shown in SEQ ID NO.

3.

4. The method according to claim 2, characterized in that: The genetic engineering method is to introduce the recombinant vector containing the PtoD14 gene into the Populus tomentosa plant through Agrobacterium-mediated introduction.

5. The method according to claim 4, characterized in that: The recombinant vector containing the PtoD14 gene is obtained by connecting the nucleotide sequence shown in SEQ ID NO.1 into the BamH I and Sac I restriction sites of the pCAMBIA1300 vector.

Images