Kitasatospora xanthophycea JY01 strain and application thereof

Abstract

The invention provides a Kitasatospora xanthophycea JY01 strain and application thereof, the strain is separated from intestinal tracts of spring silkworms, has good disease-resistant and growth-promoting effects, and is specifically expressed in that cellulase, beta-1, 3-glucanase, siderophore and auxin IAA can be secreted; pot experiments show that the biocontrol efficiency of the microbial inoculum to wheat stalk rot is 57.90%, the biocontrol efficiency of the microbial inoculum to corn stalk rot is 46.41%, and the plant height and fresh weight are both significantly increased. The microbial agent is expected to be applied to preparation of biological bacterial fertilizer for effectively preventing and controlling soil-borne fungal diseases.

Description

Technical Field

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

[0002] Soil-borne fungal diseases are a major threat to global agricultural production. Their soil-borne nature leads to frequent cropping problems. Fusarium Pathogens such as  ...

[0003] Actinomycetes are an important group of soil microorganisms and play an important role in preventing and controlling soil-borne diseases. Their mechanism of action is mainly to inhibit the growth of pathogens by secreting antagonistic substances, regulate soil microbial flora, and improve the structure of microbial communities.

[0004] While biological control technology is considered a green approach to disease prevention and control, existing antagonistic agents face significant technical bottlenecks. Currently commercialized Trichoderma agents have limited inhibition rates against Fusarium and primarily target single pathogens, making them inadequate for complex infections. Furthermore, most antagonistic strains lack growth-promoting properties. Summary of the Invention

[0005] In view of the above, it is particularly necessary to screen out actinomycetes with a high inhibition rate against soil-borne pathogenic fungi, and develop the bacteria into biological agents that can not only effectively prevent and control soil-borne diseases caused by Fusarium but also promote the growth of corn or wheat. In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0006] The present invention screened out a Kitasatospora xanthocidica JY01 strain, which is classified as Kitasatospora xanthocidica , its deposit number is CGMCC NO.34740. The strain is deposited in the General Microbiology Center of China Culture Collection Administration, address: No. 3, Yard 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 according to claim 1 Kitasatospora xanthocidica JY01 bacterial agent.

[0008] The present invention also provides Kitasatospora xanthocidica Use of the JY01 strain or the above-mentioned bacterial agent in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases.

[0009] The present invention further illustrates that the pathogen of the soil-borne fungal disease is Fusarium oxysporum ( Fusarium oxysporum ), Pseudomonas graminearum ( Fusarium pseudograminearum ) and / or Colletotrichum spp. ( Colletotrichum capsicum ).

[0010] The present invention further illustrates that the soil-borne fungal disease is wheat stem rot, pepper anthracnose, soybean root rot, cucumber wilt and / or corn stem rot.

[0011] The present invention also provides Kitasatospora xanthocidica Application of the JY01 strain or the above-mentioned bacterial agent in promoting the growth of corn or wheat.

[0012] The present invention also provides Kitasatospora xanthocidica Use of the JY01 strain or the above-mentioned bacterial agent in producing siderophore, cellulase and / or β-1,3-glucanase.

[0013] The present invention also provides the application as described Kitasatospora xanthocidica The method for preventing and controlling wheat stem base rot by using the JY01 strain or the above-mentioned bacterial agent is as follows: Kitasatospora xanthocidica JY01 spore fungicide can be mixed with seeds or applied to the soil at a ratio of 2%.

[0014] The present invention also provides the application as described Kitasatospora xanthocidica The method for preventing and controlling corn stalk rot by using the JY01 strain or the above-mentioned bacterial agent is as follows: Kitasatospora xanthocidica JY01 spore fungicide can be mixed with seeds or applied to the soil at a ratio of 2%.

[0015] The present invention also provides Kitasatospora xanthocidica Application of the JY01 strain or the bacterial agent described above in the preparation of biological fertilizer.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0017] The present invention screened Kitasatospora xanthocidicaThe JY01 strain exhibits broad-spectrum antagonistic activity against soil-borne fungal diseases including wheat stem rot, pepper anthracnose, soybean root rot, cucumber wilt, and / or corn stem rot, surpassing the limitations of existing biocontrol strains in their single-pathogen control. Research has also shown that the JY01 strain produces cellulase, β-1,3-glucanase, and siderophores, as well as the growth-promoting hormone IAA, which promotes the growth of corn and wheat. This demonstrates that the JY01 strain possesses dual functions of disease prevention and growth promotion. Potted plant experiments have demonstrated significant protection against wheat stem rot and / or corn stem rot, and have a positive growth-promoting effect on plants, particularly wheat and corn. This application also converts agricultural waste into raw materials for the production of microbial agents, using wheat bran (25%), silkworm feces (40%), corn starch (20%) and soybean powder (15%) as fermentation matrices, with a material-water ratio of 1:0.8, and obtaining spores of ≥10 after shallow tray fermentation (28–30°C, 7–10 days). 9 The stabilizing bacteria agent with a concentration of 1000 / g has opened up a new green and environmentally friendly path to solve the environmental pollution caused by waste such as silkworm feces. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The inhibitory effect of the strain JY01 of this application on pathogenic fungi; A: wheat stem rot pathogen; B: pepper anthracnose pathogen; C: soybean root rot pathogen; D: cucumber wilt pathogen.

[0019] Figure 2 These are colony morphology diagrams of the strain JY01 of the present application; wherein A: spore morphology of strain JY01 under an optical microscope; B: spore morphology of strain JY01 under a scanning electron microscope; C: colony plate morphology of strain JY01.

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

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

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

[0023] Figure 6 This is a diagram of the hydrolysis circle formed by the strain JY01 of this application on the CAS detection medium (iron carrier detection medium).

[0024] Figure 7The following are the qualitative experimental results of IAA production by the strain JY01 of the present application (reaction solution color change diagram); CK is the color of uninoculated TSB culture solution after reaction with an equal volume of Salkowski colorimetric solution, and JY01 is the color of the supernatant of strain JY01 after TSB culture after reaction with an equal volume of Salkowski colorimetric solution.

[0025] Figure 8 This is a diagram showing the control effect of the strain JY01 of this application on wheat stem base rot; among them, CK is the blank control treatment; Fp is the pathogen-Farberella graminearum treatment; Fp+JY01 is the Farberella graminearum + JY01 solid bacterial agent treatment.

[0026] Figure 9 This is an enlarged effect diagram of the effect of the strain JY01 of this application on the prevention and control of wheat stem base rot on wheat rhizomes; among them, (a) wheat rhizomes after inoculation with F. graminearum, (b) wheat rhizomes inoculated with F. graminearum after seeds were treated with the solid biocontrol agent of strain JY01.

[0027] Figure 10 This is a diagram showing the control effect of the strain JY01 of this application on corn stalk rot; among them, CK is the blank control treatment; Fo is the treatment with the pathogen - Fusarium oxysporum; Fo+JY01 is the treatment with Fusarium oxysporum + JY01 solid bacterial agent. DETAILED DESCRIPTION

[0028] All features disclosed in this specification, or all steps in the disclosed methods or processes, except mutually exclusive features and / or steps, can be combined in any manner.

[0029] Any feature disclosed in this specification (including any accompanying claims and abstract), unless otherwise stated, is merely an example of a series of equivalent or similar features.

[0030] The culture media, reagents and instruments involved in this experiment can be purchased on the market. Example 1

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

[0032] 1. Screening of strains and determination of antagonistic spectrum: 50 4th instar larvae of spring silkworms were collected from Huangshan, Anhui, Rugao, Jiangsu, and Lishui, Zhejiang. They were starved overnight and wiped with sterile water and 75% ethanol. The body surface was disinfected by soaking in 75% ethanol for 3 minutes. The larvae were rinsed with sterile water 3-5 times. The intestine of the silkworm larvae was obtained by dissection on a clean bench. A small amount of sterile water was added to a sterile mortar and the homogenate was ground. 100 μL of the homogenate was drawn into 900 μL of sterile water and serially diluted to 10 -5, select 10 -3 , 10 -4 , 10 -5 Three dilutions were spread on Gao's medium No. 1 plates and cultured upside down at 30°C for 5-7 days. Single actinomycete colonies were picked and streaked on Gao's medium No. 1 plates for purification. The obtained single colonies were transferred to slant cultures and stored at 4°C.

[0033] Among them, Gao's medium No. 1 includes the following ingredients: soluble starch 20g, KNO3 1.0g, K2HP04·7H2O0.5g, MgSO4·7H2O 0.5g, NaCl 0.5g, FeSO4·7H2O 0.01g, agar 20g, deionized water 1000mL, pH 7.2.

[0034] Antagonistic strains were screened by plate confrontation method. Take a fresh slant of cultured actinomycetes, add a small amount of sterile water, prepare a spore suspension, take 100 μL of the spore suspension and spread it on Gao's No. 1 plate. Incubate at 30℃ for 5-7 days. When the spores are full, use a 5mm punch to punch out the actinomycete cake and isolate the cucumber wilt pathogen ( Fusarium oxysporum f. sp. cucumerinum), soybean root rot pathogen ( Fusarium oxysporum f. sp . soybean), pepper anthracnose pathogen ( Colletotrichum capsica f. sp. chili), wheat stem rot pathogen ( Fusarium pseudograminearum f. sp. wheat), rice bakanae disease pathogen (Fusarium fujikuroi ), corn stalk rot pathogen ( Fusarium oxysporum f. sp . Corn) cakes were placed in the center of a PDA plate. Two actinomycete cakes were placed symmetrically on either side, 2 cm from each cake. Cultures were performed at 30°C for 5-7 days. Three replicates were used for each group. The inhibition rate was calculated to screen for actinomycete strains with strong antagonistic activity. The inhibition results from the antagonism experiments are shown in Table 1.

[0035] Inhibition rate (%) = (pathogen colony diameter in the control group − pathogen colony diameter in the treatment group) / (pathogen colony diameter in the control group) × 100%.

[0036] A total of 20 actinomycete strains were obtained from the silkworm intestine through screening, and 5 actinomycete strains showed antagonistic activity. Among them, strain JY01 (from the spring silkworm breeding area of ​​Lishui City, Zhejiang Province) grew rapidly, had abundant conidia, had a broad antibacterial spectrum and strong antagonistic effect. It had a significant effect on plate confrontation culture with wheat stem rot pathogen (see Figure 1 ).

[0037]

[0038] As shown in Table 1, strain JY01 achieved an inhibition rate of 59.29% against the pathogen of wheat stem rot, and inhibition rates of over 60% against the pathogens of pepper anthracnose, soybean root rot, cucumber wilt, and corn stem rot. However, strain JY01 showed no significant antagonistic effect against the pathogen of rice bakanae disease. Strain JY01 also showed no significant antagonistic effect against plant pathogens such as bacterial wilt, which causes diseases in Solanaceae crops like tomatoes, peppers, and eggplants.

[0039] 2. Identification of antagonistic actinomycete JY01.

[0040] (1) Observation of morphological characteristics of antagonistic actinomycetes JY01: On Gao's medium No. 1, the colony of JY01 is off-white, and the aerial hyphae are off-white ( Figure 2 Strain JY01 was streaked onto Gao's medium No. 1. A sterilized coverslip was inserted obliquely into the plate, maintaining a 45-degree angle between the coverslip and the medium. The culture was incubated at 30°C for 5 days. The coverslip was removed with tweezers and slides were prepared for observation using a scanning electron microscope. Spores of the antagonistic strain JY01 were straight, with a rough spore surface and cylindrical conidia.

[0041] (2) The physiological and biochemical characteristics of the antagonistic actinomycete JY01 are shown in Table 2: The results of the physicochemical properties of the strain JY01 grown on gelatin liquefaction, milk peptization, starch hydrolysis, cellulose decomposition, Chessner agar and carbon and nitrogen source utilization media for 4-30 days showed that the strain JY01 could hydrolyze starch, liquefy gelatin, produce hydrogen sulfide, decompose cellulose, 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 biological identification of antagonistic actinomycetes JY01: The strain JY01 was sent to Shanghai Lingen Biotechnology Co., Ltd. for 16S rRNA sequencing. The sequencing results were subjected to BLAST comparison analysis of related sequences using the EzBioCloud platform. After sequencing, the JY01 gene sequence totaling 1397 bp was obtained. The sequence was logged into NCBI (accession number PQ459648) for sequence alignment, and the top 9 effective strain sequences with high homology to JY01 were selected. The phylogenetic tree was constructed using the neighbor-joining method (NJ) using MEGA 11.0 software. The results showed that the strain JY01 had a strong affinity with the flavomycin-resistant North Sporium ( Kitasatospora xanthocidica ) has a homology of 99.71%. Figure 3 ), and combined with the strain morphology, physiological and biochemical indicators, the actinomycete JY01 was preliminarily identified as Kitasatospora xanthocidica .

[0044] The applicant has already Kitasatospora xanthocidica The JY01 strain is deposited in the General Microbiology Center of the China Culture Collection Administration, with the deposit number CGMCC NO.34740. The deposit address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the deposit date is June 3, 2025. Example 2

[0045] This embodiment is Kitasatospora xanthocidica Study on the cellulase and β-1,3-glucanase production ability of JY01 strain.

[0046] Carbohydrate-active enzyme (CAZyme) activity measurements, including cellulase and β-1,3-glucanase, were performed. Spores of strain JY01 were inoculated into 100 mL of liquid TSB medium and cultured at 28°C with shaking at 180 rpm for 7 days. The culture was then centrifuged at 8000 rpm for 10 minutes, and the supernatant was used for quantitative enzyme activity determination. Cellulase and β-1,3-glucanase activities were measured using a cellulase activity assay kit (Suzhou Keming Biotechnology Co., Ltd.) and a β-1,3-glucanase assay kit (Suzhou Keming Biotechnology Co., Ltd.), respectively. One unit of cellulase activity (U) is defined as the production of 1 μg of glucose per minute per mL of sample solution at 37°C. One unit of β-1,3-glucanase activity (U) is defined as the production of 1 mg of reducing sugar per hour per mL of sample solution at 37°C. All experiments were repeated in triplicate.

[0047] Among them, the β-1,3-glucanase detection medium includes the following components: dextran 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, sterilized at 121℃ for 20 min.

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

[0049] Detection of cellulase activity of strains: strain JY01 cake was inoculated on cellulose Congo red medium and cultured at 30℃ for 5 days. Hydrolysis zone was found on the outer edge of the colony ( Figure 4), indicating that the strain can produce cellulase. The cellulase activity measured by the cellulase kit was 25.3 U / mL.

[0050] β-1,3-glucanase activity test of the strain: Inoculate the strain JY01 cake on the β-1,3-glucanase test medium and culture at 30℃ for 5 days. A hydrolysis zone was found on the outer edge of the colony ( Figure 5 ), indicating that the strain can produce β-1,3-glucanase. The β-1,3-glucanase activity measured by the β-1,3-glucanase kit was 0.79 U / mL. Example 3

[0051] This embodiment is Kitasatospora xanthocidica Study on the Siderophore Production Ability of JY01 Strain Detection of the activity of the strain producing siderophore: The bacterial cake of strain JY01 was inoculated on the siderophore screening medium (CAS detection medium) and cultured at 30℃ for 7 days. Hydrolysis zones were found around the colonies ( Figure 6 ), the strain can produce siderophores. The siderophore content measured using CAS assay solution was 188.95 μmol / L. Example 4

[0052] This embodiment is Kitasatospora xanthocidica Study on the IAA capacity of JY01 strain.

[0053] Determination of IAA production activity of the strain: The strain was inoculated into TSB medium containing tryptophan (final concentration of 3 mmol / L) and cultured at 170 rpm and 28°C for 7 days. 200 μL of the bacterial suspension was transferred to a 2 mL centrifuge tube and an equal volume of Salkowski colorimetric solution (weigh 1 g FeCl3.6H2O and add 21.485 mL concentrated H2SO4 to 50 mL). A mixture of 100 μL of uninoculated TSB medium and an equal volume of Salkowski colorimetric solution was used as a control. The strain was placed in the dark at room temperature for 30 minutes and then observed. The strain that turned red produced IAA. The darker the red, the stronger the IAA production ability. The strain that did not change color did not produce IAA. Figure 7 All experiments were repeated three times, and the IAA activity assay kit (Shanghai enzyme-linked immunosorbent assay kit) was used to detect the IAA content, which was 317.27 nmol / L. Example 5

[0054] This example is to prepare Kitasatospora xanthocidica JY01 strain solid fermentation biocontrol agent.

[0055] The steps for preparing the biocidal agent are as follows.

[0056] (1) Preparation of JY01 seed liquid: Inoculate spores from a fresh slant of strain JY01 into a seed liquid culture medium, culture at 30°C and 180 r / min for 2 days, and set aside. The seed liquid culture medium formula is as follows: seed culture medium: 45.0 g glucose, 30.0 g soybean powder, 5.0 g yeast powder, 5.0 g CaCO3, 1000 mL distilled water, pH 7.2-7.5, 121°C, sterilize for 20 min.

[0057] (2) Preparation of JY01 solid fermentation biocontrol agent: The JY01 fermentation liquid obtained in the above steps was inoculated into a solid fermentation medium for shallow tray solid fermentation. The thickness of the fermentation matrix was 1.5-2 cm, the inoculation amount was 10%, the fermentation temperature was 28-30 ° C, and the fermentation was completed after 7-10 days. The matrix was covered with JY01 conidia, and the JY01 solid fermentation biocontrol agent was obtained, in which the spore amount reached 10 9 More than 1g.

[0058] Among them, the solid culture medium formula is: 25% wheat bran, 40% silkworm feces, 20% corn starch, 15% soybean powder, the material-water ratio is 1:0.8, pH=7.2-7.5, and sterilization is carried out at 121℃ for 30 minutes. Example 6

[0059] This example shows the control effect of JY01 solid fermentation biocontrol agent on wheat stem rot.

[0060] Wheat seeds of uniform size and without damaged skin were selected, disinfected with 3% sodium hypochlorite solution for 3 minutes, rinsed with sterile water 5 times, and cultured at 25℃ for 2 days to accelerate the germination of wheat.

[0061] Preparation of pathogens: Pathogenic bacteria Fusarium graminearum ( Fusarium pseudograminearum, The spores (abbreviated as Fp) were activated on PDA medium, the spores were washed with sterile water, and the spore suspension was collected by filtering with sterile absorbent cotton. The spore concentration in the filtrate was adjusted to 10 6 / mL for future use.

[0062] Wheat seeds were sown in pots (200 g soil per pot) after germination for 2 days, with 9 seeds planted per pot. Experimental design: The pot experiment was set up with 3 treatments: blank control (no microorganisms were inoculated); pathogen-Farsilia pseudograminearum treatment (Fp): 20 mL of pathogen spore solution (10 6 / mL); JY01 solid microbial agent treatment (Fp+JY01): 2% JY01 solid fermentation biocontrol agent was added to each pot, mixed with soil, and wheat was sown after germination. After 7 days, pathogens were added when the wheat had one bud and one leaf (10 6The wheat seedlings were uniformly cultured in a greenhouse at 25°C under 12-hour light / 12-hour dark conditions. After 30 days of growth, the wheat seedlings were pulled out and their roots rinsed with clean water. Plant fresh weight, plant height, and stem diameter were measured for each treatment. The incidence of wheat stem rot at the seedling stage was investigated, and the incidence and disease index were calculated. The control efficacy was then calculated based on the disease index. The experiment was replicated three times, with six pots planted per treatment in each trial.

[0063] The grading standard for wheat seedling stem rot disease survey is as follows: Level 0: The plant is not diseased; Level 1: The root or underground stem turns brown, or the first leaf sheath shows slight browning symptoms; Level 3: The first leaf sheath turns obviously brown, but the leaf sheath does not turn black; Level 5: The first leaf sheath turns obviously black or the second leaf sheath turns obviously brown; Level 7: The third leaf sheath shows browning symptoms, or the plant is retarded or close to death due to the disease; Level 9: The plant dies due to the disease.

[0064] Disease index = [Σ (each disease grade × number of diseased plants at that disease grade) / (highest grade in the grading standard × total number of plants surveyed)] × 100.

[0065] Prevention and treatment effect (%) = [(disease index of control group - disease index of treatment group) / disease index of control group] × 100%.

[0066] The potted plant test results obtained by the above method are shown in Table 3 and Figure 8 、 9 shown.

[0067]

[0068] As shown in Table 3, after treatment with Fp+JY01, the incidence rate dropped from 100% in the control to 77.8%, and the disease index decreased from 50.10 in the control to 21.09, resulting in a biocontrol efficiency of 57.90%. Plant height and fresh weight increased by 29.74% and 97.29%, respectively, demonstrating that the JY01 strain has excellent control effects on wheat stem rot and has a growth-promoting effect.

[0069] Depend on Figure 8 、 9 It can be seen that Fp is the experimental group inoculated with only F. graminearum; Fp+JY01 is the experimental group inoculated with F. graminearum and the solid biocontrol agent of strain JY01; C is the blank control group not inoculated with any strain; it can be seen that compared with the wheat control group inoculated with F. graminearum, there is no significant difference in the growth of wheat after the wheat seeds treated with JY01 solid biocontrol agent are inoculated with F. graminearum, but the occurrence of wheat stem rot is significantly reduced, indicating that the JY01 strain has a preventive and control effect on wheat stem rot caused by F. graminearum. Example 7

[0070] This example shows the control effect of JY01 solid fermentation biocontrol agent on corn stalk rot.

[0071] Select corn seeds of uniform size and without damaged skin, disinfect them with 3% sodium hypochlorite solution for 3 minutes, rinse them with sterile water 5 times, and culture them at 25℃ with moisturizing for 3 days to accelerate the germination of corn.

[0072] Corn stalk rot pathogen - Fusarium oxysporum ( Fusarium oxysporum , abbreviated as Fo) was activated on a PDA slant and cultured at 28°C for 5-7 days. When the conidia were plump, the pathogenic bacteria were punched out with a hole punch and inoculated into 100 mL PDA liquid culture medium (packed in a 250 mL Erlenmeyer flask). The culture was shaken at 28°C and 170 rpm for 3-4 days. The hyphae and spore morphology of the pathogen were observed under a microscope. After confirming that there was no contamination, the conidia were filtered and harvested, and the spore concentration was adjusted to 10 6 3 days after germination, corn was sown in pots (500g soil per pot), with one seed per pot. Experimental design: The pot experiment was set up with three treatments: blank control (no microorganisms were inoculated); pathogen-Fusarium oxysporum treatment (Fo): 20mL of pathogen spore solution was added to each pot (10 6 / mL); JY01 solid microbial agent treatment (Fo+JY01): 2% JY01 solid fermentation biocontrol agent was added to each pot, mixed with soil, and the germinated corn was sown. After 7 days, pathogens (10 6 The corn seedlings were uniformly cultured in a greenhouse at 25°C under 16h light / 8h dark conditions. After 45 days of growth, the corn seedlings were pulled out and their roots rinsed with clean water. The fresh weight of the aboveground and lower parts of the corn plants, plant height, and stem diameter were measured for each treatment. The incidence of corn stalk rot at the seedling stage was investigated, and the incidence and disease index were calculated. The control efficacy was then calculated based on the disease index. The experiment was replicated three times, with six pots planted per treatment in each trial.

[0073] The grading standards for the investigation of corn base rot in the seedling stage are as follows: Level 0, the plant is not diseased; Level 1, the bottom leaves are slightly yellow and the leaf tips are wilted; the plant growth is basically normal, and small yellow-brown spots can be seen on the roots; Level 3, multiple leaves are yellowed from bottom to top, and some leaves are withered; the plant is obviously dwarfed and growth is slow; Level 5, all leaves of the plant are yellowed, and more than half of them are withered; the plant is severely stunted, and the base of the stem is slightly browned; Level 7, all leaves of the plant are withered, and only the heart leaves remain green; the plant growth stagnates, and necrosis expands at the base of the stem; Level 9, the plant is completely dead; some tillers or deformities appear; and large areas of brown rot on the roots and stem base.

[0074] Disease index = [Σ (each disease level × number of diseased plants at that level) / (highest level in the grading standard × total number of plants surveyed)] × 100.

[0075] Prevention and treatment effect (%) = [(disease index of control group - disease index of treatment group) / disease index of control group] × 100%.

[0076] The potted plant test results obtained by the above method are shown in Table 4 and Figure 10 shown.

[0077]

[0078] Corn seeds were treated with JY01 solid biocontrol agent, and the biocontrol potential of JY01 against corn stalk rot was determined in an indoor pot experiment. As shown in Table 4, the incidence 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, resulting in a biocontrol efficiency of 46.41%. Plant height and fresh weight increased by 40.30% and 69.09%, respectively, demonstrating that JY01 is effective in controlling corn stalk rot and has excellent growth-promoting effects.

[0079] Depend on Figure 10 It can be seen that Fo is the experimental group inoculated with Fusarium oxysporum only; Fo+JY01 is the experimental group inoculated with Fusarium oxysporum and the solid biocontrol agent of strain JY01; C is the blank control group not inoculated with any strain; it can be seen that compared with the corn control group inoculated with Fusarium oxysporum, the corn seeds treated with JY01 solid biocontrol agent did not suffer from severe stalk rot after inoculation with Fusarium oxysporum, but there was a significant difference in the growth of corn, with plant height and fresh weight increasing by 40.30% and 69.09% respectively, indicating that the JY01 strain has a growth-promoting effect on corn.

[0080] The above test proves that the applicant has screened Kitasatospora xanthocidica The JY01 strain possesses both biocontrol and growth-promoting properties and can be used in the production of microbial fertilizers. Furthermore, its microbial preparation process incorporates the recycling of agricultural waste, such as silkworm manure, 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.

[0081] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. One plant Xanthocidica The JY01 strain is characterized by: Its classification is named Xanthocidica It is deposited in the General Microbiology Center of China Culture Collection Administration, with the deposit address at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The deposit date is June 3, 2025, and its deposit number is CGMCC NO.34740.

2. Containing the Xanthocidica JY01 bacterial agent.

3. As claimed in claim 1 Xanthocidica Use of the JY01 strain or the bacterial agent according to claim 2 in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases; the pathogen of the soil-borne fungal disease is Fusarium oxysporum ( Fusarium oxysporum ) and / or F. graminearum ( Fusarium pseudograminearum ).

4. as claimed in claim 1 Xanthocidica Use of the JY01 strain or the microbial agent according to claim 2 in the preparation of a biocontrol agent for preventing and controlling soil-borne fungal diseases; the soil-borne fungal diseases are wheat stem rot, pepper anthracnose, soybean root rot, cucumber wilt and / or corn stem rot.

5. As claimed in claim 1 Xanthocidica Use of the JY01 strain or the bacterial agent according to claim 2 in promoting the growth of corn or wheat.

6. As claimed in claim 1 Xanthocidica Use of the JY01 strain or the bacterial agent according to claim 2 in producing siderophores, cellulase and / or β-1,3-glucanase.

7. Application as claimed in claim 1 Xanthocidica The method for preventing and controlling wheat stem rot by using the JY01 strain or the bacterial agent according to claim 2 is characterized in that: The method is: Xanthocidica The JY01 spore agent is mixed with seeds or applied to the soil at a ratio of 2%; the spore amount of the agent reaches 10 9 More than 1g.

8. Application as claimed in claim 1 Xanthocidica The method for preventing and controlling corn stalk rot by using the JY01 strain or the bacterial agent according to claim 2 is characterized in that: The method is: Xanthocidica The JY01 spore agent is mixed with seeds or applied to the soil at a ratio of 2%; the spore amount of the agent reaches 10 9 More than 1g.

9. As claimed in claim 1 Xanthocidica Use of the JY01 strain or the bacterial agent as claimed in claim 2 in the preparation of biological fertilizer for wheat and / or corn.

Images