Lysinibacillus fusiformis LPV2.3 strain and application thereof in phosphate solubilization

Abstract

The invention discloses a lysinibacillus fusiformis LPV2.3 strain and an application of the lysinibacillus fusiformis LPV2.3 strain in phosphate solubilization. The lysinibacillus fusiformis LPV2.3 strain disclosed by the invention is preserved in the Guangdong Microbial Culture Collection Center on October 23, 2024, and the preservation number of the lysinibacillus fusiformis LPV2.3 strain is GDMCC (China General Microbiological Culture Collection Center): 65323. The LPV2.3 strain can be used for effectively dissolving calcium phosphorus, aluminum phosphorus and / or iron phosphorus in soil, namely the LPV2.3 strain can be used for activating insoluble phosphorus in the soil and increasing the content of available phosphorus in the soil, so that the phosphorus nutrition of the plant rhizosphere soil is improved. In addition, the LPV2.3 strain can secrete IAA, siderophores and the like, and plant growth is promoted. The LPV2.3 strain can improve the utilization rate of phosphorus in soil and reduce the use of chemical fertilizers such as phosphate fertilizer and the like.

Description

Technical Field

[0001] The present invention belongs to the field of microbial technology, and more specifically, relates to a lysinibacillus fusiformis LPV2.3 strain and its application in phosphate solubilization. Background Art

[0002] Phosphorus is one of the essential nutrients for plants. Physiological metabolic processes such as ATP synthesis, nucleic acid synthesis, and signal transduction in plants all require the participation of phosphorus. However, most of the phosphorus in the soil is fixed in the form of calcium phosphorus (Ca-P), aluminum phosphorus (Al-P), and iron phosphorus (Fe-P). This type of phosphorus cannot be used by plants, resulting in a lack of available phosphorus in the soil, which limits the growth of plants, resulting in short plants, and reduced yield and quality. At present, production mainly improves plant phosphorus deficiency by breeding varieties with high phosphorus utilization efficiency and increasing the application of phosphorus fertilizers. However, the breeding cycle is long and it is impossible to improve the phosphorus deficiency of plants in time. Blindly increasing the application of phosphorus fertilizers can easily cause environmental pollution, which is not in line with the needs of green agriculture and sustainable agricultural development.

[0003] Using phosphate-dissolving bacteria to improve plant phosphorus nutrition and promote efficient absorption and utilization of nutrients is a current hot topic. Phosphate-dissolving bacteria can alleviate the negative effects of phosphorus deficiency on plants and promote plant growth through direct or indirect effects. However, when using phosphate-dissolving bacteria to dissolve insoluble phosphorus in the soil, calcium phosphorus activation is the main method. In acidic soils, the content of iron phosphorus is higher, followed by aluminum phosphorus and calcium phosphorus. Focusing only on the activation of calcium phosphorus cannot effectively improve plant phosphorus nutrition and increase the utilization rate of phosphorus in acidic soils. Therefore, it is necessary to explore strains that can effectively activate insoluble phosphorus such as iron phosphorus and aluminum phosphorus. Although there are reports of phosphate-dissolving bacteria that can dissolve calcium phosphorus, different strains not only have great differences in phosphorus dissolving ability, but also have different solubility abilities for different insoluble phosphorus, which makes it difficult to discover strains that can effectively activate insoluble phosphorus such as iron phosphorus and aluminum phosphorus. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a Lysinibacillus fusiformis LPV2.3 strain, which can effectively dissolve calcium phosphorus, aluminum phosphorus and / or iron phosphorus, and improve the phosphorus nutrition of plant rhizosphere soil.

[0005] The first object of the present invention is to provide a lysinibacillus fusiformis LPV2.3 strain.

[0006] The second object of the present invention is to provide a bacterial agent containing the LPV2.3 strain or containing the LPV2.3 strain and its fermentation culture liquid.

[0007] The third object of the present invention is to provide the use of the LPV2.3 strain or the bacterial agent in dissolving insoluble phosphorus.

[0008] The fourth object of the present invention is to provide the use of the LPV2.3 strain or the bacterial agent in the preparation of a product for dissolving poorly soluble phosphorus.

[0009] The fifth object of the present invention is to provide the use of the LPV2.3 strain or the bacterial agent in promoting plant growth.

[0010] The sixth object of the present invention is to provide the use of the LPV2.3 strain or the bacterial agent in the preparation of a preparation for promoting plant growth.

[0011] The seventh object of the present invention is to provide the use of the LPV2.3 strain or the bacterial agent in increasing the phosphorus content of plants.

[0012] The eighth objective of the present invention is to provide the use of the LPV2.3 strain or the bacterial agent in the preparation of a product for increasing the phosphorus content of plants.

[0013] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0014] The present invention obtains a spindle-shaped Lysinibacillus fusiformis strain through separation and purification, and is named as LPV2.3 strain. According to the test, the LPV2.3 strain of the present invention can effectively dissolve insoluble phosphorus such as calcium phosphorus, aluminum phosphorus, and iron phosphorus, and promote the growth of plants such as Arabidopsis, soybean, and corn. Therefore, the present invention requests protection for the LPV2.3 strain and its related applications.

[0015] The present invention claims protection for a Lysinibacillus fusiformis LPV2.3 strain, which is deposited in Guangdong Microbial Culture Collection Center (GDMCC) on October 23, 2024, and the deposit number is GDMCC No: 65323.

[0016] The present invention also seeks to protect a bacterial agent, wherein the bacterial agent contains the LPV2.3 strain.

[0017] Optionally, the bacterial agent also contains fermentation culture broth of the LPV2.3 strain.

[0018] Optionally, the fermentation culture broth is obtained by inoculating LPV2.3 strain into LB medium for fermentation culture.

[0019] Optionally, the culture temperature is 28-32°C and the culture rotation speed is 150-200 rpm.

[0020] Since the LPV2.3 strain of the present invention can effectively dissolve insoluble phosphorus such as calcium phosphorus, aluminum phosphorus, iron phosphorus, etc., the present invention seeks to protect the use of the LPV2.3 strain or the bacterial agent in dissolving insoluble phosphorus.

[0021] The present invention also seeks to protect the use of the LPV2.3 strain or the bacterial agent in the preparation of a product for dissolving insoluble phosphorus.

[0022] Specifically, the sparingly soluble phosphorus is sparingly soluble phosphate.

[0023] Specifically, the poorly soluble phosphate is calcium phosphate, aluminum phosphate and / or iron phosphate.

[0024] Since the LPV2.3 strain of the present invention can significantly promote the growth of plants such as Arabidopsis, soybean, and corn, the present invention also seeks to protect the use of the LPV2.3 strain or the bacterial agent in promoting plant growth.

[0025] The present invention also claims to protect the use of the LPV2.3 strain or the bacterial agent in the preparation of a preparation for promoting plant growth.

[0026] Optionally, the plant is Arabidopsis thaliana, soybean and / or corn.

[0027] Specifically, the promoting plant growth includes promoting the growth of plant lateral roots and increasing the fresh weight and / or dry weight of plants.

[0028] The present invention also claims to protect the use of the LPV2.3 strain or the bacterial agent in increasing the phosphorus content of plants.

[0029] The present invention also claims to protect the use of the LPV2.3 strain or the bacterial agent in the preparation of a product for increasing the phosphorus content of plants.

[0030] In particular, the application is to increase the phosphorus content of plants grown under low phosphorus conditions.

[0031] Specifically, the low-phosphorus condition refers to an effective phosphorus concentration in the plant growth environment that is lower than that required for normal plant growth.

[0032] Optionally, the plant is soybean and / or corn.

[0033] The present invention has the following beneficial effects:

[0034] The present invention provides a spindle-shaped lysinibacillus LPV2.3 strain, which is deposited in the Guangdong Provincial Microbial Culture Collection Center on October 23, 2024, and the deposit number is GDMCCNo: 65323. The LPV2.3 strain described in the present invention can effectively dissolve calcium phosphorus, aluminum phosphorus and / or iron phosphorus in the soil, that is, the LPV2.3 strain can activate the insoluble phosphorus in the soil, increase the effective phosphorus content in the soil, and thus improve the phosphorus nutrition of the rhizosphere soil of plants. In addition, the LPV2.3 strain described in the present invention can also secrete IAA and siderophores, etc., to promote plant growth. The LPV2.3 strain described in the present invention can improve the utilization rate of phosphorus in the soil and reduce the use of chemical fertilizers such as phosphate fertilizers. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is the colony morphology of the LPV2.3 strain.

[0036] Figure 2 This is a phylogenetic tree constructed based on the 16S rDNA of LPV2.3 strain.

[0037] Figure 3 This is the change of culture medium after LPV2.3 strain was cultured in King liquid medium, SSM liquid medium, Montkina Ca-P liquid medium, Montkina Al-P liquid medium and Montkina Fe-P liquid medium.

[0038] Figure 4 The results show the effect of LPV2.3 strain on the growth of Arabidopsis thaliana cultured in insoluble Ca-P medium; a in the figure is a comparison of Arabidopsis thaliana plants in the inoculated group and the control group; b in the figure is the statistical result of the number of lateral roots of Arabidopsis thaliana plants in the inoculated group and the control group; c in the figure is the fresh weight of Arabidopsis thaliana plants in the inoculated group and the control group; *p<0.05; ***p<0.001.

[0039] Figure 5 The results show the effect of LPV2.3 strain on the growth of Arabidopsis thaliana cultured in insoluble Fe-P medium; a in the figure shows the statistical result of the number of lateral roots of Arabidopsis thaliana plants in the inoculated group and the control group; b in the figure shows the fresh weight of Arabidopsis thaliana plants in the inoculated group and the control group; *p<0.05; **p<0.01 in the figure.

[0040] Figure 6 The results show the effect of LPV2.3 strain on the growth of soybeans grown in low-phosphorus soil; a in the figure is a comparison of soybean plants in the inoculated group and the control group; b to e in the figure are the dry weight, mature leaf chlorophyll concentration, plant phosphorus concentration and plant phosphorus content measurement results of soybean plants in the inoculated group and the control group, respectively; *p<0.05; **p<0.01; ***p<0.001.

[0041] Figure 7 The results show the effect of LPV2.3 strain on the growth of corn grown in low-phosphorus soil; a in the figure is a comparison of corn plants in the inoculated group and the control group; b to e in the figure are the measurement results of dry weight, mature leaf chlorophyll concentration, plant phosphorus content and total root length of corn plants in the inoculated group and the control group, respectively; **p<0.01; ***p<0.001. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with the accompanying drawings and specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0043] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0044] The LPV2.3 strain described in the embodiment of the present invention is Lysinibacillus fusiformis, which was deposited in the Guangdong Provincial Microbiological Culture Collection Center on October 23, 2024, with a collection number of GDMCC No: 65323, and the collection address is 5th Floor, Laboratory Building, No. 100 Xianlie Middle Road, Yuexiu District, Guangzhou City, Guangdong Province.

[0045] The preparation methods of the culture medium and solution used in the embodiments of the present invention are as follows:

[0046] LB medium: 10 g of tryptone, 5 g of yeast extract, 10 g of sodium chloride, 15 g of agar, distilled water to 1 L, adjust the pH to 7.0; sterilize at 121°C for 15 min.

[0047] King liquid medium: 20 g peptone, 1.725 g potassium hydrogen phosphate, 15 mL glycerol, 1.5 g magnesium sulfate heptahydrate, 0.1 g tryptophan, distilled water to 1 L, adjust pH to 7.2; sterilize at 121°C for 15 min.

[0048] SSM liquid culture medium: 4.0 g succinic acid, 1 g ammonium sulfate, 0.2 g magnesium sulfate, 4.75 g potassium hydroxide, distilled water to 1 L, adjust pH to 7.0; sterilize at 121°C for 15 min.

[0049] Montgina inorganic phosphorus medium Ca-P: glucose 10g, ammonium sulfate 0.5g, sodium chloride 0.3g, potassium chloride 0.3g, magnesium sulfate 0.3g, ferrous sulfate 0.03g, manganese sulfate 0.03g, calcium phosphate 5.0g, distilled water to 1L, adjust pH to 7.0; sterilize at 121℃ for 15min.

[0050] Montgina inorganic phosphorus medium Fe-P: glucose 10g, ammonium sulfate 0.5g, sodium chloride 0.3g, potassium chloride 0.3g, magnesium sulfate 0.3g, manganese sulfate 0.03g, iron phosphate 4.86g, distilled water to 1L, adjust pH to 7.0; sterilize at 121℃ for 15min.

[0051] Montgina inorganic phosphorus medium Al-P: glucose 10g, ammonium sulfate 0.5g, sodium chloride 0.3g, potassium chloride 0.3g, magnesium sulfate 0.3g, ferrous sulfate 0.03g, manganese sulfate 0.03g, aluminum phosphate 3.93g, distilled water to 1L, adjust pH to 7.0; sterilize at 121℃ for 15min.

[0052] MS medium: 1900 mg potassium nitrate, 1650 mg ammonium nitrate, 170 mg potassium dihydrogen phosphate, 370 mg magnesium sulfate, 440 mg calcium chloride, 0.83 mg potassium iodide, 6.2 mg boric acid, 22.3 mg manganese sulfate, 8.6 mg zinc sulfate, 0.25 mg sodium molybdate, 0.025 mg copper sulfate, 0.025 mg cobalt chloride, 37.25 mg disodium ethylenediaminetetraacetic acid, 27.85 mg ferrous sulfate, 100 mg inositol, 2 mg glycine, 0.1 mg thiamine hydrochloride, 0.5 mg pyridoxine hydrochloride, 0.5 mg niacin, 30 g sucrose, 5 g agar, distilled water to 1 L, adjust pH to 5.8; sterilize at 121°C for 15 min.

[0053] Salkowski colorimetric reagent: Add 1 mL of 0.5 mol / L FeCl3 to 50 mL of 35% perchloric acid.

[0054] Molybdenum antimony sulfate stock solution: Measure 126mL of concentrated sulfuric acid, slowly add it into 100mL of water, stir constantly, and cool; weigh another 10g of ground ammonium molybdate and dissolve it in 300mL of water at 60℃, slowly pour the sulfuric acid solution into the ammonium molybdate solution after cooling, then add 100mL of 0.5% potassium antimony stone solution, dilute with water to 1000mL after cooling, shake well and store in a brown reagent bottle.

[0055] Molybdenum antimony anticolorimetric agent: Weigh 1.5 g ascorbic acid and dissolve it in 100 mL molybdenum antimony stock solution.

[0056] CAS blue detection solution: prepare solution A and solution B separately, slowly add solution A into solution B along the wall of the beaker, and gently shake to mix solution A and solution B evenly to obtain CAS blue detection solution;

[0057] Solution A: Dissolve 0.079 chrome azurol S (CAS) in 50 mL of deionized water, then add 10 mL of 1 mmol / L FeCl3 solution (containing 10 mmol / L HCI);

[0058] Solution B: Dissolve 0.069 of hexadecyltrimethylammonium bromide (HDTMA) in 40 mL of deionized water.

[0059] Example 1 Acquisition and identification of LPV2.3 strain

[0060] 1. Isolation and purification of LPV2.3 strain

[0061] The LPV2.3 strain of the present invention is isolated from soybean rhizosphere soil. The collected soil sample is resuspended with sterile water and inoculated into a Montkina Ca-P solid culture medium, and the colonies grown on the culture medium are screened to screen strains with relatively stronger phosphate solubilization ability, and the screened strains with relatively stronger phosphate solubilization ability are purified, and the purified strain is the LPV2.3 strain.

[0062] 2. Observation of colony morphology of LPV2.3 strain

[0063] Take the purified LPV2.3 strain, streak it into LB medium, and observe its single colony. The colony morphology of LPV2.3 strain is as follows Figure 1 As shown. Figure 1 It can be seen that the colonies of the LPV2.3 strain are round, with a convex center, milky white to yellowish in color, and the bacteria appear moist.

[0064] 3. Sequencing and identification of LPV2.3 strains

[0065] The genomic DNA of the purified LPV2.3 strain was extracted, and the 16S rDNA of the LPV2.3 strain was amplified using universal primers of 16S rDNA and sequenced and compared by BLAST.

[0066] The sequencing results show that the 16S rDNA sequence of the LPV2.3 strain is as follows (SEQ ID NO.1):

[0067]

[0068] The phylogenetic tree was constructed based on the 16S rDNA of the LPV2.3 strain, such as Figure 2 As shown. Figure 2 It can be seen that the similarity between LPV2.3 strain and multiple different strains of Lysinibacillus fusiformis is above 98%. Combining the strain morphology, culture characteristics and physiological and biochemical analysis results, LPV2.3 strain was identified as Lysinibacillus fusiformis.

[0069] The LPV2.3 strain was preserved and was deposited in the Guangdong Provincial Microbiological Culture Collection Center on October 23, 2024. The preservation number is GDMCC No: 65323. The preservation address is 5th Floor, Compound Experimental Building, No. 100 Xianlie Middle Road, Yuexiu District, Guangzhou City, Guangdong Province.

[0070] Example 2 Analysis of the Growth-Promoting Effect of LPV2.3 Strain

[0071] 1. Detection of indoleacetic acid (IAA) production capacity

[0072] Take a conical flask containing 30 mL of sterile King liquid culture medium, inoculate the LPV2.3 strain into the culture medium at a 1% (v / v) inoculation rate, and culture with shaking at 30°C and 180 r / min. After culturing for 3 days, take out the conical flask, centrifuge it and the uninoculated King liquid culture medium at 10,000 rpm for 10 min, take the supernatant and an equal volume of Salkowski colorimetric agent, mix them, and let them stand at room temperature in the dark for 30 min, then measure the absorbance at a wavelength of 530 nm.

[0073] The IAA production capacity of the strain was evaluated by calculating the IAA concentration; the standard curve formula for calculating the IAA concentration was Y=0.0167X; wherein Y was the difference between the OD530 after inoculation and the OD530 without inoculation, and X was the measured IAA concentration.

[0074] The results of the IAA production ability test of LPV2.3 strain are shown in Table 1.

[0075] 2. Siderophore production capacity test

[0076] Take three conical flasks containing 30 mL of sterile SSM liquid culture medium and number them 1, 2, and 3 respectively; inoculate the LPV2.3 strain at a 1% (v / v) inoculation amount into the numbered SSM culture medium, and culture with shaking at 30°C and 180 r / min. After culturing for 3 days, take out the conical flask, centrifuge it and the uninoculated SSM liquid culture medium at 10000 rpm for 10 min, take the supernatant and an equal volume of CAS blue detection solution, mix them, and let them stand at room temperature in the dark for 30 min, then measure the absorbance at a wavelength of 630 nm.

[0077] The siderophore production capacity of the strain was evaluated by calculating the siderophore production; the standard curve formula for calculating the siderophore production was Y=32.99X+0.2746; wherein X was the measured siderophore ratio.

[0078] Iron carrier ratio = [(OD value after inoculation - OD value before inoculation) / OD value before inoculation] × 100%

[0079] The results of the test on the ability of LPV2.3 strain to produce siderophore are shown in Table 1.

[0080] 3. Ca-P desorption capacity test

[0081] Take a conical flask containing 30 mL of sterile Montana inorganic phosphorus liquid culture medium Ca-P, inoculate the LPV2.3 strain into the culture medium at a rate of 1% (v / v), and culture with shaking at 30°C and 180 r / min. After culturing for 3 days, take out the conical flask, centrifuge it and uninoculated Montana inorganic phosphorus liquid culture medium Ca-P at 10,000 rpm for 10 min, take the supernatant and the prepared molybdenum antimony anticolorimetric agent at a volume ratio of 1:200, mix them evenly, and let them stand at room temperature in the dark for 30 min, then measure the absorbance at a wavelength of 700 nm.

[0082] The Ca-P decomposition ability of the strain was evaluated by calculating the effective phosphorus concentration in the Ca-P medium; the standard curve formula for calculating the effective phosphorus concentration in the Ca-P medium was Y=1.089X+0.0152; wherein X was the difference between the OD700 after inoculation and the OD700 before inoculation, and Y was multiplied by 200 to obtain the effective phosphorus concentration in the Ca-P medium.

[0083] The results of the Ca-P degrading ability test of the LPV2.3 strain are shown in Table 1.

[0084] 4. Al-P solution ability test

[0085] Take a conical flask containing 30 mL of sterile Montana inorganic phosphorus liquid culture medium Al-P, inoculate the LPV2.3 strain into the culture medium at a 1% (v / v) inoculation rate, and culture under shaking conditions at 30°C and 180 r / min. After culturing for 3 days, take out the conical flask, centrifuge it and uninoculated Montana inorganic phosphorus liquid culture medium Ca-P at 10000 rpm for 10 min, take the supernatant and the prepared molybdenum antimony anticolorimetric agent at a volume ratio of 1:40, mix them evenly, and let them stand at room temperature in the dark for 30 min, then measure the absorbance at a wavelength of 700 nm.

[0086] The Al-P degrading ability of the strain was evaluated by calculating the available phosphorus concentration in the Al-P medium; the standard curve formula for calculating the available phosphorus concentration in the Al-P medium was Y=1.089X+0.0152; wherein X was the difference between the OD700 after inoculation and the OD700 before inoculation, and Y was multiplied by 40 to obtain the available phosphorus concentration in the Al-P medium.

[0087] The results of the Al-P degrading ability test of LPV2.3 strain are shown in Table 1.

[0088] 5. Fe-P decomposition ability test

[0089] Take a conical flask containing 30 mL of sterile Montana inorganic phosphorus liquid culture medium Fe-P, inoculate the LPV2.3 strain into the culture medium at a rate of 1% (v / v), and culture with shaking at 30°C and 180 r / min. After culturing for 3 days, take out the conical flask, centrifuge it and uninoculated Montana inorganic phosphorus liquid culture medium Fe-P at 10,000 rpm for 10 min, take the supernatant and the prepared molybdenum antimony anticolorimetric agent at a volume ratio of 1:200, mix them evenly, and let them stand at room temperature in the dark for 30 min, then measure the absorbance at a wavelength of 700 nm.

[0090] The Fe-P degrading ability of the strain was evaluated by calculating the effective phosphorus concentration in the Fe-P medium; the standard curve formula for calculating the effective phosphorus concentration in the Fe-P medium was Y=1.089X+0.0152; wherein X was the difference between the OD700 after inoculation and the OD700 before inoculation, and Y was multiplied by 200 to obtain the effective phosphorus concentration in the Fe-P medium.

[0091] The results of the Fe-P degrading ability test of LPV2.3 strain are shown in Table 1.

[0092] Table 1 Analysis results of the growth-promoting effect of LPV2.3 strain

[0093]

[0094] Combined with the changes in the culture medium after LPV2.3 strain was cultured in King liquid medium, SSM liquid medium, Montkina Ca-P liquid medium, Montkina Al-P liquid medium and Montkina Fe-P liquid medium (such as Figure 3 From the results shown in the table 1, it can be seen that the LPV2.3 strain can change the King liquid culture medium from yellow transparent to milky yellow turbid, and the Salkowski colorimetric agent from light yellow to pink, and has a strong ability to produce IAA; the LPV2.3 strain can make the SSM culture medium turbid, and the CAS detection liquid change from blue to red, and has a strong ability to produce siderophores; the LPV2.3 strain can dissolve the precipitates in the Montkina Ca-P liquid culture medium, the Montkina Al-P liquid culture medium, and the Montkina Fe-P liquid culture medium, indicating that the LPV2.3 strain has a very strong ability to dissolve different insoluble phosphorus, and has a strong advantage in phosphorus activation in low-phosphorus soils.

[0095] Example 3 Effect of LPV2.3 strain on the growth of Arabidopsis thaliana cultured in a medium containing poorly soluble phosphorus

[0096] 1. Planting of Arabidopsis

[0097] Arabidopsis seeds were soaked in sterile water for 30 min, then soaked in 75% alcohol for 30 s and rinsed with sterile water 2-3 times, then soaked in NaClO for 10 min for disinfection, and rinsed with sterile water 3-5 times; the disinfected Arabidopsis seeds were planted in MS culture medium, sealed and placed at 4 ° C for vernalization for 2 days, and then placed in an Arabidopsis culture box; after the Arabidopsis seeds germinated, Arabidopsis seedlings with consistent growth were selected and transplanted into Montana Ca-P solid culture medium and Montana Fe-P solid culture medium respectively; the amount of culture medium in each plate was 30 mL, 3 seedlings were planted on each plate as one replicate, and each treatment had three replicates.

[0098] 2. Inoculation of LPV2.3 strain

[0099] The LPV2.3 strain was cultured in LB liquid medium and the concentration was adjusted to 1×10 9 cfu / mL, centrifuge at 5000rpm for 10min in a high-speed centrifuge, pour off the supernatant, add an equal amount of sterilized distilled water to prepare a bacterial suspension for later use; add 20μL of the prepared bacterial suspension to the culture medium with Arabidopsis seedlings transplanted at a distance of 10cm from the seedlings, add an equal amount of distilled water to the control group, and continue to culture in an Arabidopsis incubator.

[0100] 3. Arabidopsis growth survey

[0101] The Arabidopsis plants were harvested 20 days after inoculation and transplantation, and the number of lateral roots and fresh weight of each plant were observed and measured.

[0102] The results of the effect of LPV2.3 strain on the growth of Arabidopsis thaliana cultured in insoluble Ca-P medium are shown in Figure 4 As shown. Figure 4 It can be seen that in the insoluble Ca-P medium, the growth of Arabidopsis thaliana inoculated with LPV2.3 strain group was significantly better (see Figure 4 At the same time, the statistical results of the number of lateral roots ( Figure 4 b) and fresh weight results ( Figure 4 As shown in c), the number of lateral roots and fresh weight of Arabidopsis thaliana treated with bacteria increased significantly (p<0.05), reaching 2.96 times and 1.34 times that of the control group, respectively.

[0103] The results of the effect of LPV2.3 strain on the growth of Arabidopsis thaliana cultured in insoluble Fe-P medium are shown in Figure 5 As shown. Figure 5 It can be seen that in the insoluble Fe-P culture medium, the number of lateral roots and fresh weight of Arabidopsis thaliana treated with bacteria increased by 27% and 21%, respectively, which was significantly higher than that of the control group (p<0.05).

[0104] The above results show that the LPV2.3 strain can dissolve insoluble calcium phosphate and iron phosphate, promote the development of plant roots, and promote the growth of the aboveground parts of the plant while promoting the growth of lateral roots.

[0105] Example 4 Effect of LPV2.3 strain on the growth of soybeans grown in low-phosphorus soil

[0106] This example tests the effect of LPV2.3 strain on the growth of soybeans grown in low-phosphorus soil through a pot experiment. The experiment was set up in a greenhouse and the soybean variety used was "Yuechun 03-3".

[0107] Soybean seeds were directly sown in potted plants. Starting from the first week of sowing, a bacterial suspension was added to the roots at a rate of 50 mL / plant every week (the preparation method of the bacterial suspension was the same as in Example 3). An equal amount of sterilized aqueous solution was added to the control group. Four pots were treated in each of the two groups, and two biological replicates were performed in each pot. Samples were collected two months after soybean sowing (pod-setting stage). After sampling, some fresh mature leaves were taken to determine the chlorophyll concentration. The remaining plants were dried at 60°C to constant weight and the dry weight was determined. The phosphorus concentration of the dried plant samples was determined by the molybdenum antimony colorimetric method and the phosphorus content of the whole soybean was calculated.

[0108] The results of the effect of LPV2.3 strain on the growth of soybeans grown in low-phosphorus soil are as follows Figure 6 As shown; Figure 6 a in the figure is a comparison of soybean plants in the inoculated group and the control group; Figure 6 b~e in the figure are the results of soybean plant dry weight, mature leaf chlorophyll concentration, plant phosphorus concentration and plant phosphorus content. Figure 6 The results show that inoculation with LPV2.3 strain can significantly promote the growth of soybeans grown in low-phosphorus soil and significantly increase the dry weight of soybean plants (p<0.05), with an increase of 16.4% ( Figure 6 b); at the same time, the chlorophyll concentration of mature leaves increased by 33.7% under the influence of LPV2.3 strain ( Figure 6 c); after inoculation with LPV2.3 strain, the phosphorus concentration and phosphorus content of soybean plants reached 1.17 and 1.36 times that of the control group, respectively ( Figure 6 The above results show that the LPV2.3 strain can dissolve the insoluble phosphorus in low-phosphorus soil, improve the absorption of phosphorus nutrients by soybeans, and promote plant growth and development.

[0109] Example 5 Effect of LPV2.3 strain on the growth of corn grown in low-phosphorus soil

[0110] This example tests the effect of LPV2.3 strain on the growth of corn grown in low-phosphorus soil through a pot experiment. The experiment was set up in a greenhouse and the corn variety used was "Huazhen" sweet corn.

[0111] Corn seeds were directly sown in potted plants. From the first week of sowing, 50 mL / plant of bacterial suspension was added to the roots every week (the preparation method of bacterial suspension was the same as in Example 3). An equal amount of sterilized aqueous solution was added to the control group. Four pots were treated in each of the two groups, and two biological replicates were performed in each pot. Samples were collected two months after corn sowing (large trumpet stage). After sampling, some fresh mature leaves were taken to determine the chlorophyll concentration. At the same time, the root system was scanned to analyze the total root length. The remaining plants were dried at 60°C to constant weight and the dry weight was determined. The phosphorus concentration of the dried plant samples was determined by molybdenum antimony colorimetry and the phosphorus content of the whole corn was calculated.

[0112] The results of the effect of LPV2.3 strain on the growth of corn grown in low-phosphorus soil are as follows Figure 7 As shown; Figure 7 a in the figure is a comparison of corn plants in the inoculated group and the control group; Figure 7 b~e in the figure are the results of the measurement of corn plant dry weight, mature leaf chlorophyll concentration, plant phosphorus content and total root length. Figure 7 It can be seen that inoculation with LPV2.3 strain can significantly promote the growth of corn grown in low-phosphorus soil and significantly increase the dry weight of the whole corn plant (p<0.001), with an increase of 50.4% ( Figure 7 b); at the same time, the chlorophyll concentration of mature leaves increased by 57.7% under the influence of LPV2.3 strain ( Figure 7 c); after inoculation with LPV2.3 strain, the phosphorus content of corn plants reached 1.49 times that of the control group ( Figure 7d); The total root length of corn under the influence of LPV2.3 strain increased by 34.6% compared with the control group ( Figure 7 The above results show that the LPV2.3 strain can dissolve the insoluble phosphorus in low-phosphorus soil, improve the absorption of phosphorus nutrients by corn, and promote plant growth and development.

[0113] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A strain of Lysinibacillus fusiformis LPV2.3, characterized in that: The strain is deposited in Guangdong Provincial Microbiological Culture Collection Center, the preservation date is October 23, 2024, and the preservation number is GDMCC No: 65323.

2. A bacterial agent, characterized in that Contains the LPV2.3 strain according to claim 1.

3. The bacterial agent according to claim 2, characterized in that: It also contains the fermentation culture broth of the LPV2.3 strain according to claim 1.

4. Use of the LPV2.3 strain according to claim 1 or the bacterial agent according to any one of claims 2 to 3 in dissolving sparingly soluble phosphorus, characterized in that: The sparingly soluble phosphorus is sparingly soluble phosphate, and the sparingly soluble phosphate includes aluminum phosphate and / or iron phosphate.

5. Use of the LPV2.3 strain according to claim 1 or the bacterial agent according to any one of claims 2 to 3 in the preparation of a product for dissolving poorly soluble phosphorus, characterized in that: The sparingly soluble phosphorus is sparingly soluble phosphate, and the sparingly soluble phosphate includes aluminum phosphate and / or iron phosphate.

6. The use according to claim 4 or 5, characterized in that: The poorly soluble phosphates also include calcium phosphate.

7. Use of the LPV2.3 strain according to claim 1 or the bacterial agent according to any one of claims 2 to 3 in promoting plant growth, characterized in that: The plant is Arabidopsis thaliana, soybean and / or corn.

8. Use of the LPV2.3 strain according to claim 1 or the bacterial agent according to any one of claims 2 to 3 in the preparation of a preparation for promoting plant growth, characterized in that: The plant is Arabidopsis thaliana, soybean and / or corn.

9. Use of the LPV2.3 strain according to claim 1 or the bacterial agent according to any one of claims 2 to 3 in increasing the phosphorus content of plants, characterized in that: The plants are soybean and / or corn.

10. Use of the LPV2.3 strain according to claim 1 or the bacterial agent according to any one of claims 2 to 3 in the preparation of a product for increasing the phosphorus content of plants, characterized in that: The plants are soybean and / or corn.

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