Bacillus for preventing and treating fruit tree diseases and application thereof

Abstract

The invention relates to bacillus for preventing and treating fruit tree diseases and application thereof. The bacillus velezensis GP34 provided by the invention has the preservation number of CGMCC (China General Microbiological Culture Collection Center) No.32908 in the General Microbiological Culture Collection Center of the China Committee for Culture Collection of Microorganisms, and the preservation number of the bacillus velezensis GP34 is CGMCC No.32908. The viable bacteria and metabolites of the strain have efficient prevention and treatment effects on apple early-stage leaf cast and grape white rot. The strain is short in fermentation culture time and low in production cost, the control effect is further improved when the strain is matched with a chemical agent, and the strain has a good application prospect.

Description

Technical Field

[0001] The invention belongs to the field of agricultural, forestry and horticultural crop plant protection, and particularly relates to a bacillus having a strong inhibitory effect on fruit tree diseases and its metabolites. Technical Background

[0002] Early leaf fall of apples refers to the early leaf fall of apple trees after they are damaged, which seriously weakens the tree vigor and even causes the overwintering buds to germinate, resulting in secondary flowering, which has a great impact on the yield of the following year; seedlings can also be affected, resulting in delayed planting or reduced grades. The leaf fall rate in severe orchards reaches 80%, which has a great impact on the quality and yield of the fruit that year and the flowering and fruiting of the next year. Early leaf fall of apples is mainly caused by infection with brown spot pathogens, leaf spot pathogens and anthracnose pathogens. It is an important disease in the apple producing areas of the northwest plateau and Shandong in my country in recent years. Grape white rot is one of the four major diseases in grape production, causing a loss of more than 10% to 50% in grape yield in general years. Grape white rot mainly harms the bunches, followed by new shoots and leaves. The disease is caused by white rot pad shell spores (Coniella diplodiella). The pathogen falls into the soil with the diseased residues and overwinters, becoming the source of initial infection in the second year. The pathogen invades the fruit before bagging, often causing a large number of fruit to fall and rot, causing heavy losses.

[0003] At present, chemical agents are mostly used for the prevention and control of apple leaf fall disease and grape white rot in production. Traditional chemical fungicides are widely promoted in China due to their convenience and low price, and are easily accepted by users. However, most fungicides face problems such as increased drug resistance, increased pesticide residues, and even agricultural non-point source pollution. There is a broad consensus in the whole society to reduce the use of chemical agents, but the premise of reducing the use of fungicides is that the prevention and control effect does not decrease. Therefore, finding economical and effective methods to reduce the amount of chemical fungicides and increase their effectiveness has become a major strategic need for China's current plant disease prevention and control. Fungi, actinomycetes and bacteria are biocontrol bacteria that have antagonistic effects on grape white rot. Among them, the antagonistic bacteria are mainly Bacillus subtilis, methylotrophic Bacillus, Bacillus amyloliquefaciens and Bacillus velezii. Chen Gongyou et al. (2019) reported that Bacillus B s26-7When the fermentation liquid was sprayed on fruit trees, the diseased leaf rate decreased by 39.62-46.91%, but the strain was not identified to species; Chen Liang et al. (2011) screened out Bacillus subtilis BS24, which has a plate inhibitory effect on a variety of apple leaf fall pathogens; Patent CN201910184437 reported that Bacillus Velezii BV2007 has an effective preventive effect on diseases caused by pathogens such as apple rot pathogens, ring rot pathogens, Fusarium oxysporum and Fusarium solani, but did not report its preventive effect on apple leaf fall disease. Gong Jie et al. (2010) selected strains of Bacillus subtilis PT2, and the composite agent of fermentation broth of this strain and fulvic acid can reduce the incidence of white rot of red grapes by 67%; Duan Haiming et al. (2018) studied the plate inhibitory activity of the secondary metabolite of Bacillus amyloliquefaciens gfj-4 and difenoconazole mixed agent against grape white rot fungi; Patent CN116622536A reported the indoor bio-test control effect of Bacillus velez GSBZ09 on grape white rot, which can reach up to 89.97%. Due to the different antagonistic spectra of different biocontrol bacteria, the control effects on different diseases are also different. At present, there is a severe lack of biocontrol bacteria for the prevention and control of various fruit tree diseases. We screened antagonistic bacteria against apple leaf fall disease caused by Colletotrichum gloeosporioides and grape white rot disease caused by Aspergillus niger, and obtained Bacillus GP34, which has a highly effective control effect on both diseases. Through 16S rRNA gene sequencing and whole genome sequencing, it was identified as Bacillus velezensis, which has great application potential. Summary of the invention

[0004] The invention aims to provide a bacillus strain having a preventive and therapeutic effect on apple leaf fall disease and grape white rot and application thereof.

[0005] The Bacillus provided by the present invention is specifically composed of Bacillus velezensis GP34, which has been deposited in the General Microbiology Center of China National Microbiological Culture Collection Committee (CGMCC for short, address: No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing) on ​​December 5, 2024, with a deposit number of CGMCC No. 32908.

[0006] The present invention also protects a bacterial agent whose active ingredient is the Bacillus velezensis GP34.

[0007] The bacterial agent may further include an adsorption carrier; the adsorption carrier may be at least one of diatomaceous earth, calcium carbonate, dextrin, and white carbon black.

[0008] More specifically, in one embodiment of the present invention, the adsorption carrier is specifically made of diatomaceous earth mixed in a certain volume-to-weight ratio. Further, the bacterial agent is made of the bacterial sludge obtained after centrifugation of the fermentation liquid of the Bacillus velezensis GP34 and the adsorption carrier in a weight ratio of 3:1 to 3:7 (such as 3g:1g). In Examples 3 to 5 of the present invention, a large amount of fermentation culture liquid is used to prepare the fermentation liquid of the Bacillus velezensis GP34, and the number of live bacteria of the Bacillus velezensis GP34 in the fermentation liquid of the Bacillus velezensis GP34 is 3 to 5 billion / mL of the fermentation liquid. The solvent of the large-scale fermentation culture solution is water, and the solute and concentration are as follows: corn flour 1.0-1.5%, soybean meal powder 1.0-2.0%, glucose 0.5-1.0%, yeast extract powder 0.05-0.2%, disodium hydrogen phosphate 0.1-0.2%, potassium dihydrogen phosphate 0.04-0.06%, calcium carbonate 0.1-0.2%, potassium chloride 0.01-0.015%, magnesium sulfate 0.01-0.015%, ammonium nitrate 0.03-0.045%, manganese sulfate 0.004-0.006%, pH 7.0; wherein % represents the mass percentage. Correspondingly, in the prepared bacterial agent, the number of live bacteria of Bacillus velezensis GP34 is 3-5 billion / g of the bacterial agent; the water content of the bacterial agent is within 5-8%.

[0009] The preparation method of the bacterial agent also belongs to the protection scope of the present invention.

[0010] The preparation method of the bacterial agent may specifically include the following steps:

[0011] (1) Cultivating the Bacillus velezensis GP34 to obtain a fermentation broth of the Bacillus velezensis GP34; in the fermentation broth, the number of live bacteria of the Bacillus velezensis GP34 is 3 to 5 billion / mL.

[0012] (2) Mixing the bacterial sludge obtained by centrifuging the fermentation liquid obtained in step (1) with the adsorption carrier in a weight ratio of 3:1 to 3:7 to obtain the bacterial agent.

[0013] In step (1), the solvent of the culture medium for culturing the Bacillus velezensis GP34 is water, and the solutes and concentrations are as follows: 1.0-1.5% corn flour, 1.0-2.0% soybean meal, 0.5-1.0% glucose, 0.05-0.2% yeast extract, 0.1-0.2% disodium hydrogen phosphate, 0.04-0.06% potassium dihydrogen phosphate, 0.1-0.2% calcium carbonate, 0.01-0.015% potassium chloride, 0.01-0.015% magnesium sulfate, 0.03-0.045% ammonium nitrate, 0.004-0.006% manganese sulfate, pH 7.0; wherein % represents the mass percentage.

[0014] More specifically, the solvent of the culture medium is water, and the solutes and concentrations are as follows: 1.0-1.5% corn flour, 1.0-2.0% soybean meal, 0.5-1.0% glucose, 0.05-0.2% yeast extract, 0.1-0.2% disodium hydrogen phosphate, 0.04-0.06% potassium dihydrogen phosphate, 0.1-0.2% calcium carbonate, 0.01-0.015% potassium chloride, 0.01-0.015% magnesium sulfate, 0.03-0.045% ammonium nitrate, 0.004-0.006% manganese sulfate, pH 7.0; wherein % represents the mass percentage.

[0015] The fermentation broth of Bacillus velezensis GP34 also belongs to the protection scope of the present invention.

[0016] The invention also provides a product for preventing and controlling apple leaf fall disease and grape white rot disease.

[0017] The use of the Bacillus velezensis GP34 or the bacterial agent or the fermentation broth in the following (1) or (2) also falls within the protection scope of the present invention:

[0018] (1) Prevent and control early leaf fall of apples caused by Colletotrichum gloeosporioides and white rot of grapes caused by Aspergillus niger.

[0019] (2) Prepare products for preventing and controlling diseases described in (1).

[0020] The Bacillus velezensis GP34 CGMCC No.32908 provided by the present invention has the following advantages:

[0021] 1. This strain was obtained by screening using high-salt culture medium and has very good adaptability to salt stress.

[0022] 2. This strain has a high efficacy in preventing and controlling apple leaf fall and grape white rot, has a short fermentation cycle, low cost, and is easy for large-scale production and commercial application.

[0023] The Bacillus velezensis GP34 CGMCC No.32908 provided by the present invention is a strain of Bacillus isolated from grape rhizosphere soil by the inventor in September 2023, which has a highly effective antagonistic effect on grape white rot and apple early leaf fall. The characteristics of the strain are: the colonies of strain GP34 on NA medium (beef extract 3.0g, peptone 7.0g, sodium chloride 5.0g, agar 20g, distilled water 1L, pH 7.0-7.2) are white, but opaque, with a rough and wrinkled surface and a dry texture. The strain can achieve a preventive effect of 60.7% on apple leaf fall caused by Colletotrichum gloeosporioides, and a preventive effect of 66.7% on grape white rot. When used in combination with the chemical pesticide methylpyralidone, the preventive effect on grape white rot can reach more than 90.0%. During fermentation, the strain GP34 grows fast and can complete fermentation within 72 hours. After fermentation, the number of live bacteria can reach 3-5 billion / mL, which greatly reduces the cost of use. Therefore, GP34 is a very potential bacterium, and the present invention is proposed.

[0024] Collection Instructions

[0025] Bacteria name: Bacillus velez

[0026] Latin name: Bacillus velezensis

[0027] Strain ID: GP34

[0028] Depository: China National Microbiological Culture Collection Administration General Microbiology Center

[0029] Abbreviation of depository institution: CGMCC

[0030] Address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing

[0031] Deposit date: December 5, 2024

[0032] CGMCC Registration Number: CGMCC No.32908 DETAILED DESCRIPTION

[0033] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0034] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0035] Example 1: Antagonistic screening of antagonistic bacteria GP34

[0036] The activated strains were transferred from 38 salt-tolerant bacteria preserved in the laboratory, and the inhibitory activity of the bacteria against three gloeosporium anthracnose and one white rot fungus was determined by the plate confrontation culture method. First, the bacteria were streaked 1 cm away from the edge of the plate, and 4 strains were inoculated on each plate. After culturing at 28℃ for 2 to 3 days, a fungal cake with a diameter of 5 mm was inoculated in the center of the culture medium, and only a 5 mm fungal cake was inoculated in the control group. The culture was continued at 28℃ for 4 to 5 days, and the width of the inhibition zone (mm) was measured with a vernier caliper.

[0037] The results of antagonistic assays showed that there were 24 antagonistic bacteria with an inhibition rate of more than 55% against one of the above four pathogens, among which strains GP34 and GS35 had better antagonistic effects against the above pathogens (Table 1).

[0038] Table 1 Inhibition rate of bacteria against apple early leaf fall and grape white rot pathogens (%)

[0039]

[0040] Note: PG1, PG2, PG3 are apple anthracnose, PT1 is grape white rot

[0041] Example 2: Effect of fermentation liquid of two antagonistic bacteria on the prevention of early leaf fall disease in apple

[0042] (1) Preparation of pathogen spore suspension: Inoculate the apple anthracnose strain onto a PDA plate and culture at 25°C for 5 days. Take one plate, rinse it with 5 mL of sterile water, and then filter it into a triangular flask with three layers of sterile lens paper to obtain a spore suspension. Dilute it with sterile water, count it with a hemocytometer, and then adjust the concentration of the spore suspension to 1×10 5 Pieces / mL.

[0043] The solvent of the PDA culture medium is water, and the solute and concentration are as follows: 200g peeled potato, 20g glucose, 20g agar, 1000mL distilled water. Production process: Cut the peeled potato into small pieces, put it into a pot, add 1000mL distilled water, boil for 20-30 minutes, then filter with gauze, retain the filtrate, add 20g glucose, add 20g agar after melting, heat and dissolve, and add water to 1000mL. Sterilize at 121℃ for 25 minutes and set aside.

[0044] (2) Preparation of antagonistic bacterial fermentation broth: strains GP34 and GS35 were inoculated into beef extract peptone culture medium NB, respectively, and cultured at 30°C and 180 r / min for 20 h. 10% of the inoculum was transferred to the fermentation medium, with a liquid volume of 100 mL / 500 mL, and cultured at 30°C and 180 r / min for 48 to 72 h.

[0045] The solvent of the NB culture solution is water, and the solutes and concentrations are as follows: 3.0 g beef extract, 7.0 g peptone, 5.0 g sodium chloride, 1 L distilled water, pH 7.0-7.2.

[0046] The solvent of the fermentation liquid medium is water, and the solutes and concentrations are as follows: 1.0% corn flour, 1.0% soybean meal, 0.5% glucose, 0.05% yeast extract powder, 0.1% disodium hydrogen phosphate, 0.04% potassium dihydrogen phosphate, 0.1% calcium carbonate, 0.01% potassium chloride, 0.01% magnesium sulfate, 0.03% ammonium nitrate, 0.004% manganese sulfate, 1000mL distilled water, pH 7.0; wherein % represents the mass percentage.

[0047] After 48 hours of culture, the antagonistic bacteria GP34 and GS35 began to produce spores. At 72 hours, the spore production rate reached more than 90%, and the number of bacteria could reach 3 billion / mL.

[0048] (3) Effect of antagonistic bacteria fermentation liquid on the control of leaf fall disease of isolated apple branches: 9 healthy apple branches with uniform growth were selected, and about 10 disease-free young leaves were retained on each branch. The 9 branches were divided into three groups, one of which was a water control group, and the other two groups were treated with 1×10 8 Treat with GP34 fermentation liquid and GS35 fermentation liquid of 105 / mL. After the fermentation liquid spray treatment, insert the branches into a mineral water bottle with a small amount of water (the water covers the branches by 1-2cm) and place them in a 25℃ light incubator. After 48 hours, spray and inoculate the apple anthracnose fungus PG1 spore suspension at a concentration of 1×105 / mL, cover the branches with air-filled plastic bags to keep them moist, and continue to culture in a 25℃ light incubator. 3-4 days after inoculation, count the number and area of ​​lesions on the leaves.

[0049] The statistical results of the number and area of ​​lesions (Table 2) showed that the GP34 fermentation liquid treatment had a good disease prevention effect on apple leaf fall disease, reaching 58.14%.

[0050] Table 2 The control effect of fermentation liquid of antagonistic bacteria GP34 and GS35 on early leaf fall disease of apple

[0051]

[0052] Example 3: Effect of fermentation liquid of two antagonistic bacteria on early leaf fall disease of different apple varieties

[0053] (1) Preparation of pathogenic bacteria spore suspension: The method is the same as Example 2(1).

[0054] (2) Preparation of antagonistic bacteria GP34 fermentation broth: The basic method is the same as Example 2 (2), the liquid volume is changed to 75mL / 500mL, and the fermentation medium formula is slightly different. The solvent of the fermentation medium is water, and the solutes and concentrations are as follows: 1.2% corn flour, 1.5% soybean meal, 1.0% glucose, 1.0% yeast extract powder, 0.2% disodium hydrogen phosphate, 0.06% potassium dihydrogen phosphate, 0.2% calcium carbonate, 0.015% potassium chloride, 0.015% magnesium sulfate, 0.045% ammonium nitrate, 0.006% manganese sulfate, 1000mL distilled water, pH 7.0; wherein % represents the mass percentage.

[0055] After 42 hours of culture, the antagonistic bacteria GP34 and GS35 began to produce spores. At 72 hours, the spore production rate reached more than 92%, and the number of bacteria could reach 4 billion / mL.

[0056] (3) Determination of protective efficacy: Healthy Gala and Shinano Gold young and old branches with consistent growth were selected for the experiment, and about 10 disease-free young leaves were retained on each branch. The Gala branches were divided into four groups. The first and second groups were treated with antagonistic bacteria GP34 and GS35, respectively, the third group was treated with 40% difenoconazole + antagonistic bacteria GP34, and the fourth group was treated with water. The Shinano Gold young branches were divided into three groups. The first group was treated with 40% difenoconazole, the second group was treated with 40% difenoconazole + antagonistic bacteria GP34, and the third group was treated with water. The Shinano Gold old branches were divided into two groups. The first group was treated with antagonistic bacteria GP34, and the second group was treated with water. Three branches were treated for each treatment. After spraying, the branches were inserted into a mineral water bottle containing a small amount of water (the water covered the branches by 1-2 cm) and placed in a 25°C light incubator. After 48 hours, spray inoculate with a spore suspension of apple anthracnose at a concentration of 1×10 5 / mL, cover the branches with air-filled plastic bags to keep them moist, and continue to place them in a 25℃ light incubator. 3-4 days after inoculation, count the number of leaf spots; 7-11 days after inoculation (the diseased area of ​​the leaves in the control group is nearly 100%), calculate the disease index according to the grading standard.

[0057] The severity grading standard for apple anthracnose leaf blight is: Level 0, no obvious symptoms; Level 1, the lesion area is less than 10%; Level 2, the lesion area is 10% to 30%; Level 3, the lesion area is 30% to 50%; Level 4, the lesion area is 50% to 80%; Level 5, the lesion area is greater than 80%.

[0058] The experimental results show that whether it is Gala or Shinano Gold, the young leaves of the same variety are more susceptible to disease than the old leaves. Comparing the disease index of the blank control of the two varieties, it was found that Shinano Gold was more susceptible to disease than Gala. In the two antagonistic bacteria treatments, the GP34 fermentation liquid had a protective effect of 60.71% on Gala apple young leaves and 74.36% on old leaves, which was higher than the chemical pesticide 40% difenoconazole + GP34 treatment (Table 3, Table 4).

[0059] Table 3 The control effect of different antagonistic bacteria fermentation liquid on Gala apple early leaf fall disease

[0060]

[0061] Table 4 The control effect of different antagonistic bacteria fermentation liquid on early leaf fall disease of Shinano Golden Apple

[0062]

[0063] Example 4: Effect of the fermentation liquid of antagonistic bacteria GP34 on the control of white rot of Monlisa grape

[0064] (1) Preparation of antagonistic bacteria GP34 fermentation broth: The method is basically the same as Example 2 (2). The liquid volume is 50mL / 500mL. The solvent of the fermentation broth medium is water, and the solutes and concentrations are as follows: 1.5% corn flour, 2.0% soybean meal, 0.5% glucose, 1.0% yeast extract powder, 0.2% disodium hydrogen phosphate, 0.06% potassium dihydrogen phosphate, 0.2% calcium carbonate, 0.015% potassium chloride, 0.015% magnesium sulfate, 0.045% ammonium nitrate, 0.006% manganese sulfate, 1000mL distilled water, pH 7.0; wherein % represents the mass percentage.

[0065] After 40 hours of culture, the antagonistic bacteria GP34 began to produce spores. At 72 hours, the spore production rate reached more than 95%, and the number of bacteria could reach 5 billion / mL.

[0066] (2) Preparation of grape white rot fungus spore suspension: Inoculate the white rot fungus on PDA medium and culture it in a 28°C incubator for 7-10 days. When the surface of the medium is covered with black conidia, add 1 mL of sterile water and use a sterile applicator to scrape the surface spores to make a spore suspension. Filter it with sterile lens paper to remove the hyphae. Use a hemocytometer to adjust the concentration of the spore suspension to 10 5 Pieces / mL.

[0067] (3) In vitro fruit test: Select healthy, bright-colored, and wound-free grape berries with stems, soak them in 75% alcohol for 2 min, rinse them with sterile water 3 times, and place them in a clean bench to dry the surface moisture. Use a 2 mm long wedge-shaped white gun tip to pierce the center of the grape berry. Soak the grape wound in sterile water or 1×10 8 / mL GP34 fermentation liquid for 30 minutes, and then transferred to a new sterile culture dish. After 24 hours, place a 5mm sterile filter paper on the surface of the fruit wound, and then drop 2μL of 1×10 8The inoculated grapes were placed in a sealable plastic fresh-keeping box covered with sterile wet gauze. Five grapes were placed in each plastic box, and five replicates were performed for each treatment. The uninoculated spore suspension of the pathogen was used as a blank control. All treated grapes were placed in an artificial climate incubator at 28°C and a photoperiod of 12h for 7 days, and the disease was observed, the size of the lesions was counted, and the disease index and relative control effect were calculated.

[0068] The results of bioassay showed that soaking grape wounds in GP34 suspension could reduce the occurrence of white rot, and the incidence rate was reduced by 66.7% (Table 5).

[0069] Table 5 The effect of bacterial GP34 solution on the prevention of white rot of Monlisa grape

[0070]

[0071] Example 5: Control effect of antagonistic bacteria GP34 fermentation liquid on white rot of rose-scented grape

[0072] (1) Preparation of fermentation broth of antagonistic bacteria GP34: The method is the same as Example 4(1).

[0073] (2) Preparation of grape white rot fungus spore suspension: The method is the same as Example 4 (2).

[0074] (3) In vitro fruit test: Grape fruit was prepared in the same manner as in Example 4(3). The test treatments were 1. clean water control; 2. 10% difenoconazole (40% difenoconazole diluted 4 times); 3. fermentation broth of antagonistic bacteria GP34; 4. 10% difenoconazole + GP34 fermentation broth; 5. GP34 fermentation broth + 10% difenoconazole. Each treatment was repeated ten times. Treatment 4 was first sprayed with 10% difenoconazole, and then 10 hours later, the fermentation broth of antagonistic bacteria GP34 was sprayed. Treatment 5 was first sprayed with GP34 fermentation broth, and then 10 hours later, 10% difenoconazole was sprayed. 24 hours after inoculation, 10 μL of the spore suspension was aspirated with a pipette and inoculated into the wound of the fruit. The culture method and culture conditions and the disease investigation method were the same as in Example 4(3).

[0075] The results showed that the control effect of 10% difenoconazole was not high, with a control effect of only 20%; the control effect of the fermentation broth of the antagonistic bacteria GP34 reached 80%; when 10% difenoconazole and fermentation broth GP34 were used in combination, the control effect could reach more than 90% (Table 6).

[0076] Table 6 The efficacy of the fermentation liquid of antagonistic bacteria GP34 against white rot of rose-scented grape

[0077]

[0078] Example 6: Identification of Antagonistic Bacteria GP34 Strain

[0079] The bacterial morphology of the antagonistic bacterium GP34 was observed microscopically, and Gram staining and H2O2 enzyme activity were determined. The results showed that the strain

[0080] GP34 was Gram-positive and H2O2 enzyme activity was positive. The colonies of strain GP34 on NA medium (glucose 10g / L, peptone 10g / L, yeast extract 3g / L, beef extract 3g / L, agar 20g, distilled water 1000mL, pH 7.0) were white, round, with irregular edges, rough and wrinkled surface, and dry texture. The strain can produce spores and the bacteria are rod-shaped. The genomic DNA of strain GP34 was extracted, and the 16S rRNA gene sequence was amplified with universal primers 27F and 1492R, and sequenced. 27F: 5'-AGA GTTTGA TCC TGG CTC AG-3'; 1492R: 5′-TAC GGC TAC CTF GTT ACG ACTT-3′. The 16S rRNA gene sequence of strain GP34 has been submitted to GenBank with the accession number PV012485; its whole genome sequence has also been submitted to GenBank with the submission number SUB15028051 (BioProject: PRJNA1214702). Based on the 16S rRNA gene sequence and whole genome sequence of strain GP34, it was identified as Bacillus velezensis. Strain GP34 was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration (CGMCC, address: No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing) on ​​December 5, 2024, and the deposit number of strain GP34 is CGMCC No.32908.

Claims

1. Bacillus velezensis GP34, deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with the deposit number CGMCC No.32908.

2. A bacterial agent, characterized in that The active ingredient of the bacterial agent is the Bacillus velezensis GP34 described in claim 1.

3. The bacterial agent according to claim 2, characterized in that: The bacterial agent is a liquid bacterial agent, and the number of live bacteria of Bacillus velezensis GP34 in the liquid bacterial agent is 3 to 5 billion / mL.

4. The bacterial agent according to claim 2, characterized in that: The bacterial agent is a solid bacterial agent, which is a mixture of bacterial sludge obtained after centrifugation of the fermentation liquid of Bacillus velezensis GP34 and an adsorption carrier in a weight ratio of 3:1 to 3:

7.

5. The bacterial agent according to claim 4, characterized in that The preparation method of the solid bacterial agent comprises the following steps: Cultivating Bacillus velezensis GP34 to obtain a fermentation liquid of Bacillus velezensis GP34; The bacterial sludge after centrifugation of the fermentation liquid is mixed with the adsorption carrier in a weight ratio of 3:1 to 3:7 to obtain the bacterial agent; The culture medium solvent of the Bacillus velezensis GP34 is water, and the culture medium solutes and concentrations are as follows: 1.0-1.5% corn flour, 1.0-2.0% soybean meal powder, 0.5-1.0% glucose, 0.05-0.2% yeast extract powder, 0.1-0.2% disodium hydrogen phosphate, 0.04-0.06% potassium dihydrogen phosphate, 0.1-0.2% calcium carbonate, 0.01-0.015% potassium chloride, 0.01-0.015% magnesium sulfate, 0.03-0.045% ammonium nitrate, 0.004-0.006% manganese sulfate, pH 7.0; wherein % represents the mass percentage content.

6. The Bacillus velezensis GP34 according to claim 1, the bacterial agent according to any one of claims 2 to 4, and their use in the prevention and treatment of apple early leaf fall disease and grape white rot.

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