Penicillium carmichaeli and application of penicillium carmichaeli in prevention and treatment of crop stem rot

Abstract

The invention discloses Penicillium carmichaeli and application thereof in prevention and control of crop stem rot, and belongs to the technical field of green prevention and control of crop diseases. According to the invention, a strain of Penicillium cameberti JK10 is separated from rhizosphere soil of crops, and the Penicillium cameberti JK10 has an obvious antagonistic effect on pathogenic bacteria, namely fusarium, of crop stem rot, has the properties of nitrogen fixation, potassium dissolution, phosphorus dissolution and siderophore production, and can be used as a novel green crop disease prevention and control preparation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of green prevention and control of crop diseases, and in particular to a strain of Penicillium camemberti and its application in the prevention and control of crop basal stem rot. BACKGROUND

[0002] Basal stem rot is one of the main diseases of the basal part of crops. The pathogenic fungi causing basal stem rot of crops mainly include Pseudocercospora graminicola (Cooke) Sacc. Fusarium pseudograminearum ), Fusarium graminearum (Schweinitz) Sacc. Fusarium graminearum ), Fusarium chlamydosporum (Wiltshire) Wiltshire Fusarium culmorum ), Fusarium oxysporum (Schlechtendahl) S. Ito Fusarium oxysporum ), Fusarium proliferatum (T. Matsum) Shirai et Hara Fusarium proliferatum ), Fusarium fujikuroi (Shirai) Wiltshire Fusarium fujikuroi ) and Fusarium moniliforme (Shirai) Wiltshire Fusarium verticillioides These pathogenic fungi cause basal stem rot on different crops with diverse symptom manifestations and damage characteristics, affecting the normal growth of crops, and even leading to the death of the whole plant when the disease is severe.

[0003] Current prevention and control measures for basal stem rot of crops include disease-resistant breeding, physical control, chemical control, etc. These prevention and control measures have the advantages of improving crop yield and quality, reducing crop resistance, improving crop natural defense ability, fast-acting, easy-to-use, etc. However, they also have limitations such as long breeding cycle, technical bottleneck, limited effect of disease and pest control, high agricultural residues of food, disease and pest resistance, environmental pollution, etc.

[0004] Microbiome can provide new resources and strategies for the prevention and control of soil-borne diseases. Microbiome is considered as the "second genome" of plants and animals, and has important significance for the "integrated health" of plants, animals and humans. Beneficial microorganisms can improve the immune and stress resistance of crops, inhibit the growth, reproduction and pathogenicity of pathogens, and the ecological control strategy based on microbiome regulation provides a new perspective, theory and technology for plant pathology research and practice.

[0005] Significant progress has been made in the research of microorganisms in inhibiting soil-borne diseases. Through in-depth analysis of the structure and function of soil microbiome, a large number of microbial resources with antagonistic ability have been found, such as Pseudomonas, Bacillus and Trichoderma, etc. These microorganisms can secrete antibacterial substances, compete for nutrients or induce plant systemic resistance, thereby effectively inhibiting the growth and reproduction of pathogenic fungi.

[0006] By optimizing the "colonization carrier" of microorganisms (such as biochar, vermiculite, etc. porous materials), the colonization ability of beneficial microorganisms in the rhizosphere and the surface of plants is improved, and the space and nutrients (such as carbon source, nitrogen source, iron ion, etc.) required for the survival of pathogenic bacteria are occupied. For example, Bacillus amyloliquefaciens is adsorbed on biochar and applied to soil, and the colonization amount of tomato rhizosphere can be increased by 2-3 times, and by competing for iron ions and carbohydrates, the inhibition rate of root rot is increased to more than 60%.

[0007] Screening to obtain microorganisms that can secrete specific metabolites to destroy the nutrient acquisition pathway of pathogenic bacteria. For example, some Pseudomonas can secrete siderophores (a strong iron chelator) to preferentially bind iron ions in the soil, causing pathogenic bacteria (such as Fusarium) that rely on iron ions for reproduction to be inhibited due to "iron deficiency"; some yeast can secrete glucosidase to decompose specific sugars that pathogenic bacteria rely on for survival, indirectly inhibiting their spread.

[0008] The pathogenicity of many pathogenic bacteria (such as toxin secretion, biofilm formation) depends on "quorum sensing" - through the secretion of signal molecules (such as acyl homoserine lactone, AHLs) to achieve bacterial population coordination. Some microorganisms (such as Bacillus, lactic acid bacteria) can produce "quorum sensing inhibitors" (such as AHL lactonase) to destroy the signal transmission of pathogenic bacteria. For example, Bacillus isolated from marine sediments can degrade the signal molecules of soft rot bacteria through the secretion of AHL lactonase, reducing the incidence of Chinese cabbage soft rot by more than 50%.

[0009] Currently, most biocontrol strains are bacterial antagonistic strains, and the resources of antagonistic fungal strains are relatively scarce, which to some extent limits the diversity of biological control strategies. There are significant differences between biocontrol fungi and biocontrol bacteria in the core mechanism of inhibiting plant pathogenic bacteria. The core mechanism of biocontrol bacteria is "direct inhibition" - producing high-concentration crude lipopeptide antibacterial substances to quickly destroy the hyphal structure of pathogenic bacteria and inhibit the growth of pathogenic bacteria; biocontrol fungi focus on "inducing plant resistance", and their mycelial colonization can continuously activate the phenylpropanoid metabolism and jasmonic acid / salicylic acid signaling pathway, thereby improving the antioxidant enzyme activity and root activity of the host, and blocking the invasion of pathogenic bacteria to the vascular bundle. Under disease stress, antagonistic fungi are superior to antagonistic bacteria in inhibiting bacteria, preventing diseases, activating plant immunity, restoring yield, and symbiotic nitrogen fixation, and show the synergistic advantages of "multiple mechanisms + efficient repair". Therefore, in the future, it is necessary to strengthen the resource excavation and application research of antagonistic fungal strains to enrich the means of biological control and improve the prevention and control effect of plant diseases. SUMMARY

[0010] In view of the above prior art, the purpose of the present application is to provide a strain of Penicillium kameperei and its application in preventing and treating stem base rot of crops.

[0011] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: In a first aspect, the present invention provides a strain of Penicillium carmenereum ( Penicillium camemberti JK10, this strain was deposited on November 12, 2025 at the China Center for Type Culture Collection (CCTCC, Wuhan University, Wuhan, China), with accession number CCTCC NO: M 20252528.

[0012] A second aspect of the present invention provides a microbial agent containing the aforementioned *Penicillium carmenereum* (…). Penicillium camemberti JK10.

[0013] Preferably, the bacterial agent contains Penicillium carmenereum ( Penicillium camemberti JK10 exists in the form of cultured live bacteria, bacterial suspension, or fermentation broth.

[0014] Furthermore, the bacterial suspension is prepared by the following method: Penicillium carmenereum ( Penicillium camemberti JK10 was inoculated into a solid fermentation medium and fermented at 25-28℃ for 6-8 days. Sterile water was added to the fermented system, filtered, centrifuged, the supernatant was discarded, and the system was resuspended in sterile water to prepare a bacterial suspension.

[0015] The solid fermentation medium is prepared as follows: Wheat bran, corn cob powder, and soybean meal were mixed in a weight ratio of 6:3:1 to obtain a mixture. KH2PO4, MgSO4·7H2O, and CaCO3 were added to the mixture and mixed evenly to obtain the basal culture medium. The amount of KH2PO4 added was 0.5% of the weight of the mixture, the amount of MgSO4·7H2O added was 0.1% of the weight of the mixture, and the amount of CaCO3 added was 0.5% of the weight of the mixture. The basal culture medium and water were mixed at a weight ratio of 1:(1.2-1.5), sterilized, and a solid fermentation culture medium was prepared.

[0016] A third aspect of the present invention provides the above-mentioned *Penicillium carmenereum* ( Penicillium camemberti JK10 or the inoculant can be used in the following (1) or (2): (1) Controlling stem rot in crops; (2) Prepare agents for preventing and controlling crop stem rot.

[0017] In the above applications, the crop stem base rot is caused by *Fusarium graminearum*, *Fusarium fusiforme*, *Fusarium graminearum*, *Fusarium equisetifolium*, or *Fusarium moniliforme*.

[0018] Preferably, the crop is wheat or corn.

[0019] In a fourth aspect, the present application provides a method for preventing and treating crop basal stem rot, comprising the following steps: A suspension of Penicillium camembertii (P. Penicillium camemberti ) JK10 is applied to the crop at the sowing and / or greening stage.

[0020] Preferably, the spore concentration of the suspension is 1×10 6 CFU / mL.

[0021] Preferably, the application amount of the suspension is 25 L / acre, and the suspension is applied with water.

[0022] The present application has the following beneficial effects: The present application isolates a strain of antagonistic fungus, Penicillium camembertii (P. Penicillium camemberti ) JK10, from the rhizosphere soil sample of a crop basal stem rot strain, which has broad-spectrum antibacterial activity and inhibits the pathogenic fungi of Fusarium pseudograminearum, Fusarium fujikuroi, Fusarium subglutinans, Fusarium graminearum, Fusarium equiseti and Fusarium moniliforme, and can be developed into a biocontrol agent for preventing and treating crop basal stem rot.

[0023] The Penicillium camembertii (P. Penicillium camemberti ) JK10 of the present application also has the functions of nitrogen fixation, phosphorus dissolution, potassium dissolution, and iron carrier production. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 : Morphology of JK10 strain.

[0025] Figure 2 : Plate antagonistic experiment of JK10 strain.

[0026] Figure 3 : Broad-spectrum antagonistic property of JK10 strain.

[0027] Figure 4 : Qualitative test of growth-promoting function of JK10 strain.

[0028] Figure 5 : Quantitative test of iron carrier production of JK10 strain.

[0029] Figure 6 : Effect of VOCs produced by JK10 strain on the growth of pathogenic fungi; a: two G14LY24-2 pathogenic fungi are cultured in a plate by plate culture; b: JK10 plate and G14LY24-2 plate are cultured in a plate by plate culture.

[0030] Figure 7 : Whole pot culture diagram and disease phenotype diagram of JK10 strain.

[0031] Figure 8JK10 strain potting biocontrol effect and growth promoting effect. DETAILED DESCRIPTION It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0032] In order to enable those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in combination with specific examples. If the specific conditions of the experiments are not specified in the examples, the specific conditions are generally in accordance with the conventional conditions or in accordance with the conditions recommended by the reagent company; the reagents, consumables, etc. used in the following examples, unless otherwise specified, can be obtained through commercial channels. Among them: Iron-limited MKB medium: take casein amino acid 5.0 g, glycerol 15 mL, deionized water 785 mL, mix evenly, get mixed solution A; take potassium phosphate dibasic 2.5 g, into 100 mL water, get mixed solution B; take magnesium sulfate heptahydrate 2.5 g, into 100 mL water, get mixed solution C. Mixed solution A, mixed solution B and mixed solution C are independently sterilized, 115℃, 30min, mix evenly when using, pH is about 7.0.

[0033] Iron-rich medium: add ferric chloride to the iron-limited MKB medium to make the concentration of ferric chloride 50 μmol / L.

[0034] CAS detection solution: A solution + B solution, mixed immediately before use. A solution: 0.0605 g chrome azurol S + 50 mL sterile water + 10 mL FeCl3.6H2O solution; B solution: 0.0729 g HDTMA (hexadecyl trimethyl ammonium bromide) + 40 mL sterile water. Mixed immediately before use, CAS detection solution is obtained.

[0035] Solid fermentation medium: mix bran, corncob powder and soybean meal according to the weight ratio of 6:3:1 to get mixed material; add KH2PO4, MgSO4·7H2O and CaCO3 to the mixed material and mix evenly to get the basic medium; the addition amount of KH2PO4 is 0.5% of the weight of the mixed material, the addition amount of MgSO4·7H2O is 0.1% of the weight of the mixed material, and the addition amount of CaCO3 is 0.5% of the weight of the mixed material; Mix the basic medium with water according to the weight ratio of 1:1.2, sterilize at 121℃ high pressure steam for 30 minutes to prepare the solid fermentation medium.

[0036] The pathogenic fungus used is Fusarium pseudograminearum (F. pseudograminearum) Fusarium pseudograminearum, G14LY24-2), a highly virulent strain preserved by the Plant Protection Institute of Henan Academy of Agricultural Sciences; F. fujikuroi, F. proliferatum, F. graminearum, F. equiseti, and F. verticillioides are all pathogenic fungi reported in the prior art and are available from the applicant for repeating the experiments.

[0037] Example 1: Isolation and screening of strains 1. Primary screening of strains Healthy and infected crop rhizosphere soil samples were collected from the Shandong Agricultural University Science and Technology Station in Taian, Shandong Province, China. 15 g of soil sample was added to a conical flask containing 135 mL of sterile water with glass beads, and shaken at 170-180 r / min for 60 min to fully disperse the soil sample. The soil sample was diluted in a 15 mL sterile centrifuge tube and mixed well using a shaker. Gradient dilution was performed to 1 x 10 -2 , 1 x 10 -3 , 1 x 10 -4 , 1 x 10 -5 After gradient dilution, 100 μL of 1 x 10 -3 , 1 x 10 -4 , 1 x 10 -5 was taken and plated on PDA medium (a general-purpose medium suitable for the basic growth of fungal strains) and a Bengal red medium (a selective medium) for general screening. Each gradient was repeated three times. The plates were incubated at 25-28°C for 3-5 days. Colonies with significant differences were selected according to the following criteria: (1) Color difference: colonies producing pigments or spores; (2) Size difference: quantification: colony diameter difference ≥ 5 mm at the same culture time; edge with fan-shaped mutation was directly single-columned new morphology, and no longer only diameter was considered. Morphological difference: mycelium morphology; (3) Morphological difference: macroscopically: mycelium radiation, ring, concentric ring, Fractal dimension difference ≥ 0.05; microscopically: mycelium spacing, branch angle difference > 20° under low-power lens (40x) was also counted; (4) Spore difference: quantification: 50 mature spores were randomly measured under 400x, and the length / width ratio difference ≥ 0.2, or the tip shape appeared crescent, sickle, shuttle, spherical, etc. "new contour", which was judged to be different. At the same time, the spore structure (bottle neck, sporodochium, sporangium) type was recorded.

[0038] The RGB value, elevation, and edge coefficient of each colony were recorded using ImageJ. Subsequently, only new morphologies with Euclidean distance > 0.35 were selected, and only one representative strain of the same morphology was kept. The strains were subcultured on PDA plates, numbered, and preserved at 4°C and -20°C for future use.

[0039] 2. Strain re-screening: The fungal strains with significant differences obtained by preliminary screening were subjected to re-screening, and the re-screening conditions were as follows: (1) Screening of strains with broad-spectrum antagonistic properties: The broad-spectrum antagonistic properties of the strains were verified, and other Fusarium pathogenic fungi and the target pathogenic fungus G14LY24-2 were selected as the sources of wheat basal stem rot disease to perform plate confrontation experiments, and the biocontrol fungal strains with broad-spectrum antagonistic ability were selected. Selection criteria: PDA medium was used, the fungal strains to be screened and each pathogenic fungus were prepared into 5 mm diameter fungus cakes, inoculated according to the method of “pathogenic fungus cake in the middle, and fungus cake of strain to be screened 3 cm away from it”, incubated at 25°C in the dark for 7 days, the inhibition rate of pathogenic fungus colony expansion was determined (inhibition rate = (control colony diameter - treated colony diameter) / control colony diameter x 100%), and the broad-spectrum antagonistic strains with inhibition rate ≥ 60% against 3 or more pathogenic fungi were selected.

[0040] (2) Screening of strains with growth-promoting function Qualitative experiments of strain growth-promoting function (nitrogen fixation, phosphorus dissolution, potassium dissolution, and iron carrier production) were performed, and the biocontrol fungi with growth-promoting function were selected. Nitrogen fixation function: inoculated into Ashby nitrogen fixation medium, incubated at 28°C for 4 days, and the strain was positive for nitrogen fixation if it could grow; Phosphorus dissolution function: inoculated into inorganic phosphorus medium (containing insoluble calcium phosphate), incubated at 28°C for 4 days, and the strain was positive for phosphorus dissolution if the colony grew normally or a transparent circle appeared around it; Potassium dissolution function: inoculated into silicate bacteria medium (containing potassium feldspar), incubated at 28°C for 4 days, and the strain was positive for potassium dissolution if the colony grew normally or a transparent circle appeared around it; Iron carrier production: inoculated into CAS blue detection plate, incubated at 28°C for 4 days, and the strain was positive for iron carrier production if an orange halo appeared around the colony; Strains with at least two or more growth-promoting functions were selected for the next step of screening.

[0041] From the strains with both broad-spectrum antagonistic properties and at least two growth-promoting properties, the strain JK10 with the highest inhibition rate against G14LY24-2 was selected as the target strain.

[0042] Example 2: Identification of strain JK10 1. Morphological identification of strain JK10: Strain JK10 was inoculated on PDA medium containing streptomycin and Bengal red medium, and incubated at 25°C for 5 days, and the color and texture characteristics of the colony were observed. The results are shown in Table 1. Figure 1As shown, the JK10 strain grows slowly on PDA medium, initially white, gradually turning into gray-green, with the back side being light yellow to yellow-brown, and the colony texture being fluffy or flocculent.

[0043] 2. Molecular biological identification of strain JK10: Genomic DNA of strain JK10 was extracted, and universal primers ITS1 and ITS4 were used for PCR amplification, ITS1: 5'-TCCGTAGGTGAACCTGCGG-3' and ITS4: 5'-TCCTCCGCTTATTGATATGC-3', and the PCR amplification system (25 μL) included: Taq enzyme 12.5 μL, ddH2O 9.5 μL, 1 μL of forward and reverse primers, 1 μL of template DNA; the PCR amplification program was: 94°C pre-denaturation for 2 min, 94°C denaturation for 30 s, 55°C annealing for 30 s, 72°C extension for 30 s, 35 cycles; 72°C final extension for 2 min, 4°C termination reaction. After the PCR product was detected by 1% agarose gel electrophoresis, it was sent to Shengong Bioengineering (Shanghai) Co., Ltd. for sequencing, and the sequence is shown as SEQ ID NO. 1. The obtained sequence result was submitted to the GenBank gene library of the National Center of Biotechnology Information (NCBI) for basic local alignment search tool (BLAST) retrieval. After alignment, the similarity with Penicillium camemberti (P. camemberti) was 99.83%. Penicillium camemberti

[0044] Based on the results of morphological, physiological and biochemical identification and molecular biological identification of the strain, strain JK10 was identified as Penicillium camemberti (P. camemberti), and biological preservation was carried out for the patent procedure, and the preservation information is as follows: Penicillium camemberti Biological material (strain) used for reference: JK10; Suggested classification name: Penicillium camemberti (P. camemberti); Preservation number: CCTCC NO: M 20252528. Penicillium camemberti

[0045] Example 3: Investigation of the antibacterial performance of Penicillium camemberti JK10 1. Investigation of the antibacterial performance on Fusarium pseudograminearum G14LY24-2: Penicillium camemberti JK10 and pathogenic bacteria (Fusarium pseudograminearum G14LY24-2) stored at 4°C were taken. Fusarium pseudograminearum ​​​(G14LY24-2) Mycelia were picked up with sterile toothpicks and placed on PDA medium to activate the strains. After culturing for 4-5 days until colonies of a certain size were formed, mycelial cakes were made in equal proportions using a sterile punch. The pathogenic mycelial cakes were placed in the center of a new PDA plate, and the fungal mycelial cakes were placed symmetrically upside down, 2 cm away from the pathogenic mycelial cakes. The pathogenic mycelial cakes were placed upside down in the center of the PDA plate as a control group. After culturing for 3-5 days, the size of the pathogenic colonies was observed. The fungal culture dishes were placed in an incubator at 28℃±0.5℃ and 75% relative humidity, and the growth of the pathogens was observed regularly, recording changes in colony size, morphology, and color.

[0046] Figure 2 The image shown is a typical photograph of JK10 and Fusarium graminearum G14LY24-2 on a PDA plate after 8 days of confrontation. The biocontrol fungus JK10 showed a significant inhibitory effect on Fusarium graminearum G14LY24-2, resulting in the following changes in the size, morphology, and color of G14LY24-2 colonies: Colony size changes: In the control group G14LY24-2 (without JK10), colonies expanded rapidly, with an average diameter of 78 mm after 7 days, almost covering the entire plate. In the JK10 treatment group, the growth of G14LY24-2 colonies was restricted, with an average diameter of only 18 mm, an inhibition rate of 77%, and a significant slowdown in edge expansion.

[0047] Colony morphology changes: CK showed regular radial circles at the edges; JK10 treatment showed serrated edges, significantly sparse hyphae, and a 2–3 mm transparent inhibition zone.

[0048] Colony color changes: In the control group, the reverse side of G14LY24-2 colonies was pale yellow or pale purple, and G14LY24-2 showed obvious pigment secretion. In the JK10 treatment group, the pigment secretion of G14LY24-2 decreased, and the pigment ring on the reverse side weakened, indicating that its metabolic activity was inhibited.

[0049] 2. Evaluation of antibacterial properties against other pathogens: Stem base rot is caused by various Fusarium species ( Fusarium The study investigated the antibacterial properties of Penicillium carmenere JK10 against other pathogens, focusing on soil-borne diseases caused by single or combined infections (spp.).

[0050] The results are as follows Figure 3 As shown, the results indicate that the JK10 biocontrol fungus is effective against Fusarium oxysporum (Fusarium oxysporum). Fusarium fujikuroi ,Ff), laminaria ( Fusarium proliferatum Fusarium graminearum ( ), Fusarium graminearum Fg), Fusarium equisetifolium ( Fusarium equiseti Fe), Fusarium moniliforme ( Fusarium verticillioides, Fv) can significantly inhibit the growth of pathogenic bacteria, which proves that JK10 has broad-spectrum antagonistic properties.

[0051] Example 4: Investigation on the growth-promoting properties of Penicillium camembertii JK10 1. Test method: (1) Investigation on nitrogen fixation ability: Penicillium camembertii JK10 was cultured on nitrogen-free medium (Ashby medium) for 3-5 days, and the growth of the strain was observed.

[0052] (2) Investigation on phosphorus solubilization ability: Penicillium camembertii JK10 was inoculated on inorganic iron phosphate medium (purchased from Qingdao High-tech Industrial Park Haibo Biotechnology Co., Ltd., product number: HB8670-2) for culture to investigate whether the strain has the ability to dissolve inorganic phosphorus.

[0053] (3) Investigation on potassium solubilization ability: Penicillium camembertii JK10 was inoculated on silicate medium for culture to investigate whether the strain has the ability to dissolve potassium.

[0054] (4) Investigation on siderophore production ability: ① Qualitative investigation: Penicillium camembertii JK10 was inoculated on CAS medium for culture to investigate whether the strain has the ability to produce siderophores.

[0055] ② Quantitative investigation: Under sterile conditions, sterile toothpicks were used to pick JK10 biocontrol fungal mycelium and add it to iron-limited MKB medium and iron-rich medium, and cultured at 28°C and 180 r / min for 3-5 days. The supernatant was obtained by centrifugation at 8000 r / min for 10 min. 100 μL of the strain supernatant was added to 100 μL of mixed CAS detection solution, and the mixture was dark-treated for 30 min. The absorbance was measured at OD 630nm , and the amount of siderophores produced by JK10 strain was calculated according to the following formula: Su= (Ar-As) / Ar x 100%.

[0056] Ar: represents the absorbance value of the control group (or blank group); As represents the absorbance value of the experimental group (iron deficiency condition).

[0057] Ar is "iron-limited MKB blank medium without inoculation of the strain", which is used for CAS method background zero correction; As is "iron-limited culture supernatant inoculated with JK10 strain", and the difference between the two reflects the amount of siderophores produced.

[0058] 2. Test results: The results of qualitative investigation of Penicillium camembertii JK10 for nitrogen fixation, phosphorus dissolution, potassium dissolution and siderophore production are shown in Table 1. Figure 4 As shown in Table 1, after culturing Penicillium camembertii JK10 in CAS medium, a double halo of blue and orange was formed around the colony, with the outer ring being orange and the inner ring being blue, proving that it has the ability to produce siderophores; Penicillium camembertii JK10 can grow normally in nitrogen-free medium, proving that it has the ability of nitrogen fixation; Penicillium camembertii JK10 can grow normally and produce a transparent circle in inorganic iron phosphate medium, proving that it has the ability to dissolve phosphorus; Penicillium camembertii JK10 can grow normally or produce a transparent circle in silicate medium, proving that it has the ability to dissolve potassium.

[0059] Through quantitative determination, the siderophore production capacity of JK10 strain can reach 78.25% (w / w). Figure 5

[0060] Example 5: Investigation of the antibacterial effect of volatile organic compounds (VOCs) produced by Penicillium camembertii JK10 on Fusarium pseudograminearum 1. Test method: The plate pairing method of biocontrol fungi and pathogenic fungi is used to verify the inhibition effect of volatile organic compounds (VOCs) produced by biocontrol fungi on the growth of pathogenic fungi, which is a direct and effective method.

[0061] Penicillium camembertii JK10 and pathogenic fungi (Fusarium pseudograminearum G14LY24-2) were cultured on potato dextrose agar (PDA) medium until obvious colonies were formed. In a sterile table, a puncher was used to punch the pathogenic fungi, and the fungus cake was taken to a new potato dextrose agar (PDA) medium. The biocontrol fungi (equidistant streaking method) were inverted to make them in close contact with the biocontrol fungi culture dish, but not directly touching, to allow the transmission of VOCs. The two culture dishes were sealed with sealing film to prevent external contamination and escape of VOCs. The paired culture dishes were placed in a 28℃±0.5℃, 75% relative humidity incubator for culture, and the growth of pathogenic fungi was observed regularly. The size, shape and color changes of the colonies were recorded. After 7 days of culture, the growth inhibition rate of JK10 strain VOCs on pathogenic fungi G14LY24-2 was calculated.

[0062] Inhibition rate (%) = [(D_ck-D_treat) / D_ck] x 100; where D_ck is the colony diameter of the control group, and D_treat is the colony diameter of the treatment group.

[0063] 2. Test results: The results are shown in Table 2. Figure 6 ​As shown, the pathogenic bacteria G14LY24-2 grew to a diameter of 90 mm on the 10th day, and the JK10 plate and the G14LY24-2 plate were cultured against each other to the 10th day, and the pathogenic bacteria grew to a diameter of 10 mm. By the radius calculation method, the average inhibition rate of the VOCs produced by JK10 on 14LY24-2 reached 88.9%.

[0064] Example 6: Pot experiment 1. Test method: (1) Preparation of Penicillium camembertii JK10 spore suspension: 10 mL of Penicillium camembertii JK10 was inoculated into 50 g of solid fermentation medium and cultured in a constant temperature incubator at 25°C for 7 days. 500 mL of sterile water was added to the fermented system, filtered through three layers of sterile gauze, and centrifuged in a high-speed centrifuge (4°C, 8000 r / min, 10 min). The supernatant was discarded, and the spores were resuspended with sterile water. The OD value of the spore suspension was adjusted to about 0.3 using a UV spectrophotometer, and the viable spore count was about 1×10 6 CFU / mL.

[0065] (2) Pot planting: Wheat susceptible variety 'Jimai 22' was used as test material, and three treatment groups were set up as follows: Treatment 1 (CK): 32-hole pots were used, each hole was filled with 130 g of soil, and 10 mL of sterile water was inoculated into each hole. After incubating the soil for 5 days, the germinated Jimai 22 seeds were transplanted, and 10 mL of sterile water was irrigated on the 7th and 14th days of wheat growth.

[0066] Treatment 2 (G14LY24-2): 32-hole pots were used, each hole was filled with 130 g of soil, and 10 mL of sterile water was inoculated into each hole. After incubating the soil for 5 days, the germinated Jimai 22 seeds were transplanted, and 10 mL of spore suspension of the pathogenic bacteria (Fusarium pseudograminearum G14LY24-2) with a viable spore count of about 1×10 6 CFU / mL was inoculated on the 7th day of wheat growth, and 10 mL of spore suspension of the pathogenic bacteria (Fusarium pseudograminearum G14LY24-2) with a viable spore count of about 1×10 6 CFU / mL was inoculated again on the 14th day of wheat growth.

[0067] Treatment 3 (JK10): 32-hole pots were used, each hole was filled with 130 g of soil, and 10 mL of Penicillium camembertii JK10 spore suspension was inoculated into each hole. After incubating the soil for 5 days, the germinated Jimai 22 seeds were transplanted, and 10 mL of spore suspension of the pathogenic bacteria (Fusarium pseudograminearum G14LY24-2) with a viable spore count of about 1×106 CFU / mL) 10 mL, and the wheat was inoculated again with a spore suspension of the pathogenic fungus (Fusarium pseudograminearum G14LY24-2) (about 1 x 10 6 CFU / mL) 10 mL.

[0068] On the 21st day after the first inoculation of the pathogenic fungus, the wheat was observed for disease, and on the 40th day, the disease grade, lesion length, and biomass (plant height, total fresh weight, and aboveground fresh weight) of the wheat in each treatment were counted.

[0069] The wheat was divided into 0 grade (no obvious symptoms), 1 grade (obvious necrotic spots on the coleoptile sheath or the first leaf sheath), 2 grade (partial necrosis of the first leaf sheath and underground stem), 3 grade (complete necrosis of the second leaf sheath and underground stem, accompanied by clear shortening, not more than one-half of the height of the plant or seedling), 4 grade (partial or complete necrosis of the third leaf or leaf sheath and underground stem, accompanied by severe shortening more than one-half of the height of the plant or seedling), and 5 grade (severe necrosis of the entire plant to safe necrosis) according to the severity of the disease.

[0070] 2. Test results: The results are shown in Table 1. Figures 7-8 As shown in Table 1, compared with the treatment of only inoculating the pathogenic fungus G14LY24-2, the biocontrol fungus JK10 significantly reduced the disease grade (P < 0.05) and necrosis length (P < 0.01) of the wheat foot rot. In addition, under the stress of the pathogenic fungus, JK10 treatment effectively alleviated the inhibition of the pathogenic fungus G14LY24-2 on the growth of the wheat, and the plant height, total fresh weight, and aboveground fresh weight were significantly increased (P < 0.05), indicating that JK10 can induce systemic resistance and promote plant growth, thereby reducing the toxic effects of the pathogenic fungus on the wheat.

[0071] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A strain of Penicillium carmenereum ( Penicillium camemberti JK10, its accession number is: CCTCC NO: M20252528.

2. An inoculant characterized in that, The bacterial agent contains the Penicillium camembertii of claim 1 Penicillium camemberti ) JK10.

3. The bacterial agent of claim 2, wherein The bacterial agent, Penicillium camembertii (P. Penicillium camemberti ) JK10 exists in the form of a live bacterium, a bacterial suspension or a fermentation broth.

4. The bacterial agent of claim 3, characterized in that, The bacterial suspension is prepared by the following method: Penicillium camembertii (P. Penicillium camemberti ) JK10 was inoculated into solid fermentation medium and fermented at 25-28°C for 6-8 days. Sterile water was added to the system after fermentation, filtered, centrifuged, the supernatant was discarded, and the bacterial suspension was prepared by resuspending with sterile water.

5. The bacterial agent of claim 4, characterized in that, The preparation method of the solid fermentation medium is as follows: The bran, corn cob powder and soybean meal are mixed according to the weight ratio of 6:3:1 to obtain a mixture; KH2PO4, MgSO4·7H2O and CaCO3 are added into the mixture and mixed uniformly to obtain a basic medium; the addition amount of KH2PO4 is 0.5% of the weight of the mixture, the addition amount of MgSO4·7H2O is 0.1% of the weight of the mixture, and the addition amount of CaCO3 is 0.5% of the weight of the mixture; The basic medium is mixed with water according to the weight ratio of 1: (1.2-1.5), sterilized to prepare the solid fermentation medium.

6. The strain of Penicillium camembertii (P. camembertii) JK10 of claim 1 or the inoculant of any one of claims 2 to 4 for use in (1) or (2) below. Penicillium camemberti ) (1) preventing and treating crop basal stem rot; (2) preparing a medicament for preventing and treating crop basal stem rot.

7. Use according to claim 6, characterized in that, The crop basal stem rot is caused by Fusarium.

8. A method of controlling seedling blight of crops, characterized by, The method comprises the following steps: A bacterial suspension of Penicillium camembertii (P. Penicillium camemberti ) JK10 is applied at the time of sowing and / or at the time of regrowth of the crop.

9. The method of claim 8, wherein, The spore concentration of the bacterial suspension was 1 x 10 6 CFU / mL.

10. The method of claim 8, wherein, The application amount of the bacterial suspension is 25L / acre, and the bacterial suspension is applied with water.

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