Lysinibacillus fusiformis as well as fungicide and application thereof

Abstract

The invention belongs to the technical field of agricultural microorganisms, and particularly relates to lysinibacillus fusiformis as well as a fungicide and application thereof. The invention discloses a Lysinibacillus fusiformis strain, which is preserved in the China General Microbiological Culture Collection Center (CGMCC), and the preservation number is CGMCC No.33305. The nucleotide sequence of 16S rRNA of the Lysinibacillus fusiformis strain is shown as SEQ ID NO: 1. The Lysinibacillus fusiformis strain can tolerate 100 mM of sodium selenite, has strong selenium salt reduction capability, can secrete IAA and produce siderophores, and has nitrogen fixation capability. The strain can be applied to selenium pollution treatment and nano-selenium preparation; the method can be applied to IAA production, siderophore production and nitrogen fixation.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural microorganisms and relates to a lysine bacillus fusiformis and a bacterial agent and application thereof. Background Art

[0002] Endophytes include bacteria and fungi that can infect plants asymptomatically or cause only mild symptoms in tissues such as roots, stems, and leaves. Because they live within plant tissues, do not cause substantial damage to the host plant, and are beneficial to the plant, endophytes are important biological resources, present in nearly all higher-order plants and supporting growth under normal and some exceptional conditions. Plant endophytes contribute significantly to the adaptation and survival of host plants under stressful conditions, enhancing the production and secretion of important secondary metabolites. Their potential applicability in agriculture, medicine, food, and horticulture makes them crucial for host growth and defense. Furthermore, endophytes are diverse, with different endophytes interacting differently with plants and their environments. Some endophytes also participate in the migration and transformation of certain elements in the environment, making plant endophytes a research hotspot in disciplines such as microbiology, botany, plant protection, agronomy, ecology, and traditional Chinese medicine resources.

[0003] Selenium is an essential trace element for the human body, serving numerous biological functions. Selenium deficiency can lead to numerous diseases. However, the human body cannot synthesize selenium on its own and must obtain it from the external environment. Currently, the most widely used method is to consume selenium-enriched plant products, such as selenium-enriched tea. Organic selenium accounts for 80% of the total selenium content in selenium-enriched tea, facilitating its absorption by the human body. It also supplements the functional components of tea, such as tea polyphenols, tea polysaccharides, caffeine, and tea proteins. Therefore, selenium-enriched tea is an ideal source of selenium supplementation. Regular consumption of selenium-enriched tea can improve the body's selenium intake and help prevent disease.

[0004] The participation of microorganisms in the migration and transformation of selenium in the environment is key to improving plant tolerance to selenium, efficiently absorbing and taking up selenium from the environment, and converting inorganic selenium into safe and effective organic selenium or other forms of selenium. Endophytes, as special microorganisms, are also widely involved in the migration and transformation of various elements in the environment. However, there are many types of endophytes, and the functions of different endophytes are closely related to their living environment and vary greatly. Screening selenium-resistant endophytes with selenium-reducing properties from the roots and leaves of tea trees in selenium-rich tea gardens can effectively improve the efficiency of tea trees in absorbing and transforming environmental selenium and increase the selenium content in tea leaves. Currently, no such endophytes have been reported, and the research and screening of such endophytes has important research and application value. Summary of the Invention

[0005] Based on the above technical problems, the present invention screens selenium-resistant strains from the endophytic bacteria in the roots and leaves of tea trees in selenium-rich tea gardens, identifies and classifies the screened strains, and further explores their functions and applications, aiming to obtain selenium-resistant endophytes with selenium-reducing ability, and provide more microbial resources for the preparation of selenium-rich products.

[0006] In one aspect, the present invention provides a fusiform lysinibacillus strain, which is named Lysinibacillus fusiformis GX7-1, and its deposit information is as follows:

[0007] Strain name: GX7-1;

[0008] Classification name: Lysinibacillus fusiformis;

[0009] Date of receipt by the depository: January 6, 2025;

[0010] Time of issuance of the preservation certificate: January 20, 2025;

[0011] Depository: China General Microbiology Center (CGMCC);

[0012] Deposit number: CGMCC No.33305.

[0013] Address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing.

[0014] Furthermore, the nucleotide sequence of 16S rDNA of the spindle-shaped Lysinibacillus is shown in SEQ ID NO: 1. The sequence of SEQ ID NO: 1 is as follows:

[0015]

[0016] In another aspect, the present invention provides a bacterial agent containing the Lysinibacillus fusiformis.

[0017] Furthermore, the bacterial agent of the fusiform Lysinibacillus contains one or more of the fermentation liquid of the fusiform Lysinibacillus or the bacterial cells of the fusiform Lysinibacillus.

[0018] Furthermore, in the bacterial agent, the spindle-shaped Lysinibacillus has at least one of the abilities of secreting IAA, producing siderophores, and fixing nitrogen.

[0019] In another aspect, the present invention provides a use of the fusiform Lysinibacillus in preparing selenium-containing products, wherein the fusiform Lysinibacillus reduces selenite in the environment to elemental nano-selenium.

[0020] Furthermore, the selenium-containing product is elemental nano-selenium particles.

[0021] Furthermore, the selenite is sodium selenite, and the concentration of the sodium selenite is not higher than 100 mM.

[0022] In another aspect, the present invention also provides use of the fusiform Lysinibacillus in reducing selenite.

[0023] Furthermore, the concentration of selenite is not higher than 100 mM.

[0024] Finally, the present invention also provides the use of the spindle-shaped Lysinibacillus in any one of producing IAA, producing siderophores and fixing nitrogen.

[0025] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects or advantages:

[0026] (1) The present invention screened out a selenium-resistant, selenium-reducing endophyte from the endophytic bacteria of tea trees in selenium-rich tea gardens. The strain was deposited in the General Microbiology Center of the China Culture Collection Administration, with the deposit number CGMCC No. 33305. The endophyte has the biological activity of secreting IAA and producing siderophores, and has nitrogen-fixing efficacy. It can be used in the production of IAA, siderophores and nitrogen fixation.

[0027] (2) Experimental results demonstrate that the fusiform Lysinibacillus fusiformis GX7-1 strain can tolerate 100 mM sodium selenite and exhibits selenium reduction activity. Its sodium selenite reduction efficiency was 73.29% at a sodium selenite concentration of 1 mM, and its nano-selenium production was 1.50 mM at a sodium selenite concentration of 5 mM. This strain is potentially applicable to selenite reduction-related fields and the preparation of nano-selenium. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a diagram showing the results of sample disinfection treatment.

[0029] Figure 2 This is the result of isolating endophytic bacteria from the roots and leaves of tea trees in a selenium-enriched tea garden.

[0030] Figure 3 This is the result of screening for selenium-tolerant selenium-reducing endophytes.

[0031] Figure 4 This is the phylogenetic tree of Lysinibacillus fusiformis GX7-1.

[0032] Figure 5 The selenium reduction efficiency and nano-selenium production of Lysinibacillus fusiformis GX7-1 under different selenite concentrations.

[0033] Figure 6 This is the scanning electron microscopy result of the reduction of nano-selenium by Lysinibacillus fusiformis GX7-1 when 5 mM selenite was added to the culture medium.

[0034] Figure 7 This is the energy dispersive spectrum analysis (EDX) result of the reduction of nano-selenium by Lysinibacillus fusiformis GX7-1 when 5 mM selenite was added to the culture medium.

[0035] Figure 8 This is a graph showing the siderophore production ability test results of Lysinibacillus fusiformis GX7-1;

[0036] Figure 9 This is a graph showing the nitrogen fixation ability test results of Lysinibacillus fusiformis GX7-1. DETAILED DESCRIPTION

[0037] The technical solutions of the present invention are described below with reference to the following embodiments; however, the present invention is not limited to the following embodiments.

[0038] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below with reference to specific embodiments and drawings, but the embodiments are not intended to limit the present invention.

[0039] The experimental methods and detection methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials are commercially available unless otherwise specified.

[0040] Example 1

[0041] This example is to isolate endophytic bacteria from the roots and leaves of tea trees in a selenium-enriched tea garden.

[0042] Sample source: The root and leaf samples of the tested tea trees were taken from the 'Shaancha No. 1' tea garden in Ankang City, Shaanxi Province.

[0043] Prepare LB solid medium: weigh 10 g of tryptone, 5 g of yeast extract, 10 g of sodium chloride, and 15 g of agar powder, dissolve them in distilled water, make up to 1 L with distilled water, and sterilize by autoclaving at 121°C for 21 min.

[0044] Prepare LB liquid medium: weigh 10 g of tryptone, 5 g of yeast extract, and 10 g of sodium chloride, dissolve them in distilled water, dilute to 1 L with distilled water, and sterilize under high pressure at 121°C for 21 min.

[0045] Isolation and purification of strains: The dilution spread plate method was used to isolate and purify endophytic bacteria in the roots and leaves of tea trees. The collected roots and leaves of tea trees were washed with clean water, and then the surface moisture was absorbed with filter paper for surface disinfection. The disinfection method is: first place the sample in 75% alcohol, soak, rinse and shake for 3 minutes, then pour out the alcohol, and then immerse in 3% sodium hypochlorite solution for 3 minutes, and finally rinse with sterile water 3 to 4 times. Absorb the last rinse liquid in the surface disinfection process and spread it on the LB plate, and culture it at 28°C for 1 to 3 days. If no microorganisms grow on the culture medium, it proves that the surface disinfection is thorough, and the results are as follows. Figure 1 As shown, it shows that the sample is thoroughly disinfected and can be used for subsequent strain isolation and purification.

[0046] The above disinfected samples (roots and leaves of tea tree) were added with 100 mL of sterile water and the roots and leaves were fully ground into a homogenate to prepare a suspension. 1 mL of the suspension was taken and mixed with 10 -1 , 10 -2 , 10 -3 , 10 -4 , 10 -5 Gradual dilution, take 100 μL of each gradient dilution solution and spread it on LB solid plate, culture at 37℃ for 2 days, the results are as follows Figure 2 shown.

[0047] A single colony was picked and purified three times using the plate streak method to obtain a pure culture of the strain. The strain was picked and stored in a refrigerator at 4°C.

[0048] Example 2

[0049] This example is to screen for selenium-resistant selenium-reducing endophytes.

[0050] Preparation of LB culture plates with different sodium selenite concentrations: Weigh 10 g of tryptone, 5 g of yeast extract, 10 g of sodium chloride, and 15 g of agar powder and dissolve them in distilled water. The volume is adjusted to 1 L with distilled water and sterilized at 121°C for 21 min to prepare LB solid culture medium. The prepared selenite mother solution is filtered and sterilized, and then added to the LB solid culture medium to prepare sodium selenite media with sodium selenite contents of 1 mM, 10 mM, 50 mM, and 100 mM, respectively. Before cooling, pour the plates to prepare LB culture plates with different sodium selenite concentrations.

[0051] Screening of selenium-tolerant strains: The strains isolated and purified in Example 1 and stored at 4°C were streaked and activated, and single colonies were picked and inoculated into liquid LB medium, shaken at 180 rpm and 28°C for 8 h, and the culture product was used as seed liquid. The seed liquid was added to the liquid LB medium and shaken to make the bacterial liquid OD 600 =0.8, dilute the original bacterial solution to obtain gradient diluted bacterial solution for use. The gradient diluted bacterial solution dilution degrees are 10 -1 , 10 -2 , 10 -3 , 10 -4 , 10 -5 2.5 μL of the original bacterial solution and the above-mentioned gradient diluted bacterial solution were respectively added to LB culture plates with different sodium selenite concentrations. Three replicates were set for each treatment. After the bacterial droplets were dried, the plates were inverted and cultured at 37°C. After 48 hours of culture, the color, size and number of the colonies were observed to determine the strain's tolerance to selenium. The results are as follows: Figure 3 As shown, the growth of the strain was not affected at a sodium selenite concentration of 100 mM, and the red colonies were identified as highly tolerant selenium-reducing bacteria, which were named GX7-1.

[0052] Example 3

[0053] This example is the identification of strain GX7-1.

[0054] The 16S rRNA gene of the selenium-resistant, reductive bacteria GX7-1 obtained by screening was amplified using universal bacterial PCR primers, and the PCR product was sequenced. The PCR primer sequences are as follows:

[0055] 27F:5'-AGAGTTTGATCCTGGCTCAG-3',

[0056] 1492R:5'-CGGCTACCTTGTTACGACTTC-3'.

[0057] PCR reaction system: 2.5 μL each of 5 μM upstream and downstream primers, 5 μL template DNA, 25 μL 2× Vazyme Lamp MasterMix, and ddH2O to 15 μL.

[0058] PCR reaction program: 94°C for 30 s; 94°C for 15 s, 55°C for 15 s, 72°C for 30 s, 30-35 cycles; 72°C for 2 min.

[0059] The PCR product was sent to a biotechnology company for sequencing, and the sequencing result is shown as SEQ ID NO: 1.

[0060] The sequencing results were subjected to BLAST on the NCBI website, and homologous sequences with high similarity were selected. The phylogenetic tree was constructed using MEGA11.0 software using the neighbor-joining method to determine the species category of the strain. Figure 4 The 16S rRNA gene sequence of strain GX7-1 was the most similar to that of Lysinibacillus fusiformis strain NBRC 15717(2), and they were clustered into one branch. This indicated that strain GX7-1 was Lysinibacillus fusiformis, and was named Lysinibacillus fusiformis GX7-1.

[0061] Example 4

[0062] This example is a test for the selenium reducing ability of Lysinibacillus fusiformis GX7-1.

[0063] A single colony of Lysinibacillus fusiformis GX7-1 (GX7-1) was selected and inoculated into LB liquid medium at 28°C and 180 rpm until OD 600 =0.8, take the above bacterial solution and inoculate it into LB liquid culture medium containing 1mM, 2.5mM, 5mM, 10mM, 15mM, and 20mM sodium selenite at a 0.1% (v / v) inoculation amount, and culture at 28°C and 180rpm for 48 hours.

[0064] Centrifuge the culture at 10,000 rpm for 8 minutes, remove the supernatant, and rinse three times with distilled water. Add 1M Na2S solution (pre-mixed) at a 1:2 ratio of volume to sample stock solution (pre-centrifugation volume). Mix thoroughly, incubate for 1 hour, and centrifuge again at 10,000 rpm for 3 minutes. The supernatant is then measured for absorbance at 500 nm. Each sample is measured in triplicate, with three replicates.

[0065] Accurately weigh 2.5mg, 5mg, 7.5mg, 10mg, and 12.5mg of elemental selenium powder into a test tube. Add 25mL of 1M Na2S solution to each tube and shake to fully dissolve. Use a Na2S solution without selenium powder as a control. Incubate for 1 hour and measure the absorbance at 500nm on a spectrophotometer. Repeat three times for each group. Draw a Se-Na2S standard curve.

[0066] The content of reduced elemental selenium was calculated using the standard curve, and the selenium reduction efficiency and yield were calculated using the formula.

[0067] Selenium reduction efficiency = amount of elemental selenium after reduction / amount of selenium added to Na2SeO3 × 100%

[0068] The reduction efficiency and nano-selenium production of Lysinibacillus fusiformis GX7-1 at different sodium selenite concentrations were calculated. Figure 5 As shown, Lysinibacillus fusiformis GX7-1 can reduce sodium selenite to nano-selenium at relatively low concentrations. At a sodium selenite concentration of 1 mM, Lysinibacillus fusiformis GX7-1 achieved a reduction efficiency of 73.29%, the highest for sodium selenite. At a sodium selenite concentration of 5 mM, the reduction efficiency reached 30.16%, with the highest nano-selenium yield at 1.50 mM.

[0069] Example 5

[0070] This example is the characterization and analysis of bio-nanoselenium synthesized by Lysinibacillus fusiformis GX7-1.

[0071] Lysinibacillus fusiformis GX7-1 (OD 600=0.8) was inoculated at a 0.1% (v / v) inoculum into sterilized LB liquid medium containing 5 mM sodium selenite and cultured at 28°C, 180 rpm, for 48 h. The shake-cultured red bacterial liquid was centrifuged at 10,000 rpm for 8 min at room temperature, the supernatant removed, and the pellet resuspended in physiological saline and rinsed three times by centrifugation to form the sample bacterial liquid.

[0072] A coverslip with a side length of less than 7 mm was placed in the sample solution. After the sample adhered to the coverslip, it was fixed with 2 mL of 5% by volume glutaraldehyde and incubated at 4°C overnight. The sample was then rinsed two to three times with 2 mL of 0.1 M PBS buffer (pH 7.2) for 10 minutes each. The sample was then rinsed once with 30%, 50%, 70%, 80%, and 90% ethanol for 10 minutes each, and twice with 100% ethanol for 10 minutes each. Finally, the sample was replaced with 1 mL of isoamyl acetate for 10 minutes. The sample was dried and observed and photographed using a field emission scanning electron microscope (FESEM, S-4800). The nanoparticles were analyzed using an energy dispersive spectrometer (EDX).

[0073] The results are as follows Figure 6 As shown in the figure, under the scanning electron microscope, a large number of spherical particles were clearly seen outside the spindle-shaped Lysinibacillus fusiformis GX7-1. Figure 7 As shown in the figure, the outer particles of Lysinibacillus fusiformis GX7-1 showed a characteristic absorption peak of selenium at 1.37keV. These results indicate that Lysinibacillus fusiformis GX7-1 can reduce sodium selenite to produce red elemental selenium nanoparticles.

[0074] Example 6

[0075] This example is a growth promotion test of Lysinibacillus fusiformis GX7-1.

[0076] (1) IAA production capacity test of Lysinibacillus fusiformis GX7-1

[0077] Prepare nitrogen-containing culture medium: weigh 0.5 g yeast extract, 10 g glucose, 1.0 g (NH4)2SO4, 2 g K2HPO4, 0.5 g MgSO4·7H2O, and 0.1 g NaCl and dissolve them in distilled water. Then dilute to 1 L with distilled water and adjust the pH to 7.2-7.4.

[0078] Prepare Salkowski colorimetric reagent: measure 1 mL of 0.5 M FeCl3 and 50 mL of 35% HClO4 and mix them well.

[0079] Lysinibacillus fusiformis strain GX7-1 was inoculated at a 1% inoculum into a nitrogen-containing medium supplemented with 0.2 g / L tryptophan and incubated on a shaker at 28°C, 180 rpm, for 48 hours. The culture was centrifuged at 10,000 rpm for 10 minutes, and the supernatant was mixed with an equal volume of Salkowski reagent. Positive and negative controls were also set up: the positive control consisted of 800 μL of a 100 mg / L IAA standard solution and an equal volume of Salkowski reagent colorimetric solution, while the negative control consisted of 800 μL of nitrogen-containing medium and an equal volume of Salkowski reagent colorimetric solution. The reaction was allowed to proceed at room temperature in the dark for 30 minutes, and the results were observed. A positive result, indicated by a pink color, indicates that the strain is capable of secreting IAA; a darker pink indicates a higher IAA secretion capacity. A negative result, indicated by a color consistent with the negative control (the color of the culture medium), indicates that the strain is incapable of secreting IAA. The test result shows pink, indicating that Lysinibacillus fusiformis GX7-1 has the ability to produce IAA.

[0080] (2) Phosphate solubilization ability test of Lysinibacillus fusiformis GX7-1

[0081] Prepare inorganic phosphorus solid culture medium: weigh 0.5 g yeast extract, 10 g glucose, 5 g tricalcium phosphate, 0.5 g (NH4)2SO4, 0.2 g KCl, 0.1 g MgSO4, 0.1 mg MnSO4, 0.1 mg FeSO4, and 15 g Agar, dissolve them in distilled water, and then dilute to 1 L with distilled water.

[0082] Prepare organophosphorus solid culture medium: weigh 10 g of glucose, 0.5 g of ammonium sulfate, 0.3 g of NaCl, 0.3 g of MgSO4, 0.03 g of MnSO4, 0.3 g of K2SO4, 0.03 g of ferrous sulfate, 5 g of calcium phosphate, 0.2 g of lecithin, and 15 g of Agar, dissolve them in distilled water, and then dilute to 1 L with distilled water.

[0083] Lysinibacillus fusiformis GX7-1 was inoculated into LB liquid medium and cultured until OD 600=0.8, then the cultured bacterial liquid was spotted on an inorganic phosphorus solid culture medium and cultured in the dark at 28°C for 7 days. The results showed that a transparent phosphate-solubilizing ring appeared around the colony, indicating that the strain had the ability to solubilize phosphate. No phosphate-solubilizing ring appeared around the spindle-shaped lysine Bacillus Lysinibacillus fusiformis GX7-1, indicating that it did not have the ability to solubilize phosphate.

[0084] (3) Detection of the siderophore production capacity of Lysinibacillus fusiformis GX7-1

[0085] Prepare CAS assay medium: weigh 0.0729 g of HDTMA, 0.0605 g of CAS, 0.3 g of sodium dihydrogen phosphate dihydrate, 1.2135 g of disodium hydrogen phosphate dodecahydrate, 0.125 g of ammonium chloride, 0.0375 g of potassium dihydrogen phosphate, 0.0625 g of sodium chloride, 0.003 g of FeCl3·6H2O, and 9 g of Agar, dissolve them in distilled water, and then dilute to 1 L with distilled water.

[0086] Lysinibacillus fusiformis GX7-1 was inoculated onto CAS medium and cultured in a 28°C incubator for 7 days. The results were observed. If a yellow halo appeared around the strain, it indicated that the strain had the ability to produce the vector. Figure 8 As shown, the results showed that Lysinibacillus fusiformis GX7-1 has the ability to produce siderophores.

[0087] (4) Nitrogen fixation ability test of Lysinibacillus fusiformis GX7-1

[0088] Prepare Ashby solid medium: weigh 10 g of mannitol, 0.2 g of KH2PO4, 0.2 g of MgSO4·7H2O, 0.2 g of NaCl, 0.1 g of CaSO4·2H2O, 5 g of CaCO3, and 20 g of agar powder, dissolve them in ddH2O, and make up to 1 L with ddH2O. Adjust the pH to 7.4.

[0089] The Lysinibacillus fusiformis GX7-1 strain was inoculated on Ashby solid medium and cultured at 28℃ for 2 days. The strain was picked and inoculated three times to observe the growth of the strain. The results are as follows: Figure 9As shown, the strain Lysinibacillus fusiformis GX7-1 can grow normally, indicating that the strain Lysinibacillus fusiformis GX7-1 has the ability to fix nitrogen.

[0090] Example 7

[0091] This example is about optimizing the inoculum amount of Lysinibacillus fusiformis GX7-1.

[0092] LB liquid medium containing 5 mM sodium selenite was prepared and inoculated with Lysinibacillus fusiformis GX7-1 at inoculum sizes of 4%, 6%, and 8% by volume. The culture was incubated at 28°C, 180 rpm, and the bacterial cell weight (wet weight) was measured after centrifugation. The results are shown in Table 1. The results show that among the cells produced by culturing Lysinibacillus fusiformis GX7-1 at inoculum sizes of 4% to 10% by volume, the cell weight obtained at an inoculum size of 6% was the highest, indicating that an inoculum size of 6% by volume was the optimal inoculum size for Lysinibacillus fusiformis GX7-1.

[0093] Table 1 Determination of wet weight of cells of Lysinibacillus fusiformis GX7-1 fermented with different inoculation amounts in volume percentage

[0094] Test items Inoculation rate 4% Inoculation rate 6% Inoculation rate 8% Inoculation amount 10% Wet weight of bacteria (g) 0.102 0.148 0.136 0.128

[0095] Example 8

[0096] This example is about preparing a bacterial agent of Lysinibacillus fusiformis GX7-1.

[0097] Cultivation of spindle-shaped lysinibacillus GX7-1: Activating the preserved spindle-shaped lysinibacillus GX7-1 strain, inoculating the activated spindle-shaped lysinibacillus GX7-1 into LB liquid culture medium, culturing at 28° C., 180 rpm, and culturing for 24 hours to prepare a seed culture solution; inoculating the prepared seed culture solution into the LB liquid culture medium at an inoculum size of 6% by volume, culturing at 28° C., 180 rpm, and culturing for 24 hours to prepare a selenium-enriched fermentation liquid.

[0098] Preparation of liquid inoculum: The selenium-enriched fermentation broth prepared in Example 8 was diluted with sterile water at ratios of 1:1, 1:10, and 1:100, and then aseptically filled to prepare a liquid inoculum of Lysinibacillus fusiformis GX7-1.

[0099] Preparation of powdered bacterial agent: The selenium-enriched fermentation broth prepared in Example 8 was centrifuged at 10,000 rpm for 10 min, the supernatant was discarded, and the bacterial pellet at the bottom was retained. 5% of a protective agent was added and freeze-dried using a freeze dryer. The freeze-dried powder was collected to prepare a freeze-dried powder of Lysinibacillus fusiformis GX7-1.

[0100] As described above, the basic principles, main features and advantages of the present invention are well described. The above embodiments and descriptions are merely descriptions of preferred embodiments of the present invention, and the present invention is not limited to the above embodiments. Various changes and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit and scope of the present invention should fall within the scope of protection determined by the present invention.

Claims

1. A strain of Lysinibacillus spindle-shaped, characterized in that: The spindle-shaped lysinibacillus is named Lysinibacillus fusiformis GX7-1 and is deposited in the General Microbiology Center of China Culture Collection Administration of Microorganisms with a deposit number of CGMCC No. 33305.

2. A bacterial agent containing the Lysinibacillus fusiformis according to claim 1.

3. The microbial agent according to claim 2, characterized in that The bacterial agent contains one or more of the fermentation liquid of lysinophilic Bacillus or the bacterial cells of lysinophilic Bacillus.

4. The microbial agent according to claim 2, characterized in that The fusiform Lysinibacillus has at least one of the abilities of secreting IAA, producing siderophores and fixing nitrogen.

5. The use of the lysinibacillus fusiformis according to claim 1 in the preparation of selenium-containing products, characterized in that: The fusiform Lysinibacillus reduces selenite in the environment into nano-selenium.

6. The use according to claim 5, wherein the selenium-containing product is elemental nano-selenium particles.

7. The use according to claim 5, wherein the selenite is sodium selenite, and the concentration of the sodium selenite is not higher than 100 mM.

8. Use of the lysinibacillus fusiformis according to claim 1 in reducing selenite.

9. The use according to claim 8, characterized in that The concentration of selenite is no higher than 100 mM.

10. Use of the lysinophilic Bacillus according to claim 1 in any one of IAA production, siderophore production and nitrogen fixation.

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