A strain of pleistopherrus asaccharolyticus and application thereof

Abstract

The present application belongs to the technical field of microorganisms, and particularly relates to a strain of Priestia aryabhattai and application thereof. The present application provides a strain of Priestia aryabhattai B8, which is preserved in the China General Microbiological Culture Collection Center on September 10, 2024, and has a preservation number of CGMCC No.31932. The Priestia aryabhattai B8 has a strong function of producing indole acetic acid, can improve the indole acetic acid content of plants, and further improve the stress resistance of plants; and can promote the dissolution of insoluble phosphorus and potassium in soil, improve soil nutrients, promote plant growth, and improve plant quality; meanwhile, the Priestia aryabhattai B8 has a certain antagonistic effect on the pathogenic bacteria of wheat root rot, and can be used for preventing and treating wheat root rot.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of microorganisms, and particularly relates to a strain of Priestia aryabhattai and application thereof. BACKGROUND

[0002] Yellow-brown soil refers to a weak Al-accumulation soil with strong acid reaction and unsaturated base under the deciduous evergreen broad-leaved forest in the north subtropics, which is subjected to strong leaching. In the utilization of yellow-brown soil, there are not only the main crops of wheat in the temperate zone, but also indica rice with the characteristics of the subtropics, and also economic crops such as tobacco. However, due to the continuous cropping obstacles, the physical and chemical properties of tobacco planting soil are deteriorated, the yield and quality of tobacco leaves are reduced, and the high-quality tobacco area is shrinking. Therefore, reducing the continuous cropping obstacles of tobacco fields in yellow-brown soil can help improve the quality and yield of tobacco leaves, maintain soil health, improve resource utilization efficiency, and promote sustainable agricultural development.

[0003] Plant growth promoting rhizobacteria (PGPR) refers to a kind of beneficial bacteria that can promote plant growth and the absorption and utilization of mineral nutrients, and can inhibit harmful organisms, which freely live in soil or are parasitic on plant roots. PGPR can synthesize substances that have a direct effect on plant growth and development, such as plant hormones, to promote plant growth, and 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 to make them available for plant absorption. However, there are few reports of multifunctional growth-promoting bacteria that have the functions of dissolving phosphorus and potassium, producing hormones and resisting diseases, and there is an urgent need for a multifunctional growth-promoting bacteria to improve soil properties. SUMMARY

[0004] The purpose of the present application is to provide a strain of Priestia aryabhattai and its application. The Priestia aryabhattai B8 has the function of producing indole acetic acid, can promote the dissolution of insoluble phosphorus and potassium in the soil, promote plant growth, improve plant quality, and has antagonistic effect on the pathogen of wheat root rot.

[0005] The present application provides a strain of Priestia aryabhattai B8, which is preserved in the China General Microbiological Culture Collection Center on September 10, 2024, and has the preservation number of CGMCC No.31932.

[0006] The present application also provides a bacterial agent, wherein the effective component of the bacterial agent comprises the Priestia aryabhattai B8 described in the above scheme.

[0007] As a preferred scheme, the effective viable bacterial number of the Priestia aryabhattai B8 in the bacterial agent is greater than or equal to 1x10 11 CFU / g.

[0008] The application also provides the application of the Plriistella asellus B8 or the microbial inoculant, and the application includes at least one of the following 1) to 5):

[0009] 1) preventing and treating wheat root rot;

[0010] 2) increasing the content of indole acetic acid in plants;

[0011] 3) promoting plant growth;

[0012] 4) increasing soil nutrients;

[0013] 5) improving plant quality.

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

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

[0016] As a preferred solution, the soil nutrient increase includes promoting the dissolution of insoluble phosphorus and / or potassium in the soil.

[0017] As a preferred solution, the plant quality improvement includes at least one of increasing the total sugar, reducing sugar and potassium content of the plant.

[0018] As a preferred solution, the application includes the following steps: applying the Plriistella asellus B8 or the microbial inoculant to the soil where the plants are planted.

[0019] As a preferred solution, the application amount of the microbial inoculant is 35 to 45 kg / hm 2 .

[0020] Advantages:

[0021] The application provides a strain of Priestia aryabhattai B8, which is preserved in the China General Microbiological Culture Collection Center on September 10, 2024, and has a preservation number of CGMCC No. 31932. The Priestia aryabhattai B8 can produce indole-3-acetic acid (IAA) with a concentration of 67.41 mg / L or more, can directly promote the elongation of the plant root system, and increase the chance of contacting nutrients in the soil; and can increase the content of endogenous IAA in the plant body, induce the expression of plant defense genes, and improve the stress resistance of the plant body, such as disease resistance and drought resistance. Moreover, the Priestia aryabhattai B8 has the ability to dissolve phosphorus, and can dissolve inorganic phosphorus with a concentration of 532.33 mg / L or more, can convert the difficult-to-utilize phosphorus into available phosphorus, and increase the content of available phosphorus in the soil. In addition, the Priestia aryabhattai B8 also has the ability to dissolve potassium, and can dissolve potassium with a solubility of 275.01 mg / L or more, can improve the utilization rate of fertilizer, and promote the growth and development of the plant and the absorption of fertilizer. Meanwhile, the Priestia aryabhattai B8 has a certain antagonistic effect on the root rot pathogen of wheat, and has the potential for biocontrol application.

[0022] The Priestia aryabhattai B8 can promote the growth of plants, and the results of the examples show that the application of the Priestia aryabhattai B8 to tobacco, small Chinese cabbage and wheat potting can promote the increase of the content of IAA and the content of nutrients in the soil, promote the root system of crops to be thicker, longer and have a larger surface area, is conducive to the absorption of water and nutrients by the root system of crops, and makes the plant height and dry weight of the aboveground part of crops significantly higher than those of the control treatment. In the tobacco field test, compared with the control, the treatment of the Priestia aryabhattai B8 makes the tobacco have higher plant height and leaf area, and promotes the increase of the yield of tobacco; the contents of total sugar and reducing sugar in the cured tobacco are 11.88% and 15.25% higher than those of the control treatment, respectively, and the potassium content in the cured tobacco leaf is 20.86% higher than that of the control treatment, and the Priestia aryabhattai B8 can improve the yield and quality of tobacco. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed in the embodiments.

[0024] Figure 1 It is a colony map of the strain B8 of the application;

[0025] Figure 2 It is a phylogenetic tree of the Priestia aryabhattai B8 of the application;

[0026] Figure 3Figure of antagonistic effect of Priestia aryabhattai B8 on wheat root rot pathogen; wherein A is an effect picture without inoculation of Priestia aryabhattai B8; and B is an effect picture with inoculation of Priestia aryabhattai B8.

[0027] Biological preservation instructions

[0028] Priestia aryabhattai B8 was preserved in the China General Microbiological Culture Collection Center (CGMCC) on September 10, 2024, with the preservation number of CGMCC No. 31932 and the strain number of B8. DETAILED DESCRIPTION

[0029] The application provides a Priestia aryabhattai B8, which is preserved in the China General Microbiological Culture Collection Center (CGMCC) on September 10, 2024, with the preservation number of CGMCC No. 31932.

[0030] The cell morphology of the Priestia aryabhattai B8 is as follows: having a capsule, no spore, single polar flagellum, being able to move, and forming a 2mm colony after being cultured on a selective medium for 24 hours; the colony morphology is that the colony is yellowish, round, the surface is convex, smooth and moist, relatively viscous, easy to pick up, and the edge is neat; and the physiological and biochemical characteristics of the Priestia aryabhattai B8 are as follows: gram-positive, facultative anaerobic, peroxidase positive, M.R test negative, and VP test negative.

[0031] In the application, the Priestia aryabhattai B8 has the abilities of secreting IAA and promoting the dissolution of insoluble phosphorus and potassium in soil; the IAA secreted by the Priestia aryabhattai B8 reaches 67.41mg / L, the inorganic phosphorus dissolution capacity reaches 532.33mg / L, and the potassium dissolution capacity reaches 275.01mg / L.

[0032] The application further provides a bacterial agent, and the effective component of the bacterial agent comprises the Priestia aryabhattai B8 described in the above scheme. 11 CFU / g. In the application, the bacterial agent comprises the Priestia aryabhattai B8 and a carrier; the type of the carrier is not specially limited in the application, and a carrier commonly used in the field can be used; in the embodiment of the application, the type of the carrier is bone powder.

[0033] The application also provides the application of the Alcaligenes faecalis B8 or the bacterial agent, and the application includes at least one of the following 1) to 5): 1) preventing and treating wheat root rot; 2) increasing the content of indole acetic acid of plants; 3) promoting the growth of plants; 4) increasing soil nutrients; and 5) improving the quality of plants.

[0034] As an embodiment, the Alcaligenes faecalis B8 has certain antagonistic effect on the pathogen of wheat root rot, and can be used for preventing and treating wheat root rot.

[0035] As an embodiment, the promotion of the growth of plants includes at least one of the promotion of the growth of roots, the increase of plant height and the increase of leaf area. As an embodiment, the plants include at least one of tobacco, cotton, fruit trees, Chinese cabbage, tomatoes, wheat, millet, corn and sorghum. The indole acetic acid produced by the Alcaligenes faecalis B8 can directly promote the growth of plant roots, so that the roots are thicker, longer and have a larger surface area, thereby increasing the contact opportunity of plants with nutrients in the soil and increasing the plant height, leaf area and dry weight of the above-ground part of plants.

[0036] As an embodiment, the increase of soil nutrients includes the promotion of the dissolution of insoluble phosphorus and / or potassium in the soil. The Alcaligenes faecalis B8 can dissolve insoluble inorganic phosphorus with a concentration of 532.33 mg / L or more, can convert the difficult-to-utilize phosphorus into available phosphorus, and increase the content of available phosphorus in the soil. In addition, the strain also has the ability to dissolve potassium, and the solubility of insoluble potassium reaches 275.01 mg / L or more, thereby increasing the utilization rate of fertilizers and promoting the growth and development of plants and the absorption of fertilizers.

[0037] As an embodiment, the improvement of the quality of plants includes at least one of the increase of the contents of total sugar, reducing sugar and potassium. In the application, the Alcaligenes faecalis B8 can increase the contents of total sugar, reducing sugar and potassium in cured tobacco, thereby increasing the yield and quality of tobacco.

[0038] As an embodiment, the application includes the following steps: applying the Alcaligenes faecalis B8 or the bacterial agent into the 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 of the field.

[0039] As an embodiment, before the application of the Pluribacter azaburghensis B8 to the soil where plants are planted, the Pluribacter azaburghensis B8 is further subjected to a large-scale culture to obtain a bacterial suspension. In the present application, the culture medium for the large-scale culture has a pH of 6-8; the culture medium for the large-scale culture comprises an inorganic salt culture medium; the inorganic salt comprises 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 comprises the following components in a mass percentage of 1000 mL: 1% of a carbon source and 0.05%-0.1% of a nitrogen source; as an embodiment, the carbon source comprises one or more of glucose, sucrose, and maltose; and the nitrogen source comprises one or more of urea, peptone, and yeast powder. The present application does not have special limitations on the sources of the carbon source, the nitrogen source, and the inorganic salt, and any sources of the carbon source, the nitrogen source, and the inorganic salt known to those skilled in the art can be used. As an embodiment, the time for the large-scale culture is 68 h. In the present application, the large-scale culture is a shaking culture, the shaking culture has a rotation speed of 180 rpm, and the medium has a filling volume of 30-70 mL / 250 mL conical flask during the shaking culture.

[0040] As an embodiment, the application amount of the Pluribacter azaburghensis B8 is 1-9 x 10 8 CFU / g of soil, and in the specific embodiments of the present application, the application amount of the Pluribacter azaburghensis B8 can be any value in the range of 1-9 x 10 8 CFU / g of soil. 2 As an embodiment, the application amount of the bacterial agent is 35-45 kg / hm 2 , and in the specific embodiments of the present application, the application amount of the bacterial agent can be any value in the range of 35-45 kg / hm 11 As an embodiment, the effective viable cell count of the Pluribacter azaburghensis B8 in the bacterial agent is 1-9 x 10 11 CFU / g, and in the specific embodiments of the present application, the effective viable cell count of the Pluribacter azaburghensis B8 in the bacterial agent can be any value in the range of 1-9 x 10

[0041] In order to further illustrate the present application, a Pluribacter azaburghensis strain and the application thereof provided by the present application are described in detail below in combination with the accompanying drawings and examples, but they should not be understood as limiting the scope of protection of the present application.

[0042] Example 1

[0043] (1) Preparation of experimental culture medium

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

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

[0046] Liquid potassium-lysing bacterial 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, potassium feldspar powder 1.0 g and distilled water 1000 mL, sterilized at 121°C for 20 min.

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

[0048] (2) Isolation of bacteria

[0049] A, 10 g of natural condition tobacco planting soil was collected from Luoshan County, Xinyang City, Henan Province, and the soil was yellow-brown soil, and the basic physicochemical properties were shown in Table 1. B, the soil collected in step A was placed in a 250 mL triangular flask containing 100 mL of sterilized water, and was shaken in a shaking bed at 30°C and 150 rpm for 20 min, and was left for 10 min to obtain a soil bacterial suspension. C, the soil bacterial suspension obtained in step B contained several kinds of plant growth promoting bacteria, which were diluted by dilution method and then coated on LB medium, and the plate was inverted and cultured in a thermostat at 30°C for 24 h, and then different types of typical single colonies were picked and purified by plate, and were stored at 4°C on LB slant, and seed liquid with OD 600 1 was prepared for use, and plant growth promoting bacteria capable of secreting indole acetic acid were screened by qualitative determination and quantitative determination.

[0050] Table 1 Basic physicochemical properties of test soil

[0051]

[0052] (3) Qualitative determination

[0053] A, the bacteria separated and purified in step (2) were inoculated into LB liquid medium containing L-tryptophan (100 mg / L) at an inoculation amount of 1%, and cultured at 30°C for 1 day on a 180 rpm shaker. B, after the culture, 50 μL of bacterial suspension in step A was dropped on a white ceramic plate, and 50 μL of Salkowski colorimetric solution (50 mL of 35% (w / v) HCIO4+ 1 mL of 0.5 M FeCl3) was added. C, the positive control group was: 50 μL of 50 mg / L indole acetic acid and 50 μL of Salkowski colorimetric solution were dropped on a white ceramic plate. D, the white ceramic plate was observed after being placed at room temperature for 30 min in the dark, and those with red color indicated that they could secrete indole acetic acid.

[0054] (4) Quantitative determination

[0055] A, the bacteria separated and purified in step (2) were inoculated into LB liquid medium containing L-tryptophan (100 mg / L) at an inoculation amount of 1%, and cultured at 30°C for 1 day on a 180 rpm shaker. B, after the culture, 50 μL of bacterial suspension in step A was dropped on a white ceramic plate, and 50 μL of Salkowski colorimetric solution (50 mL of 35% (w / v) HCIO4+ 1 mL of 0.5 M FeCl3) was added. C, the positive control group was: 50 μL of 50 mg / L indole acetic acid and 50 μL of Salkowski colorimetric solution were dropped on a white ceramic plate. D, the white ceramic plate was observed after being placed at room temperature for 30 min in the dark, and those with red color indicated that they could secrete indole acetic acid. 530 A, the bacteria separated and purified in step (2) were inoculated into LB liquid medium containing L-tryptophan (100 mg / L) at an inoculation amount of 1%, and cultured at 30°C for 1 day on a 180 rpm shaker. B, after the culture, 50 μL of bacterial suspension in step A was dropped on a white ceramic plate, and 50 μL of Salkowski colorimetric solution (50 mL of 35% (w / v) HCIO4+ 1 mL of 0.5 M FeCl3) was added. C, the positive control group was: 50 μL of 50 mg / L indole acetic acid and 50 μL of Salkowski colorimetric solution were dropped on a white ceramic plate. D, the white ceramic plate was observed after being placed at room temperature for 30 min in the dark, and those with red color indicated that they could secrete indole acetic acid.

[0056] (5) Screening of the bacteria with better IAA production for determination of their phosphate-solubilizing and potassium-solubilizing abilities

[0057] A, the bacteria separated and purified in step (2) were inoculated into LB liquid medium containing L-tryptophan (100 mg / L) at an inoculation amount of 1%, and cultured at 30°C for 1 day on a 180 rpm shaker. B, after the culture, 50 μL of bacterial suspension in step A was dropped on a white ceramic plate, and 50 μL of Salkowski colorimetric solution (50 mL of 35% (w / v) HCIO4+ 1 mL of 0.5 M FeCl3) was added. C, the positive control group was: 50 μL of 50 mg / L indole acetic acid and 50 μL of Salkowski colorimetric solution were dropped on a white ceramic plate. D, the white ceramic plate was observed after being placed at room temperature for 30 min in the dark, and those with red color indicated that they could secrete indole acetic acid.

[0058] (6) Screening of the bacteria with better IAA production for determination of their potassium-solubilizing abilities

[0059] A, the bacteria separated and purified in step (2) were inoculated into LB liquid medium containing L-tryptophan (100 mg / L) at an inoculation amount of 1%, and cultured at 30°C for 1 day on a 180 rpm shaker. B, after the culture, 50 μL of bacterial suspension in step A was dropped on a white ceramic plate, and 50 μL of Salkowski colorimetric solution (50 mL of 35% (w / v) HCIO4+ 1 mL of 0.5 M FeCl3) was added. C, the positive control group was: 50 μL of 50 mg / L indole acetic acid and 50 μL of Salkowski colorimetric solution were dropped on a white ceramic plate. D, the white ceramic plate was observed after being placed at room temperature for 30 min in the dark, and those with red color indicated that they could secrete indole acetic acid.

[0060] The high-yield indole acetic acid, strong phosphorus-dissolving and potassium-dissolving ability strain B8 was screened by the above determination, and the colony map is shown in Figure 1 .

[0061] Table 2: The growth-promoting ability of strain B8

[0062] Tested strains IAA production ability (mg / L) Inorganic phosphorus solubilizing ability (mg / L) Potassium solubilizing ability (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 has the ability to dissolve inorganic phosphorus, reaching 532.33 mg / L; and has the ability to dissolve potassium, reaching 275.01 mg / L.

[0064] (7) Aerobic test

[0065] The sterilized LB medium was poured into three sterilized test tubes, about 2 / 3, and the strain B8 on the slant was picked up with an inoculation needle on a sterile operation table and inoculated into the above-mentioned medium by puncture (must puncture to the bottom of the tube). The results were observed at 30°C for 3-7 days.

[0066] The growth on the surface of the agar column is aerobic bacteria, and the growth along the puncture line is anaerobic or facultative anaerobic bacteria. The test results show that the strain B8 colony grows along the surface of the agar column, and the colony also grows in the puncture line, which is facultative anaerobic.

[0067] (8) Catalase determination

[0068] One drop of 3% H2O2 was dropped on a clean glass slide, and one loop of the strain B8 culture on the LB slant for 18-24 h was taken with an inoculation loop and smeared 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 the strain B8 is catalase positive.

[0069] (9) Methyl red test (M.R test)

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

[0071] B, strain culture and result observation: inoculate the strain B8 in the above-mentioned culture solution and culture at 30°C for 1-2 days. Add a few drops of methyl red reagent to the culture solution. If the culture solution presents red color, it is methyl red positive, and yellow color is negative (methyl red color change range 4.4 red-6.0 yellow). The test results are shown in Table 3, and the results show that the strain B8 is methyl red negative.

[0072] (10) Ethylmethylmethanol test (VP test)

[0073] A. Medium preparation: The same as step (9) methyl red test.

[0074] B. Strain culture and result observation: Inoculate and culture the same as step (9) methyl red test. When VP test is done, mix the culture solution (about 2 mL) with equal amount of 40% NaOH, add a little creatine, shake well for 2-5 min. If the culture solution appears red, it is VP positive. The test result is shown in Table 3, which shows that strain B8 is VP negative.

[0075] (11) Starch hydrolysis test

[0076] A. ① Medium preparation: Add 0.2% soluble starch to the broth peptone agar, distribute into triangular flasks, sterilize at 121°C for 20 min for standby. ② Lugol's iodine solution: iodine tablet 1 g, potassium iodide 2 g, first dissolve the potassium iodide with a small amount (3-5 mL) of distilled water, then add iodine tablet, after the iodine is completely dissolved, dilute with water to 300 mL.

[0077] B. Strain culture and result observation: Take strain B8 and inoculate on the plate, culture at 30°C for 2-4 days, after colonies are formed, add Lugol's iodine solution on the plate, until the colonies are covered, the plate appears blue, if there is a colorless transparent circle around the colonies, it means that starch has been hydrolyzed. The size of the transparent circle generally indicates the size of the starch hydrolysis ability. The test result is shown in Table 3, which shows that strain B8 is starch hydrolysis positive.

[0078] (12) Gelatin hydrolysis test

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

[0080] B. Strain culture and result observation: inoculate strain B8 in the center of the test tube by puncture method, culture in a 30°C incubator for one month, observe whether the gelatin is liquefied. The test result is shown in Table 3, which shows that strain B8 is gelatin hydrolysis positive.

[0081] (13) Nitrate reduction test

[0082] A, ① Nitrate liquid medium configuration: Proteose peptone 10 g, potassium nitrate 1 g and distilled water 1000 mL, pH 7.0-7.4. ② Gries reagent: A liquid: p-aminobenzoic acid 0.5 g, dilute acetic acid (about 10%) 150 mL; B liquid: thiamine 0.1 g, distilled water 20 mL, dilute acetic acid (about 10%) 150 mL. ③ Diphenylamine reagent: diphenylamine 0.5 g is dissolved in 100 mL concentrated sulfuric acid, diluted with 20 mL distilled water.

[0083] B, Strain culture and result observation: the strain B8 is inoculated in nitrate liquid medium, and cultured at 30°C for 1, 3, 5 days. A little culture solution is poured into a small hole of white porcelain tray, and then 1 drop of reagent A and B liquid is dropped in it respectively. When the culture solution becomes pink, rose red, orange or brown, etc., it indicates that nitrite exists, and it is nitrate reduction positive, otherwise it is negative. The test results are shown in Table 3, and the results show that the strain B8 is nitrate reduction positive.

[0084] (14) Citrate utilization

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

[0086] B, Strain culture and result observation: fresh B8 strain is inoculated on slant, and cultured at 30°C for 3-7 days. The culture medium is alkaline (blue) for positive reaction, and unchanged for negative reaction. The test results are shown in Table 3, and the results show that the strain B8 is positive.

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

[0088] Item Result Item Result Gram stain + Starch hydrolysis + Aerobic test Facultative anaerobic Gelatin liquefaction + Contact enzyme test + Nitrate reduction + Methyl red (M.R) reaction - Citrate utilization + V-P test - / /

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

[0090] The strain B8 screened and separated by the above method is sequenced by Shanghai Yingjun Biological Engineering Co., Ltd. According to the sequencing results of 16S rDNA, online query and analysis are carried out at http: / / www.ncbi.nlm.nih.gov, homology comparison is carried out with other 16S rDNA sequences in GenBank by using Blast software, similar sequences and the sequence of strain B8 are selected to construct the 16S rDNA phylogenetic tree of strain B8 by using MEGA version 3 software, as shown in Figure 1. Figure 2The sequence information of the 16S rDNA of the strain B8 is shown as SEQ ID NO. 1. According to the physiological and biochemical characteristics of the strain, it is identified as Priestia aryabhattai, and the strain is preserved in the China General Microbiological Culture Collection Center on September 10, 2024, with the preservation number of CGMCC No. 31932.

[0091] The cell morphology of the strain B8 is as follows: having a capsule, no spore, unipolar flagellum, being able to move, and forming a 2mm colony after being cultured on a selective medium for 24h; the colony morphology is that the colony is yellowish, round, the surface is convex, smooth and moist, relatively viscous, easy to pick up, and the edge is neat; the physiological and biochemical characteristics of the strain B8 are as follows: gram-positive, facultative anaerobic, hydrogen peroxide enzyme positive, M.R test negative, and VP test negative.

[0092] Example 2

[0093] (1) To further verify the ability of the plant growth-promoting bacterium Priestia aryabhattai B8 to produce indole acetic acid and the optimal conditions, the effects of different pH, liquid loading amount, different carbon sources and different nitrogen sources on the production of indole acetic acid were explored.

[0094] Orthogonal test was performed on four factors of carbon source, nitrogen source, pH and liquid loading amount, and each factor level was set as shown in Table 4, and the inorganic salt medium containing L-tryptophan 100mg / L was adjusted. Among them, the carbon and nitrogen sources were added in an amount of 1% and 0.1% (M / V) respectively, the selected strain was inoculated in a 250mL triangular flask, and was cultured at 30℃, 180rpm for 1d, and the amount of IAA produced was determined by Salkowski colorimetry, and the results are shown in Table 5.

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

[0096] Different conditions Carbon source Nitrogen source pH Liquid volume (mL / 250 mL) 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 the IAA production capacity of strain B8

[0098]

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

[0100] According to Table 5, the influence of each factor on the IAA production capacity of strain B8 is in the order of liquid loading amount>carbon source>pH>nitrogen source, and the optimal condition combination for B8 to produce IAA is that the carbon source is maltose, the nitrogen source is peptone, the pH is 7, and the liquid loading amount is 70mL / 250mL.

[0101] (2) To further verify the ability of rhizosphere growth-promoting bacteria B8 to dissolve inorganic phosphorus and the optimal conditions, the effects of different pH, liquid loading, different carbon sources, and different nitrogen sources on the ability to dissolve inorganic phosphorus were explored.

[0102] Orthogonal tests were conducted on four factors, i.e., carbon source, nitrogen source, pH, and liquid loading, and the levels of each factor were set as shown in Table 4. The inorganic phosphorus bacterial culture medium was adjusted accordingly. The selected strains were inoculated in 250 mL triangular bottles, and cultured at 30°C and 180 rpm for 3 days. The supernatant phosphorus content was determined by the molybdenum blue colorimetric method, and the results are shown in Table 6.

[0103] Table 6 Results of orthogonal test of strain B8 for dissolving inorganic phosphorus

[0104]

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

[0106] According to Table 6, the factors affecting the ability of strain B8 to dissolve inorganic phosphorus in descending order are pH, liquid loading, nitrogen source, and carbon source. Based on the average values of the four factors and the intuitive analysis comparison, the optimal combination of the ability of strain B8 to dissolve inorganic phosphorus is carbon source of glucose, nitrogen source of urea, pH of 7, and liquid loading of 50 mL / 250 mL.

[0107] (3) To further verify the optimal conditions of rhizosphere growth-promoting bacteria B8 for dissolving potassium, the effects of different pH, liquid loading, different carbon sources, and different nitrogen sources on the production of indole acetic acid were explored.

[0108] Orthogonal tests were conducted on four factors, i.e., carbon source, nitrogen source, pH, and liquid loading, and the levels of each factor were set as shown in Table 4. The inorganic phosphorus bacterial culture medium was adjusted accordingly. The selected strains were inoculated in 250 mL triangular bottles, and cultured at 30°C and 180 rpm for 3 days. The supernatant phosphorus content was determined by the molybdenum blue colorimetric method, and the results are shown in Table 6.

[0109] Table 7 Results of orthogonal test of strain B8 for dissolving potassium

[0110]

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

[0112] According to Table 7, the influence of each factor on the potassium- releasing ability of strain B8 is in the order of carbon source > nitrogen source > liquid volume > pH. By comparing the average values of the four factors and intuitive analysis, the optimal combination of strain B8 for potassium-releasing ability is as follows: carbon source is maltose, nitrogen source is peptone, pH is 8, and liquid volume is 50 mL / 250 mL.

[0113] Example 3

[0114] To explore the biocontrol ability of strain B8, the pathogens of wheat root rot, bitter gourd wilt, apple rot, and tobacco black shank were used as test pathogens to explore the antagonistic function of strain B8.

[0115] The plate confrontation method was used to detect the antagonistic activity of strain B8 after isolation and purification, with the pathogen as the target. The pathogen cake was placed at the center of the OA plate, and the strain was inoculated around the pathogen cake. Three replicates were set, and the pathogen cake alone was used as a control. The culture was incubated at 28℃, and the antagonistic ability was determined according to whether there was an inhibition zone.

[0116] The results showed that strain B8 had good antagonistic ability against the pathogen of wheat root rot. The pathogen of wheat root rot grew well in the OA medium without inoculation of strain B8 (Fig. 8A), while a clear inhibition zone appeared around strain B8 in the medium inoculated with strain B8 (Fig. 8B). Figure 3 Figure 3

[0117] Example 4

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

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

[0120] (3) Seed treatment: The tobacco seeds were surface sterilized with 20% hydrogen peroxide for 20 min, washed with sterile water several times, and germinated for 2 days. The tobacco seedlings with consistent germination were inoculated into the soil of the experimental group and the control group in step (2).

[0121] (4) Experimental group: The bacterial suspension of step (1) was inoculated into the soil at a dose of 10 8 CFU / g soil 24 h before transplanting the seedlings (i.e., 10​​8 CFU / g of P. alli B8).

[0122] Control group: As a control, the soil is not sprayed with B8 bacterial solution, and the same amount of sterile water is added.

[0123] Each treatment has 4 repetitions, and the pots are placed in a light culture room. After 30 days, sampling is performed, and the soil IAA content is determined by HPLC method, and the soil pH, organic matter, alkali-hydrolyzable nitrogen, available phosphorus, available potassium content, plant fresh weight, plant height, and total nitrogen, total phosphorus, and total potassium content are determined. The results are shown in Tables 8 and 9.

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

[0125]

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

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

[0128]

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

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

[0131] In summary, the multifunctional rhizosphere growth-promoting bacteria P. alli B8 of the present application can effectively increase the soil nutrient content and has obvious 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: According to the operation of step (1) in Example 4, P. alli B8 bacterial suspension is prepared.

[0134] (2) Preparation of test soil: according to the operation of step (2) in Example 4, collect the soil and randomly divide it into the experimental group (B8) and the control group (CK).

[0135] (3) Seed treatment: use 20% hydrogen peroxide to surface sterilize the pakchoi seeds for 20 min, rinse with sterile water multiple times, and germinate for 2 d; select the pakchoi seedlings with consistent germination and inoculate them in the soil of the experimental group and the control group of step (2).

[0136] (4) Experimental group: inoculate the bacterial suspension of step (1) at a dosage of 10 8 CFU / g of soil into the soil 24 h before transplanting the seedlings (i.e., inoculate 10 8 CFU / g of B8 into each gram of dry soil).

[0137] Control group: as a control, do not spray the soil with B8 bacterial solution, and add an equal amount of sterile water.

[0138] Each treatment has 4 replicates, and the pots are placed in an illumination culture room. After 30 days, sample and determine the soil IAA content by HPLC method, and determine the soil available phosphorus, available potassium content, plant fresh weight, plant height, and total nitrogen, total phosphorus, and total potassium content. The results are shown in Tables 10 and 11.

[0139] Table 10 Influence of strain B8 on the physicochemical properties of the pakchoi potting soil

[0140]

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

[0142] Table 11 Influence of strain B8 on the biological characteristics of pakchoi

[0143]

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

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

[0146] In summary, the multifunctional PGPR P. alcaliphilus B8 can effectively improve the soil nutrient content, and has obvious effect on promoting the growth and development of Chinese cabbage root system, and can effectively promote the growth of Chinese cabbage.

[0147] Example 6

[0148] (1) Preparation of bacterial suspension: according to the operation of step (1) in example 4, prepare the bacterial suspension of P. alcaliphilus B8.

[0149] (2) Preparation of test soil: according to the operation of step (2) in example 4, collect soil and randomly divide it into experimental group (B8) and control group (CK).

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

[0151] (4) Experimental group: inoculate the bacterial suspension of step (1) into the soil according to the inoculation amount of 10 8 CFU / g soil 24h before transplanting seedlings (i.e. inoculate 10 8 CFU / g P. alcaliphilus B8 per gram of dry soil).

[0152] Control group: as a control, do not spray B8 bacterial solution to the soil, and add the same amount of sterile water.

[0153] Each treatment has 4 replicates, and the pots are placed in the light culture room. After 30 days, sample and use HPLC method to determine the soil IAA content, and determine the soil available phosphorus, available potassium content, plant fresh weight, plant height and total nitrogen, total phosphorus and total potassium content. The results are shown in Tables 12 and 13.

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

[0155]

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

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

[0158]

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

[0160] According to Table 12, after inoculation of B8, the contents of IAA, available phosphorus and available potassium in the soil are 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 of B8, the plant height, fresh weight, root surface area and root volume of wheat seedlings are significantly increased by 10.84%, 16.39%, 21.23% and 40.85% respectively compared with the CK treatment.

[0161] According to the above results, it can be seen that the multifunctional rhizosphere growth-promoting bacteria B8 of the application can effectively increase the soil nutrient content and has obvious effect on promoting the growth and development of wheat root system, and can effectively promote the growth of wheat.

[0162] Example 7

[0163] The B8 of B. allii isolated in Example 1 is made into a microbial agent with bone powder as a carrier, and the obtained microbial agent contains 10 11 CFU / g of effective viable bacteria, and is respectively planted in various crops at the appropriate planting time of crops such as wheat and corn, peanut, tobacco, and the like, to verify the efficacy of B8 through field tests.

[0164] Tobacco is taken as an example to illustrate the efficacy of B8. In a test field in Luoshan County, Xinyang City, Henan Province, economic crop tobacco is planted on April 18, 2022. The test field is located at an altitude of 55.8 m (N32.1924, E114.3305), and has an average annual temperature of 15.3℃ and an average annual precipitation of 1050 mm. The basic physicochemical properties of the soil in the test field are pH 5.34, organic matter 14.9 g / kg, total nitrogen 1.12 g / kg, available phosphorus 10.22 mg / kg and available potassium 104.37 mg / kg.

[0165] The test is arranged in 3 repetitions, and the random block arrangement is used, and the area of each plot is 6x3 m 2 , 80 tobacco plants are planted in each plot, the row spacing is 120 cm, and the plant spacing is 50 cm. All treatments are applied with 15-15-15 compound fertilizer as base fertilizer, and the application amount is 600 kg / hm 2 , and B. allii B8 microbial agent is applied at the same time, and the application amount is 40 kg / hm 2 . The control group is applied with the same amount of bone powder, and the yield and corresponding quality indexes are measured at the harvest period, and the results are shown in Tables 14 and 15.

[0166] Table 14 Effect of B8 on the biological characteristics of tobacco

[0167]

[0168] Note: "*" indicates significant difference between treatments (p<0.05), "**" indicates extremely significant difference between treatments (p<0.01).

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

[0170]

[0171] Note: "*" indicates significant difference between treatments (p<0.05), "**" indicates extremely significant difference between treatments (p<0.01).

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

[0173] From the above examples, it can be seen that the Agaricicoccus sp. B8 provided by the present application has strong IAA production function, can also produce dissolved phosphorus and potassium in soil, has certain antagonistic effect on the pathogen of wheat root rot, and can significantly improve the growth rate of plants, increase the yield of crops and the quality of products.

[0174] Although the above examples have made a detailed description of the present application, it is only a part of the embodiments of the present application, but not all the embodiments, and people can also obtain other embodiments according to the present embodiments without creativity, and these embodiments all belong to the protection scope of the present application.

Claims

1. A strain of Prtus ahi (P. ahi) B8, characterized in that, Priestia aryabhattai ) B8, characterized in that, The deposit was made at the China General Microbiological Culture Collection Center on September 10, 2024, and the deposit number is CGMCC No. 31932.

2. An inoculant characterized in that, The effective component of the microbial agent includes the Priestia aryabhattai B8 of claim 1.

3. The bacterial agent of claim 2, wherein The effective viable cell number of Pristinamycetin B8 in the bacterial agent is ≥1×10 11 CFU / g.

4. Use of A. istrabilis B8 according to claim 1 or of the bacterial agent according to claim 2 or 3, characterized in that The applications include: 1) preventing and treating wheat root rot; 2) increasing the content of indole acetic acid in soil; 3) promoting plant growth; 4) increasing soil nutrients; the increasing soil nutrients include promoting the dissolution of insoluble inorganic phosphorus and potassium in soil; 5) improving tobacco quality; the improving tobacco quality includes at least one of increasing the content of total sugar, reducing sugar and potassium in tobacco; The plants include at least one of tobacco, cotton, fruit trees, Chinese cabbage, tomatoes, wheat, millet, corn and sorghum.

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

6. Use according to claim 4, characterized in that, The applications include the following steps: applying the Priestia aryabhattai B8 of claim 1 or the microbial agent of claim 2 or 3 into the soil where plants are planted.

7. Use according to claim 6, characterized in that, The application amount of the bacterial agent is 35-45 kg / hm 2 .

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