CN109306336B

CN109306336B - Disease control strain taking quorum sensing signal molecules AHLs as targets and application thereof

Info

Publication number: CN109306336B
Application number: CN201811311103.4A
Authority: CN
Inventors: 陈少华; 郭云帆; 张译尹; 叶田; 单雯艳; 阳芳; 张炼辉
Original assignee: South China Agricultural University
Current assignee: South China Agricultural University
Priority date: 2018-11-06
Filing date: 2018-11-06
Publication date: 2021-08-24
Anticipated expiration: 2038-11-06
Also published as: CN109306336A

Abstract

The invention discloses a disease control strain taking quorum sensing signal molecules AHLs as targets, wherein the strain number is GDMCC 60434. The bacillus cereus has good degradation activity aiming at quorum sensing signal molecules AHLs, has stable and obvious degradation effect, has huge application potential in the aspect of preventing and treating pathogenic bacteria hazards of AHLs mediated diseases, and provides a new way and method for biological prevention and treatment of diseases.

Description

Disease control strain taking quorum sensing signal molecules AHLs as targets and application thereof

Technical Field

The invention relates to a prevention and treatment strain, in particular to a disease prevention and treatment strain taking quorum sensing signal molecules AHLs as targets and application thereof.

Background

In agricultural production, the aims of preventing and controlling pathogenic bacteria efficiently and reducing the loss caused by diseases are always achieved by producers. The Pectobacterium (Pectibacter) is a kind of pathogenic bacteria which are harmful to agricultural production and can secrete various hydrolytic enzymes, such as: pectinase, polygalacturonase, protease, etc. The pectobacterium utilize the hydrolytic enzymes to break the defense system of host plants, destroy the tissue structure of the plants, successfully infect and cause the host plants to have the relevant symptoms of soft rot, and finally cause the yield reduction and even the dead production of relevant crops. No effective control measures are available for this type of pathogenic bacteria.

At present, the prevention and cure measures for pectobacterium at home and abroad are implemented by spraying chemical reagents, such as: chemical pesticides or antibiotics such as benziothiazolinone, thifluzazole, agricultural streptomycin or zhongshengmycin are used for preventing and treating, however, a series of problems such as environmental pollution, damaged ecological balance, enhanced drug resistance of pathogenic bacteria, food safety and the like are caused by the large amount of the chemical pesticides. Therefore, the search for a novel, green, environment-friendly and efficient disease control method is urgent.

Bacteria can synthesize, secrete and sense specific signal molecules, and when the population density of the bacteria reaches a certain threshold value, the concentration of the signal molecules in the environment also reaches a certain level, certain genes of the bacteria begin to express, and behaviors which are reached by certain population levels begin to appear, namely Quorum Sensing (QS). (Fuqua WC, SC Winans, EP Greenberg et al.Quorum sensing in bacteria: the LuxR-LuxI family of cell density-responsive transformed regulation [ J ] J bacteria, 1994,176: 269). Quorum sensing phenomenon widely exists in gram-negative bacteria such as Pectobacterium (Pebacteronium), Pseudomonas aeruginosa (Pseudomonas aeruginosa) and rice-based rot (Dickeya zeae), and participates in regulating some important biological functions, such as synthesis of hydrolase, pyocyanic toxin, etc. Acyl Homoserine Lactones (AHLs) are quorum sensing signal molecules of gram-negative bacteria, and the AHLs include some traditional AHLs such as: n- (3-oxohexanoyl) -L-homoserine lactone (N- (3-oxohexanoyl) -L-homoserine lactone, OHL), N- (3-oxooctanoyl) -L-homoserine lactone (N- (3-oxooctanoyl) -L-homoserine lactone, OOHL), etc., and also include some novel AHLs such as: isovaleryl-homoserine lactone (Isovaleryl-homoserine lactone), carboxylated acyl-homoserine lactones (carboxyl-AHLs), Aryl-homoserine lactone (Aryl-homoserine lactone), and coumaroyl-homoserine lactone (p-coumaroyl-HSL), and the like. Quorum Quenching (QQ) is a way to interfere with Quorum sensing systems by inhibiting the mechanisms by which signal molecules are synthesized, accumulated, monitored, or enzymatically degraded or modified (Fetzner S. Quorum quenching enzymes [ J ]. J Biotechnol,2015,201: 2-14.).

Quorum sensing quenching is a new disease control strategy, pathogenic bacteria can be controlled by the method, the survival pressure of the pathogenic bacteria can not be increased, and the drug resistance of the pathogenic bacteria can be avoided. The new approach has the advantages of simple operation, economy, practicability, environmental friendliness and the like. The development of different quorum sensing quenching preparations is a hot spot in international research at present.

Disclosure of Invention

The invention overcomes the defects of the existing pathogenic bacteria biological control technology, and provides Bacillus cereus capable of efficiently degrading quorum sensing signal molecules AHLs and application thereof in disease control. The bacillus cereus has obvious degradation effect on quorum sensing signal molecules AHLs, has great potential in the aspect of preventing and treating pathogenic bacteria depending on the AHLs, and has great practical significance in solving the problems of abuse of chemical pesticides or antibiotics and drug resistance of the pathogenic bacteria.

In order to achieve the purpose, the invention adopts a technical scheme that:

a disease control strain taking quorum sensing signal molecules AHLs as targets is characterized in that the strain preservation number is GDMCC 60434.

An application of a disease control strain taking quorum sensing signal molecules AHLs as targets in degrading quorum sensing signal molecules AHLs or preparing products of degrading AHLs.

In a preferred embodiment of the present invention, the quorum sensing signal molecules AHLs further include one or more of the following: n- (3-oxohexanoyl) -L-homoserine lactone, N- (3-oxooctanoyl) -L-homoserine lactone, isovaleryl-homoserine lactone, carboxylated acyl-homoserine lactone, aryl-homoserine lactone and coumaroyl-homoserine lactone.

An application of bacillus in preventing and treating the plant diseases caused by AHLs or preparing the preventing and treating agent for the pathogenic bacteria caused by AHLs.

In a preferred embodiment of the present invention, further comprising, the strain is Bacillus cereus strain XN-42.

A method for preventing and treating the pathogenic bacteria depending on AHLs includes inoculating the Bacillus cereus strain XN-42 to crops.

In a preferred embodiment of the present invention, it is further included that said AHLs dependent pathogenic bacteria comprise: the bacillus licheniformis, the pectobacterium and the pseudomonas aeruginosa.

In a preferred embodiment of the invention, the degrading bacteria agent further comprises a bacillus cereus strain XN-42 and a bacillus cereus strain XN-42 bacteria liquid.

A biological control agent for pathogenic bacteria depending on AHLs, which comprises Bacillus cereus strain XN-42 and Bacillus cereus strain XN-42 bacterial liquid.

The strain is obtained by artificial screening, separation and purification from soil collected from farm vegetable lands of agriculture and university in south China, Guangzhou, morphological characteristics and 16S rDNA phylogenetic analysis of the strain, and the strain XN-42 is identified to be Bacillus cereus and named as XN-42.

Is preserved in Guangdong province microorganism culture collection center, and the preservation number is GDMCC NO: 60434.

colony morphology characteristics of Strain XN-42: light yellow, round, convex, opaque, neat edge.

The morphological characteristics of the thalli observed by an electron microscope are as follows: the cells are rod-shaped and have flagella.

The resistance of the strain XN-42 to ampicillin, kanamycin, neomycin sulfate and streptomycin reaches more than 400 mu g/mL, the resistance to gentamicin reaches 150 mu g/mL, the resistance to carbenicillin reaches 350 mu g/mL, the resistance to tetracycline reaches 10 mu g/mL, and the resistance to chloramphenicol reaches less than 5 mu g/mL.

The Bacillus cereus strain XN-42 provided by the invention can effectively degrade quorum sensing signal molecules OHL, can normally grow in a culture medium with the concentration of 0.5mM and with the OHL as the only carbon source, and has a rate of degrading the quorum sensing signal molecules with the initial concentration of 0.5mM within 96h to reach 73%, so that the strain has great application potential in the aspect of preventing and treating AHLs mediated pathogenic bacteria.

Inoculating the crops with the bacterial liquid of the bacillus cereus strain XN-42 to prevent the infection of pathogenic bacteria depending on AHLs.

The most suitable culture medium for preparing the bacterial liquid of the strain XN-42 is Luria-Bertani culture medium, and the formula is as follows: 10.0g/L of tryptone, 5.0g/L of yeast extract, 10.0g/L of sodium chloride, pH 6.8-7.2 and sterilization at 121 ℃ for 20 min.

The invention solves the defects in the background technology, and has the following beneficial effects:

the research of the invention discovers that the bacillus cereus has better degradation activity aiming at quorum sensing signal molecules AHLs, has stable and obvious degradation effect, has huge application potential in the aspect of preventing and treating pathogenic bacteria hazards of AHLs mediated diseases, and provides a new way and a new method for biological prevention and treatment of diseases.

Drawings

The invention is further illustrated with reference to the following figures and examples.

FIG. 1 is a colony morphology of the strain XN-42 of the present invention on LB medium.

FIG. 2 is a scanning electron micrograph of the strain XN-42 of the present invention.

FIG. 3 is a phylogenetic tree analysis diagram of strain XN-42 of the present invention.

FIG. 4 is a graph showing the growth of strain XN-42 of the present invention in various antibiotics.

FIG. 5 is a graph showing the measurement of the degradation activity of strain XN-42 of the present invention on OHL. (CK is blank control without addition of quench sterilization).

FIG. 6A is a control panel of non-inoculated strain XN-42.

FIG. 6B is a high performance liquid chromatogram of strain XN-42 for OHL degradation by 0 d.

FIG. 6C is a high performance liquid chromatogram of strain XN-42 on OHL degradation 1 d.

FIG. 6D is a high performance liquid chromatogram of strain XN-42 on OHL degradation for 2D.

FIG. 6E is a high performance liquid chromatogram of strain XN-42 on OHL degradation for 3 d.

FIG. 6F is a high performance liquid chromatogram of strain XN-42 on OHL degradation 4 d.

FIG. 7 is a graph showing the growth curve and degradation curve of strain XN-42 of the present invention using OHL as a sole carbon source.

FIG. 8 shows the onset of the bacterial strains XN-42, E.coli, B23 of the present invention after being co-inoculated with Z3-3, respectively, into potato tubers for 24 hours.

Fig. 9 shows the disease of strains XN-42, E.coli, B23 of the present invention after being inoculated with Z3-3 together with cabbage stalk for 24 h.

Fig. 10 shows the disease of the strains XN-42, E.coli, B23 of the present invention after being co-inoculated with Z3-3 for 24 h.

Detailed Description

The invention will now be described in further detail with reference to the accompanying drawings and examples, which are simplified schematic drawings and illustrate only the basic structure of the invention in a schematic manner, and thus show only the constituents relevant to the invention.

Unless otherwise specified, reagents and materials used in the examples of the present invention are commercially available.

The media and reagents used in the following examples are as follows:

Luria-Bertani Medium (LB): 10.0g/L of tryptone, 5.0g/L of yeast extract, 10.0g/L of sodium chloride, pH 6.8-7.2 and sterilization at 121 ℃ for 20 min. The LB solid medium was formulated by adding 1.5% (w/v) agar to the liquid medium.

Basal salt medium (MSM): (NH)₄)₂SO₄，2.0g/L；CaCl₂·2H₂O，0.01g/L；Na₂HPO₄·12H₂O，1.5g/L；KH₂PO₄，1.5g/L；MgSO₄·7H₂O，0.2g/L；FeSO₄·7H₂O，0.001g/L；pH 6.5。

Basal medium (MM): k₂HPO₄，10.5g/L；KH₂PO₄，4.5g/L；(NH₄)₂SO₄，2.0g/L；Mannitol，2.0g/L；Glycerol，2.0g/L；MgSO₄·7H₂O，0.2g/L；CaCl₂，0.01g/L；FeSO₄，0.005g/L；MnCl₂，0.002g/L；pH 6.5。

OHL was purchased from Shanghai Yode chemical science and technology, Inc., and X-gal, the reagents required for the culture medium were purchased from Guangzhou Qixiang, Huaqisheng, etc.

Example 1 isolation and screening of Bacillus cereus XN-42

1.1, soil sample collection: soil samples collected from farms in the university of agriculture in south china were used as the microbial source.

Soil samples were collected from farm vegetable fields of southern China agriculture university in Guangzhou, Guangdong in 2017 and 30 months, where they were sampled, bagged and taken back to the laboratory as a microbial source for strain isolation.

1.2, enrichment culture of strains: preparing a basal salt culture medium (MSM), filling 50mL of MSM culture medium into a 250mL triangular flask, sterilizing at 121 ℃ for 20min, cooling, adding OHL mother liquor (the concentration is 100mm/L, the solvent is acetonitrile) under an aseptic condition to ensure that the final concentration of OHL in the culture medium is 5 mu mol/L, then adding 5g of soil sample, placing the mixture in a shaker at 30 ℃ and 200rpm for 7d, and sampling according to the inoculation amount of 10% to transfer the mixture into the MSM culture medium with the OHL concentration of 10 mu mol/L. After culturing for 7 days under the same conditions, samples were taken at an inoculum size of 10% and transferred to MSM medium with an OHL concentration of 20. mu. mol/L, and then cultured for 7 days under the same conditions. By analogy, 7d is a period, and the concentration of OHL is continuously increased to 80 mu mol/L.

1.3, strain separation and purification: the strain is separated and purified by dilution, plate coating and plate drawing.

1mL of the final MSM culture medium was diluted with sterile water to 10 concentrations^-1、10^-2、10^-3、10^-4、10^-5、10^-6、10^-7、10^-8Then, 100. mu.L of each concentration of the culture solution was aspirated, uniformly coated on an LB solid plate, air-dried, and cultured at 30 ℃ for 24 hours. And picking single colonies with different forms growing on the plate, and repeatedly carrying out streak culture and purification on an LB solid plate until a single strain is separated. The strain is preserved by a glycerol conservation method, and degradation activity is detected by further experiments.

1.4, strain screening: the strain having the degrading activity was selected using a reporter strain CF11(Agrobacterium tumefaciens CF 11).

Taking out the strain to be screened from a refrigerator at the temperature of-80 ℃, and scratchingThe line was activated on an LB solid medium plate and cultured in an incubator at 30 ℃ for 24 hours. And (3) selecting a single colony, inoculating the single colony to an LB liquid culture medium, and culturing overnight at the temperature of 30 ℃ and the speed of 200rpm to obtain a bacterial liquid. Take 1 OD₆₀₀The resulting cells were transferred to 1mL of MSM medium with OHL concentration of 20. mu. mol/L, and mixed well to obtain 1mL of a culture medium. The culture medium was transferred to a 2mL centrifuge tube and incubated at 30 ℃ for 24 hours at 200 rpm. After 24h, 5. mu.L of the reaction mixture was spotted onto the top of a 1cm wide MM agar strip, air dried, and then spotted in a row (about 13-18 spots) below to report the bacterial suspension of the strain. Wherein the reporter strain was cultured overnight at 28 ℃ and 200rpm until turbid, and agar strips were obtained by cutting MM plates with an X-gal concentration of 40. mu.g/mL. And placing the agar strips with the samples and the report strains in an incubator at 28 ℃, processing the agar strips in a dark place, and observing an experimental result after the agar strips are placed for 24 hours.

As a result, OHHL has diffusivity, and the diffusion distance is proportional to its concentration. When the reporter strain CF11 senses the presence of OHHL in the environment, its β -galactosidase gene begins to be expressed and releases β -galactosidase into the environment. The colorless compound X-gal (5-bromo-4-chloro-3-indole-beta-D-galactoside) in the MM agar strips can be enzymolyzed into galactose and a dark blue substance 5-bromo-4-indigo, and the colony of the whole reporter strain can be changed into blue by the 5-bromo-4-indigo. That is, the more OHHL contained in the reaction mixture, the longer the distance from the top to blue, and vice versa. And (4) screening the strain with the best OHL degradation effect according to the experimental result, and naming the strain as XN-42.

Example 2 identification of Bacillus cereus Strain XN-42

In this example, morphological characteristics and 16S rDNA phylogenetic analysis were performed on the degrading bacterium XN-42, and the strain was identified as Bacillus cereus. The method comprises the following specific steps:

2.1 colony morphology characteristics: culturing on LB solid plate for 48h, the colony is light yellow, round, convex, opaque and neat in edge, as shown in FIG. 1; the strain showed diffusible turbidity in LB liquid medium, and grew well under aerobic conditions at 30 ℃.

2.2 morphological characteristics of the cells: as shown in FIG. 2, the cells were rod-shaped and had flagella on the surface.

2.316S rDNA sequence and phylogenetic analysis: the length of the 16S rDNA gene sequence of the strain XN-42 is 1436bp, and the strain XN-42 has higher homology (> 99%) with Bacillus cereus after being compared with NCBI database (http:// www.ncbi.nlm.nih.gov /), and the phylogenetic tree is shown in figure 3.

EXAMPLE 3 antibiotic susceptibility analysis of Strain XN-42

In order to better study strain XN-42, this example performed a number of antibiotic susceptibility tests on strain XN-42, the results of which are shown in FIG. 4.

The experimental results show that: the resistance of the strain XN-42 to ampicillin, kanamycin, neomycin sulfate and streptomycin reaches more than 400 mu g/mL, the resistance to gentamicin reaches 150 mu g/mL, the resistance to carbenicillin reaches 350 mu g/mL, the resistance to tetracycline reaches 10 mu g/mL, and the resistance to chloramphenicol reaches less than 5 mu g/mL. This result was used as a reference for the selection of suitable antibiotics for subsequent studies.

Example 4 determination of OHL degrading Activity by Strain XN-42

This example uses a reporter strain CF11(Agrobacterium tumefaciens) to examine the effect of strain XN-42 on OHL degradation.

The strain XN-42 is activated by an LB solid medium plate, and the plate is placed in an incubator at 30 ℃ for 24 hours. A single colony was picked and inoculated into liquid LB medium, and cultured overnight at 30 ℃ and 200rpm to obtain a bacterial solution. Take 1 OD₆₀₀The resulting cells were mixed with 1mL of MSM medium containing OHL as the sole carbon source, and transferred to a 2mL centrifuge tube to obtain a culture medium, wherein the concentration of OHL in the MSM medium was 10. mu. mol/L. Culturing at 30 deg.C and 200rpm for 24 h. After 24h, 5. mu.L of the reaction mixture was spotted onto the top of the agar strips, and then the reporter strain broth was spotted in sequence below, and the reporter strain was cultured as described in example 1. And then placing the agar strips with the reaction mixture and the report strain in an incubator at 28 ℃, carrying out light-shielding treatment, and observing the experimental result after culturing for 24 hours. Wherein the agar strips are obtained by cutting MM plate containing 40 mu g/mL X-gal. CK is a blank without XN-42.

The results of the experiment are shown in fig. 5, where agar bars of the CK experimental group turned blue at approximately 1/2, indicating that the sample contained OHHL; the agar bars of the XN-42 test group did not turn blue, indicating that the sample contained no OHL, i.e., OHL had been completely degraded by XN-42. The results show that: strain XN-42 has OHL degrading activity.

Example 5 Activity of Strain XN-42 for degrading OHL by HPLC

5.1, activating the strain XN-42 frozen at-80 ℃ by using an LB solid plate, culturing at 30 ℃ for 24h, then selecting a single colony on the plate to inoculate in a liquid LB culture medium, and culturing overnight at 30 ℃ and 200rpm to obtain a bacterial liquid. Take 1 OD₆₀₀The cells were resuspended in 1mL of MSM medium, and the resulting suspension was added to 19mL of MSM basal medium, and OHL stock solution (concentration 100mmol/L) was added to the resulting suspension to give a final concentration of 0.2 mmol/L. Culturing at 30 deg.C and 200rpm, sampling at five time points of 0d, 1d, 2d, 3d and 4d, extracting residual OHL in the samples, and determining residual amount of OHL by HPLC to show the degradation of OHL by strain XN-42.

5.2 method for extracting OHL

Taking 7mL of sample into a 15mL centrifuge tube, centrifuging for 10min at the speed of 4000rpm, taking 5mL of supernatant into a 50mL separating funnel, adding equal volume of ethyl acetate into the separating funnel, violently shaking for 3min, standing, layering, transferring the lower layer solution into a graduated glass test tube, and filtering the upper layer extract solution into a 50mL round-bottom flask through a funnel paved with filter paper. The lower layer solution was extracted again as described above. After the filtrate was evaporated to dryness by rotary evaporation, the round-bottomed flask was washed twice with chromatographic acetonitrile and the volume was made up to 2 mL. Finally, the sample is filtered through a 0.45 μm organic filter membrane into a sample bottle, and the residual OHL content is determined by using HPLC.

5.3 HPLC detection conditions for OHL

HPLC instrument model: waters 2695. A chromatographic column: c₁₈Reverse phase chromatography column (250 column (2695 ready for use), flow rate 0.5mL/min, column temperature 30 ℃, mobile phase acetonitrile: water 70; 30 (v: v), detection wavelength 210nm, sample loading 20 μ L.

5.4 degradation rate calculation method

Percent degradation (%) - (1-A)₁/A₀)×100，A₁To degrade residual OHL concentration after bacterial treatment, A₀As a control of residual OHHL concentration after treatment.

5.5 analysis of Experimental results

The HPLC detection results are shown in FIG. 6, wherein FIG. A is a graph showing the comparison of the non-inoculated strain XN-42, FIG. B, C, D, E, F is a graph showing the degradation rate of the strain XN-42 to OHL at 0d, 1d, 2d, 3d and 4d, respectively, the degradation rates reach 0%, 30%, 50%, 64% and 73%, respectively, and the OD of the strain XN-42 at the corresponding time₆₀₀The values were 0.002, 0.547, 0.640, 0.784 and 0.683, respectively. Experiments show that under the condition that OHL exists as a unique carbon source, the strain can degrade the OHL and utilize the OHL for growth.

As can be seen from FIG. 7, the degradation of OHL is positively correlated to the growth of the strain, the strain has no retention period in the presence of OHL, and rapidly enters the logarithmic phase of growth, and the logarithmic phase of the strain growth is within 1d, so that the strain has the fastest degradation rate to OHL.

EXAMPLE 6 biocontrol Effect of Strain XN-42 on Soft rot

In this example, the plant soft rot pathogen, Pectobacterium carotovorum subsp. carotovora (Pcc) Z3-3 was taken as an example to study the biocontrol effect of the strain XN-42 on AHLs-dependent pathogenic bacteria.

Strains XN-42, Z3-3, E.coli and B23 were activated by plating with LB solid medium and cultured at 30 ℃. After 24h, single colonies on the plate are respectively picked, inoculated into a liquid LB culture medium and cultured overnight at the temperature of 30 ℃ and the speed of 200rpm until the OD of the bacterial liquid₆₀₀Is greater than 2.0. Among them, Bacillus thuringiensis subsp.Israelensis B23 is a strain known to have a degrading effect on OHL (Dong Y, Xu J, Li X, et al. AiiA, an enzyme that inactivates the acyl hom oligosaccharide and amino-sensitive signal and enzymes of Erwinia carotovora [ J, J]Proc Natl Acad Sci USA,2000,97(7): 3526-. In a biocontrol experiment, four experimental groups will be set up: z3-3+ LB, Z3-Coli, Z3-3+ B23 and Z3-3+ XN-42. Wherein, the experimental group Z3-3+ LB is a blank control group; coli as a negative control group, and Z3-3+ B23 as a positive control group.

Fresh potatoes, Chinese cabbages and carrots are selected as experimental materials, and the materials are washed with distilled water, wherein the potatoes and the carrots are cut into slices with the thickness of about 0.3cm, and the Chinese cabbage stalks are cut into small rectangles with the thickness of about 6cm multiplied by 4 cm. Respectively mixing the Z3-3 bacterial liquid with bacterial liquid of B23, E.coli and XN-42 and liquid LB culture medium in a certain proportion to ensure that the final work OD of XN-42, E.coli, B23 and Z3-3 is₆₀₀2.0. 2 mu L of the mixed bacterial liquid of each experimental group is respectively inoculated to the center of the treated experimental material. Adding wet cotton, keeping moisture, sealing with preservative film to prevent contamination, and culturing in 28 deg.C incubator for 24 hr.

As shown in FIGS. 8, 9 and 10, in the biocontrol experiments of potato, cabbage and carrot, the disease areas of the experimental groups Z3-3+ LB and Z3-3+ E. coli were larger than those of the experimental groups Z3-3+ B23 and Z3-3+ XN-42, and the disease degree was more serious. That is, the disease symptom of the soft rot disease is obviously reduced when OHL degrading bacteria XN-42 and pathogenic bacteria are inoculated together compared with the disease symptom of the soft rot disease when the pathogenic bacteria are inoculated independently. Experimental results show that the strain XN-42 has obvious biological control effect on potato soft rot, cabbage soft rot and carrot soft rot caused by Pectiobacter carotovorum subsp.

The research of the embodiment discovers that the bacillus cereus has better degradation activity for quorum sensing signal molecules AHLs, has stable and obvious degradation effect, has huge application potential in the aspect of preventing and treating pathogenic bacteria hazards of AHLs mediated diseases, and provides a new way and a new method for biological prevention and treatment of diseases.

In light of the foregoing description of the preferred embodiment of the present invention, it is to be understood that various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. A disease control strain with quorum sensing signal molecules AHLs as targets, wherein the quorum sensing signal molecules AHLs are acyl homoserine lactones, and the strain is bacillus cereus (Bacillus cereus)Bacillus cereus) The strain is deposited as GDMCC NO. 60434.

2. A method for preventing and treating pathogenic bacteria diseases depending on AHLs is characterized in that a bacillus cereus strain is used for carrying out inoculation treatment on crops, and the strain is deposited as GDMCC NO. 60434.

3. A method for the control of pathogenic bacteria that cause AHLs dependence according to claim 2, wherein the pathogenic bacteria that cause AHLs dependence include: the bacillus licheniformis, the pectobacterium and the pseudomonas aeruginosa.

4. The degrading microbial inoculum capable of degrading the quorum sensing signal molecules AHLs is characterized by comprising a bacillus cereus strain and a bacillus cereus strain liquid, wherein the strain preservation number is GDMCC NO. 60434.

5. The biological control agent for pathogenic bacteria depending on AHLs is characterized by comprising a bacillus cereus strain and a bacillus cereus strain liquid, wherein the strain preservation number is GDMCC NO. 60434.