Pleurotus ostreatus growth promoting bacterium, screening method and application of pleurotus ostreatus growth promoting bacterium

Abstract

The invention belongs to the technical field of microorganisms, and particularly relates to an oyster mushroom growth-promoting bacterium, a screening method and application of the oyster mushroom growth-promoting bacterium. The strain comes from a microbial library of an oyster mushroom substrate, and growth of oyster mushroom hyphae can be remarkably promoted by adding the strain and a strain filtrate into a solid culture medium and the oyster mushroom substrate; the combination effect of a volatile compound 2-butanone-acetone-styrene generated by the strain also has the characteristic of promoting the growth of oyster mushroom mycelia, a new way is found for artificial cultivation of oyster mushrooms and a micro-ecological control technology, and a foundation is laid for improving economic and social benefits of edible mushroom production.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and in particular relates to a growth-promoting bacterium of Pleurotus ostreatus, a screening method and an application thereof. Background Art

[0002] Pleurotus ostreatus (scientific name: Pleurotus ostreatus) is a fungus of the genus Pleurotus in the family Pleurotaceae. The fruiting bodies grow in clusters or overlapping, and the caps grow in clusters in the shape of tiles, fans, shells, or irregular funnels. Pleurotus ostreatus is an edible fungus that contains rich nutrients and has the effects of dispelling wind and cold, relaxing muscles and activating blood circulation. It can also be used to treat symptoms such as back and leg pain, numbness of hands and feet, and blocked tendons and blood circulation. It has certain benefits in preventing cancer, regulating women's menopausal syndrome, improving human metabolism, and strengthening physical fitness.

[0003] Oyster mushrooms are light-loving fungi, mostly growing on dead wood, rotten stumps or dead parts of living trees of broad-leaved species. Oyster mushrooms are distributed all over the world and are cultivated artificially in most parts of China, especially in Henan, Hebei, Shandong, Heilongjiang and other provinces. The growth cycle of artificially cultivated oyster mushrooms is about 4-5 months. It takes about 30-35 days from inoculation to mature mycelium. During this period, growers need to invest a long time in maintenance, wasting a lot of manpower, financial resources and material resources. Therefore, it is necessary to find a method to effectively shorten the mycelium growth time.

[0004] In the ecological microsystem of Pleurotus ostreatus, in addition to abiotic factors such as soil, temperature, and humidity, some biotic factors such as plants, fungi, and bacteria form a delicate harmonious community, which are mutually beneficial and grow together. Studies have shown that rhizosphere microorganisms under natural conditions may have a certain promoting effect on the fruiting body formation of large fungi. Its mechanism of action includes improving the nutrient absorption of wild fungi, competing with pathogens for ecological niches, improving the resistance of wild fungi, and promoting spore germination and mycelial growth. At the same time, when the mushroom mycelium grows through the pretreated substrate, after the bacteria colonize in the mycelium, they can mobilize nutrients in the environment for mycelium absorption and stimulate mycelial growth by removing growth inhibitors.

[0005] The present invention collects the matrix after harvesting a batch of oyster mushrooms, separates the microorganisms in the matrix, starts screening of growth-promoting bacteria in the laboratory, and identifies the screened bacteria by combining morphology and genomic DNA amplicon sequencing. Through the application of co-cultivation of growth-promoting bacteria and oyster mushrooms in the laboratory, a new way is found for artificial cultivation of oyster mushrooms and microecological control technology, laying a foundation for improving the economic and social benefits of edible fungus production. Summary of the invention

[0006] In order to solve the problem that the mycelium extension growth time is long during the cultivation of oyster mushrooms, resulting in high production costs, the present invention uses an in-situ screening method to screen oyster mushroom growth-promoting bacteria A12 from microorganisms separated from oyster mushroom substrates, and identifies it as Hunan Pseudomonas (Pseudomonashunanensis). The bacteria comes from the microbial library of the oyster mushroom substrate itself, ensuring the safety of application in edible mushroom cultivation.

[0007] To achieve the above objectives, the present invention provides the following technical solutions:

[0008] Technical solution 1:

[0009] The invention provides a growth-promoting bacterium for Pseudomonas hunanensis A12, which is deposited in China Center for Type Culture Collection, with the deposit address at Luojia Mountain, Bayi Road, Wuchang District, Wuhan City, Hubei Province, and the deposit number is CCTCC M 20242598.

[0010] As a further technical solution, the 16S rRNA gene sequence of the Hunan Pseudomonas A12 is shown as SEQ ID NO: 1.

[0011] Technical solution 2:

[0012] A method for screening the above-mentioned Pleurotus ostreatus growth-promoting bacteria comprises the following steps:

[0013] S1. Activation of Pleurotus ostreatus: PDA solid culture medium was used, and the mycelium blocks of Pleurotus ostreatus were inoculated on the PDA solid culture medium, and cultured in the dark at a constant temperature of 28°C;

[0014] S2. Collection of substrate for oyster mushroom: Collect oyster mushroom bags, remove the mushroom skin, collect substrates with a depth of 2 cm and 10 cm, form a mixed sample, place it in a sealed bag, and keep it fresh at 4°C for 24 hours;

[0015] S3. Isolation of dominant bacteria: Take the matrix sample treated in step S2, put it into a conical bottle with sterile water, dilute it, spread the dilution on an LB plate, incubate it upside down at 37°C, inoculate bacteria of different morphologies on a new LB plate for streak separation until the bacterial morphology is completely consistent, and store the purified bacteria on a slant at 4°C to obtain the dominant bacteria.

[0016] Technical solution three:

[0017] A use of the above-mentioned Pleurotus ostreatus growth-promoting bacteria or the Pleurotus ostreatus growth-promoting bacteria obtained by the above-mentioned screening method in promoting the growth of Pleurotus ostreatus.

[0018] Technical solution 4:

[0019] A pleurotus ostreatus growth-promoting bacteria liquid comprising the pleurotus ostreatus growth-promoting bacteria mentioned above or the pleurotus ostreatus growth-promoting bacteria obtained by the above screening method.

[0020] Technical solution five:

[0021] A method for preparing the above-mentioned mushroom growth-promoting bacterial liquid comprises the following steps:

[0022] Step 1, inoculate the growth-promoting bacteria of Pleurotus ostreatus into the liquid LB culture medium, and the culture conditions are: temperature 37°C, rotation speed 200r / min, and shaker culture for 12h;

[0023] Step 2: The number of viable bacteria of Hunan Pseudomonas A12 is ≥ 10 7 CFU / mL, and then the supernatant was collected after centrifugation;

[0024] Step 3: Filter the supernatant through a 0.22 μm sterile filter to obtain a Pleurotus ostreatus growth-promoting bacterial liquid.

[0025] Technical solution six:

[0026] An application of the above-mentioned Pleurotus ostreatus growth-promoting bacterial liquid in promoting the growth of Pleurotus ostreatus.

[0027] Beneficial effects:

[0028] 1. The present invention provides a growth-promoting bacterium for Pleurotus ostreatus and a screening method. The bacterium is selected from the microbial library of the Pleurotus ostreatus matrix itself, has a significant effect on promoting the growth of Pleurotus ostreatus mycelium, and is safe and efficient.

[0029] 2. The present invention provides an application of a Pleurotus ostreatus growth-promoting bacterium and its volatile compounds in increasing the growth rate of Pleurotus ostreatus mycelium. It also provides a method for preparing a Pleurotus ostreatus growth-promoting bacterial liquid and its application in increasing the growth rate of Pleurotus ostreatus mycelium, laying a foundation for effectively shortening the mycelium growth time in artificial cultivation of Pleurotus ostreatus. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a comparison diagram of the confrontation between the growth-promoting bacteria of Pleurotus ostreatus and the Pleurotus ostreatus plate in the present invention. The legend: a is a control reference of Pleurotus ostreatus, and b is a confrontation culture of Pleurotus ostreatus and the growth-promoting bacteria of Pleurotus ostreatus.

[0031] Figure 2 It is a comparison diagram of the co-culture of Pleurotus ostreatus growth-promoting bacteria and Pleurotus ostreatus in two compartments in the present invention, with legend: a is a control reference of Pleurotus ostreatus, and b is a co-culture of Pleurotus ostreatus and Pleurotus ostreatus growth-promoting bacteria in two compartments.

[0032] Figure 3 This is a comparison diagram of the co-culture of the gas compound 2-butanone-acetone-styrene produced by the growth-promoting bacteria of Pleurotus ostreatus and Pleurotus ostreatus in two compartments. Note: a is the control reference of Pleurotus ostreatus, and b is the co-culture of Pleurotus ostreatus and the gas compound in two compartments.

[0033] Figure 4 This is a comparison chart of the growth of Pleurotus ostreatus mycelium after adding the Pleurotus ostreatus growth-promoting bacteria liquid of the present invention to the Pleurotus ostreatus substrate for 7 days. Note: a is a control reference, and b is when 7% Pleurotus ostreatus growth-promoting bacteria is added. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and beneficial effects of the present invention more clear, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings to facilitate understanding by technicians.

[0035] In the embodiment of the present invention, a mushroom growth-promoting bacterium is Hunan Pseudomonas A12

[0036] (Pseudomonas hunanensis A12), deposited in China Center for Type Culture Collection, deposit address: Luojia Mountain, Bayi Road, Wuchang District, Wuhan City, Hubei Province, bacteria deposit number: CCTCC M20242598, named: Pseudomonas hunanensis A12.

[0037] The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0038] Example 1: Isolation, screening and identification of dominant bacteria

[0039] Step I: Isolation of dominant bacteria, comprising the following steps:

[0040] 1. Activation of Oyster Mushroom

[0041] Use PDA solid culture medium, formula: potato 200.0g / L, glucose 20.0g / L, agar 18g / L, pH 6.0, on a sterile operating table, take a 1cm thick plate of Pleurotus ostreatus mycelium. 2 Mycelial blocks of different sizes were inoculated on PDA solid culture medium and cultured in the dark at a constant temperature of 28°C.

[0042] 2. Collection of Pleurotus ostreatus substrate

[0043] Select the mushroom bags after harvesting a batch of oyster mushrooms, remove the oyster mushroom skin on the surface of the mushroom bags, collect the matrix at a depth of about 2 cm and 10 cm, make a mixed sample of 10 g, put it in a sampling seal bag, keep the sample at 4°C, and carry out subsequent processing within 24 hours.

[0044] 3. Isolation of symbiotic dominant bacteria of Pleurotus ostreatus

[0045] Take 10g of the bacterial bag matrix sample and put it into a 250mL conical flask containing 90mL of sterile water. Oscillate at 37℃ and 200rpm for 20min and then let it stand for 10min. Take 100μL of the supernatant and put it into a 2mL sterile centrifuge tube containing 900μL of sterile water. Shake well to obtain 10 -2 Dilution. Take 10 -4 , 10 -5100 μL of each dilution solution was spread on LB plates and inverted at 37°C for culture. Different forms of bacteria were inoculated into new LB plates for streaking separation until the bacterial morphology was completely consistent. The purified bacteria were stored on slant plates at 4°C.

[0046] Results: This experiment separated the dominant bacteria from the collected Pleurotus ostreatus spawn matrix, and screened out the target bacteria through purification and preliminary morphological identification, providing stable experimental materials for the screening research of growth-promoting bacteria in the laboratory.

[0047] Step II Screening and identification of growth-promoting bacteria, including the following steps:

[0048] 1. Plate confrontation test between dominant bacteria and Pleurotus ostreatus mycelium

[0049] PDA culture medium was used to carry out growth promotion test on the dominant bacteria isolated from the oyster mushroom bag in step Ⅰ and oyster mushroom by plate confrontation culture, and the growth-promoting bacteria of oyster mushroom mycelium were screened. The well-growing oyster mushroom mycelium blocks were inoculated into PDA culture medium and cultured in a constant temperature incubator at 28℃ for 10 days. The oyster mushroom plates with consistent growth were inoculated on one side of the PDA culture medium. The dominant bacteria activated for 24 hours were inoculated at 4 cm away from the oyster mushroom mycelium block in the treatment group, and the control group without bacteria was used as a reference, and repeated 4 times. The culture was continued at a constant temperature of 28℃, and the growth radius of oyster mushroom mycelium was measured every day. The measurement was continued for 5 consecutive days to obtain the average daily growth rate (mm / d) of oyster mushroom mycelium, and the growth rate was calculated to determine the effect of the dominant bacteria on the growth of oyster mushroom mycelium.

[0050] Calculation formula:

[0051] Growth rate % = [(treatment mycelium growth rate - control mycelium growth rate) / control mycelium growth rate] × 100

[0052] The results of the confrontation between the dominant bacteria in the fungus bag and the oyster mushroom are shown in Figure 1 And Table 1.

[0053] Table 1 Effects of dominant bacteria in the fungus bag on the growth of Pleurotus ostreatus mycelium

[0054]

[0055] Table 1 shows the effect of the dominant bacteria separated from the oyster mushroom bag in step I on the growth of oyster mushroom mycelium. The oyster mushroom growth-promoting bacteria promote the growth rate of oyster mushroom mycelium to 3 mm / d, and the growth-promoting effect (growth rate) reaches 30.4% compared with the growth rate of the control reference of 2.3 mm / d;

[0056] Figure 1 The experiment of confrontation between Pleurotus ostreatus growth-promoting bacteria and Pleurotus ostreatus plates was demonstrated. It can be clearly seen from the cultivation conditions of Pleurotus ostreatus growth-promoting bacteria on the Pleurotus ostreatus mycelium plates that the Pleurotus ostreatus growth-promoting bacteria isolated from the Pleurotus ostreatus spawn bags showed the effect of promoting the growth of Pleurotus ostreatus mycelium.

[0057] 2. Identification of growth-promoting bacteria species

[0058] The Pleurotus ostreatus growth-promoting bacteria screened from the Pleurotus ostreatus bacteria bag were cultured on plates for molecular biological identification: the Pleurotus ostreatus growth-promoting bacteria were purified, and the genomic DNA was extracted according to the method of the bacterial genomic DNA extraction kit, and PCR amplification was performed using the 16S universal primer.

[0059] Table 2 16S PCR amplification system

[0060]

[0061] The amplified sequences were sequenced by gel recovery, and the similarity of the 16S rRNA gene sequences of the bacteria was compared in the database. Bacteria with a similarity higher than 98.65% were considered to be of the same genus. The results showed that the growth-promoting bacteria of Pseudomonas hunanensis isolated from the Pseudomonas pleurotus ostreatus bag in this study were identified as Pseudomonas genus, with the taxonomic name: Hunan Pseudomonas Pseudomonas shunanensis, which was submitted to the Microbial Culture Collection Center for preservation on November 20, 2024, with the number CCTCC M 20242598, and named: Pseudomonas hunanensis A12.

[0062] Example 2: Application of Pleurotus ostreatus growth-promoting bacteria to promote the growth of Pleurotus ostreatus mycelium

[0063] A two-compartment culture dish with a partition in the middle was used, solid LB culture medium was added to one compartment, and PDA solid culture medium was added to the other compartment, and they were set aside after cooling and solidification.

[0064] The growth-promoting bacteria of Pseudomonas ostreatus were cultured in liquid test tubes using conventional LB medium at a temperature of 37°C and a rotation speed of 200 r / min. The culture was carried out for 10 h until the number of viable bacteria of Pseudomonas hunanensis A12 was ≥10 7 After the CFU / mL was reached, 10 μL of the growth-promoting bacteria solution of Pleurotus ostreatus was streaked onto the solid LB medium in a two-grid culture dish and placed in a 37°C incubator for 48 h. The dish with LB added was used as the control, and each treatment was repeated 4 times.

[0065] After the growth-promoting bacteria of Pleurotus ostreatus fully grew out in the two-grid culture dish, the Pleurotus ostreatus mycelium blocks with basically the same growth status were inoculated into the PDA culture medium of the two-grid culture dish and placed in a constant temperature incubator at 28°C for dark culture. The growth radius of the Pleurotus ostreatus mycelium was measured every day for 5 consecutive days to obtain the average daily growth rate (mm / d) of the Pleurotus ostreatus mycelium, and the growth rate was calculated to determine the effect of the growth-promoting bacteria of Pleurotus ostreatus on the growth of the Pleurotus ostreatus mycelium.

[0066] The results of promoting the growth of Pleurotus ostreatus by Pleurotus ostreatus mycelium are shown in Figure 2 And Table 3.

[0067] Table 3 Effects of Pleurotus ostreatus growth-promoting bacteria on the mycelial growth of Pleurotus ostreatus.

[0068]

[0069] Table 3 compares the effects of streaking Pleurotus ostreatus growth-promoting bacteria in a two-grid culture dish on the growth of Pleurotus ostreatus mycelium. Compared with the control reference, the gas produced by Pleurotus ostreatus growth-promoting bacteria promoted the growth of Pleurotus ostreatus mycelium at a rate of 6 mm / d, significantly promoting the growth of Pleurotus ostreatus mycelium, and its growth rate reached 71.4%.

[0070] Figure 2 The experiment of two-grid co-cultivation in which the gas produced by Pleurotus ostreatus growth-promoting bacteria acts on Pleurotus ostreatus mycelium was demonstrated. It can be clearly seen from the cultivation conditions of Pleurotus ostreatus mycelium on the two-grid plate that the gas produced by A12 bacteria showed the effect of promoting the growth of Pleurotus ostreatus mycelium.

[0071] Example 3: Application of Compounds in Gas Produced by Pleurotus ostreatus Growth-Promoting Bacteria A12 to Promote the Growth of Pleurotus ostreatus Mycelium

[0072] A two-compartment culture dish with a partition in the middle was used. Solid PDA culture medium was added to one compartment and 25 mm 2 Filter paper pieces of about the same size will be kept for later use after the culture medium solidifies.

[0073] GC-MS detected that the gas produced by Pleurotus ostreatus growth-promoting bacteria A12 contained 2-butanone, acetone and styrene. After diluting the three substances with methanol to 1μmoL / L, 1nmoL / L and 100nmoL / L respectively, 20μL of each was added to the filter paper in the two-grid culture dish so that it could remain volatile. An equal amount of methanol was added to the control. At the same time, the Pleurotus ostreatus mycelium block was inoculated into PDA culture medium and placed in a constant temperature incubator at 28℃ for dark culture. The growth radius of Pleurotus ostreatus mycelium was measured every day for 5 consecutive days, and the growth rate was calculated to determine the influence of the dominant bacteria on the growth of Pleurotus ostreatus mycelium.

[0074] The compounds in the gas produced by the growth-promoting bacteria of Pleurotus ostreatus promote the growth of mycelium of Pleurotus ostreatus. Figure 3 And Table 4.

[0075] Table 4 Effects of compounds in the gas of Pleurotus ostreatus growth-promoting bacteria on the growth of Pleurotus ostreatus mycelium

[0076]

[0077] Table 4 compares the effects of volatile compounds 2-butanone-acetone-styrene produced by Pleurotus ostreatus growth-promoting bacteria on the mycelial growth of Pleurotus ostreatus in a two-compartment culture dish. Compared with the control reference, the combination of the three substances has a mycelial growth promotion rate of 30.8% for Pleurotus ostreatus.

[0078] Figure 3The bisection co-cultivation experiment of 2-butanone-acetone-styrene on Pleurotus ostreatus mycelium was demonstrated. It was clear from the cultivation conditions of Pleurotus ostreatus mycelium on the bisection plates that the combination of the three substances showed the effect of promoting the growth of Pleurotus ostreatus mycelium.

[0079] Example 4: Preparation and application of a mushroom growth-promoting bacterial liquid

[0080] 1. A method for preparing a mushroom growth-promoting bacterial liquid comprises the following steps:

[0081] S1. Inoculate the growth-promoting bacteria A12 of Pleurotus ostreatus into the liquid LB culture medium. The culture conditions are: temperature 37°C, rotation speed 200r / min, and shaker culture for 12h.

[0082] S2, Pseudomonas A12 viable count ≥ 10 7 CFU / mL, centrifuge at 5000rpm for 15min to obtain the supernatant.

[0083] S3. Filter the supernatant through a 0.22 μm sterile filter to obtain a growth-promoting bacterial solution.

[0084] 2. Application of Pleurotus ostreatus growth-promoting bacterial liquid in solid culture medium

[0085] After sterilizing the PDA solid medium at 115°C for 30 minutes, the growth-promoting bacteria filtrate was added to the PDA at a ratio of 3%, 5%, 7%, and 9% before it cooled and solidified, and the same ratio of liquid LB was added to the PDA solid medium as a control reference. After the medium solidified, the oyster mushroom mycelium block was inoculated and cultured in a dark incubator at 28°C. After 5 days, the growth radius of the oyster mushroom mycelium was measured and the growth of the oyster mushroom mycelium was compared and analyzed.

[0086] The results of promoting the growth of Pleurotus ostreatus mycelium by Pleurotus ostreatus growth-promoting bacteria in solid culture medium are shown in Table 5.

[0087] Table 5 Effects of Pleurotus ostreatus growth-promoting bacterial solution on the mycelial growth of Pleurotus ostreatus in solid culture medium

[0088]

[0089]

[0090] The results in Table 5 show that the bacterial solution has no effect on the growth of mycelium when the addition ratio is low. It has a certain effect on the growth of mycelium in the concentration range of 5-9%. When the addition ratio is 9%, the growth rate of mycelium of Pleurotus ostreatus shows a downward trend. When the bacterial filtrate is added at a concentration level of 7%, the mycelium radius of Pleurotus ostreatus is 23.8mm and the growth rate is 30.10%. The results show that the bacterial solution can promote the growth of mycelium of Pleurotus ostreatus, which is manifested in the best effect of promoting the mycelium growth of Pleurotus ostreatus when the bacterial filtrate is added to the PDA medium at a ratio of 7%.

[0091] 3. Application of Pleurotus ostreatus growth-promoting bacteria liquid on Pleurotus ostreatus substrate

[0092] After the corn cob is pre-wetted, the oyster mushroom matrix is ​​prepared according to the formula of adding various auxiliary materials of the oyster mushroom matrix (corn cob: 72% bran: 25% lime: 2% calcium carbonate: 1%, 121°C, 40min high pressure sterilization). After sterilization, 20g of the matrix per tube is divided into test tubes and sterilized again in the sterilizer.

[0093] The growth-promoting bacterial liquid was added to the cultivation material of Pleurotus ostreatus at a ratio of 3% to 9%, and the LB was used as the control. Each group of treatments was repeated 4 times. After the Pleurotus ostreatus mycelium block was inoculated into the test tube, it was cultured in the dark in an incubator at about 28°C. After 7 days, the average daily growth rate (mm / d) of the Pleurotus ostreatus mycelium was obtained, and the growth rate was calculated to determine the effect of the growth-promoting bacterial liquid on the growth of Pleurotus ostreatus mycelium.

[0094] The results of promoting the growth of Pleurotus ostreatus hyphae by using the growth-promoting bacterial liquid in the Pleurotus ostreatus substrate are shown in Figure 4 And Table 6.

[0095] Table 6 Effects of growth-promoting filtrate at different addition concentrations on the mycelial growth of Pleurotus ostreatus

[0096]

[0097]

[0098] Table 6 compares the growth-promoting effect of the growth-promoting filtrate on the growth of Pleurotus ostreatus hyphae at different addition concentrations. When the addition concentration is 3-7%, the growth-promoting effect on Pleurotus ostreatus shows a gradual increasing trend with the increase of the addition concentration, while when the addition concentration is 9%, the growth rate of Pleurotus ostreatus hyphae begins to decline. When the addition concentration of the bacterial filtrate is 7%, the growth-promoting effect on Pleurotus ostreatus hyphae is the strongest, at which time the growth rate of Pleurotus ostreatus hyphae is 8.48 mm / d and the growth rate is 30.5%. The results show that the growth-promoting bacterial liquid of Pleurotus ostreatus can be applied to the substrate culture of Pleurotus ostreatus in the form of bacterial filtrate, and the addition of 7% bacterial filtrate effectively promotes the substrate culture of Pleurotus ostreatus hyphae.

[0099] In summary, the present invention uses a bacterial separation method to screen out Pleurotus ostreatus growth-promoting bacteria from the Pleurotus ostreatus matrix, and it was identified as Hunan Pseudomonas A12 after genome sequencing. The present invention carried out the application of Pleurotus ostreatus growth-promoting bacteria to the co-cultivation of Pleurotus ostreatus in the laboratory. The results showed that the Pleurotus ostreatus growth-promoting bacteria showed the effect of its living colonies on the Pleurotus ostreatus mycelium plate to promote the growth of Pleurotus ostreatus mycelium; the gas produced by the Pleurotus ostreatus growth-promoting bacteria, and the compound 2-butanone-acetone-styrene in the gas can also effectively promote the growth of Pleurotus ostreatus mycelium in the two-grid plate; and the filtrate of Pleurotus ostreatus growth-promoting bacteria can significantly promote the growth of Pleurotus ostreatus mycelium when added to the solid culture medium and the Pleurotus ostreatus growth matrix at a ratio of 7%. The Pleurotus ostreatus growth-promoting bacteria and its growth-promoting characteristics provided by the present invention can be applied to the artificial cultivation of Pleurotus ostreatus, laying a foundation for effectively shortening the mycelium growth time in artificial cultivation of Pleurotus ostreatus.

[0100] Finally, the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A growth-promoting bacterium for Pleurotus ostreatus, characterized in that: It is Hunan Pseudomonas A12, deposited in the China Type Culture Collection, the collection address is Luojia Mountain, Bayi Road, Wuchang District, Wuhan City, Hubei Province, and the collection number is CCTCC M 20242598.

2. The growth-promoting bacteria of Pleurotus ostreatus according to claim 1, characterized in that: The 16SrRNA gene sequence of the Hunan Pseudomonas A12 is shown in SEQ ID NO:

1.

3. A method for screening Pleurotus ostreatus growth-promoting bacteria as claimed in any one of claims 1 to 2, characterized in that: The following steps are involved: S1. Activation of Pleurotus ostreatus: PDA solid culture medium was used, and the mycelium blocks of Pleurotus ostreatus were inoculated on the PDA solid culture medium, and cultured in the dark at a constant temperature of 28°C; S2. Collection of substrate for oyster mushroom: Collect oyster mushroom bags, remove the mushroom skin, collect substrates with a depth of 2 cm and 10 cm, form a mixed sample, place it in a sealed bag, and keep it fresh at 4°C for 24 hours; S3. Isolation of dominant bacteria: Take the matrix sample treated in step S2, put it into a conical bottle with sterile water, dilute it, spread the dilution on an LB plate, incubate it upside down at 37°C, inoculate bacteria of different morphologies on a new LB plate for streak separation until the bacterial morphology is completely consistent, and store the purified bacteria on a slant at 4°C to obtain the dominant bacteria.

4. An application of the Pleurotus ostreatus growth-promoting bacteria described in any one of claims 1 to 2 or the Pleurotus ostreatus growth-promoting bacteria obtained by the screening method described in claim 3 in promoting the growth of Pleurotus ostreatus.

5. A Pleurotus ostreatus growth-promoting bacteria liquid comprising the Pleurotus ostreatus growth-promoting bacteria according to any one of claims 1 to 3 or the Pleurotus ostreatus growth-promoting bacteria obtained by the screening method according to claim 4.

6. The method for preparing the growth-promoting bacterial liquid of Pleurotus ostreatus according to claim 5, characterized in that: The following steps are involved: Step 1: Inoculate the Pleurotus ostreatus growth-promoting bacteria A12 into the liquid LB culture medium. The culture conditions are: temperature 37°C, rotation speed 200r / min, and shaker culture for 12h. Step 2: The number of viable bacteria of Hunan Pseudomonas A12 is ≥ 10 7 CFU / mL, and then centrifuge to obtain the supernatant. Step 3: Filter the supernatant through a 0.22 μm sterile filter to obtain Pleurotus ostreatus oolong bacteria liquid A12.

7. An application of the Pleurotus ostreatus growth-promoting bacterial liquid according to any one of claims 5 to 6 in promoting the growth of Pleurotus ostreatus.

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