Multifunctional pleurotus ostreatus XHMG-3 and application of multifunctional pleurotus ostreatus XHMG-3 in watermelon cultivation

Abstract

The invention discloses a multifunctional Pleuroderma pleuroticola XHMG-3 and application thereof in watermelon cultivation, and belongs to the technical field of agricultural microorganisms, the classification name of the strain is Trichoderma pleuroticola, the strain is preserved in China Center for Type Culture Collection on July 8, 2024, the preservation address is Wuhan University, Wuhan, China, and the preservation number is CCTCC NO: M20241518. The bacterial strain is a multifunctional bacterial strain, has growth promoting functions of siderophore production, nitrogen fixation and protease production, has a broad-spectrum bacteriostasis function, can have a good inhibition effect on muskmelon rhizoctonia solani, cucumber fusarium solani, muskmelon fusarium oxysporum and watermelon fusarium oxysporum, and has salt resistance, alkali resistance and low temperature resistance. The multifunctional strain can effectively improve the germination capacity of watermelon seeds and remarkably improve the growth promoting capacity of watermelon seedlings, and has a good prevention and treatment effect on watermelon fusarium wilt. The invention provides beneficial reference for strain breeding suitable for watermelon growth.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural microorganisms, and particularly relates to a multifunctional Trichoderma pleurotus XHMG-3 and application thereof in watermelon cultivation. Background Art

[0002] Watermelon, belonging to the Cucurbitaceae family, genus Citrullus, is native to Africa. The flesh of watermelon is tender and sweet, and it is rich in mineral salts and vitamins. It is the main summer fruit for cooling down. As a popular summer fruit, watermelon has a large cultivation area. However, due to the lack of experience of some growers in cultivating watermelons in facilities, when watermelons grow poorly or have diseases, the application of large amounts of chemical fertilizers will lead to soil and water pollution and ecological environment deterioration. Therefore, the development and application of biogenic pesticides has become an important goal for protecting the environment and promoting sustainable agricultural development.

[0003] Biological control is to use the interaction between microorganisms and between microorganisms and plants to achieve the inhibitory effect of beneficial microorganisms on harmful microorganisms, and because microorganisms have specificity, the growth rate is slow in an environment that is not suitable for their growth, and it often takes a long time to reach the concentration required for crop growth, so it is very important to select suitable microorganisms. From the existing literature reports, the microorganisms that have growth-promoting or disease-preventing effects on watermelon are reported to have Serratia puchengensis (CN115873750A), Bacillus amyloliquefaciens (CN117987292A), Pantoea pineapple (CN104694422B), and Pseudomonas (CN116849230A). However, there are fewer reports on Trichoderma, and there is no report on Trichoderma that has growth-promoting, disease-preventing, salt-tolerant, alkali-tolerant and low-temperature-tolerant functions at the same time. Therefore, the work of screening Trichoderma with multiple functions is still of great significance. Summary of the invention

[0004] In view of this, the present invention provides a multifunctional Pleurotus ostreatus XHMG-3 and application of the same in watermelon cultivation.

[0005] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0006] The invention provides a multifunctional Trichoderma pleuroticola XHMG-3, which is classified and named as Trichoderma pleuroticola. The strain was deposited in China Center for Type Culture Collection on July 8, 2024, with the deposit address being Wuhan University in Wuhan, China, and the deposit number being CCTCC NO: M20241518. The multifunctional Trichoderma pleuroticola XHMG-3 has the growth-promoting ability of producing siderophores, fixing nitrogen, and producing proteases, has a good inhibitory effect on Rhizoctonia solani of melon, Fusarium solani of cucumber, Fusarium oxysporum of melon, and Fusarium oxysporum of watermelon, and has the ability of salt resistance, alkali resistance, and low temperature resistance.

[0007] The present invention also provides application of the multifunctional Trichoderma XHMG-3 in preventing and controlling crop diseases, wherein the pathogens of the crop diseases are Rhizoctonia solani of melon, Fusarium solani of cucumber, Fusarium oxysporum of melon and Fusarium oxysporum of watermelon.

[0008] The invention also provides application of the multifunctional Trichoderma XHMG-3 in preventing and treating watermelon wilt disease, wherein the pathogen of the watermelon wilt disease is Fusarium oxysporum.

[0009] The present invention also provides application of the multifunctional Trichoderma pleurotus XHMG-3 in promoting germination of watermelon seeds.

[0010] The invention also provides application of the multifunctional Pleurotus ostreatus XHMG-3 in promoting the growth of watermelon seedlings.

[0011] It can be seen from the above technical scheme that the present invention provides a multifunctional Trichoderma pleuroticola XHMG-3 and its application in watermelon cultivation. Compared with the prior art, the multifunctional Trichoderma pleuroticola XHMG-3 has the growth-promoting functions of producing iron carriers, fixing nitrogen, and producing proteases, has a broad-spectrum antibacterial function, can have a good inhibitory effect on melon solani, cucumber solani, melon oxysporum Fusarium, and watermelon oxysporum Fusarium, and has the ability to tolerate salt, alkali, and low temperature. The watermelon seed germination experiment, the watermelon seedling growth promotion experiment, and the watermelon wilt control experiment show that the multifunctional strain can effectively improve the germination ability of watermelon seeds, significantly improve the growth-promoting ability of watermelon seedlings, and has a good control effect on watermelon wilt. The present invention provides a useful reference for the selection and breeding of strains suitable for watermelon growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a colony morphology diagram of the multifunctional Pleurotus ostreatus XHMG-3.

[0013] Figure 2 It is the phylogenetic tree of the multifunctional Pleurotus ostreatus XHMG-3.

[0014] Figure 3 It is a test of the anti-pathogen properties of the multifunctional Trichoderma XHMG-3.

[0015] Figure 4 These are the results of testing the growth-promoting properties of the multifunctional Trichoderma XHMG-3.

[0016] Figure 5 It is the result of salt tolerance of the multifunctional Pleurotus ostreatus XHMG-3.

[0017] Figure 6 It is the alkali resistance result of the multifunctional Pleurotus ostreatus XHMG-3.

[0018] Figure 7 This is a picture of watermelon seed germination after inoculation with strain XHMG-3.

[0019] Figure 8 This is a picture of watermelon seed germination after inoculation with strain XHMG-3 under salt stress.

[0020] Fig. 9 This is a picture of the growth of watermelon seedlings in pots after inoculation with strain XHMG-3.

[0021] Fig.10 This is a graph showing the growth-promoting effect on the roots of watermelon seedlings after inoculation with strain XHMG-3.

[0022] Fig.11 This is a schematic diagram of the control effect on watermelon wilt after inoculation with strain XHMG-3. DETAILED DESCRIPTION

[0023] The technical solutions and technical effects of the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings of the present invention.

[0024] The culture medium used in the embodiments of the present invention is as follows:

[0025] (1) Trichoderma selective medium: glucose: 3.0 g, red Bengal: 0.033 g, agar 20 g, Mg·7H 2 0: 0.2g, KCl: 0.15g, K 2 HPO 4 :0.9g, NH 4 NO 3 :1.0g,H 2 0: 1000mL, penicillin: 0.25g, autoclave at 121℃ for 15 minutes.

[0026] (2) Potato dextrose agar (PDA medium): 6.0 g potato powder, 20.0 g glucose, 20 g agar, autoclave at 121°C for 15 min.

[0027] (3) Ashby's medium: 0.2 g potassium dihydrogen phosphate, 10.0 g mannitol, 0.2 g sodium chloride, 0.1 g calcium sulfate, 5.0 g calcium carbonate, 15.0 g agar, 0.2 g magnesium sulfate, pH 7.0 ± 0.1, 1 L distilled water, autoclaved at 121 °C for 15 min.

[0028] (4) Skim milk culture medium: 10 g skim milk powder, 20 g agar, heat and dissolve in 1 L distilled water, and sterilize at 105°C for 20 min to avoid the formation of flocculent protein.

[0029] (5) CAS detection medium: chrome azuro (CAS) 0.06 g, potassium dihydrogen phosphate 0.04 g, hexadecyltrimethylammonium bromide (HDTMA) 0.07 g, ferric chloride hexahydrate 0.002 g, sodium dihydrogen phosphate dihydrate 0.3 g, disodium hydrogen phosphate dodecahydrate 0.3 g, sodium chloride 0.06 g, ammonium chloride 0.1 g, agar 9 g, pH 6.8 ± 0.1, distilled water 1 L, autoclaved at 116 °C for 30 min.

[0030] (6) Organophosphorus bacterial culture medium: 10.0 g glucose, 0.2 g lecithin, 0.5 g ammonium sulfate, 0.5 g yeast extract powder, 0.3 g potassium chloride, 0.3 g magnesium sulfate, 0.03 g ferrous sulfate, 0.03 g manganese sulfate, 1.0 g calcium carbonate, 0.3 g sodium chloride, 15.0 g agar, pH 7.0-7.5. 1 L distilled water, autoclaved at 121°C for 15 min.

[0031] (7) Chitin medium: 200 mL of chitin colloid, 2.0 g of peptone, 0.5 g of potassium dihydrogen phosphate, 0.3 g of magnesium sulfate, and 20.0 g of agar were dissolved in 1 L of distilled water, pH 7.2, and sterilized by high pressure at 121°C for 15 min.

[0032] Preparation of bacterial solution and pathogen solution: Activate pathogens and Trichoderma in PDA medium, culture at 28°C for 7 days, rinse pathogen spores and Trichoderma spores on the medium with sterile water, filter the bacterial solution with sterilized four-layer gauze to remove hyphae, and dilute the pathogen filtrate with appropriate distilled water to a spore concentration of 1×10 5 Pieces / mL -1 The suspension of Trichoderma filtrate was diluted with appropriate distilled water to a spore concentration of 1×10 7 Pieces / mL -1 The suspension is set aside.

[0033] Example 1. Isolation, identification and preservation of strain XHMG-3

[0034] Soil samples were collected from the rhizosphere of eggplant plants in Minfeng County, Hotan, Xinjiang, using the five-point sampling method. The rhizosphere soil 10-15 cm from the soil surface was collected, sealed in a ziplock bag and brought back to the laboratory, where it was temporarily stored at 4°C for separation. The collected soil samples were isolated from the Trichoderma strains using the dilution plate method. The soil suspension was diluted to 10 -2 , 10 -3 , 10 -4 and 10 -5 , draw 100 μL to Trichoderma selective medium, spread evenly, and culture on the plate at 28°C for 3-4 days. After the plate grows white hyphae, pick the colonies and transfer them to PDA medium for further culture to obtain pure culture. Select the strain that produces green spores after 7 days of culture for morphological and molecular identification.

[0035] See also Figure 1 , under the culture condition of 28℃, the colony grows rapidly on the PDA plate medium. In the early stage of growth, the colony will produce dense and flat cotton-like aerial hyphae, and there are obvious concentric spore-producing areas, which are light yellow at first and then turn into yellow-green. As the culture time increases, the color of the colony turns dark green when it is old, and the conidia are spherical or oval. Based on this feature, this strain can be preliminarily identified as Trichoderma pleurotus.

[0036] Furthermore, the isolated and purified strain XHMG-3 was analyzed by 16S rDNA sequence analysis. The ITS sequence of strain XHMG-3 is as follows: TTCCCGTTAGGGGGTACCTGCGGAGGGATCA. The sequencing results were compared with sequences of the same species but different genera in the NC BI database, and the phylogenetic tree was constructed using MEGA-X software. Figure 2 Based on the results of homology comparison analysis, the gene sequence of strain XHMG-3 was adjacent to that of Trichoderma pleuroticola OP581429.1, and it was identified as Trichoderma pleuroticola and named Trichoderma pleuroticola XHMG-3.

[0037] The strain XHMG-3 was deposited in the China Center for Type Culture Collection on July 8, 2024, with the deposit address being Wuhan University, Wuhan, China, and the deposit number being CCTCC NO:M20241518.

[0038] Example 2, Characteristic Detection of Strain XHMG-3

[0039] (1) Detection of anti-pathogen properties

[0040] The plate confrontation method was used to determine the inhibitory effect of strain XHMG-3 on pathogens such as Rhizoctonia solani of melon, Fusarium solani of cucumber, Fusarium oxysporum of watermelon, and Fusarium oxysporum of melon. Strain XHMG-3 was inoculated on a PDA plate and cultured at 28℃ for 7 days; pathogens were inoculated on a PDA plate and cultured at 28℃ for 7 days. Use a 5mm puncher to punch out the cultured strain XHMG-3 and the edge of the pathogen colony to inoculate on the PDA plate, place them 1 cm away from the edge of the plate, and culture at 28℃. Set up a pathogen control and repeat 3 times. After 7 days of culture, measure the growth radius of the pathogen and the coverage of strain XHMG-3 on the wilt pathogen, and calculate the inhibition rate.

[0041] Inhibition rate (%) = (control wilt pathogen colony radius - confrontation culture wilt pathogen colony radius) ÷ control wilt pathogen colony radius × 100%.

[0042] Table 1: Disease resistance of strain XHMG-3 to soil-borne diseases

[0043]

[0044] Test results such as Figure 3 and as shown in Table 1. The results showed that strain XHMG-3 had a strong inhibitory effect on Fusarium oxysporum of watermelon, Fusarium solani of cucumber, Fusarium oxysporum of melon, and Rhizoctonia solani of melon, with the inhibition rates being 75%, 62%, 75%, and 67%, respectively.

[0045] (2) Growth-promoting properties detection

[0046] The growth-promoting properties of strain XHMG-3 were tested, including the ability to produce iron carriers, solubilize phosphate, fix nitrogen, produce protease, produce chitinase, and produce IAA.

[0047] Nitrogen fixation ability: The strain XHMG-3 was inoculated into the Axubei medium and cultured for 7 days to observe whether there was bacterial growth.

[0048] Phosphorus-dissolving ability: Inoculate strain XHMG-3 on a solid organic phosphate-dissolving medium plate and observe for the appearance of a transparent phosphate-dissolving zone after 7 days of cultivation.

[0049] Iron carrier production: Inoculate strain XHMG-3 onto chrome azure CAS plates and observe after 7 days whether a yellow-green halo appears. If so, record the size of the halo.

[0050] Protease production ability: Inoculate strain XHMG-3 onto skim milk medium plates and observe whether transparent circles appear after 7 days. If so, record the size of the aperture.

[0051] Chitinase production ability: Inoculate strain XHMG-3 onto a chitin culture medium plate and observe whether a transparent circle appears after 7 days. If so, record the size of the aperture.

[0052] IAA detection: 1 mL of the cultured XHMG-3 bacterial liquid was inoculated into the liquid culture medium containing L-tryptophan, and cultured at 28℃ and 200 r / min for 24 h. 100 μL of the bacterial liquid was dripped onto a white ceramic plate, and the same volume of Salkowski colorimetric reagent was added and mixed evenly. The mixture was reacted in the dark at room temperature for 30 min. If the color turns red, it means that the strain has the ability to produce IAA, otherwise it does not.

[0053] Table 2: Results of the growth-promoting properties test of strain XHMG-3

[0054] Siderophore Phosphate Dissolution Nitrogen fixation IAA Chitinase Protease + — + － － +

[0055] Note: The “+” sign indicates that the ability exists, and the “-” sign indicates that the ability does not exist.

[0056] Results Figure 4 and Table 2 , strain XHMG-3 has the ability to fix nitrogen, produce siderophores, and produce proteases.

[0057] (3) Salt resistance, alkali resistance, low temperature resistance and high temperature resistance test

[0058] Taking 1mol / L NaCl as the salt tolerance threshold concentration, the strain XHMG-3 was grown under the threshold concentration. The standard of strain XHMG-3's resistance to salt stress was determined as follows: low salt tolerance: after culturing at 28°C for 4 days, the colony diameter was 50% or less (<4cm) of the control, recorded as "+"; medium salt tolerance: after culturing at 28°C for 4 days, the colony diameter was 50-70% (4-5.5cm) of the control diameter, recorded as "++"; high salt tolerance: after culturing at 28°C for 4 days, the colony diameter was greater than 70% (>5.5cm) of the control diameter, recorded as "+++".

[0059] Taking pH=8.5 as the threshold concentration of alkali resistance, according to the growth of strain XHMG-3 under the threshold pH, the standard of alkali stress resistance of strain XHMG-3 was determined: low alkali resistance: after culturing at 28°C for 4 days, the colony diameter was 50% or less of the control (<4 cm), recorded as "+"; medium alkali resistance: after culturing at 28°C for 4 days, the colony diameter was 50-70% of the control diameter (4-5.5 cm), recorded as "++"; high alkali resistance: after culturing at 28°C for 4 days, the colony diameter was greater than 70% of the control diameter (>5.5 cm), recorded as "+++".

[0060] Taking 14°C as the threshold temperature, the standard of Trichoderma stress temperature resistance was determined according to the growth of Trichoderma at the threshold temperature: low tolerance: after culturing at 14°C for 4 days, the colony diameter was 50% or less of the control (<4 cm), recorded as "+"; medium low temperature resistance: after culturing at 14°C for 4 days, the colony diameter was 50-70% of the control diameter (4-5.5 cm), recorded as "++"; high low temperature resistance: after culturing at 14°C for 4 days, the colony diameter was greater than 70% of the control diameter (>5.5 cm), recorded as "+++".

[0061] Taking 36°C as the threshold temperature, the standard of Trichoderma stress temperature resistance was determined according to the growth of Trichoderma at the threshold temperature: low tolerance: after 4 days of cultivation at 36°C, the colony diameter is 50% or less of the control (<4cm), recorded as "+"; medium high temperature resistance: after 4 days of cultivation at 36°C, the colony diameter is 50-70% of the control diameter (4-5.5cm), recorded as "++"; high high temperature resistance: after 4 days of cultivation at 36°C, the colony diameter is greater than 70% of the control diameter (>5.5cm), recorded as "+++".

[0062] Table 3: Test results of salt resistance, alkali resistance, low temperature resistance and high temperature resistance of strain XHMG-3

[0063] Salt tolerance Alkali resistance Low temperature resistance High temperature resistance +++ ++ ++ －

[0064] See Table 3. Figure 5-6 , strain XHMG-3 is resistant to salt, alkali and low temperature.

[0065] Example 3: Detection of the germination effect of strain XHMG-3 on watermelon seeds

[0066] The strain XHMG-3 was subjected to a seed germination test. The seeds were sterilized with 75% alcohol for 30 seconds, washed with sterile distilled water for 3 times, soaked in 3% sodium hypochlorite for 8-10 minutes, and washed with sterile distilled water for 3-4 times. After soaking the seeds in 55°C warm water, they were soaked in clean water for 3 hours. The seeds of the experimental group were placed in 10 3 cfu / mL, 10 5 cfu / mL, 10 7 cfu / mL three different concentrations of strain XHMG-3 spore suspension for 5h, the control group was soaked in pure water, and 20 watermelon seeds were taken for each treatment, repeated three times. Evenly placed in a sterile culture dish with sterilized double-layer filter paper, and an appropriate volume of pure water was added every day. Then the seeds were placed in a (25±1)℃ constant temperature incubator, and the germination of the seeds was observed and recorded. The germination potential was calculated on the 3rd day, the germination rate was calculated on the 5th day, and the germination index and vitality index were calculated. After the germination on the 5th day, 20 cucumber seedlings were randomly selected from each treatment, the radicle length and hypocotyl length were measured, and the dry and fresh mass was weighed.

[0067] Germination rate (GR) = (N5 / T) × 100%, germination potential (GE) = (N3 / T) × 100%, seedling vigor index (VI) = (average radicle length + average hypocotyl length) × germination rate. Where: N3 is the number of seeds germinated on the 3rd day; N5 is the number of seeds germinated on the 5th day; N is the total number of seeds tested; Gt is the number of germinations within t time; Dt is the corresponding number of germination days. S is the average fresh weight of seedlings.

[0068] Table 4: Effect of strain XHMG-3 on the growth promotion of radicle and hypocotyl of watermelon seeds

[0069]

[0070] Table 5: Effect of strain XHMG-3 on germination of watermelon seeds

[0071]

[0072] See Table 4-5 and Figure 7 It can be seen that the concentration of watermelon seeds inoculated with Trichoderma strain XHMG-3 was 10 3 cfu / mL had the best effect, and the radicle, hypocotyl, germination rate, germination potential and vitality index increased by 14.81%, 43.56%, 21.05%, 16.67% and 50.90% respectively.

[0073] Furthermore, the seeds were sterilized with 75% alcohol for 30 seconds, washed with sterile distilled water for 3 times, soaked in 3% sodium hypochlorite for 8-10 minutes, and washed with sterile distilled water for 3-4 times. After soaking the seeds in 55°C warm water, they were soaked in clean water for 3 hours. 3 The seeds were soaked in a suspension of Trichoderma spores with a concentration of cfu / mL for 5 hours, and the control group was soaked in pure water. Twenty watermelon seeds were taken for each treatment, and repeated three times. After soaking, the seeds were evenly placed in a sterile culture dish with sterilized filter paper, 15mL100mmol / LNaCl was added, and then the seeds were placed in a (25±1)℃ constant temperature incubator. After that, an appropriate volume of 100mmol / L NaCl was supplemented every day. The germination of the seeds was observed and recorded. The germination potential was calculated on the 4th day, the germination rate was calculated on the 6th day, and the germination rate, germination potential and vitality index were calculated. After the germination on the 6th day, 20 watermelon seedlings were randomly selected from each treatment to measure the radicle length, hypocotyl length and number of lateral roots.

[0074] Germination rate (GR) = (N6 / T) × 100%, germination potential (GE) = (N4 / T) × 100%, seedling vigor index (VI) = (average radicle length + average hypocotyl length) × germination rate. Where: N4 is the number of seeds germinated on the 4th day; N6 is the number of seeds germinated on the 6th day; N is the total number of seeds tested.

[0075] Table 6: Growth-promoting effect of strain XHMG-3 on radicle, hypocotyl and lateral root of watermelon seeds under salt stress

[0076]

[0077] Table 7: Effect of strain XHMG-3 on watermelon seed germination under salt stress

[0078]

[0079] See Table 6-7 and Figure 8 It can be seen that under salt stress, the concentration of inoculated strain XHMG-3 was 1×10 3 cfu / mL of spore suspension, the number of radicle, hypocotyl, lateral root and vitality index increased by 41.69%, 18.01%, 70%, 3.7% and 39.12%, respectively.

[0080] Example 4: Detection of the growth-promoting effect of strain XHMG-3 on watermelon seedlings

[0081] The pot experiment was conducted at the National University Science and Technology Park of Ningxia University in Yinchuan, China in October 2023. The test variety was 'Jincheng No. 5' watermelon, purchased from Ningxia Tianyuan Seed Co., Ltd.

[0082] The Jincheng No. 5 watermelon seedlings with two leaves and one heart were inoculated with 15 mL of the spore suspension of strain XHMG-3 (10 7 cfu / mL) root irrigation treatment, each watermelon seedling was irrigated with 15 mL of watermelon root, 15 seedlings were inoculated in each treatment, and it was repeated 3 times. CK was inoculated with only water. The plant height, stem diameter, chlorophyll, leaf area, aboveground fresh weight, aboveground dry weight, underground fresh weight and underground dry weight of the watermelon seedlings were observed and recorded 10 days after inoculation with Trichoderma.

[0083] Table 8: Growth-promoting effect of strain XHMG-3 on watermelon seedlings

[0084]

[0085] See Table 8 and Fig. 9 The inoculation of strain XHMG-3 significantly promoted the increase of plant height, stem diameter, chlorophyll, leaf area, aboveground fresh weight, aboveground dry weight, underground fresh weight and underground dry weight of watermelon seedlings, which increased by 12.22%, 9.18%, 4.53%, 27.34%, 27.75%, 13.75%, 100.63% and 85.82%, respectively.

[0086] See also Fig.10 The inoculation of strain XHMG-3 significantly promoted the increase of total root length, root surface area and root volume of watermelon seedlings by 24.57%, 45.17% and 41.12%, respectively.

[0087] Example 5: Control effect of strain XHMG-3 on watermelon wilt

[0088] The Jincheng No. 5 watermelon seedlings with two leaves and one heart were inoculated with 15 mL of the spore suspension of strain XHMG-3 (10 7 cfu / mL) was used for root irrigation, and 48 h later, the root wound inoculation method was used to inoculate the pathogenic bacteria suspension of Fusarium oxysporum (10 5 cfu / mL), 5 mL of watermelon wilt was irrigated into the roots of each watermelon seedling, and the disease occurrence was investigated according to the disease grading standard for watermelon wilt; CK was inoculated with pathogens only, 15 seedlings were inoculated in each treatment, and the treatment was repeated 3 times. 20 days after inoculation with pathogens, the incidence of watermelon wilt was observed and recorded, and the disease index was calculated.

[0089] The calculation method of disease index and control effect of strains is as follows:

[0090] Disease index = ∑ (number of plants at each disease level × representative value of each level) / (total number of plants surveyed × representative value of the highest level) × 100; Control effect = (disease index after control × disease index of control area before control) / (disease index before control × disease index of control area after control) × 100;

[0091] Level 0: healthy plants, growing well and without disease symptoms;

[0092] Level 1: The leaves of the plant gradually wilt from bottom to top, as if lacking water, and the symptoms can be recovered;

[0093] Level 2: The leaves of the plant wilt from bottom to top and cannot return to normal;

[0094] Level 3: The leaves of the whole plant wither and droop and cannot return to normal;

[0095] Level 4: The leaves dry up and the whole plant dies.

[0096] Table 9: Control effect of strain XHMG-3 on watermelon wilt

[0097] deal with Disease index Disease prevention effect (%) CK 73.33 - XHMG-3 26.67 63.63

[0098] See Table 9 and Fig.11 ,The results showed that the disease index of watermelon plants treated with strain XHMG-3 for watermelon wilt was 26.67, and the prevention and control effect was 63.63%.

[0099] What is disclosed above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A multifunctional Trichoderma sp. XHMG-3, characterized in that: Its classification is named Trichoderma pleuroticola The strain was deposited in the China Type Culture Collection on July 8, 2024, with the deposit address being Wuhan University, Wuhan, China, and the deposit number being CCTCC NO:M20241518; the multifunctional Pleurotus ostreatus XHMG-3 has the growth-promoting ability of producing iron carriers, fixing nitrogen, and producing proteases, and has a good inhibitory effect on Rhizoctonia solani of melon, Fusarium solani of cucumber, Fusarium oxysporum of melon, and Fusarium oxysporum of watermelon, and has the ability to withstand salt, alkali, and low temperatures.

2. The use of the multifunctional Trichoderma XHMG-3 according to claim 1 in preventing and controlling crop diseases, characterized in that: The pathogenic bacteria of the crop diseases are Rhizoctonia solani of melon, Fusarium solani of cucumber, Fusarium oxysporum of melon and Fusarium oxysporum of watermelon.

3. The use of the multifunctional Trichoderma XHMG-3 according to claim 1 in preventing and treating watermelon wilt disease, characterized in that: The pathogen of watermelon wilt disease is Fusarium oxysporum.

4. Use of the multifunctional Trichoderma XHMG-3 as claimed in claim 1 in promoting the germination of watermelon seeds.

5. Use of the multifunctional Pleurotus ostreatus XHMG-3 as claimed in claim 1 in promoting the growth of watermelon seedlings.

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