Coding gene of phoebe bournei PbWRKY55 transcription factor, recombinant expression vector, recombinant bacterium, application and method for improving plant traits

Abstract

The invention belongs to the technical field of plant biology, and particularly relates to a coding gene of a phoebe bournei PbWRKY55 transcription factor, a recombinant expression vector, a recombinant bacterium, application and a method for improving plant traits. The nucleotide sequence of the coding gene of the phoebe bournei PbWRKY55 transcription factor is as shown in SEQ ID NO. 1. By increasing the expression quantity of the coding gene of the phoebe bournei PbWRKY55 transcription factor, the phosphorus absorption of transgenic arabidopsis thaliana can be effectively improved, the symptoms caused by low-phosphorus stress of plants are relieved, and the tolerance of the phoebe bournei PbWRKY55 transcription factor to a low-phosphorus environment is improved. And a new strategy is provided for improving the low-phosphorus-resistant property of the plant and increasing the phosphorus absorption and utilization efficiency of the plant by utilizing a genetic engineering means in the future.

Description

Technical Field

[0001] The invention belongs to the field of plant biotechnology, and specifically relates to a coding gene of Phoebe bournei PbWRKY55 transcription factor, a recombinant expression vector, a recombinant bacterium, and an application and a method for improving plant traits. Background Art

[0002] Phosphorus is one of the elements contained in large quantities in plants. It is an important component of biological macromolecules such as nucleic acids and phospholipids, and participates in many important physiological processes such as plant respiration, photosynthesis and energy transfer. In addition, phosphorus also participates in signal regulation as a signal molecule. Phosphorus deficiency will lead to the accumulation of anthocyanins in plants, slow growth, and affect growth and development processes such as fruiting. The phosphorus element in the soil is mainly organic phosphorus that cannot be directly used by plants. The inorganic phosphorus that can be absorbed and utilized by plants is often less than 10μM in the soil, and it is very easy to lose due to its water solubility, causing plants to often suffer from low phosphorus stress. In order to increase crop yields, phosphorus fertilizers have to be applied, but plants can only absorb 15% to 25% of it. Excess phosphorus fertilizers will enter the environment, causing environmental problems such as eutrophication of water bodies. In addition, plants themselves can maintain the balance of phosphorus in the plant body through the regulation of molecular regulatory mechanisms and physiological and biochemical changes according to the state of phosphorus in the outside world and themselves, and enhance their adaptability under different phosphorus levels. Therefore, on the basis of studying the absorption, utilization and balance mechanism of plant phosphorus, using modern molecular-assisted breeding technology to improve the ability of plant phosphorus absorption and utilization is important for the sustainable development of economic crops and environmental protection. WRKY transcription factors are one of the largest transcription factor families in plants, involved in many important physiological processes such as leaf senescence, seed germination and dormancy, as well as regulating responses to biotic and abiotic stresses. They play an important role in phosphorus stress response and maintaining phosphorus balance in the body.

[0003] Phoebe bournei is a precious tree species, but low-phosphorus soil conditions will affect its economic benefits. The response mechanism of Phoebe bournei to low-phosphorus stress is studied to explore gene resources that are beneficial to improving the absorption and utilization efficiency of Phoebe bournei and enhancing its tolerance to low-phosphorus stress, which is beneficial to the cultivation of Phoebe bournei varieties with low-phosphorus tolerance and improve its cultivation benefits. In view of this, it is necessary to discover a coding gene to encode a transcription factor that can regulate the response to phosphorus stress of Phoebe bournei and maintain the balance of phosphorus in the body. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a coding gene of Phoebe bournei PbWRKY55 transcription factor, a recombinant expression vector, a recombinant bacterium, and an application and method for improving plant traits.

[0005] A first aspect of the present invention provides a gene encoding a PbWRKY55 transcription factor of Phoebe bournei, wherein the nucleotide sequence of the gene encoding the transcription factor is shown in SEQ ID NO.1.

[0006] The second aspect of the present invention provides a recombinant expression vector, which comprises the coding gene as described in the first aspect of the present invention and a backbone plasmid connected to the coding gene.

[0007] Preferably, the backbone plasmid is PBS01.

[0008] Preferably, the recombinant expression vector is constructed by amplifying the PbWRKY55 gene, recovering the PCR product, and obtaining the recombinant expression vector by a seamless cloning method.

[0009] The third aspect of the present invention provides a recombinant bacterium, wherein the recombinant bacterium comprises the recombinant expression vector as described above transformed into an engineered bacterium.

[0010] Preferably, the engineered bacteria is Agrobacterium.

[0011] The fourth aspect of the present invention provides the use of the coding gene of the Phoebe bournei PbWRKY55 transcription factor, the recombinant expression vector or the recombinant bacteria in improving the low-phosphorus tolerance of plants, wherein the plants include Arabidopsis thaliana, and the low-phosphorus refers to an environment in which the phosphorus concentration is 0 μM to 100 μM.

[0012] The fifth aspect of the present invention provides the use of the coding gene of the Phoebe bournei PbWRKY55 transcription factor, the recombinant expression vector or the recombinant bacteria in improving the phosphorus absorption and utilization efficiency of plants, wherein the plants include Arabidopsis thaliana.

[0013] The sixth aspect of the present invention provides a method for improving plant traits, wherein the encoding gene is overexpressed in the plant to obtain an improved plant, wherein the improved trait refers to improved tolerance to a low-phosphorus environment and / or absorption and utilization of phosphorus nutrition; the low-phosphorus refers to an environment with a phosphorus concentration of 0 μM to 100 μM.

[0014] Preferably, the plant comprises Arabidopsis thaliana.

[0015] The present invention has the following beneficial effects:

[0016] The invention provides a coding gene of a Phoebe bournei PbWRKY55 transcription factor. By constructing an overexpression vector containing the coding gene of the Phoebe bournei PbWRKY55 transcription factor, an inflorescence infection method is used to genetically transform Arabidopsis thaliana transformed plants. It is found that overexpressing the coding gene of the Phoebe bournei PbWRKY55 transcription factor can enhance the tolerance to a low-phosphorus environment, improve the absorption and utilization of phosphorus nutrition by the plant, and provide a new strategy for enhancing the tolerance of the plant to a low-phosphorus environment and improving the absorption and utilization efficiency of low phosphorus in the environment by genetic engineering means in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1The quantitative expression results of PbWRKY55 gene in wild-type and transgenic Arabidopsis lines are shown in Figure 1, where Col is the wild-type; OE is the overexpression line;

[0018] Figure 2 The phenotype comparison diagram of the strain overexpressing PbWRKY55 gene and the wild type in the control group CK and low phosphorus concentration medium of 0μM, 10μM, and 100μM, respectively, where Col is the wild type; OE is the overexpression strain;

[0019] Figure 2 In the figure, A is a phenotypic comparison diagram of the strain overexpressing PbWRKY55 gene and the wild type in the CK medium of the control group; B is a phenotypic comparison diagram of the strain overexpressing PbWRKY55 gene and the wild type in the medium with a low phosphorus concentration of 0 μM; C is a phenotypic comparison diagram of the strain overexpressing PbWRKY55 gene and the wild type in the medium with a low phosphorus concentration of 10 μM; D is a phenotypic comparison diagram of the strain overexpressing PbWRKY55 gene and the wild type in the medium with a low phosphorus concentration of 100 μM;

[0020] Figure 3 The phenotypes of wild-type and PbWRKY55-overexpressing transgenic Arabidopsis lines in the control group CK at 20 days; A is Col, B is PbWRKY55-OE9, C is PbWRKY55-OE11, and D is PbWRKY55-OE14;

[0021] Figure 4 The phenotypes of wild-type and PbWRKY55-overexpressing transgenic Arabidopsis lines in the low-phosphorus treatment group LP 20 days; A is Col, B is PbWRKY55-OE9, C is PbWRKY55-OE11, and D is PbWRKY55-OE14;

[0022] Figure 5 Comparison of anthocyanin content in leaves, available phosphorus in roots and leaves and total phosphorus content in wild type and transgenic Arabidopsis lines overexpressing PbWRKY55 at 20 days in the control group CK and the low phosphorus treatment group LP;

[0023] Figure 5A is a comparison of leaf anthocyanin content in the wild type of the control group CK and the low phosphorus treatment group LP 20 days and the transgenic Arabidopsis overexpressing PbWRKY55; B is a comparison of leaf available phosphorus content in the wild type of the control group CK and the low phosphorus treatment group LP 20 days and the transgenic Arabidopsis overexpressing PbWRKY55; C is a comparison of leaf total phosphorus content in the wild type of the control group CK and the low phosphorus treatment group LP 20 days and the transgenic Arabidopsis overexpressing PbWRKY55; D is a comparison of root available phosphorus content in the wild type of the control group CK and the low phosphorus treatment group LP 20 days and the transgenic Arabidopsis overexpressing PbWRKY55; E is a comparison of root total phosphorus content in the wild type of the control group CK and the low phosphorus treatment group LP 20 days and the transgenic Arabidopsis overexpressing PbWRKY55. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below, and preferred embodiments of the present invention are provided. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0026] The present invention uses the following experimental materials:

[0027] Phoebe bournei seeds were collected from the Qingyuan Experimental Forest Farm in Zhejiang Province and stored in the laboratory. Seedlings were cultured in a microclimate-controlled growth chamber purchased from Snijders, the Netherlands, model MC1000; MS medium was purchased from Solarbio, Beijing. The light-dark cycle culture was maintained at 26°C with a light intensity of approximately 50 μmol·m -2 ·s -1 The transgenic recipient was Arabidopsis thaliana of Columbia ecotype, hereinafter referred to as Col. Arabidopsis thaliana was grown in the Arabidopsis growth room of the Intelligent Laboratory Building of Zhejiang A&F University under the following light-dark cycle conditions: at 25°C, with a light intensity of 100 μmol·m- 2 ·s -1 Cultivate for 16 hours, at 22°C, dark for 8 hours, relative humidity of 65%. The nutrient soil is Pin's imported peat soil, supplemented with appropriate amounts of vermiculite and perlite, mixed in a volume ratio of 2:1:1.

[0028] The inventive concept of the present invention is as follows:

[0029] The current experimental research results show that PbWRKY55 is strongly induced in Phoebe leaves under phosphorus deficiency. Since there is currently no complete genetic transformation system for Phoebe, this study is aimed at studying the function of PbWRKY55 under low-phosphorus stress in plants and providing a reference for breeding low-phosphorus tolerant crop varieties using genetic engineering methods.

[0030] Based on this, the first aspect of the present invention provides a gene encoding a transcription factor of Phoebe bournei PbWRKY55, the nucleotide sequence of which is shown in SEQ ID NO.1.

[0031] The second aspect of the present invention provides a recombinant expression vector, which comprises the coding gene according to claim 1 and a backbone plasmid connected to the coding gene.

[0032] The third aspect of the present invention provides a recombinant bacterium, wherein the recombinant bacterium is obtained by transforming the recombinant expression vector into an engineered bacterium.

[0033] The coding gene, recombinant expression vector and recombinant bacteria of the Phoebe bournei PbWRKY55 transcription factor can improve the low-phosphorus tolerance of plants and improve the phosphorus absorption and utilization efficiency of plants.

[0034] The fourth aspect of the present invention provides a method for improving plant traits, wherein the encoding gene is overexpressed in the plant to obtain an improved plant, wherein the improved trait refers to improved tolerance to a low-phosphorus environment and / or absorption and utilization of phosphorus nutrition; the low-phosphorus refers to an environment with a phosphorus content of 0 μM to 100 μM.

[0035] The present invention overexpresses PbWRKY55 in Arabidopsis thaliana by constructing an overexpression vector of the coding gene of the PbWRKY55 transcription factor and heterologous transformation, and analyzes the effect of the overexpression of the gene on the phosphorus absorption and utilization of the plant. It is found that overexpressing the coding gene of the PbWRKY55 transcription factor of Phoebe bournei can enhance the tolerance to low-phosphorus environment and improve the absorption and utilization of phosphorus nutrition of the plant.

[0036] Example 1: Construction of homozygous strains overexpressing the gene encoding the transcription factor PbWRKY55 of Phoebe bournei

[0037] 1. RNA extraction, cDNA synthesis and gene quantitative expression analysis

[0038] The nucleotide sequence of the gene encoding the PbWRKY55 transcription factor of Phoebe bournei is shown as SEQ ID NO.1, and the amino acid sequence of the PbWRKY55 transcription factor of Phoebe bournei is shown as SEQ ID NO.2.

[0039] SEQ ID NO.1:

[0040] ATGGAGCCTCCCTCGCCGGAAAATTCATCAACCAATTGGAGCAAGGCAATCCGGGAGCTGACCCGAGGTCGCGAATTCGCAACCGAGCTCCAAAATCTCCTTCGGAAGGCCGCCGGAGATCTTGAATCGGAGACCGCCGGTGAGCTTGTCGCAAAGATCATGCAATCCTTCGTGGACACCATTTCAATCTTGAATTCCGGCGACAGTCATCGGAATTCGCATGATCCGGCGATTACCAGGGTCGGCGCAGGGGGCCCTGATGAGAACATGATCAAGGATTCTGAGGGGAATATGAAGAATCCGGCTGGCAAAGACCGACGAAGAGGCTACAAGAGAAGAAGATCATCGGTGACATGGACAAAGATCACGCCCTCTCCTTTCATTGATGATCATGGGTGGAGAAAATATGGGCAGAAGGAGATCCTGGGCGCCAAACATCCAAGGAGCTACTTTAGATGCACCCACAGAAATGATCAGGGCTGTCAAGCAACTAAACAAGTGCAAAAGATGGAAGAGGACCCGCCGAATTATCTGATCACTTACATGGGCCATCACACATGCAAAGATCTATCAAGGACTCCTCAAATCATCTTGGATTCGACCACCACTCAGCCATTTTCACTTAGCTTTGATTCGAATTGCATAAGGAAAAGGGATCCTTCCATCTCATCCTCCTCCTTCCTCCCAATAAAACAGGAAGAGAATGAAGAGATTTTTAAAGATTTTACGCCTCATAACTCATCATCATCTTCATCGACATCGGAACATCTCATGCCATTAGATCTTTCAATGTTTGAGTCATGTGGACCGGTGACGAAGCTACCGGCCATCGCGTCGGACGAAGGAGATGTATTTTCCCGGTCGCCGACTAATTCATATAGTTTAGACATGGATATTAAGGTTGATCCAAGTGAATTTGATGAAATCCTTTATTTTGGTGGGGAGGACTTCTTCTAA。

[0041] SEQ ID NO.2:

[0042] MEPPSPENSSTNWSKAIRELTRGREFATELQNLLRKAAGDLESETAGELVAKIMQSFVDTISILNSGDSHRNSHDPAITRVGAGGPDENMIKDSEGNMKNPAGKDRRRGYKRRRSSVTWTKITPSPFIDDHGWRKYGQKEILGAKHPRSYFRCTHRNDQ GCQATKQVQKMEEDPPNYLITYMGHHTCKDLSRTPQIILDSTTTQPFSLSFDSNCIRKRDPSISSSSFLPIKQEENEEIFKDFTPHNSSSSSSTSEHLMPLDLSMFESCGPVTKLPAIASDEGDVFSRSPTNSYSLDMDIKVDPSEFDEILYFGGEDFF.

[0043] Total RNA was extracted from 3-month-old seedlings of Phoebe bournei, reverse transcribed into cDNA, and used as a template to amplify the PbWRKY55 gene using primers shown in SEQ ID NO.3 and SEQ ID NO.4.

[0044] RNA extraction from Phoebe fujianensis and Arabidopsis thaliana was performed according to the instructions of TIANGEN total RNA extraction kit DP432. cDNA reverse transcription kit PrimeScript TM II 1st Strand cDNA Synthesis Kit and real-time fluorescence quantitative analysis kit TBGreen Premix Ex Taq II (Tli RNaseH Plus) were provided by TaKaRa, Dalian, China. The BIO-Rad CFX96 quantitative RT-PCR system was provided by BioRad, USA, and the Bio-Rad CFX Manager (Ver1.5.5.34) software included in the system was used for the experiments and results analysis.

[0045] 2. Construction of PbWRKY55 gene overexpression vector and heterologous transformation of Arabidopsis

[0046] The overexpression vector was PBS01 containing the Ubiquitin promoter, and the vector was linearized with BamHI single enzyme digestion. The Ubi::PbWRKY55 overexpression vector was constructed by seamless cloning. The seamless cloning kit was In-FusionSnapAssemblyMasterMix (TaKaRa). After the vector was successfully constructed, the plasmid was extracted, and robust Arabidopsis thaliana in full flowering period was selected to transform Arabidopsis thaliana using the Agrobacterium dip method. The seeds of the infected plants were harvested and screened on 1 / 2MS medium containing 10μg / mL herbicide Basta. PCR detection was performed, and the correct strains were identified and harvested until the T3 generation transgenic homozygous strains were obtained.

[0047] 3. Quantitative analysis of transgenic lines overexpressing PbWRKY55 gene in Phoebe bournei

[0048] After obtaining homozygous strains, real-time fluorescence quantitative PCR was used to explore the expression of PbWRKY55 gene in different transgenic strains. Using AtActin as the reference gene, PbWRKY55 gene quantitative primers PbWRKY55-F and PbWRKY55-R were designed, and the primer sequences are shown in SEQ ID NO.3 to SEQ ID NO.8 in Table 1.

[0049] Table 1 Related primer sequences

[0050]

[0051] 4. Results

[0052] like Figure 1 As shown in the figure, the real-time fluorescence quantitative results showed that the PbWRKY55 gene was not expressed in the wild-type Col, but its expression level increased significantly in other transgenic lines, and the expression level difference between lines was large. Three lines were selected according to the expression level: PbWRKY55-OE9, PbWRKY55-OE1 and PbWRKY55-OE14 as transgenic line experimental materials. For the convenience of writing, OE9, OE11 and OE14 are used to represent PbWRKY55-OE9, PbWRKY55-OE22 and PbWRKY55-OE14 lines in the following text.

[0053] Example 2 Effect of low phosphorus treatment on Arabidopsis plants overexpressing PbWRKY55 during culture

[0054] 1. Low phosphorus treatment in medium for Arabidopsis thaliana overexpressing PbWRKY55 and wild-type plants

[0055] Low phosphorus treatment: Wild-type Arabidopsis and three overexpression lines OE9, OE11 and OE14 were sown in normal 1 / 2MS medium. The medium with different phosphorus concentrations was 0μM phosphorus medium, 10μM phosphorus medium and 100μM phosphorus medium. The normal 1 / 2MS medium was used as the control group CK, and the phosphorus content was 625μM. The specific configuration method is as follows:

[0056] Normal 1 / 2MS culture medium: weigh 0.77g of MS culture medium, with a final concentration of 2.2g / L; 3.5g of sucrose, with a final concentration of 10g / L, dissolved in 350mL of water, adjust the pH to 5.7-6.0, then add 1.225g of phytogel, with a final concentration of 3.5g / L, sterilize at 121℃ for 20min, and pour into each culture dish with about 35mL.

[0057] Phosphorus-free Arabidopsis growth medium: Take 0.75g of phosphorus-deficient 1 / 2MS culture medium base salt, with a final concentration of 2.14g / L; 3.5g of sucrose, with a final concentration of 10g / L, dissolved in 350mL of water, adjust the pH to 5.7-6.0, then add 1.225g of phytogel, with a final concentration of 3.5g / L, sterilize at 121℃ for 15min, and pour into each culture dish with about 35mL.

[0058] Low-phosphorus-treated Arabidopsis growth medium containing 10μM and 100μM phosphorus: Take 0.75g of phosphorus-deficient 1 / 2MS medium base salt, with a final concentration of 2.14g / L; 3.5g of sucrose, with a final concentration of 10g / L, dissolved in 350mL of water, and add 16μL and 160μL of 29.75mg / mL potassium dihydrogen phosphate mother solution, respectively, so that the phosphorus content of the final medium is 10μM and 100μM. Adjust the pH to 5.7-6.0, then add phytogel 1.225g, with a final concentration of 3.5g / L, sterilize at 121℃ for 20min, and pour about 35mL per culture dish. The seeds of each strain are evenly sown on a straight line 1cm away from one side of the culture dish. In each culture dish, three seeds of the wild type and three transgenic strains are sown, with a total of 12 seeds in one row, and 3 replicates per plate. After sowing, seal with breathable tape and vernalize at 4℃ for 2 days, then place vertically in the growth chamber with the side closest to the seeds at the top, so that the plant grows parallel to the bottom of the culture dish. Observe the growth of transgenic lines and wild-type Arabidopsis. After about 20 days, carefully remove three Arabidopsis plants of the same line from the culture medium, carefully wash off the culture medium in water, and take pictures.

[0059] 2. Results

[0060] Wild-type Arabidopsis and three PbWRKY55 overexpression lines were sown in normal culture medium and 0μM, 10μM, and 100μM low-phosphorus culture medium. After about 2 weeks, it was found that, regardless of the wild type or transgenic lines, as the phosphorus concentration in the low-phosphorus culture medium decreased, the aboveground part of the plant became smaller, the purple color of the leaves caused by the accumulation of anthocyanins gradually worsened, the root length became shorter, and the lateral roots increased. These are typical symptoms of phosphorus stress in Arabidopsis plants.

[0061] like Figure 2 As shown in the figure, in normal culture medium, the leaf color and size and root length of the three transgenic lines overexpressing PbWRKY55 were similar to those of the wild type. In the 100 μM phosphorus-deficient medium, the aboveground biomass of the three transgenic lines increased significantly compared with the wild type. The root system was also relatively less inhibited, and the growth was better than that of the wild type. In the 10 μM phosphorus medium, the growth of the transgenic lines was better than that of the wild type. The leaves of the wild type began to turn yellow and senesce, while the three transgenic lines still maintained relatively normal growth. In the phosphorus-deficient medium, the wild type was completely unable to grow due to severe phosphorus deficiency, and the root development was severely inhibited, while the growth of the aboveground and root systems of the transgenic lines was less inhibited than that of the wild type. These results all indicate that overexpression of PbWRKY55 in Arabidopsis can improve the tolerance of transgenic plants to low phosphorus. It reduces the effects of low phosphorus stress on plant growth and development.

[0062] Example 3 Effect of low phosphorus treatment on Arabidopsis plants overexpressing PbWRKY55 during soil culture

[0063] 1. Low phosphorus treatment of Arabidopsis thaliana overexpressing PbWRKY55 and wild-type plants

[0064] Wild-type Arabidopsis and three transgenic lines were sown in normal 1 / 2MS medium and transplanted after true leaves expanded.

[0065] Prepare nutrient soil, nutrient soil composition, nutrient soil composition by volume fraction: 50% peat soil, 25% perlite, 25% vermiculite, mix well, add 120g of nutrient soil to each seedling pot, and flatten it to make it uniform in thickness. Among them, the size of peat soil is 1mm~10mm, the size of perlite is 3mm~6mm, the size of vermiculite is 1mm~3mm, and the size of seedling pot is 35cm×20cm×3cm. Spray an appropriate amount of water with a kettle to moisten the nutrient soil. A seedling tray is divided into four parts, and the wild type and 3 transgenic strains are transplanted respectively, with 12 seedlings of each strain.

[0066] After transplanting, cover with a transparent plastic cover and open it after two days. Use a wash bottle to evenly water with an equal amount of normal 1 / 4 Hoagland nutrient solution with a phosphorus content of 7.75 mg / L as the control group CK, and 1 / 4 Hoagland nutrient solution without phosphorus as the low phosphorus treatment group LP every day. The amount of watering depends on the soil moisture. Water until the soil is moist but no excess water seeps out. The treatment lasts about 20 days.

[0067] After the treatment, the anthocyanin content in the leaves of the wild-type and transgenic plants, and the available phosphorus and total phosphorus contents in the root and leaf tissues were measured.

[0068] 2. Results

[0069] The effects of phosphorus deficiency on PbWRKY55 overexpression lines were studied under substrate soil culture conditions. Figure 3 and Figure 4 As shown in the figure, after 20 days, the plants in the low phosphorus treatment group LP showed obvious phosphorus deficiency phenotypes, while the wild type and transgenic lines in the control group CK grew normally and were in good condition. Under low phosphorus treatment, anthocyanin accumulation in the leaves of wild-type Arabidopsis was obvious, and the growth of the aboveground part was inhibited. The overall growth of the transgenic lines was better than that of the wild type. The anthocyanin content of the three PbWRKY55 overexpression lines was significantly lower than that of the wild type. The anthocyanin content of the transgenic lines was only 6.6% to 16.5% of that of the wild type, and the growth of the aboveground part of the plants was also significantly better than that of the wild type. This shows that the overexpression of the PbWRKY55 gene alleviates the damage of low phosphorus stress to the plants.

[0070] In addition, the contents of available phosphorus and total phosphorus in leaves of the three transgenic lines of PbWRKY55 were higher than those of the wild type in both the control group CK and the low phosphorus treatment group LP. In roots, the transgenic lines only showed an increase in phosphorus content under low phosphorus treatment, among which the available phosphorus contents in roots of PbWRKY55-OE9 and PbWRKY55-OE14 were 168% and 161% higher than those of the wild type, respectively. Figure 5 These results indicate that increasing the expression of PbWRKY55 in plants can promote the absorption of phosphorus by roots, and that PbWRKY55 is also involved in the transport of phosphorus from root tissue to leaf tissue. It can be used to improve the ability of plants to absorb phosphorus in low-phosphorus environments and improve plant tolerance to low-phosphorus environments.

[0071] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0072] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A gene encoding a transcription factor of PbWRKY55 from Phoebe bournei, characterized in that: The nucleotide sequence of the coding gene is shown in SEQ ID NO.

1.

2. A recombinant expression vector, characterized in that: The recombinant expression vector comprises the coding gene according to claim 1 and a backbone plasmid connected to the coding gene.

3. The recombinant expression vector according to claim 2, characterized in that: The backbone plasmid is PBS01.

4. The recombinant expression vector according to claim 2, characterized in that: The method for constructing the recombinant expression vector is to amplify the PbWRKY55 gene, recover the PCR product, and obtain the recombinant expression vector by a seamless cloning method.

5. A recombinant bacterium, characterized in that: The recombinant bacteria are obtained by transforming the recombinant expression vector described in claim 2 into engineered bacteria.

6. The recombinant bacterium according to claim 5, characterized in that The engineered bacteria is Agrobacterium.

7. Use of the Phoebe bournei PbWRKY55 transcription factor gene according to claim 1, the recombinant expression vector according to claim 2 or the recombinant bacterium according to claim 5 in improving plant low-phosphorus tolerance, characterized in that: The plant includes Arabidopsis thaliana, and the low phosphorus refers to a phosphorus concentration in the environment of 0 μM to 100 μM.

8. Use of the Phoebe bournei PbWRKY55 transcription factor gene of claim 1, the recombinant expression vector of claim 2 or the recombinant bacterium of claim 5 in improving plant phosphorus absorption and utilization efficiency, characterized in that: The plants include Arabidopsis thaliana.

9. A method for improving plant traits, characterized in that: The improved plant is obtained by overexpressing the encoding gene of claim 1 in the plant, wherein the improved trait refers to improved tolerance to low-phosphorus environment and / or absorption and utilization of phosphorus nutrition; the low-phosphorus refers to an environment with a phosphorus concentration of 0 μM to 100 μM.

10. The method according to claim 9, characterized in that The plants include Arabidopsis thaliana.

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