CN112980721B

CN112980721B - Bacillus belgii and biocontrol preparation and application thereof

Info

Publication number: CN112980721B
Application number: CN202110129025.1A
Authority: CN
Inventors: 周善跃; 李保华
Original assignee: Qingdao Agricultural University
Current assignee: Qingdao Agricultural University
Priority date: 2021-01-29
Filing date: 2021-01-29
Publication date: 2022-06-10
Anticipated expiration: 2041-01-29
Also published as: CN112980721A

Abstract

The invention discloses a Bacillus belgii strain, a biocontrol preparation and application thereof, wherein the Bacillus belgii strain is named as Bacillus belgii QBB3, is preserved in China center for type culture Collection, and has a preservation number of CCTCC M2021111. The invention also discloses a biocontrol agent, and the active ingredients of the biocontrol agent comprise the thallus, the bacterial liquid, the fermentation filtrate or the active extract of the Bacillus beiLeisi QBB 3. The invention discloses application of Bacillus belgii QBB3 in prevention and treatment of soil-borne phytopathogen diseases. The strain has the effect of preventing and treating various common soil-borne plant disease pathogenic bacteria such as wheat stem-base rot, cucumber fusarium wilt, apple southern blight, phytophthora capsici and the like, can be prepared into a biocontrol agent for preventing and treating important soil-borne diseases such as wheat stem-base rot, cucumber fusarium wilt, apple southern blight and the like, and has good market application prospect.

Description

Bacillus beleisi and biocontrol preparation and application thereof

Technical Field

The invention relates to the technical field of microorganisms, in particular to a bacillus beiLeisi, a biocontrol preparation thereof and application thereof.

Background

Crops are used as a main food source of human life, and human survival is guaranteed, however, after the crops are planted for many years continuously, a large amount of pathogenic bacteria can accumulate in soil to infect roots of the crops, or the pathogenic bacteria invade from the roots to continue to damage overground parts of the crops, so that normal growth of the crops is interfered, the yield of the crops is reduced, the crops can die seriously, and serious economic loss is caused.

For soil-borne diseases of crops, the main prevention and control means at present is still to apply chemical agents. Although the application of chemical agents in preventing and treating plant diseases does have more advantages such as convenient use, quick response, good effect and the like, the use of the chemical agents, particularly the long-term use and unscientific use thereof, can generate a plurality of negative effects such as environmental pollution, damage of soil structures, ecological deterioration, generation of drug resistance of pathogenic bacteria, overproof agricultural product residues and the like, and the negative effects can influence the real life of people. In order to improve or relieve the negative effects of chemical pesticides, the research, development and application promotion of technologies for reducing chemical pesticides and chemical fertilizer application in agricultural production have been started in our country.

The biological biocontrol agent prepared by utilizing antagonistic bacteria is the best substitute of a chemical biocontrol agent, and the biological biocontrol agent not only can effectively prevent and control plant diseases, but also is environment-friendly, ecological and safe and harmless to natural enemies. The biological biocontrol agent has more advantages on the prevention and control of soil-borne diseases. At present, a plurality of biological biocontrol agents are widely applied to the field, such as the prevention and control of agrobacterium tumefaciens by utilizing agrobacterium radiobacter, the prevention and control of trichoderma harzianum to rhizoctonia rot and saprolegniasis, and the like. The biological agent has wide application prospect in agricultural production and has very important significance in ensuring the healthy and sustainable development of agricultural production. However, although there are many varieties of Bacillus belgii strains that have been screened at present, there are few Bacillus belgii strains that satisfy both broad-spectrum and high bactericidal properties.

Therefore, the prior art is in need of further improvement.

Disclosure of Invention

Aiming at the problems, the invention provides a Bacillus beleisi QBB3 with strong inhibitory activity on various important soil-borne plant diseases, a biocontrol agent thereof and application thereof in preventing and treating soil-borne plant pathogenic bacteria diseases, wherein the technical scheme of the invention is as follows:

in a first aspect, the invention provides a strain of Bacillus belgii, named as Bacillus velezensis QBB3, which is preserved in China Center for Type Culture Collection (CCTCC) with the preservation number of M2021111 in 20 days 1 month 2021.

The Bacillus beilesensis QBB3 provided by the invention is separated from the apple tree rhizosphere soil at the test station of Qingdao agricultural university in Laiyang. The bacterial strain forms a colony with irregular edge, wrinkled surface and milky color on an LB culture medium, and the thallus is in a short rod shape through microscopic observation. The sequence of the 16S rDNA of the strain obtained by sequencing is shown as SEQ ID N0:1, the sequence of the gyrA gene is shown as SEQ ID N0:2, and the sequence of the ropB gene is shown as SEQ ID N0: 3. The phylogenetic relationship analysis result identifies that the bacillus is a new bacillus belief.

In a second aspect, the present invention provides a biocontrol agent comprising as an active ingredient the above described Bacillus belgii QBB3, a bacterial solution, a fermentation filtrate or an active extract thereof (e.g., a bacteriostatic substance). The liquid or solid biocontrol agent can be prepared by mixing thallus, bacterial liquid, fermentation filtrate or active extract of Bacillus beiLeisi QBB3 with other adjuvants and adsorbates. The adsorbent comprises one or more of silicon grass soil, activated carbon and grass carbon.

Preferably, in order to further optimize the sterilization effect of the biocontrol agent, the biocontrol agent also comprises other biocontrol bacteria which are complementary with the advantages exerted by the Bacillus beilaisi QBB3, and the bacteriostasis range of the biocontrol agent is further expanded. Or, pesticide can be added to prepare a comprehensive biological control preparation with the insecticidal and bactericidal performance.

In a third aspect, the invention provides an application of the Bacillus beiLeisi QBB3 in prevention and treatment of soil-borne phytopathogen diseases.

Preferably, when the composition is applied, the bacterial liquid or fermentation filtrate or active extract of the Bacillus beiLeisi QBB3 is adopted to treat plants for preventing and treating soil-borne phytopathogen diseases.

Specifically, the soil-borne plant pathogenic bacteria diseases comprise various typical soil-borne plant pathogenic bacteria such as wheat basal stem rot, cucumber fusarium wilt, apple southern blight, pepper phytophthora blight and the like. In the examples, the pathogenic bacteria experiments of several diseases such as wheat stem rot, cucumber fusarium wilt, apple southern blight and pepper phytophthora blight are only exemplified.

The application mode comprises the application of the method in inhibiting conidium germination of soil-borne phytopathogen and inhibiting hypha growth of the soil-borne phytopathogen.

Preferably, the use also includes use in inhibiting germination of fusarium pseudograminearum conidia and fusarium oxysporum conidia. The experimental result shows that when the fermentation liquor and the filtrate of the QBB3 strain are used for treating conidia of fusarium graminearum, fusarium pseudograminearum and fusarium oxysporum, the control conidia germination rate reaches 90%, and the inhibition rates of the conidia germination of the fusarium graminearum, the fusarium pseudograminearum and the fusarium oxysporum are all 100%.

Secondly, the application mode also comprises the application of inhibiting the fusarium graminearum conidium from infecting the wheat coleoptile. Experiments prove that fermentation liquor and filtrate of the QBB3 strain both strongly inhibit the infection of fusarium graminearum on wheat coleoptile. Therefore, the QBB3 strain can comprehensively prevent and control the pathogenic bacteria in multiple aspects of inhibiting germination of fusarium pseudograminearum conidia, inhibiting hypha growth of fusarium pseudograminearum, inhibiting infection of fusarium pseudograminearum on wheat coleoptile and the like.

And thirdly, the QBB3 strain has strong inhibition effect on hyphae of southern apple sclerotium rolfsii, and the inhibition rate of 50% of fermentation liquor of the QBB3 strain on the growth of hyphae of southern sclerotium rolfsii reaches 92.75%.

In a fourth aspect, the invention provides a method for controlling pathogenic bacteria diseases of soil-borne plants, which comprises the following steps: applying the biocontrol formulation described above to plants. The QBB3 strain and the biocontrol agent thereof provided by the invention provide a new method for preventing and treating soil-borne phytopathogen diseases.

The invention has the following beneficial effects:

1. the invention provides a new Bacillus beiLeisi QBB3 with broad-spectrum bactericidal property, which has prevention and treatment effect on various common soil-borne plant disease pathogenic bacteria such as wheat stem-based rot, cucumber fusarium wilt, apple southern blight, phytophthora capsici and the like, can be prepared into a biocontrol agent for preventing and treating important soil-borne diseases such as wheat stem-based rot, cucumber fusarium wilt, apple southern blight, pepper phytophthora blight and the like, and has good market application prospect.

2. The Bacillus belgii QBB3 has diversified inhibiting effects on soil-borne plant disease pathogenic bacteria, is not only reflected in inhibition on growth of pathogenic bacteria hyphae, but also inhibits normal germination of pathogenic bacteria conidia and infection of pathogenic bacteria on wheat coleoptiles, so that more comprehensive prevention and control on the pathogenic bacteria are achieved. In the present application, Fusarium pseudograminearum is described as a representative case.

Drawings

FIG. 1 is a phylogenetic relationship analysis of different genes of QBB3 strain; wherein A is the analysis of the development relationship of the 16SrDNA gene, B is the analysis of the development relationship of the gyrA gene, and C is the analysis of the development relationship of the ropB gene.

FIG. 2 shows the results of a fermentation filtrate from strain QBB3 showing the inhibition of conidium germination of Fusarium pseudograminearum; wherein A is the fermentation filtrate treatment, B is the 10% fermentation filtrate treatment, and C is the 1% fermentation filtrate treatment.

FIG. 3 shows the results of fermentation and filtration of QBB3 strain on Fusarium pseudograminearum infected coleoptile;

FIG. 4 shows the experimental results of the fermentation broth of QBB3 strain on hypha growth of Sclerotinia solanacearum.

FIG. 5 shows the results of experiments on the treatment of Phytophthora capsici mycelia and sporangia with the fermentation filtrate of QBB3 strain.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. In the present invention, the equipment and materials used are commercially available or commonly used in the art, if not specified. The methods in the following examples are conventional in the art unless otherwise specified. The reagents used are commercially available, unless otherwise specified. The quantitative experiments of the examples were carried out in 3 replicates.

Example 1 isolation and characterization of Strain QBB3

First, separation and screening of bacterial strains

The strain is isolated from a soil sample around the root of an apple tree at the test station of Qingdao agricultural university in Laiyang city in 2017 in 8 months.

The screening method comprises the following steps: 10g of the above soil sample was added to 90mL of sterileShaking vigorously in water for 10 min. Diluting the supernatant by stages to obtain 10^-2、10^-3The soil suspension of (1). Dipping 10 with sterile inoculating Loop^-3The soil suspension was streaked on a solid LB medium and cultured at a constant temperature of 28 ℃. After 2 days, single colonies were picked.

II, classifying and identifying strains

1. Morphological identification

The screened bacterial strains form colonies with irregular edges and unsmooth wrinkles on the surface on an LB culture medium, and the colonies are milky white. The thallus is in a short rod shape.

2. Molecular identification

1) Extraction of bacterial genomic DNA

An appropriate amount of QBB3 strain is inoculated into a liquid YEPD culture medium (yeast extract 3 g/L, peptone 10 g/L, glucose 20 g/L), shake-cultured for 24h at 28 ℃, and thalli are collected by centrifugation, and genomic DNA of QBB3 is extracted by using a bacterial genomic DNA extraction kit.

2) Sequencing analysis of 16SrDNA, gyrA and rpoB genes

Respectively designing a primer pair 27f and a primer pair 1492r for amplifying 16SrDNA of the QBB3 strain; designing primers gyrA-f and gyrA-r for amplifying gyrA genes; primers rpoB-f and rpoB-r are designed to amplify the rpoB gene of the bacterial genome, and the sequences of the three pairs of primers are respectively as follows:

27f：5’-AGAGTTTGATCCTGGCTCAG-3’

1492r：5’-TACGGCTACCTTGTTACGACTT-3’

gyrA-f：5’-CAGTCAGGAAATGCGTACGTCCTT-3’

gyrA-r：5’-CAAGGTAATGCTCCAGGCATTGCT-3’

rpoB-f：5’-AGGTCAACTAGTTCAGTATGGAC-3’

rpoB-r：5’-AAGAACCGTAACCGGCAACTT-3’

the PCR reaction system used was as follows:

the PCR reaction procedure was as follows:

PCR products are recovered through gel electrophoresis gel, the three PCR products are respectively subjected to TA cloning, corresponding single colonies are respectively picked and sent to a sequencing company for sequencing, the sequencing result of 16SrDNA of the QBB3 strain is shown as SEQ ID N0:1 in a sequence table, the sequencing result of the gyrA gene is shown as SEQ ID N0:2, and the sequence table sequencing structural member of the ropB gene is shown as SEQ ID N0: 3. Phylogenetic relationship analysis was performed based on the sequencing results of these three genes, and the results are shown in FIG. 1. From the phylogenetic relationship analysis results of the three genes, the QBB3 strain is a new Bacillus belgii (Bacillus velezensis).

Example 2 inhibition experiment of QBB3 Strain against plant soil-borne diseases

First, the inhibition effect of QBB3 strain on the germination of pathogen conidium

1. The experimental method comprises the following steps:

1) preparation of QBB3 fermentation liquor and fermentation filtrate

Single colonies of QBB3 were picked and inoculated into 3ml of liquid YEPD medium and shake-cultured at 28 ℃ and 130rpm for 12 h. Inoculating the cultured bacterial liquid into 20ml YEPD culture medium according to the volume concentration of 2%, and performing shake culture at 28 ℃ and 130rpm for 96h, wherein the obtained bacterial culture is fermentation liquor of QBB 3. Centrifuging the fermentation liquor of QBB3 at 12000rpm at room temperature, and filtering the supernatant of the fermentation liquor by a filter with the diameter of 0.22um to obtain the fermentation filtrate of QBB3 fermentation liquor, wherein the fermentation filtrate does not contain QBB3 bacteria and is only the fermentation product of QBB3 bacteria.

2) Inhibition experiment for conidium germination of three different pathogenic bacteria

Diluting the fermentation liquor and the fermentation filtrate at different concentrations, wherein the specific dilution concentrations are 1%, 10% and 100%, and detecting by adopting a concave glass methodAnd (6) measuring. The method of the concave glass slide method comprises the following steps: 30uL of the fermentation filtrate was added to each sterilized concave glass plate at a concentration of 2X 10, wherein the concentration of conidia of Fusarium graminearum, Fusarium pseudograminearum and Fusarium oxysporum was measured⁵The cells/mL are subjected to moisture-preserving culture at 25 ℃, and a control group is arranged at the same time.

When the conidium germination rate of the control group reaches 90%, detecting the germination rates of the conidia in the fermentation liquor and fermentation filtrate treatment groups with different concentrations, and calculating the inhibition rates of the QBB3 fermentation liquor and the fermentation filtrate thereof on the germination of three different types of conidia, namely fusarium graminearum, fusarium pseudograminearum and fusarium oxysporum.

2. Results and analysis of the experiments

As shown in FIG. 2, Fusarium pseudograminearum conidia could not germinate in the QBB3 fermentation broth and the fermentation filtrate; in 10% of QBB3 fermentation liquor and fermentation filtrate, a small amount of fusarium graminearum conidia germinate, but the germination is abnormal, and expanded spherical cells are formed; in 1% of fermentation broth and fermentation filtrate of QBB3, a large number of Fusarium pseudograminearum conidia germinate, but all germinate abnormally to form expanded spherical cells. The results of the QBB3 fermentation broth and fermentation filtrate on the inhibition of conidia of Fusarium graminearum and Fusarium oxysporum were the same as above.

The experimental results prove that the conidia of the fusarium graminearum, the fusarium graminearum and the fusarium oxysporum cannot normally germinate in the QBB3 fermentation liquor and the fermentation filtrate, namely the inhibition rates of the QBB3 fermentation liquor and the fermentation filtrate on the germination of the conidia of the three pathogenic bacteria are all 100%.

Second, the inhibition effect of QBB3 strain on Fusarium graminearum infection of wheat coleoptile

1. The experimental method comprises the following steps:

1) selecting semen Tritici Aestivi, sterilizing with 75% ethanol, soaking in sterile water for 24 hr, and accelerating germination at 25 deg.C for 3-4 days.

2) Activating the Fusarium pseudograminearum strain on a PDA culture medium, culturing at 25 ℃ for 3-4 days, and beating to obtain a strain cake.

3) Single colonies of QBB3 were picked and inoculated into 3ml of liquid YEPD medium and shake-cultured at 28 ℃ and 130rpm for 12 h. Inoculating the cultured bacterial liquid into 20ml YEPD culture medium according to the volume concentration of 2%, and performing shake culture at 28 ℃ and 130rpm for 96h to obtain fermentation liquor of QBB 3. Centrifuging fermentation broth of QBB3 at 12000rpm, filtering supernatant with 0.22um filter to obtain fermentation filtrate of QBB3

4) When the sheath grows to 1.5-2cm, the sheath is spread in an inoculation tray, and a fungus cake of Fusarium pseudograminearum is taken and placed at the bottom of the sheath.

5) And (3) treatment: after the fungus cakes are well placed, respectively spraying fermentation liquor of QBB3, fermentation filtrate of QBB3 and 600x carbendazim on the inoculated wheat coleoptiles; spraying fermentation liquor of QBB3, fermentation filtrate of QBB3 and 600x carbendazim 24 hours after inoculation. Inoculating the bacteria cake, and spraying YEPD as control. 30 wheat coleoptiles were treated each, and repeated 3 times.

6) After moisture preservation is carried out for 24 hours at the temperature of 25 ℃, the fungus cakes on the wheat coleoptiles are removed, and the moisture preservation and the room temperature treatment are continued.

7) The disease results of wheat coleoptiles were investigated after 4-5 days.

2. Results and analysis of the experiments

As shown in FIG. 3, the control wheat coleoptiles all developed, hyphae were fully distributed on the surface of the coleoptiles, and the coleoptiles treated with the fermentation broth and the fermentation filtrate of QBB3 formed lesions only around the inoculation point, and were able to grow into leaves. The results show that the fermentation liquor and the fermentation filtrate of QBB3 have strong inhibition effect on the wheat coleoptile infected by fusarium graminearum.

Third, QBB3 inhibiting effect of strain on growth of southern apple blight

1. Experimental methods

1) Fermentation broth of QBB3 strain was prepared according to the aforementioned method in example 2.

2) Adding the fermentation liquid into PDA culture medium to prepare multiple PDA plates with fermentation liquid content of 0%, 10%, 20% and 50%.

3) Inoculating the activated sclerotium rolfsii cake to the PDA plate prepared in the previous step, and culturing at 25 ℃.

4) When colonies of southern apple blight bacteria grow over a culture dish on a PDA (personal digital assistant) plate with the QBB3 bacterial liquid content of 0, the diameters of the colonies of southern apple blight bacteria on the PDA plate with QBB3 bacterial liquids of different concentrations are measured, and the inhibition rate is calculated.

The inhibition rate is (control colony radius-treated colony radius)/(control colony radius-cake radius) × 100%.

2. Results and analysis of the experiments

The results are shown in fig. 4, and the growth inhibition rate of the fermentation liquid of QBB3 with the content of 50% on southern apple blight bacteria is 92.75%.

Inhibition effect of QBB3 strain on phytophthora capsici

1. The experimental method comprises the following steps:

1) fermentation filtrate of QBB3 strain was prepared according to the method previously described in example 2.

2) The strain of Phytophthora capsici was activated and inoculated on solid 10% V8 medium (V8 vegetable juice 100 ml/l, calcium carbonate 1 g/l, agar powder 12 g/l) and cultured in the dark at 25 ℃ for 1 week.

3) The bacterial colony of the phytophthora capsici on the V8 culture medium is washed by sterile water, and aerial hyphae of the bacterial colony are washed away.

4) Adding a proper amount of sterile water into the phytophthora capsici plate washed from the mycelia in the step 3), and culturing at 25 ℃.

5) After 12h, the plate surfaces in 4) were rinsed with the appropriate amount of fermentation filtrate of QBB3 strain, and the rinse was collected and incubated at 25 ℃.

6) After 6h, the morphology of phytophthora capsici mycelia and sporangia was observed.

2. Results and analysis of the experiments

As shown in FIG. 5, the fermentation filtrate of QBB3 strain treated the bacterial strain, which showed abnormal morphologies of both mycelium and ascorbyl of Phytophthora capsici; the sporangium is abnormal in form, concentrated in protoplasm and abnormal in cutting and splitting of the protoplasm, so that normal zoospores cannot be formed, and asexual propagation is influenced. Therefore, the fermentation filtrate of the QBB3 strain causes extremely strong damage to both the hyphae and the sporangia of the phytophthora capsici, and the damage rate to the sporangia of the phytophthora capsici reaches 100%.

It should be understood that the technical solutions and concepts of the present invention may be equally replaced or changed by those skilled in the art, and all such changes or substitutions should fall within the protection scope of the appended claims.

Sequence listing

<110> Qingdao agricultural university

<120> Bacillus belgii strain and biocontrol preparation and application thereof

<160> 9

<170> SIPOSequenceListing 1.0

<210> 1

<211> 1447

<212> DNA

<213> 16SrDNA of Bacillus belgii (16SrDNA of Bacillus velezensis)

<400> 1

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ccggggctaa taccggatgg ttgtttgaac cgcatggttc agacataaaa ggtggcttcg 180

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aggcgacgat gcgtagccga cctgagaggg tgatcggcca cactgggact gagacacggc 300

ccagactcct acgggaggca gcagtaggga atcttccgca atggacgaaa gtctgacgga 360

gcaacgccgc gtgagtgatg aaggttttcg gatcgtaaag ctctgttgtt agggaagaac 420

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acgtgccagc agccgcggta atacgtaggt ggcaagcgtt gtccggaatt attgggcgta 540

aagggctcgc aggcggtttc ttaagtctga tgtgaaagcc cccggctcaa ccggggaggg 600

tcattggaaa ctggggaact tgagtgcaga agaggagagt ggaattccac gtgtagcggt 660

gaaatgcgta gagatgtgga ggaacaccag tggcgaaggc gactctctgg tctgtaactg 720

acgctgagga gcgaaagcgt ggggagcgaa caggattaga taccctggta gtccacgccg 780

taaacgatga gtgctaagtg ttagggggtt tccgcccctt agtgctgcag ctaacgcatt 840

aagcactccg cctggggagt acggtcgcaa gactgaaact caaaggaatt gacgggggcc 900

cgcacaagcg gtggagcatg tggtttaatt cgaagcaacg cgaagaacct taccaggtct 960

tgacatcctc tgacaatcct agagatagga cgtccccttc gggggcagag tgacaggtgg 1020

tgcatggttg tcgtcagctc gtgtcgtgag atgttgggtt aagtcccgca acgagcgcaa 1080

cccttgatct tagttgccag cattcagttg ggcactctaa ggtgactgcc ggtgacaaac 1140

cggaggaagg tggggatgac gtcaaatcat catgcccctt atgacctggg ctacacacgt 1200

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gttctcagtt cggatcgcag tctgcaactc gactgcgtga agctggaatc gctagtaatc 1320

gcggatcagc atgccgcggt gaatacgttc ccgggccttg tacacaccgc ccgtcacacc 1380

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tgcttgttga cggacacggc aacttcggtt cggttgacgg cgactcagcg gccgcgatgc 300

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aacctcttct tatcagtggt ttcttgatga gggtcttaga gagatgtttc aagacatatc 120

accaattgag gatttcactg gtaacctctc tctagagttc attgactaca gtttaggaga 180

tcctaagtat cccgttgaag agtcaaaaga acgtgatgtg acttactcag ctccgctaag 240

agtgaaggtt cgtttaatta acaaagaaac tggagaggta aaagaccagg atgtcttcat 300

gggtgatttc cctattatga cagataccgg tacttttatc atcaacggtg cagaacgtgt 360

tatcgtatct cagcttgttc ggtctccaag tgtatatttc agtggtaaag tagacaaaaa 420

cggtaaaaaa ggttttaccg cgactgtcat tccaaaccgt ggcgcatggt tagaatacaa 480

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<213> Synthetic sequence 1492r (Synthetic sequence 1492r)

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<212> DNA

<213> Synthetic sequence gyrA-f

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<210> 7

<211> 24

<212> DNA

<213> Synthetic sequence gyrA-r (Synthetic sequence gyrA-r)

<400> 7

caaggtaatg ctccaggcat tgct 24

<210> 8

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<212> DNA

<213> Synthetic sequence rpoB-f (Synthetic sequence rpoB-f)

<400> 8

aggtcaacta gttcagtatg gac 23

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<212> DNA

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aagaaccgta accggcaact t 21

Claims

1. The Bacillus belgii is characterized by being Bacillus belgii QBB3 with the preservation number of CCTCC NO: M2021111.

2. A biocontrol agent characterized in that an active ingredient comprises the bacterial cell, fermentation broth or fermentation filtrate of Bacillus beijerinckii according to claim 1.

3. The use of bacillus beilesiensis QBB3 of claim 1 for the control of soil-borne phytopathogen diseases; the soil-borne plant pathogenic bacteria are fusarium graminearum, pseudofusarium graminearum, fusarium oxysporum, southern apple sclerotium rolfsii or phytophthora capsici.

4. Use according to claim 3, wherein a fermentation broth or filtrate of Bacillus belgii QBB3 is used.

5. Use of bacillus beijerinckii QBB3 according to claim 1 for inhibiting the germination of conidia of fusarium graminearum, fusarium pseudograminearum and fusarium oxysporum.