A kind of Paenibacillus piloreus strain and its application

Abstract

The present invention belongs to the field of development and utilization of microbial germplasm resources, and specifically relates to a Paenibacillus piloreus strain and its application. The strain provided by the present invention is classified and named Paenibacillus piloreus ( Paenibacillus peoriae )ZJU74, the depository unit is China Center for Type Culture Collection, the deposit number is CCTCC NO:M 20232510, and the deposit date is December 8, 2023. The Paenibacillus piloreus strain provided by the present invention has a control effect of up to 56% to 66% on wheat fusarium rust, can reduce vomitoxin by 69% to 82%, and can simultaneously control fusarium rust, rice blast, soybean blight, citrus black spot, bayberry wilt and other plant pathogenic fungal diseases, and has a wide range of control and good control effect.

Description

Technical Field

[0001] The invention belongs to the field of development and utilization of microbial germplasm resources, and specifically relates to a Paenibacillus piloreus strain and application thereof. Background Art

[0002] As one of the three major grains in the world, wheat provides 20% of the world's population with protein and energy. It is also one of my country's main commercial grains and occupies a large share in the international grain trade. In recent years, due to global warming, lack of highly resistant varieties, large-scale wheat-corn rotation, high-yield varieties planted at high density, and extensive straw return to the field, etc. In addition, when Fusarium infects wheat, it will produce the fungal toxin deoxynivalenol, referred to as vomitoxin (DON). This fungal toxin not only helps Fusarium spread the disease along the wheat spike during the infection of wheat, but also can inhibit protein synthesis by binding to ribosomes, damage the immune and reproductive systems of animals and humans, and cause vomiting, diarrhea, nervous disorders, miscarriage, stillbirth and other health problems.

[0003] At present, the prevention and control of wheat fusarium head blight mainly adopts a comprehensive prevention and control technology that combines chemical control, disease-resistant varieties and cultivation measures. However, due to the lack of disease-resistant varieties, chemical control is still the most common prevention and control method for fusarium head blight. In recent years, the irrational use of drugs such as carbendazim and tebuconazole has led to the gradual increase in the resistance of pathogens, the prevention and control effect of drugs has gradually deteriorated, and the risk of damage to the human body and environmental microecology has increased.

[0004] Biological control has a series of advantages such as low harm to agricultural ecology and long-term effectiveness. Biological agents are ideal alternatives to chemical fungicides. More and more biocontrol strains, especially Paenibacillus, are being discovered and used as biocontrol agents to control wheat fusarium wilt. The biocontrol mechanism of Paenibacillus usually includes the following three aspects: (1) producing secondary metabolites to fight pathogens and pests; (2) improving the host plant microbial community and promoting host nutrition and growth; (3) stimulating plant host defense and producing systemic resistance (induced systemic resistance, ISR). At present, there are few reports on the use of Paenibacillus as a biocontrol agent to simultaneously control plant pathogenic fungal diseases and fungal toxins such as fusarium wilt, soybean blight, citrus black spot, and bayberry wilt. Summary of the invention

[0005] In view of the defects existing in the prior art, the present invention provides a Bacillus pilosula strain and its application. The biocontrol agent prepared by using the strain has the function of preventing and treating wheat fusarium rust, soybean blight, citrus black spot disease and bayberry wilt.

[0006] In a first aspect, the present invention provides a strain of Paenibacillus piloreus, which is named Paenibacillus piloreus ( Paenibacillus peoriae ) ZJU74, the preservation unit is China Center for Type Culture Collection (address: Luojia Mountain, Bayi Road, Wuchang District, Wuhan City, Hubei Province), the preservation number is CCTCC NO: M 20232510, and the preservation date is December 8, 2023.

[0007] Furthermore, the 16S rDNA sequence of the Bacillus pierrei is shown as SEQ ID NO.1.

[0008] The strain of Paenibacillus obtained in the present invention was classified as Paenibacillus pilorioides based on physiological and biochemical characteristics and 16S rDNA analysis. Paenibacillus Peoriae ).

[0009] In a second aspect, the present invention provides a biocontrol agent, wherein the active ingredient of the biocontrol agent is the Paenibacillus pierrei described in claim 1.

[0010] Furthermore, the concentration of the Bacillus piloreus is 1×10 7 ~1×10 8 cfu / mL.

[0011] In a third aspect, the present invention provides a method for preparing the above-mentioned biocontrol agent, comprising the following steps:

[0012] (1) inoculating the Paenibacillus pierrei into a liquid culture medium to obtain a seed solution;

[0013] (2) The obtained seed solution was inoculated into the culture medium for expansion and the concentration of Paenibacillus piloreus in the fermentation broth was adjusted to 1×10 6 ~1×10 7 cfu / mL, and the biocontrol agent is obtained.

[0014] Furthermore, the temperature of the expanded culture is 30° C., the time is 72 hours, and the pH value of the fermentation liquid is stabilized at about 7.2.

[0015] Furthermore, the inoculation amount of the seed solution is 1% of the total volume of the seed solution after inoculation.

[0016] In a fourth aspect, the present invention provides the use of the above-mentioned strain or the above-mentioned biocontrol agent in antagonizing Fusarium graminearum.

[0017] In the plate antagonism experiment, the average inhibition distance of ZJU74 strain on Fusarium graminearum can reach 1.86 cm (±0.09), and the sterile supernatant of ZJU74 strain biocontrol agent can also effectively inhibit mycelial growth.

[0018] In a fifth aspect, the present invention provides the use of the above-mentioned strain in preventing and controlling wheat fusarium rust and reducing the production of vomitoxin.

[0019] In a sixth aspect, the present invention provides the use of the above-mentioned biocontrol agent in preventing and controlling wheat fusarium rust and reducing the production of vomitoxin.

[0020] Furthermore, the application method is: at the wheat heading stage or the early flowering stage, the biocontrol agent is evenly sprayed on the wheat ears.

[0021] The ZJU74 strain can significantly inhibit the growth and pathogenicity of Fusarium graminearum PH-1 in two types of wheat, Luyuan 502 and Jimai 44, with the field control effects reaching 66.65% and 56.28% respectively; and it can reduce the vomitoxin by 81.94% and 69.22% respectively, with a good control effect.

[0022] In a seventh aspect, the present invention provides the use of the above-mentioned strain or the above-mentioned biocontrol agent in preventing and controlling soybean blight, citrus black spot disease, and bayberry wilt disease.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The Paenibacillus pierreii strain provided by the present invention has a control effect of up to 56% to 66% on wheat fusarium rust, can reduce vomitoxin by 69% to 82%, and can simultaneously control fusarium rust, rice blast, soybean blight, citrus black spot, bayberry wilt and other plant pathogenic fungal diseases, and has a wider control range and better control effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 These are the colony morphology diagram of the biocontrol bacteria ZJU74 in Example 1 and the antagonistic effect diagram on Fusarium graminearum PH-1; wherein A is the colony morphology diagram of the biocontrol bacteria ZJU74 on the culture medium, and B is the antagonistic effect diagram of the biocontrol bacteria ZJU74 on Fusarium graminearum PH-1.

[0026] Figure 2 The EC50 determination result of the ZJU74 strain inhibiting the growth of Fusarium graminearum hyphae in Example 3 is shown in Figure 3; wherein A is a state diagram of the PH-1 hyphae on the blank control plate when they are fully grown, B is a size state diagram of the PH-1 colonies in each gradient biocontrol bacteria plate, C is a fitting curve of the correlation between the bacterial content of the plate and the inhibition rate, and the horizontal axis is the ZJU74 strain concentration Log 10 CFU / mL, the vertical axis is the diameter of PH-1 colony (cm), R 2 Indicates the degree of fit between the estimated value of the trend line and the corresponding actual data.

[0027] Figure 3This is a graph showing the inhibitory effect of the sterile supernatant of the biocontrol agent prepared by the biocontrol strain ZJU74 in Example 3 on the spores of Fusarium graminearum PH-1.

[0028] Figure 4 These are diagrams showing the antagonistic effects of the biocontrol bacteria ZJU74 on different strains in Example 4; wherein, A is a diagram showing the antagonistic effects of the biocontrol bacteria ZJU74 on rice blast pathogen; B is a diagram showing the antagonistic effects of the biocontrol bacteria ZJU74 on soybean blight pathogen; C is a diagram showing the antagonistic effects of the biocontrol bacteria ZJU74 on citrus black spot pathogen; and D is a diagram showing the antagonistic effects of the biocontrol bacteria ZJU74 on bayberry wilt pathogen.

[0029] Figure 5 These are the control effects of the biocontrol strain ZJU74 on wheat fusarium rust in the field of Luyuan 502 and Jimai 44 in Example 5; wherein, A is the control effect of the biocontrol strain ZJU74 on wheat fusarium rust in the field of Luyuan 502; and B is the control effect of the biocontrol strain ZJU74 on wheat fusarium rust in the field of Jimai 44. DETAILED DESCRIPTION

[0030] In order to make those skilled in the art better understand the scheme of the present invention, the technical scheme of the present invention is clearly and completely described below in conjunction with specific embodiments. It should be noted that the following detailed descriptions are all exemplary and are only embodiments of a part of the present invention, rather than all embodiments.

[0031] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work should fall within the scope of protection of the present invention.

[0032] Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those of ordinary skill in the art to which this application belongs. The experimental materials used in the examples of the present invention are all conventional experimental materials in the art and can be purchased through commercial channels. Experimental methods without specifying detailed conditions were performed according to conventional experimental methods or according to the operating instructions recommended by the supplier.

[0033] The 16S rDNA sequence of Paenibacillus pierrei provided in the following examples is shown as SEQ ID NO.1.

[0034] SEQ ID NO.1:

[0035]

[0036] EC50, half effective concentration, generally refers to the concentration of a drug or compound required to produce half the maximum effect on an organism. In the following examples, it specifically refers to the strain concentration at which the inhibition rate of the ZJU74 strain on the hyphae of Fusarium graminearum reaches 50%.

[0037] Deoxynivalenol, also known as deoxynivalenol and deoxyfusarium wilt alcohol, has a chemical name of 3 α , 7 α , 15-trihydroxy-12,13-epoxytrichothecene-9-anthracen-8-one, belongs to the trichothecene family of compounds.

[0038] The culture medium and culture fluid involved in the following embodiments include:

[0039] R2A medium formula: yeast extract 0.5 g / L, peptone 0.5 g / L, glucose 0.5 g / L, soluble starch 0.5 g / L, potassium dihydrogen phosphate 0.3 g / L, magnesium sulfate 0.04 g / L, sodium pyruvate 0.3 g / L, agar 15 g / L;

[0040] 10% TSA medium formula: 1.5 g / L tryptone, 0.5 g / L soy peptone, 0.5 g / L sodium chloride, and 15 g / L agar.

[0041] LB medium formula: tryptone 10g / L, yeast extract 5g / L, sodium chloride 10g / L, adjust the pH to 7.2.

[0042] LBGM medium formula: tryptone 10g / L, yeast extract 5g / L, sodium chloride 10g / L, 50% glycerol 20 ml / L, 1.51×10 -2 g / L MnSO4, adjust pH to 7.2.

[0043] WA solid plate formula: peptone 5 g / L, glucose 10 g / L, beef extract 3 g / L, sodium chloride 5 g / L, agar powder 15 g / L, pH=7.0.

[0044] PDA medium formula: potato 200 g / L, glucose 20 g / L, agar powder 10 g / L, natural pH.

[0045] CMC liquid culture medium formula: sodium carboxymethyl cellulose 15 g / L, yeast extract 1 g / L, ammonium nitrate 1 g / L, potassium dihydrogen phosphate 1 g / L, magnesium sulfate heptahydrate 0.5 g / L.

[0046] Example 1 Acquisition of ZJU74 strain

[0047] 1. Isolation of culturable Bacillus

[0048] 1 g of diseased tissue with ascocarps was cut from the diseased part of wheat straw and ground in a sterile mortar. The residue obtained after grinding was added to a sterilized 50 mL centrifuge tube, and 10 mL of sterile water was added to resuspend it using a vortex oscillator. The sample was fully mixed under the condition of a shaker at 180 rpm for 30 min. 100 μL of the suspension was drawn into a 1.5 mL sterile EP tube, and 900 μL of sterile water was added to make a 10 -1 Dilution: Follow the same steps to dilute to 10 -2 , 10 -3 , 10 -4 , 10 -5 Dilutions of concentration gradients. Take 100 μL of dilutions in each gradient and evenly spread them on R2A and 10% TSA plates for bacterial isolation (to inhibit fungal growth, carbendazim or tebuconazole with a final concentration of 5 ppm can be added to the plate). Place the plate in a 30°C constant temperature incubator and take out the plate after 1d, 3d, and 5d to observe whether colonies have grown. Pick single Bacillus colonies of different shapes, sizes, and colors and place them on new R2A and TSA plates for purification. Pick purified strains the size of toothpick heads and culture them overnight in LB medium to obtain the corresponding seed solution. Take 900 μL of seed solution and add 50% glycerol at a ratio of 1:1, and store at -80°C to complete the preservation of the strain. Finally, classify and number the samples according to the collection location.

[0049] 2. Antagonistic activity assay of strains against Fusarium graminearum

[0050] The antagonistic activity of Paenibacillus strains against Fusarium graminearum was determined by plate confrontation culture method. First, a toothpick-sized Paenibacillus colony was picked from the activated bacterial plate and two parallel lines were drawn on the left and right sides of the WA solid plate (3 cm from the center of the plate), and cultured in a 30°C incubator for 24 hours. The Fusarium graminearum PH-1 stored at 4°C was inoculated on the PDA plate for activation. After the fungus grew all over the plate, a sterilized punch was used to evenly punch a circular fungus disc with a diameter of 6 mm from the outer edge of the colony, with the mycelium facing down, and the fungus disc was inoculated in the center of the WA plate and placed in a 25°C incubator for culture. The WA plate with Fusarium graminearum in the center of the plate was used as a blank control. When the edge of the control colony was about to expand to the entire plate, the antagonistic distance of Paenibacillus was measured and photographed and recorded. Each treatment was repeated 3 times.

[0051] Method for determining the plate antagonistic distance: measure the vertical distances from the left and right sides and the middle part of the Fusarium graminearum colony to the Bacillus strain at the edge of the WA plate (the antagonistic distances on both sides must be measured, a total of 6 values), and calculate the average antagonistic distance based on the results.

[0052] The antagonistic activity of Paenibacillus strains against Fusarium graminearum was evaluated according to the size of the antagonistic distance: 0 cm, no antagonism; 0-0.5 cm, slight antagonism; 0.5-1.5 cm, moderate antagonism; >1.5 cm, strong antagonism. The Paenibacillus strain ZJU74 with strong antagonism was screened and the test results were as follows: Figure 1 As shown in B. Figure 1 B shows that strain ZJU74 has a strong inhibitory effect on the growth of Fusarium graminearum colonies, with an antagonistic distance of 1.86 cm, and the antagonistic effect is more significant.

[0053] 3. Morphological observation and classification confirmation of ZJU74 strain

[0054] Paenibacillus pilorioides ZJU74 is Gram-positive, with straight rod-shaped cells that can move using peritrichous flagella and produce oval spores in the swollen sporangium. After culturing on LB medium for 24 hours, 1.5 mm colonies can be formed. Figure 1 A, white and viscous, with a moist and smooth surface, easy to pick up, and neat edges. Its 16S rDNA sequence is shown in SEQ ID NO.1, and the comparison results in NCBI show that it is Paenibacillus piloriformis ( Paenibacillus Peoriae ).

[0055] Example 2 Preparation of biocontrol agents

[0056] The ZJU74 strain was inoculated into LB liquid culture medium, and cultured at 30°C and 180 rpm for 20-24 hours. Then, samples were taken in a clean bench to measure the OD value at 600 nm. During the measurement, the culture medium without bacteria was used as a blank control.

[0057] When cultured to OD 600 When the pH value was between 0.5 and 0.8, the seed bacterial solution was added into a 500 mL glass bottle containing fermentation medium (LBGM medium) at a volume ratio of 1:1000, and cultured at 30°C and 180 rpm for 72 h to obtain the fermentation liquid of ZJU74 strain. The pH value of the fermentation liquid was stabilized at 7.2. The gradient dilution plate was tested and the concentration of the bacterial suspension was adjusted to 1×10 7 ~10 8 cfu / mL, and obtain the biocontrol agent.

[0058] Example 3 Antagonism of ZJU74 strain against Fusarium graminearum

[0059] 1. EC50 of ZJU74 strain inhibiting the growth of Fusarium graminearum hyphae

[0060] Add the gradient dilution of ZJU74 strain to the WA medium cooled to 40-50℃, so that the final concentration of ZJU74 is 10 7 cfu / mL, 10 6 cfu / mL, 10 5 cfu / mL, 10 4 cfu / mL, 10 3 cfu / mL, 10 2 cfu / mL, WA plates containing biocontrol bacteria ZJU74 were prepared, and WA plates without biocontrol bacteria were used as blank controls.

[0061] Inoculate the PH-1 bacterial disc of Fusarium graminearum in the center of the plate and culture at 25°C until the mycelium on the blank control plate is fully grown (such as Figure 2 A) and analyze the statistical data, and measure the size of PH-1 colonies on the plates containing each gradient of biocontrol bacteria (such as Figure 2 The half-maximal effect concentration (EC50) was calculated.

[0062] The results are as follows Figure 2 As shown in Figure C, as the bacterial content in the plate increases, the inhibition rate of PH-1 mycelium increases accordingly. Statistical results show that there is a linear relationship between the bacterial content in the plate and the inhibition rate:

[0063] y = -0.6525x + 4.9671 (R² = 0.902) (1);

[0064] Where x is the concentration of ZJU74 strain Log 10 CFU / mL, Y is the diameter of PH-1 colony (cm), R 2 Indicates the degree of fit between the estimated value of the trend line and the corresponding actual data.

[0065] According to formula (1), when the amount of ZJU74 bacteria in the plate is about 10 4 CFU / mL, it can inhibit the growth of Fusarium graminearum hyphae by 50%, that is, the EC50 of ZJU74 against Fusarium graminearum is 10 4 CFU / mL.

[0066] 2. The activity of sterile supernatant of ZJU74 biocontrol agent in inhibiting mycelial growth and spore germination of Fusarium graminearum

[0067] The fermentation liquid of the biocontrol bacteria ZJU74 strain obtained in Example 2 was centrifuged at 10,000 rpm for 20 min, and the sterile supernatant was collected. The sterile supernatant was filtered through a bacterial filter (0.22 μm) and then used.

[0068] Punch 5 bacterial discs at the edge of the colony of Fusarium graminearum PH-1 with a 1 cm borer, add them into a conical flask containing 100 mL CMC culture medium, and culture them at 25 °C and 180 rpm for 5 days; filter the mycelium through 3 layers of sterile filter paper after shaking the crude spore liquid obtained by shaking, centrifuge at 6000 rpm for 10 min, remove the CMC culture medium, and obtain the spore precipitate of Fusarium graminearum. Resuspend the spore precipitate with the same volume of ddH2O, mix it by blowing, and take 10 μL to count it under a hemocytometer, and record the spore concentration (concentration is 10 6 It is best to store it in a 4℃ refrigerator for later use.

[0069] The inhibitory effect of the supernatant of the biocontrol agent on the spores of Fusarium graminearum was tested by the agar punch method: the obtained spore liquid of Fusarium graminearum was diluted with 10 4 cfu / mL was added to the PDA medium melted to 37℃~40℃ (to prevent bacterial contamination, kanamycin with a final concentration of 50ppm was added to the melted medium) and mixed thoroughly. The mixed PDA medium was then poured into a culture dish with a diameter of 6cm to obtain a PDA plate containing spores. A hole was punched in the center of the plate with a hole puncher with a pore diameter of 8mm, and the bottom was sealed with melted PDA medium. After being fully dried, 300μL of sterile supernatant of the biocontrol agent was added. After culturing at 25℃ for 36h, the diameter of the inhibition zone was measured and photographed and recorded ( Figure 3 ), indicating that the sterile supernatant could effectively inhibit mycelial growth.

[0070] Example 4 Determination of the antagonistic activity of ZJU74 strain against other plant pathogens

[0071] The same method as the plate antagonistic activity test on Fusarium graminearum in Example 1 was used to test the antagonistic activity of ZJU74 strain against pathogenic fungi that cause rice blast, soybean blight, citrus black spot disease, and bayberry wilt. The test results are shown in Figure 4 A~D. Figure 4 As shown in A~D, the ZJU74 strain has a good antagonistic effect on pathogenic fungi that cause rice blast, soybean blight, citrus black spot disease, and bayberry wilt.

[0072] Example 5 Field control effect of strain ZJU74 on wheat fusarium head blight and its produced vomitoxin

[0073] 1. Evaluation of the effect of ZJU74 on controlling wheat fusarium head blight in the field

[0074] The field control experiment was conducted in Hefei, Anhui (Anhui Agricultural University Teaching Demonstration Base) and Jinan, Shandong (Shandong Academy of Agricultural Sciences Experimental Base) from April to June 2023. The wheat in the field grew well and the soil water and fertilizer conditions were moderate. The wheat varieties tested were Luyuan 502 and Jimai 44, and the experimental plot area was 10m2 Three experimental plots (three replicates) were set up for each treatment and randomly arranged in the field. The first biocontrol agent treatment (500 mL + 1.5 L water) was carried out when the wheat in the field was at 25% flowering stage, and fluopicolide and clean water were sprayed at the same time.

[0075] The application concentration of ZJU74 biocontrol agent is 10 7 ~10 8 cfu / mL, the dosage is 3L / 667m 2 The dosage of fluopicolide is 60 mL / 667 m 2 .

[0076] The first biocontrol agent was sprayed 48 hours after treatment with a concentration of 1×10 5 cfu / mL of Fusarium graminearum spores, and the second treatment with biocontrol agents was carried out 48 hours later.

[0077] After the wheat scab disease in the field stabilized and the wheat matured, a disease survey was conducted on all treatment plots. During the survey, five sampling points were selected in each treatment area of ​​the experimental field, with 100 ears at each point, for a total of 500 ears. The disease index of each treatment was recorded. The disease of some sampled ears was as follows: Figure 5 Based on the experimental results of the two sites, the biocontrol strain ZJU74 used in the field trial was statistically analyzed and evaluated (as shown in Tables 1 and 2).

[0078] According to the proportion of diseased spikelets with ear rot (or white ear symptoms caused by stalk rot) to all spikelets, the disease condition is divided into 5 levels (level 0: no disease; level 1: the number of diseased spikelets is less than 1 / 4 of all spikelets; level 2: the number of diseased spikelets is 1 / 4~1 / 2 of all spikelets; level 3: the number of diseased spikelets is 1 / 2~3 / 4 of all spikelets; level 4: the number of diseased spikelets is more than 3 / 4 of all spikelets).

[0079] According to the above statistical results, the disease index of each treatment is calculated according to formula (2):

[0080] (2).

[0081] In formula (2): I —disease index; h i —Number of diseased ears corresponding to each severity level; i—value of each level of disease severity; H—total number of ears surveyed.

[0082] Table 1 Evaluation of the effect of each treatment group on the control of wheat scab in the field (Hefei, Anhui)

[0083]

[0084] Table 2 Evaluation of the effect of each treatment group on the control of wheat scab in the field (Jinan, Shandong)

[0085]

[0086] 2. Evaluation of the effect of ZJU74 strain in inhibiting the production of wheat gibberellic virus in the field

[0087] In the above experiment, after the wheat disease was stable and mature, wheat grains were collected in each treatment area according to the 5-point sampling method, with 20 ears per point, totaling 100 ears. The ears were separated and collected in the field and brought back to the laboratory for determination of DON content.

[0088] Grind the wheat grains into powder with a grinder, weigh 1 g of wheat flour and place it in a 50 mL centrifuge tube, add 4 times the volume of acetonitrile: water (84:16, v:v), leave it at room temperature for 6 h, filter it with three layers of lens paper, add an equal volume of ethyl acetate to the filtrate, vortex mix, and completely evaporate the solution on a nitrogen blower. Add 5 ml of acetonitrile: water (84:16, v:v) to dissolve, and then use PuriTox SR The vomitoxin was purified by HPLC-MS (Table 3 and Table 4).

[0089] Table 3 Evaluation of the effect of each treatment group on inhibiting the production of wheat fusarium virus in the field (Hefei, Anhui)

[0090]

[0091] Table 4 Evaluation of the effect of each treatment group on inhibiting the production of wheat fusarium virus in the field (Jinan, Shandong)

[0092]

[0093] It can be seen from Tables 1 and 2 that the field control effect of ZJU74 biocontrol agent on wheat fusarium rust is maintained above 56%; it can be seen from Tables 3 and 4 that ZJU74 biocontrol agent can significantly inhibit the production of vomitoxin of wheat fusarium rust, with the highest inhibition effect reaching 81%, showing good application prospects.

Claims

1. A strain of Paenibacillus pilosula, characterized in that The classification name is Paenibacillus pilorioides ( Paenibacillus peoriae ) ZJU74, the preservation unit is China Center for Type Culture Collection, the preservation number is CCTCCNO: M 20232510, and the preservation date is December 8, 2023.

2. A biocontrol agent, characterized in that: The active ingredient of the biocontrol agent is the Paenibacillus pilosula described in claim 1.

3. The biocontrol agent according to claim 2, characterized in that The concentration of Paenibacillus piloreus is 1×10 7 ~1×10 8 cfu / mL.

4. The method for preparing the biocontrol agent according to any one of claims 2 or 3, characterized in that: The following steps are involved: (1) inoculating the Paenibacillus pierrei into a liquid culture medium to obtain a seed solution; (2) The obtained seed solution was inoculated into the culture medium for expansion and the concentration of Paenibacillus pilosula in the fermentation broth was adjusted to 1×10 6 ~1×10 7 cfu / mL, and the biocontrol agent is obtained.

5. The preparation method according to claim 4, characterized in that: The inoculation amount of the seed solution is 1% of the total volume of the seed solution after inoculation.

6. Use of the strain according to claim 1 or the biocontrol agent according to any one of claims 2 to 3 in antagonizing Fusarium graminearum.

7. Use of the strain as claimed in claim 1 in preventing and controlling wheat fusarium rust and reducing the production of vomitoxin.

8. Use of the biocontrol agent according to any one of claims 2 to 3 in preventing and controlling wheat fusarium head blight and reducing the production of vomitoxin.

9. The use according to claim 8, characterized in that: The application method is: at the wheat heading stage or the early flowering stage, the biocontrol agent is evenly sprayed on the wheat ears.

10. Use of the strain according to claim 1, or the biocontrol agent according to any one of claims 2 to 3 in preventing and controlling rice blast, soybean blight, citrus black spot or bayberry wilt.

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