Biocontrol actinomycetes for preventing and treating wolfberry root rot and application thereof

Abstract

The invention belongs to the technical field of microbial pesticides, and particularly relates to biocontrol actinomycetes for preventing and treating Chinese wolfberry root rot and application of the biocontrol actinomycetes. The biocontrol actinomycete for preventing and treating the Chinese wolfberry root rot is streptomyces flavonoids NA05, the preservation number of the biocontrol actinomycete is CGMCC (China General Microbiological Culture Collection Center) No.29739, the preservation date of the biocontrol actinomycete is January 23, 2024, and the preservation address of the biocontrol actinomycete is China General Microbiological Culture Collection Center. The streptomyces flavonoids NA05 has a remarkable inhibition effect on various pathogenic bacteria of the root rot of the Chinese wolfberry, can regulate and control the root micro-ecology of the diseased Chinese wolfberry to resist the occurrence of the root rot, and is expected to be used for developing targeted drugs and biocontrol agents for treating the root rot of the Chinese wolfberry.

Description

Technical Field

[0001] The invention belongs to the technical field of microbial pesticides, and particularly relates to a biocontrol actinomycete for preventing and controlling wolfberry root rot and an application thereof. Background Art

[0002] Lycium barbarum L. is a perennial deciduous shrub of the genus Lycium in the Solanaceae family. It is a traditional Chinese medicinal material in my country and occupies an important position in the development of Chinese medicine. In recent years, the occurrence of wolfberry diseases has become more serious year by year. Among them, root rot is one of the main diseases in the cultivation of Ningxia wolfberry, causing great losses to production and seriously restricting the sustainable development of the industry. There are many types of pathogens for wolfberry root rot. The occurrence of plant root rot is often caused by a combination of multiple pathogens. The types of pathogens for Ningxia wolfberry root rot are gradually increasing with the renewal of wolfberry varieties and changes in planting methods. Chemical agents have a certain effect on the prevention and control of root rot, but the effect is not good; in addition, excessive addition may change the properties of the soil, and more seriously may damage the soil and ecological environment, and the safety hazards cannot be ignored. Biological control has received increasing attention due to its advantages such as good effect, low cost, high efficiency, environmental friendliness and no drug residue.

[0003] A large number of microbial resources gather in the rhizosphere of plants, many of which have the functions of promoting growth and biocontrol. The key point in the study of biological control of wolfberry root rot is to obtain microbial resources with strong inhibitory effects on wolfberry root rot pathogens from the rhizosphere of wolfberry. At present, there are many types of antagonistic microorganisms used for plant disease control, including actinomycetes, Bacillus and Pseudomonas, but there are few reports on antagonistic bacteria specifically for wolfberry root rot. The existing reports are mainly bacteria and fungi, including Bacillus amyloliquefaciens, Sinorhizobium sp., Metarhizium sp., Rhizophagus intraradices, etc.; there are few reports on the antagonism of actinomycetes against wolfberry root rot pathogens. Actinomycetes produce rich secondary metabolites, which can effectively inhibit bacteria, fungi, viruses and nematodes that harm crops. They are the earliest biocontrol microorganisms used in actual production and have important value in biological control. Obtaining microbial resources for the prevention and control of root rot from the rhizosphere of wolfberry is of great significance for the prevention and control of wolfberry root rot. It can effectively solve the problem of efficient colonization of key microorganisms in microbial agents and the ecological safety risks caused by the introduction of alien species. Antagonistic screening against a variety of wolfberry pathogens can also ensure the prevention and control effect of microbial agents on root rot. Summary of the invention

[0004] In view of the deficiencies in the prior art, the object of the present invention is to provide a biocontrol actinomycete for preventing and treating wolfberry root rot and its application.

[0005] To achieve the purpose of the invention, the present invention adopts the following technical scheme: a biocontrol actinomycete for preventing and controlling wolfberry root rot, the biocontrol actinomycete for preventing and controlling wolfberry root rot is Streptomyces flavofungini (S. flavofungini) NA05, the biocontrol actinomycete for preventing and controlling wolfberry root rot is Streptomyces flavofungini (S. flavofungini) NA05, the preservation number is CGMCC No. 29739, the preservation date is January 23, 2024, and the preservation address is the General Microbiology Center of China Microorganism Culture Collection Administration.

[0006] In some embodiments of the present invention, the Streptomyces flavus NA05 has an earthy smell, the colonies are opaque, and the surface of the colonies is dry.

[0007] On the other hand, the present invention provides the use of the biocontrol actinomycetes for preventing and controlling wolfberry root rot in preventing and controlling wolfberry root rot. The aflatoxin-resistant Streptomyces NA05 has a significant inhibitory effect on the pathogenic fungi of wolfberry root rot.

[0008] In some embodiments of the present invention, the biocontrol actinomycetes for preventing and controlling wolfberry root rot are used in preventing and controlling wolfberry root rot, and the pathogenic fungi of wolfberry root rot include Rhizoctonia solani, Fusarium oxysporum, Fusarium odoriferum, Fusarium solani, Fusarium rubrum, Fusarium erythrorhizium, and Pink Spiral Synechocystis.

[0009] In some embodiments of the present invention, the biocontrol actinomycetes for preventing and controlling wolfberry root rot are used in preventing and controlling wolfberry root rot, and the conidia of the aflatoxin-resistant Streptomyces NA05 are used as the effective ingredient directly or processed into a preparation for preventing and controlling wolfberry root rot.

[0010] In some embodiments of the present invention, the biocontrol actinomycetes for preventing and controlling wolfberry root rot are used in preventing and controlling wolfberry root rot, and the preparation includes liquid bacterial agent, powder, granule, etc.

[0011] On the other hand, the present invention provides an application of the biocontrol actinomycetes for preventing and controlling wolfberry root rot in improving the stability of the microecological community structure. The aflatoxin-resistant Streptomyces NA05 is used in the soil of diseased wolfberries, so that the abundance of pathogens in the rhizosphere and root surface of wolfberries is significantly reduced, and the abundance of beneficial bacteria is significantly increased.

[0012] The beneficial effects of the present invention are:

[0013] (1) The biocontrol actinomycetes for preventing and controlling wolfberry root rot provided by the present invention are Streptomyces flavofungini (S. flavofungini) NA05, which has a significant inhibitory effect on various pathogens of root rot. The effective effect of strain NA05 against wolfberry root rot was verified by potted plant experiments.

[0014] (2) The biocontrol actinomycetes (S. flavofungini) NA05 for preventing and controlling wolfberry root rot provided by the present invention has a significant inhibitory effect on the growth of mycelium of various pathogenic fungi after high-temperature sterilization, with the highest antibacterial efficiency reaching 70%.

[0015] (3) The introduction of NA05 into the soil has a positive regulatory effect on the community structure of bacteria and fungi in the rhizosphere and root surface of wolfberry, which can significantly reduce the abundance of pathogens in the rhizosphere and root surface soil of wolfberry, while significantly increasing the abundance of beneficial bacteria.

[0016] It can be seen that strain NA05 has a significant inhibitory effect on various pathogens of wolfberry root rot. Its active metabolites can withstand high temperatures, regulate the soil microecology of wolfberry, and resist the occurrence of root rot. It is expected to be developed into a targeted drug and biocontrol agent for the treatment of wolfberry root rot. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0018] Figure 1 : Colony morphology of strain NA05 on different culture media;

[0019] Figure 2 : Phylogenetic tree constructed based on gene sequences such as rRNA, atpD, recA, gyrB, rpoB, and trpB;

[0020] Figure 3 :Inhibitory effects of strain NA05 and its 3d and 5d fermentation broth on the growth of pathogenic fungi;

[0021] Figure 4 :Pot experiment verifies the control effect of strain NA05 on wolfberry root rot;

[0022] Figure 5 :Door level( Figure 5 a. Figure 5 b) and genus level ( Figure 5 c. Figure 5 d) Composition and relative abundance of fungi on the epi-root surface and in the rhizosphere;

[0023] Figure 6 :Door level( Figure 6 a. Figure 6 b) and genus level ( Figure 6 c. Figure 6 d) Composition and relative abundance of bacteria on the root surface and in the rhizosphere. DETAILED DESCRIPTION

[0024] The scheme of the present invention will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used are not indicated by the manufacturer and are all conventional products that can be obtained commercially.

[0025] The invention provides a biocontrol actinomycete for preventing and treating wolfberry root rot, wherein the biocontrol actinomycete for preventing and treating wolfberry root rot is Streptomyces flavofungini (S. flavofungini) NA05, the biocontrol actinomycete for preventing and treating wolfberry root rot is Streptomyces flavofungini (S. flavofungini) NA05, the preservation number is CGMCC No.29739, the preservation date is January 23, 2024, and the preservation address is the General Microbiology Center of China National Committee for the Preservation of Microorganisms.

[0026] In order to solve the shortcomings of the existing methods for preventing and controlling wolfberry root rot, the present invention uses more than 10 pathogens of wolfberry root rot, such as Rhizoctonia solani, Fusarium oxysporum, F. redolens, F. solani, F. proliferatum, F. incarnatum, F. andiyazi, F. moniliforme, Clonostachys rosea, etc. as test pathogenic fungi, and isolates and screens actinomycete NA05 with good antagonism to multiple pathogens of wolfberry root rot from the rhizosphere soil of Ningqi No. 1 wolfberry. Then, the taxonomic status of strain NA05 was identified as flavofungini by physiological and biochemical indicators and 16SrRNA, gyrB, trpB, recA, rpoB, and atpD multi-gene fragments. The inhibitory effects of NA05 fermentation broth on the growth of pathogenic bacteria mycelium under different treatments were compared, and it was proved that its antibacterial substances had a certain heat resistance. The positive regulatory effect of the strain on the composition and diversity of microbial communities in the rhizosphere and root surface soil of wolfberry was clarified, which expanded more microbial strain resources for the biological control of wolfberry root rot.

[0027] Preferably, the method is as follows: strain NA05 is inoculated into TSB medium, cultured at 28°C, 150r / min for 7d, the fermentation broth is centrifuged at 8000r / min for 5min, and the obtained supernatant is filtered with a 0.22μm microporous filter membrane to obtain a sterile fermentation filtrate; the fermentation broth is sterilized at 121°C for 30min, the sterile fermentation broths obtained by the two treatments are added to the culture medium, a plate prepared by mixing 2×PDA and ordinary TSB in a ratio of 1:1 is used as a control group, and after inoculating pathogens, the colony diameter is measured by the cross method, and the inhibition rate of each fermentation broth on the pathogenic hyphae is calculated.

[0028] The extracellular metabolites of the antagonistic bacteria NA05 play an important role in inhibiting pathogens ( Figure 3 ).

[0029] The antagonistic bacteria NA05 and the pathogenic bacteria are simultaneously inoculated into the wolfberry plants, which can inhibit or slow down the occurrence of wolfberry root rot and improve the symptoms of wolfberry root rot ( Figure 4 ).

[0030] The antagonistic bacteria NA05 is inoculated into the soil of wolfberry potting, which can regulate the rhizosphere microecology of wolfberry and resist the occurrence of root rot ( Figure 5 , Figure 6 , Table 3, Table 4).

[0031] Preferably, firstly, potted experiments are used to verify that the introduction of NA05 strains will inhibit the occurrence of wolfberry root rot or alleviate the symptoms of wolfberry root rot; secondly, high-throughput sequencing technology is used, and after the introduction of strain NA05 and pathogens at the same time, the diversity indexes such as the Shannon index of wolfberry root surface and rhizosphere fungi are better than those of the control group inoculated with only pathogens, and the diversity of root surface bacteria is also better than that of the control group inoculated with only pathogens. This is mainly reflected in the fact that after the simultaneous inoculation of strain NA05 and pathogens, the abundance of Fusarium in the wolfberry roots is significantly reduced, and the abundance of beneficial bacteria such as Mortierella and Bacillus increases.

[0032] Example 1: Isolation and identification of Streptomyces flavus NA05

[0033] 1. Isolation and purification of rhizospheric actinomycetes

[0034] The rhizosphere soil sample of Ningqi No. 1 wolfberry was collected in 2021, with a tree age of more than 20 years. The coordinates of the collection site are: 37°32′21″N, 105°40′27″E. The circumference of the sample tree root is 30 cm and the ground diameter is 9.55 cm. After digging out the whole plant, shake off the soil on the root, and use a sterile brush to carefully brush the rhizosphere soil of the healthy root onto sterile newspaper. The collected rhizosphere soil is the rhizosphere soil, which is stored at low temperature and used for the isolation of rhizosphere actinomycetes as soon as possible. The collected rhizosphere soil is sieved through a 20-mesh sieve, 10 g is weighed and put into 90 mL of sterile water to prepare a bacterial suspension, placed in a constant temperature shaker at 150 r / min for 2 hours, and then allowed to stand for 1 hour. The supernatant is taken and diluted into 5 gradient concentrations according to the concentration gradient dilution method. 100 μL of the dilution solution of each concentration gradient is respectively aspirated and applied to the culture medium plate, and each gradient is repeated 3 times, and placed in a constant temperature incubator at 28°C for 3 days. Observe the growth of the colonies on the plate, number the colonies with different characteristics such as colony morphology, color and transparency, and pick them to purify on new WL-50 medium plates, repeat more than 5 times until pure culture is obtained. Pick the purified actinomycete colonies and culture them in TSB liquid medium at 150r / min for 3 days, and store them at -20℃ with 60% glycerol at a ratio of 1:1.

[0035] Figure 1 The colony morphology of strain NA05 on different culture media. NA05 has an earthy smell, the colonies are opaque and have a dry surface, and the colonies on different culture media are bright in color.

[0036] 2. Classification and identification of actinomycete NA05

[0037] The activated strain NA05 was used for experiments on physiological and biochemical characteristics such as nitrate reducing ability, starch hydrolysis, peroxidase production, gelatin liquefaction, melanin production, H2S production, tryptophan decomposition, and cellulose decomposition. The taxonomic status of NA05 was determined from the physiological and biochemical characteristics of the strain. The activated actinomycetes were inoculated in TSB liquid culture medium and cultured at 28°C and 150r / min for 3 days. The total DNA was extracted using a bacterial genomic DNA extraction kit. The genomic DNA was used as a template for PCR amplification of multiple gene fragments such as 16SrRNA, gyrB, and trpB. The PCR reaction system (50μL) was: 25μL Taq PCR Master Mix solution, 2μL upstream and downstream primers, 2μL template, and ddH2O was added to 50μL. The gene amplification program was: 94℃ pre-denaturation for 4min, 94℃ denaturation for 40s, 55℃ annealing for 45s, 72℃ extension for 1min, a total of 30 cycles, 72℃ extension for 8min, and storage at 4℃. The PCR products were separated by 1% agarose gel at 100V, and the amplification was checked by gel imaging. The qualified PCR products were sent to Sangon Biotech (Shanghai) Co., Ltd. for sequencing. The obtained sequences were analyzed and compared using the BLAST tool in GenBank, and the sequences with high similarity were downloaded as reference sequences. The phylogenetic tree was constructed using the NJ method in Mega5.0. The phylogenetic tree constructed for the NA05 strain based on the colony morphology, physiological and biochemical characteristics of the strain and the multi-gene sequence was finally identified as S. flavofungini.

[0038] Table 1 Physiological and biochemical indicators of strain NA05

[0039] project lactose D-Mannitol Galactose Adonitol maltose Xylitol Cellobiose Inositol result + + - - + + - - project Tryptophan breakdown L-Rhamnose sucrose glucose Arabinose fructose Raffinose sorbose result - + + + - - + - project Gelatin liquefaction Milk peptonization Nitrate reduction melanin Hydrogen sulfide Starch hydrolysis Peroxidase Cellulose hydrolysis result + + + - + - + -

[0040] Figure 2 Phylogenetic trees constructed based on 16S rRNA, atpD, recA, gyrB, rpoB, and trpB multi-gene sequences. Figure 2 The results in Table 1 show that the antagonistic bacteria NA05 is taxonomically identified as S. flavofungini, i.e., Streptomyces flavofungini, based on physiological and biochemical indices combined with multi-gene fragment identification.

[0041] Example 2: Inhibitory effect of Streptomyces NA05 on root rot pathogens

[0042] 1. Materials and Methods

[0043] 1.1 Experimental Materials

[0044] The root rot pathogens isolated and identified by our laboratory from the rotten roots of wolfberry include: Fusarium solani H203, Fusarium rubra H103, Fusarium solani H101, Fusarium odoratum QT205, Fusarium odoratum QT114, Fusarium oxysporum QX206, Fusarium solani QX106, Fusarium solani QT205, etc.

[0045] 1.2 Culture medium

[0046] PDA culture medium: 200 g / L peeled potatoes, boil for 20-30 min, filter the clarified liquid with gauze, add 20 g / L glucose to the clarified liquid, divide it into fixed volumes, add 20 g / L agar (divided in advance), and sterilize it in an autoclave at 115°C for 30 min.

[0047] WL-50 medium: yeast extract 1g / L, soluble starch 5g / L, sodium chloride 2.5g / L, magnesium sulfate 3.6g / L, L-alanine 0.2g / L, L-arginine 0.2g / L, L-asparagine 0.5g / L, magnesium chloride 4.8g / L, agar powder 20g / L, sterilize in an autoclave at 115°C for 30min.

[0048] TSB medium: 5 g / L yeast powder, 15 g / L tryptone, 5 g / L soy peptone, 5 g / L sodium chloride, sterilized in an autoclave at 121°C for 20 min.

[0049] 2. Experimental Methods

[0050] 2.1 Determination of antibacterial activity of strain NA05

[0051] The root rot pathogen was activated and cultured on a PDA plate, and a pathogen cake was punched out with a hole puncher with a diameter of 8 mm for later use. The pathogen cake was inoculated in the center of the WL-50 plate, and NA05 was inoculated symmetrically on both sides 1 cm away from the cake; the control group was inoculated with pathogens only. Each group was treated with 3 replicates and cultured at a constant temperature of 28°C. When the mycelium of the pathogen in the control group covered the plate, the corresponding diameter was observed and measured to calculate the antibacterial rate of each strain through the formula, and the average value was taken for comparison and evaluation.

[0052] Bacterial inhibition rate (%) = (control group diameter - treatment group diameter) / (control group diameter - bacterial cake diameter) × 100%

[0053] 2.2 Determination of the growth inhibition of pathogenic fungi by the fermentation broth of strain NA05

[0054] NA05 was inoculated into TSB medium, cultured at 28℃ and 150r / min for 7d, and the fermentation broth was centrifuged at 8000r / min for 5min. The supernatant was filtered with a 0.22μm microporous filter membrane in a clean bench to obtain a sterile fermentation filtrate. The sterile filtrate was mixed with 2×PDA sterilized and cooled to 50-60℃ in a ratio of 1:1, and about 20mL was poured into each culture dish to obtain a sterile fermentation filtrate plate. The water vapor was dried for standby use, which was treatment group 1. According to the above method, the plate prepared by adding an equal amount of fermentation broth sterilized at 121℃ for 30min was set as treatment group 2. The plate prepared by mixing 2×PDA and ordinary TSB in a ratio of 1:1 was used as the control group. The test pathogenic fungi were inoculated at the center of each group of culture medium plates. Each sample was repeated 3 times and cultured at a constant temperature of 28°C. Measurements and photos were taken on the 3rd and 5th days, and the colony diameters were measured using the cross method. The inhibition rate of each fermentation broth on pathogenic fungal hyphae was calculated according to the formula.

[0055] Mycelium inhibition rate (%) = (control group diameter - treatment group diameter) / (control group diameter - fungus cake diameter) × 100%

[0056] 3. Experimental results

[0057] 3.1 Inhibitory effect of strain NA05 on pathogens

[0058] In the plate confrontation experiment, strain NA05 had a significant inhibitory effect on the growth of seven wolfberry root rot pathogens. Strain NA05 had the strongest inhibitory effect on Rhizoctonia solani, with an inhibition rate of up to 89.9%, but had a weaker inhibitory effect on Fusarium solani.

[0059] 3.2 Inhibitory effect of the fermentation broth of strain NA05 on the mycelial growth of pathogenic bacteria

[0060] Table 2 Antibacterial rate of fermentation broth after different treatments (5d)

[0061]

[0062] In the two treatments of filtration sterilization and high temperature sterilization in Table 2, the inhibition rate of the high temperature sterilization filtrate on different pathogens was slightly lower than that of the filtration sterilization filtrate. Among them, the fermentation broth of strain NA05 had the best inhibitory effect on Rhizoctonia solani QX106, all above 70%; the inhibition rate on Fusarium solani was the lowest, about 30%; the inhibitory effect on other fungi was also obvious, and the inhibitory effect on pathogens under the two treatments was almost the same, which not only indicated that there were antibacterial substances against the pathogens of wolfberry root rot outside the cells, but also suggested that some antibacterial substances had certain temperature stability.

[0063] The strain NA05 has a significant inhibitory effect on multiple root rot pathogens, including Rhizoctonia solani QX106, Fusarium oxysporum QX206, Fusarium odoratum QT114, Fusarium solani H203, Fusarium rubrum H103, Fusarium lamina H101, and Fusarium rosenbergii QT205, with the inhibition rate being above 60% ( Figure 3 A); the 7-day fermentation broth had a significant inhibitory effect on the growth of pathogenic fungal hyphae after high-temperature sterilization and sterile filtration, with the highest inhibition rate reaching 74.8% ( Figure 3 B).

[0064] Example 3: Prevention and treatment of wolfberry root rot by Streptomyces flavus NA05 and its microecological regulation

[0065] 1. Materials and Methods

[0066] 1.1 Study on the control of wolfberry root rot by strain NA05

[0067] Two-year-old bare-root seedlings of Ningqi No. 5 wolfberry were transplanted into pots with a diameter of 25 cm at room temperature using sterilized mixed soil (sand soil: nutrient soil: coconut bran = 1:1:1) and managed until the plant growth was stable. A single colony of strain NA05 was inoculated into a 100 mL TSB shake bottle and cultured at 28 ° C and 150 r / min for 4 days. 100 mL of NA05 bacterial suspension was inoculated using the root irrigation method, and 100 mL of TSB was inoculated in the blank group; 10 days later, the treatment group was inoculated with 100 mL of Fusarium oxysporum QX206 and 100 mL of NA05 bacterial suspension at the same time, and the blank group was inoculated with 100 mL of Fusarium oxysporum QX206 bacterial suspension and 100 mL of TSB medium, with 5 replicates per group, and plant changes were observed and recorded on the 5th and 15th days after inoculation of the pathogen.

[0068] 1.2 Study on the regulation of rhizosphere microecology of wolfberry by strain NA05

[0069] Fifteen days after inoculation, the wolfberry plants were carefully pulled out to expose their roots and collect rhizosphere soil samples and root tissues of the two groups of wolfberries. About 30 g of rhizosphere soil from three plants in the same treatment group were collected, sealed, labeled, stored at low temperature and used for rhizosphere microbial community structure analysis, labeled as GJ-CK and GJ-NA05 respectively. The root tissue was incubated twice in a sterile phosphate buffer solution at 180 r / min at 4°C for 20 min, and the washing liquid was collected and combined. Centrifuged at 10000 r / min for 10 min, the precipitate was collected, and the root surface samples were obtained, labeled as GB-CK and GB-NA05 respectively.

[0070] 2. Experimental results

[0071] 2.1 Control effect of strain NA05 on root rot

[0072] Compared with the control group inoculated with pathogens only, the symptoms of wolfberry root rot were significantly alleviated or even disappeared after the strain NA05 was inoculated at the same time, indicating that strain NA05 has a significant control effect on wolfberry root rot ( Figure 4 ).

[0073] 2.2 Regulatory effect of strain NA05 on the microecology of wolfberry

[0074] Table 3 Diversity index of rhizosphere and root surface fungi

[0075] sample Chao Shamnon ACE Simpson Sobs Coverage / % oGJ-CK 299.98±18.17C 0.24±0.04c 314.25±24.22b 0.94±0.01a 266±22.34c 99.9 GJ-NA05 410.96±31.70b 0.35±0.02c 410.60±25.95b 0.92±0.01a 323±12.17b 99.9 GB-CK 354.54±102.07bc 0.63±0.21b 377.28±99.79b 0.80±0.05b 288±91.79bc 99.9 GB-NA05 579.91±6,77a 1.11±0.17a 595.75±16,47a 0.71±0.05c 509.67±12.05 99.9

[0076] Table 4 Alpha diversity index of rhizosphere and root surface bacteria

[0077] sample Chao Shamnon ACE Simpson Sobs Coverage / % GJ-CK 4777.62±168.54ab 5.41±0.20b 5074.49±255.72ab 0.05±0.01a 3322.±168.89bc 99.9 GJ-NA05 4486.98±247.37b 5.43±0.02b 4714.70±298.97b 0.06±0.00a 3174.33±104.16c 99.9 GB-CK 4775.42±362.51ab 6.21±0.11a 5053.07±389.41ab 0.02±0.00b 3529.33±212.74ab 99.9 GB-NA05 5104.58±104.14a 6.07±0.18a 5384.11±90.64a 0.03±0.01b 3616.67±73.10a 99.9

[0078] Note: Data are all mean ± standard deviation, different letters indicate significant differences (p < 0.05)

[0079] The results in Tables 3 and 4 show that compared with GJ-NA05 and GB-NA05, after the inoculation of strain NA05, the diversity indexes of Chao, Shannon, ACE, Simpson, and Sobs of rhizosphere and root surface fungi of wolfberry plants in GJ-CK and GB-CK were significantly higher than those in the control group. In the community structure composition, the relative abundance of the beneficial bacterium Mortierella increased significantly, and the relative abundance of the pathogenic bacterium Fusarium decreased significantly; in the bacterial community composition, the relative abundance of antagonistic microorganisms such as Pseudomonas and Bacillus increased, indicating that strain NA05 can effectively resist the occurrence of wolfberry root rot caused by Fusarium, and can recruit more beneficial microorganisms to maintain a healthy microecological environment in the rhizosphere of wolfberry. Figure 5 and Figure 6 The composition and relative abundance of root surface and rhizosphere fungi and bacteria at the phylum level and genus level. The antagonistic bacteria NA05 is inoculated into the wolfberry potted soil, which can regulate the rhizosphere microecology of wolfberry and resist the occurrence of root rot.

[0080] In summary, the strain NA05 (S. flavofungini) obtained in this study has a significant inhibitory effect on various pathogens of root rot; the sterile filtrate and high-temperature sterilized filtrate of strain NA05 have an inhibitory effect on the growth of mycelium of various pathogenic fungi, with the highest inhibitory efficiency reaching 70%; the potted experiment verified the effective effect of strain NA05 against wolfberry root rot, and the inoculated strain NA05 has a regulatory effect on the community diversity of rhizosphere bacteria and fungi in wolfberry. Streptomyces NA05 fights against wolfberry root rot not only by secreting extracellular antibacterial substances, but also by adjusting the community structure of soil microorganisms.

[0081] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A biocontrol actinomycete for preventing and treating wolfberry root rot, characterized in that: The biocontrol actinomycetes for preventing and controlling wolfberry root rot are Streptomyces flavofungini (S. flavofungini) NA05, with a preservation number of CGMCC No. 29739, a preservation date of January 23, 2024, and a preservation address of the General Microbiology Center of the China Microbiological Culture Collection Administration.

2. The biocontrol actinomycete according to claim 1, characterized in that The Streptomyces flavus NA05 has an earthy smell, the colonies are opaque, and the surface of the colonies is dry.

3. The biocontrol actinomycetes according to claim 1, characterized in that The genome size of the flavone-resistant Streptomyces NA05 is 9548746 bp, and the GC content is 72.12%, which is a high GC microorganism.

4. Use of the biocontrol actinomycetes for preventing and controlling wolfberry root rot according to any one of claims 1 to 3 in preventing and controlling wolfberry root rot, characterized in that: The flavone-resistant Streptomyces NA05 has a significant inhibitory effect on the pathogenic fungi of wolfberry root rot.

5. The use according to claim 4, characterized in that The pathogenic fungi of wolfberry root rot include Rhizoctonia solani, Fusarium oxysporum, Fusarium odoratum, Fusarium solani, Fusarium rubrum, Fusarium laminarum, and Polysporum rosiglita.

6. The use according to claim 4, characterized in that The conidia of the flavone-resistant Streptomyces NA05 are used as effective ingredients directly or processed into a preparation for preventing and controlling wolfberry root rot.

7. The use according to claim 6, characterized in that The preparations include liquid bacterial preparations, powders and granules.

8. Use of the biocontrol actinomycetes for controlling wolfberry root rot according to any one of claims 1 to 3 in regulating the structure and diversity of rhizosphere microbial communities of wolfberry, characterized in that: The aflatoxin-resistant Streptomyces NA05 was used in diseased wolfberry soil, which significantly reduced the abundance of wolfberry root rot pathogens and significantly increased the abundance of beneficial bacteria.

9. Use of the biocontrol actinomycetes for controlling wolfberry root rot according to any one of claims 1 to 3 in regulating the structure and diversity of rhizosphere microbial communities of wolfberry, characterized in that: The flavone-resistant Streptomyces NA05 is used to induce wolfberry to produce systemic resistance.

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