Composite functional bacterial agent for preventing and controlling wheat scab and vomitoxin and application of composite functional bacterial agent

Abstract

The invention discloses a composite functional bacterial agent for preventing and controlling wheat scab and vomitoxin and application of the composite functional bacterial agent. The composite functional bacterial agent is applied to wheat scab and deoxynivalenol pollution caused by fusarium graminearum. The composite functional bacterial agent comprises a biocontrol strain bacillus subtilis DC-1 (Bacillus subtilis DC-1) and a degradation strain nocardia sp. MOZ-1 (Nocardia sp. MOZ-1), and the composite functional bacterial agent is prepared from the biocontrol strain bacillus subtilis DC-1, the degradation strain nocardia sp. MOZ-1 and the degradation strain nocardia sp. MOZ-1. The complex microbial inoculant can significantly inhibit infection of fusarium graminearum and reduce accumulation of DON in wheat, is low in production cost, reduces use of chemical pesticides and pollution of biotoxins in agricultural products, and can be effectively applied to the field of agricultural biological control.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural biological control, and in particular to a composite functional bacterial agent for preventing and controlling wheat fusarium rust and vomitoxin and an application thereof. Background Art

[0002] Affected by global climate change, farming methods, fertilizer application, pathogen resistance and other factors, the area of ​​wheat fusarium head blight has gradually expanded and the frequency of occurrence has continued to increase, becoming the biggest hidden danger to wheat production safety. Wheat plants in the growing period will change color and wilt after being infected, and in severe cases, they will die. Mature grains infected by pathogens will shrink and their quality will be seriously reduced. At the same time, studies have found that deoxynivalenol (DON) produced by pathogens has teratogenic and carcinogenic effects, which not only causes a large-scale reduction in wheat grain production, but also affects the quality and safety of agricultural products.

[0003] DON can inhibit the synthesis of proteins, DNA and RNA, has a wide range of toxic effects on organisms, and has no specific target organs. Exposure in vivo exceeding a certain concentration can cause toxic effects on animals and humans. Studies have shown that DON is teratogenic and carcinogenic, and has irreversible effects on the nervous and immune systems of humans and animals. Excessive intake can cause chronic and acute poisoning, and even lead to death. Even when exposed to non-toxic concentrations, DON can cause potential harmful effects on organism tissues.

[0004] At present, there are many studies on wheat fusarium head blight biocontrol bacteria. CN104904751B discloses a liquid wheat fusarium head blight biocontrol agent and its preparation method. The effective active ingredients of the biocontrol agent are composed of Bacillus subtilis and its fermentation metabolites, biochemical fulvic acid and chitosan oligosaccharide. Each effective component synergistically prevents and treats wheat fusarium head blight through different action modes, with better prevention effect, and is environmentally friendly, residue-free, pollution-free and does not produce drug resistance. CN115851495B discloses a biocontrol bacteria for preventing and treating wheat fusarium head blight and its application. The biocontrol strain is classified and named as Burkholderia gladiolus ( Burkholderiagladioli ), the strain can colonize in wheat, has a broad-spectrum antibacterial activity, and when mixed with spores of Fusarium graminearum PH-1, it can not only 100% inhibit the occurrence of fusarium head blight, but also significantly reduce the accumulation of DON toxins. There are also many studies on DON-degrading bacteria. CN111560327A discloses a strain of Alcaligenes faecalis that antagonizes Fusarium graminearum and efficiently degrades DON, and its application. The Alcaligenes faecalis NF037 strain has the effect of inhibiting Fusarium graminearum and has a strong ability to degrade DON in wheat grains.

[0005] Given that wheat fusarium rust and DON contamination caused by Fusarium graminearum can reduce wheat yield and quality, existing technologies only focus on biological control of wheat fusarium rust or biological detoxification of DON. It is crucial to explore composite functional bacterial agents that can both prevent and control wheat fusarium rust and degrade DON for high quality and high yield of wheat. Summary of the invention

[0006] The purpose of the present invention is to overcome the lack of a composite functional bacterial agent that can both prevent and control wheat fusarium and degrade DON in the prior art. After testing the effect of the composite functional bacterial agent on wheat quality and yield, the present invention provides a composite functional bacterial agent for preventing and controlling wheat fusarium and vomitoxin and its application.

[0007] To achieve the above object, the present invention provides the following technical solutions: The present invention provides a wheat fusarium rust biocontrol bacterium, which is classified and named as Bacillus subtilis DC-1, and was deposited in the China Center for Type Culture Collection on November 7, 2024, with a deposit number of CCTCC NO: M 20242397.

[0008] The invention also provides a composite functional bacterial agent prepared from the wheat fusarium biocontrol bacteria.

[0009] The present invention provides a strain with DON degradation function, the strain is classified and named Nocardioides sp. MOZ-1, and was deposited in the China Center for Type Culture Collection on December 5, 2024, with a preservation number of CCTCC NO: M 20242651.

[0010] The invention provides a biocontrol attenuated composite functional bacterial agent, comprising Bacillus subtilis DC-1 and Nocardia sp. MOZ-1, wherein the strain collection number of Bacillus subtilis DC-1 is CCTCC NO: M 20242397; the strain collection number of Nocardia sp. MOZ-1 is CCTCC NO: M 20242651.

[0011] Furthermore, the number of viable bacteria of Bacillus subtilis DC-1 in the biocontrol attenuated composite functional microbial agent was 0.7×10 8 -1.6×10 8 cfu / mL, and the viable count of Nocardia MOZ-1 was 0.4×10 6 -0.9×10 6 cfu / mL.

[0012] Preferably, the viable count of Bacillus subtilis DC-1 in the biocontrol attenuated composite functional bacterial agent is 0.7×10 8cfu / mL, and the viable count of Nocardia MOZ-1 was 0.4×10 6 cfu / mL.

[0013] A biocontrol and attenuated composite functional bacterial agent is used for agricultural biological control, which can not only prevent and control wheat fusarium rust, but also be used to degrade DON.

[0014] The total genome length of the biocontrol strain DC-1 was predicted to be 4,243,488 bp, with a GC content of 44.17%, 86 tRNAs and 30 rRNAs. Nr annotation showed that it was related to Bacillus ( Bacillus ) and Bacillus subtilis ( Bacillus subtilis ) has the most homologous sequences. KEGG annotation showed that the DC-1 genome contained a large number of metabolism-related genes, which had the ability to biosynthesize antimicrobial substances such as penicillin, cephalosporin, novobiocin, streptomycin, and validamycin, as well as metabolism pathways such as fructose, mannose, galactose, sucrose, starch, and fatty acid, indicating the potential mechanism of action of DC-1 in antagonizing pathogens and promoting plant growth.

[0015] The genome size of the DON-degrading strain MOZ-1 was predicted to be 5,223,092 bp with a GC content of 71.49%. 48 tRNAs and 6 rRNAs were predicted. Nr annotation showed that it was similar to Nocardia ( Nocardioides ) has the most homologous sequences. CAZy annotated the genome of strain MOZ-1 and found 42 enzymes or binding domains related to glucosyltransferases. Studies have shown that glucosyltransferases can glycosylate DON into low-reactivity products, blocking the contact between toxic groups and receptors to achieve detoxification.

[0016] Beneficial effects of the present invention: 1. The present invention separates a biocontrol bacterium DC-1 having a good control effect on wheat fusarium rust from a diseased wheat plant. The strain is identified as Bacillus subtilis DC-1 through morphological observation and 16S rRNA gene sequence analysis. The whole genome test of the strain shows that the genome of the biocontrol bacterium DC-1 has multiple pathways related to the synthesis of antimicrobial substances and metabolism, as well as related enzymes or binding domains for antagonizing pathogens, and has a good antagonistic effect on Fusarium graminearum. The biocontrol strain DC-1 has an inhibition rate of more than 60% on Fusarium graminearum PH-1 at 20-30°C and pH 5-9, and has the best antibacterial effect at 30°C and pH 5-8, with an inhibition rate of up to 70%. The inhibition rates of the sterile fermentation broth at 72h and 96h on Fusarium graminearum are 67.04% and 67.22%, respectively.

[0017] 2. The present invention isolated a strain of DON-efficient degrading bacteria from the soil of a diseased wheat field and identified it as Nocardioides sp. MOZ-1. The plate confrontation method was used to find that the strain MOZ-1 had no antagonistic effect with the biocontrol strain DC-1. Whole genome testing and analysis showed that the genome of the DON-degrading strain MOZ-1 had multiple enzymes or binding domains related to DON detoxification. The degradation strain MOZ-1 can degrade DON at 10-50°C and pH 6-9. The degradation efficiency is highest at 30°C and pH 7.0. The degradation rate is positively correlated with the inoculation amount, and the degradation rate of DON at different concentrations within 24 hours is as high as 95% or more.

[0018] 3. The present invention creatively develops a biocontrol attenuated composite functional bacterial agent based on Bacillus subtilis DC-1 and Nocardia sp. MOZ-1. The composite functional bacterial agent has strong antagonistic effect and low production cost, has a strong inhibitory effect on the infection of Fusarium graminearum, can reduce the use of chemical pesticides and reduce DON pollution, and is widely used in the field of agricultural biological control.

[0019] This composite functional bacterial agent not only enables the biocontrol strain DC-1 to successfully colonize on wheat plants, but also the combined treatment of the degradation strain MOZ-1 and the biocontrol strain DC-1 improves the disease resistance of wheat and inhibits the infection and DON synthesis of Fusarium graminearum. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The antagonistic effect of different wheat fusarium rust biocontrol bacteria on Fusarium graminearum PH-1.

[0021] Figure 2 These are the morphological characteristics of the wheat fusarium rust biocontrol strain DC-1.

[0022] Figure 3This is the HPLC chromatogram of DON degradation by Nocardia-like strain MOZ-1.

[0023] Figure 4 These are the morphological characteristics of the DON-degrading strain MOZ-1.

[0024] Figure 5 The inhibitory effect of different inoculation doses of strain DC-1 on Fusarium graminearum PH-1.

[0025] Figure 6 The inhibitory effect of the fermentation broth of strain DC-1 on Fusarium graminearum PH-1.

[0026] Figure 7 The degradation effect of strain MOZ-1 at different inoculation amounts on DON.

[0027] Figure 8 The antagonistic effects of single and combined treatments of strain MOZ-1 and strain DC-1 on Fusarium graminearum PH-1.

[0028] Fig. 9 The protective effect of single and combined treatments of strain MOZ-1 and strain DC-1 against Fusarium graminearum PH-1 on detached wheat leaves.

[0029] Fig.10 DON content in wheat leaves in vitro in the single and combined treatment groups of strain MOZ-1 and strain DC-1.

[0030] Fig.11 The protective effect of single and combined treatment of strain MOZ-1 and strain DC-1 against Fusarium graminearum PH-1 on wheat plants.

[0031] Fig.12 DON content in wheat plants treated with strain MOZ-1 and strain DC-1 alone and in combination.

[0032] Fig.13 This is the effect of single and combined treatments of DON-degrading strain MOZ-1 and biocontrol strain DC-1 on dominant genera of wheat bacteria. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further described below in conjunction with the embodiments, but it is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the protection scope of the present invention. The process equipment or devices not specifically noted in the following embodiments are all conventional equipment or devices in the art. If not specifically specified, the raw materials used in the embodiments of the present invention can be obtained commercially; if not specifically specified, the technical means used in the embodiments of the present invention are all conventional means well known to those skilled in the art. Example

[0034] Biocontrol bacteria Bacillus subtilis ( Bacillus subtilis Screening and identification of DC-1 Multiple bacterial strains were isolated and purified from diseased wheat ears by the dilution spread plate method and the plate streak method. The pathogen of wheat fusarium graminearum (Fusarium graminearum PH-1) was used as the indicator bacteria. Eight bacterial strains with antagonistic effects on wheat fusarium graminearum were obtained by the four-point plate confrontation method. Among them, the inhibition rate of strain DC-1 on Fusarium graminearum PH-1 reached 74.72% (such as Figure 1 ). The strain was then identified by morphological characteristics, physiological and biochemical characteristics and molecular biology.

[0035] (1) Morphological identification Use a sterilized toothpick to pick up a single colony of about 0.5 mm in size and place it in a centrifuge tube containing 50 µL of ultrapure water, and stir until it is semi-turbid. Use tweezers to take a piece of copper mesh with the front side facing up, and use a pipette to suck a trace amount of bacterial liquid on the front side of the copper mesh. After standing for a few seconds, use the rough edge of filter paper to absorb the excess liquid from the edge of the copper mesh. Then take a drop of 4% uranyl acetate dye and drop it on the copper mesh. After waiting for a few seconds, use filter paper to absorb the excess dye, and dry it naturally for 15 minutes. Use a JEOL JEM-1010 transmission electron microscope to observe the morphological characteristics of the strain.

[0036] The morphological characteristics of biocontrol strain DC-1 are as follows Figure 2 As shown, after culturing on the LB plate for 24 hours, the colonies were milky white with an opaque surface; under the conditions of voltage 80 kV and magnification 5000×, the strain DC-1 appeared as an oval rod with uniform coloring and flagella around it.

[0037] (2) 16S rRNA gene sequence analysis The DNA of the wheat fusarium scaly biocontrol strain DC-1 was used as a template, and the universal primers 27F / 1492R were used to amplify the 16S rRNA gene of the strain to be tested. The full-length sequence of the 16S rRNA gene was analyzed, and the Blast alignment was performed using NCBI. The homologous sequence information was downloaded, and the phylogenetic evolutionary tree was constructed using MEGA 11 software. 1000 random samplings were performed, and the confidence of the phylogenetic tree was evaluated by calculating the bootstrap value to determine the taxonomic status of the strain.

[0038] The 16S rRNA gene sequence of strain DC-1 is 1429 bp in length. It was compared with Bacillus subtilis ( Bacillus subtilis ) similarity reaches 100%, Example

[0039] Degrading bacteria Nocardia Nocardioides sp. MOZ-1) A single strain with DON degradation function was isolated from the soil of the diseased wheat field by the dilution spread plate method and the plate streak method. It was numbered as MOZ-1 and inoculated into MSM liquid culture medium containing DON as the only carbon source and energy source. After continuous cultivation for 24 hours, DON could no longer be detected by HPLC (such as Figure 3 ), indicating that strain MOZ-1 has the function of degrading DON with high degradation efficiency.

[0040] (1) Morphological identification The identification method is the same as in Example 1.

[0041] The morphological characteristics of the degradation strain MOZ-1 are as follows Figure 4 As shown in the figure, after 3 days of cultivation on the MSM plate with DON as the only carbon source and energy source, the colonies were white and translucent and difficult to observe. Under the conditions of voltage 80 kV and magnification 4000 ×x, it can be clearly observed that the strain MOZ-1 appears as a rod with strong staining at both poles.

[0042] (2) 16S rRNA gene sequence analysis The analysis method is the same as in Example 1.

[0043] The 16S rRNA gene sequence of the degradation strain MOZ-1 is 1393 bp in length. Blast comparison by NCBI revealed that it is similar to Nocardia ( Nocardioides ) The similarity reached 98.9%. Example

[0044] Effect of inoculum size on biocontrol efficacy of strain DC-1 The strain DC-1 was divided into 600 =0.2, 0.4, 0.6, 0.8, 1.0 inoculation amount for plate confrontation test, after 5 days of culture, the antagonistic effect on Fusarium graminearum was as follows Figure 5 As shown in the figure, the antagonistic effect of strain DC-1 on Fusarium graminearum was almost unaffected by the inoculation amount. The inhibition rates of strain DC-1 on Fusarium graminearum under different inoculation conditions were 71.43% (OD 600 =0.2), 71.45% (OD 600 =0.4), 71.81% (OD 600 =0.6)、72.20%(OD 600 =0.8), 72.59% (OD 600 =1.0), indicating that trace amounts of strain DC-1 can effectively antagonize Fusarium graminearum. Example

[0045] Biocontrol Effect of Sterile Fermentation Broth of Strain DC-1 on Fusarium graminearum The fermentation broths with different culture times were mixed with PDA medium to prepare mixed plates. After 5 days of culture, the growth of Fusarium graminearum was observed and the inhibition rate was calculated. The results are as follows: Figure 6 As shown, the sterile fermentation broth of strain DC-1 has a good inhibitory effect on Fusarium graminearum, among which the inhibition rates of the sterile fermentation broth at 72h and 96h are relatively high, reaching 67.04% and 67.22% respectively. After high-temperature sterilization, the fermentation broth of each group has almost no inhibitory effect on Fusarium graminearum, indicating that strain DC-1 has the potential to synthesize antagonistic substances to inhibit pathogens. Example

[0046] Effect of inoculum size on degradation efficiency of strain MOZ-1 MOZ-1 bacterial suspension was divided into 600 =0.2, 0.4, 0.6, 0.8, 1.0 inoculated in MSM liquid medium containing 1.0 mg / L DON, the degradation rate of DON is as follows Figure 7 As shown in the figure, with the increase of inoculation amount, the degradation rate of DON gradually increased. When the inoculation level reached OD 600 = 0.4, strain MOZ-1 could almost completely degrade 1 mg / LDON within 16 h. 600 =1.0, strain MOZ-1 could degrade more than 80% of DON within 10 h. Example

[0047] Antagonistic effects of biodegradation strain MOZ-1 and biocontrol strain DC-1 on Fusarium graminearum The degradation strain MOZ-1 and the biocontrol strain DC-1 were inoculated into LB liquid medium for propagation, washed and resuspended 3 times with PBS, and the OD of the bacterial solution was adjusted with PBS solution as blank control. 600 The inhibition rate was 0.4. 2 µL MOZ-1 solution, DC-1 solution and a composite solution of the two in equal proportions were evenly inoculated on PDA solid culture medium. Each treatment was repeated 3 times. The treatment inoculated with Fusarium graminearum cake alone was used as the control. The culture medium was inverted and cultured in the dark at 25°C incubator for 5 days. The fungal diameter was measured and the inhibition rate was calculated.

[0048] Antagonistic effects of single and combined treatments of degradation strain MOZ-1 and biocontrol strain DC-1 on Fusarium graminearum PH-1 Figure 8 As shown in the data, the degradation strain MOZ-1 had almost no inhibitory effect on Fusarium graminearum PH-1. The single treatment of biocontrol strain DC-1 and its combined treatment with the degradation strain MOZ-1 had a good inhibitory effect on Fusarium graminearum PH-1, with inhibition rates reaching 70.74% and 71.48%, respectively. Example

[0049] Experiment on the protective effect of degradation strain MOZ-1 and biocontrol strain DC-1 on detached wheat leaves Healthy leaves of the same size were cut from wheat plants with similar growth conditions, rinsed with 70% alcohol for 10 s, rinsed with sterile water three times, and dried in a clean bench. 600 = 0.4 MOZ-1 solution, DC-1 solution and composite solution were soaked for 1 min. After drying, the leaves were inoculated with 3 mm diameter Fusarium graminearum cake. Four wheat leaves were treated in each treatment, and three replicates were set up. Sterilized leaves were soaked in PBS solution as a control. The leaves were placed in an artificial climate incubator at 25°C and 80% relative humidity for culture. The results were observed after 3 days, and the DON content was determined by HPLC.

[0050] The detached leaves of wheat in different treatment groups were inoculated with Fusarium graminearum PH-1. The disease conditions after 3 days were as follows Fig. 9 As shown in the figure, the mycelium of the pathogen on the wheat leaves of the control group grew densely and extended along both ends of the leaves. The wheat leaves were yellow and dry, and there were water-soaked brown spots at the inoculation site of the fungus cake ( Fig. 9 A); Compared with the control group, the wheat leaves of the MOZ-1 single treatment group had fewer pathogenic fungi hyphae, but the leaves were still yellow and there were water-soaked brown spots at the inoculation site of the fungus cake ( Fig. 9 B); The hyphae of the pathogen on wheat leaves in the DC-1 single treatment group grew sparsely, with only a small amount of hyphae extending outwards, and some leaves were slightly yellow, while the whole leaf was green ( Fig. 9 C); In the wheat leaf treatment group of strain MOZ-1 and strain DC-1, the mycelium of pathogens basically did not grow, there were no obvious lesions, and the leaves were green and healthy overall ( Fig. 9 D).

[0051] DON content in wheat leaves in vitro treated with single and combined treatments of degradation strain MOZ-1 and biocontrol strain DC-1 Fig.10 As shown, the DON content in detached leaves of wheat in the control group was 2.07 µg / g, and the DON contents in detached leaves of wheat in the single and combined treatment groups of the degradation strain MOZ-1 and the biocontrol strain DC-1 were 0.8 µg / g (strain MOZ-1 single treatment), 1.21 µg / g (strain DC-1 single treatment) and 0.48 µg / g (strain MOZ-1 and strain DC-1 combined treatment), respectively. This indicates that the combined treatment of the degradation strain MOZ-1 and the biocontrol strain DC-1 can effectively prevent and control wheat fusarium and DON. Example

[0052] Experiment on the protective effect of degradation strain MOZ-1 and biocontrol strain DC-1 on wheat plants Select healthy wheat plants with consistent growth conditions, rinse them with 70% alcohol for 10 seconds, rinse them with sterile water three times, and dry them in a clean bench. 600 = 0.4 MOZ-1 solution, DC-1 solution and composite solution were soaked for 1 min, then taken out and dried. The wheat plants were punctured with a sterile syringe and inoculated with 3 mm diameter Fusarium graminearum cakes. Water-soaked sponges were inserted into the roots of the plants and replaced daily. Eight wheat plants were treated in each treatment with 3 replicates. The disinfected wheat plants were soaked in PBS solution as the control and moisturized. The plants were placed in an artificial climate incubator at 25°C and 80% relative humidity for 7 days and the results were observed. The DON content was determined by HPLC.

[0053] In order to explore the control effect of degradation strain MOZ-1 and biocontrol strain DC-1 on Fusarium graminearum PH-1 in living wheat plants, wheat plants in different treatment groups were inoculated with wounds, and the disease occurrence was observed after 7 days. Fig.11 As shown, the wheat plants in the control group were more seriously ill, with larger yellow-brown spots and a tendency to spread. Some of the pathogen hyphae penetrated the leaf surface ( Fig.11 A); Compared with the control group, the wheat plant symptoms in the MOZ-1 single treatment group were relatively alleviated, the leaves at the inoculation site turned yellow, and the lesions were small and scattered ( Fig.11 B); The wheat plants in the DC-1 single treatment group were less infected, with only a few small spots and no tendency to spread ( Fig.11 C); The wheat plants in the composite treatment group were in good condition, with only a small amount of mycelium infection on the wound surface, but no obvious lesions ( Fig.11 D). The results showed that strain MOZ-1 and strain DC-1 treatments could inhibit the infection of Fusarium graminearum to a certain extent, among which strain DC-1 had a stronger antagonistic effect on Fusarium graminearum, and showed good control effects under single treatment and combined treatment with MOZ-1.

[0054] The DON content of wheat plants in the single and combined treatment groups of the degradation strain MOZ-1 and the biocontrol strain DC-1 was as follows Fig.12 As shown, the DON content of wheat plants in the control group was 1.64 µg / g, and the DON contents of wheat plants in the single and combined treatment groups of the degradation strain MOZ-1 and the biocontrol strain DC-1 were 0.54 µg / g (strain MOZ-1 single treatment), 0.97 µg / g (strain DC-1 single treatment) and 0.32 µg / g (strain MOZ-1 and strain DC-1 combined treatment), respectively. The DON content in the combined treatment group was the lowest, indicating that the combined treatment of the degradation strain MOZ-1 and the biocontrol strain DC-1 had a good control effect on wheat fusarium and DON. Example

[0055] Analysis of wheat microbiome under treatment with degradation strain MOZ-1 and biocontrol strain DC-1 After 7 days of treatment of the wheat plants treated in Example 8, wheat samples from each group were collected, ground by liquid nitrogen and stored in a -80°C refrigerator. Three replicates were processed for each group, and the samples were subjected to 16S rRNA gene (V5-V7) high-throughput sequencing with primers 799F / 1193R. NovaSeq 6000 was used for PE250 sequencing. The data of each sample after the machine was split according to the Barcode sequence, and the Barcode sequence and PCR amplification primers were removed. The raw data was spliced ​​by Flash software, the redundant sequences were cut using Cutadapt software, and the Fastp software was used for filtering.

[0056] The DADA2 module in the QIIME2 software was used to denoise the effective data to obtain the final amplicon sequence variants (ASVs) and compare them with the Silva database for species annotation. The changes in the bacterial community structure were analyzed based on the species abundance at the bacterial genus level.

[0057] Select the top 20 dominant bacterial genera in relative abundance to draw a heat map. The results are as follows Fig.13 The dominant bacterial genera in wheat in each treatment group mainly included Pseudomonas Pseudomonas (29.48%-78.11%), Bacillus Bacillus (2.60%-49.75%), Stenotrophomonas Stenotrophomonas (0.39%-3.34%) and Nocardia Nocardioides (0.01%-2.77%), etc. Under the single treatment of degradation strain MOZ-1, Pseudomonas and Bacillus The relative abundance of Stenotrophomonas The relative abundance of MOZ-1 in the treated wheat decreased by 86.55% compared with that in the control group. Nocardioides The relative abundance was 2.77%, indicating that the degradation strain MOZ-1 could colonize on wheat. Pseudomonas and Bacillus The relative abundances of the degradation strain MOZ-1 and the control group increased to 1.27 and 19.14 times, respectively, and their changing trends were similar to those of the single treatment group with the degradation strain MOZ-1. Stenotrophomonas The relative abundance of the control group increased by 15.39%, showing a promoting effect. Nocardioides The same as the control group, basically no detection; under the combined treatment of degradation strain MOZ-1 and biocontrol strain DC-1, Pseudomonasand Bacillus The relative abundance of Stenotrophomonas The relative abundance of Nocardioides The relative abundance was detected in wheat at 1.01%, and was almost not detected in the control group.

[0058] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0059] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A wheat fusarium biocontrol bacterium, characterized in that: The biocontrol bacteria is classified and named Bacillus subtilis DC-1, and was deposited in the China Center for Type Culture Collection on November 7, 2024, with a deposit number of CCTCC NO: M 20242397.

2. A biocontrol agent for preventing and controlling wheat scab, characterized in that: The biocontrol agent includes the Bacillus subtilis DC-1 described in claim 1.

3. A DON-degrading strain, characterized in that: The strain was classified and named Nocardioides sp. MOZ-1, and was deposited in the China Center for Type Culture Collection on December 5, 2024, with the deposit number CCTCC NO: M20242651.

4. A biocontrol attenuated composite functional bacterial agent, characterized in that: The invention comprises Bacillus subtilis DC-1 and Nocardia sp. MOZ-1. The strain collection number of Bacillus subtilis DC-1 is CCTCC NO: M 20242397; the strain collection number of Nocardia sp. MOZ-1 is CCTCC NO: M 20242651.

5. The biocontrol attenuated composite functional bacterial agent according to claim 4, characterized in that: The viable count of Bacillus subtilis DC-1 is 0.7×10 8 -1.6×10 8 cfu / mL, and the viable count of Nocardia MOZ-1 was 0.4×10 6 -0.9×10 6 cfu / mL.

6. The biocontrol attenuated composite functional bacterial agent according to claim 4, characterized in that: The viable count of Bacillus subtilis DC-1 is 0.7×10 8 cfu / mL, and the viable count of Nocardia MOZ-1 was 0.4×10 6 cfu / mL.

7. Use of the biocontrol attenuated composite functional bacterial agent according to any one of claims 4 to 6 in agricultural biological control, characterized in that: The agricultural biological control is to use the biological control attenuated composite functional bacterial agent to control wheat fusarium and degrade DON.

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