Streptomyces angusticus and application thereof

Abstract

The invention discloses a strain of streptomyces angustifolius and application of the streptomyces angustifolius. The streptomyces angusticus disclosed by the invention is separated from banana rhizosphere soil, is named as a strain GD7-29, is preserved in the Guangdong Microbial Culture Collection Center on June 26, 2024, and has the preservation number of GDMCC No: 64803. The streptomyces angusticus disclosed by the invention has the advantages that the streptomyces angusticus is named as a strain GD7-29, and the preservation number is GDMCC No: 64803. The streptomyces narrow-mycin strain GD7-29 can effectively inhibit various plant pathogenic fungi including fusarium oxysporum, can promote plant growth, can be used for preventing and treating plant pathogenic fungus diseases, and particularly can be applied to preventing and treating banana fusarium wilt and promoting banana growth. The streptomyces narrow-mycin strain GD7-29 disclosed by the invention has a good application prospect in the aspects of preventing and treating plant fungal diseases and promoting plant growth.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological control of plant pathogens. More specifically, it relates to a strain of Streptomyces angustmyceticus and its application in controlling plant pathogenic fungal diseases and promoting plant growth, especially in controlling banana wilt disease and promoting banana growth. Background Art

[0002] Plant pathogenic fungi are one of the main pathogens causing plant diseases, which have brought adverse effects to various aspects such as agricultural production and ecological environment. For example, banana wilt disease is a soil-borne vascular disease caused by Fusarium oxysporum f. sp. cubense race 4 (Foc4). In severe cases, it will lead to the complete failure of banana crops, causing huge economic losses.

[0003] Biological control based on biocontrol bacteria is one of the effective control methods for plant fungal diseases, with the advantages of being green and safe. However, among the reported biocontrol bacteria, there are few strains that can not only have good inhibitory effects on a variety of plant pathogenic fungi including Fusarium oxysporum f. sp. cubense, but also promote plant growth. Therefore, it is still necessary to continuously explore biocontrol bacteria and enrich the microbial library to facilitate the development of actual products, and significantly reduce or avoid the harm caused by plant pathogenic fungi to agricultural production and so on. Summary of the Invention

[0004] In view of the above-mentioned deficiencies of the prior art, the present invention provides a strain of Streptomyces angustmyceticus, which not only has good inhibitory effects on a variety of plant pathogenic fungi including Fusarium oxysporum f. sp. cubense race 4, but also can effectively promote the growth of plants in the genus Musa.

[0005] The first object of the present invention is to provide a strain of Streptomyces angustmyceticus.

[0006] The second object of the present invention is to provide a microbial preparation.

[0007] The third object of the present invention is to provide the application of the Streptomyces angustmyceticus or the microbial preparation in inhibiting plant pathogenic fungi.

[0008] The fourth object of the present invention is to provide the application of the Streptomyces angustmyceticus or the microbial preparation in the preparation of a product for inhibiting plant pathogenic fungi.

[0009] The fifth object of the present invention is to provide the application of the Streptomyces angustmyceticus or the microbial preparation in controlling plant diseases caused by plant pathogenic fungi.

[0010] The sixth object of the present invention is to provide the application of the Streptomyces angustmyceticus or the microbial preparation in the preparation of a product for preventing and controlling plant diseases caused by plant pathogenic fungi.

[0011] The seventh object of the present invention is to provide the application of the Streptomyces angustmyceticus or the microbial preparation in promoting the growth of plants of the genus Musa.

[0012] The eighth object of the present invention is to provide the application of the Streptomyces angustmyceticus or the microbial preparation in the preparation of a product for promoting the growth of plants of the genus Musa.

[0013] The above objects of the present invention are achieved by the following technical solutions:

[0014] In the present invention, an antagonistic bacterium against Fusarium oxysporum f. sp. cubense race 4 (Foc4) was isolated from banana rhizosphere soil and named strain GD7-29. Through morphological, physiological and biochemical, molecular identification and detection of its antibacterial spectrum, it was found that the strain GD7-29 is a Streptomyces angustmyceticus strain, which can not only effectively inhibit the growth of Fusarium oxysporum f. sp. cubense race 4, but also effectively inhibit the growth of various plant pathogenic bacteria such as Corynespora cassiicola and Phyllosticta citricarpa, and can be developed into a plant pathogenic fungal inhibitor for the prevention and control of plant fungal diseases. In addition, the strain GD7-29 can also promote the growth of banana plants and has a significant growth-promoting effect. Therefore, the present invention requests protection of the strain and its application.

[0015] The present invention provides a strain of Streptomyces angustmyceticus, namely the strain GD7-29, which was deposited with the Guangdong Provincial Microbial Culture Collection Center on June 26, 2024, and the deposit number is GDMCC No: 64803.

[0016] Specifically, the nucleotide sequences of the 16S rDNA, gyrB, rpoB and trpB genes of the strain GD7-29 of the present invention are shown in SEQ ID NO.1 to 4 in sequence.

[0017] The present invention also provides a microbial preparation, which contains the Streptomyces angustmyceticus strain GD7-29.

[0018] Specifically, the preparation also contains the culture solution and / or culture supernatant of the Streptomyces angustmyceticus strain GD7-29.

[0019] Specifically, the culture solution or culture supernatant includes itself, its concentrate or its freeze-dried product.

[0020] The Streptomyces xiamenensis strain GD7-29 of the present invention has an inhibitory effect on the growth of various phytopathogenic fungi. Therefore, the present invention claims the application of the Streptomyces xiamenensis strain GD7-29 or the microbial preparation in inhibiting phytopathogenic fungi.

[0021] The present invention also claims the application of the Streptomyces xiamenensis strain GD7-29 or the microbial preparation in the preparation of a product for inhibiting phytopathogenic fungi.

[0022] Specifically, the phytopathogenic fungi are one or more of Fusarium oxysporum f. sp. cubense, Colletotrichum musae, Fusarium oxysporum f. sp. niveum, Fusarium oxysporum f. sp. melonis, Fusarium oxysporum f. sp. cucumermum, Fusarium solani, Alternaria alternata, Fusarium incarnatum, Fusarium oxysporum f. sp. benincasae, Fusarium oxysporum f. sp. lycopersici, Fusarium oxysporum f. sp. momordicae, Rhizoctonia solani, Corynespora cassiicola, and Fusarium graminearum.

[0023] Specifically, the Fusarium oxysporum f. sp. cubense includes race 4 and race 1 of Fusarium oxysporum f. sp. cubense.

[0024] The present invention also claims the application of the Streptomyces xiamenensis strain GD7-29 or the microbial preparation in controlling plant diseases caused by phytopathogenic fungi.

[0025] The present invention also claims the application of the Streptomyces xiamenensis strain GD7-29 or the microbial preparation in the preparation of a product for controlling plant diseases caused by phytopathogenic fungi.

[0026] Specifically, the plant pathogenic fungi are one or more of Fusarium oxysporum f. sp. cubense, Colletotrichum musae, Fusarium oxysporum f. sp. niveum, Fusarium oxysporum f. sp. melonis, Fusarium oxysporum f. sp. cucumerinum, Fusarium solani, Phyllosticta citricarpa, Fusarium incarnatum, Fusarium oxysporum f. sp. benincasae, Fusarium oxysporum f. sp. lycopersici, Fusarium oxysporum f. sp. momordicae, Rhizoctonia solani, Corynespora cassiicola, and Fusarium graminearum.

[0027] The present invention also claims the use of the Streptomyces angustmyceticus strain GD7-29 or the microbial preparation in promoting the growth of plants of the genus Musa.

[0028] The present invention also claims the use of the Streptomyces angustmyceticus strain GD7-29 or the microbial preparation in the preparation of a product for promoting the growth of plants of the genus Musa.

[0029] Specifically, the plant of the genus Musa is banana.

[0030] More specifically, the banana is Brazilian banana.

[0031] The present invention has the following beneficial effects:

[0032] The present invention provides a strain of Streptomyces angustmyceticus, which is isolated from the rhizosphere soil of banana, named strain GD7-29, and deposited in the Guangdong Microbial Culture Collection Center on June 26, 2024, with the deposit number GDMCC No: 64803.

[0033] The Streptomyces angustmyceticus strain GD7-29 of the present invention can effectively inhibit a variety of plant pathogenic fungi including Fusarium oxysporum f. sp. cubense, and can be developed into a plant pathogenic fungal inhibitor for preventing and controlling plant fungal diseases such as banana wilt. In addition, the Streptomyces angustmyceticus strain GD7-29 can also promote the growth of banana plants, and has good application prospects in the prevention and control of plant fungal diseases and the promotion of plant growth. Description of the Drawings

[0034] Figure 1 is the colony morphology of strain GD7-29.

[0035] Figure 2 is the observation result of the scanning electron microscope morphology of strain GD7-29.

[0036] Figure 3 is the phylogenetic tree constructed based on the 16S rDNA gene, gyrB gene, ropB gene, and trpB gene sequences of strain GD7-29.

[0037] Figure 4Inhibition of the growth of 15 plant pathogens, such as Fusarium oxysporum f. sp. cubense race 4, by strain GD7-29; the test bacteria from left to right in the figure are Fusarium solani, Colletotrichum musae, Fusarium graminearum, Rhizoctonia solani, Fusarium oxysporum f. sp. cubense race 4, Fusarium oxysporum f. sp. cubense race 1, Fusarium incarnatum, Fusarium oxysporum f. sp. lycopersici, Fusarium oxysporum f. sp. cucumerinum, Fusarium oxysporum f. sp. momordicae, Corynespora cassiicola, Fusarium oxysporum f. sp. niveum, Fusarium oxysporum f. sp. melonis, Fusarium oxysporum f. sp. cucumerinum, and Diaporthe citri.

[0038] Figure 5 Results of the effects of strain GD7-29 on the growth and hyphal morphology of Foc4; A in the figure is the colony of Foc4 growing normally; B in the figure is the hyphal morphology of Foc4 growing normally; C in the figure is the colony morphology of Foc4 inhibited by strain GD7-29; D in the figure is the hyphal morphology of Foc4 inhibited by strain GD7-29, where the arrow indicates abnormal hyphae.

[0039] Figure 6 Inhibition of the growth of Foc4 by the fermentation supernatant of strain GD7-29; A in the figure is the growth of Foc4 on the medium containing the fermentation supernatant of strain GD7-29 at different concentrations; B in the figure is the inhibition rate of the fermentation supernatant of strain GD7-29 at different concentrations on Foc4; different letters in the figure indicate significant differences, p < 0.05.

[0040] Figure 7 Results of the efficacy test of strain GD7-29 against banana wilt; A in the figure is the disease incidence of banana plants in the treatment group and the control group; B in the figure is the statistical result of the disease index of banana plants in the treatment group and the control group; different letters in the figure indicate significant differences, p < 0.05.

[0041] Figure 8 Results of the effects of strain GD7-29 on the growth of banana plants; A-D in the figure are the results of the effects of strain GD7-29 on the fresh weight, plant height, corm diameter, and relative chlorophyll content of banana plants in sequence; *p < 0.05; **p < 0.01; ns indicates no significant difference. Detailed implementation mode

[0042] The following further illustrates the present invention in conjunction with the accompanying drawings of the specification and specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the technical field.

[0043] Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0044] The formula of the culture medium used in the embodiments of the present invention is as follows. If it is necessary to prepare a solid culture medium, add 15 g of agar.

[0045] Gauze's No. 1 Medium: Soluble starch 20 g, KNO 3 1 g, MgSO 4 ·7H 2 O 0.5 g, NaCl 0.5 g, K 2 HPO 4 0.5 g, Fe 2 (SO 4 ) 3 0.01 g, deionized water 1000 mL, pH 7.4.

[0046] NA Medium: Beef extract 5 g, peptone 10 g, NaCl 5 g, deionized water 1000 mL, pH 7.4.

[0048] MS Medium: Mannitol 20 g, soybean cake powder 20 g, deionized water 1000 mL, pH 7.2.

[0049] ISP-2 Medium: Yeast extract 4 g, malt extract 10 g, glucose 4 g, deionized water 1000 mL, pH 7.3.

[0050] PDA Medium: Potato 200 g, glucose 20 g, agar 15 g, deionized water 1000 mL.

[0051] The formulations and usage methods of the media for determining the physiological and biochemical characteristics of the strains in the embodiments of the present invention are as follows:

[0052] Starch hydrolysis medium: Soluble starch 10 g, Nacl 0.5 g, MgCO 3 1 g, K 2 HPO 4 0.3 g, KNO 3 1 g, agar 15 g, deionized water 1000 mL, pH 7.2; after the strain is inoculated and cultured for 2 - 4 d, add Lugol's iodine solution dropwise on the plate. If the plate turns blue and there is a clear zone around the colony, it indicates that the starch is hydrolyzed, which is positive, otherwise it is negative.

[0053] Milk medium: Skim milk 1000 mL, CaCO 3 0.02 g, sterilize by intermittent boiling 5 times; continuously observe for 3 - 30 d after the strain is inoculated. If the phenomenon of solidification followed by liquefaction appears, it is positive, otherwise it is negative.

[0054] Cellulose hydrolysis medium: MgSO 4 0.5 g, K 2 HPO 4 0.5 g, NaCl 0.5 g, KNO3 1 g, 1000 mL of deionized water, pH 7.2; after the liquid medium was dispensed into test tubes, the cytiva filter paper was cut into uniform filter strips with a length of 6 cm and a width of 1 cm. After sterilization, the filter strips were added to the test tubes, with half immersed in the liquid and half exposed above the liquid surface. The cytiva filter paper was used as cellulose (carbon source); the strain was inoculated on the filter paper above the liquid surface, and observed continuously for 30 days. If the filter strip decomposed and fragmented, it was positive; otherwise, it was negative.

[0055] Esterase medium: 1 g of peptone, 5 g of NaCl, CaCl 2 ·7H 2 O 0.1 g, 20 g of agar, 1000 mL of deionized water, pH 7.2; after the strain was inoculated and cultured for observation for 3 - 7 days, if a clear halo appeared around the bacterial cells, it was positive; otherwise, it was negative.

[0056] Urease medium: KH 2 PO 4 10 g, Na 2 HPO 4 9.5 g, 1 g of yeast extract, 20 mL of 0.04% phenol red, 1000 mL of deionized water, pH 7.2. After sterilization, 10 mL of filtered and sterilized 15% urea was added; after the liquid medium was mixed and dispensed into test tubes, the strain was inoculated and cultured for observation for 28 days. If the solution changed from orange - yellow to magenta, it was positive; otherwise, it was negative.

[0057] Nitrate reduction medium: MgSO 4 0.5 g, KNO 3 1 g, 0.5 g of NaCl, K 2 HPO 4 0.5 g, 20 g of sucrose, 1000 mL of deionized water; after the strain was inoculated and cultured for observation for 7 - 14 days, Griess reagent and aniline reagent were added to the medium. If the solution turned red, it was positive. If it did not change, another portion of the solution was taken and aniline reagent was added. If the solution did not change, it was positive; if it turned blue, it was negative.

[0058] The taxonomic name of the strain GD7 - 29 described in the embodiments of the present invention is Streptomyces angustmyceticus. The strain was deposited at the Guangdong Provincial Culture Collection of Microorganisms on June 26, 2024, with the deposit number GDMCC No: 64803, and the deposit address is on the 5th floor of the Experimental Building, No. 100 Compound, Xianlie Middle Road, Yuexiu District, Guangzhou City, Guangdong Province.

[0059] The banana used in the embodiments of the present invention is Brazilian banana.

[0060] Obtaining of the strain GD7 - 29 in Example 1

[0061] The strain GD7-29 described in the present invention is an antagonist of Fusarium oxysporum f. sp. cubense race 4 (Foc4), and its obtaining process is as follows:

[0062] 1. Isolation and purification of the strain

[0063] The dilution coating method was used to isolate single colonies and the continuous streaking method was used for purification;

[0064] Take the rhizosphere soil of bananas in the banana orchard, and make it into sample solutions with concentrations of 10 -2 、10 -3 、10 -4 and 10 -5 with sterile water. Absorb 100 μL and evenly coat it on the NA solid medium, and culture it at 28 °C for 5 d; the continuous streaking method was used to purify the strain to obtain single colonies.

[0065] 2. Screening of the antagonist

[0066] The five-point confrontation method was used to screen the antagonist;

[0067] Take a Foc4 bacterial cake (5 mm in diameter) and inoculate it in the center of the PDA plate medium. In a "plus" shape, inoculate the bacterial cake (5 mm in diameter) of the single colony obtained by the above separation and purification 2.5 cm away from the Foc4 bacterial cake. Use the PDA medium inoculated only with the Foc4 bacterial cake as a control, and culture it upside down at 28 °C for 5-7 d; calculate the growth inhibition rate of each single colony obtained by separation and purification against Foc4, and preserve the strain with the relatively best growth inhibition rate, named GD7-29;

[0068] Growth inhibition rate = (control colony diameter - treated colony diameter) / (control colony diameter - bacterial cake diameter) × 100%, and each treatment was repeated 3 times.

[0069] Example 2 Identification of strain GD7-29

[0070] 1. Observation of the morphological characteristics of strain GD7-29

[0071] Inoculate the preserved strain GD7-29 on the Gao's No. 1 solid medium and culture it at 28 °C for 7 d to observe its colony morphology. At the same time, use a scanning electron microscope to observe the cell morphology of strain GD7-29.

[0072] The colony morphology of strain GD7-29 is as shown in Figure 1 . Combining Figure 1 it can be seen that the surface of the colony of strain GD7-29 is dry, the edge is irregular, and it does not secrete pigments.

[0073] The scanning electron microscope morphological observation results of strain GD7-29 are as shown in Figure 2 shown. CombiningFigure 2 It can be seen that the strain GD7-29 has hyphal structures and spores. Its spore chains are spirally clustered on the conidiophores, the spores are round or nearly spherical (diameter less than 1 μm), and the hyphae are branched.

[0074] 2. Determination of the physiological and biochemical characteristics of strain GD7-29

[0075] The preserved strain GD7-29 was inoculated into media containing different carbon sources respectively to observe the utilization of different carbon sources by strain GD7-29. Separately, strain GD7-29 was inoculated into starch hydrolysis medium, milk medium, cellulose hydrolysis medium, esterase medium, urease medium, and nitrate reduction medium, and cultured in the dark for 7 - 30 d to complete the determination of the physiological and biochemical characteristics of strain GD7-29.

[0076] The results of the determination of the physiological and biochemical characteristics of strain GD7-29 are shown in Table 1. In the table, \"+\" indicates a positive result, \"-\" indicates a negative result, and \"W\" indicates a weakly positive result.

[0077] Table 1 Physiological and biochemical characteristics of strain GD7-29

[0078]

[0079] 3. Molecular identification of strain GD7-29

[0080] The genomic DNA of strain GD7-29 was extracted using a bacterial DNA extraction kit. Using the extracted genomic DNA as a template, its 16S rDNA gene sequence was amplified by PCR respectively. The primer sequences for PCR amplification of the gene are shown in Table 2; the PCR amplification system is: 1 μL of DNA template, 1 μL of upstream primer, 1 μL of downstream primer, 4 μL of dNTP mixture, 0.25 μL of Ex Taq enzyme, 5 μL of ExTaq Buffer, and ddH 2 O was added to make up 50 μL; the PCR amplification program for amplifying 16S rDNA is: 95°C for 5 min; 94°C for 30 s, 58°C for 30 s, 72°C for 10 min, for 35 cycles; the PCR amplification program for amplifying gyrB, rpoB, and trpB is: 95°C for 5 min; 94°C for 30 s, 65°C for 30 s, 72°C for 10 min, for 30 cycles.

[0081] After the PCR amplification was completed, the PCR amplification products were sent to the company for sequencing. The sequencing results were aligned with sequences in the NCBI database, and a phylogenetic tree was constructed using the Neighbor-Joining method of MEGA7.0.

[0082] Table 2 Primer sequences for PCR amplification of the gene

[0083]

[0084] Sequencing showed that the nucleotide sequences of the 16S rDNA, gyrB, rpoB, and trpB genes of strain GD7-29 were as shown in SEQ ID NO.1 to 4 in sequence. The phylogenetic tree constructed by combining the 16S rDNA, gyrB, rpoB, and trpB gene sequences of strain GD7-29 was as Figure 3 shown. The results of BLAST alignment analysis showed that the sequence similarity between strain GD7-29 and Streptomyces angustmyceticus (>NZ_CP104317.1) was 99.4%; at the same time, the phylogenetic tree ( Figure 3 ) analysis results showed that strain GD7-29 clustered with Streptomyces angustmyceticus with a similarity of 100%. Combining the results of morphological, physiological and biochemical characteristics and phylogenetic tree analysis, strain GD7-29 was identified as Streptomyces angustmyceticus and preserved.

[0085] The strain GD7-29 of the present invention was deposited at the Guangdong Provincial Microbial Culture Collection Center on June 26, 2024, with the deposit number GDMCC No: 64803, and the deposit address is on the 5th floor of the Experimental Building, No. 100, Xianlie Middle Road, Yuexiu District, Guangzhou City, Guangdong Province.

[0086] Example 3 Inhibitory effect of strain GD7-29 on the growth of different pathogenic bacteria

[0087] In this example, a total of 15 plant pathogenic bacteria, namely Fusarium oxysporum f. sp. momordicae, Fusarium oxysporum f. sp. benincasae, Fusarium oxysporum f. sp. lycopersici, Fusarium oxysporum f. sp. niveum, Fusarium oxysporum f. sp. melonis, Fusarium oxysporum f. sp. cucumerinum, Fusarium solani, Fusarium graminearum, Fusarium incarnatum, Corynespora cassiicola, Colletotrichum musae, Rhizoctonia solani, Fusarium oxysporum f. sp. cubense race 4, Fusarium oxysporum f. sp. cubense race 1, and Phyllosticta citricarpa, were used as test bacteria, and the inhibitory effect of strain GD7-29 on the growth of the above plant pathogenic bacteria was observed by the plate confrontation culture method (five-point method) and the inhibition rate was calculated.

[0088] The test method was as follows: Use a punch (5 mm in diameter) to punch out the bacterial cakes of each test bacterium and place them in the center of the PDA medium. Drop 5 μL of the spore suspension of strain GD7-29 (concentration of 1×10 8 CFU / mL) at a distance of 2.5 cm from the bacterial cake. After the plate was air-dried, it was sealed and cultured upside down at 28 °C for 7 d; the inhibition rate calculation method was: inhibition rate = (control group diameter - treatment group diameter) / (control group diameter - bacterial cake diameter) × 100%; each treatment was repeated 3 times.

[0089] The inhibitory effects of strain GD7-29 on the growth of 15 plant pathogens such as Fusarium oxysporum f. sp. cubense race 4 are as follows Figure 4 shown, and the corresponding inhibition rate calculation results are shown in Table 3.

[0090] Table 3 Inhibition rates of strain GD7-29 against 15 plant pathogens

[0091]

[0092] Different lowercase letters shown after the inhibition rates in the table indicate significant differences (p < 0.05).

[0093] In addition to observing the inhibitory effect of strain GD7-29 on the growth of Fusarium oxysporum f. sp. cubense race 4, the morphological observation of Foc4 hyphae at the confrontation edge was also carried out in this example.

[0094] The effects of strain GD7-29 on the growth and hyphal morphology of Foc4 are as follows Figure 5 shown; Figure 5 A in it is the Foc4 colony growing normally; Figure 5 B in it is the hyphal morphology of Foc4 growing normally; Figure 5 C in it is the colony morphology of Foc4 inhibited by strain GD7-29; Figure 5 D in it is the hyphal morphology of Foc4 inhibited by strain GD7-29, and the arrow indicates abnormal hyphae. It can be seen from Figure 5 that strain GD7-29 has an obvious inhibitory effect on the growth of Foc4. By observing the hyphae of Foc4 growing normally and the inhibited Foc4 under a microscope, it is found that when Foc4 grows normally, the hyphae are thick and uniform, with good integrity and continuity ( Figure 5 B in it), while after confrontation culture with strain GD7-29, the hyphae of the inhibited Foc4 are deformed ( Figure 5 D in it), indicating that strain GDD7-29 has an inhibitory effect on the growth of Foc4 hyphae.

[0095] Example 4 Inhibitory effect of the fermentation supernatant of strain GD7-29 on the growth of Foc4

[0096] 1. Preparation of fermentation supernatant

[0097] The spore suspension of strain GD7-29 was added to ISP-2 liquid medium to make its final concentration 1×10 6 CFU / mL, and cultured with shaking at 28 °C and 180 rpm for 7 d to obtain fermentation culture solution; the fermentation culture solution was centrifuged at 6000 rpm for 10 min, and then the supernatant was filtered through a 0.22 μm bacterial filter to obtain the fermentation supernatant.

[0098] 2. Inhibitory Test of Fermentation Supernatant on the Growth of Foc4

[0099] Add the prepared fermentation supernatant to the PDA medium cooled to 45°C to make its final concentrations (v / v) 5%, 10%, and 20% respectively; drop 5 μL of Foc4 spore suspension (concentration: 1×10 5 CFU / mL) at the center of the PDA medium plate containing different concentrations of the fermentation supernatant of strain GD7-29. The control is to drop an equal amount of Foc4 spore suspension in the blank PDA medium. Incubate at 28°C for 6 d, measure the hyphal diameter, calculate the inhibition rate, and repeat each treatment 3 times;

[0100] Inhibition rate = (diameter of the control group - diameter of the treatment group) / diameter of the control group × 100%.

[0101] The inhibitory effect of the fermentation supernatant of strain GD7-29 on the growth of Foc4 is as Figure 6 shown; Figure 6 A in is the growth of Foc4 on the medium containing different concentrations of the fermentation supernatant of strain GD7-29; Figure 6 B in is the inhibition rate of different concentrations of the fermentation supernatant of strain GD7-29 on Foc4. From the Figure 6 results shown, it can be seen that the fermentation supernatant of strain GD7-29 has an obvious inhibitory effect on the growth of Foc4. When the volume percentage of the fermentation supernatant is 5%, its inhibition rate on Foc4 is 41.6%; when the volume percentage of the fermentation supernatant is 10%, its inhibition rate can reach 60.0%; when the volume percentage of the fermentation supernatant is 20%, its inhibition rate can reach 70.8% ( Figure 6 B in ).

[0102] Example 5. Efficacy Detection of Strain GD7-29 against Banana Fusarium Wilt

[0103] 1. Preparation of Spore Suspension

[0104] Inoculate strain GD7-29 into the Gao's No. 1 liquid medium and culture at 28°C and 180 rpm / min for 2 d; take 100 μL of the culture solution and spread it on the MS solid medium, culture at 28°C for 7 d, add sterile water, and filter with a 200-mesh cell sieve to obtain the spore suspension of the antagonistic bacterium GD7-29.

[0105] 2. Pot Experiment on Control Efficacy

[0106] Transplant the Brazilian banana seedlings into flower pots containing 150 g of sterilized nutrient soil, and inoculate them after growing to the 4-leaf stage. Treatment group T1: Pour 50 mL of the spore suspension of strain GD7-29 into the rhizosphere of the banana seedlings (the final concentration of spores is 1×10 8CFU / g soil), after 2 days, root injury treatment was carried out around the banana pseudostem at a distance of 2.5 cm, and then 50 mL of Foc4 spore suspension (final spore concentration of 1×10 5 CFU / g soil) was added. After 5 days of Foc4 inoculation, 50 mL of spore suspension of strain GD7-29 was inoculated again. Control group 1: Only 50 mL of clear water was inoculated; Control group 2: Only 50 mL of Foc4 spore suspension (final spore concentration of 1×10 5 CFU / g soil) was inoculated; 30 banana seedlings were inoculated for each treatment, and the investigation was carried out 28 days after inoculation with Foc4, and each treatment was repeated 3 times; the disease grading standard referred to the method of Huang Yonghui (2016) (Table 4).

[0107] Table 4 Disease grading standard for banana Fusarium wilt (Huang Yonghui, 2016)

[0108]

[0109] The calculation methods of disease index and control effect are as follows: Disease index = (number of diseased plants in each grade × grade value) / (total number of banana seedlings × highest grade) × 100; Control effect (%) = (disease index of control - disease index of antagonistic bacterium treatment) / disease index of control × 100%.

[0110] The detection results of the control effect of strain GD7-29 on banana Fusarium wilt are as Figure 7 shown; Figure 7 A in it is the disease incidence of banana plants in the treatment group and control groups 1 and 2; Figure 7 B in it is the statistical result of the disease index of the treatment group and control group 2. It can be Figure 7 seen that after pretreatment of Brazilian banana plants with the spore suspension of strain GD7-29, its incidence and disease index were significantly reduced, indicating that strain GD7-29 has a significant effect on the prevention and control of banana Fusarium wilt. Among them, after treatment with ddH 2 2O for 2 days and then inoculation with Foc4, the incidence of Brazilian banana reached 95.1%, and the disease index was 80.8. After pretreatment with the spore suspension of strain GD7-29, the disease index of Brazilian banana decreased to 35.7, and the control effect reached 55.8%. The above results indicate that strain GD7-29 has a good control effect on banana Fusarium wilt.

[0111] Example 6 Growth-promoting effect of strain GD7-29 on bananas

[0112] The root irrigation method was used for treatment. The Brazilian banana seedlings were transplanted into flower pots containing 150 g of sterilized nutrient soil and inoculated after growing to the 4-leaf stage. Treatment group T: 50 mL of spore suspension of strain GD7-29 was poured into the rhizosphere of banana seedlings (final spore concentration of 1×10 8(CFU / g soil). After 7 days of inoculation, 50 mL of the spore suspension of strain GD7-29 (final spore concentration of 1×10 8 (CFU / g soil) was inoculated again. Control group CK: Only 50 mL of clear water was inoculated; 30 banana seedlings were inoculated in each treatment. After 30 days of inoculation with Foc4, the fresh weight, plant height, corm diameter, and relative chlorophyll content of the bananas were investigated to detect whether strain GD7-29 had a growth-promoting effect on bananas.

[0113] The results of the effect of strain GD7-29 on banana growth are as Figure 8 shown. Figure 8 In A-D in [figure number not provided], they are the results of the effect of the spore suspension of strain GD7-29 on the fresh weight, plant height, corm diameter, and relative chlorophyll content of bananas respectively. From Figure 8 the results shown, it can be seen that after treatment with strain GD7-29, the fresh weight, plant height, corm, and relative chlorophyll content of the bananas increased significantly, by 23.3%, 14.2%, 15.2%, and 6.5% respectively, indicating that strain GD7-29 has a significant growth-promoting effect on the overall growth of bananas.

[0114] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent substitution methods and are all included in the protection scope of the present invention.

Claims

1. A strain of Streptomyces angustmyceticus, characterized in that: The Streptomyces serrata strain was deposited in the Guangdong Provincial Microbiological Culture Collection Center on June 26, 2024, with the collection number GDMCC No: 64803.

2. A microbial preparation, characterized in that: Contains the Streptomyces streptomyces strain described in claim 1.

3. The microbial preparation according to claim 2, characterized in that: It also contains the culture solution and / or culture supernatant of the Streptomyces streptomyces strain described in claim 1.

4. The microbial preparation according to claim 3, characterized in that: The culture solution or culture supernatant includes the culture solution itself, a concentrate thereof or a lyophilized product thereof.

5. Use of the Streptomyces stenosis mycotoxins described in claim 1 or the microbial preparation described in any one of claims 2 to 4 in inhibiting plant pathogenic fungi, characterized in that: The plant pathogenic fungi are one or more of banana wilt pathogen, banana anthracnose pathogen, watermelon wilt pathogen, melon wilt pathogen, cucumber wilt pathogen, fusarium wilt pathogen, citrus brown spot pathogen, red fusarium pathogen, wax gourd wilt pathogen, tomato wilt pathogen, bitter melon wilt pathogen, Rhizoctonia solani, cucumber target spot pathogen, and graminearum Fusarium.

6. Use of the Streptomyces stenosis mycelialgensis according to claim 1 or the microbial preparation according to any one of claims 2 to 4 in the preparation of a product for inhibiting plant pathogenic fungi, characterized in that: The plant pathogenic fungi are one or more of banana wilt pathogen, banana anthracnose pathogen, watermelon wilt pathogen, melon wilt pathogen, cucumber wilt pathogen, fusarium wilt pathogen, citrus brown spot pathogen, red fusarium pathogen, wax gourd wilt pathogen, tomato wilt pathogen, bitter melon wilt pathogen, Rhizoctonia solani, cucumber target spot pathogen, and graminearum Fusarium.

7. Use of the Streptomyces stenosis mycotoxins described in claim 1 or the microbial preparation described in any one of claims 2 to 4 in preventing and controlling plant diseases caused by plant pathogenic fungi, characterized in that: The plant pathogenic fungi are one or more of banana wilt pathogen, banana anthracnose pathogen, watermelon wilt pathogen, melon wilt pathogen, cucumber wilt pathogen, fusarium wilt pathogen, citrus brown spot pathogen, red fusarium pathogen, wax gourd wilt pathogen, tomato wilt pathogen, bitter melon wilt pathogen, Rhizoctonia solani, cucumber target spot pathogen, and graminearum Fusarium.

8. Use of the Streptomyces stenosis mycelialgensis according to claim 1 or the microbial preparation according to any one of claims 2 to 4 in the preparation of a product for preventing and controlling plant diseases caused by plant pathogenic fungi, characterized in that: The plant pathogenic fungi are one or more of banana wilt pathogen, banana anthracnose pathogen, watermelon wilt pathogen, melon wilt pathogen, cucumber wilt pathogen, fusarium wilt pathogen, citrus brown spot pathogen, red fusarium pathogen, wax gourd wilt pathogen, tomato wilt pathogen, bitter melon wilt pathogen, Rhizoctonia solani, cucumber target spot pathogen, and graminearum Fusarium.

9. Use of the Streptomyces stenosis mycelialgenus described in claim 1 or the microbial preparation described in any one of claims 2 to 4 in promoting the growth of plants of the genus Musa.

10. Use of the Streptomyces stenosis mycelialgenus described in claim 1 or the microbial preparation described in any one of claims 2 to 4 in the preparation of a product for promoting the growth of plants of the genus Musa.

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