CN101148649B - A kind of Bacillus firmus and its agent and application - Google Patents

Abstract

The invention discloses a Bacillus firmus SAB-1 (Bacilliusfirmus SAB-1), which is preserved in the General Microbiology Center of China Microbiological Culture Collection Management Committee, and the preservation number is: CGMCC No.2100; the invention also discloses the use of Bacillus firmus The microbial bacterial agent prepared by SAB-1, the SAB-1 bacterial strain of the present invention can be used for the prevention and treatment of strawberry powdery mildew, and has the characteristics of high efficiency, wide antibacterial spectrum, simple use, low cost, no environmental pollution and the like.

Description

A kind of Bacillus firmus and its agent and application

technical field

The invention belongs to the field of agricultural microorganisms, and in particular relates to a bacillus firmus, a microbial agent produced by using the bacillus firmus, a preparation method and an application thereof.

Background technique

Strawberry powdery mildew is a major disease in strawberry production. In recent years, the incidence of strawberry powdery mildew has gradually increased, especially in protected strawberry powdery mildew. When it occurs seriously, the rate of diseased leaves is more than 45%, and the rate of diseased fruits is more than 50%, which seriously affects the yield, quality and economic benefits of strawberries. (Yang Lianwei. Yantai Fruit Tree, 2005(3): 15～16). As a result, farmers call strawberry powdery mildew "the cancer of strawberries." Strawberry powdery mildew is caused by strawberry powdery mildew, strawberry powdery mildew is Sphaerotheca aphanis, which belongs to Ascomycota subphylum Erysidiomycetes order Erysiphaceae Sphaerotheca genus, and strawberry powdery mildew belongs to obligate parasites (Peries O S. Mycologia, 1962, 52:380-386). At present, the main method of controlling strawberry powdery mildew is to use disease-resistant varieties and chemical agents. However, under normal circumstances, the quality of disease-resistant varieties is relatively poor; chemical agent control is likely to cause resistance to bacteria, as well as fruit pollution and environmental pollution. In addition, all azole agents that have a better control effect on strawberry powdery mildew Inhibits the growth of strawberries. However, biopesticides have attracted more and more attention due to their strong selectivity, high efficiency, low cost, no environmental pollution, and no harm to humans and animals (Liu Bo et al. Henan Agricultural Sciences, 2007 (2): 20-23), By screening and utilizing beneficial organisms resistant to strawberry powdery mildew and their metabolites, biological control becomes an effective way to control strawberry powdery mildew.

At present, the more effective microorganisms or microbial products of preventing and treating strawberry powdery mildew mainly include: Streptomyces ahygroscopuus var. The natural compound osthole (Zi Fuhui et al. Journal of Laiyang Agricultural College, 2005, 22(3): 189～190 and Yan Qingping. Pesticides, 2005, 44(3): 136～137), Bacillus cereus TS -02 (Chen Chong et al. Anhui Agricultural Sciences, 2007, 35(11): 3298-3300).

People have studied the biocontrol potential of Bacillus for at least 40 years. Field application studies have confirmed the stability of Bacillus biocontrol agents in products, the compatibility with chemical pesticides and the control effect of different plants in different years. Consistency is obviously better than that of non-bacillus and fungal biocontrol bacteria (Monica L E et al. Pest Manag Sci, 2001, 57 (8): 695～706.), Bacillus subtilis (Bacillus subtilis) is the most reported in biological control A kind of antagonistic bacterium, plays a particularly important role in the biological control of plant diseases (He Liyuan. Biological Control Bulletin. 1985, 1 (3): 28 ~ 31. Kong Jian et al. Microbiological Journal, 1992, 32 (6 ): 445-449. Lu Suyun. Beijing Agricultural University Press, 1993), it can produce broad-spectrum antibacterial metabolites, is the dominant microbial population of soil and plant microecology, has strong stress resistance and antibacterial and antibacterial Many excellent natural isolates have been successfully applied to the biological control of plant diseases (Cavaglieri L et al., Research in Microbiology, 2005.156 (5/6): 748-754), but the role of Bacillus firmus in biological control is still unclear. Rarely reported, Zhu Tianhui et al. (Forestry Science, 2007, 43(2): 120～123). Qiao Tianmin et al., Forestry Science and Technology, 2007, 31(1): 28～31)) isolated and purified from pine nursery soil A strain of Bacillus firmus (B. firmus) with antagonistic activity. Therefore, screening for bacillus that has an inhibitory effect on pathogenic bacteria is one of the most effective methods for preventing and controlling related plant diseases. After retrieval, no Bacillus firmus that can be used to prevent and treat strawberry powdery mildew has been found.

Contents of the invention

One of the objectives of the present invention is to provide a Bacillus firmus strain with high-efficiency and broad-spectrum bactericidal activity that can be used for the biological control of strawberry powdery mildew against the problems existing in the prevention and treatment of strawberry powdery mildew.

The second object of the present invention is to provide a microbial agent produced by using Bacillus firmus strains and a preparation method thereof.

The third object of the present invention is to provide the use of the Bacillus firmus strain of the present invention in the prevention and treatment of strawberry powdery mildew.

The present invention is realized through the following technical solutions:

A Bacillus firmus SAB-1 (Bacillius firmus SAB-1) was deposited in the General Microorganism Center of China Committee for the Collection of Microorganisms on July 6, 2007, with the preservation number CGMCC No.2100.

The microbial agent produced by the above-mentioned Bacillus firmus SAB-1 has active ingredients of Bacillus firmus SAB-1 cell and its extracellular metabolites.

The above-mentioned microbial bacterial agent can be a liquid preparation.

The preparation method of above-mentioned microbial inoculum specifically comprises the following steps:

(1) Strain activation: Inoculate the SAB-1 strain preserved at low temperature on the LB plate medium, and cultivate it at 28-32°C for 20-24 hours; then pick a single colony and inoculate it on the LB slant medium, and inoculate Cultivate at 28-32°C for 20-24 hours, then wash the surface of the medium with sterile water, and use the eluate as the inoculum;

(2) Preparation of seed solution: add the inoculation solution prepared in step (1) to the LB liquid medium according to the ratio of 0.05 to 0.5% (volume percentage), and shake and cultivate at 28 to 34° C. for 12 to 16 hours to obtain seeds liquid;

(3) Fermentation culture: the seed solution obtained in step (2) is inserted into the corn flour bean cake powder medium according to the ratio of 1 to 10% (volume percentage), and then at 28 to 34°C, the shaking table speed is 170 to 210rpm. Cultivate under high temperature for 22-25 hours to obtain a liquid preparation of bacterial strain SAB-1;

The components and weight percentages of the corn flour bean cake flour medium are as follows: 2.5% to 3.5% corn flour, 2.5% to 3.5% bean cake flour, 0.4% to 0.6% NaCl, and 0.1% to 0.2% _CaCO3 , KH ₂ PO ₄ 0.01% to 0.03% and MgSO ₄ ·7H ₂ O 0.02% to 0.04%, and the rest is water.

The low temperature mentioned in step (1) of the above preparation method refers to the temperature usually used to preserve the strains, which is known to those skilled in the art based on common knowledge.

The composition of the LB plate medium, LB slant medium or LB liquid medium described in the above-mentioned preparation method step (1) or (2) and the preparation method thereof are all well known to those skilled in the art, and can be prepared according to the usual method preparation.

The preparation method of the above-mentioned corn flour bean cake flour medium is to weigh corn flour, bean cake flour, NaCl, CaCO ₃ , KH ₂ PO ₄ and MgSO ₄ according to weight percentage, mix them, and then add water to the required volume.

The temperature described in step (3) of the above preparation method is preferably 30-32° C., the rotation speed of the shaker is preferably 210 rpm, and the incubation time is preferably 24 hours.

In the above microbial agent, the number of viable bacteria of Bacillus firmus SAB-1 is greater than 5×10 ⁹ cfu/g.

Application of the above bacillus firmus SAB-1 in preventing and treating plant diseases.

The above-mentioned Bacillus firmus SAB-1 is used in the prevention and treatment of strawberry powdery mildew.

The use method of the bacterial agent of the present invention: dilute the above-mentioned microbial bacterial agent with water, then spray the diluted liquid bacterial agent on the leaves, flower buds and fruit surfaces before the peak of strawberry powdery mildew, or spray it on the strawberry field at the same time The ground surface can achieve the purpose of controlling strawberry powdery mildew.

Screening and isolation process of SAB-1 strain:

The SAB-1 strain was isolated from the soil of cotton Verticillium wilt field in Xinjiang by the Institute of Plant Protection, Hebei Academy of Agriculture and Forestry Sciences. In 2003, the Institute of Plant Protection, Hebei Academy of Agriculture and Forestry Sciences collected soil samples from five points in the cotton field of the Xinjiang farm, weighed 10g after mixing and put it into a 250mL sterile triangular flask, added 100mL sterile water, put it on a shaker, and 170r /min shaking for 30min, standing for 2h, take 1mL of supernatant and add 9mL of sterile water to make 10mL10 ^-2 times soil microbial suspension, then dilute the soil suspension to 10 ^-3 , 10 ^-4 , 10 ^-5 , ^10-6 times dilution, 200 μL of microbial suspension at each concentration was applied on PDA, improved PDA, LB and KB medium plates, each concentration was repeated 3 times, and cultured at 28°C for 1d, 3d and 5d, respectively. Isolation and purification of microorganisms. Taking strawberry powdery mildew (Sphaerotheca aphanis) as the target to prevent and control the target disease, the screening of microbial disease control effect was carried out in the greenhouse strawberry planting field. Results A bacterial strain with significant control effect on the target disease was screened out, numbered SAB-1.

Characteristics of the SAB-1 strain:

(1) Morphological characteristics

The cells of the strain SAB-1 were positive for Gram staining, and the cells were rod-shaped. After 8 hours of culture, spores were produced. The spores were middle-grown and oval. On the nutrient agar plate, at the early stage of culture, the colonies are light milky white, pus-like, round, with neat edges, and the colonies are raised in the shape of steamed buns, with a moist surface; at the later stage of culture, the colonies are light milky white, with irregular edges, moist surface, and small folds; Straight line culture on agar slant, in a straight line; static culture in liquid medium, white bacterial film formed on the surface.

(2) 16SrDNA sequence determination

The primers used to amplify bacterial 16S rDNA were: F27: (5'AGAGTTTGATCATGGCTCAG3') and R1492 (5'GGCTACCTTGTTACGACTT'3). The 16S rDNA was amplified and sequenced using the genomic DNA of SAB-1 as a template, and the 16S rDNA sequence of SAB-1 was shown in the sequence table. The obtained 16S rDNA sequence of SAB-1 was homologously compared in Genbank, and its phylogenetic tree was obtained by DNAMAN Version 4.0 analysis based on its 16S rDNA sequence (Fig. 1). Homology comparison results showed that the 16S rDNA homology of strain SAB-1 with Bacillus subtilis and Bacillus licheniformis reached 98% (Fig. 2 and Fig. 3), indicating that SAB-1 strain belongs to Bacillus.

(3) Physiological and biochemical characteristics

The physiological and biochemical properties of the SAB-1 strain were tested. The results (see Table 1) show that the physiological and biochemical characteristics of the SAB-1 bacterial strain have the physiological and biochemical characteristics of Bacillus firmus, indicating that the SAB-1 bacterial strain belongs to a kind of Bacillus firmus.

Bacteria Routine Identification Manual ("Common Identification Methods for General Bacteria", etc.) shows that Bacillus firmus is mobile, aerobic, Gram stain positive, spores are oval or columnar, and the cysts are not enlarged. It can grow in 2%-10% NaCl medium; the growth temperature is 10-45°C, and the optimum growth temperature is 28-31°C. Methyl red reaction was negative, V-P reaction was negative. Citrate cannot be utilized. Contact enzyme reaction was positive and lecithinase was negative. The part physiological and biochemical trait detection result of above SAB-1 bacterial strain is compared with Bacillus subtilis standard bacterial strain, according to " common identification method of general bacteria " (Chinese Academy of Sciences Microbial Bacteria Research Bacterial Classification Group Editing, Science Press, 1978), " Bacillus ") (Cai Miaoying, Zhan Like and other translations, Agricultural Press, 1988) and "Microbiological Taxonomy" (Zhang Jizhong, Shanghai Fudan University Press, 1995) retrieval table to determine the physiological strain SAB-1 The biochemical characters were consistent with those of Bacillus firmus. Combined with the results of 16S rDNA sequence homology analysis, the SAB-1 strain was finally identified as Bacillus firmus.

Table 1 Physiological and biochemical assay results of strain SAB-1

Note: "+" means positive result, "-" means negative result, "ND" means not determined, "d" means 11%-89% strains are positive.

Advantages and beneficial effects that the present invention has: (1) the present invention provides a kind of Bacillus firmus bacterial strain that can efficiently prevent and treat plant diseases such as strawberry powdery mildew, and provides a new biological control method for preventing and treating plant diseases such as strawberry powdery mildew Approach; (2) the biocontrol effect of the present invention is remarkable, and the control effect to strawberry powdery mildew reaches 90.31%～93.42%; (3) the preparation method of the present invention is simple, with low cost, easy to popularize and apply; (4) the present invention is pollution-free, Pollution-free, low residue, friendly to the environment, it plays an important role in improving the quality and output of agricultural products, and at the same time can improve the international competitiveness of my country's agricultural products.

Description of drawings

Figure 1 shows the results of the phylogenetic tree analyzed by DNAMAN 5.2.2 based on the 16S rDNA sequence.

Fig. 2 is the 16S rDNA gene sequence homology comparison result of Bacillus firmus SAB-1 strain and Bacillus subtilis 168 strain (Bacillius subtilis 168). Among them, "-" in the sequences of B. subtilis 168 and B. licheniformis ATCC14580 indicates that they are the same as the corresponding bases of SAB-1, and "g, a, c, t" indicate that they are different from the corresponding bases of SAB-1.

Fig. 3 is the comparison result of 16S rDNA gene sequence homology of Bacillus firmus SAB-1 strain and Bacillus licheniformis strain (B.licheniformisATCC 14580). Among them, "-" in the sequences of B. subtilis 168 and B. licheniformis ATCC14580 indicates that they are the same as the corresponding bases of SAB-1, and "g, a, c, t" indicate that they are different from the corresponding bases of SAB-1.

Detailed ways

The following specific examples are used to further clearly explain the present invention, but do not limit the present invention in any way. The experimental methods in the following examples, unless otherwise specified, are conventional methods; the percentages in the following examples, unless otherwise specified, are all percentages by weight.

Example 1

The preparation of SAB-1 microbial bacterial agent, carries out according to the following steps:

(1) Strain activation: the strain SAB-1 stored at -40°C was activated on LB plate medium (30°C), and a single colony was picked and propagated on LB slant medium (30°C) to obtain Inoculation solution; the components and proportions of LB plate medium and LB slant medium are: 0.5% yeast extract, 1% tryptone, 0.5% NaCl, 1% agar powder; 97% distilled water, pH7.0-7.4;

(2) Preparation of seed solution: put 100mL of LB culture solution into a 250mL Erlenmeyer flask, and sterilize with high-pressure damp heat. After the temperature drops to room temperature, insert the above-mentioned activated SAB- 1 strain inoculum, vibrated culture on a shaker with a rotation speed of 190rpm, and cultivated at 30°C for 24 hours to obtain a seed solution; wherein the components and proportions of the LB liquid medium are: yeast extract 0.5%, tryptone 1% , NaCl 0.5%, distilled water 98%, pH7.0-7.4;

(3) Preparation of corn flour and bean cake flour medium: Prepare according to 3. 0% corn flour, 3.0% bean cake flour, 0.5% NaCl, 0.1% CaCO ₃ , 0.02% KH ₂ PO ₄ and 0.03% MgSO ₄ ·7H ₂ O Medium, then add water to make up 100%, stir and mix to obtain corn flour bean cake powder medium; divide into 500mL triangular flasks, 200mL per bottle; autoclave for 30 minutes, then cool down to 30°C for later use;

(4) Fermentation culture: Inoculate 2 mL of the seed liquid obtained in step (2) into each bottle of corn flour bean cake powder medium obtained in step (3); carry out fermentation culture at a constant temperature of 28 ° C and a rotation speed of 190 rpm;

(5) After 17 hours, take a sample from the triangular flask of step (4) every 30 minutes for microscopic examination, count the number of spores and total thalline in the field of view, and calculate the spore rate; the spore rate can be stopped when it reaches 90% Fermentation and cultivation; the liquid preparation of Bacillus firmus SAB-1 is obtained.

Example 2

This experiment was carried out in the strawberry shed at the New Station of Nonghu Road, Mancheng County, Baoding City, Hebei Province, with two rows per plot, four repetitions, and random block arrangement. During the experiment, powdery mildew occurred moderately on strawberry leaves in the whole shed. The Bacillus firmus SAB-1 bacterial agent prepared in Example 1 was inoculated with a knapsack manual sprayer (diluted with water, containing 10 ⁸ cfu/mL of bacteria); purchased, produced by Syngenta in Switzerland, 1500 times of water dilution spray treatment) and blank control (clear water spray); after the blank control is fully onset, the survey is carried out, and the strawberry powdery mildew grade classification standard and control effect calculation method refer to the "National Standard of the People's Republic of China" Guidelines for Field Efficacy Tests of Pesticides (II) Part 119: Fungicides for the Control of Strawberry Powdery Mildew (GB/T17980.119-2004). And calculate the disease index and prevention effect. The test results (see Table 2) show that the control effect of strawberry powdery mildew after the bacterial agent treatment of Bacillus firmus SAB-1 is significantly higher than that of the blank control and the chemical control, and its control effect reaches 93.42%. Bacillus subtilis strain SAB-1 showed good control effect on strawberry powdery mildew.

Table 2 Effect of Bacillus firmus SAB-1 on strawberry powdery mildew

deal with pretreatment condition index post-treatment condition index Anti-efficacy (%) SAB-1 95.00 5.00 93.42a

deal with pretreatment condition index post-treatment condition index Anti-efficacy (%) Pharmacy CK 95.00 45.00 40.79b Blank CK 50.00 40.00 0.00c

Example 3

This experiment was carried out in Shed 314 of Haolong Green Technology Demonstration Park in Gaobeidian City, Hebei Province, with two rows per plot, four repetitions, and random block arrangement. During the experiment, powdery mildew occurred moderately on strawberry leaves in the whole shed. The Bacillus firmus SAB-1 bacterial agent prepared in Example 1 was inoculated with a knapsack manual sprayer (diluted with water, containing 10 ⁸ cfu/mL of bacteria); purchased, produced by Syngenta in Switzerland, 1500 times of water dilution spray treatment) and blank control (clear water spray); after the blank control is fully onset, the survey is carried out, and the strawberry powdery mildew grade classification standard and control effect calculation method refer to the "National Standard of the People's Republic of China" Guidelines for Field Efficacy Tests of Pesticides (II) Part 119: Fungicides for Control of Strawberry Powdery Mildew (GB/T17980.119-2004). And calculate the incidence rate and control effect. The test results (see Table 3) show that the control effect of strawberry powdery mildew after the bacterial agent treatment of Bacillus firmus SAB-1 is significantly higher than that of the blank control and the chemical control, and its control effect reaches 90.31%. Bacillus subtilis strain SAB-1 showed a good control effect on strawberry powdery mildew.

Table 3 Effect of Bacillus firmus SAB-1 on strawberry powdery mildew

deal with Morbidity before treatment (%) Morbidity after treatment (%) Anti-efficacy (%) SAB-1 70.00 5.00 90.31a Pharmacy CK 75.00 35.00 36.67b Blank CK 95.00 70.00 0.00c

Example 4

This experiment was carried out in Shed 308 of Haolong Green Technology Demonstration Park in Gaobeidian City, Hebei Province, with two rows per plot, four repetitions, and random block arrangement. During the experiment, powdery mildew occurred moderately on the strawberry fruit in the whole shed. The treatment is divided into bacterial suspension and removal of bacterial extracellular metabolites. The bacillus firmus SAB-1 inoculum obtained in Example 1 is diluted (containing thalline 10 ⁸ cfu/mL), then the SAB-1 inoculum dilution is divided into two parts, and one part is used for direct spraying (processed as culture fluid , containing bacteria and metabolites); one part was centrifuged at 5000 rpm for 20 minutes, and the supernatant was the extracellular metabolite of Bacillus firmus SAB-1; the same amount of 0.9% normal saline was used for precipitation Suspended, that is, cell suspension (containing cells 10 ⁸ cfu/mL); use water as a blank control. Result (see table 4) shows, the control effect difference of the nutrient solution (containing thalline and metabolite), extracellular metabolite, thalline suspension treatment of bacillus firmus SAB-1 is not significant, but all is significantly higher than blank control Compared with the pesticides, it shows that the extracellular metabolites of Bacillus firmus SAB-1 and the living bacteria have control effects on strawberry powdery mildew. Therefore, the effective active ingredients of Bacillus firmus SAB-1 for preventing and treating strawberry powdery mildew include the cells of Bacillus firmus SAB-1 and its metabolites.

Table 4 Control effect of Bacillus firmus SAB-1 cells and extracellular metabolites on strawberry powdery mildew

deal with Morbidity before treatment (%) Morbidity after treatment (%) Anti-efficacy (%) SAB-1 culture medium 26.79 5.00 78.37a SAB-1 extracellular metabolites 20.88 8.60 52.25a SAB-1 cell suspension 15.10 5.00 61.63a Pharmacy CK 25.90 18.33 17.98b Blank CK 20.50 17.69 0.00c

sequence listing

<110> Institute of Plant Protection, Hebei Academy of Agriculture and Forestry Sciences

<120> A kind of Bacillus firmus and its agent and application

<160>1

<170>PatentIn version 3.3

<210>1

<211>1016

<212>DNA

<213>Bacillus firmus

<400>1

ccacttctgt caccttcggc ggctggctcc ataaaggtta cctcaccgac ttcgggtgtt 60

acaaactctc gtggtgtgac gggcggtgtg tacaaggccc gggaacgtat tcaccgcggc 120

atgctgatcc gcgattacta gcgattccag cttcacgcag tcgagttgca gactgcgatc 180

cgaactgaga acagatttgt gggattggct taacctcgcg gtctcgctgc cctttgttct 240

gtccattgta gcacgtgtgt agcccaggtc ataaggggca tgatgatttg acgtcatccc 300

caccttcctc cggtttgtca ccggcagtca ccttagagtg cccaactgaa tgctggcaac 360

taagatcaag ggttgcgctc gttgcgggac ttaacccaac atctcacgac acgagctgac 420

gacaaccatg caccacctgt cactctgccc ccgaagggga agccctatct ctaggggtgt 480

cagaggatgt caagacctgg taaggttctt cgcgttgctt cgaattaaac cacatgctcc 540

accgcttgtg cgggcccccg tcaattcctt tgagtttcag tcttgcgacc gtactcccca 600

ggcggagtgc ttaatgcgtt agctgcagca ctaaggggcg gaaaccccct aacacttagc 660

actcatcgtt tacggcgtgg actaccaggg tatctaatcc tgttcgctcc ccacgctttc 720

gctcctcagc gtcagttaca gaccagagag tcgccttcgc cactggtgtt cctccacatc 780

tctacgcatt tcaccgctac acgtggaatt ccactctcct cttctgcact caagttcccc 840

agtttccaat gaccctcccc ggttgagccg ggggctttca catcagactt aagaaccgcc 900

tgcgagccct ttacgcccaa taattccgga caacgcttgc cacctacgta ttaccgcggc 960

tgctggcacg tagttagccg tgctttctgg ttaggtacgt caaggtgccg ccctat 1016

Claims (9)

1. a bacillus firmus SAB-1 (Bacillius firmus SAB-1) is deposited in China Committee for Culture Collection of Microorganisms common micro-organisms center, and deposit number is CGMCC No, 2100.

2. the microbiobacterial agent that utilizes the described bacillus firmus SAB-1 of claim 1 to produce is characterized in that its activeconstituents is bacillus firmus SAB-1 thalline and its born of the same parents' extra-metabolite.

3. according to the described microbiobacterial agent of claim 2, it is characterized in that its described microbial inoculum is a liquid formulation.

4. the preparation method of claim 2 or 3 described microbiobacterial agents comprises the steps:

(1) actication of culture: on the SAB-1 inoculation LB plate culture medium with cryopreservation, and under 28～32 ℃, cultivated 20～24 hours; Picking list colony inoculation is on the LB slant medium then, and cultivates 20～24 hours down at 28～32 ℃, washs media surface with sterilized water again, and its elutriant is as inoculation liquid;

(2) preparation of seed liquor: in the LB liquid nutrient medium, insert the inoculation liquid that step (1) prepares according to 0.05～0.5% volume percent ratio, shake down at 28～34 ℃ and cultivated 12～16 hours, get seed liquor;

(3) fermentation culture: step (2) gained seed liquor is inserted in the Semen Maydis powder soybean cake powder substratum according to 1～10% volume percent ratio, cultivated 22～25 hours under 28～34 ℃, shaking speed are the condition of 170～210rpm then, gained is the liquid preparation of bacterial strain SAB-1;

The component and the weight percent thereof of wherein said Semen Maydis powder soybean cake powder substratum are: Semen Maydis powder 2.5%～3.5%, and soybean cake powder 2.5%～3.5%, NaCl 0.4%～0.6%, CaCO ₃0.1%～0.2%, KH ₂PO ₄0.01%～0.03% and MgSO ₄7H ₂O 0.02%～0.04%, and all the other are water.

5. according to the described preparation method of claim 4, it is characterized in that the described temperature of its step (3) is 30～32 ℃.

6. according to the described preparation method of claim 5, it is characterized in that the described shaking speed of its step (3) is 210rpm.

7. according to the described preparation method of claim 6, it is characterized in that the described incubation time of its step (3) is 24 hours.

8. the application of the described bacillus firmus bacterial strain of claim 1 SAB-1 on controlling plant diseases.

9. the described bacillus firmus bacterial strain of claim 1 SAB-1 uses on the control powdery mildew of strawberry.

Images