CN112219863B

CN112219863B - Application of phytophthora capsici effector factor RxLR121504 in promoting plant growth

Info

Publication number: CN112219863B
Application number: CN202011053215.1A
Authority: CN
Inventors: 张修国; 朱春原; 盛慧; 艾聪聪; 杨灿灿
Original assignee: Shandong Agricultural University
Current assignee: Shandong Agricultural University
Priority date: 2020-09-29
Filing date: 2020-09-29
Publication date: 2021-06-29
Anticipated expiration: 2040-09-29
Also published as: CN112219863A

Abstract

The invention discloses application of a phytophthora capsici effector factor RxLR121504 in promoting plant growth. The invention utilizes protein expression technology to prepare the phytophthora capsici effector RxLR121504 escherichia coli high-efficiency expression strain to obtain an RxLR121504 protein solution, and further proves that the RxLR121504 has the performance of promoting the growth and the vigor of roots of hot pepper, cucumber and tomato seedlings, and is expected to be developed into a novel protein preparation for strengthening the roots and the seedlings of vegetables.

Description

Application of phytophthora capsici effector factor RxLR121504 in promoting plant growth

Technical Field

The invention relates to the technical field of biology, in particular to application of phytophthora capsici effector RxLR121504 in promoting plant growth.

Background

Plants are subject to various biotic and abiotic stresses in nature and, in order to avoid these disturbances, plants have evolved various means of defense. When the pathogenic bacteria invade the plant cells, barrier reaction is often formed on the surfaces of the plant cells to prevent the invasion of the pathogenic bacteria, and if the pathogenic bacteria successfully break through the barrier on the surfaces of the plant cells, the plant cell membrane receptor can sense the invasion of the pathogenic bacteria, so that the immune system of the plant is started, and the host plant is induced to generate immune reaction.

During the process that plant pathogenic bacteria infect plant hosts, RxLR effector factors are often secreted and generated, the RxLR effector factors are combined with host target proteins to interfere the immune system of the plant and promote the infection and the pathogenicity of the pathogenic bacteria, but host plants also correspondingly evolve a defense system to recognize and prevent the infection and the pathogenicity of the pathogenic bacteria, so that the expression of plant resistance proteins, the burst of active oxygen, the deposition of callose and even the generation of allergic necrosis reaction (HR) are stimulated, and the expansion of pathogenic oomycetes is inhibited. Such RxLR effectors are often referred to as immune effector molecules.

The genomes of some important plant pathogenic oomycetes, such as potato late blight (Phytophthora infestans), soybean Phytophthora (Phytophthora sojae), tobacco Phytophthora (Phytophthora parasitica) and pepper Phytophthora capsici (Phytophthora capsicii) all contain hundreds of RxLR effect factors, wherein some RxLR effect molecule members have immune performance, the immune characteristics of the RxLR effect molecules are cloned and correctly identified, and the application prospect of the immune RxLR effect molecules is further proved to have important significance by means of gene expression and protein purification technology.

Disclosure of Invention

The invention aims to provide application of a phytophthora capsici effector RxLR121504 in promoting plant growth.

In order to achieve the object, the invention provides, in a first aspect, application of phytophthora capsici effector RxLR121504 in promoting plant growth.

The effector factor RxLR121504 is cloned from phytophthora capsici strain LT1534, and the amino acid sequence of the effector factor RxLR121504 is shown in SEQ ID NO. 2.

In the application, the phytophthora capsici effector RxLR121504 is prepared into a protein solution, or the escherichia coli bacterial liquid expressing the phytophthora capsici effector RxLR121504 or the diluent thereof is applied to the soil or seedling culture medium around the plant rhizosphere.

In the application, the phytophthora capsici effector RxLR121504 is prepared into a protein solution, or the escherichia coli bacterial liquid expressing the phytophthora capsici effector RxLR121504 or a diluent thereof is used for root irrigation of the strain.

In the application, the phytophthora capsici effector RxLR121504 is prepared into a protein solution, or the Escherichia coli liquid expressing the phytophthora capsici effector RxLR121504 or a diluent thereof is subjected to seed soaking treatment.

In the application, the phytophthora capsici effector RxLR121504 encoding gene is introduced into a plant through a plasmid or is integrated on a plant chromosome through a genetic engineering means, so that the plant expresses the phytophthora capsici effector RxLR 121504.

In the invention, the Escherichia coli expressing the phytophthora capsici effector RxLR121504 is obtained by introducing the phytophthora capsici effector RxLR121504 coding gene into an Escherichia coli competent cell through a plasmid.

Preferably, the plasmid is pET28 a.

Preferably, the E.coli competent cell is DH5 alpha.

In the present invention, the plants include, but are not limited to, pepper, cucumber, and tomato.

In a second aspect, the invention provides an application of a phytophthora capsici effector factor RxLR121504 and a prokaryotic or eukaryotic expression system for expressing the phytophthora capsici effector factor RxLR121504 in preparation of a plant growth promoter.

In a third aspect, the invention provides a plant growth promoter, the active ingredients of which are phytophthora capsici effector RxLR121504 and/or a prokaryotic or eukaryotic expression system for expressing the phytophthora capsici effector RxLR 121504.

By the technical scheme, the invention at least has the following advantages and beneficial effects:

the invention utilizes protein expression technology to prepare the phytophthora capsici effector RxLR121504 escherichia coli high-efficiency expression strain to obtain an RxLR121504 protein solution, and further proves that the RxLR121504 has the performance of promoting the growth and the vigor of roots of hot pepper, cucumber and tomato seedlings, and is expected to be developed into a novel protein preparation for strengthening the roots and the seedlings of vegetables.

Drawings

FIG. 1 is a map of pET28a vector.

FIG. 2 shows the result of PCR amplification of the RxLR121504 gene in a preferred embodiment of the present invention. Wherein, M: DNA Marker, 1-4: the RxLR121504 gene DNA PCR amplified band.

FIG. 3 is a SDS-PAGE gel of RxLR121504 expression in a preferred embodiment of the invention. Wherein, M: a protein Marker; 1-3: IPTG induces RxLR121504 protein expression; CK: and (6) comparison.

FIGS. 4 and 5 show that RxLR121504 protein promotes root development of pepper seedlings in a preferred embodiment of the present invention.

FIG. 6 shows that RxLR121504 protein promotes root development of cucumber seedlings in a preferred embodiment of the present invention.

FIG. 7 shows that RxLR121504 protein promotes cucumber seedling root growth in a preferred embodiment of the present invention.

FIG. 8 shows that RxLR121504 protein promotes root development of tomato seedlings in a preferred embodiment of the present invention.

FIG. 9 shows that RxLR121504 protein promotes tomato seedling growth in a preferred embodiment of the present invention.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention. Unless otherwise indicated, the examples follow conventional experimental conditions, such as the Molecular Cloning handbook, Sambrook et al (Sambrook J & Russell DW, Molecular Cloning: a Laboratory Manual, 2001), or the conditions as recommended by the manufacturer's instructions.

Example 1 cloning and expression of Phytophthora capsici Effector RxLR121504 Gene

1. Phytophthora capsici effector molecule RxLR121504 gene information prediction

By means of bioinformatics DNAMAN software, the whole genome https:// genome. jgi. doe. gov/portal/, phytophthora capsici was analyzed and compared, and 1 important RxLR effector molecule was screened and defined, which is named as RxLR121504 effector, and the encoded gene of the effector molecule has the size of 378bp (containing a signal peptide 60bp, SEQ ID NO:1), comprises 126 amino acid residues (SEQ ID NO:2), has the molecular weight of 14.8KDa, and has the pI of 10.2. SignalP 4.0Server (http:// www.cbs.dtu.dk/services/SignalP /) was used to predict signal peptide, which has a signal peptide region of 1-60bp and no transmembrane region.

2. Phytophthora capsici effector molecule RxLR121504 gene clone sequencing

2.1 strains of Phytophthora capsici

The highly pathogenic phytophthora capsici strain LT1534 is provided by vegetable pest biology focus laboratory of Shandong university of agriculture.

2.2 RNA extraction and reverse transcription of cDNA from strains of Phytophthora capsici LT1534

The laboratory-stored highly pathogenic strain LT1534 was cultured using V8 plates in a 28 ℃ incubator, and RNA extraction was performed as follows:

1) grinding a sample: grinding phytophthora capsici LT1534 mycelia into powder by using a mortar precooled by liquid nitrogen;

2) homogenizing: taking 1g of mycelium ground powder, adding 10mL of Trizol, fully homogenizing for 2min by an electric vortex instrument, standing for 3-5min at room temperature to fully crack;

3) centrifuging at 12000rpm at 4 deg.C for 10min, sucking supernatant and removing precipitate;

4) adding chloroform into 200 mu L chloroform/mL Trizol, shaking and mixing uniformly (a vortex shaking instrument is not used), standing for 15min at 25 ℃, and centrifuging for 15min at the rotation speed of 13000rpm at 4 ℃;

5) absorbing the upper water phase into a new centrifugal tube, discarding the lower phenol phase without absorbing the middle interface, wherein the phenol phase is used for extracting protein;

6) adding 500 mu L of isopropanol into 1mL of Trizol, reversing the mixture, and standing the mixture at room temperature for 5-10 min;

7) centrifuging at 4 deg.C and 12000rpm for 10min, and removing supernatant;

8) adding ethanol according to the proportion of 1mL of 75% ethanol/mL of Trizol, gently inverting, centrifuging at the temperature of 4 ℃ and the rotation speed of 8000rpm for 5min, and removing the supernatant as much as possible;

9) standing at room temperature, air drying or oven drying for 5-10min, removing ethanol, and preventing RNA sample from drying excessively or dissolving;

10) using 50 μ L H₂O, TE buffer solution or 0.5% SDS, DEPC treatment of the solvent and autoclaving at 121 ℃ for 30 min;

11) OD measurement using ultraviolet spectrophotometry₆₀₀，A₂₆₀/A₂₈₀1.8-2.0，A₂₆₀/A₂₃₀1.8-2.2, which shows that the purity of RNA meets the experimental requirements.

Synthesizing cDNA by reverse transcription of RNA, and the process is as follows:

1) RNA reverse transcription is carried out on the RNA, an RNase removing centrifugal tube is prepared into a PCR system, and the preparation system is shown in table 1.

TABLE 1 RT-PCR reaction System

Sucking, beating and mixing after mixing, centrifuging and placing on ice.

2) Incubating at 50 deg.C for 15min, incubating at 85 deg.C for 2min, and immediately subjecting the product to PCR reaction, or storing at-20 deg.C for half a year; the long-term preservation is recommended to be carried out after subpackaging and then storing in a freezer at the temperature of-80 ℃, and repeated freeze thawing of cDNA is avoided.

2.3 RxLR121504 Gene PCR cloning primer design

A pair of specific primers is designed according to the sequence of the RxLR121504 gene (minus the sequence of a signal peptide) in the whole genome https of phytophthora capsici// genome.jgi.doe.gov/portal/recombinant vector and two enzyme cutting sites NcoI and NotI of a recombinant vector pET28a (Novagen):

upstream primer RxLR 121504F: 5'-CATGCCATGGGCATGCGCTTCTCCTACGTTCTTTT-3'

Downstream primer RxLR 121504R: 5'-CCGCTCGAGTTTTCCCTTTGCCAGCTTGT-3'

For later purification of RxLR121504 protein, the C-terminal his tag of pET28a vector was properly translated, and the stop codon of RxLR121504 was removed. The primer is synthesized by Qingdao Optimaxi biotechnology Limited. The map of the pET28a vector is shown in FIG. 1.

2.4 purpose RxLR121504 gene PCR amplification

The target fragment was amplified from the cDNA by polymerase chain reaction, the PCR reaction system is shown in Table 2.

TABLE 2 RxLR121504 Gene PCR amplification System

The PCR amplification product is shown by agarose gel electrophoresis (figure 2), and the amplification band is about 300bp and is basically consistent with the size of the target gene band. The PCR amplified target gene fragment is recovered by using a gel recovery kit (DNA recovery kit), and the recovered product can be stored for later use at the temperature of minus 20 ℃ for a short time. The PCR amplification result of the target RxLR121504 gene is shown in FIG. 2.

3. Recombinant vector construction

3.1 double digestion of target Gene and vector

The RxLR121504 gene PCR amplification gel recovery product and the vector pET28a are subjected to double enzyme digestion by enzyme 1(NcoI) and enzyme 2(XhoI) respectively, and are subjected to water bath at 37 ℃ for 2-3 h, wherein the enzyme digestion system is shown in Table 3. The RxLR121504 and the vector pET28a after the enzyme digestion were recovered by using a gel recovery kit, and the double-enzyme digestion reaction system is shown in Table 3.

TABLE 3 double digestion reaction System for RxLR121504 and vector pET28a

3.2 connection of the target Gene RxLR121504 to the vector pET28a

The digested RxLR121504 gene DNA fragment was recovered from pET28a (Novagen) and ligated with solution I (solution I) at 16 ℃ for 3h, as shown in Table 4.

TABLE 4 RxLR121504 ligation into vector pET28a reaction System

3.3 transformation of the recombinant vector pET28a into E.coli DH 5. alpha. competent cells

1) Melting 50 μ L DH5 α competent cells in ice bath, adding ligation product, mixing gently, and ice-cooling for 30 min;

2) carrying out water bath heat shock for 90s at 42 ℃, and then rapidly carrying out ice bath on the centrifugal tube for 2 min;

3) adding 500 mu L of sterile LB culture medium (without antibiotics) into each centrifuge tube on a super clean bench, uniformly mixing, placing at 37 ℃, performing shaking culture at 200rpm for 45-60 min, and ensuring that host bacteria are completely recovered;

4) centrifuging for 1min at 8000rpm of a normal temperature centrifuge, discarding part of supernatant, resuspending with a pipette thallus, uniformly mixing, coating on an LB agar culture medium (containing corresponding antibiotics), and then performing inverted culture in an incubator at 37 ℃ for 12-16 h.

3.4 identification of the recombinant vector pET28a

After bacterial plaque grows on the plate by the prepared competent cells, adding 1mL of sterile LB liquid medium (containing corresponding antibiotics) into a 1.5mL centrifuge tube, selecting the grown single bacterial colony, placing the single bacterial colony in the LB liquid medium centrifuge tube, carrying out shake culture at 37 ℃ for 5-6 h to serve as a bacterial liquid PCR template, and carrying out bacterial liquid PCR identification at proper time, wherein a bacterial liquid PCR reaction system is shown in Table 5.

TABLE 5 PCR reaction System for recombinant vector pET28a bacterial liquid

And (3) carrying out agarose gel electrophoresis identification on the bacteria liquid PCR reaction sample, taking the bacteria liquid with the PCR amplification result as a positive sample, taking 500 mu L of the bacteria liquid with the positive sample, sending the bacteria liquid to Qingdao Tingxi biotechnology Limited company for sequencing, comparing and analyzing the sequencing result with a genome sequence by using DNAman software, taking 500 mu L of the bacteria liquid with the correct sequencing result, adding 500 mu L of 50% sterilized glycerol, storing in a freezer at the temperature of-20 ℃, taking another bacteria liquid with the correct sequencing result, extracting plasmids, and storing in a freezer at the temperature of-20 ℃ for later use, wherein the plasmid extraction is carried out according to the instruction of the CWBIO high-purity plasmid miniextraction kit.

RxLR121504 recombinant protein expression

4.1 assay of RxLR121504 recombinant protein expression

1) The pET28a recombinant plasmid with correct sequencing is transformed into an E.coli Rosetta (DE3) strain, centrifuged for 1min at 8000rpm of a normal-temperature centrifuge, a part of supernatant is discarded, a pipettor is used for carrying out heavy suspension, the mixture is uniformly mixed and then coated on an LB agar plate culture medium (containing corresponding antibiotics), and then the inverted culture is carried out for 12 to 16 hours in an incubator at 37 ℃;

2) selecting a single bacterial strain, inoculating the single bacterial strain into a centrifugal tube filled with 1.5mL of LB liquid medium (added with Kan resistance), and carrying out shake culture at 37 ℃ and 180rpm for 6 h;

3) inoculating 1mL of shake culture solution into LB liquid culture medium (adding Kan resistance) containing 1.5mL, and culturing to OD₆₀₀Taking 1mL of bacterial liquid as a control before induction, wherein the bacterial liquid is 0.6-0.8;

4) adding Inducer (IPTG) with different concentrations into the induced bacteria liquid and the control bacteria liquid respectively, and inducing at 37 ℃ and 180rpm for 3 h;

5) after induction, 1mL of bacterial liquid is taken respectively, and is centrifuged for 1min at 12000rpm simultaneously with the control; discarding the supernatant, adding 40 μ L of 2 × binding buffer solution respectively, resuspending and mixing, then adding 40 μ L of 2 × loading buffer solution, and mixing;

6) boiling the sample for 15min, oscillating for 1 time at 5min intervals, oscillating for 2 times, and centrifuging at 12000rpm for 1min before SDS-PAGE electrophoresis;

7) taking 20 mu L of sample to carry out SDS-PAGE electrophoresis, observing the expression condition of the target protein, and determining that the appropriate concentration of an Inducer (IPTG) is 0.5 mM;

8) taking 500 mu L of the expression target protein bacterial liquid, adding 500 mu L of 50% sterilized glycerol, mixing uniformly, filling into a sterilized freezing storage tube, and storing in a freezer at the temperature of-20 ℃.

And then detecting the expression condition of the target protein by using an SDS-PAGE electrophoresis technology, wherein the SDS-PAGE electrophoresis result shows that, compared with a control, after the pET28a-RxLR121504 protein is induced by a proper concentration Inducer (IPTG), the RxLR121504 is induced to express a protein with a molecular weight of 12KDa (signal peptide is removed), the molecular weight of the protein is consistent with the predicted molecular weight of the RxLR121504, which shows that the pET28a-RxLR121504 protein prokaryotic expression system is successfully constructed, and the result is shown in figure 3.

4.2 Large-scale expression of RxLR121504 fusion protein

1) Activating the preserved strain with higher expression level, inoculating the strain into 1L LB liquid culture medium containing 50mg/mL Kan according to the proportion of 1:100, and performing shake culture at 37 ℃ and 180rpm for 3-4 h to ensure the OD of the strain₆₀₀＝0.6～0.8；

2) Ensuring the temperature of the shaking table to be reduced to 16 ℃ in advance, adding an Inducer (IPTG) with the final concentration of 1mM, and inducing at the temperature of 16 ℃ for 16-21 h overnight at 120rpm to ensure OD₆₀₀The value is 1.8-2.0, the OD value is monitored by using an ultraviolet spectrophotometer when the induction time reaches 16 hours, and the OD value is monitored for 1 time every 1 hour;

OD value: the optical density of the protein to be detected is shown, and 1OD Escherichia coli ≈ 10⁸-10⁹Cell/ml.

Example 2 application of RxLR121504 protein in promotion of root development and growth of seedlings of hot pepper, cucumber and tomato

1. Technology for promoting root development and seedling growth of pepper, cucumber and tomato seedlings by using RxLR121504 protein

1) Following the procedure of example 1, a large amount of bacterial suspension containing RxLR121504 protein was prepared by induction, and OD was monitored₆₀₀The value is about 1.8-2.0, and the product is stored overnight at 4 ℃ and is used for seedling pre-treatment of pepper, cucumber and tomato seeds.

2) OD reduction with sterile Water₆₀₀Diluting the bacterial suspension with the value of 1.8-2.02-3 times, before seedling raising of pepper, cucumber and tomato seeds, the diluent is mixed and applied to a seedling raising substrate (wood dust is taken as a main substrate, a mixture of dried chicken manure and fermented dried pig manure in a mass ratio of 1:1 is taken as an organic fertilizer source, 5 treatments are set according to a volume ratio, and the nutrient content is N0.3g/kg and P is added₂O₅0.5 g/kg and K₂O1.5 g/kg of a quick-acting chemical fertilizer), the amount of the diluted solution of the bacterial suspension, i.e., 100ml of the seedling substrate, 100kg, and the bacterial solution of DH5 α transformed with the empty vector of pET28a was induced by IPTG to serve as a Control (CK).

2. Analysis of results of RxLR121504 protein solution for promoting root development and growth of pepper, cucumber and tomato seedlings

1) The analysis of the results of the RxLR121504 protein on promoting the development of the root system of the pepper seedlings and the growth thereof is shown in FIG. 4 and FIG. 5.

Comparative analysis the results in FIG. 4 show that the average length of the young root is 4.2cm (30 statistical seedling roots) in the 5-leaf stage of the pepper seedlings treated with RxLR121504 protein, while the average length of the young root is 2.1cm (30 statistical seedling roots) in the 5-leaf stage of the pepper seedlings treated with control CK, the former is 2.3cm longer than the latter. Comparative analysis the results in FIG. 5 show that at 6-leaf stage of the pepper seedlings treated with RxLR121504 protein, the average height of the seedlings was 7.5cm (30 statistical seedlings height), while at 6-leaf stage of the control CK-treated pepper seedlings, the average height of the seedlings was 4.5cm (30 statistical seedlings height), the average height of the former was increased by 3cm compared to the average height of the latter roots. Therefore, the RxLR121504 protein can obviously promote the development and growth of the root system of the pepper seedling.

2) The analysis of the results of the development of the RxLR121504 protein into root systems of cucumber seedlings and the growth thereof are shown in FIGS. 6 and 7.

Comparative analysis the results in FIG. 6 show that at 5-leaf stage of cucumber seedlings treated with RxLR121504 protein, the average length of the young root is 6.5cm (30 statistical seedling roots), while at 5-leaf stage of control CK-treated cucumber seedlings, the average length of the young root is 4.5cm (30 statistical seedling roots), the former is 2.0cm longer than the latter.

The results of comparative analysis in FIG. 7 show that the mean height of seedlings at the 5-6 leaf stage of cucumber seedlings treated with RxLR121504 protein is 19.5cm (counting 30 seedlings), while the mean height of seedlings at the 5-6 leaf stage of cucumber seedlings treated with control CK is 15.5cm (counting 30 seedlings), the mean height of the former is increased by 4cm compared with the mean height of the latter roots, thus the RxLR121504 protein can obviously promote the development and growth of root systems of cucumber seedlings.

3) The analysis of the results of the development of the RxLR121504 protein into the root system of tomato seedlings and the growth thereof are shown in FIG. 8 and FIG. 9.

Comparative analysis the results in FIG. 8 show that the mean length of the young roots is 3.5cm (statistics of 30 seedling roots) in the 5-leaf stage of tomato seedlings treated with RxLR121504 protein, while the mean length of the young roots is 2.1cm (statistics of 30 seedling roots) in the 5-leaf stage of tomato seedlings treated with control CK, the former is 1.4cm longer than the latter.

Comparative analysis the results in FIG. 9 show that at 6 leaf stage of RxLR121504 protein treated tomato seedlings, the average height of the seedlings was 12.5cm (statistics of 30 seedling heights), while at 6 leaf stage of control CK treated tomato seedlings, the average height of the seedlings was 9.5cm (statistics of 30 seedling heights), the average height of the former was increased by 3cm compared to the average height of the latter. Therefore, the RxLR121504 protein can obviously promote the development and growth of tomato seedling root systems.

Although the invention has been described in detail hereinabove with respect to a general description and specific embodiments thereof, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Sequence listing

<110> Shandong university of agriculture

Application of <120> phytophthora capsici effector factor RxLR121504 in promoting plant growth

<130> PI202010015

<160> 2

<170> SIPOSequenceListing 1.0

<210> 1

<211> 378

<212> DNA

<213> Phytophthora capsici (Phytophthora capsicii)

<400> 1

atgcgcttct cctacgttct tttggctgct gcggctgccc ttctggccac tgccaatgcg 60

atcgaagcgg atcctagaac caggtcgctc cgagcacaca agagtcacga gaaatcccaa 120

gacgaagagc gtgcgttcac ctacactttc aacttcagcc tgtgggacga tcttttcaat 180

tcgcttccgg aacagttcca gcgcatgcgt aaggaacctt ggtacctccg tcggatattc 240

aggagctgga gatcgggcat gggcacgtcg gacgaggcgg tggcgtatat gaggtcccag 300

gggttgagtc agaaagccat tgaccagttc gaggacgcgt acattaagta ccgtgcccac 360

aagctggcaa agggaaaa 378

<210> 2

<211> 126

<212> PRT

<213> Phytophthora capsici (Phytophthora capsicii)

<400> 2

Met Arg Phe Ser Tyr Val Leu Leu Ala Ala Ala Ala Ala Leu Leu Ala

1 5 10 15

Thr Ala Asn Ala Ile Glu Ala Asp Pro Arg Thr Arg Ser Leu Arg Ala

20 25 30

His Lys Ser His Glu Lys Ser Gln Asp Glu Glu Arg Ala Phe Thr Tyr

35 40 45

Thr Phe Asn Phe Ser Leu Trp Asp Asp Leu Phe Asn Ser Leu Pro Glu

50 55 60

Gln Phe Gln Arg Met Arg Lys Glu Pro Trp Tyr Leu Arg Arg Ile Phe

65 70 75 80

Arg Ser Trp Arg Ser Gly Met Gly Thr Ser Asp Glu Ala Val Ala Tyr

85 90 95

Met Arg Ser Gln Gly Leu Ser Gln Lys Ala Ile Asp Gln Phe Glu Asp

100 105 110

Ala Tyr Ile Lys Tyr Arg Ala His Lys Leu Ala Lys Gly Lys

115 120 125

Claims

1. Phytophthora capsici effector factor RxLR121504 and prokaryotic or eukaryotic expression system for expressing Phytophthora capsici effector factor RxLR121504 are applied to promoting plant growth.

2. The use according to claim 1, wherein the phytophthora capsici effector RxLR121504 is formulated as a protein solution, or the escherichia coli bacterial solution or a dilution thereof expressing the phytophthora capsici effector RxLR121504 is applied to the soil around the rhizosphere of plants or a seedling raising substrate.

3. The use as claimed in claim 1, wherein the Phytophthora capsici effector RxLR121504 is formulated into a protein solution, or the strain is subjected to root irrigation treatment with a bacterial solution of Escherichia coli or a dilution thereof expressing the Phytophthora capsici effector RxLR 121504.

4. The use as claimed in claim 1, wherein the Phytophthora capsici effector RxLR121504 is formulated into a protein solution, or a bacterial solution of Escherichia coli expressing the Phytophthora capsici effector RxLR121504 or a diluent thereof is subjected to seed soaking treatment.

5. The use as claimed in claim 1, wherein the gene encoding the Phytophthora capsici effector RxLR121504 is introduced into the plant by a plasmid or integrated into the plant chromosome by genetic engineering means, so that the plant expresses the Phytophthora capsici effector RxLR 121504.

6. The use according to any one of claims 2 to 4, wherein the E.coli expressing the Phytophthora capsici effector RxLR121504 is obtained by introducing the gene encoding the Phytophthora capsici effector RxLR121504 into E.coli competent cells by plasmid.

7. The use according to claim 6, wherein the plasmid is pET28 a; and/or

The Escherichia coli competent cell is DH5 alpha.

8. Use according to claim 1, wherein the plants comprise capsicum, cucumber and tomato.

9. The application of the phytophthora capsici effector RxLR121504 and a prokaryotic or eukaryotic expression system for expressing the phytophthora capsici effector RxLR121504 in the preparation of a plant growth promoter.