Peanut rhizosphere non-symbiotic nitrogen-fixing bacteria and application thereof

Abstract

The invention discloses a peanut rhizosphere non-symbiotic nitrogen-fixing bacterium and application thereof. The peanut rhizosphere non-symbiotic nitrogen-fixing bacterium is classified and named as Kosakonia sp., the preservation number is CGMCC (China General Microbiological Culture Collection Center) NO.34137, and the peanut rhizosphere non-symbiotic nitrogen-fixing bacterium is preserved in the China General Microbiological Culture Collection Center. The strain has strong nitrogen fixation and growth promotion functions at peanut rhizosphere; the peanut rhizobium strain can coexist with rhizobium, has no antagonism, and can be combined with efficient peanut rhizobium to further improve the nitrogen fixation capacity of peanuts and effectively increase the yield of peanuts. The strain has potential popularization and application values in the peanut planting industry.

Description

Technical Field

[0001] The invention belongs to the technical field of microbial agriculture, and particularly relates to non-symbiotic nitrogen-fixing bacteria in the peanut rhizosphere and applications thereof. Background Art

[0002] Nitrogen is one of the three essential nutrients for plant growth and the only major plant nutrient that is fixed from the air. Nitrogen fixation occurs primarily through industrial and biological methods. Industrial nitrogen fixation consumes significant amounts of coal. Producing one ton of nitrogen fertilizer consumes 2.8 tons of standard coal and emits 8.2 tons of carbon dioxide, resulting in high energy consumption and even contributing to climate change. Furthermore, less than 50% of applied fertilizer is absorbed by crops, with the majority lost to soil and rivers, causing serious environmental problems.

[0003] Peanuts, an annual herbaceous plant in the leguminous family, are a significant source of edible vegetable oil and plant protein, making them the leading of my country's eight major oilseed crops. my country ranks second in the world in peanut cultivation area, and first in both total peanut production and yield per unit area. The peanut industry contributes significantly to my country's agricultural economy.

[0004] Peanuts can form nodules with rhizobia to symbiotically fix nitrogen, providing approximately half of the peanut's nitrogen needs. This symbiotic nitrogen fixation provides a highly competitive, environmentally friendly, and sustainable nitrogen fertilizer. Although non-rhizobium nitrogen-fixing bacteria exist within the peanut rhizosphere and nodules, international research and application of peanut nitrogen-fixing bacteria has long focused on efficient rhizobia. The contribution of non-rhizobium nitrogen-fixing bacteria to peanut nitrogen fixation has been overlooked, resulting in a significant lack of resource development and application evaluation. The diversity, nitrogen-fixing capacity, and potential of these nitrogen-fixing bacteria are rarely reported. Peanut production is primarily focused on yield and quality, with less attention paid to nodulation ability. This has resulted in many new peanut varieties experiencing inefficient or even non-nodulation, leading to nitrogen deficiencies and reduced yields. Improving non-nodulation nitrogen-fixing capacity in peanuts through inoculation with non-symbiotic nitrogen-fixing bacteria could not only compensate for the deficiencies in nodulation in efficient nodulation varieties but also offer new hope for effectively improving nitrogen-fixing capacity in inefficient or non-nodulating peanuts. Summary of the Invention

[0005] In view of the deficiencies in the above-mentioned prior art, the present invention provides a peanut rhizosphere non-symbiotic nitrogen-fixing bacterium and its application.

[0006] The specific technical solutions are as follows:

[0007] One of the purposes of the present invention is to provide a peanut rhizosphere non-symbiotic nitrogen-fixing bacterium, which is classified and named Kosakonia sp., with a preservation number of CGMCC NO.34137, and is deposited in the General Microbiology Center of China Microorganism Culture Collection Administration.

[0008] The strain was isolated from the experimental field of the Agricultural Science Research Institute in Fushan District, Yantai City, Shandong Province. The colonies are round, moist, raised in the middle, with neat edges, milky white and translucent, do not produce spores, have a high exopolysaccharide content, and are Gram-negative. After extracting the genomic DNA of the bacteria, sequence analysis was performed on it. Comparison with GenBank revealed that the 16S rRNA gene sequence amplified by the bacteria of the present invention is consistent with that of Kosakonia sacchari SP1 T The highest similarity was 99% with the strain (Accession No.: NR 118333). The isolated bacterium was named Kosakonia sp. YTU00262.

[0009] The whole genome DNA sequence of the fungus was further determined, and a species tree of all typical fungi of the genus was constructed based on the whole genome sequence (such as Figure 1 This bacterium is similar to Kosakonia sacchari SP1 T The average nucleotide identity (ANI) values of the whole genome between YTU00262 and other strains were further calculated, and the results showed that it had a close relationship with Kosakoniasacchari SP1. T The highest ANI value among the strains was 93.0%, while the simulated DNA-DNA hybridization value was 36%. This is lower than the classification criteria set by the International Committee on Systematic Taxonomy for bacterial species: ANI values of 94% to 95% and DNA-DNA hybridization values of 70% are considered the same species. Therefore, strain YTU00262 is a potential new species of the genus Kosakonia.

[0010] Experiments have confirmed that the strain Kosakonia sp. YTU00262 has a strong nitrogen-fixing capacity, with a nitrogenase activity of up to 1369 nmol C₂H₄ / (mg protein·h). Inoculation with this strain significantly promotes peanut growth and provides nitrogen for the plant. This strain can coexist with rhizobia without antagonism. Inoculation with a high-efficiency, non-symbiotic nitrogen-fixing bacteria-peanut rhizobium complex during peanut cultivation can fix nitrogen in the rhizosphere of peanuts with varying nodulation abilities without affecting rhizobia nodulation and nitrogen fixation, further increasing the amount of nitrogen fixed in the peanuts.

[0011] The second purpose of the present invention is to provide the application of the above-mentioned peanut rhizosphere non-symbiotic nitrogen-fixing bacteria in promoting plant growth. Specifically, it is used to improve the nitrogen fixation ability of plants. In particular, when the above-mentioned peanut rhizosphere non-symbiotic nitrogen-fixing bacteria are used in combination with rhizobia, the nitrogen fixation ability of plants can be significantly improved. In the experiment, the present invention inoculated a non-symbiotic nitrogen-fixing bacteria-peanut rhizobium composite bacterial agent and sprayed it on peanut seeds and surrounding soil during sowing. It can effectively increase the yield of peanuts with different nodulation abilities. Compared with the single rhizobium inoculation group, the yield of high-efficiency nodulation and low-efficiency nodulation peanuts increased by 18.00% and 13.57%, respectively.

[0012] Furthermore, the plant is preferably a leguminous plant, especially peanut.

[0013] A third object of the present invention is to provide the use of the peanut rhizosphere non-symbiotic nitrogen-fixing bacteria in agricultural microbial agents. The peanut rhizosphere non-symbiotic nitrogen-fixing bacteria of the present invention can be used in agricultural microbial agents as growth promoters or nitrogen nutrition improvers.

[0014]

Biological Deposit Instructions

[0015] China General Microbiology Culture Collection Center registration number: CGMCCNO.34137;

[0016] Reference biological material (strain): YTU00262;

[0017] The biological material (strain) requested for deposit is accompanied by a proposed taxonomic name: Kosakonia sp.;

[0018] This biological material (strain) was received and registered by the General Microbiology Center of the China Culture Collection Administration on April 8, 2025.

[0019] Address of the Collection Center: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing.

[0020] The beneficial effects of the present invention are as follows:

[0021] This study isolated a non-symbiotic peanut rhizosphere nitrogen-fixing bacterium, Kosakonia sp. YTU00262, which has a strong nitrogen-fixing and growth-promoting function in the peanut rhizosphere. It can coexist with rhizobia without antagonism. When used in combination with high-efficiency peanut rhizobia, it can further enhance the nitrogen-fixing capacity of peanuts and effectively increase peanut yield. This bacterium has potential application value in the peanut cultivation industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The species tree for the typical bacteria of the genus Cossackia;

[0023] Figure 2Comparative photos of peanut plants in the control group inoculated with sterile water and the experimental group inoculated with strain YTU00262 in Example 2;

[0024] Figure 3 Comparison of aboveground fresh weight, aboveground dry weight, underground dry weight, and plant chlorophyll SPAD of peanuts in the control group inoculated with sterile water and the experimental group inoculated with strain YTU00262 in Example 2;

[0025] Figure 4 The results of the antagonistic ability analysis experiment between non-symbiotic nitrogen-fixing bacteria and peanut rhizobia in Example 3 are as follows;

[0026] Figure 5 Comparative photos of peanut plants in Example 3, a control group inoculated with Rhizobium YTU21284 and sterile water, and an experimental group inoculated with a mixed bacterial solution;

[0027] Figure 6 Comparison of aboveground fresh weight, aboveground dry weight, and leaf chlorophyll SPAD value of peanuts in the control group inoculated with rhizobium YTU21284 and sterile water and the experimental group inoculated with the mixed bacterial solution in Example 3;

[0028] Figure 7 These are the experimental results of inoculating sterile water, rhizobia, and the composite bacterial agent in farmland in Example 4. DETAILED DESCRIPTION

[0029] The principles and features of the present invention are described below with reference to examples. The examples are only used to explain the present invention and are not used to limit the scope of the present invention.

[0030] Example 1 Obtaining strain Kosakonia sp. YTU00262 and evaluating its nitrogen fixation ability

[0031] 1. Collection and screening:

[0032] In the experimental field of Yantai Academy of Agricultural Sciences in Fushan District, Yantai City, Shandong Province, different varieties of peanuts, including Xuhua No. 9, Shanyou 523, and Yuanza 9307, were planted. During the flowering and needle-setting period of peanuts, rhizosphere soil samples of different varieties of peanuts were collected. 5 g of soil was weighed and placed in a 100 mL conical flask. 50 mL of sterile PBS buffer solution (0.01 mol / L) was added and shaken at 160 rpm for 30 min. The supernatant was collected and the soil suspension was diluted in a 10-fold volume gradient to obtain 10 -1 ~10 -9 Gradient soil suspension.

[0033] Take 0.1 mL of each sample at different concentration gradients and spread it onto a nitrogen-free solid culture medium (20 g sucrose, 0.01 g NaCl, 0.01 g FeCl3, 0.2 g MgSO4·7H2O, 0.1 g K2HPO4, 0.4 g KH2PO4, 0.002 g Na2MoO4·2H2O, 15–25 g agar, and dilute to 1 L with distilled water). Set up three replicates for each concentration gradient. Incubate the plate upside down in a 30°C incubator for 7 days. Once a single colony grows, streak it with an inoculating loop and incubate it at 30°C for 3–7 days. Repeat the streak purification process 2–3 times until a pure culture is obtained.

[0034] The obtained pure culture was placed in 20% glycerol (v / v) and stored in a -80°C ultra-low temperature freezer.

[0035] 2. Identification of bacterial species:

[0036] After extracting the genomic DNA of the bacterium, PCR primers 27F and 1492R were used for amplification. The nucleotide sequence of 27F is shown in SEQ ID NO.1, and the nucleotide sequence of 1492R is shown in SEQ ID NO.2. The specific primer sequences are shown in Table 1. The PCR products were sequenced and sequence analysis was performed. Comparison with GenBank showed that the 16S rRNA gene sequence amplified by the strain of the present invention was consistent with that of Kosakonia sacchari SP1 T The highest similarity was 99% with the strain (Accession No. NR 118333). The isolated bacterium was named Kosakonia sp. YTU00262. The DNA nucleotide sequence of the 16S rRNA gene of Kosakonia sp. YTU00262 is shown in SEQ ID NO. 3.

[0037] Table 1 Primers for 16S rRNA gene amplification

[0038] Primers Serial number Nucleotide sequence 27F SEQ ID NO.1 5'-AGAGTTTGATCMTGGCTCAG-3' 1492R SEQ ID NO.2 5'-GGTTACCTTGTTACGACTT-3'

[0039] The whole genome DNA sequence of the fungus was further determined, and a species tree of all typical fungi of the genus was constructed based on the whole genome sequence (such as Figure 1 This bacterium is similar to Kosakonia sacchari SP1 T The average nucleotide identity (ANI) values of the whole genome between YTU00262 and other strains were further calculated, and the results showed that it had a close relationship with Kosakoniasacchari SP1. TThe highest ANI value among the strains was 93.0%, while the simulated DNA-DNA hybridization value was 36%. This is lower than the classification criteria set by the International Committee on Systematic Taxonomy for bacterial species: ANI values of 94% to 95% and DNA-DNA hybridization values of 70% are considered the same species. Therefore, strain YTU00262 is a potential new species of the genus Kosakonia.

[0040] The strain was biologically preserved and named Kosakonia sp. with a preservation number of CGMCC NO.34137. It was deposited in the General Microbiology Center of China Culture Collection Administration of Microorganisms.

[0041] 3. Initial screening of nitrogen-fixing ability of strains:

[0042] The purified strains were inoculated into test tubes containing 10 mL of nitrogen-free liquid culture medium, shaken at 140 rpm for 5 days, and the OD value of the bacterial solution was measured. Those that could grow in the culture medium were preliminarily judged to be non-symbiotic nitrogen-fixing bacteria.

[0043] The genomic DNA extracted in step 2 was then used as a template for amplification using primers nifHF and nifHR. The nucleotide sequence of nifHF is shown in SEQ ID NO. 4, and the nucleotide sequence of nifHR is shown in SEQ ID NO. 5. The primer sequences are shown in Table 2. Strains that test positive for nitrogen-fixing genes and grow well in nitrogen-free liquid culture medium are identified as non-symbiotic diazotrophs. The entire genome of these strains contains all the genes necessary for nitrogen fixation, such as nifHDK.

[0044] Table 2 Primers for nifHDK gene amplification

[0045] Primers Serial number Nucleotide sequence nifHF SEQ ID NO.4 5'-TGCGAYCCSAARGCBGACTC-3' nifHR SEQ ID NO.5 5'-ATSGCCATCATYTCRCCGGA-3'

[0046] 4. Evaluation of nitrogen fixation ability of non-symbiotic nitrogen-fixing bacteria:

[0047] The non-symbiotic nitrogen-fixing bacteria were inoculated into TSB medium, cultured to the exponential phase, inoculated into nitrogen-free medium, and adjusted to OD 600 =1.0, 1.5 mL of bacterial suspension was inoculated into a 9 mL serum bottle. 0.7 mL of acetylene (C₂H₄) gas was pumped in using a pump. To ensure pressure equilibrium in the serum bottle, the corresponding volume of gas was aspirated with a syringe before acetylene was injected. The serum bottle was inverted and incubated in a 30°C incubator for 2 hours. Gas was sampled using a weighing sampler, and the acetylene and ethylene (C₂H₂) contents were determined by gas chromatography, and the nitrogenase activity was calculated. Strain YTU00262 was determined to have the highest nitrogen fixation capacity, at 1369 nmol C₂H₄ / (mg protein·h), indicating high nitrogenase activity.

[0048] Example 2: Greenhouse pot experiment evaluating the nitrogen fixation ability of strain YTU00262 and peanut

[0049] Strain YTU00262 was inoculated into TSB medium and cultured at 28°C and 150 rpm on a shaker for 1 to 2 days until the logarithmic growth phase. The cells were collected after centrifugation at 12000 g for 2 minutes and diluted with PBS to an OD 600 =0.2(about 10 8 CFU / mL).

[0050] Select intact, uniformly sized peanut seeds (high-efficiency nodulation peanut: Huayu 20). Disinfect the surface of the seeds by soaking them in 95% ethanol for 30 seconds, then in 3% NaClO solution for 5 minutes, and finally rinse them 7-8 times with sterile water. After disinfection, place the seeds evenly on a 0.6% water agar medium and incubate them in the dark at 28°C for 3 days. Wait until the seeds develop radicles before use.

[0051] To plant peanuts, sterilize the peanut pots and vermiculite (soaked in a low-nitrogen nutrient solution). Place the sterilized vermiculite in the pots and plant germinated peanut seeds (radicle length 2-3 cm) in the pots. One seed per pot is inoculated with 1 mL of bacterial solution next to the seed. Five replicates are set up as the experimental group. A control group is also inoculated with sterile water. The pots are then sealed with plastic wrap and incubated in a greenhouse at 26°C with 16 hours of light per day for 45 days.

[0052] After inoculation and cultivation, the peanut plants of the control group inoculated with sterile water and the experimental group inoculated with strain YTU00262 were compared in the following photos: Figure 2 After inoculation and cultivation, the plant height, chlorophyll content, above-ground fresh weight, dry weight and other indicators of peanuts were counted. The results are shown in Figure 3 .like Figure 3 As shown, the aboveground fresh weight, aboveground dry weight, underground dry weight, and plant chlorophyll SPAD of peanut increased by 21.6%, 37.2%, 30.0%, and 18.2%, respectively, indicating that strain YTU00262 can significantly promote the growth of peanuts and provide nitrogen for peanuts. Figure 2 、 Figure 3 Middle: CK is the control group inoculated with sterile water, and YTU00262 is the experimental group inoculated with strain YTU00262.

[0053] The statistical analysis of the results showed that strain YTU00262 had a good nitrogen fixation and growth-promoting function.

[0054] Example 3 Greenhouse experiment of co-inoculation of non-symbiotic nitrogen-fixing bacteria and rhizobia

[0055] The antagonistic ability of non-symbiotic nitrogen-fixing bacteria and peanut rhizobia was analyzed. Peanut rhizobia (Bradyrhizobium sp. YTU21284, a highly efficient peanut rhizobium from the School of Life Sciences of Yantai University) and non-symbiotic nitrogen-fixing bacteria YTU00262 were inoculated onto TSA culture medium, with a 0.6 cm interval between the two colonies, and cultured for 3 days. The experimental results are shown in Figure 4 , indicating that there was no antagonism between the two bacteria. Figure 4 In the figure, A, B, and C are three parallel experimental groups. In each group, the left side is rhizobium YTU21284, and the right side is non-symbiotic nitrogen-fixing bacteria YTU00262.

[0056] Peanut rhizobium YTU21284 and non-symbiotic nitrogen-fixing bacteria YTU00262 were inoculated into TSB medium and cultured at 28°C with a shaker at 150 rpm for 2-3 days until the logarithmic growth phase. The cells were harvested by centrifugation at 12,000 g for 2 minutes and diluted with PBS to an OD of 0.2. A 1:1 (v / v) ratio of peanut rhizobium to non-symbiotic nitrogen-fixing bacteria was used.

[0057] Select intact, uniformly sized peanut seeds (high-nodulation peanut: Huayu 20; low-nodulation peanut: Yuanza 9307). Disinfect the surface of the seeds by soaking them in 95% ethanol for 30 seconds, then in 3% NaClO solution for 5 minutes, and finally rinse them 7–8 times with sterile water. After disinfection, place the seeds evenly on a 0.6% water agar medium and incubate them in the dark at 28°C for 3 days. Wait until the seeds develop radicles before use.

[0058] Peanut planting was carried out by sterilizing peanut pots and vermiculite (soaked in a low-nitrogen nutrient solution). The sterilized vermiculite was placed in the pots, and germinated peanut seeds (radicle length 2-3 cm) were planted in the pots. One seed per pot was inoculated next to the seed with 1 mL of a mixed solution of peanut rhizobia and non-symbiotic nitrogen-fixing bacteria. Five replicates were used for each peanut variety. A positive control was inoculated with 1 mL of rhizobium YTU21284, while a negative control was inoculated with 1 mL of sterile water. The pots were then sealed with plastic wrap and randomly placed in a greenhouse at 26°C with 16 hours of light per day for 45 days.

[0059] After inoculation and cultivation, the peanut plants in the control group inoculated with rhizobium YTU21284 and sterile water and the experimental group inoculated with mixed bacterial solution are compared in the following photos: Figure 5 . Figure 5 Middle: a is a photo of the high-efficiency nodulation peanut Huayu 20, b is a photo of the low-efficiency nodulation peanut Yuanza 9307, CK is the negative control group inoculated with sterile water, Rhizobium is the positive control group inoculated with peanut rhizobium YTU21284, and double inoculation is the experimental group inoculated with a mixed bacterial solution of peanut rhizobia and non-symbiotic nitrogen-fixing bacteria.

[0060] After inoculation and cultivation, the peanut plant height, chlorophyll content, aboveground fresh weight, aboveground dry weight and other indicators were counted. The results are as follows: Figure 6 shown. Figure 6 Middle: A to C are the indicators of the high-efficiency nodulation peanut Huayu 20, D to F are the indicators of the low-efficiency nodulation peanut Yuanza 9307; CK is the negative control group inoculated with sterile water, YTU21284 is the positive control group inoculated with peanut rhizobium YTU21284, and double inoculation is the experimental group inoculated with a mixed bacterial solution of peanut rhizobia and non-symbiotic nitrogen-fixing bacteria. Figure 6 As shown, compared with the rhizobium inoculated group, the aboveground fresh weight, aboveground dry weight and leaf chlorophyll SPAD value of the double-inoculated high-efficiency nodulation peanut Huayu 20 increased by 23%, 7% and 7%, respectively, and the aboveground fresh weight, aboveground dry weight and leaf chlorophyll SPAD value of the double-inoculated low-efficiency nodulation peanut Yuanza 9307 increased by 8%, 23% and 15%, respectively.

[0061] The statistical analysis of the above results showed that double inoculation of peanut rhizobia and non-symbiotic nitrogen-fixing bacteria effectively promoted the growth of peanuts with different nodulation abilities.

[0062] Example 4: Application test of co-inoculation of non-symbiotic nitrogen-fixing bacteria and rhizobia in farmland

[0063] Rhizobium YTU21284 and non-symbiotic nitrogen-fixing bacteria YTU00216 were inoculated into TSB medium and cultured in a shaker at 28°C and 150 rpm until the end of the logarithmic growth phase. The two bacterial cultures were mixed in a 1:1 (v / v) ratio to prepare a composite inoculum for inoculation.

[0064] Plant peanuts. The planting period is from early June to the end of September. Level the land and make ridges with a width of 30 to 35 cm, a height of 20 to 25 cm, and a spacing of 70 cm between ridges.

[0065] Pick peanut seeds with full grains and uniform size (high-efficiency nodulation peanuts: Huayu 20; low-efficiency nodulation peanuts: Yuanza 9307), pour the fungicide into the peanut seeds in a cool and sunny place, and dry them in a cool place.

[0066] Sowing was performed using a seed drill or by hand onto ridges, with a plant spacing of 35 cm and a depth of 5 cm. The negative control group received no inoculation, the positive control group received only rhizobia, and the experimental group received a combination of inoculations. Each group received 1.5 kg of superphosphate and 8.0 kg of potassium sulfate per mu. The negative control group also received 4.8 kg of urea per mu as nitrogen fertilizer. After sowing, the ground was covered with film to retain heat, moisture, and control weeds. The control and experimental groups maintained the same plant spacing, sowing depth, and management practices.

[0067] For field management, after peanut seedlings emerge, the film should be removed and the seedlings planted promptly. Peanuts are sensitive to both drought and waterlogging, so a soil moisture content of 60% is ideal. Watering and drainage should be done regularly based on rainfall. During the flowering and spiking period, large numbers of fruit spiking fruit will gradually enter the soil. Check and remove the film promptly to prevent difficulties in spiking fruit and a low fruiting rate. Pest and disease control and weed removal are also essential.

[0068] When the lower leaves turn yellow and fall off, most pods harden, and the seeds are full, they are harvested in time. When harvested, they are weighed and dried in time, and the fresh weight and dry weight of the peanut fruits are statistically analyzed. Figure 7 . Figure 7 Middle: CK is inoculated with sterile water, YTU21284 is inoculated with peanut rhizobium YTU21284, and YTU21284+YTU00216 is a composite agent inoculated with peanut rhizobium YTU21284 and non-symbiotic nitrogen-fixing bacteria YTU00216. Figure 7 As can be seen, compared with sterile water inoculation, both rhizobium and composite inoculation showed a better growth-promoting effect, with the composite inoculation being more effective. For the highly efficient nodulating peanut (Huayu 20), after inoculation with the composite inoculation, the number of peanut pods increased by 14.06%, the weight of 100 peanut pods increased by 1%, and the yield increased by 18% compared to the group inoculated with the highly efficient rhizobium. For the low-efficiency nodulating peanut (Yuanza 9307), the number of peanut pods increased by 9.36%, the weight of 100 peanut pods increased by 1.06%, and the yield increased by 13.57% compared to the group inoculated with the highly efficient rhizobium. After inoculation with the composite inoculation, the yield of both peanut varieties was significantly higher than that of the group inoculated with rhizobia alone.

[0069] Therefore, the strain YTU00216 of the present invention can significantly promote the number of pods of peanuts with different nodulation abilities in peanut cultivation applications, thereby achieving the purpose of significantly increasing production; its application and promotion in peanut cultivation can effectively reduce production costs, increase crop yields, and promote the sustainable development of agriculture.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Non-symbiotic nitrogen-fixing bacteria in the peanut rhizosphere, characterized in that Its classification name is Kosakonia sp., the preservation number is CGMCC NO.34137, and it is deposited in the General Microbiology Center of China Culture Collection Administration of Microorganisms.

2. Use of the peanut rhizosphere non-symbiotic nitrogen-fixing bacteria as claimed in claim 1 in promoting plant growth.

3. The use according to claim 2, characterized in that The peanut rhizosphere non-symbiotic nitrogen-fixing bacteria are used to enhance the nitrogen-fixing ability of plants.

4. The use according to claim 2 or 3, characterized in that The peanut rhizosphere non-symbiotic nitrogen-fixing bacteria are used in combination with rhizobia.

5. The use according to claim 2 or 3, characterized in that The plant is a leguminous plant.

6. The use according to claim 5, characterized in that The legume plant is peanut.

7. Use of the peanut rhizosphere non-symbiotic nitrogen-fixing bacteria according to claim 1 in agricultural microbial preparations.

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