Prosteria ataveovii strain and application thereof

Abstract

The invention belongs to the technical field of microorganisms, and particularly relates to a Prlisteria ataveovii strain and application thereof. The invention provides a Pichia aryabhattai B8, which is preserved in the General Microbiological Culture Collection Center of the China Committee for Culture Collection of Microorganisms, the preservation date is September 10, 2024, and the preservation number is CGMCC No.31932. The Pichia aryabhattai B8 disclosed by the invention has the advantages that the Pichia aryabhattai B8 can be used for preparing the Pichia aryabhattai B8; the prelisteria aryabhattai B8 disclosed by the invention has a relatively strong function of producing indoleacetic acid, and the content of indoleacetic acid in plants can be increased, so that the stress resistance of the plants is improved; dissolution of insoluble phosphorus and potassium in soil can be promoted, soil nutrients are improved, plant growth is promoted, and plant quality is improved; and meanwhile, the P.aryabhattai B8 has a certain antagonistic effect on pathogenic bacteria of the wheat root rot, and can be used for preventing and treating the wheat root rot.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and in particular relates to a Priesteria africana strain and application thereof. Background Art

[0002] Yellow-brown soil refers to soil under the northern subtropical deciduous evergreen broad-leaved forest, which has undergone strong leaching, is strongly acidic, and is weakly aluminum-rich with unsaturated bases. Yellow-brown soil is used for wheat, a major crop in the temperate zone, and indica rice, a characteristic of the subtropics, as well as cash crops such as tobacco. However, due to continuous cropping obstacles, the physical and chemical properties of tobacco-growing soil have deteriorated, tobacco leaf yield and quality have declined, and high-quality tobacco areas have continued to shrink. Therefore, reducing the continuous cropping obstacles in yellow-brown soil tobacco fields will help improve tobacco leaf quality and yield, maintain soil health, improve resource utilization efficiency, and promote sustainable agricultural development.

[0003] Plant growth promoting rhizobacteria (PGPR) refers to a type of beneficial bacteria that live freely in the soil or are attached to the roots of plants and can promote plant growth and its absorption and utilization of mineral nutrients, and can inhibit harmful organisms. PGPR can synthesize substances that have a direct effect on plant growth and development, such as plant hormones to promote plant growth. It can also change the form of certain ineffective elements in the soil, such as promoting the dissolution of insoluble phosphorus and potassium in the soil, making them effective and conducive to plant absorption. However, there are currently few reports on multifunctional growth-promoting bacteria that can dissolve phosphorus and potassium, produce hormones, and resist diseases. There is an urgent need for a multifunctional growth-promoting bacterium to improve soil properties. Summary of the invention

[0004] The purpose of the present invention is to provide a strain of Priesteria afrozenii and an application thereof. The Priesteria afrozenii B8 of the present invention has a strong indoleacetic acid production function, can promote the dissolution of insoluble phosphorus and potassium in the soil, promote plant growth, improve plant quality, and has an antagonistic effect on wheat root rot pathogens.

[0005] The present invention provides a strain of Priestia aryabhattai B8, which is deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with a deposit date of September 10, 2024 and a deposit number of CGMCC No.31932.

[0006] The present invention also provides a bacterial agent, the active ingredients of which include the Prioccidioides aeruginosa B8 described in the above scheme.

[0007] As a preferred embodiment, the effective viable count of A. aegypti B8 in the bacterial agent is ≥ 1×10 11 CFU / g.

[0008] The present invention also provides an application of the Affymetrix axeter B8 or the bacterial agent described in the above scheme, wherein the application comprises at least one of the following 1) to 5):

[0009] 1) Prevent and control wheat root rot;

[0010] 2) Increase the indoleacetic acid content of plants;

[0011] 3) Promote plant growth;

[0012] 4) Improve soil nutrients;

[0013] 5) Improve plant quality.

[0014] As a preferred embodiment, the promoting plant growth includes at least one of promoting root growth, increasing plant height and increasing leaf area.

[0015] As a preferred embodiment, the plant includes at least one of tobacco, cotton, fruit trees, Chinese cabbage, tomatoes, wheat, millet, corn and sorghum.

[0016] As a preferred embodiment, the improving soil nutrients includes promoting the dissolution of insoluble phosphorus and / or potassium in the soil.

[0017] As a preferred embodiment, the improving plant quality comprises increasing at least one of the total sugar, reducing sugar and potassium content of the plant.

[0018] As a preferred embodiment, the application comprises the following steps: applying the Afrikaans bacterium B8 or the bacterial agent described in the above embodiment to soil in which plants are planted.

[0019] As a preferred solution, the amount of the bacterial agent applied is 35-45 kg / hm 2 .

[0020] Beneficial effects:

[0021] The present invention provides a strain of Priestia aryabhattai B8, which is deposited in the General Microbiology Center of the China Microbiological Culture Collection Administration Committee, with a deposit date of September 10, 2024, and a deposit number of CGMCC No. 31932. The concentration of indole-3-acetic acid (IAA) produced by Priestia aryabhattai B8 of the present invention can reach 67.41 mg / L or more, which can directly promote the elongation of plant roots and increase the chance of contact with nutrients in the soil; and can increase the content of endogenous IAA in plants, induce the expression of plant defense genes, and improve the resistance of plants to diseases, drought and other stresses. In addition, the Priestia aryabhattai B8 of the present invention has the ability to dissolve phosphorus, and the concentration of dissolving poorly soluble inorganic phosphorus reaches 532.33 mg / L or more, which can convert phosphorus that is difficult to use into available phosphorus and increase the content of available phosphorus in the soil. In addition, the Afrococcus avorein B8 of the present invention also has the ability to dissolve potassium, and the solubility of the insoluble potassium reaches more than 275.01 mg / L, which can improve the utilization rate of fertilizers, promote the growth and development of plants and the absorption of fertilizers. At the same time, the Afrococcus avorein B8 of the present invention has a certain antagonistic effect on wheat root rot pathogens, and has the potential for biocontrol applications.

[0022] The avopristriatus B8 of the present invention can promote plant growth. The results of the examples show that the application of avopristriatus B8 to tobacco, Chinese cabbage and wheat potted plants can promote the increase of IAA content and nutrient content in the soil, and at the same time promote the root system of the crop to be thicker and longer with a larger surface area, which is beneficial to the absorption of water and nutrients by the crop root system, so that the plant height and dry weight and fresh weight of the aboveground part of the crop are significantly higher than the control treatment. In the tobacco field test, compared with the control, the avopristriatus B8 treatment of the present invention makes the tobacco have a higher plant height and leaf area, and promotes the increase of tobacco yield; the content of total sugar and reducing sugar in the tobacco after baking is increased by 11.88% and 15.25% respectively compared with the control treatment, and the potassium content in the tobacco leaves after baking is significantly increased by 20.86% compared with the control treatment. Avopristriatus B8 can improve the yield and quality of tobacco. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0024] Figure 1 This is the colony map of strain B8 of the present invention;

[0025] Figure 2 is a phylogenetic tree of Priesteria axyri B8 of the present invention;

[0026] Figure 3This is a diagram showing the antagonistic effect of Priesteria axyridis B8 on wheat root rot pathogens; A is a diagram showing the effect without inoculation with Priesteria axyridis B8; and B is a diagram showing the effect with inoculation with Priesteria axyridis B8.

[0027] Biological Deposit Description

[0028] Priestia aryabhattai B8 was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on September 10, 2024. The unit is abbreviated as CGMCC. The address is Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The deposit number is CGMCC No.31932 and the strain number is B8. DETAILED DESCRIPTION

[0029] The present invention provides a strain of Priestia aryabhattai B8, which is deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with a deposit date of September 10, 2024 and a deposit number of CGMCC No.31932.

[0030] The bacterial morphology of the afrococcal bacterium B8 described in the present invention is as follows: it has a capsule, no spores, has a monopolar flagellum, can move, and can form a 2mm colony after being cultured on a selective medium for 24 hours; the colony morphology is that the colony is slightly yellow, round, has a convex surface, is smooth and moist, is relatively sticky, is easy to pick up, and has neat edges; the physiological and biochemical characteristics of the afrococcal bacterium B8 are: Gram-positive, facultative anaerobic, catalase-positive, MR test-negative, and VP test-negative.

[0031] In the present invention, the Prioclonia ovale B8 has the ability to secrete IAA and promote the dissolution of insoluble phosphorus and potassium in the soil; the Prioclonia ovale B8 secretes IAA up to 67.41 mg / L, has the ability to dissolve inorganic phosphorus up to 532.33 mg / L, and has the ability to dissolve potassium up to 275.01 mg / L.

[0032] The present invention also provides a bacterial agent, wherein the active ingredient of the bacterial agent includes the Priesteria aztecii B8 described in the above scheme. As an embodiment, the effective viable count of Priesteria aztecii B8 in the bacterial agent is ≥ 1×10 11 CFU / g. In the present invention, the bacterial agent includes Apricot B8 and a carrier; the present invention has no special restrictions on the type of the carrier, and a carrier of a bacterial agent known in the art can be used; in an embodiment of the present invention, the type of the carrier is bone powder. The present invention has no special restrictions on the preparation method of the bacterial agent, and a preparation method of a bacterial agent known in the art can be used.

[0033] The present invention also provides an application of the Apricot B8 described in the above scheme or the bacterial agent described in the above scheme, wherein the application includes at least one of the following 1) to 5): 1) preventing and controlling wheat root rot; 2) increasing the indoleacetic acid content of plants; 3) promoting plant growth; 4) increasing soil nutrients; 5) improving plant quality.

[0034] As an embodiment, the Apricot B8 described in the present invention has a certain antagonistic effect on wheat root rot pathogens and can be used to prevent and control wheat root rot.

[0035] As an embodiment, the plant growth promotion includes at least one of promoting root growth, increasing plant height and increasing leaf area. As an embodiment, the plant includes at least one of tobacco, cotton, fruit trees, Chinese cabbage, tomatoes, wheat, millet, corn and sorghum. The indoleacetic acid produced by the apricot bacteria B8 of the present invention can directly promote the growth of plant roots, making the roots thicker, longer and having a larger surface area, thereby increasing the opportunity for the plant to contact nutrients in the soil and increasing the plant height, leaf area and dry weight and fresh weight of the aboveground part of the plant.

[0036] As an embodiment, the improvement of soil nutrients includes promoting the dissolution of insoluble phosphorus and / or potassium in the soil. The concentration of insoluble inorganic phosphorus dissolved by the Apricot B8 of the present invention reaches 532.33 mg / L or more, which can convert insoluble phosphorus into available phosphorus and increase the content of effective phosphorus in the soil; and the strain also has the ability to dissolve potassium, and the solubility of insoluble potassium reaches 275.01 mg / L or more, thereby improving the utilization rate of fertilizers and promoting the growth and development of plants and the absorption of fertilizers.

[0037] As an embodiment, the improving plant quality includes increasing at least one of the total sugar, reducing sugar and potassium content of the plant. In the present invention, the Apricot B8 can increase the total sugar, reducing sugar and potassium content in the flue-cured tobacco, thereby improving the yield and quality of the tobacco.

[0038] As an embodiment, the application comprises the following steps: applying the Apricot B8 described in the above scheme or the bacterial agent described in the above scheme to soil in which plants are planted. As an embodiment, the water content of the soil is 50% to 60% of the maximum water holding capacity in the field.

[0039] As an embodiment, before applying the Afapristria B8 to the soil planted with plants, it also includes: expanding the culture of Afapristria B8 to obtain a bacterial suspension. In the present invention, the pH of the culture medium for the expanded culture is 6-8; the culture medium for the expanded culture includes an inorganic salt culture medium; the inorganic salt includes one or more of sodium chloride, potassium chloride, tricalcium phosphate, ammonium sulfate, magnesium sulfate heptahydrate, manganese sulfate and ferrous sulfate heptahydrate. As an embodiment, the inorganic salt culture medium of the present invention also includes the following mass percentage components per 1000mL: 1% carbon source and 0.05%-0.1% nitrogen source; as an embodiment, the carbon source includes one or more of glucose, sucrose, and maltose; the nitrogen source includes one or more of urea, peptone, and yeast powder. The present invention has no special restrictions on the sources of the carbon source, nitrogen source and inorganic salt, and the sources of the above-mentioned carbon source, nitrogen source and inorganic salt known to those skilled in the art can be used. As an embodiment, the time of the expanded culture is 68h. In the present invention, the expanded culture is shaking culture, the rotation speed of the shaking culture is 180 rpm; the volume of the culture medium during the shaking culture is 30-70 mL / 250 mL conical flask.

[0040] As an embodiment, the amount of Apricot B8 applied is 1 to 9×10 8 CFU / g soil. In a specific embodiment of the present invention, the amount of A. aegypti B8 applied can be 1 to 9×10 8 CFU / g soil. As an embodiment, the amount of the bacterial agent applied is 35-45 kg / hm 2 In a specific embodiment of the present invention, the amount of the bacterial agent applied can be 35-45 kg / hm 2 As an embodiment, the effective viable count of A. aegypti B8 in the bacterial agent is 1 to 9×10 11 CFU / g. In a specific embodiment of the present invention, the effective viable count of A. aegypti B8 in the bacterial agent may be 1 to 9×10 11 Arbitrary value of CFU / g.

[0041] In order to further illustrate the present invention, a strain of Priesteria afroicola and its application provided by the present invention are described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the protection scope of the present invention.

[0042] Example 1

[0043] (1) Preparation of experimental culture medium

[0044] LB medium: 10g peptone, 5g yeast extract, 10g sodium chloride, 20g agar and 1000mL distilled water, pH 7.0-7.2, sterilized at 121℃ for 20min. On this basis, without adding agar, it is LB liquid medium.

[0045] Inorganic phosphorus bacterial culture medium (PKO medium): 5 g tricalcium phosphate, 10 g glucose, 0.5 g ammonium sulfate, 0.3 g sodium chloride, 0.3 g magnesium sulfate heptahydrate, 0.3 g potassium chloride, 0.03 g manganese sulfate, 0.03 g ferrous sulfate heptahydrate and 1000 mL of distilled water, pH 7.0-7.2, sterilization at 121°C for 20 min.

[0046] Liquid potassium-dissolving bacterial culture medium: sucrose 10.0 g, yeast extract 0.5 g, ammonium sulfate 1.0 g, sodium dihydrogen phosphate 2.0 g, magnesium sulfate heptahydrate 0.5 g, CaCO3 1.0 g, feldspar powder 1.0 g and distilled water 1000 mL, sterilized at 121°C for 20 min.

[0047] Inorganic salt culture medium: 2.0 g ammonium sulfate, 0.5 g sodium dihydrogen phosphate, 0.5 g dipotassium hydrogen phosphate, 0.2 g magnesium sulfate heptahydrate, 0.1 g calcium chloride dihydrate and 1000 mL distilled water, pH 7.0, sterilize at 121°C for 20 min.

[0048] (2) Isolation of bacteria

[0049] A. Collect 10g of natural tobacco-growing soil from Luoshan County, Xinyang City, Henan Province. The soil is yellow-brown soil, and its basic physical and chemical properties are shown in Table 1. B. Place the soil collected in step A in a 250mL Erlenmeyer flask containing 100mL of sterilized water, shake it in a shaker at 30°C and 150rpm for 20min, and let it stand for 10min to obtain a soil bacterial suspension. C. The soil bacterial suspension obtained in step B contains several types of rhizosphere growth-promoting bacteria. After dilution by the dilution method, apply it to LB culture medium, invert the plate, and culture it in a constant temperature box at 30°C for 24h. Pick out typical single colonies of different types, purify them on the plate, and store them on the LB slant at 4°C, and configure OD 600 The seed solution with a concentration of 1 is set aside, and the plant growth-promoting bacteria that can secrete indoleacetic acid are screened out through qualitative and quantitative determination.

[0050] Table 1 Basic physical and chemical properties of the tested soil

[0051]

[0052] (3) Qualitative determination

[0053] A. The bacteria separated and purified in step (2) were inoculated with 1% of the seed liquid into LB liquid medium containing L-tryptophan (100 mg / L) and cultured at 30°C and 180 rpm on a shaker for 1 day. B. After the culture was completed, 50 μL of the bacterial suspension in step A was dropped onto a white ceramic plate, and 50 μL of Salkowski colorimetric solution (50 mL 35% (w / v) HClO4 + 1 mL 0.5 M FeCl3) was added at the same time. C. The positive control group was: 50 μL of 50 mg / L indoleacetic acid and 50 μL Salkowski colorimetric solution were added onto the white ceramic plate. D. The white ceramic plate was placed at room temperature and away from light for 30 minutes and then observed. The color turned red, indicating that the plate was able to secrete indoleacetic acid.

[0054] (4) Quantitative determination

[0055] A. Quantitative determination of IAA-secreting bacteria obtained by qualitative determination in step (3) was performed, and the culture conditions were the same as those in step (3) A. B. Centrifuge the culture solution in step A at 10,000 rpm for 10 min, take the supernatant and add an equal volume of Salkowski colorimetric solution, keep it in the dark for 30 min, and determine its OD 530 The standard curve was drawn using gradient dilutions of analytically pure indoleacetic acid to detect the content of IAA in each L of fermentation broth and to determine the ability of the strain to produce IAA. The results are shown in Table 2.

[0056] (5) Screening bacteria with better IAA production for determination of phosphorus and potassium solubilization abilities

[0057] A. The seed liquid of the isolated strain was inoculated into a 250mL Erlenmeyer flask containing 50mL of inorganic phosphorus culture medium at a 1% inoculation rate, and placed in a shaker with the shaker temperature set at 30°C and the speed set at 180rpm for 3 days. B. After the culture was completed, the culture solution was centrifuged at 10,000rpm for 5 minutes in a 2mL centrifuge tube, the centrifuge tube was taken out, the supernatant was transferred, and the effective phosphorus content was determined by the molybdenum blue colorimetric method. The phosphorus solubilizing ability of the strain was determined by the effective phosphorus content in the supernatant. The results are shown in Table 2.

[0058] (6) Screening bacteria with better IAA production and measuring potassium-solubilizing ability

[0059] A. Inoculate the seed liquid of the isolated strain at a 1% inoculation rate into a 250mL Erlenmeyer flask containing 50mL of liquid potassium-solubilizing bacterial culture medium, place it in a shaker, set the shaker temperature to 30°C, the speed to 180rpm, and culture for 3 days. B. After the culture is completed, centrifuge the culture solution at 10000rpm for 10min in a 10mL centrifuge tube, take out the centrifuge tube, transfer the supernatant, and determine the potassium content with a flame spectrophotometer. The potassium content in the supernatant is used to determine the potassium-solubilizing ability of the strain. The results are shown in Table 2.

[0060] Through the above determination, a strain with high indoleacetic acid production and strong phosphorus and potassium solubilization ability was screened out and named B8. The colony diagram is shown in Figure 1 shown.

[0061] Table 2 Growth-promoting ability of strain B8

[0062] Test strains IAA production capacity (mg / L) Solubility of inorganic phosphorus (mg / L) Potassium dissolving capacity (mg / L) B8 67.41 532.33 275.01

[0063] According to Table 2, the isolated strain B8 has the ability to secrete IAA, reaching 67.41 mg / L; and the strain B8 has the ability to solubilize inorganic phosphorus, reaching 532.33 mg / L; and has the ability to solubilize potassium, reaching 275.01 mg / L.

[0064] (7) Aerobic test

[0065] Pour the sterilized LB medium into three sterilized test tubes. At about 2 / 3 of the tube, use an inoculation needle to pick up the strain B8 cultured on the slant and puncture it into the above medium (must puncture to the bottom of the tube). Incubate at 30℃ and observe the results at 3 to 7 days.

[0066] Those growing on the surface of the agar column are aerobic bacteria, and those growing along the puncture line are anaerobic bacteria or facultative anaerobic bacteria. The test results show that the colonies of strain B8 grow along the surface of the agar column and also grow inside the puncture line, which is facultative anaerobic.

[0067] (8) Determination of catalase

[0068] Drop 1 drop of 3% H2O2 on a clean glass slide, use an inoculation loop to take 1 loop of the strain B8 culture cultured on the LB slant for 18 to 24 hours, and smear it in H2O2. If bubbles are generated, it is positive, otherwise it is negative. The test results are shown in Table 3, and the results show that strain B8 is catalase positive.

[0069] (9) Methyl red test (MR test)

[0070] A. Prepare the culture medium: 5g peptone, 5g glucose, 5g sodium chloride and 1000mL distilled water, adjust pH to 7.0-7.2, divide into test tubes, 4-5mL per tube, sterilize at 121℃ for 20min. Required reagents: 0.1g methyl red, 300mL 95% alcohol, 200mL distilled water.

[0071] B. Bacterial culture and observation of results: Inoculate strain B8 in the above culture medium and culture at 30℃ for 1 to 2 days. Add a few drops of methyl red reagent to the culture medium. If the culture medium turns red, it is methyl red positive, and yellow is negative (methyl red color range 4.4 red to 6.0 yellow). The test results are shown in Table 3, and the results show that strain B8 is methyl red negative.

[0072] (10) Acetyl methyl carbinol test (VP test)

[0073] A. Culture medium preparation is the same as step (9) for methyl red test.

[0074] B. Bacterial culture and observation of results: Inoculation and culture are the same as step (9) methyl red test. When doing the VP test, take the culture solution (about 2 mL) and mix it with an equal amount of 40% NaOH, add a small amount of creatine, and shake it thoroughly for 2 to 5 minutes. If the culture solution turns red, it is VP positive. The test results are shown in Table 3, and the results show that strain B8 is VP negative.

[0075] (11) Starch hydrolysis test

[0076] A. ① Culture medium preparation: add 0.2% soluble starch to broth peptone agar, dispense into triangular bottles, sterilize at 121℃ for 20min for later use. ② Lugo's iodine solution: 1g iodine tablets, 2g potassium iodide, first dissolve potassium iodide in a small amount (3-5mL) of distilled water, then add iodine tablets, and dilute to 300mL with water after the iodine is completely dissolved.

[0077] B. Bacterial culture and observation of results: Take B8 bacteria and inoculate it on the plate, culture it at 30℃ for 2-4 days. After the colonies are formed, add Lugo's iodine solution on the plate until it covers the colonies. The plate will be blue, and if there is a colorless transparent circle around the colonies, it means that the starch has been hydrolyzed. The size of the transparent circle generally indicates the ability to hydrolyze starch. The test results are shown in Table 3, and the results show that strain B8 is positive for starch hydrolysis.

[0078] (12) Gelatin hydrolysis test

[0079] A. Culture medium preparation: 5 g of peptone, 120 g of gelatin and 1000 mL of distilled water, adjust pH to 7.2-7.4, divide into test tubes, the culture medium height is about 4-5 cm, and sterilize at 121°C for 20 min.

[0080] B. Bacterial culture and observation: Inoculate strain B8 in the center of the test tube by puncture method, culture in a 30℃ incubator for one month, and observe whether the gelatin is liquefied. The test results are shown in Table 3, and the results show that strain B8 is positive for gelatin hydrolysis.

[0081] (13) Nitrate reduction test

[0082] A. ① Nitrate liquid culture medium: 10g peptone, 1g potassium nitrate and 1000mL distilled water, pH7.0-7.4. ② Gries reagent: Solution A: 0.5g p-aminobenzenesulfonic acid, 150mL dilute acetic acid (about 10%); Solution B: 0.1g dapoxetine, 20mL distilled water, 150mL dilute acetic acid (about 10%). ③ Diphenylamine reagent: 0.5g diphenylamine is dissolved in 100mL concentrated sulfuric acid and diluted with 20mL distilled water.

[0083] B. Bacteria culture and observation of results: Inoculate strain B8 in nitrate liquid culture medium and culture at 30℃ for 1, 3, and 5 days. Pour a small amount of culture solution into the small hole of a white porcelain plate, and then drop 1 drop of reagent A and B solution into it respectively. When the culture solution turns pink, rose red, orange or brown, it indicates the presence of nitrite, which is positive for nitrate reduction, otherwise it is negative. The test results are shown in Table 3, and the results show that strain B8 is positive for nitrate reduction.

[0084] (14) Utilization of Citrate

[0085] A. Culture medium configuration: 2 g sodium citrate, 5 g sodium chloride, 0.2 g magnesium sulfate heptahydrate, 1 g diammonium phosphate, 10 mL 1% thymol blue aqueous solution, 20 g agar and 1000 mL distilled water, pH 6.8-7.0, sterilize at 121°C for 20 min.

[0086] B. Culture of strains and observation of results: Take fresh B8 strains and inoculate them on the slant, culture at 30℃ for 3-7 days, if the culture medium is alkaline (blue), it is a positive reaction, if it remains unchanged, it is a negative reaction. The test results are shown in Table 3, and the results show that strain B8 is positive.

[0087] Table 3 Physiological and biochemical characteristics of strain B8

[0088] project result project result Gram stain + Starch hydrolysis + Aerobic test Facultative anaerobic Gelatin liquefaction + Catalase test + Nitrate reduction + Methyl red (MR) reaction - Citrate Utilization + VP test - / /

[0089] Note: +: positive reaction; -: negative reaction

[0090] The strain B8 isolated by the above method was sequenced by Shanghai Yingjun Bioengineering Co., Ltd., and the sequencing results of 16S rDNA were searched and analyzed online at http: / / www.ncbi.nlm.nih.gov. The homology was compared with other 16S rDNA sequences in GenBank using Blast software, and the similar sequences were selected to construct the 16S rDNA phylogenetic tree of strain B8 using MEGAversion3 software, as shown in the following figure. Figure 2The sequence information of 16S rDNA of the strain B8 is shown in SEQ ID NO. 1. According to the physiological and biochemical characteristics of the strain, it was identified as Priestia aryabhattai, and the strain was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on September 10, 2024, with the deposit number CGMCC No. 31932.

[0091] The bacterial morphology of the strain B8 is as follows: it has a capsule, no spores, has a monopolar flagellum, can move, and can form 2mm colonies after culturing on a selective medium for 24 hours; the colony morphology is that the colonies are slightly yellow, round, convex on the surface, smooth and moist, relatively sticky, easy to pick up, and have neat edges; the physiological and biochemical characteristics of the strain B8 are: Gram-positive, facultative anaerobic, catalase positive, MR test negative, and VP test negative.

[0092] Example 2

[0093] (1) In order to further verify the ability and optimal conditions of the rhizosphere growth-promoting bacteria Apricotibacterium oxysporum B8 obtained in Example 1 to produce indoleacetic acid, the effects of different pH, liquid volume, different carbon sources, and different nitrogen sources on the production of indoleacetic acid were explored.

[0094] Four factors, carbon source, nitrogen source, pH and liquid volume, were selected for orthogonal test. The level of each factor is set as shown in Table 4. The inorganic salt medium containing 100 mg / L of L-tryptophan was adjusted respectively. Among them, the carbon and nitrogen sources were added in the amount of 1% and 0.1% (M / V), respectively. The selected strains were inoculated in a 250 mL Erlenmeyer flask and cultured at 30°C and 180 rpm for 1 day. The amount of IAA produced was determined by Salkowski colorimetry. The results are shown in Table 5.

[0095] Table 4 Orthogonal table for optimizing growth-promoting function of strain B8

[0096] Different conditions Carbon source Nitrogen source pH Liquid volume (mL / 250mL) 1 maltose Urea 6 30 2 maltose Yeast powder 7 50 3 maltose Peptone 8 70 4 glucose Urea 7 70 5 glucose Yeast powder 8 30 6 glucose Peptone 6 50 7 sucrose Urea 8 50 8 sucrose Yeast powder 6 70 9 sucrose Peptone 7 30

[0097] Table 5 Results of orthogonal test on IAA production ability of strain B8

[0098]

[0099] Note: K1, K2, K3 represent the average values ​​of each factor, and R represents the maximum range among K1, K2, K3.

[0100] According to Table 5, the influence of various factors on the IAA production ability of strain B8 is in the order of liquid volume > carbon source > pH > nitrogen source. Based on the means of the four factors and intuitive analysis, the optimal condition combination for B8 to produce IAA is maltose as the carbon source, peptone as the nitrogen source, pH of 7, and liquid volume of 70mL / 250mL.

[0101] (2) In order to further verify the inorganic phosphorus solubilizing ability and optimal conditions of the rhizosphere growth-promoting bacteria B8 obtained in Example 1, the effects of different pH, liquid volume, different carbon sources, and different nitrogen sources on the inorganic phosphorus solubilizing ability were explored.

[0102] Four factors, carbon source, nitrogen source, pH and liquid volume, were selected for orthogonal experiment. The level of each factor was set as shown in Table 4, and the inorganic phosphorus bacterial culture medium was adjusted respectively. Among them, the carbon and nitrogen sources were added in the amount of 1% and 0.1% (M / V), respectively, and the selected strains were inoculated in a 250mL Erlenmeyer flask, placed at 30°C and 180rpm for 3 days, and the phosphorus content of the supernatant was determined by molybdenum blue colorimetry. The results are shown in Table 6.

[0103] Table 6 Results of orthogonal test on solubilization of inorganic phosphorus by strain B8

[0104]

[0105] Note: K1, K2, K3 represent the average values ​​of each factor, and R represents the maximum range among K1, K2, K3.

[0106] According to Table 6, the influence of various factors on the ability of strain B8 to solubilize inorganic phosphorus is in the order of pH>liquid volume>nitrogen source>carbon source. Based on the means of the four factors and intuitive analysis, the optimal combination of conditions for B8 to solubilize inorganic phosphorus is glucose as the carbon source, urea as the nitrogen source, pH of 7, and liquid volume of 50mL / 250mL.

[0107] (3) In order to further verify the optimal conditions for the potassium solubilization ability of the rhizosphere growth-promoting bacteria B8 obtained in Example 1, the effects of different pH, liquid volume, different carbon sources, and different nitrogen sources on the indoleacetic acid production were explored.

[0108] Four factors, carbon source, nitrogen source, pH and liquid volume, were selected for orthogonal test. The level of each factor was set as shown in Table 4, and the liquid potassium-solubilizing bacterial culture medium was adjusted respectively. Among them, the carbon and nitrogen sources were added in the amount of 1% and 0.1% (M / V) respectively, and the selected strains were inoculated into a 250mL triangular flask, and cultured continuously for 3 days at 30°C and 180rpm. The supernatant was centrifuged and the available potassium content was determined by flame spectrophotometer. The results are shown in Table 7.

[0109] Table 7 Results of orthogonal test on potassium solubilization ability of strain B8

[0110]

[0111] Note: K1, K2, K3 represent the average values ​​of each factor, and R represents the maximum range among K1, K2, K3.

[0112] According to Table 7, the influence of various factors on the potassium-solubilizing ability of strain B8 is in the order of carbon source>nitrogen source>liquid volume>pH. Based on the means of the four factors and intuitive analysis, the best combination of conditions for the potassium-solubilizing ability of B8 is maltose as the carbon source, peptone as the nitrogen source, pH of 8, and liquid volume of 50mL / 250mL.

[0113] Example 3

[0114] In order to explore the biocontrol ability of strain B8, the pathogens of wheat root rot, bitter melon wilt, apple rot and tobacco black shank in the laboratory were used as test pathogens, and the antagonistic function of strain B8 was explored respectively.

[0115] The plate confrontation method was used to detect the antagonistic activity of the isolated and purified strain B8 with pathogens as the target. The pathogen cake was placed in the center of the OA plate, and the strain was inoculated around the pathogen cake. Three replicates were set up, with only the pathogen cake as the control, and cultured at 28°C. The antagonistic ability was determined based on whether there was an inhibition zone.

[0116] The results showed that strain B8 showed a better antagonistic ability to wheat root rot pathogens. In the OA medium without strain B8 inoculation, the wheat root rot pathogens had already grown all over the culture dish ( Figure 3 A), while in the medium inoculated with strain B8, an obvious inhibition zone appeared around strain B8 ( Figure 3 (middle B).

[0117] Example 4

[0118] (1) Preparation of bacterial suspension: The strain B8 isolated in Example 1 was inoculated into LB liquid culture medium and cultured in a shaking incubator at 30° C. and 180 rpm to grow the cultured bacteria to the logarithmic growth phase; the bacterial solution was then centrifuged at 3000 rpm for 10 min, resuspended in sterile water, and centrifuged three times to prepare a bacterial suspension.

[0119] (2) Preparation of test soil: Fresh soil from the 0-20 cm soil layer of natural tobacco-growing soil in Luoshan County, Xinyang City, Henan Province was collected and passed through a 5 mm sieve. 700 g of soil was placed in each pot, and the water content was adjusted to 60% of the maximum field water holding capacity. The soil was randomly divided into an experimental group (B8) and a control group (CK).

[0120] (3) Seed treatment: Use 20% hydrogen peroxide to disinfect the surface of tobacco seeds for 20 minutes, rinse with sterile water for multiple times, and germinate for 2 days; select tobacco seedlings with consistent germination and inoculate them into the soil of the experimental group and the control group in step (2) respectively.

[0121] (4) Experimental group: The bacterial suspension in step (1) was added at 10 8 CFU / g soil inoculation rate, 24h before seedling transplanting, inoculate into the soil (i.e., 10 CFU / g soil per gram of dry soil)8 CFU / g of A. aegypti B8).

[0122] Control group: As a control, the soil was not sprayed with B8 bacterial solution, but an equal amount of sterile water was added.

[0123] Each treatment was repeated 4 times. The potted plants were placed in a light culture room and samples were collected after 30 days. The soil IAA content was determined by HPLC. The soil pH, organic matter, alkaline nitrogen, available phosphorus, available potassium content, plant fresh weight, plant height, and total nitrogen, total phosphorus, and total potassium contents were also determined. The results are shown in Tables 8 and 9.

[0124] Table 8 Effects of strain B8 on the physical and chemical properties of tobacco potted soil

[0125]

[0126] Note: “*” indicates significant difference among treatments (p<0.05), and “**” indicates extremely significant difference among treatments (p<0.01).

[0127] Table 9 Effects of strain B8 on tobacco biological traits

[0128]

[0129] Note: “*” indicates significant difference among treatments (p<0.05), and “**” indicates extremely significant difference among treatments (p<0.01).

[0130] According to Table 8, after inoculation with A. aegypti B8, the contents of IAA, available phosphorus, and available potassium in the soil increased significantly by 66.67%, 35.68%, and 18.50% respectively compared with the CK treatment, indicating that A. aegypti B8 can effectively increase the nutrient content in the soil to promote the growth of tobacco. According to Table 9, after inoculation with A. aegypti B8, the plant height, fresh weight, root surface area, and root volume of tobacco seedlings increased significantly by 10.84%, 16.39%, 12.07%, and 32.64% respectively compared with the CK treatment.

[0131] Based on the above results, it can be seen that the multifunctional rhizosphere growth-promoting bacteria Prioccidioides africanus B8 of the present invention can effectively increase the nutrient content of soil, has a significant effect on promoting the growth and development of tobacco roots, and can effectively promote the growth of tobacco.

[0132] Example 5

[0133] (1) Preparation of bacterial suspension: The bacterial suspension of Apricot B8 was prepared according to step (1) in Example 4.

[0134] (2) Preparation of test soil: Soil was collected according to step (2) in Example 4 and randomly divided into an experimental group (B8) and a control group (CK).

[0135] (3) Seed treatment: Use 20% hydrogen peroxide to disinfect the surface of Chinese cabbage seeds for 20 minutes, rinse with sterile water for multiple times, and germinate for 2 days; select Chinese cabbage seedlings with consistent germination and inoculate them into the soil of the experimental group and the control group in step (2) respectively.

[0136] (4) Experimental group: The bacterial suspension in step (1) was added at 10 8 CFU / g soil inoculation rate, 24h before seedling transplanting, inoculate into the soil (i.e., 10 CFU / g soil per gram of dry soil) 8 CFU / g of A. aegypti B8).

[0137] Control group: As a control, the soil was not sprayed with B8 bacterial solution, but an equal amount of sterile water was added.

[0138] Each treatment was repeated 4 times. The potted plants were placed in a light culture room and samples were taken after 30 days. The soil IAA content, soil available phosphorus and available potassium content, plant fresh weight, plant height, and total nitrogen, total phosphorus and total potassium contents were determined by HPLC. The results are shown in Tables 10 and 11.

[0139] Table 10 Effects of strain B8 on the physical and chemical properties of potted soil for Chinese cabbage

[0140]

[0141] Note: “*” indicates significant difference among treatments (p<0.05), and “**” indicates extremely significant difference among treatments (p<0.01).

[0142] Table 11 Effects of strain B8 on biological characteristics of Chinese cabbage

[0143]

[0144] Note: “*” indicates significant difference among treatments (p<0.05), and “**” indicates extremely significant difference among treatments (p<0.01).

[0145] According to Table 10, after inoculation with A. aegypti B8, the contents of IAA, available phosphorus, and available potassium in the soil increased significantly by 71.43%, 33.44%, and 18.51% respectively compared with the CK treatment, indicating that A. aegypti B8 can effectively increase the nutrient content in the soil to promote the growth of Chinese cabbage. According to Table 11, after inoculation with A. aegypti B8, the dry weight, root surface area, and root volume of Chinese cabbage seedlings increased significantly by 40.00%, 16.58%, and 16.00% respectively compared with the CK treatment.

[0146] Based on the above results, it can be seen that the multifunctional rhizosphere growth-promoting bacteria Prioccidioides aeruginosa B8 of the present invention can effectively increase the nutrient content of the soil, has a significant effect on promoting the growth and development of the root system of Chinese cabbage, and can effectively promote the growth of Chinese cabbage.

[0147] Example 6

[0148] (1) Preparation of bacterial suspension: The bacterial suspension of Apricot B8 was prepared according to step (1) in Example 4.

[0149] (2) Preparation of test soil: Soil was collected according to step (2) in Example 4 and randomly divided into an experimental group (B8) and a control group (CK).

[0150] (3) Seed treatment: Use 20% hydrogen peroxide to disinfect the surface of wheat seeds for 20 minutes, rinse with sterile water for multiple times, and germinate for 2 days; select wheat seedlings with consistent germination and inoculate them into the soil of the experimental group and the control group in step (2), respectively.

[0151] (4) Experimental group: The bacterial suspension in step (1) was added at 10 8 CFU / g soil inoculation rate, 24h before seedling transplanting, inoculate into the soil (i.e., 10 CFU / g soil per gram of dry soil) 8 CFU / g of A. aegypti B8).

[0152] Control group: As a control, the soil was not sprayed with B8 bacterial solution, but an equal amount of sterile water was added.

[0153] Each treatment was repeated 4 times. The potted plants were placed in a light culture room and samples were taken after 30 days. The soil IAA content, soil available phosphorus and available potassium content, plant fresh weight, plant height, and total nitrogen, total phosphorus and total potassium content were determined by HPLC. The results are shown in Tables 12 and 13.

[0154] Table 12 Effects of strain B8 on the physical and chemical properties of wheat pot soil

[0155]

[0156] Note: “*” indicates significant difference among treatments (p<0.05), and “**” indicates extremely significant difference among treatments (p<0.01).

[0157] Table 13 Effects of strain B8 on biological traits of wheat

[0158]

[0159] Note: “*” indicates significant difference among treatments (p<0.05), and “**” indicates extremely significant difference among treatments (p<0.01).

[0160] According to Table 12, after inoculation with Apricot B8, the soil IAA, available phosphorus, and available potassium contents were significantly increased by 81.82%, 37.86%, and 18.55% respectively compared with the CK treatment, indicating that the strain can effectively increase the nutrient content in the soil to promote the growth of wheat. According to Table 13, after inoculation with Apricot B8, the plant height, fresh weight, root surface area, and root volume of wheat seedlings were significantly increased by 10.84%, 16.39%, 21.23%, and 40.85% respectively compared with the CK treatment.

[0161] Based on the above results, it can be seen that the multifunctional rhizosphere growth-promoting bacteria Apricotibacterium avermodiosum B8 of the present invention can effectively increase the nutrient content in the soil, has a significant effect on promoting the growth and development of wheat roots, and can effectively promote the growth of wheat.

[0162] Example 7

[0163] The Apricot B8 isolated in Example 1 was prepared into a bacterial agent using bone powder as a carrier. The obtained bacterial agent contained 10 11 CFU / g, and planted food crops wheat and corn, oil-bearing crops peanuts, and cash crops tobacco at appropriate planting times for various crops, and conducted field trials to verify the efficacy of B8.

[0164] Taking tobacco as an example to illustrate the efficacy of A. aegypti B8, the economic crop tobacco was planted on April 18, 2022 in the experimental field in Luoshan County, Xinyang City, Henan Province. The altitude of the experimental field is 55.8m (N32.1924, E114.3305), the annual average temperature is 15.3℃, and the annual average precipitation is 1050mm. The basic physical and chemical properties of the soil in the experimental field are pH5.34, organic matter 14.9g / kg, total nitrogen 1.12g / kg, available phosphorus 10.22mg / kg, and available potassium 104.37mg / kg.

[0165] The experiment was repeated three times, arranged in random blocks, and the area of ​​the plot was 6×3m 2 80 tobacco trees were planted in each plot, with a row spacing of 120 cm and a plant spacing of 50 cm. All treatments were treated with 15-15-15 compound fertilizer as base fertilizer at a rate of 600 kg / hm2. 2 At the same time, 40 kg / hm2 of Apricot B8 microbial agent was applied. 2 The control treatment group was given an equal amount of bone meal, and the yield and corresponding quality indicators were measured at the harvest time. The results are shown in Tables 14 and 15.

[0166] Table 14 Effects of strain B8 on tobacco biological traits

[0167]

[0168] Note: “*” indicates significant difference among treatments (p<0.05), and “**” indicates extremely significant difference among treatments (p<0.01).

[0169] Table 15 Effect of strain B8 on chemical components of tobacco after curing

[0170]

[0171] Note: “*” indicates significant difference among treatments (p<0.05), and “**” indicates extremely significant difference among treatments (p<0.01).

[0172] According to Table 14, compared with the control, the treatment with Apricot B8 significantly increased the plant height, stem girth, and maximum leaf area of ​​tobacco by 7.23%, 3.33%, and 37.25%, indicating that the strain can increase tobacco yield in a field environment. According to Table 15, the strain can also enhance the quality of tobacco. After inoculation with Apricot B8, compared with the CK treatment, the total sugar, reducing sugar, and potassium contents of the flue-cured tobacco leaves increased significantly by 11.88%, 15.25%, and 20.86%, respectively.

[0173] It can be seen from the above embodiments that the Prioccidioides aeruginosa B8 provided by the present invention has a strong IAA production function, can also promote the dissolution of insoluble phosphorus and potassium in the soil, has a certain antagonistic effect on wheat root rot pathogens, and can significantly increase the growth rate of plants, improve crop yields and product quality.

[0174] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A strain of Priestia aryabhattai B8, characterized in that: It is deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, the deposit date is September 10, 2024, and the deposit number is CGMCC No.31932.

2. A bacterial agent, characterized in that The active ingredient of the bacterial agent includes the Prioccidioides axetinifolia B8 described in claim 1.

3. The bacterial agent according to claim 2, characterized in that The effective viable bacteria count of A. aegypti B8 in the bacterial agent is ≥1×10 11 CFU / g.

4. Use of the Apricot B8 according to claim 1 or the bacterial agent according to claim 2 or 3, characterized in that: The application includes at least one of the following 1) to 5): 1) Prevent and control wheat root rot; 2) Increase the indoleacetic acid content of plants; 3) Promote plant growth; 4) Improve soil nutrients; 5) Improve plant quality.

5. The use according to claim 4, characterized in that: The promoting plant growth comprises at least one of promoting root growth, increasing plant height and increasing leaf area.

6. The use according to claim 4 or 5, characterized in that: The plant comprises at least one of tobacco, cotton, fruit trees, Chinese cabbage, tomatoes, wheat, millet, corn and sorghum.

7. The use according to claim 4, characterized in that: Improving soil nutrients includes promoting the dissolution of sparingly soluble phosphorus and / or potassium in the soil.

8. The use according to claim 4, characterized in that: The improving of plant quality comprises increasing at least one of the content of total sugar, reducing sugar and potassium in the plant.

9. The use according to claim 4, characterized in that: The application The method comprises the following steps: applying the Afrococcus aegypti B8 described in claim 1 or the bacterial agent described in claim 2 or 3 to soil in which plants are planted.

10. The use according to claim 9, characterized in that: The amount of the microbial agent applied is 35-45 kg / hm 2 .

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