A Streptomyces strain, microbial agent and application for antagonizing phytopathogenic bacteria

Abstract

The present invention discloses a Streptomyces strain, a bacterial agent and an application for antagonizing plant disease pathogens. The Streptomyces strain for antagonizing plant disease pathogens is Streptoverticillium reticulum ADY-13, which is deposited in the China Center for Type Culture Collection with the deposit number CCTCC NO: M20241487; the deposit date is July 4, 2024. The strain and its metabolites for antagonizing plant disease pathogens in the present invention can antagonize the pathogens of potato late blight and konjac southern blight, and thus can achieve the prevention and control of potato late blight and konjac southern blight.

Description

Technical Field

[0001] The invention relates to the technical field of microorganisms, and in particular to a Streptomyces strain, a bacterial agent and an application thereof for antagonizing plant disease pathogens. Background Art

[0002] In actual production, the fermentation liquid of biocontrol bacteria can be used as a biological pesticide to replace traditional chemical pesticides, thereby reducing environmental pollution and the problem of chemical residues in potato and konjac products. Therefore, the fermentation liquid of biocontrol bacteria has broad application prospects in potato and konjac cultivation.

[0003] Potato late blight in Guizhou is a soil-borne disease caused by Phytophthora. It has broken out year after year, and prevention and control is costly and difficult. For a long time, passive prevention and control has been the main method. In addition, konjac white rot and soft rot also cause serious damage to konjac. It is reported that white rot is caused by Sclerotium rolfsii. When white rot occurs, water-soaked brown spots appear at the base of the petiole above the ground. Two days later, white hyphae will grow around the diseased area. After 10 days, a circle of white filaments can be formed around the petiole, and spherical or irregular brown sclerotia will be produced, which will cause the konjac plant to fall over. For the prevention and control of potato late blight and konjac white rot, chemical control is still the main control measure with the fastest effect. However, well-known control agents are expensive, and with the increase of pathogen resistance, the prevention effect of the agents is getting lower and lower, the amount of drugs used is increasing, and the cost of drugs is increasing year by year. At the same time, a large amount of residues are caused, which pollutes the environment and is not conducive to the sustainable development of the ecological environment. The use of chemical agents to control potato late blight faces problems such as cost reduction, reduced efficiency and ecological safety.

[0004] In addition, the application of chemical agents and fertilizers can also directly or indirectly affect the quality of crops; current studies have shown that the use of the chemical agent clofoconazole can significantly reduce the formation of peanut white rot fungi, and the higher the concentration of clofoconazole, the greater the reduction in nutrient content. In addition, the effect of exogenous application of chlorine on the growth of konjac, when the concentration is high, will significantly reduce its single plant yield and product quality. In addition, when studying the bulbil konjac, the application of different types of fertilizers on the market has an impact on the intrinsic indicators and nutritional components of the underground tubers of konjac.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a Streptomyces strain, a bacterial agent and an application thereof for antagonizing plant disease pathogens. The strain can antagonize potato late blight pathogens and konjac white rot pathogens, thereby achieving the prevention and treatment of potato late blight and konjac white rot.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0008] In the first aspect of the present invention, a Streptomyces strain antagonistic to plant disease pathogens is provided. The Streptomyces strain antagonistic to plant disease pathogens is Streptoverticillium reticulum ADY-13, which is deposited in the China Center for Type Culture Collection with the deposit number CCTCC NO: M20241487; the deposit date is July 4, 2024.

[0009] Preferably, the plant disease pathogens include the pathogen of potato late blight and the pathogen of konjac southern blight.

[0010] In the second aspect of the present invention, a bacterial agent containing the Streptomyces strain antagonistic to plant disease pathogens is provided.

[0011] In the third aspect of the present invention, an application of the Streptomyces strain antagonistic to plant disease pathogens in the preparation of a preparation for preventing and treating potato late blight and / or konjac southern blight is provided.

[0012] In the fourth aspect of the present invention, an application of the metabolite of the Streptomyces strain antagonistic to plant disease pathogens in the preparation of a preparation for preventing and treating potato late blight and / or konjac southern blight is provided.

[0013] In the fifth aspect of the present invention, a preparation for preventing and treating potato late blight and / or konjac southern blight is provided. The preparation includes the Streptomyces strain antagonistic to plant disease pathogens and / or the metabolite of the Streptomyces strain antagonistic to plant disease pathogens.

[0014] Preferably, the metabolite of the Streptomyces strain antagonistic to plant disease pathogens is obtained by fermentation culture and filtration sterilization of the Streptomyces strain antagonistic to plant disease pathogens.

[0015] In the sixth aspect of the present invention, a method for preventing and treating potato late blight and / or konjac southern blight is provided. The method includes drenching the roots of potatoes and / or konjac with the metabolite of the Streptomyces strain antagonistic to plant disease pathogens.

[0016] In the seventh aspect of the present invention, an application of the strain of the plant disease pathogen antagonist and / or the metabolite of the Streptomyces strain antagonistic to plant disease pathogens in increasing the starch and glucomannan contents in konjac is provided.

[0017] In the eighth aspect of the present invention, a method for the starch and glucomannan contents in konjac is provided. The method includes drenching the roots of konjac with the metabolite of the Streptomyces strain antagonistic to plant disease pathogens.

[0018] Compared with the prior art, the beneficial effects of the present invention at least include:

[0019] The strains and their metabolites of the present invention that antagonize plant disease pathogens can antagonize the pathogens of potato late blight and konjac southern blight, and thus can achieve the prevention and control of potato late blight and konjac southern blight. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0021] Figure 1 It is a phylogenetic tree of strain ADY-13 and related species in Example 1 of the present invention;

[0022] Figure 2 It is the morphological characteristics of strain ADY-13 in Example 1 of the present invention;

[0023] Figure 3 It is the growth inhibitory effect of strain ADY-13 on Pc and JC in Example 2 of the present invention;

[0024] Figure 4 It is the effect of the fermentation broth of strain ADY-13 on Pc and JC in Example 2 of the present invention;

[0025] Figure 5 It is the texture profile with a detection speed of 60 mm / min in Example 4 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will describe in detail the embodiments of the technical solutions of the present invention in combination with the embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and therefore are only examples and cannot be used to limit the protection scope of the present invention.

[0027] It should be noted that unless otherwise specified, the technical terms or scientific terms used in this application should have the ordinary meaning understood by those skilled in the art to which the present invention belongs.

[0028] Example 1

[0029] This example is the screening and identification of Streptomyces ADY-13;

[0030] I. Strain isolation and preservation

[0031] Three soil samples were collected from the rhizosphere of tea plants in Xiajiuxi Village, Daxiqiao Town, Xixiu District, Anshun City, Guizhou Province (26°17'26”, 106°8'18”) using the five-point method; Actinomycetes were isolated by the soil dilution coating method, named ADY-13, and stored at 4°C and -20°C with sterile water and 25% glycerol respectively; it is currently preserved in the China Center for Type Culture Collection, with the preservation number CCTCC NO: M20241487 and the preservation date of July 4, 2024.

[0032] II. Identification of Streptomyces ADY-13

[0033] 1. Phylogenetic analysis

[0034] 1.1 Genomic DNA extraction was carried out according to the instructions. For PCR amplification and detection, using 16s-F (5′-AGAGTTTGATCCTGGCTCAG-3′) and 16s-R (5′-GGTTACCTTGTTGTTACGACTT-3′) as primers, the 16S rRNA gene was amplified from the actinomycetes genomic template respectively. The PCR reaction system (25 μL): Premis TaqTM (0.05 U / μL) 12.5 μL, template DNA (about 20 ng / μL) 2 μL, upstream and downstream primers (10 μmol / L) 1 μL each, and ddH2O was added to make up 25.0 μL; ddH2O was used as the template DNA for the negative control. PCR reaction conditions (16S rRNA): 94°C for 5 min; 95°C for 1 min, 58°C for 30 s, 72°C for 90 s, 30 cycles; 72°C for 10 min. After the PCR results were detected by 1% agarose gel electrophoresis, it was entrusted to Beijing Tsingke Biotechnology Co., Ltd. for sequencing.

[0035] 1.2 Sequence analysis and phylogenetic tree construction. The sequenced sequences were subjected to homology retrieval through BLSATAn in GenBank and EzBioCloud (http: / / eztaxon-e.ezbiocloud.net / ), sequence alignment was performed using MAFFT, closely related sequences were downloaded (Table 1), sequence trimming was performed using the BioEdit software, and a phylogenetic tree was constructed using MEGA.

[0036] Table 1

[0037]

[0038] The 16s RNA of strain ADY-13 was obtained by PCR amplification. After sequencing, the 16s RNA sequence was obtained, and Blast alignment was performed using NCBI. For sequences with relatively high homology, the software MEGA was used to construct a phylogenetic tree (as Figure 1 shown).

[0039] 2. Morphological characteristics

[0040] Prepare the Gao's No. 1 medium containing 0.05 g / L potassium dichromate for standby. Under sterile conditions, streak inoculate the strain ADY-13 on the medium, and culture it at a constant temperature of 28 °C for 7-14 days. Regularly observe the colors of aerial hyphae and substrate mycelia, and at the same time pay attention to whether there is soluble pigment produced on the medium. The morphological characteristics of substrate mycelia, spore chains, and spores of the strain ADY-13 on the Gao's No. 1 medium were observed and photographed by the method of inserting slices. The morphological characteristics of the mycelia of the strain ADY-13 were observed by scanning electron microscopy.

[0041] Cultivate in an incubator at a constant temperature for 7-14 d, and observe the colony morphology of the strain ADY-13 on the Gao's No. 1 medium. Initially, a smooth, round, white colony is formed (such as Figure 2 A in the figure), and it becomes dry and wrinkled later. The substrate mycelia have a distinguishable ginger-yellow color, and no water-soluble pigment is produced; there is a musty smell. The spore filaments are straight and flexuous, and after the spore filaments are formed, they form a reticulated and branched morphology (such as Figure 2 B in the figure). The morphological characteristics observed by scanning electron microscopy are as shown in (such as Figure 2 C in the figure). The strain ADY-13 was subjected to Gram staining and was a Gram-positive bacterium (such as Figure 2 D in the figure).

[0042] In summary, the results of phylogenetic analysis showed that the 16S rRNA sequence of the strain ADY-13 was on the same branch as the sequence of Streptoverticillium reticulum, with a similarity of 94%. Combining with the morphological characteristics, the strain ADY-13 was identified as S. reticulum.

[0043] Example 2

[0044] This example is about the antagonistic effects of Streptomyces sp. ADY-13 against the pathogen of potato late blight (denoted as Pc, and the specific strain is Phytophthora infestans YM2309) and the pathogen of konjac southern blight (denoted as JC, and the specific strain is Sclerotium rolfsii JC-B-2):

[0045] Inoculate the pathogen cake (D = 6 mm) in the center of the PDA plate, and inoculate the purified strain ADY-13 cake 2 cm parallel and equidistant from the top, bottom, left, and right. Use only inoculating the pathogen as a control, and set 3 replicates for each treatment to clarify the competitive effects of Streptomyces sp. ADY-13 against the pathogen of potato late blight and the pathogen of konjac southern blight.

[0046] According to the ratio of inoculating a 6-mm-diameter bacterial cake into 10 mL of beef extract peptone liquid medium (LB), culturing at a constant temperature of 28 °C and 180 rpm / min with constant shaking for 7 days, then filtering to remove hyphae, centrifuging at 7830 rpm for 10 min on a centrifuge to obtain the supernatant, and finally filtering through a 0.22-μm disposable filter to prepare the fermentation broth of spores and hyphae of Streptomyces sp. ADY-13 for standby. Mix the original fermentation filtrate of Streptomyces sp. ADY-13 with PDA medium at a volume ratio of 1:9 and pour plates. The control PDA plate is a normal medium. Inoculate a pathogen bacterial cake in the center of the plate. Set 5 replicates for each treatment. Incubate in the dark at 25 °C in an inverted position. After 5 days, measure the colony diameter of JC by cross measurement and calculate the inhibition rate. Inhibition rate = [control colony diameter - treated colony diameter] / control colony diameter × 100%.

[0047] Using Phytophthora infestans (Pc) and Sclerotium rolfsii (JC) pathogens as indicator bacteria respectively, the plate confrontation method was used to clarify the nutritional and spatial competition of strain ADY-13 against Pc and JC. The results are as Figure 3 shown, Figure 3 in which, A is the control colony of Pc bacteria, B is the colony of Pc bacteria inoculated with ADY-13; C is the control colony of JC bacteria, and d is the colony of JC bacteria inoculated with ADY-13;

[0048] It can be Figure 3 seen that Streptomyces sp. ADY-13 has strong inhibitory effects on both Pc and JC, and the inhibition rates are 41.48% and 88.5% respectively.

[0049] Using Phytophthora infestans (Pc) and Sclerotium rolfsii (JC) pathogens as indicator bacteria respectively, the mycelial growth rate method was used to evaluate the antagonistic effect of a 10-fold dilution of the cell metabolites of Streptomyces sp. ADY-13 on the antagonistic bacteria. The results are as Figure 4 shown;

[0050] Figure 4 in which, E is the control colony of Pc bacteria, F is the colony of Pc bacteria inoculated with the fermentation broth of ADY-13; G is the control colony of JC bacteria, and H is the colony of JC bacteria inoculated with the fermentation broth of ADY-13;

[0051] It can be Figure 4 seen that compared with the colony morphology of normal growth in the control, the inhibition rates of the fermentation products of Streptomyces sp. ADY-13 on Pc and JC are 90.95% and 100% respectively.

[0052] Example 3

[0053] This example is about the effect of the fermentation broth of Streptomyces sp. ADY-13 on the components of konjac tubers;

[0054] 1 Experimental area overview and experimental design

[0055] The experiment was carried out in Zhongtang Community, Xiongshan Sub-district, Weining County, Guizhou Province. The soil in this area is clay soil, and the konjac variety is Amorphophallus konjac. All are second-generation tubers with a size of 200 - 300 g, and the seed amount per mu is about 200 kg. The experiment set 2 different treatments and 3 biological replicates, with about 350 konjac seedlings in each replicate.

[0056] After Streptomyces sp. ADY-13 was activated for 5 days, a 6-mm sterilized pipette tip was used to transfer the bacterial cake to LB liquid medium, and the equipment parameters were set to shake culture at 150 rpm for 7 days. The primary fermentation broth was obtained by filtering with four layers of gauze and diluted 100 times for application. Maintain routine management, and irrigate the Streptomyces sp. ADY-13 fermentation broth (100 times) once at the end of May, 50 mL per plant, and irrigate once every 15 days for a total of 3 times.

[0057] 2 Effects of applying the ADY-13 fermentation broth on the components of konjac tubers:

[0058] 45 days after applying the fermentation broth, dig out the underground tubers of konjac. Randomly select 15 konjac tubers for each treatment. The control group is the konjac tubers without applying the fermentation broth of the candidate biocontrol bacteria. Wash the collected fresh konjac tubers, cut them into slices, put them into a constant temperature air blast drying oven at 45 °C to dry, crush them with a medicine cutter, and sieve through an 80-mesh sieve to obtain konjac powder with more than 90% of the particles passing through the sieve, and then store it in a clean and dry place for later use.

[0059] The determination of color difference color refers to GB / T 7921-2008 Uniform Color Spaces and Color Difference Formulas; the determination of moisture content refers to GB 5009.3-2016 National Food Safety Standard - Determination of Moisture in Foods; weigh more than 0.5 g of konjac powder and dry it at 102 °C; the determination of ash content refers to the national standard GB 5009.4-2016 National Food Safety Standard - Determination of Ash in Foods.

[0060] 2.1 Determination of glucomannan content:

[0061] Determine the glucomannan content in konjac powder according to the operation of NY / T 494-2010. First, add the standard glucose working solution to the volumetric flask according to the gradient, fix the volume, add 3,5-dinitrosalicylic acid for boiling water bath, fix the volume again, zero with distilled water, and measure the absorbance at the wavelength of 550 nm in the microplate reader to draw the glucose standard curve.

[0062] Weigh konjac powder with a balance, add formic acid / sodium hydroxide buffer solution and stir magnetically, fix the volume, centrifuge and take the supernatant, which is the glucomannan extract of konjac powder.

[0063] Absorb the glucomannan extract of konjac powder into a volumetric flask, add 3 mol / L sulfuric acid, mix well, and place it in a sealed boiling water bath for hydrolysis reaction. Add 6 mol / L sodium hydroxide and mix well. The pH value of the solution should reach neutral or near neutral, and make up the volume with distilled water to obtain the konjac powder glucomannan hydrolysis solution.

[0064] Add the konjac powder hydrolysis solution, the extract, and distilled water into three volumetric flasks respectively. Sequentially add 3,5-dinitrosalicylic acid reagent and heat it in a boiling water bath to promote the color reaction. After making up the volume, measure the absorbance at a wavelength of 550 nm, measure the absorbance values of the extract and the hydrolysis solution respectively, draw the corresponding standard curve and calculate the corresponding milligram number of glucose. The calculation formula is as follows:

[0065] The content of glucomannan in konjac powder (%) = (e(5T - To)×50 / m×(1 - W)×1000)×100, where e represents the ratio of the molecular weights of glucose and mannose residues in glucomannan to the molecular weights of glucose and mannose generated after its hydrolysis, and e = 0.9; T represents the milligram number of glucose in the glucomannan hydrolysis solution found on the standard curve, with the unit of milligram (mg); To represents the milligram number of glucose in the glucomannan extract found on the standard curve, with the unit of milligram (mg); m represents the mass of the konjac powder sample, with the unit of milligram (mg); w represents the water content of the sample, with the unit of (%).

[0066] 2.2 Determination of starch content:

[0067] Weigh 0.01 g of konjac powder, operate according to the instructions to obtain the supernatant for standby. Preheat the microplate reader and adjust the temperature of the water bath; dilute the glucose standard solution to obtain standard solutions with different concentration gradients.

[0068] Transfer 50 μL of the standard solution (using distilled water as a control) and 250 μL of the working solution to an EP tube to obtain the preparation test solution of the standard product; then absorb the prepared supernatant, dilute it five times with distilled water, and transfer it to an EP tube with 250 μL of the working solution; put all the EP tubes into a water bath at a preset temperature for 10 min and then cool down, and record the absorbance values A of the standard product and the sample at a wavelength of 620 nm respectively. Draw a standard curve based on the standard product concentration and absorbance, and substitute the A value to calculate the starch content.

[0069] The starch content (mg / g mass) = x×V extraction÷W÷1.11×F = 0.811x÷W×F;

[0070] In the formula: V extraction represents the volume after extraction, with the unit of milliliter (mL);

[0071] W represents the sample mass, with the unit of gram (g);

[0072] F represents the sample dilution factor.

[0073] 2.3 Determination of protein carbonyl content:

[0074] Precisely weigh approximately 0.05 g of konjac powder using a balance, add 1 mL of extraction solution, repeatedly shake and mix the tissue fluid and the extraction solution to form a homogenate, centrifuge, take the supernatant, add Reagent 1, mix well, and let it stand at room temperature. Centrifuge again to obtain the supernatant for standby. Preheat the microplate reader, measure the absorbance A at a wavelength of 370 nm, perform the determination, refer to the instruction manual, and calculate the protein carbonyl content according to the sample mass.

[0075] Protein carbonyl content (μmol / g mass) = (A 370测定管 - A 370对照管 ) ÷ (ε × d) × V ÷ (W × V 样本 ÷ V 提取 ) = (A 370测定管 - A 370对照管 ) ÷ 16 ÷ W

[0076] In the formula: ε represents the extinction coefficient of protein carbonyl, 22 mL / μmol / cm;

[0077] V represents the volume of Reagent 6 added, 0.2 mL;

[0078] V sample represents the volume of sample added, 0.16 mL;

[0079] V extraction represents the volume of extraction solution and Reagent 1 added, 1.1 mL;

[0080] W represents the sample mass, with the unit of (g).

[0081] The measurement results are shown in Table 2;

[0082] Table 2

[0083]

[0084]

[0085] As can be seen from Table 2:

[0086] There were significant differences in the ash content when applying the fermentation broth of biocontrol bacterium ADY-13 (P < 0.05), and no significant differences in color difference, moisture, glucomannan, protein carbonyl, and starch content (P > 0.05). The color differences of konjac with and without applying the fermentation broth of biocontrol bacterium were 73.9633 ± 2.5863a and 73.7633 ± 1.5410a respectively, an increase of 0.27%. The moisture contents of konjac with and without applying the fermentation broth of biocontrol bacterium ADY-13 were 6.95 ± 0.45a and 7.48 ± 0.47a respectively, a decrease of 7.1%. The ash contents of konjac with and without applying the fermentation broth of biocontrol bacterium ADY-13 were 4.55 ± 0.01a and 4.37 ± 0.01b respectively, an increase of 4.1%. The glucomannan contents of konjac with and without applying the fermentation broth of biocontrol bacterium ADY-13 were 31.79 ± 2.33a and 29.21 ± 1.51a respectively, an increase of 8.8%. The protein carbonyl contents of konjac with and without applying the fermentation broth of biocontrol bacterium ADY-13 were 0.0500 ± 0.0223a and 0.0960 ± 0.0078a respectively, a decrease of 48%. The starch contents of konjac with and without applying the fermentation broth of biocontrol bacterium ADY-13 were 221.3 ± 44.6175a and 167 ± 29.0563a respectively, an increase of 32.5%.

[0087] Example 4

[0088] This example is about the effect of the fermentation broth of Streptomyces ADY-13 on the texture of konjac tofu;

[0089] Weigh 8g of ordinary konjac powder and dissolve 1.2g of edible alkali in warm water. Boil water in a pot and pour in the konjac powder. Keep stirring in the pot for 12 - 15 min and then add the alkaline water and mix well. Add water to cover the konjac tofu, bring to a boil over high heat and then turn to low heat and cook for 30 min. Take it out and set aside.

[0090] Use an FTC texture analyzer to measure the TPA of konjac tofu. The diameter of the probe is 75mm, and the parameter settings are as follows: the force sensor is 500N, the probe returns to a height of 25mm above the sample surface, the deformation percentage is 50, the detection speed is 60mm / min, and the starting force is at least 0.15L / C: 1.5N.

[0091] Under the same treatment conditions, conduct texture detection on konjac tofu made from konjac tubers with and without applying the fermentation broth of biocontrol bacterium ADY-13 (CK), and set the same parameters. The results are shown in Table 3;

[0092] Table 3

[0093]

[0094] As can be seen from Table 3, there were no significant differences in the data of adhesiveness, elasticity, and chewiness between konjac tofu made from the fermentation broth of biocontrol bacterium ADY-13 after growth and konjac tofu made without the fermentation broth (P>0.05). However, the data of hardness, gumminess, elasticity, and cohesiveness showed significant differences between the application of the fermentation broth of biocontrol bacterium ADY-13 and without the fermentation broth (P<0.05). It can be concluded that the application of the fermentation broth of biocontrol bacterium ADY-13 will affect the hardness, gumminess, and cohesiveness in the TPA index of konjac tofu, which can be used to distinguish the quality differences of konjac tofu.

[0095] In the texture curve atlas with a detection speed of 60 mm / min (as Figure 5 ) shown, in the figure, A-13 is the texture curve atlas of konjac tofu made from the fermentation broth of biocontrol bacterium ADY-13, and CK is the texture curve atlas of konjac tofu made without the fermentation broth;

[0096] From Figure 5 it can be seen that: during the compression process of konjac tofu made from the fermentation broth of biocontrol bacterium ADY-13, there is only one peak, and only the hardness value is recorded. The curve shows good symmetry, indicating that there is no rupture during compression, and the konjac tofu has good elasticity. The hardness of konjac tofu made without the biocontrol bacterium fermentation broth CK is smaller than that of ADY-13, and the uniformity of the texture curve shown is poor, indicating that the structure and tissue of the konjac tofu are damaged, greatly reducing its recovery performance.

[0097] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A Streptomyces strain antagonistic to plant disease pathogens, characterized in that: The Streptomyces strain antagonizing plant disease pathogens is Streptomyces ADY-13 (Streptoverticillium reticulum ADY-13), which is preserved in the China Center for Type Culture Collection with a preservation number of CCTCCNO: M20241487; the preservation time is July 4, 2024.

2. The Streptomyces strain for antagonizing plant disease pathogens according to claim 1, characterized in that: The plant disease pathogens include potato late blight pathogens and konjac white rot pathogens.

3. A bacterial agent containing the Streptomyces strain antagonistic to plant disease pathogens according to claim 1.

4. Use of the Streptomyces strain antagonistic to plant disease pathogens according to claim 1 in the preparation of a preparation for preventing and treating potato late blight and / or konjac white rot.

5. Use of the fermentation liquid of the Streptomyces strain antagonistic to plant disease pathogens according to claim 1 in the preparation of a preparation for preventing and treating potato late blight and / or konjac white rot, characterized in that: The fermentation liquid is obtained by inoculating the Streptomyces strain antagonistic to plant disease pathogens according to claim 1 into LB liquid culture medium for fermentation and filtration sterilization.

6. A preparation for preventing and treating potato late blight and / or konjac white rot, characterized in that: The preparation comprises the Streptomyces strain antagonistic to plant disease pathogens according to claim 1 and / or the fermentation broth of the Streptomyces strain antagonistic to plant disease pathogens according to claim 1, and the fermentation broth is obtained by inoculating the Streptomyces strain antagonistic to plant disease pathogens according to claim 1 into LB liquid culture medium for fermentation culture and filtration sterilization.

7. A method for preventing and treating potato late blight and / or konjac white rot, characterized in that: The method comprises applying the fermentation liquid of the Streptomyces strain antagonistic to plant disease pathogens according to claim 1 to the roots of potatoes and / or konjac; the fermentation liquid is obtained by inoculating the Streptomyces strain antagonistic to plant disease pathogens according to claim 1 into LB liquid culture medium for fermentation culture and filtering and sterilization.

8. Use of the strain of antagonistic plant disease pathogens according to claim 1 and / or the fermentation liquid of the Streptomyces strain of antagonistic plant disease pathogens according to claim 1 in increasing the content of starch and glucomannan in konjac, characterized in that: The fermentation liquid is obtained by inoculating the Streptomyces strain antagonistic to plant disease pathogens according to claim 1 into LB liquid culture medium for fermentation and filtration sterilization.

9. A method for increasing the content of starch and glucomannan in konjac, characterized in that: The method comprises irrigating the fermentation liquid of the Streptomyces strain antagonistic to plant disease pathogens according to claim 1 onto the roots of konjac; the fermentation liquid is obtained by inoculating the Streptomyces strain antagonistic to plant disease pathogens according to claim 1 into LB liquid culture medium for fermentation culture and filtering for sterilization.

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