Paenibacillus taohuashanensis and application thereof

Abstract

The present application belongs to the field of agricultural microorganism technology, and particularly relates to a Paenibacillus taohuashanense and application thereof. The Paenibacillus taohuashanense is named Paenibacillus taohuashanense GD1, and was preserved in Guangdong Microbial Culture Collection Center on January 19, 2024, with an address of 59# Building, 5th Floor, 100 Institute, Junli Middle Road, Guangzhou, China, and a preservation number of GDMCC No 64296. The strain has a fast growth speed, has the ability of producing protease, and has a broad-spectrum bacteriostatic effect, has good bacteriostatic property on various plant pathogenic fungi, can be used as a biocontrol agent to prevent and treat various plant diseases, and enriches the strain resources of protease-producing bacteria and biocontrol agents.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of agricultural microorganism technology, and particularly relates to a peach blossom mountain bacillus and application thereof. BACKGROUND

[0002] Citrus is one of the main economic crops in China, and China is one of the world's major citrus producing countries. In the southern region of China, citrus is the most widely planted fruit tree with the most important economic status. Citrus penicillium disease, citrus soot disease, citrus anthracnose disease and citrus gray mold disease are common diseases of citrus.

[0003] Citrus penicillium disease is caused by Penicillium italicum. In the early stage of the disease, the fruit peel softens, water stains, and is easily broken with light pressure. After that, many aerial hyphae grow on the surface of the lesion, forming a thick white mold layer, which expands rapidly into a white nearly round mold spot. Then green or greenish powder grows from the middle of the mold spot. The pathogen of penicillium disease is widespread around the world, and generally saprophytic on various organic matter, producing a large number of conidia which are transmitted by air flow, and invading citrus fruits through wounds. During storage and transportation, it can also be infected through contact between healthy and diseased fruits. The rotting of fruits produces a large amount of carbon dioxide, which is absorbed by water vapor in the air to produce dilute carbonic acid to corrode the fruit peel and make the fruit surface pH acidic, promoting the invasion of the pathogen and leading to a large number of rotten fruits.

[0004] Citrus soot disease is a common disease that occurs on citrus, which is generally caused by a variety of saprophytic and parasitic fungi, and the common anamorphic state includes Cladosporium etc. Citrus soot disease mainly damages leaves, branches and fruits; in the early stage of the disease, a layer of dark brown small mold spots appears on the diseased part, which gradually expands until a black or dark brown mold layer with scattered black spots is formed; when it occurs seriously, a thick layer of soot covers the surface of citrus leaves, branches and fruits, hindering photosynthesis, weakening tree vigor, accelerating water transpiration of the tree, causing leaf curling and shedding, less flowering and fruiting, and even causing dead trees and destroyed orchards.

[0005] Citrus anthracnose disease, commonly known as peel disease, mainly damages leaves, branches, flowers, fruits, fruit stalks and seedlings, often causing leaf and shoot wilting, flower and fruit drop and fruit rot. Citrus anthracnose disease occurs in all parts of China, affecting yield and quality, and causing dead trees and destroyed orchards when it occurs seriously.

[0006] Citrus gray mold disease refers to the disease caused by the infection of citrus with Botrytis cinerea. The pathogen of the disease is Botrytis cinerea. It mainly damages petals, young leaves, young fruits and branches, causing flower rot, branch wilting and reduced fruit setting rate. The damaged petals will have water spots at the early stage, and will rot and produce a gray mold layer at the later stage; the damaged leaves and branches will gradually wither; the young fruit lesions, flower petals and fruits will swell, affecting the appearance of the fruits; when the mature fruits start to grow, they will turn brown and soft, covered with a gray mold layer, and will fall off after drying and losing water.

[0007] Protease is one of the three major enzyme preparations in the world, which is widely used in medicine, food, brewing, tanning, feed, paint and other industries, and plays a positive role in economy, society, environmental protection and other aspects. Protease widely exists in animals, plants and microorganisms. Among them, the microorganism protease is mainly produced by molds, bacteria, followed by yeasts and actinomycetes. Some protease-producing microorganisms can also be used for environmental purification, and play a biological repair function by degrading harmful chemicals and toxic substances.

[0008] There are few microbial strains disclosed in the prior art that can produce protease and inhibit plant pathogenic bacteria. Therefore, it is of great significance for the development of agricultural industry and environmental protection in China to isolate and screen microbial strains that can produce protease and inhibit plant pathogenic bacteria (especially can inhibit common citrus diseases). SUMMARY

[0009] In order to overcome the deficiencies and shortcomings of the prior art, the primary purpose of the present application is to provide a Taohuashan-like Bacillus, which has good protease production capacity and also has good bacteriostatic effect, and can be used for plant growth promotion and plant disease prevention and control.

[0010] Another purpose of the present application is to provide the application of the above-mentioned Taohuashan-like Bacillus.

[0011] Still another purpose of the present application is to provide a plant pathogenic bacteria inhibitor or a biocontrol agent, which comprises the above-mentioned Taohuashan-like Bacillus and / or its fermentation liquor.

[0012] The fourth purpose of the present application is to provide a method for preventing and treating plant diseases.

[0013] The purposes of the present application are achieved by the following technical solutions:

[0014] A Taohuashan-like Bacillus, named Paenibacillus taohuashanense GD1, was deposited in the Guangdong Microbial Culture Collection Center on January 19, 2024, and the address of the deposit is: No. 59 Building, 5th Floor, 100 Institute, Xianlie Middle Road, Guangzhou, China, and the deposit number is: GDMCC No. 64296;

[0015] The Taohuashan-like Bacillus GD1 is isolated from tobacco rhizosphere soil samples;

[0016] The Taohuashan-like Bacillus GD1 has the following morphological characteristics:

[0017] (1) Single colony is approximately circular, yellowish, milky, and the colony surface is smooth;

[0018] (2) Gram stain red, gram-negative bacteria;

[0019] The peach blossom mountain type bacillus and / or the fermentation liquor thereof in the field of protease preparation or plant growth promotion;

[0020] The peach blossom mountain type bacillus and / or the fermentation liquor thereof in the field of inhibiting plant pathogenic bacteria, preventing and treating plant diseases caused by plant pathogenic bacteria, or preparing plant pathogenic bacteria inhibitors or biocontrol agents;

[0021] The plant is preferably citrus;

[0022] The plant pathogenic bacteria are preferably at least one of Penicillium italicum, Cladosporium cladosporioides, Colletotrichum fructicola and Botrytis cinerea;

[0023] The plant diseases are preferably at least one of citrus penicillium disease, citrus soot disease, citrus anthracnose and citrus gray mold;

[0024] A plant pathogenic bacteria inhibitor or biocontrol agent comprising the above-mentioned peach blossom mountain type bacillus and / or fermentation liquor thereof;

[0025] A method for preventing and treating plant diseases, comprising the following steps:

[0026] Using the above-mentioned peach blossom mountain type bacillus and / or fermentation liquor thereof to treat plant plants;

[0027] The peach blossom mountain type bacillus fermentation liquor is preferably prepared by the following steps:

[0028] (1) After activation, the peach blossom mountain type bacillus is streaked on LB solid medium and cultured at 28°C until single colonies grow;

[0029] (2) The single colonies after step (1) are picked into LB liquid medium and shaken at 28°C, 150-240 rpm to obtain seed liquid;

[0030] (3) The seed liquid is added to LB liquid medium and shaken at 28°C, 150-240 rpm to obtain the peach blossom mountain type bacillus fermentation liquor;

[0031] The treatment mode is preferably spraying;

[0032] The plant is preferably citrus;

[0033] The present application has the following advantages and effects relative to the prior art:

[0034] (1) The present application separates a Paenibacillus taohuashanense strain, named Paenibacillus taohuashanense GD1, which has a fast growth rate and good protease production capacity and can be applied in the field of plant growth promotion.

[0035] (2) The Paenibacillus taohuashanense provided by the present application has a significant inhibitory effect on a variety of plant pathogenic fungi and has good broad-spectrum antibacterial properties, and has a significant inhibitory effect on Penicillium italicum, Cladosporium cladosporioides, Colletotrichum fructicola and Botrytis cinerea, with an inhibition rate of 88%, 72.77%, 52.25% and 74.5%, respectively, and can be used as a biocontrol agent to control a variety of plant diseases.

[0036] (3) The present application enriches the strain resources of protease-producing bacteria and biocontrol agents, and the strain has not been genetically modified and can be applied in industrial production and the development of biological pesticides. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a colony morphology diagram of the Paenibacillus taohuashanense GD1 strain.

[0038] Figure 2 is a gram staining result diagram of the Paenibacillus taohuashanense GD1 strain.

[0039] Figure 3 is a 16s rDNA gene phylogenetic tree result diagram of the Paenibacillus taohuashanense GD1 strain.

[0040] Figure 4 is a result display diagram of the Paenibacillus taohuashanense GD1 strain producing a transparent circle on the protease detection medium.

[0041] Figure 5 is an inhibition effect diagram of the Paenibacillus taohuashanense GD1 strain on Penicillium italicum.

[0042] Figure 6 Figure is the inhibition effect diagram of Paenibacillus taohuashanense GD1 strain on Cladosporium cladosporioides.

[0043] Figure 7 Figure is the inhibition effect diagram of Paenibacillus taohuashanense GD1 strain on Guignardia bidwelli.

[0044] Figure 8 Figure is the inhibition effect diagram of Paenibacillus taohuashanense GD1 strain on Botrytis cinerea.

[0045] Figure 9 Figure is the prevention effect display diagram of Paenibacillus taohuashanense GD1 strain on Penicillium citri. DETAILED DESCRIPTION

[0046] The application will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the application are not limited thereto.

[0047] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0048] The main culture medium composition and content involved in the examples are as follows:

[0049] King's solid medium: sodium nitrate 3 g / L, dipotassium hydrogen phosphate 1 g / L, magnesium sulfate 0.5 g / L, potassium chloride 0.5 g / L, ferrous sulfate 0.01 g / L, sucrose 30 g / L, agar 15-20 g / L, pH natural or 7.0-7.2, sterilized at 121℃ for 20 min.

[0050] LB liquid medium: yeast extract 5 g, tryptone 10 g, NaCl 10 g, distilled water 1000 mL, pH 7.2, sterilized at 121℃ for 20 min.

[0051] LB solid medium: yeast extract 5 g, tryptone 10 g, NaCl 10 g, distilled water 1000 mL, agar 17 g, pH 7.0, autoclaved at 121℃ for 20 min.

[0052] PDA plate: potato 200 g, glucose 20 g, distilled water 1 L; autoclaved at 121℃ for 20 min, and poured into a plate.

[0053] Protease detection medium: skimmed milk powder 10 g, agar 15 g, K2HPO4 1 g, MgSO4·7H2O 0.5 g, FeSO4·7H2O (100 g / L) 0.1 mL, NaCl 0.5 g, distilled water 1 L, pH 7.2-7.4; high pressure sterilization at 121°C for 20 min.

[0054] Isolation and identification of strains in Example 1

[0055] 1. Isolation of strains

[0056] (1) The soil sample was derived from tobacco rhizosphere soil in Shaoguan City, Guangdong Province. After collecting the tobacco rhizosphere soil sample, 1 g of tobacco rhizosphere soil was weighed into a sterile triangular flask, 100 mL of sterile water was added, and the soil suspension was obtained by shaking at 28°C and 180 rpm for 30 min.

[0057] (2) After centrifuging the soil suspension at 5000 r / min for 10 min, the supernatant was spread on Czapek solid medium and cultured at 28°C for 1 day to grow colonies.

[0058] (3) Single colonies were picked and streaked on new Czapek solid medium. After the colonies grew, single colonies were picked and cultured in LB liquid medium at 28°C and 180 rpm for 24 h. The bacterial solution was mixed with glycerol and stored at -80°C according to the conventional method. The purified bacteria were named as GD1 strain.

[0059] 2. Morphological characteristics identification

[0060] The GD1 strain isolated in step 1 was cultured on LB solid medium, and the colony color, morphological characteristics were observed and recorded, and the cell morphology was observed by microscope and Gram staining.

[0061] The colony morphology of GD1 strain is shown in Figure 1 From Figure 1 it can be seen that the single colony of the bacteria is approximately circular, slightly yellow, milky, and the colony surface is smooth.

[0062] The Gram staining result of GD1 strain is shown in Figure 2 From Figure 2 it can be seen that the Gram staining is red, indicating that GD1 strain is a Gram-negative bacterium.

[0063] 3. Physiological and biochemical identification

[0064] Referring to the "Common Bacteria System Identification Manual", the GD1 strain was used as the object to perform peroxidase test, oxidase test, nitrate reduction test, V-P test, etc. The results are shown in Table 1.

[0065] Table 1 Physiological and biochemical results of GD1 strain

[0066]

[0067] Note: "+" is a positive result, "-" is a negative result, "(+)" is a weak positive result

[0068] 4. Sequence homology analysis and phylogenetic tree construction

[0069] (1) The genomic DNA of GD1 strain was extracted by boiling water bath method with bacterial suspension.

[0070] (2) The genomic DNA prepared in step (1) was used as a template, and bacterial 16S rDNA universal primers 27F (5'-AGAGTTTGATCCTGGCTCAG-3') and 1492R (5'-GGTTACCTTGTTACGACTT-3') were used as amplification primers for PCR amplification, wherein the PCR reaction system was: DNA template 1 μL, upstream and downstream primers 0.5 μL each, Taq polymerase mixture 10 μL, and ddH2O was supplemented to 20 μL; the PCR amplification program was: 95°C pre-denaturation for 5 min; 95°C denaturation for 30 s, 54°C annealing for 30 s, 72°C extension for 1 min 30 s, a total of 32 cycles; finally 72°C extension for 10 min.

[0071] (3) The PCR amplification product of 16S rDNA obtained in step (2) was detected by 1% agarose gel electrophoresis, and the PCR amplification product of 16S rDNA was sent to Shanghai Sangon Biological Technology Co., Ltd. for sequencing.

[0072] (4) The sequencing results were submitted to NCBI database for BLAST homology analysis, and MEGA 11.0 software was used for sequence alignment and construction of phylogenetic tree.

[0073] The 16S rDNA sequence fragment size of GD1 strain was 1455 bp, and the specific sequence was as shown below; based on the 16S rDNA sequence of GD1 strain, BLAST alignment analysis was performed in NCBI database, and the results showed that the homology of GD1 strain and Paenibacillus taohuashanense reached 98%. MEGA5.0 software was used to further construct a phylogenetic tree, and the results are shown in Figure 3 From Figure 3 it can be seen that: GD1 strain and Paenibacillus taohuashanense are in the same branch, and the genetic relationship is the closest.

[0074] The 16S rDNA sequence of GD1 strain is:

[0075] GCCCCCTACGTGCCTAATACATGCAAGTCGAGCGGAGTTATGAAGGAGCTTGCTCCGGATTAACTTAG

[0076] CGGCGGACGGGTGAGTAACACGTAGGCAACCTACCTCTTTGACTGGGATAACTACCGGAAACGGTAG

[0077] CTAATACCGGATAATTCCTTTGTTCACATGGACGAAGGATGAAAGGCGGAGCAATCTGCTACAAGGAG

[0078] ATGGGCCTGCGGCGCATTAGCTAGTTGGTGGGGTAACGGCTCACCAAGGCGACGATGCGTAGCCGAC

[0079] CTGAGAGGGTGAACGGCCACACTGGGACTGAGACACGGCCCAGACTCCTACGGGAGGCAGCAGTAG

[0080] GGAATCTTCCGCAATGGGCGAAAGCCTGACGGAGCAACGCCGCGTGAGTGATGAAGGTTTTCGGATC

[0081] GTAAAGCTCTGTTGCCAGGGAAGAACGTCCGGTAGAGTAACTGCTACCGGAGTGACGGTACCTGAGA

[0082] AGAAAGCCCCGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGGGGCAAGCGTTGTCCGGAAT

[0083] TATTGGGCGTAAAGCGCGCGCAGGCGGCTATTTAAGTCTGGTGTTTAAACCTTGGGCTCAACCTGAGG

[0084] TCGCACTGGAAACTGGGTGGCTTGAGTACAGAAGAGGAAAGTGGAATTCCACGTGTAGCGGTGAAAT

[0085] GCGTAGATATGTGGAGGAACACCAGTGGCGAAGGCGACTTTCTGGGCTGTAACTGACGCTGAGGCGC

[0086] GAAAGCGTGGGGAGCAAACAGGATTAGATACCCTGGTAGTCCACGCCGTAAACGATGAGTGCTAGGT

[0087] GTTAGGGGTTTCGATACCCTTGGTGCCGAAGTTAACACAGTAAGCACTCCGCCTGGGGAGTACGGTC

[0088] GCAAGACTGAAACTCAAAGGAATTGACGGGGACCCGCACAAGCAGTGGAGTATGTGGTTTAATTCGA

[0089] AGCAACGCGAAGAACCTTACCAGGTCTTGACATCCCTCTGAATCCACTAGAGATAGTGGCGGCCTTCG

[0090] GGACAGAGGAGACAGGTGGTGCATGGTTGTCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCG

[0091] CAACGAGCGCAACCCTTGACTTTAGTTGCCAGCAGGTTAAGCTGGGCACTCTAGAGTGACTGCCGGT

[0092] GACAAACCGGAGGAAGGTGGGGATGACGTCAAATCATCATGCCCCTTATGACCTGGGCTACACACGT

[0093] ACTACAATGGCCGGTACAACGGGAAGCGAAGCCGCGAGGTGGAGCCAATCCCAGCAAAGCCGGTCT

[0094] CAGTTCGGATTGCAGGCTGCAACTCGCCTGCATGAAGTCGGAATTGCTAGTAATCGCGGATCAGCATG

[0095] CCGCGGTGAATACGTTCCCGGGTCTTGTACACACCGCCCGTCACACCACGAGAGTTTACAACACCCG

[0096] AAGTCGGTGGGGTAACCCGCAAGGGAGCCAGCCGCCGAAGGTTGG

[0097] Based on the morphological, physiological and biochemical, and biomolecular identification results of strain GD1, strain GD1 was classified as Paenibacillus taohuashanense and named Paenibacillus taohuashanense GD1. It was deposited on January 19, 2024, at the Guangdong Provincial Center for Microbial Culture Collection, located at 5th Floor, Building 59, No. 100 Courtyard, Xianlie Middle Road, Guangzhou, China, with accession number GDMCC No. 64296.

[0098] Example 2: Protease production capacity of Paenibacillus taohuashanense GD1 strain

[0099] 1. Preparation of fermentation broth for GD1 strain

[0100] (1) Activate the GD1 strain stored at -80℃, pick out the activated single colony and streak it on LB solid medium, and incubate at 28℃ for 48h.

[0101] (2) Pick a single colony after culturing in step (1) and put it into LB liquid medium. Shake and incubate at 28℃ and 180rpm for 24h to obtain the seed liquid of strain GD1.

[0102] (3) At an inoculation ratio of 1:100 between the seed culture and LB liquid medium, the seed culture of strain GD1 was added to LB liquid medium and incubated at 28°C and 180 rpm for 12 hours to obtain the fermentation broth of strain GD1. The concentration of this fermentation broth was determined to be approximately 7 × 10⁻⁶. 6 cfu / mL.

[0103] 2. Determination of protease production capacity of GD1 strain

[0104] Take 5 μL of the fermentation broth of strain GD1 prepared in step 1 and spot it onto the protease detection medium. Incubate at 28°C for 24 h and observe whether a transparent hydrolysis zone is formed.

[0105] See results Figure 4 ,from Figure 4 As can be seen, the GD1 strain can produce obvious transparent hydrolysis zones on the protease detection medium, and can produce transparent zones with a diameter of about 1.83±0.8cm in just 24 hours of culture, which proves that the Peach Bacillus pyrifolia GD1 strain has good protease production ability.

[0106] Example 3: Antibacterial effect of Paenibacillus taohuashanense GD1 strain

[0107] 1. Preparation of GD1 strain fermentation broth

[0108] The specific method is the same as that in Example 2.

[0109] 2. Determination of the bacteriostatic effect of GD1 strain

[0110] Common plant pathogens, i.e., Penicillium italicum, Cladosporium cladosporioides, Colletotrichum fructicola and Botrytis cinerea (laboratory isolated, identified and preserved) were used as indicator bacteria. Four-point confrontation method was used. The indicator bacteria were punched into a bacterial cake and placed for inoculation in the center of a PDA plate. The GD1 strain fermentation broth prepared in step 1 was dropped onto four points about 2.5 cm away from the bacterial cake, 5 μL of GD1 strain fermentation broth per point. The control group was dropped with the same amount of ddH2O, and three replicates were set. Cultured at 28°C until the control grew to 2 / 3 of the plate, the bacteriostatic condition and the size of the inhibition zone were observed. The colony diameter was recorded, and the bacteriostatic rate was calculated. The calculation formula of the bacteriostatic rate is as follows:

[0111] Bacteriostatic rate (%) = (control colony diameter - treatment colony diameter) / control colony diameter x 100%

[0112] The results are shown in Table 2, Figures 5-8 As can be seen from the figure, the GD1 strain has good inhibition effect on the four plant pathogenic fungi: Penicillium italicum, Cladosporium cladosporioides, Colletotrichum fructicola and Botrytis cinerea, with inhibition rates of 88% for Penicillium italicum, 72.77% for Cladosporium cladosporioides, 52.25% for Colletotrichum fructicola and 74.5% for Botrytis cinerea, indicating that the GD1 strain has good broad-spectrum bacteriostatic effect and can be used as a biocontrol agent for the prevention and control of plant diseases.

[0113] Table 2. Bacteriostatic effect of GD1 strain

[0114]

[0115] Example 4. Determination of the prevention and control effect of Paenibacillus taohuashanense GD1 strain

[0116] 1. Preparation of GD1 strain fermentation broth

[0117] The specific method is the same as in Example 2;

[0118] 2. Determination of the control effect of GD1 strain

[0119] (1) Take fresh tangerines, soak them in a 5% sodium hypochlorite solution for 1 minute, then rinse them three times with sterile water and air dry them naturally.

[0120] (2) Remove the stems from the disinfected mandarins, inoculate them with a 5mm mycelium cake of Penicillium italicum (same as in Example 3), cover the mycelium cake with sterile cotton, drip sterile water onto the cotton to keep it moist, place it in a 26℃ incubator, maintain humidity of 60-70%, and remove the cotton after 1 day.

[0121] (3) One control group and four treatment groups were set up. The control group was sprayed with water, while the treatment groups were sprayed with 2 mL of the original fermentation broth of GD1 strain (prepared in step (1)), 10-fold diluted fermentation broth of GD1 strain, 20-fold diluted fermentation broth of GD1 strain, and 50-fold diluted fermentation broth of GD1 strain, respectively. Three replicates were set up for each group. After 4 days, the incidence of disease in the treatment group and the control group was compared and photographed for statistical analysis.

[0122] Depend on Figure 9 It can be seen that the tangerines treated with water developed the disease normally, while those sprayed with the bacterial solution remained normal and showed no signs of disease. Therefore, the fermentation broth of strain GD1 has a strong control effect on citrus Penicillium rot, achieving a 100% control efficacy.

[0123] In summary, this invention has isolated a Paenibacillus taohuashanense GD1 strain, which exhibits good protease production capacity and can be used for plant growth promotion. Simultaneously, this strain also possesses broad-spectrum antibacterial activity, showing good inhibitory effects against various plant pathogenic fungi, such as Penicillium italicum, Cladosporium cladosporioides, Colletotrichum fructicola, and Botrytis cinerea, demonstrating significant inhibitory effects. This strain can be used as a biocontrol agent to prevent and control various plant diseases, enriching the strain resources of biocontrol agents.

[0124] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A type of Bacillus flavus ( Paenibacillus taohuashanense GD1, characterized in that, It was preserved in Guangdong Microbial Culture Collection Center on January 19, 2024, and the address is: No. 59 Building, 5th Floor, Guangzhou, Guangdong, China, and the preservation number is: GDMCC No 64296.

2. The application of the Paenibacillus taohuashanense and / or its fermentation liquor in the preparation of protease or the field of plant growth promotion according to claim 1.

3. The application of the Paenibacillus taohuashanense and / or its fermentation liquor in the field of inhibiting plant pathogenic fungi, preventing plant diseases caused by plant pathogenic fungi, or preparing plant pathogenic fungi inhibitors or biocontrol agents according to claim 1.

4. The application according to claim 3, wherein the plant is citrus.

5. The application according to claim 3, wherein the plant pathogenic fungi is Penicillium italicum, Cladosporium cladosporioides, Colletotrichum fructicola, or Botrytis cinerea. Penicillium italicum The plant pathogenic fungi are at least one of Penicillium italicum Cladosporium cladosporioides , Cladosporium cladosporioides Colletotrichum fructicola , Guignardia bidwellii Botrytis cinerea , and Botrytis cinerea The Paenibacillus taohuashanense and / or its fermentation liquor according to claim 1. .

6. A plant pathogen inhibitor or biocontrol agent, characterized in that The method comprises the following steps:

7. A method of controlling plant diseases, characterized by The plant is treated with the Paenibacillus taohuashanense and / or its fermentation liquor according to claim 1.

8. The method for preventing plant diseases according to claim 7, wherein the Paenibacillus taohuashanense fermentation liquor is prepared by the following steps: (1) The activated Paenibacillus taohuashanense is inoculated on LB solid medium and cultured at 28℃ until single colonies are formed; (2) The single colonies after step (1) are inoculated in LB liquid medium and cultured at 28℃ and 150-240 rpm to obtain seed liquid; (3) The seed liquid is added to LB liquid medium and cultured at 28℃ and 150-240 rpm to obtain Paenibacillus taohuashanense fermentation liquor.

9. The method for preventing plant diseases according to claim 7, wherein the treatment is spraying.

10. The method for preventing plant diseases according to claim 7, wherein the plant is citrus. ​ ​ ​ ​

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