Kitasatospora xanthocidica jy01 strain and application thereof

Abstract

The present application provides Kitasatospora xanthocidica The JY01 strain and its application, the strain is isolated from the spring silkworm intestinal tract, has good disease resistance and growth promotion effect, specifically, can secrete cellulase and beta-1, 3-glucanase, produce siderophore and auxin IAA, through potting test, the biocontrol efficiency of the bacterial agent on wheat stem base rot is 57.90%, the biocontrol efficiency of the bacterial agent on corn stem base rot is 46.41%, and the plant height and fresh weight are significantly improved, the bacterial agent is expected to be applied to prepare biological bacterial fertilizer to effectively prevent and control the occurrence of soil-borne fungal diseases.

Description

Technical Field

[0001] This invention relates to the field of microbial technology, specifically to... Kitasatospora xanthocidica JY01 strain and its application. Background Technology

[0002] Soil-borne fungal diseases pose a significant threat to global agricultural production, as their soil-borne transmission leads to frequent cropping obstacles. Fusarium (Fusarium tumefaciens) is a prime example. Fusarium Pathogens such as carbendazim and thiophanate-methyl can cause severe diseases like corn stem rot and wheat stem rot, leading to reduced yields or even crop failure. Traditional control methods mainly rely on chemical pesticides, such as carbendazim and thiophanate-methyl, but long-term use has caused serious problems: on the one hand, chemical pesticides have a residual period in the soil of 3-5 years, leading to groundwater pollution and soil microbial imbalance; on the other hand, pathogen resistance is increasing year by year. Therefore, while the use of chemical pesticides may be effective in the short term, it easily leads to environmental pollution and pathogen resistance, thus urgently requiring environmentally friendly alternative technologies.

[0003] Actinomycetes are an important group of soil microorganisms and play a vital role in the prevention and control of soil-borne diseases. Their mechanism of action mainly involves inhibiting the growth of pathogens by secreting antagonistic substances, regulating the soil microbial flora, and improving the microbial community structure.

[0004] While biological control technology is considered a direction for green pest control, existing antagonistic fungal agents face significant technical bottlenecks. Currently commercially available Trichoderma agents have limited inhibitory rates against Fusarium and primarily target single pathogens, making them inadequate for dealing with multi-infection scenarios. More seriously, most antagonistic strains lack growth-promoting functions. Summary of the Invention

[0005] In view of the above, it is especially important to screen for actinomycetes with high inhibition rates against soil-borne pathogenic fungi, and to develop these fungi into biological agents that can not only effectively control soil-borne diseases caused by the Fusarium genus but also promote the growth of corn or wheat. In order to solve the above technical problems, the present invention adopts the following technical solution.

[0006] This invention screened out a plant Kitasatospora xanthocidica strain JY01, its classification name is Kitasatospora xanthocidica The strain has the accession number CGMCC NO.34740 and is deposited at the China General Microbiological Culture Collection Center, located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing. The deposit date is June 3, 2025.

[0007] The present invention also provides a method comprising the method described in claim 1. Kitasatospora xanthocidica JY01 bacterial agent.

[0008] The application also provides a use of the JY01 strain or the microbial agent as described above in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases. Kitasatospora xanthocidica The application also provides a use of the JY01 strain or the microbial agent as described above in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases.

[0009] The application further discloses that the pathogenic bacteria of the soil-borne fungal diseases are Fusarium oxysporum Fusarium oxysporum ), Pseudocercosporella herpotrichoides Fusarium pseudograminearum ) and / or Colletotrichum Colletotrichum capsica .

[0010] The application further discloses that the soil-borne fungal diseases are wheat basal stem rot, pepper anthracnose, soybean root rot, cucumber fusarium wilt and / or corn basal stem rot.

[0011] The application also provides a use of the JY01 strain or the microbial agent as described above in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases. Kitasatospora xanthocidica The application also provides a use of the JY01 strain or the microbial agent as described above in promoting the growth of corn or wheat.

[0012] The application also provides a use of the JY01 strain or the microbial agent as described above in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases. Kitasatospora xanthocidica The application also provides a use of the JY01 strain or the microbial agent as described above in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases.

[0013] The application also provides a use of the JY01 strain or the microbial agent as described above in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases. Kitasatospora xanthocidica The application also provides a use of the JY01 strain or the microbial agent as described above in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases. Kitasatospora xanthocidica The application also provides a use of the JY01 strain or the microbial agent as described above in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases.

[0014] The application also provides a use of the JY01 strain or the microbial agent as described above in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases. Kitasatospora xanthocidica The application also provides a use of the JY01 strain or the microbial agent as described above in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases. Kitasatospora xanthocidica The application also provides a use of the JY01 strain or the microbial agent as described above in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases.

[0015] The application also provides a use of the JY01 strain or the microbial agent as described above in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases. Kitasatospora xanthocidica The application also provides a use of the JY01 strain or the microbial agent as described above in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases.

[0016] Therefore, the application has the following beneficial effects:

[0017] The JY01 strain screened by the application Kitasatospora xanthocidicaThe JY01 strain exhibits broad-spectrum antagonistic activity against soil-borne fungal diseases of wheat foot rot, pepper anthracnose, soybean root rot, cucumber fusarium wilt and / or corn foot rot, breaking through the limitations of single pathogen prevention and control of existing biocontrol strains. The study also found that the JY01 strain can produce cellulase, beta-1, 3-glucanase, produce siderophores, and at the same time can produce IAA growth-promoting hormones to promote the growth of corn and wheat. Therefore, the JY01 strain has the dual functions of disease prevention and growth promotion. The pot experiment proves that the JY01 strain has a significant effect on wheat foot rot and / or corn foot rot, and has a good growth-promoting effect on plants, especially wheat and corn. The present application also converts agricultural waste into a production material for bacterial agent, using wheat bran (25%), silkworm excrement (40%), corn starch (20%) and soybean meal (15%) as the fermentation substrate, and the material to water ratio is 1:0.8. After shallow plate fermentation (28-30℃, 7-10 days), a stable bacterial agent with a spore content of ≥10 9 The present application opens up a new green and environmentally friendly way to solve the pollution of silkworm excrement and other wastes. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 Figure 1 is the inhibition effect of the strain JY01 of the present application on pathogenic fungi; wherein A: wheat foot rot pathogen; B: pepper anthracnose pathogen; C: soybean root rot pathogen; D: cucumber fusarium wilt pathogen.

[0019] Figure 2 Figure 2 is the colony morphology diagram of the strain JY01 of the present application; wherein A: spore filament morphology of strain JY01 under optical microscope; B: spore filament morphology of strain JY01 under scanning electron microscope; C: colony plate morphology of strain JY01.

[0020] Figure 3 Figure 3 is the phylogenetic tree diagram of the strain JY01 of the present application based on 16S rRNA sequence.

[0021] Figure 4 Figure 4 is the hydrolysis circle diagram of the strain JY01 of the present application formed on the cellulose Congo red culture medium.

[0022] Figure 5 Figure 5 is the hydrolysis circle diagram of the strain JY01 of the present application formed on the beta-1, 3-glucanase detection culture medium.

[0023] Figure 6 Figure 6 is the hydrolysis circle diagram of the strain JY01 of the present application formed on the CAS detection culture medium (siderophore detection culture medium).

[0024] Figure 7Qualitative experiment results of IAA produced by the strain JY01 of the present application (color change of reaction solution); wherein CK is the color presented after the reaction of the uninfected TSB culture solution with an equal volume of Salkowski colorimetric solution, and JY01 is the color presented after the reaction of the supernatant of the strain JY01 after TSB culture with an equal volume of Salkowski colorimetric solution.

[0025] Figure 8 Prevention and control effect diagram of the strain JY01 of the present application on wheat basal stem rot; wherein CK is the blank control treatment; Fp is the pathogenic fungus-Pseudocercosporella herpotrichoides treatment; and Fp+JY01 is the Pseudocercosporella herpotrichoides+JY01 solid biocontrol agent treatment.

[0026] Figure 9 Enlargement effect diagram of the prevention and control of the strain JY01 of the present application on wheat basal stem rot on the roots and stems of wheat; wherein (a) is the roots and stems of wheat inoculated with Pseudocercosporella herpotrichoides, and (b) is the roots and stems of wheat inoculated with Pseudocercosporella herpotrichoides after the seed treatment with the solid biocontrol agent of the strain JY01.

[0027] Figure 10 Prevention and control effect diagram of the strain JY01 of the present application on corn basal stem rot; wherein CK is the blank control treatment; Fo is the pathogenic fungus-Fusarium oxysporum treatment; and Fo+JY01 is the Fusarium oxysporum+JY01 solid biocontrol agent treatment. DETAILED DESCRIPTION

[0028] All features disclosed in this specification, and / or all steps of any method or process so disclosed, can be combined in any combination, except combinations where at least some of the features and / or steps are mutually exclusive.

[0029] Any feature disclosed in this specification, unless stated otherwise, can be replaced by any feature providing the same, or substantially the same, or equivalent functionality.

[0030] The culture medium, medicaments and instruments involved in the present experiment can be purchased on the market. Example 1

[0031] This example is Kitasatospora xanthocidica Screening, identification and biological characteristics of the strain JY01.

[0032] 1. Strain screening and antagonistic spectrum determination: 50 spring silkworm 4th instar larvae were collected from Huangshan in Anhui, Rugao in Jiangsu and Lishui in Zhejiang, starved overnight, and the body surface was disinfected with sterile water and 75% ethanol, and then immersed in 75% ethanol for 3 min, washed with sterile water for 3-5 times, dissected on a clean bench to obtain the intestinal tract of the silkworm larvae, grinded in a sterile mortar with a small amount of sterile water to obtain a homogenate, and then 100 μL of the homogenate was taken into 900 μL of sterile water, serially diluted to 10 -5Select 10 -3 10 -4 10 -5 Three dilutions were plated on Gao's No. 1 medium plates and incubated upside down at 30°C for 5-7 days. Single colonies of actinomycetes were picked, streaked on Gao's No. 1 medium plates for purification, and the obtained single colonies were transferred to slant culture and stored at 4°C.

[0033] The Gao's No. 1 culture medium contains the following components: 20g soluble starch, 1.0g KNO3, 0.5g K2HPO4·7H2O, 0.5g MgSO4·7H2O, 0.5g NaCl, 0.01g FeSO4·7H2O, 20g agar, 1000mL deionized water, and pH 7.2.

[0034] Antagonistic strains were screened using the plate confrontation method. Fresh slant agar of well-cultured actinomycetes was added with a small amount of sterile water to prepare a spore suspension. 100 μL of the spore suspension was spread onto a Gao Shi No. 1 plate and incubated at 30℃ for 5-7 days. Once the spores were fully developed, the actinomycete mycelial cake was extracted using a 5 mm punch. The pathogen of cucumber wilt (… Fusarium oxysporum f. sp. cucumerinum), soybean root rot pathogen ( Fusarium oxysporum f. sp . soybean), pepper anthracnose pathogen ( Colletotrichum capsica f. sp. chili), the pathogen of wheat stem rot (sp. chili), Fusarium pseudograminearum f. sp. wheat), rice bakanae disease pathogen (Fusarium fujikuroi ), the pathogen of corn stalk rot ( Fusarium oxysporum f. sp . Corn mycelium was placed in the center of a PDA plate, and an actinomycete mycelium was placed symmetrically on each side at a distance of 2 cm from the corn mycelium. The plates were incubated at 30℃ for 5-7 days, with three replicates per group. The inhibition rate was calculated to screen for actinomycete strains with strong antagonistic ability. The inhibition results obtained from the antagonistic experiment are shown in Table 1 below.

[0035] Inhibition rate (%) = (Coronavirus colony diameter in control group - Coronavirus colony diameter in treatment group) / (Coronavirus colony diameter in control group) × 100%.

[0036] Twenty actinomycete strains were obtained from the silkworm gut through screening, among which five strains exhibited antagonistic activity. Strain JY01 (originating from the spring silkworm breeding area of ​​Lishui City, Zhejiang Province) showed rapid growth, abundant conidia, a broad antibacterial spectrum, and strong antagonistic effects. Its plate confrontation culture with wheat stem rot pathogens showed significant effects (see...). Figure 1 ).

[0037]

[0038] From Table 1, the inhibition rate of strain JY01 on the pathogen of wheat basal stem rot reached 59.29%, and the inhibition rates on the pathogen of pepper anthracnose, soybean root rot, cucumber fusarium wilt and corn basal stem rot were all more than 60%. However, it had no obvious antagonistic effect on the pathogen of rice sheath blight. The strain JY01 had no obvious antagonistic effect on plant pathogenic bacteria, such as Pseudomonas solanacearum which caused tomato, pepper, eggplant and other solanaceous crops.

[0039] 2. Identification of antagonistic actinomycete JY01.

[0040] (1) Observation of morphological characteristics of antagonistic actinomycete JY01: On Gao's No. 1 medium, the colony color of JY01 was grayish white, and the aerial mycelium was grayish white (Fig. 1). Figure 2 The strain JY01 was streaked on Gao's No. 1 medium, and the sterilized cover glass was inserted into the plate at an angle of 45 degrees. After 5 days of culture at 30℃, the cover glass was taken out with tweezers, and the spore filament of the antagonistic strain JY01 was observed by scanning electron microscopy. The spore filament was straight, the spore surface was rough, and the conidium was columnar.

[0041] (2) Physiological and biochemical characteristics of antagonistic actinomycete JY01 are shown in Table 2: The results of 4-30 d physicochemical property determination of strain JY01 on gelatin liquefaction, milk peptonization, starch hydrolysis, cellulose decomposition, Czapek agar and carbon and nitrogen source utilization medium showed that strain JY01 could hydrolyze starch, liquefy gelatin, produce hydrogen sulfide, decompose cellulose, and utilize D-arabinose, D-xylose, D-raffinose, rhamnose, glucose and inositol as carbon sources, and utilize serine, glutamic acid, tyrosine and aspartic acid as nitrogen sources.

[0042]

[0043] (3) Molecular biology identification of antagonistic actinomycete JY01: The strain JY01 was sent to Shanghai Ling'en Biological Technology Co., Ltd. for 16S rRNA sequencing. The sequencing results were analyzed by BLAST comparison of related sequences using EzBioCloud platform. After sequencing, the JY01 gene sequence of 1397 bp was obtained, which was registered in NCBI (accession number PQ459648) for sequence comparison. The first 9 effective strain sequences with higher homology with JY01 were selected. The MEGA 11.0 software was used to construct a phylogenetic tree by the neighbour-joining (NJ) method, and the results showed that the homology of strain JY01 with Micropolyspora rosea reached 99.71%. Kitasatospora xanthocidica Figure 3 ), and combined with the morphology, physiological and biochemical indexes of the strain, the actinomycete JY01 was preliminarily identified as Kitasatospora xanthocidica . ​

[0044] The present applicant has found Kitasatospora xanthocidica The JY01 strain is preserved in the China General Microbiological Culture Collection Center, with a preservation number of CGMCC NO. 34740, a preservation address of No. 3, Beichen West Road, Chaoyang District, Beijing, and a preservation date of June 3, 2025. Example 2

[0045] This example is Kitasatospora xanthocidica Research on cellulase and β-1,3-glucanase production capacity of JY01 strain.

[0046] Carbohydrate active enzyme (CAZymes) activity measurement, including cellulase and β-1,3-glucanase. Spores of strain JY01 were inoculated into 100 mL of liquid TSB medium and cultured at 28°C, 180 rpm for 7 days, centrifuged at 8000 rpm for 10 minutes, and the supernatant was used for quantitative determination of enzyme activity. Cellulase and β-1,3-glucanase activities were determined using cellulase activity detection kit (Suzhou Keming Biotechnology Co., Ltd.) and β-1,3-glucanase kit (Suzhou Keming Biotechnology Co., Ltd.), respectively. One unit of cellulase activity is defined as 1 μg of glucose produced per minute per milliliter of sample solution at 37°C. One unit of β-1,3-glucanase activity is defined as 1 mg of reducing sugar produced per hour per milliliter of sample solution at 37°C. All experiments were repeated three times.

[0047] The β-1,3-glucanase detection medium includes the following components: glucan 5.0 g, NaNO3 2.0 g, K2HPO4 1.0 g, KCl 0.5 g, MgSO4·7H2O 0.5 g, FeSO4·7H2O 0.01 g, Congo red 0.05 g, agar 20 g, distilled water 1000 mL, 121°C sterilization for 20 min.

[0048] The cellulase detection medium includes the following components: (NH4)2SO4 2.0 g, K2HPO4 1.0 g, MgSO4·7H2O 0.5 g, NaCl 0.5 g, carboxymethyl cellulose sodium (CMC-Na) 20.0 g, Congo red 0.2 g, distilled water 1000 mL, 121°C sterilization for 20 min.

[0049] Strain cellulase activity detection: inoculate strain JY01 bacterial cake on cellulose Congo red medium, cultivate at 30°C for 5d, and find that hydrolysis circles appear on the outer edge of the colonies Figure 4), indicating that the strain can produce cellulase. Cellulase activity determined by cellulase kit: 25.3 U / mL.

[0050] Strain β-1, 3-glucanase activity detection: inoculate the strain JY01 bacterial cake on the β-1, 3-glucanase detection medium, and cultivate at 30°C for 5d. It is found that there are hydrolysis circles on the edge of the colony ( Figure 5 ), indicating that the strain can produce β-1, 3-glucanase. The β-1, 3-glucanase activity determined by β-1, 3-glucanase kit: 0.79 U / mL. Example 3

[0051] This example is Kitasatospora xanthocidica Study on the siderophore production ability of JY01 strain

[0052] Strain siderophore activity detection: inoculate the strain JY01 bacterial cake on the siderophore screening medium (CAS detection medium), and cultivate at 30°C for 7d. It is found that there are hydrolysis circles around the colony ( Figure 6 ), indicating that the strain can produce siderophore. The siderophore content determined by CAS detection solution is 188.95 μmol / L. Example 4

[0053] This example is Kitasatospora xanthocidica Study on the IAA ability of JY01 strain.

[0054] Strain IAA activity determination: inoculate the strain into TSB medium containing tryptophan (final concentration 3 mmol / L), cultivate at 170 rpm, 28°C for 7d, take 200 μL bacterial suspension into 2 mL centrifuge tube, at the same time, add equal volume of Salkowski colorimetric solution (weigh 1 g Fecl3.6H2O, add 21.485 mL concentrated H2SO4, and dilute to 50 mL), and take 100 μL uninfected TSB medium and equal volume of Salkowski colorimetric solution mixture as control, place in room temperature, avoid light, and observe after 30 min. Color change to red indicates IAA production, the deeper the red color, the stronger the IAA production ability, and no color change indicates no IAA production ( Figure 7 ). All experiments are repeated 3 times, and the IAA content determined by IAA activity determination kit (Shanghai enzyme-linked immunoassay kit) is 317.27 nmol / L. Example 5

[0055] This example is to prepare Kitasatospora xanthocidica Biocontrol agent of JY01 strain solid fermentation.

[0056] The preparation steps of the biocontrol agent are as follows.

[0057] (1) Preparation of JY01 seed culture: Spores from fresh slant of strain JY01 were inoculated into seed culture medium and cultured at 30℃ and 180 r / min for 2 days for later use; The seed culture medium formula is as follows: Seed culture medium: glucose 45.0 g, soybean powder 30.0 g, yeast powder 5.0 g, CaCO3 5.0 g, distilled water 1000 mL, pH 7.2-7.5, sterilized at 121℃ for 20 min.

[0058] (2) Preparation of JY01 solid fermentation biocontrol agent: The JY01 fermentation broth obtained in the above steps was inoculated into a solid fermentation medium for shallow-tray solid fermentation. The fermentation substrate thickness was 1.5-2 cm, the inoculation amount was 10%, the fermentation temperature was 28-30℃, and the fermentation was completed after 7-10 days. The substrate was covered with JY01 conidia, and the JY01 solid fermentation biocontrol agent was obtained, in which the spore amount reached 10 9 More than one per gram.

[0059] The solid culture medium formula is as follows: 25% wheat bran, 40% silkworm excrement, 20% corn starch, and 15% soybean flour, with a material-to-water ratio of 1:0.8, pH=7.2-7.5, and sterilization at 121 ℃ for 30 min. Example 6

[0060] This embodiment demonstrates the control effect of JY01 solid fermentation biocontrol agent on wheat stem base rot.

[0061] Select wheat seeds of uniform size with no damage to the outer skin, disinfect them with 3% sodium hypochlorite solution for 3 minutes, rinse them 5 times with sterile water, and incubate them at 25℃ for 2 days to promote germination.

[0062] Preparation of pathogenic bacteria: Pathogenic bacteria Fusarium pseudogracilis ( Fusarium pseudograminearum, (Abbreviated as Fp) was activated on PDA medium, and the spores were washed off with sterile water, filtered through sterile absorbent cotton, and the spore suspension was collected. The spore concentration in the filtrate was adjusted to 10-1 by microscopic counting. 6 Units / mL are available for use.

[0063] Two days after germination, wheat seeds were sown in pots (200g soil per pot), with 9 seeds per pot. Experimental design: The pot experiment included three treatments: a blank control (no inoculation with any microorganisms); a pathogen treatment of *Fusarium graminearum* (Fp): 20mL of pathogen spore solution was added to each pot (10... 6 (Cells / mL); JY01 solid inoculant treatment (Fp+JY01): Add 2% JY01 solid fermentation biocontrol agent to each pot, mix with soil, sow germinated wheat, and add pathogens (10) 7 days later when the wheat has one bud and one leaf. 6Wheat seedlings were transplanted in pots (diameter 20 cm, height 15 cm) with 5-6 seeds per pot, and 20 pots per treatment. The soil was mixed with 0.5% of vermiculite and 0.5% of perlite, and then sterilized at 121°C for 2 hours. After cooling, the soil was mixed with 0.5% of the solid biocontrol agent (Fp+JY01, 1 g / mL, 20 mL). All were placed in a greenhouse, 25°C, 12 h light / 12 h dark alternating conditions for culture. After 30 d of growth, the wheat seedlings were pulled out and the roots were washed clean with clean water, and the fresh weight of the wheat plants, plant height, stem diameter and other indicators were measured. The incidence of stem base rot of wheat seedlings was investigated, and the incidence and disease index were calculated, and the control effect was calculated according to the disease index. The test was repeated 3 times, and 6 pots were used for each treatment in each test.

[0064] The grading standard for the disease investigation of wheat seedling stem base rot is as follows: 0 level: the plant is not diseased; 1 level: the root or stem in the ground is brown, or the first leaf sheath has mild brown symptoms; 3 level: the first leaf sheath is obviously brown, but the leaf sheath is not black; 5 level: the first leaf sheath is obviously black or the second leaf sheath is obviously brown; 7 level: the third leaf sheath has brown symptoms, or the plant is stunted or close to death due to disease; 9 level: the plant is dead due to disease.

[0065] Disease index = [Σ (each disease classification x the number of diseased plants of that disease classification) / (the highest level in the classification standard x the total number of plants surveyed)] x 100.

[0066] Control effect (%) = [(disease index of the control group - disease index of the treatment group) / disease index of the control group] x 100%.

[0067] The pot experiment results obtained by the above method are shown in Table 3 and Figure 8 , 9 .

[0068]

[0069] As shown in Table 3, after treatment with Fp+JY01, the incidence rate decreased from 100% in the control to 77.8%, the disease index decreased from 50.10 in the control to 21.09, and the biocontrol efficiency was 57.90%. The plant height and fresh weight increased by 29.74% and 97.29%, respectively, indicating that the JY01 strain has excellent prevention and control effect on wheat stem base rot and has a growth-promoting effect.

[0070] As shown in Table 3, after treatment with Fp+JY01, the incidence rate decreased from 100% in the control to 77.8%, the disease index decreased from 50.10 in the control to 21.09, and the biocontrol efficiency was 57.90%. The plant height and fresh weight increased by 29.74% and 97.29%, respectively, indicating that the JY01 strain has excellent prevention and control effect on wheat stem base rot and has a growth-promoting effect. Figure 8 9 It can be seen that Fp is the experimental group inoculated with Pseudocercosporella herpotrichoides; Fp+JY01 is the experimental group inoculated with Pseudocercosporella herpotrichoides and the solid biocontrol agent of strain JY01; C is the blank control group without inoculation of any strain; it can be seen that compared with the wheat control group inoculated with Pseudocercosporella herpotrichoides, the wheat seeds treated with the solid biocontrol agent of strain JY01 showed no significant difference in growth after inoculation with Pseudocercosporella herpotrichoides, but the occurrence of wheat stem base rot was significantly reduced, indicating that the JY01 strain has a prevention and control effect on wheat stem base rot caused by Pseudocercosporella herpotrichoides. Example 7​

[0071] This embodiment demonstrates the control effect of JY01 solid fermentation biocontrol agent on corn stalk base rot.

[0072] Select corn seeds of uniform size with no damage to the outer skin, disinfect them with 3% sodium hypochlorite solution for 3 minutes, rinse them 5 times with sterile water, and germinate them at 25 ℃ with moisture for 3 days.

[0073] The pathogen of corn stalk rot is Fusarium oxysporum ( Fusarium oxysporum (Abbreviated as Fo) is activated on PDA slant and cultured at 28℃ for 5-7 days until conidia are abundant. Pathogen blocks are then extracted using a punch and inoculated into 100 mL of PDA liquid medium (into 250 mL Erlenmeyer flasks). The mixture is cultured at 28℃ and 170 rpm with shaking for 3-4 days. Microscopic examination is performed to observe the mycelium and spore morphology of the pathogen. After confirming no contamination, the conidia are harvested by filtration and the spore concentration is adjusted to 10. 6 Seeds / mL, ready for use. After 3 days of germination, corn seeds were sown in pots (500g soil per pot), one seed per pot. Experimental design: The pot experiment included three treatments: a blank control (no inoculation with any microorganisms); the pathogen-Fusarium oxysporum treatment (Fo): 20mL of pathogen spore solution was added to each pot (10... 6 (Cells / mL); JY01 solid inoculant treatment (Fo+JY01): Add 2% JY01 solid fermentation biocontrol agent to each pot, mix with soil, sow germinated corn, and add pathogens (10) 7 days later when the corn has one bud and one leaf. 6 (Number of seedlings / mL, 20mL). All seedlings were uniformly placed in a greenhouse and cultured under conditions of 25 ℃ and alternating 16h light / 8h dark. After 45 days of growth, the maize seedlings were pulled out, and the roots were rinsed clean with water. The above-ground and below-ground fresh weight, plant height, and stem diameter of the maize plants under different treatments were measured. The incidence of stem rot in maize seedlings was investigated, and the incidence rate and disease index were calculated. The control effect was calculated based on the disease index. The experiment was repeated three times, with six pots of each treatment per experiment.

[0074] The grading standards for corn seedling stem rot disease are as follows: Grade 0: No disease on the plant; Grade 1: Slight yellowing of the bottom leaves and wilting of the leaf tips; plant growth is basically normal, with small yellow-brown spots visible on the roots; Grade 3: Yellowing of multiple leaves from bottom to top, with some leaves drying out; significant stunting and slow growth; Grade 5: Yellowing of all leaves, with more than half drying out; severely stunted plant with slight browning at the stem base; Grade 7: Drying out of all leaves, with only the central leaves remaining green; plant growth stagnation and necrosis spreading at the stem base; Grade 9: Complete death of the plant; some plants show tillering or deformities; large areas of brown rot on the roots and stem base.

[0075] Disease index = [Σ(each disease grade × number of affected plants at that disease grade) / (number of highest grade in the grading standard × total number of plants surveyed)] × 100.

[0076] Prevention and control effect (%) = [(disease index of control group - disease index of treatment group) / disease index of control group] ×100%.

[0077] The results of the pot experiment obtained using the above method are shown in Table 4 and Figure 10 As shown.

[0078]

[0079] Maize seeds were treated with JY01 solid biocontrol agent, and the biocontrol potential of the JY01 strain against maize stalk rot was determined through an indoor pot experiment. As shown in Table 4, the disease incidence rate of plants treated with Fo+JY01 decreased from 66.67% in the control to 33.33%, and the disease index decreased from 17.28 in the control to 9.26, with a biocontrol efficiency of 46.41%. Plant height and fresh weight increased by 40.30% and 69.09%, respectively, indicating that the JY01 strain has a control effect on maize stalk rot and also has excellent growth-promoting effects.

[0080] Depend on Figure 10 As can be seen, Fo represents the experimental group inoculated only with Fusarium oxysporum; Fo+JY01 represents the experimental group inoculated with both Fusarium oxysporum and the solid biocontrol agent of strain JY01; C represents the blank control group without inoculation with any strain. It can be seen that compared with the maize control group inoculated with Fusarium oxysporum, although the maize stalk base rot was not severe after inoculation with Fusarium oxysporum, the maize growth was significantly different, with plant height and fresh weight increasing by 40.30% and 69.09% respectively, indicating that strain JY01 has a growth-promoting effect on maize.

[0081] The above tests prove that the candidates selected by the applicant... Kitasatospora xanthocidica The JY01 strain possesses both biocontrol and growth-promoting functions, and can be used in the preparation of microbial fertilizers. Furthermore, its microbial agent preparation process integrates the recycling of agricultural waste such as silkworm excrement, providing an environmentally friendly solution for soil-borne fungal diseases (such as root rot) in crops like corn and soybeans. This has significant application value in reducing chemical pesticide pollution and promoting green agriculture.

[0082] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A plant Xanthocidica strain JY01, characterized in that, Its classification is named Xanthocidica It is deposited at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, on June 3, 2025, with accession number CGMCC NO.34740.

2. Containing the as described in claim 1 Xanthocidica JY01 bacterial agent.

3. As described in claim 1 Xanthocidica The application of strain JY01 or the microbial agent of claim 2 in the preparation of biocontrol agents for controlling soil-borne fungal diseases; the pathogen of the soil-borne fungal disease is Fusarium oxysporum (…). Fusarium oxysporum ) and / or Fusarium pseudocaryophyllum ( Fusarium pseudograminearum ).

4. As described in claim 1 Xanthocidica The application of strain JY01 or the agent of claim 2 in the preparation of biocontrol agents for controlling soil-borne fungal diseases; wherein the soil-borne fungal diseases are wheat stem base rot, pepper anthracnose, soybean root rot, cucumber wilt and / or corn stem base rot.

5. As described in claim 1 Xanthocidica Application of strain JY01 or the microbial agent of claim 2 in promoting the growth of corn or wheat.

6. As described in claim 1 Xanthocidica The application of strain JY01 or the bacterial agent of claim 2 in the production of siderophores, cellulase and / or β-1,3-glucanase.

7. Application as described in claim 1 Xanthocidica A method for controlling wheat stem rot using strain JY01 or the inoculant of claim 2, characterized in that... The method is as follows: [The text abruptly ends here, likely due to an incomplete sentence or a missing section.] Xanthocidica The JY01 spore-infused inoculant is applied to seeds at a ratio of 2% or used as a soil dressing; the spore count of the inoculant reaches 10. 9 More than one per gram.

8. Application as described in claim 1 Xanthocidica The method for controlling maize stalk rot using strain JY01 or the inoculant of claim 2 is characterized in that... The method is as follows: [The text abruptly ends here, likely due to an incomplete sentence or a missing section.] Xanthocidica The JY01 spore-infused inoculant is applied to seeds at a ratio of 2% or used as a soil dressing; the spore count of the inoculant reaches 10. 9 More than one per gram.

9. As described in claim 1 Xanthocidica Application of strain JY01 or the microbial agent as described in claim 2 in the preparation of bio-fertilizers for wheat and / or corn.

Images