A new type of Paenibacillus SN-8-1 and its application

Abstract

The present invention discloses a novel Paenibacillus sp. SN‑8‑1 and its application, and relates to the field of microbial technology. The novel Paenibacillus sp. SN‑8‑1 disclosed in the present invention is classified and named Paenibacillus sp. SN‑8‑1, which has been deposited in the China Microbial Culture Collection Center, with a deposit number of CGMCCNO.1.60135, a deposit date of January 16, 2024, and a deposit address of: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing. The novel Paenibacillus sp. SN‑8‑1 of the present application effectively promotes the increase of soybean plant height, the increase of fresh weight of the above-ground part of soybean, and the increase of fresh weight of the underground part of soybean; secretes organic acids and phosphatases; and can effectively dissolve insoluble inorganic phosphorus. It is used to solve the problem of low phosphorus utilization efficiency in agricultural and forestry land, and has good application and promotion value.

Description

Technical Field

[0001] The present invention belongs to the field of microbial technology, and more specifically, relates to a novel strain of Paenibacillus SN-8-1 and application thereof. Background Art

[0002] Phosphorus is usually abundant in the soil, with an average soil phosphorus content of about 0.05%, but the content of effective phosphorus that can be absorbed and utilized by plants is very low, accounting for only 0.1% of the total phosphorus. According to the second national soil census, when the content of available phosphorus in moderately alkaline soil is lower than 5 mg / kg and in acidic soil is lower than 16 mg / kg, the soil is in a phosphorus-deficient state. Relevant statistics show that about 43% of the world's cultivated land lacks effective phosphorus that can be directly absorbed and utilized by plants, and cultivated land in my country that lacks effective phosphorus accounts for more than 70% of the total cultivated land in my country. Applying phosphate fertilizer can effectively increase the phosphorus content in the soil, but most of the phosphorus is incompatible with Ca in the soil. 2+ , Fe 3+ , Fe 2+ 、Al 3+ The combination of phosphate and phosphorus forms insoluble phosphates, which are difficult to be directly absorbed and utilized by plants. In addition, at the current mining rate, the global phosphate reserves will be exhausted within 50-100 years. Therefore, it is of great significance to study management strategies that can improve the efficiency of phosphorus fertilization and reduce environmental pollution caused by soil phosphorus loss.

[0003] Studies have found that there are a large number of microorganisms with phosphorus-dissolving ability in the soil. These microorganisms convert the insoluble phosphates in the soil into soluble phosphorus that can be absorbed and utilized by plants through their own metabolism. These microorganisms mainly include bacteria, fungi, actinomycetes, etc. Phosphate-dissolving bacteria can convert insoluble phosphates into a form that can be absorbed and utilized by plants, thereby directly promoting plant growth. Therefore, the development and application of microbial fertilizers is of great significance. Summary of the invention

[0004] In view of the above problems existing in the prior art, the technical problem to be solved by the present invention is to provide a novel strain of Paenibacillus SN-8-1 for effectively degrading poorly soluble inorganic phosphorus represented by calcium phosphate. Another technical problem to be solved by the present invention is to provide an application of a novel strain of Paenibacillus SN-8-1 for improving the utilization efficiency of phosphorus in agricultural and forestry land.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] A new type of Bacillus sp. SN-8-1, classified and named Paenibacillus sp. SN-8-1, has been deposited in the China Microbiological Culture Collection Center with the deposit number: CGMCC NO.1.60135, the deposit date: January 16, 2024, and the deposit address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing.

[0007] Application of the new Paenibacillus SN-8-1 in promoting soybean growth.

[0008] The method of promoting soybean growth includes promoting the increase of soybean plant height, promoting the increase of fresh weight of the above-ground part of soybean, and promoting the increase of fresh weight of the underground part of soybean.

[0009] Application of the novel Paenibacillus SN-8-1 in secretion of organic acids.

[0010] The organic acids are oxalic acid, fumaric acid, malic acid, lactic acid, acetic acid, citric acid and succinic acid.

[0011] Application of the novel Paenibacillus SN-8-1 in secretion of phosphatases.

[0012] The phosphatase is alkaline phosphatase and acid phosphatase.

[0013] Application of the new Paenibacillus SN-8-1 in solubilizing poorly soluble inorganic phosphorus.

[0014] Application of the new Bacillus SN-8-1 in improving soil fertility.

[0015] The improving soil fertility is to promote the increase of the effective phosphorus content in the soil.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1) The novel Paenibacillus sp. SN-8-1 disclosed in the present invention is classified and named Paenibacillus sp. SN-8-1, which has been deposited in the China Microbiological Culture Collection Center with a deposit number of CGMCCNO.1.60135, a deposit date of January 16, 2024, and a deposit address of Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing.

[0018] 2) The effects of different carbon sources on the solubility of the strain SN-8-1 of the present application are as follows: glucose>starch>maltose>sucrose>mannitol. When glucose was used as the carbon source, the soluble phosphorus content in the culture medium inoculated with strain SN-8-1 was the highest (361.06 mg / L), followed by starch and maltose. When mannitol was used as the carbon source, it did not have the ability to solubilize phosphorus. In short, glucose is the best carbon source for the phosphorus-dissolving bacteria SN-8-1 to release effective P. In addition, the pH measurement results showed that, except for sucrose, the lower the final pH value, the higher the P release capacity in the liquid culture medium under different carbon source culture conditions.

[0019] 3) The effects of different nitrogen sources on the solubility of the strain SN-8-1 of the present application are as follows: ammonium chloride > ammonium sulfate > peptone > potassium nitrate > sodium nitrate. The most suitable nitrogen source is ammonium chloride. After 5 days of cultivation, the soluble phosphorus content of the strain reached 365.86 mg / L. In addition, NH4 + -N as a nitrogen source has a significantly better phosphorus dissolution effect than NO3 - -N, in this application, when NaNO3 was used as the sole nitrogen source, the soluble phosphorus concentration of SN-8-1 was the lowest (78.80 mg / L). Interestingly, the pH value in the culture supernatant was opposite to the soluble phosphorus concentration measured under different nitrogen source culture conditions, that is, when ammonium chloride was used as the nitrogen source, the pH value of the liquid culture medium was the lowest.

[0020] 4) The effects of different phosphorus sources on the solubility of the strain SN-8-1 of the present application are as follows: calcium phosphate > aluminum phosphate > iron phosphate. The most suitable phosphorus source is calcium phosphate, and the soluble phosphorus content of the strain reaches 310.10 mg / L after 5 days of cultivation.

[0021] 5) The effect of environmental pH on the P solubility of strain SN-8-1 was further verified by adjusting the original pH of the liquid culture medium (4-9). The results showed that the soluble phosphorus concentration in the culture supernatant reached a peak value (608.25 mg / L) at a pH of 4. When the original pH was raised to 9, the soluble phosphorus content reached a minimum level of 341.36 mg / L, indicating that pH had a significant effect on the phosphorus solubility of strain SN-8-1. Strain SN-8-1 is more suitable for growth in an acidic environment to improve soil phosphorus utilization.

[0022] 6) The effect of ambient temperature on the phosphorus solubility of strain SN-8-1 was further verified by adjusting the shaking incubation temperature (20, 25, 30, 35, 40°C). The results showed that the soluble phosphorus concentration in the culture supernatant reached a peak value (337.27 mg / L) at a temperature of 25°C. When the culture temperature was 20°C, the soluble phosphorus content reached the lowest level of 297.15 mg / L, indicating that the culture temperature had a significant effect on the phosphorus solubility of strain SN-8-1.

[0023] 7) Seven organic acids were detected in the culture supernatant of the strain SN-8-1 of the present application, including oxalic acid, fumaric acid, malic acid, lactic acid, acetic acid, citric acid and succinic acid. Among these organic acids, malic acid was secreted the most and played a leading role in the P dissolution process.

[0024] 8) The acid phosphatase produced by the strain SN-8-1 of the present application first increased and then decreased with the change of time, and reached a maximum value of 10.46 μmol / (L·h) on the third day. The alkaline phosphatase produced by SN-8-1 continued to increase with the change of time, reaching a maximum value of 18.76 μmol / (L·h) on the fifth day. On the 1st, 2nd and 3rd days, the acid phosphatase activity secreted by the strain SN-8-1 was higher than that of the alkaline phosphatase, and the alkaline phosphatase activity was higher than that of the acid phosphatase in the middle and late stages of the culture.

[0025] 9) The soybean plants inoculated with SN-8-1 in this application grow more luxuriantly and have well-developed root systems. The height of soybean plants inoculated with SN-8-1 is 41.49±0.87cm, which is significantly higher than the height of control plants. After inoculation with strain SN-8-1, the fresh weight of the aboveground part of soybean plants increased by 13.16% compared with the control group, and the application of SN-8-1 significantly increased the fresh weight of the aboveground part of the plants. The fresh weight of the underground part of soybeans inoculated with SN-8-1 was 0.48±0.01g, which was significantly higher than the fresh weight of the underground part of the control soybeans. The above results show that the application of SN-8-1 can significantly promote the growth of soybean plants. The available phosphorus content in the soil inoculated with SN-8-1 was 13.21mg / kg, an increase of 44.21% over the control group. The above results show that the available phosphorus content in the soil increased significantly after inoculation with SN-8-1. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The colony images of strain SN-8-1 on R2A and phosphate-soluble medium (30°C, 2 days);

[0027] Figure 2 This is the bacterial morphology of strain SN-8-1 under field emission scanning electron microscope;

[0028] Figure 3 Phylogenetic tree constructed for the 16S sequence of strain SN-8-1;

[0029] Figure 4 Figure 2 is the phosphorus solubilization ability of strain SN-8-1 under different culture conditions (different carbon sources (A), nitrogen sources (B), phosphorus sources (C), original pH values ​​(D) and temperatures (E));

[0030] Figure 5This is a graph for determining the content of organic acids secreted by strain SN-8-1 (different capital letters in the figure indicate significant differences in the content of the same organic acid at different culture times (P<0.05); different lowercase letters indicate significant differences in the content of different organic acids at the same culture time (P<0.05));

[0031] Figure 6 This is a graph for determining the phosphatase content produced by strain SN-8-1;

[0032] Figure 7 The growth phenotype of soybeans inoculated and not inoculated with Bacillus sp. (SN-8-1) (the concentration of the applied bacterial solution was 10 8 cfu / mL, CK is the uninoculated control, scale bar is 20 cm);

[0033] Figure 8 This is a chart showing the determination of available phosphorus content in potted soil in a soybean growth promotion experiment. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described below in conjunction with specific embodiments. Unless otherwise specified in the following embodiments, the technical means used are conventional means well known to those skilled in the art.

[0035] R2A culture medium and other chemical reagents or instruments and equipment, unless otherwise specified, are conventional reagents or instruments and equipment, and can be purchased through commercial channels. Unless otherwise specified, the quantitative tests in the following examples are set up for three repeated experiments, and the results are averaged.

[0036] The formula of inorganic phosphorus solid culture medium is: glucose 10g, ammonium sulfate 0.5g, sodium chloride 3g, potassium chloride 0.3g, magnesium sulfate 0.3g, ferrous sulfate 0.03g, manganese sulfate 0.03g, yeast extract 0.4g, calcium phosphate 5g, agar 18g, deionized water 1L, sterilized at 121℃ for 15min. Unless otherwise specified, the pH is 7.0.

[0037] The formula of inorganic phosphorus liquid culture medium is: glucose 10g, ammonium sulfate 0.5g, sodium chloride 3g, potassium chloride 0.3g, magnesium sulfate 0.3g, ferrous sulfate 0.03g, manganese sulfate 0.03g, yeast extract 0.4g, calcium phosphate 5g, deionized water 1L, sterilized at 121℃ for 15min. Unless otherwise specified, the pH is 7.0.

[0038] Example 1

[0039] 1. Strain Isolation

[0040] The soybean rhizosphere soil was collected, and the suspension was shaken thoroughly with sterile water. -6The gradient dilution was applied to the inorganic phosphorus solid culture medium and placed in a 30°C incubator for culture. Then the bacterial colonies with transparent circles on the culture medium were picked out and inoculated on a new inorganic phosphorus solid culture medium for culture. The cultured bacteria were made into bacterial liquids and inoculated into inorganic phosphorus liquid culture medium for culture. By measuring the content of soluble phosphorus in the bacterial liquid, the phosphate-dissolving bacteria SN-8-1 with better effect was screened out.

[0041] 2. Strain identification and preservation

[0042] 1) Colony characteristics analysis

[0043] The screened phosphate-dissolving bacteria SN-8-1 was inoculated into R2A medium, and then the plate was inverted and cultured at 30°C for 2-3 days, and the growth of the colonies on the plate was observed and recorded.

[0044] The results are as follows Figure 1 As shown, the colonies are milky white, round, convex and opaque.

[0045] 2) Microscopic morphological characteristics analysis

[0046] After the strains were grown on R2A medium for 3 days, the shape and structure of bacterial cells were observed using a transmission electron microscope. The samples needed to be freeze-dried before observation.

[0047] The results are as follows Figure 2 As shown, the bacteria of strain SN-8-1 were observed to be long rod-shaped by transmission electron microscopy.

[0048] 3) 16S sequence analysis

[0049] The DNA in this strain was extracted by traditional methods. Among them, the 30μL PCR reaction system included 1μL template primer, 1μL template DNA, 15μL Taq enzyme premix, and 12μL sterile water. The reaction conditions were: pre-denaturation at 94℃ for 7min; denaturation at 94℃ for 1min; annealing at 55℃ for 1min; extension at 72℃ for 1.5min, 35 cycles, and storage at 4℃.

[0050] The PCR product was sequenced by Nanjing Qingke Biotechnology Co., Ltd., and the nucleotide sequence of strain SN-8-1 is shown in SEQ ID NO.1. The SEQ ID NO.1 sequence was compared with the BLAST similarity in GenBank to obtain related sequences with high similarity to the strain, and the phylogenetic tree of the strain was constructed using MEGA7.0 software ( Figure 3). Based on the above morphological observations and 16S sequence analysis results, the strain SN-8-1 was determined to be a member of Paenibacillus and was named SN-8-1. Its classification name was Paenibacillus sp.SN-8-1, which has been deposited in the China Center for Microbiological Culture Collection with the deposit number: CGMCCNO.1.60135, the deposit date: January 16, 2024, and the deposit address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing.

[0051] Example 2

[0052] 1. Phosphate solubilization ability of strain SN-8-1

[0053] The strain SN-8-1 was inoculated into an inorganic phosphorus solid culture medium to obtain an initial culture system; the culture medium was placed in a 30°C environment and shaken at 150 rpm for 5 days to obtain a termination culture system.

[0054] The method for determining the effective phosphorus concentration in the culture system is as follows:

[0055] Take 50mL of the terminated culture system, centrifuge at 6000rpm for 10min, and collect the supernatant; take nμL (usually 50-500μL) of the supernatant and add it to a 50mL volumetric flask, then add 2-3 drops of 2,6-dinitrophenol indicator, add 1mol / L sodium hydroxide aqueous solution until the system turns slightly yellow, add 5mL of molybdenum antimony anti-color developing agent, and then dilute to 50mL with water, which is the detection system, stand at 25℃ for 30min, and compare the color at 880nm to obtain the absorbance value a. Blank control: an equal volume of inorganic phosphorus liquid culture medium is used as the control solution, and the above steps are performed instead of the supernatant; the blank control is used for zeroing. Weigh 0.4394 g of potassium dihydrogen phosphate (super pure) dried at 105°C for 2 h, dissolve it in water, add 5 mL of concentrated sulfuric acid, and add water to make up to 1 L to obtain the phosphorus standard stock solution; use the phosphorus standard stock solution and water to prepare phosphorus standard solutions with different phosphorus concentrations; perform colorimetry on the phosphorus standard solution at 880 nm to prepare a standard curve of phosphorus element concentration (μg / mL) and absorbance value.

[0056] Effective phosphorus concentration in the culture system (mg / L) = ρ*V*D;

[0057] ρ is the phosphorus concentration (μg / mL) obtained from the standard curve using the absorbance value a; V is the volume of the detection system, which is 50 mL; D is the fractionation multiple, i.e. 1 / (n×10 -3 )mL.

[0058] The final soluble phosphorus content in the terminated culture system was measured to be 361.06 mg / L.

[0059] 2. Optimize the inorganic phosphorus liquid culture medium in the initial culture system (the following are all single-factor experimental methods) and screen the optimal phosphorus dissolution conditions as follows:

[0060] 1) Carbon source: 10 g / L (starch, maltose, glucose, sucrose, mannitol) to replace the carbon source in the phosphate-dissolving medium.

[0061] 2) Nitrogen source: 5g / L ((NH4)2SO4, NH4Cl, KNO3, NaNO3, peptone) to replace the nitrogen source in the phosphate-dissolving medium.

[0062] 3) Phosphorus source: 5g / L (AlPO4, FePO4, Ca3(PO)4) to replace the phosphorus source in the phosphate-dissolving medium.

[0063] 4) Original pH: single factor experimental method; the original pH value (4, 5, 6, 7, 8, 9) replaced the pH in the phosphate solubilization medium.

[0064] 5) Temperature: Temperature (20, 25, 30, 35, 40℃).

[0065] The cultured bacteria were made into bacterial liquids, inoculated into the inorganic phosphorus liquid culture medium under different conditions and cultured for 5 days to obtain the initial culture system; the culture was placed in different temperature environments and cultured at 150 rpm for 5 days to obtain the termination culture system. The soluble phosphorus content in the termination culture system was determined to screen out the optimal phosphorus dissolving conditions.

[0066] The results are as follows Figure 4 As shown in A, the effects of different carbon sources on the solubility of strain SN-8-1 are as follows: glucose>starch>maltose>sucrose>mannitol. When glucose was used as the carbon source, the soluble phosphorus content in the culture medium inoculated with strain SN-8-1 was the highest (361.06 mg / L), followed by starch and maltose. When mannitol was used as the carbon source, it did not have the ability to solubilize phosphorus. In short, glucose is the best carbon source for the phosphorus-solubilizing bacteria SN-8-1 to release effective P. In addition, the pH measurement results showed that, except for sucrose, the lower the final pH value, the higher the P release capacity in the liquid culture medium under different carbon source culture conditions.

[0067] The results are as follows Figure 4 As shown in B, the effects of different nitrogen sources on the solubility of strain SN-8-1 are as follows: ammonium chloride > ammonium sulfate > peptone > potassium nitrate > sodium nitrate. The most suitable nitrogen source is ammonium chloride. After 5 days of cultivation, the soluble phosphorus content of the strain reached 365.86 mg / L. In addition, NH4 + -N as a nitrogen source has a significantly better phosphorus dissolution effect than NO3 --N, in this application, when NaNO3 was used as the sole nitrogen source, the soluble phosphorus concentration of SN-8-1 was the lowest (78.80 mg / L). Interestingly, the pH value in the culture supernatant was opposite to the soluble phosphorus concentration measured under different nitrogen source culture conditions, that is, when ammonium chloride was used as the nitrogen source, the pH value of the liquid culture medium was the lowest.

[0068] The results are as follows Figure 4 As shown in Figure C, the effects of different phosphorus sources on the solubility of strain SN-8-1 are as follows: calcium phosphate > aluminum phosphate > iron phosphate. The most suitable phosphorus source is calcium phosphate, and the soluble phosphorus content of the strain reaches 310.10 mg / L after 5 days of cultivation.

[0069] The results are as follows Figure 4 As shown in Figure D, the effect of environmental pH on the P solubility of strain SN-8-1 was further verified by adjusting the original pH of the liquid culture medium (4-9). The results showed that the soluble phosphorus concentration in the culture supernatant reached a peak value (608.25 mg / L) at a pH of 4. When the original pH was raised to 9, the soluble phosphorus content reached a minimum level of 341.36 mg / L, indicating that pH had a significant effect on the phosphorus solubility of strain SN-8-1. Strain SN-8-1 is more suitable for growth in an acidic environment to improve soil phosphorus utilization.

[0070] The results are as follows Figure 4 As shown in Figure E, by adjusting the shaking incubation temperature (20, 25, 30, 35, 40°C), the effect of ambient temperature on the phosphorus solubility of strain SN-8-1 was further verified. The results showed that the soluble phosphorus concentration in the culture supernatant reached a peak value (337.27 mg / L) at a temperature of 25°C. When the culture temperature was 20°C, the soluble phosphorus content reached the lowest level of 297.15 mg / L, indicating that the culture temperature had a significant effect on the phosphorus solubility of strain SN-8-1.

[0071] Example 3

[0072] 1. Determination of organic acids (HPLC)

[0073] The strain SN-8-1 was inoculated into an inorganic phosphorus liquid culture medium, cultured at 30°C and 150 rpm for 5 days, and the supernatant was collected by centrifugation; it was then filtered into a liquid phase vial using a 0.22 μm nylon filter for further determination of organic acids.

[0074] Dilute the supernatant organic acid into a gradient standard solution with ultrapure water and filter it into a liquid phase vial using a 0.22 μm nylon filter.

[0075] Then the organic acid standard solution and the test solution were placed in a high performance liquid chromatograph (Thermo Fisher, USA). The chromatographic separation conditions were: 0.02 mol / L phosphate buffer (KH2PO4: methanol = 98:1 mixture), and the pH of the mixed mobile phase was adjusted to 2.6 with 1 mol / L phosphoric acid. The mobile phase flow rate was 0.5 mL / min, and the total operation time was 20 min. Organic acids were separated at 25 ° C using a 5C18-PAQ column (4.6×250 mm, 5 μm; COSMOSIL, Japan), with a sample volume of 10 μL. The retention time of each signal was recorded at 210 nm. The organic acids secreted by the isolated bacteria in this application were quantified by comparing their respective peak areas with the standard acid concentrations.

[0076] The results are as follows Figure 5 As shown in the results, the dissolution of insoluble P by phosphate-dissolving microorganisms mainly depends on the secretion of acidic substances. During the whole process, seven organic acids were detected in the culture supernatant of strain SN-8-1, including oxalic acid, fumaric acid, malic acid, lactic acid, acetic acid, citric acid and succinic acid. Among these organic acids, malic acid was secreted the most and played a leading role in the P dissolution process.

[0077] 2. Phosphatase assay

[0078] The strain SN-8-1 was inoculated into an inorganic phosphorus liquid culture medium, cultured at 30°C and 150 rpm for 5 days, and the supernatant was obtained by centrifugation; and the phosphatase content in the supernatant was measured.

[0079] Take 1mL of supernatant, add 4mL of MUB with a pH value of 6.5, and then add 1mL of 0.025mol / L disodium p-nitrophenyl phosphate solution, and shake for a few seconds. Plug the bottle stopper, incubate at 37℃ for 1h, add 1mL of 0.5mol / L calcium chloride and 4mL of 0.5mol / L sodium hydroxide, and filter the suspension with folded filter paper after shaking. Colorimetrically analyze the clarified filtrate at 420nm. This is the method for determining the activity of acid phosphatase. The pH value of the MUB reagent used for alkaline phosphatase is 11.

[0080] The results are as follows Figure 6 As shown, the acid phosphatase produced by strain SN-8-1 first increased and then decreased with time, and reached a maximum of 10.46 μmol / (L·h) on the third day. The alkaline phosphatase produced by SN-8-1 continued to increase with time, reaching a maximum of 18.76 μmol / (L·h) on the fifth day. The acid phosphatase activity secreted by strain SN-8-1 was higher than that of alkaline phosphatase on days 1, 2, and 3, and the alkaline phosphatase activity was higher than that of acid phosphatase in the middle and late stages of culture.

[0081] In summary, the novel phosphate-dissolving bacteria Paenibacillusa sp. SN-8-1 described in the present invention can not only dissolve insoluble inorganic phosphorus, but also prepare microbial fertilizers for solving the problem of low phosphorus utilization efficiency in agricultural and forestry lands, and has good application and promotion value.

[0082] Example 4

[0083] Test seeds: Soybean variety is Zhonghuang 57.

[0084] Use a 1% sodium hypochlorite solution by volume to disinfect soybean seeds with full grains and uniform size for 5 minutes, and then wash them 5 times with sterile water. After that, use 75% alcohol by volume to disinfect them for 5 minutes, and then wash them 5 times with sterile water. The experiment used plastic pots, each pot was filled with 2 kg of soil, and 2 g of calcium phosphate was applied to each pot. Each treatment was repeated 6 times, for a total of 12 pots. Planting in the greenhouse, 5 soybean seeds were sown in each pot, and watering was carried out regularly to keep moisture. After the seedlings grew for 7 days, they were thinned out, leaving 1 seedling with uniform growth in each pot. Starting from the 8th day, the strain was cultured overnight at 30°C and 150r / min, and the supernatant was discarded after centrifugation at 4°C and 5000r / min for 15 minutes. The precipitate was washed twice with sterile water, resuspended with sterile water, and the OD of the resuspended bacterial solution was adjusted. 600 =1, 3 mL was taken to irrigate the seedlings in the corresponding pots, and the roots were irrigated every 6 days, and the harvest was carried out on the 30th day. Soil and plant samples were collected to measure the plant height, plant fresh weight, and available phosphorus content in the rhizosphere soil of soybean.

[0085] The results are as follows Figure 7 As shown, soybean plants inoculated with SN-8-1 grew more vigorously and had well-developed root systems.

[0086] The results are shown in Table 1. The height of soybean plants inoculated with SN-8-1 was 41.49±0.87cm, which was significantly higher than the height of control plants. After inoculation with strain SN-8-1, the fresh weight of the aboveground part of soybean plants increased by 13.16% compared with the control group. The application of SN-8-1 significantly increased the fresh weight of the aboveground part of the plants. The fresh weight of the underground part of soybeans inoculated with SN-8-1 was 0.48±0.01g, which was significantly higher than the fresh weight of the underground part of control soybeans. The above results show that the application of SN-8-1 can significantly promote the growth of soybean plants.

[0087] The results are as follows Figure 8 As shown, the available phosphorus content in the soil inoculated with SN-8-1 was 13.21 mg / kg, which was 44.21% higher than that in the control group. The above results show that the available phosphorus content in the soil increased significantly after inoculation with SN-8-1.

[0088] Table 1 Phenotypic comparison of soybean plants after inoculation with SN-8-1

[0089] deal with Calcium phosphate application (g / basin) Plant height Fresh weight of above-ground part (g) Fresh weight of underground part (g) CK 2 38.78±0.42 1.90±0.10 0.44±0.02 SN-8-1 2 41.49±0.87 2.15±0.03 0.48±0.01

[0090] In summary, the novel phosphate-dissolving bacteria Paenibacillusa sp. SN-8-1 described in the present invention can not only dissolve insoluble inorganic phosphorus, but also prepare microbial fertilizers for solving the problem of low phosphorus utilization efficiency in agricultural and forestry lands, and has good application and promotion value.

[0091] The above description is only illustrative rather than restrictive of the present invention. Those skilled in the art will understand that many modifications, changes or equivalents may be made without departing from the spirit and scope defined by the appended claims, but all will fall within the scope of protection of the present invention.

Claims

1. A strain of Paenibacillus SN-8-1, which is classified and named Paenibacillus sp.SN-8-1 has been deposited in the China Microbiological Culture Collection, with the deposit number: CGMCC NO.1.60135, the deposit date: January 16, 2024, and the deposit address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing.

2. Use of the Paenibacillus SN-8-1 according to claim 1 in promoting soybean growth.

3. The use of Paenibacillus SN-8-1 in promoting soybean growth according to claim 2, characterized in that: The method of promoting soybean growth includes promoting the increase of soybean plant height, promoting the increase of fresh weight of the above-ground part of soybean, and promoting the increase of fresh weight of the underground part of soybean.

4. Use of the Paenibacillus SN-8-1 according to claim 1 in secreting organic acids, wherein the organic acids are oxalic acid, fumaric acid, malic acid, lactic acid, acetic acid, citric acid and succinic acid.

5. Use of the Paenibacillus SN-8-1 according to claim 1 in secreting phosphatase, wherein the phosphatase is alkaline phosphatase and acid phosphatase.

6. Use of the Paenibacillus SN-8-1 according to claim 1 in dissolving poorly soluble inorganic phosphorus.

7. Use of the Paenibacillus SN-8-1 according to claim 1 in improving soil fertility.

8. The use of Paenibacillus SN-8-1 in improving soil fertility according to claim 7, characterized in that: The improving soil fertility is to promote the increase of the effective phosphorus content in the soil.

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