A biocontrol bacterium DHR14 for preventing and controlling red root disease of rubber trees and its application

Abstract

The present invention belongs to the field of microbial technology, and specifically relates to a biocontrol bacterium DHR14 for preventing and treating red root disease of rubber trees and its application. The biocontrol bacterium DHR14 for preventing and treating red root disease of rubber trees of the present invention has a broad-spectrum antibacterial activity, has a good antagonistic effect on a variety of pathogens such as red root disease of rubber trees, and is a potential biological agent for preventing and treating red root disease of rubber trees, rice seedling disease, eggplant wilt, etc., and the biocontrol bacterium for red root disease of rubber trees of the present invention also has good ability to produce protease, protease, cellulase, β-glucanase, amylase, siderophore, etc. The biocontrol bacterium DHR14 for preventing and treating red root disease of rubber trees of the present invention has a broad development space, and provides a new candidate strain for the biological control of pathogens such as red root disease of rubber trees, rice sheath blight, and rice seedling disease.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and particularly relates to a biocontrol bacterium DHR14 for preventing and treating red root disease of rubber trees and an application thereof. Background Art

[0002] Rubber tree red root disease is a root disease of rubber trees caused by fungi of the genus Ganoderma. The crown of the diseased plant is sparse, with many dead branches, no terminal buds or uneven buds, and the leaves become smaller, yellow and dull, and some leaves are curled. The diseased roots emit a strong mushroom smell. The wood is wet and rotten, soft and spongy, with a layer of white to dark yellow yuba-like fungal film between the bark and the wood. In the hot and rainy season, sessile basidiocarps grow on the roots on the side of the head of the diseased tree. The upper surface is wrinkled, gray-brown, reddish brown or black-brown, and the lower surface is smooth and gray-white. The pathogen of rubber tree red root disease has a wide host range, and the incubation period of the pathogen in the soil can reach several years. If not handled in time, the mortality rate can reach 100%. At present, the prevention and control measures of this disease mainly rely on chemical control and mechanical excavation. The survey rate of rubber tree red root disease is low. Once the symptoms are found in the aboveground part, it means that the infection is already very serious. Therefore, the mechanical excavation control effect is very poor. As the various problems caused by chemical control become increasingly prominent, people have gradually shifted their research direction to biological control. Therefore, isolating and screening biocontrol bacteria that have a preventive and therapeutic effect on rubber tree red root disease is an urgent problem that needs to be solved, which is of great significance to the sustainable development of the rubber industry. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a biocontrol bacterium DHR14 for preventing and treating red root disease of rubber trees and an application thereof.

[0004] The first aspect of the present invention is to provide a biocontrol bacterium DHR14 for preventing and treating red root disease of rubber trees, named: Bacillus Velezii DHR14 ( Bacillus velezensis DHR14), deposited in China Center for Type Culture Collection (CCTCC) with the deposit number CCTCC NO: M 20241190.

[0005] The second aspect of the present invention is to provide a fermentation broth of the biocontrol bacteria DHR14 for preventing and controlling red root disease of rubber trees as described in the first aspect of the present invention.

[0006] Furthermore, the method for preparing the fermentation broth comprises the following steps: inoculating single colonies of the strain into NB culture medium respectively, and culturing in a shaking incubator at 28° C. and 180 rpm to obtain the fermentation broth.

[0007] The third aspect of the present invention is to provide a preparation containing the biocontrol bacteria DHR14 for preventing and controlling red root disease of rubber trees described in the first aspect of the present invention or the fermentation broth described in the second aspect of the present invention.

[0008] The fourth aspect of the present invention is to provide the biocontrol bacterium DHR14 for preventing and controlling red root disease of rubber trees as described in the first aspect of the present invention, or the fermentation liquid as described in the second aspect of the present invention, or the preparation as described in the third aspect of the present invention for preparing antagonistic rubber tree red root disease bacteria. Ganoderma pseudoferreum Application in preparations.

[0009] The fifth aspect of the present invention is to provide the biocontrol bacterium DHR14 for preventing and controlling red root disease of rubber trees as described in the first aspect of the present invention, or the fermentation liquid as described in the second aspect of the present invention, or the preparation as described in the third aspect of the present invention in the preparation of the biocontrol bacterium DHR14 for preventing and controlling red root disease of rubber trees Ganoderma pseudoferreum Application of preparations to treat diseases caused by it.

[0010] The sixth aspect of the present invention is to provide the biocontrol bacterium DHR14 for controlling red root disease of rubber trees as described in the first aspect of the present invention, or the fermentation liquid as described in the second aspect of the present invention, or the preparation as described in the third aspect of the present invention for preparing antagonistic rice sheath blight fungi. Rhizoctonia solani、 and / or Bakanae oryzae Fusarium moniliforme , and / or Fusarium oxysporum f. Fusarium oxysporum、 and / or Alternaria sinensis Alternaria solan , and / or Gibberella graminearum Fusarium graminearum , and / or Pseudomonas aeruginosa Bipolaris sorokiniana , and / or Phytophthora nicotianae Phytophthora nicotianae , and / or tobacco brown spot pathogen Alternaria alternat、 and / or Bipolaris maydis Bipolaris maydis Application in preparations.

[0011] The seventh aspect of the present invention is to provide the biocontrol bacterium DHR14 for controlling red root disease of rubber trees as described in the first aspect of the present invention, or the fermentation liquid as described in the second aspect of the present invention, or the preparation as described in the third aspect of the present invention in the preparation of controlling rice sheath blight fungi. Rhizoctonia solani、 and / or Bakanae oryzae Fusarium moniliforme , and / or Fusarium oxysporum f. Fusarium oxysporum、 and / or Alternaria sinensis Alternaria solan , and / or Gibberella graminearum Fusarium graminearum , and / or Pseudomonas aeruginosa Bipolaris sorokiniana , and / or Phytophthora nicotianae Phytophthora nicotianae , and / or tobacco brown spot pathogen Alternaria alternat、 and / or Bipolaris maydis Bipolaris maydis Application of preparations for diseases caused by it.

[0012] The eighth aspect of the present invention is to provide the use of the biocontrol bacteria DHR14 for controlling red root disease of rubber trees as described in the first aspect of the present invention in the preparation of a preparation for producing protease, and / or cellulase, and / or β-glucanase, and / or amylase, and / or siderophore.

[0013] The biocontrol bacterium DHR14 for preventing and treating red root disease of rubber trees has a broad-spectrum antibacterial activity and is effective against red root disease bacteria of rubber trees. Ganoderma pseudoferreum、 Rhizoctonia solani Rhizoctonia solani、 Bakanae oryzae Fusarium moniliforme Fusarium wilt Fusarium oxysporum、 Tomato early blight Alternaria solan , Gibberella graminearum Fusarium graminearum , Triticum aestivum Bipolaris sorokiniana , Phytophthora nicotianae Phytophthora nicotianae , Tobacco brown spot pathogen Alternaria alternat、 Bipolaris maydis Bipolaris maydis The present invention has good antagonistic effects and is a potential biological agent for preventing and controlling red root disease of rubber tree, rice seedling blight, eggplant wilt, etc., and the rubber tree red root disease biocontrol bacteria of the present invention also has good ability to produce protease, cellulase, β-glucanase, amylase, siderophore, etc. The rubber tree red root disease biocontrol bacteria DHR14 of the present invention has a broad development space and provides a new candidate strain for the biological control of rubber tree red root disease and rice sheath blight, rice seedling blight and other pathogens. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the result of antagonistic screening of strain DHR14.

[0015] Figure 2 This is the culture status of strain DHR14.

[0016] Figure 3 This is an electron micrograph of strain DHR14.

[0017] Figure 4 For strain DHR14 based 16S rRNA Phylogenetic tree of gene sequence alignment results.

[0018] Figure 5 For strain DHR14 based gyrA Phylogenetic tree of gene sequence alignment results.

[0019] Figure 6 The results of biological characteristics determination of strain DHR14.

[0020] Figure 7 This is the broad-spectrum antibacterial result of strain DHR14.

[0021] The strain DHR14 of the present invention is Bacillus Velez, named: Bacillus Velez DHR14 ( Bacillus velezensisDHR14), deposited in the China Center for Type Culture Collection (CCTCC) on June 11, 2024, with the deposit number CCTCC NO: M 20241190, located at Wuhan University, Wuhan, China. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the accompanying drawings in conjunction with specific embodiments to better understand the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Where the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be obtained commercially.

[0023] The bacterial culture medium used in the following examples is as follows:

[0024] NA solid medium (g / L): 3 g beef extract, 5 g polypeptone, 10 g sucrose, 1 g yeast powder, 15 g agar powder, dissolve in water and make up to 1000 mL, adjust pH to 7.0-7.2, and sterilize by high pressure (121°C, 20 min).

[0025] NB liquid medium (g / L): 3 g beef extract, 5 g polypeptone, 10 g sucrose, 1 g yeast powder, dissolve in water and make up to 1000 mL, adjust pH to 7.0-7.2, and sterilize by high pressure (121°C, 20 min).

[0026] PDA solid culture medium (g / L): 200 g potato, 20 g glucose, 15 g agar, add water to dissolve, and finally make up to 1000 mL, pH 7.0-7.2, and sterilize by high pressure (121°C, 20 min).

[0027] LA medium: tryptone 10 g, sodium chloride 10 g, yeast extract 5 g, agar 18 g, deionized water 1000 ml.

[0028] Skim milk agar medium: 15 g skim milk powder, 15 g agar, 1000 mL distilled water.

[0029] Cellulose Congo red medium: 1 g potassium dihydrogen phosphate, 2 g ammonium sulfate, 0.5 g magnesium sulfate heptahydrate, 2 g CMC-Na, 0.5 g sodium chloride, 0.4 g Congo red, 15 g agar, and 1000 mL distilled water.

[0030] Siderophore assay medium (CAS). First, prepare CAS A solution: 1mmol / L CAS (chrome azurol), 4mmol / L CTMAB (hexadecyltrimethylammonium bromide), 0.1mmol / L FeCl3·6H2O. Then prepare CAS B solution: 0.1mol / L phosphate buffer, pH 7.0, and then prepare CAS C solution: 2g sucrose, 3g acid hydrolyzed casein, 20mL 1mmol / L MgSO4, 1mL 1mmol / L CaCl2, 18-20g agar powder, pH 7.0. Sterilize CAS A solution, B solution, and C solution at 115℃ for 15min respectively. When the temperature drops to about 60℃, add 5mL CAS A solution and 0.5mL CAS B solution to 100mL CAS C test plate and mix well.

[0031] Amylase detection medium: 2 g soluble starch, 10 g beef extract, 10 g glucose, 7 g peptone, 18 g agar, and 1000 mL deionized water.

[0032] β-Glucanase detection medium: casein 5g, yeast extract 2.5g, glucose 1g, agar 18g, 1% CMC, deionized water 1000mL.

[0033] Example 1 Obtaining the biocontrol bacterium DHR14

[0034] 1. Sample source

[0035] On May 6, 2023, in the rubber forest of the third team of the Danzhou Experimental Field of the Rubber Research Institute of the Chinese Academy of Tropical Agricultural Sciences. The lateral roots of the rubber trees were collected by digging the soil surface 10 cm away from the trunk, and 100g of root samples were collected at each point. Three samples were collected from each plot, and the time, location and type of sampling were recorded. The collected samples were stored at 4℃ for bacterial isolation.

[0036] 2. Screening of strains

[0037] The rubber tree samples were rinsed with running water for 30 min, and the surface moisture was wiped dry with sterile gauze. Rinse with sterile water three times in the clean bench, and dry with sterile filter paper. Then the surface was sterilized with 75% ethanol (1 min) and 2% NaClO solution (5 min) in turn. After rinsing with sterile water, the root segments were cut into small pieces of tissue of 1-2 cm using a sterilized scalpel, and inoculated into LA medium in the shape of a "pin". Five groups of experiments were repeated for each medium. The inoculated plates were placed in a constant temperature incubator at 28°C for culture. When obvious colonies were observed on the culture medium, single colonies with different morphologies were inoculated into new culture medium with an inoculation needle or inoculation loop for strain purification. The purified strains were stored at 4°C. At the same time, in order to ensure that the isolated bacteria were endophytes of rubber trees, two control groups were set up. One group used sterilized uncut tree roots to print on the plate; the other group used sterile water from the last rinse to spread on the plate. If no microorganisms grow on the plates of the two control groups, it can be determined that endophytes are obtained.

[0038] The single colonies of the strain were inoculated into NB medium and cultured in a shaker at 28 °C and 180 rpm for 12 h to obtain the fermentation broth. After that, the concentration of the fermentation broth was adjusted to OD 600 =2.0, set aside. Take the rubber tree red root pathogen ( Ganoderma pseudoferreum ) on the PDA medium. When the hyphae have grown all over the plate, use a 5 mm hole puncher to punch out the bacterial block on the plate. Take the bacterial cake, with the hyphae facing down, and inoculate it in the center of a new PDA plate. Use a 5 mm hole puncher to punch holes symmetrically on the left and right of the bacterial cake at equal distances (20 mm). Add 30 ul of the strain fermentation liquid into the hole. At the same time, the plate inoculated with NB medium and rubber tree red root disease bacterial cake was used as the control (CK). Place it in an incubator at 28°C, observe and record the antibacterial results after 7 days of incubation. Relative inhibition rate (%) = (control colony diameter - treatment colony diameter) / (control colony diameter - 5) × 100%. In the formula, the unit of each colony diameter is "mm"; "5" is the initial diameter of the treated colony.

[0039] like Figure 1 As shown in the figure, strain DHR14 showed strong inhibitory activity against the red root pathogen of rubber tree, with a relative inhibition rate of 87.98%, indicating that strain DHR14 had a significant antagonistic effect against the red root pathogen of rubber tree. After streaking culture on LA medium for 2 days, the colonies of strain DHR14 were white, round or oval, with a rough surface and wrinkled edges. Gram-positive bacteria ( Figure 2 ). Electron microscope observation shows that the bacterial cells are short rods or elliptical, with a size of (1~3) μm×(0.5~0.8) μm ( Figure 3 ).

[0040] Example 2 Strain DHR14 16S rRNA Genes and gyrA Gene

[0041] The genomic DNA of strain DHR14 was extracted using the Omega Becterial DNA Kit. 16S rDNA Gene primers: 27F 5'-AGAGTTTGATCCTGGCTCAG-3' and 1492R 5'-TACGGCTACCTTGTTACGACTT-3', were used for PCR amplification and sequencing, and the result is shown in SEQ ID No. 1. DNA Star was used to analyze the sequencing results, and BLAST comparison was performed on the NCBI website to determine the species of closely related bacterial strains. 16S rRNA The gene sequence comparison results are Bacillus cereus The Neighbor-Joining phylogenetic tree constructed with ATCC 14579 (NR 074540.1) as an outbranch is shown in Figure 4 shown.

[0042] Using primers for housekeeping genes of Bacillus velez: GyrA -F 5'-CAGTCAGGAAATGCGTACGTCCTT-3' and GyrA -R 5'-CAAGGTAATGCTCCAGGCATTGCT-3', using the extracted DNA as a template, PCR amplification was performed to obtain the target fragment. The PCR reaction system is:

[0043] Table 1 Ex-Taq polymerase chain reaction system

[0044] Component Volume Template DNA 2 μL -F 1 μL -R 1 μL Ex Taq 25 μL <![CDATA[ddH2O]]> 21 μL

[0045] Reaction conditions: 94℃ pre-denaturation for 10min, 94℃ denaturation for 1min, 55℃ annealing for 1min, 72℃ extension for 1min, 72℃ pre-extension for 10min, 4℃ storage, a total of 30 cycles. The PCR stock solution was sent to Wuhan Tianyi Huayu Gene Technology Co., Ltd. for sequencing. The sequencing results were analyzed using DNA Star and BLAST comparison was performed on the NCBI website to determine the species of closely related bacteria. gyr Gene A is shown in SEQ ID NO. 2. gyrA The gene sequence comparison results are Bacillus mojavensis The Neighbor-Joining phylogenetic tree constructed with DSMZ 9205 (AY212986.1) as an outbranch is shown in Figure 5The results showed that the 16SrRNA gene of strain DHR14 was Bacillus velezensis The similarity is the highest, and it is preliminarily determined to be Bacillus bacteria.

[0046] Based on the above test results, combined with morphology, culture characteristics, biological characteristics, etc., the strain DHR14 was identified as Bacillus Velezii and named: Bacillus Velezii DHR14 ( Bacillus velezensis DHR14), deposited in the China Center for Type Culture Collection (CCTCC) on June 11, 2024, with the deposit number CCTCC NO: M 20241190, located at Wuhan University, Wuhan, China.

[0047] Example 3 Determination of biological characteristics of strain DHR14

[0048] The activity of strain DHR14 in producing extracellular enzymes such as protease, cellulase, β-glucanase, and amylase, as well as secreting siderophore, was determined by plate method.

[0049] (1) Protease assay method: Use a 5mm hole puncher to punch two holes symmetrically at 20mm from the center of a skim milk agar plate. Take 10μL of the fermentation liquid of the strain to be tested that has been cultured with NB for 24 hours and slowly inoculate it into one of the holes. Inoculate NB in ​​the other hole as a control. Place the plate in a 28℃ incubator for 3 days. If a transparent circle can be formed around the colony, the strain can produce protease. Measure and record the diameter of the transparent circle.

[0050] (2) Cellulase assay method: Inoculate strain DHR14 onto CMC plates according to the above method. After placing in a 28°C incubator for 3 days, pour an appropriate amount of Congo red solution (1 mg / mL) onto the plates and let them stand for staining for 15 min. Then rinse with sodium chloride solution (1 mol / L) several times and observe whether there is a yellow halo around the colony. If there is, it indicates that the strain can produce cellulase. Measure and record the diameter of the halo.

[0051] (3) Amylase assay method: Test whether the strain has amylase activity. Inoculate strain DHR14 on starch hydrolysis medium and culture at 28°C for 5-7 days. Add iodine solution that does not contain mycelium around the colony for detection. If a transparent circle is produced, it is positive. Measure and record the diameter of the transparent circle.

[0052] (4) Siderophore determination method: Inoculate DHR14 onto a CAS plate according to the method in (1). After placing it in a 28°C incubator for 3 days, observe whether a light yellow halo appears around the colony. If so, it indicates that the strain can produce siderophore. Measure and record the diameter of the halo.

[0053] (5) Determination of β-glucanase: Inoculate DHR14 onto the glucan detection medium plate according to the method in (1). After placing it in a 28°C incubator for 3 to 4 days, observe whether there is a transparent circle around the colony. If there is, it indicates that the strain can produce β-glucanase. Measure and record the diameter of the halo.

[0054] The results are as follows Figure 6 The strain DHR14 has a strong ability to secrete proteases, with a transparent circle diameter of 36.57 mm, and has strong secretion activities of cellulase (halo diameter 28.45 mm) and β-glucanase (26.98 mm), and has the ability to secrete amylase (15.89 mm) and siderophore (12.36 mm).

[0055] Example 4 Determination of the antagonistic spectrum of strain DHR14

[0056] The single colonies of the strain were inoculated into NB medium and cultured in a shaker at 28 °C and 180 rpm for 12 h to obtain the fermentation broth. After that, the concentration of the fermentation broth was adjusted to OD 600 =2.0, spare.

[0057] The rice sheath blight pathogen was isolated by the filter paper confrontation culture method. Rhizoctonia solani、 Bakanae oryzae Fusarium moniliforme Fusarium wilt Fusarium oxysporum、 Tomato early blight Alternaria solan , Gibberella graminearum Fusarium graminearum , Triticum aestivum Bipolaris sorokiniana , Phytophthora nicotianae Phytophthora nicotianae , Tobacco brown spot pathogen Alternaria alternat、 Bipolaris maydis Bipolaris maydis Cultivate on NA medium respectively. When the hyphae cover the entire plate, use a 5mm aperture puncher to punch out the bacterial blocks on the plate. Take one of the bacterial cakes, with the hyphae facing up, and inoculate it in the center of a new NA plate. Use a 5mm puncher to punch holes symmetrically at equal distances (20 mm) on the left and right of the bacterial cake, and add 30ul of the fermentation liquid of the test strain DHR14 into the holes. The inoculated NA medium and the pathogen cake to be tested were used as the control (CK). Each treatment was repeated 3 times and cultured in a 28 ℃ incubator. After 5 days, the antibacterial phenomenon was observed and recorded. The results are shown in Figure 7 The relative inhibition rates of strain DHR14 against various pathogens are shown in Table 2. Strain DHR14 has good antagonism against these nine pathogenic fungi.

[0058] Table 2 Antibacterial effect of strain DHR14 on eight plant pathogenic fungi

[0059] Pathogens Latin name Relative antibacterial rate (%) Rhizoctonia solani 89.74±11.85ab Bakanae oryzae 67.52±6.32c Fusarium wilt 85.67±9.57b Tomato early blight 88.69±7.56ab Gibberella graminearum 45.87±5.79d Triticum sphaeroides 91.74±10.23a Phytophthora nicotianae 94.83±12.75a Tobacco brown spot pathogen 87.26±9.85b Bipolaris maydis 89.45±6.54ab

[0060] The specific embodiments of the present invention are described in detail above, but they are only examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions made to the invention are also within the scope of the present invention. Therefore, the equalization changes and modifications made without departing from the spirit and scope of the present invention should be included in the scope of the present invention.

Claims

1. A biocontrol bacterium DHR14 for preventing and treating red root disease of rubber trees, characterized in that: Named: Bacillus velez DHR14 ( Bacillus velezensis DHR14), deposited in China Center for Type Culture Collection with the deposit number CCTCC NO: M20241190.

2. The fermentation liquid of the biocontrol bacteria DHR14 for preventing and treating red root disease of rubber tree as claimed in claim 1, characterized in that, The method for preparing the fermentation broth comprises the following steps: inoculating single colonies of the strain into NB culture medium respectively, and culturing in a shaking incubator at 28°C and 180 rpm to obtain the fermentation broth.

3. A preparation, characterized in that: Contains the biocontrol bacteria DHR14 for preventing and controlling red root disease of rubber trees as claimed in claim 1 or the fermentation liquid as claimed in claim 2.

4. The biocontrol bacterium DHR14 for preventing and treating red root disease of rubber tree as claimed in claim 1, or the fermentation liquid as claimed in claim 2, or the preparation as claimed in claim 3 in the preparation of antagonistic red root disease bacteria of rubber tree Ganoderma pseudoferreum Application in preparations.

5. The biocontrol bacterium DHR14 for preventing and treating red root disease of rubber tree as claimed in claim 1, or the fermentation liquid as claimed in claim 2, or the preparation as claimed in claim 3 in the preparation of preventing and treating red root disease of rubber tree Ganoderma pseudoferreum Application of preparations to treat diseases caused by.

6. The biocontrol bacterium DHR14 for preventing and controlling red root disease of rubber trees as claimed in claim 1, or the fermentation liquid as claimed in claim 2, or the preparation as claimed in claim 3 in the preparation of antagonistic rice sheath blight fungi Rhizoctonia solani, and / or Bakanae oryzae Fusarium moniliforme , and / or Fusarium oxysporum f. Fusarium oxysporum, and / or Alternaria sinensis Alternaria solan , and / or Gibberella graminearum Fusarium graminearum , and / or Pseudomonas aeruginosa Bipolaris sorokiniana , and / or Phytophthora nicotianae Phytophthora nicotianae , and / or tobacco brown spot pathogen Alternaria alternat, and / or Bipolaris maydis Bipolaris maydis Application in preparations.

7. The biocontrol bacterium DHR14 for preventing and treating red root disease of rubber trees as claimed in claim 1, or the fermentation liquid as claimed in claim 2, or the preparation as claimed in claim 3 in the preparation of preventing and treating rice sheath blight Rhizoctonia solani, and / or Bakanae oryzae Fusarium moniliforme , and / or Fusarium oxysporum f. Fusarium oxysporum, and / or Alternaria sinensis Alternaria solan , and / or Gibberella graminearum Fusarium graminearum , and / or Pseudomonas aeruginosa Bipolaris sorokiniana , and / or Phytophthora nicotianae Phytophthora nicotianae , and / or tobacco brown spot pathogen Alternaria alternat, and / or Bipolaris maydis Bipolaris maydis Application of preparations for diseases caused by it.

8. Use of the biocontrol bacterium DHR14 for preventing and treating red root disease of rubber trees as claimed in claim 1 in preparing a preparation for producing protease, and / or cellulase, and / or β-glucanase, and / or amylase, and / or siderophore.

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