Bacillus aryabhattai and application thereof

Abstract

The invention discloses bacillus aryabhattai YL-17 and application thereof, the preservation number of the strain is CGMCC (China General Microbiological Culture Collection Center) No.33407, and the strain is preserved in the China General Microbiological Culture Collection Center (CGMCC) on January 14, 2025; the YL-17 has the capability of producing indoleacetic acid; the capacity of dissolving potassium, dissolving phosphorus and producing siderophores is achieved. The bacillus aryabhattai is prepared into a potato seed dressing agent, and pot experiments and field experiments prove that the strain YL-17 can remarkably increase the biomass of potato plants and improve the field yield of potatoes, so that the economic benefits of farmers are increased; yL-17 also has excellent salt stress resistance, and under the stress condition of salt with different concentrations, the bud length and root length of rice seeds during germination can still be obviously promoted by applying the YL-17 fungicide; the invention provides a high-quality standby strain for the microbial fertilizer industry, and shows a strong application value in the aspect of promoting crop growth.

Description

Technical Field

[0001] The invention discloses a Bacillus aryabhattai strain, relates to practical application of the strain in potato fields and its effectiveness in promoting rice seed germination and root growth under salt stress conditions, and belongs to the technical field of microorganisms. Background Art

[0002] As one of the most important food crops in the world, increasing potato production is of great significance for ensuring food security and promoting agricultural development. However, traditional agricultural farming methods often fail to achieve the desired yield increase effect when faced with environmental pressures and soil degradation. Therefore, finding efficient and environmentally friendly agricultural yield increase technologies has become an important direction of current agricultural science research.

[0003] For a long time, farmers have relied on large amounts of chemical fertilizers to increase potato yields, but this practice has led to soil hardening and acidification, destroyed the natural loose structure of the soil, and affected the normal growth of crop roots. The accumulation of nitrogen, phosphorus and other elements in chemical fertilizers will also aggravate soil acidification, which in turn has a negative impact on the growth of crops. Improper use of fertilizers will also damage soil microbial communities, reduce soil biodiversity, and affect the ecological function of the soil. In contrast, microbial fertilizers have gradually become an effective alternative to chemical fertilizers and pesticides due to their eco-friendly and soil environment-improving characteristics.

[0004] The term "rhizobacteria" was first proposed by German scientist Lorenz Hiltner in the early 20th century. Plant Growth Promoting Rhizobacteria (PGPR) refers to beneficial microorganisms that live freely in the soil or attach to the roots of plants. They can promote plant growth, improve the absorption and utilization efficiency of mineral nutrients by plants, and inhibit harmful organisms. There are many types of plant rhizosphere growth promoting bacteria, mainly including Bacillus spp., Pseudomonas spp., Enterobacter spp., Klebsiella spp., Azotobacter spp., etc. For example, some PGPR strains can colonize in plant roots or their rhizosphere soil, secrete plant hormones, dissolve insoluble elements such as phosphorus and potassium in the soil, antagonize plant pathogens or induce plant resistance. In agricultural production, PGPR bacteria have been widely used in the cultivation practices of a variety of crops. Summary of the invention

[0005] The first object of the present invention is to provide an IAA-producing Bacillus agglutinosa YL-17.

[0006] The second object of the present invention is to provide an application of Bacillus agglutinosa YL-17 for producing IAA.

[0007] The third object of the present invention is to provide a biological potato seed dressing agent to increase the field yield of potatoes, thereby achieving increased production and increased income.

[0008] A strain of Bacillus aryabhattai YL-17, with the deposit number CGMCC No.33407, was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on January 14, 2025. The depository address is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Postal Code: 100101.

[0009] The 16S rRNA nucleotide sequence of the bacterium is shown in SEQ ID NO:1.

[0010] Furthermore, the above-mentioned Bacillus arginii YL-17 has the function of producing IAA; and the Bacillus arginii has the function of resisting salt stress.

[0011] Furthermore, the above-mentioned Bacillus arginii YL-17 has the functions of solubilizing phosphate, dissolving potassium and producing iron carriers.

[0012] Furthermore, the above-mentioned Bacillus arginii YL-17, the Bacillus arginii YL-17 described in claim 1 is used as a poorly soluble calcium phosphate dissolving agent; or as an iron carrier producing agent; or as an indoleacetic acid producing agent; or as a salt stress resistance agent.

[0013] The second technical solution of the present invention is to provide a biological agent, comprising the Bacillus arnoldii YL-17 described in the first technical solution; the biological agent is used to promote the growth of potatoes; or to promote the sprout length and root length of rice seeds during germination.

[0014] Another technical solution of the present invention is to provide the use of the above-mentioned biological bacterial agent as a potato seed dressing agent.

[0015] Another technical solution of the invention is a potato seed dressing agent containing the above-mentioned biological bacterial agent.

[0016] Furthermore, the above-mentioned potato seed dressing agent also includes diatomaceous earth; the number of colonies of the biological agent is 10 8 cfu / g -1 .

[0017] Furthermore, the above-mentioned potato seed dressing agent is used to promote the growth of potatoes and increase the yield of potato tubers.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The Bacillus agglutinosa YL-17 provided by the present invention has a high IAA production capacity and has the ability to dissolve potassium, dissolve phosphorus and produce siderophores.

[0020] 2. The present invention provides a potato seed dressing made from Bacillus aeruginosa, and through pot tests and field tests, it is verified that strain YL-17 can significantly increase the biomass of potato potted plants and improve the field yield of potatoes, thereby increasing the economic benefits of farmers.

[0021] 3. The Bacillus arnoldii YL-17 provided by the present invention also has excellent salt stress resistance. Under the stress of different salt concentrations, the YL-17 bacterial agent can still significantly promote the sprout growth and root length of rice seeds during germination.

[0022] The second innovation is that under different concentrations of salt stress, the application of YL-17 bacterial agent can still significantly promote the sprout and root length of rice seeds during germination.

[0023] In addition, this patent also provides detailed methods for preparing and applying the strain, providing strong technical support for agricultural production. In summary, the innovation of this patent lies not only in the discovery of a rhizosphere growth-promoting bacterium with excellent performance, but also in its successful application in actual agricultural production, providing a new solution for increasing crop yields and income. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a staining image of YL-17 spores;

[0025] Figure 2 It is the Gram staining picture of YL-17;

[0026] Figure 3 is the phylogenetic tree diagram of YL-17;

[0027] Figure 4 This is the qualitative diagram of IAA production by YL-17;

[0028] Figure 5 This is the siderophore production map of YL-17;

[0029] Figure 6 This is the growth graph of strain YL-17 at different NaCl concentrations;

[0030] Figure 7 It is a graph of YL-17 promoting the biomass of potato potted plants;

[0031] Figure 8 This is a graph showing the growth-promoting effect of YL-17 on rice seeds under different NaCl concentration stresses. DETAILED DESCRIPTION

[0032] The following is a further detailed description of the claims of the present invention in conjunction with specific implementation methods, but does not constitute any limitation to the present invention. Any limited modifications made by anyone within the scope of the claims of the present invention are still within the protection scope of the claims of the present invention.

[0033] Unless otherwise specified, the following examples are all conventional experimental methods and operating procedures in the art.

[0034] Example 1 Screening and purification of strains

[0035] The corn rhizosphere soil of the South China Agricultural University farm was used as the screening soil sample. 10.0 g of soil sample was accurately weighed and placed in a 250 mL triangular flask (containing 5-7 glass beads) filled with 90 mL of sterile water. The sample was stirred at 180 r·min. -1 , shake on a shaker for 30 minutes to fully disperse the soil sample, let it stand for 20-30 seconds, take 5 mL of the supernatant into a test tube, and heat it in a 90℃ water bath for 10 minutes. -3 , 10 -4 , 10 -5 After concentration, 100uL was spread on LB medium (10.0g peptone, 5.0g yeast extract powder, 10.0g sodium chloride, 1L distilled water, pH 7.0-7.5).

[0036] Example 2 YL-17 Characterization

[0037] (1) Colony morphology characteristics

[0038] The colonies formed by YL-17 on LB agar medium after culturing for 24 hours were round or oval, yellow, with a moist and smooth surface, not sticky and easy to pick up.

[0039] (2) Spore staining

[0040] Pick the colonies formed after 48 hours of culture on LB agar medium and place them on a slide. Pipette 5uL of sterile water on the slide and mix with the strain, dry naturally, fix by flame heating, add 5% malachite green staining solution, heat, make it steam 3-4 times within 30 seconds, rinse with tap water for 30 seconds after cooling, add 0.5% safranin counterstaining solution, wash with water after 30 seconds, wait to dry, and observe the results under 100 times oil microscope. Results are shown in Figure 1 , the spores were green and the bacteria were red, indicating that the strain YL-17 had the ability to produce spores.

[0041] (3) Gram staining

[0042] Pick a single colony in liquid LB medium, culture it in a shaker at 37℃, 180rpm for 12h, draw 5uL of sterile water on a slide, draw 1uL of bacterial solution into the added sterile water, mix well, dry and fix on a flame; stain with crystal violet for 1min, wash with water, and dry naturally; mordant with iodine solution for 1min, wash with water, and dry; decolorize with 95% ethanol for 30s, wash with water, and dry; counterstain with 0.5% safranin for 1min, wash with water, and dry; observe under a 100x oil microscope, the bacteria are blue-purple, see Figure 2 , indicating that the strain YL-17 is a Gram-positive bacterium.

[0043] (4) Molecular biological characteristics

[0044] Pick a single colony and put it into a centrifuge tube containing 100 μL sterile water. After pipetting and beating evenly, heat it in a 95℃ water bath for 15 minutes to break the cells and release the DNA. Finally, pipette out 1 μL and add it to the PCR system (the PCR reaction system of 25 μL is: DNA template 1 μL, primer 27F (1 mM) 1 μL, primer 1492R (1 mM) 1 μL, ddH 2 O 9.5uL, 2×Taq PCRMix 12.5uL. ) for amplification and gel running verification.

[0045] PCR reaction amplification system: pre-denaturation at 95°C for 2 min, enter thermal cycle; denaturation at 95°C for 30 s, annealing at 55°C for 30 s, extension at 72°C for 1 min, a total of 32 cycles; extension at 72°C for 10 min.

[0046] 1.5% agarose gel electrophoresis was used to detect the length and concentration of the PCR product. DL2000 Maeker was selected and the gel imaging system was used to observe whether there were clear bands between the 1000bp and 2000bp bands of Maeker. The PCR amplification products with bands were sequenced by Beijing Qingke Biotechnology Co., Ltd. The obtained 16S rDNA sequences were entered into the NCBI website of the National Center for Biological Information of the United States for Blast comparison. All sequences in the database were compared and analyzed using the Blast program. Mega 7.0 software was used for sequence analysis and phylogenetic tree construction (see Figure 3 ), the YL-17 strain was determined to be Bacillus argyi, and the 16S rRNA nucleotide sequence of the strain YL-17 was shown in SEQ ID NO: 1.

[0047] (5) Physiological and biochemical characteristics: The strain YL-17 was subjected to starch hydrolysis test, gelatin liquefaction test, methyl red test, catalase test, protease test, biofilm production test, citrate utilization test and cellulose degradation test to obtain its physiological and biochemical indices. The results are shown in Table 1.

[0048] a. Starch hydrolysis test: Inoculate the YL-17 strain on the surface of the starch culture medium, repeat 3 times, and culture in a 37℃ incubator for 24 hours. After taking it out, add a small amount of Lugol's iodine solution on the surface of the culture medium, and gently rotate it to make the iodine solution evenly spread over the entire culture dish. If a colorless transparent circle appears around the colony, it means that the starch has been hydrolyzed and marked as positive, otherwise it is marked as negative.

[0049] b. Gelatin liquefaction test: Inoculate the YL-17 strain into a test tube containing gelatin culture medium, with a depth of about 2 / 3 of the gelatin layer, 3 replicates, with no culture medium as the control, and culture in a 37°C incubator for 7 days. Take out the results and observe (before observation, place the test tube in a refrigerator for 20-30 minutes to avoid liquefaction due to high temperature). If the gelatin liquefies, it means that the strain has gelatinase that can make the gelatin lose its gelling properties, marked as positive, otherwise marked as negative.

[0050] c. Methyl red test: Pick a small amount of YL-17 bacteria from the LB plate and inoculate it into the glucose peptone water culture medium, and culture it at 37℃, 180rpm for 48h. Add 2-3 drops of methyl red reagent to the culture medium, mix well and observe. If the culture medium turns red, it means that the MR test is positive, indicated by "+". If the culture medium is still yellow, the MR test is negative, indicated by "-".

[0051] d. Catalase test: Take a clean slide and drop 1 drop of 3% hydrogen peroxide solution (freshly prepared and used) on it. Pick the YL-17 strain and smear it in the hydrogen peroxide solution. If bubbles appear, it means that the strain can produce catalase and the test result is marked as positive. If bubbles are produced, it is negative.

[0052] e. Protease test: Inoculate YL-17 strains on the surface of casein culture medium, repeat 3 times, and culture in a 37℃ incubator for 24 hours. Take out and observe whether there is a transparent circle around the colony. If there is, it means that the casein has been hydrolyzed, marked as positive, otherwise marked as negative.

[0053] f. Biofilm test: Take OD 600 = 0.4, add 5 μL of bacterial solution to LBGM solid culture medium and liquid culture medium, blow dry on the clean bench for 30 min, culture in a 30°C biochemical incubator for 24 h, and observe whether wrinkles and films appear on the surface of the plate colonies and liquid culture medium.

[0054] g. Citrate test: Pick YL-17 bacteria from the agar slant and inoculate them on the citrate medium, incubate them in a 37℃ constant temperature incubator for 24-48 hours, and then observe the color change of the medium. If it turns blue, it is positive, "+", otherwise it is negative, "-".

[0055] h. Cellulose degradation test: The YL-17 strain was inoculated onto the surface of CMC culture medium with 3 replicates, cultured in a 37°C incubator for 2 days, stained with 1 / 1000 Congo red solution (1 g / L) for 30 minutes, fixed with 1 mol / L NaCl solution for 30 minutes, and finally rinsed with running water. The ability of the strain to produce cellulase was determined by the appearance of a transparent circle around the colony. If a transparent circle appeared around the colony, it indicated that the strain had the ability to produce cellulose.

[0056] Table 1 Physiological and biochemical tests of YL-17

[0057]

[0058] Note: “+” indicates positive, “-” indicates negative.

[0059] Example 3 IAA production capacity determination

[0060] (1) Qualitative determination of IAA production by YL-17

[0061] Pick a single colony from the LB plate and add it to 3 mL of 100 mg·L -1 Tryptophan LB medium, shake at 30℃, 180rpm for 24h. Pipette 200uL of bacterial solution and mix with an equal amount of Salkowski colorimetric solution (50mL 35% HClO 4 and 1mL 0.5mol·L -1 FeCl 3 Mix and prepare for use) in a white porcelain plate, and take 200uL of uninoculated bacteria containing 100mg·L -1 Tryptophan-containing LB medium and 200uL of 100mg·L -1 The IAA solution was used as the blank control and positive control and was placed in a dark environment for 30 minutes. Figure 4 As shown, the mixed solution turned red, indicating that the strain had the ability to produce IAA.

[0062] (2) Quantitative determination of IAA production by YL-17

[0063] Prepare 0, 10, 20, 30, 40, 50, 60 mg·L -1 2 mL of IAA solution of each concentration was taken and mixed with an equal amount of Salkowski colorimetric solution. After color development for 30 min in a dark environment, the OD value of the mixed solution at a wavelength of 530 nm was measured using a spectrophotometer. A standard curve was drawn with the OD value as the ordinate and the IAA solution concentration as the abscissa. The inoculated strain YL-17 was cultured overnight in LB medium and its OD was measured. 600The supernatant was mixed with an equal amount of Salkowski colorimetric solution and placed in the dark for 30 minutes. The OD value of the mixture at a wavelength of 530 nm was measured by a spectrophotometer. The OD value of the strain was calculated by comparing it with the standard curve. 600 =1.0, the amount of IAA produced is 28.52 mg·L -1 .

[0064] Example 4 Determination of other growth-promoting abilities of YL-17

[0065] (1) Determination of phosphorus solubilizing capacity

[0066] Pick a single colony and inoculate it into LB liquid medium for overnight culture (8-12h), add 1% inoculum to new LB liquid medium and shake until OD 600 =0.4, with phosphate-dissolving medium (glucose 10.0 g, (NH 4 ) 2 SO 4 0.5 g, NaCl 0.3g, KCl0.3g, FeSO 4 7H 2 O 0.03g, MnSO 4 0.03 g, Ca 3 (PO4) 2 10.0g, 1L of distilled water, pH 7.0-7.5) was added to a 1% inoculum of a triangular flask, and no bacteria were used as a blank control. After 5 days of enrichment culture, 1000uL of the culture solution was centrifuged at 10000rpm for 5 minutes, 200uL of the supernatant was added to a 50mL volumetric flask, diluted to 30mL with pure water, two drops of dinitrophenol were added, and then 5mL of molybdenum anti-color developer (100mL molybdenum anti-color developer + 1.5g ascorbic acid) was added, and the volume was adjusted to 50mL. Let it stand for 30 minutes at room temperature, and compare the color with the standard curve series working solution under the same conditions, and use a UV-visible spectrophotometer to measure the OD 700 The value was compared with the standard curve to calculate the corresponding phosphorus content.

[0067] The water-soluble phosphorus content in the bacterial culture of strain YL-17 after 5 days of culture was determined by molybdenum antimony colorimetry. The results showed that the water-soluble phosphorus content in the bacterial culture was 216.01 mg·L -1 , indicating that the strain has the ability to dissolve water-soluble phosphorus.

[0068] (2) Determination of potassium-dissolving ability

[0069] After the strain was activated and cultured overnight at 37°C and 180 rpm, it was transferred to 3 mL of LB and cultured until the OD 600 = 0.4, and inoculated into potassium-dissolving medium (glucose 5.0 g, MgSO4 7H 2 O 0.5 g, CaCO 3 0.1 g, FeCl 3 0.005 g, Ca 3 (PO4) 2 2.0g, potassium feldspar 2.0g, distilled water 1L, pH 7.0-7.2), CK treatment inoculated with an equal amount of LB, 30℃, 180rpm culture for 5d, then aspirated 5mL of bacterial solution and centrifuged at 10000rpm for 5min. The water-soluble potassium content in the supernatant of the strain was determined by flame photometry. The potassium content in CK was removed and the soluble potassium content of the strain was obtained. The experiment was repeated three times.

[0070] The soluble potassium content in the bacterial solution of strain YL-17 after 5 days of culture was determined by flame photometer. The results showed that the soluble potassium content in the bacterial solution was 2.03 mg·L -1 , indicating that the strain has the ability to convert potassium feldspar into soluble potassium.

[0071] (3) Determination of iron carrier capacity

[0072] Use a sterilized pipette tip to pick up a single colony on the purified plate and inoculate it on the iron carrier medium. Repeat three times for each plate and incubate it in a 30°C incubator for 48 hours. If a transparent halo appears, it means that the plate has iron carrier capacity. Figure 5 .

[0073] Example 5 Determination of salt stress tolerance of YL-17

[0074] LB solid culture medium containing 1%, 3%, 5%, 7%, 9%, 11% and 13% NaCl was prepared, strain YL-17 was inoculated onto the LB plate, and cultured in an incubator at 37°C for 24 h. The growth of the strain was observed and recorded, and photos were taken.

[0075] The results are as follows Figure 6 As shown, strain YL-17 can grow normally when cultured on plates containing 1%-9% NaCl, and has very good salt stress resistance, so it can be used in saline-alkali land, including extremely severe saline-alkali land.

[0076] Example 6 YL-17 growth promotion test on potato potted biomass

[0077] (1) Test materials

[0078] Potato variety tested: Favorita

[0079] Preparation of seed potato cubes: Use a sterile knife to cut the seed potatoes into cubes, each weighing between 25 and 30 grams, making sure that each piece contains 1 to 2 buds.

[0080] Preparation of potato seed dressing: streak the YL-17 strain evenly on LB solid medium plates, a total of 5 plates, and then culture them in an incubator at 37°C for 24 hours. Use a sterile cardboard to scrape the bacteria on the surface of the plate and mix it evenly with 20 grams of diatomaceous earth to prepare a plate containing 10 8 cfu / g -1 The seed dressing was prepared for use; the control group (CK) used 20 grams of diatomaceous earth without fungicide. Round flower pots with an inner diameter of 12.5 cm and a height of 11.5 cm were selected, and the amount of soil in each pot was 0.9 kg. One potato tuber was planted in each pot, and the sowing depth was about 6 cm. Four replicates were set for each treatment. On the 30th day after the potato seedlings emerged, the plant height, stem diameter, fresh weight and dry weight of the plants were measured.

[0081] After the potato plants grew for 30 days, the plant height, stem diameter, fresh weight and dry weight of the aboveground part, and fresh weight and dry weight of the underground part of the potato potted plants in the two treatment groups were measured. The measurement results are shown in Table 2.

[0082] The results showed that compared with the blank control group, the potato plants treated with YL-17 showed a significant growth-promoting effect (see Figure 7 The results showed that the application of YL-17 bacterial agent increased the plant height, aboveground fresh weight, aboveground dry weight, underground fresh weight, and underground dry weight of potatoes by 28.13%, 70.24%, 91.59%, 113.47%, and 69.23%, respectively.

[0083] Table 2 Biomass of potato potted plants for 30 days

[0084]

[0085]

[0086] Note: The values ​​in the figure are mean ± standard error. The same letters in the same column indicate that the variance is not significant (Duncan, p<0.05). The same below

[0087] Example 7 Test of YL-17 on Promoting Potato Field Yield

[0088] Preparation of potato seed dressing: streak the YL-17 strain evenly on LB solid medium plates, a total of 50 plates, and then culture them in an incubator at 37°C for 24 hours. Use a sterile cardboard to scrape the bacteria on the surface of the plate and mix it evenly with 200 grams of diatomaceous earth to prepare a plate containing 10 8 cfu / g-1 The seed potatoes were cut into blocks using sterile knives, with each block weighing between 25 and 30 grams, ensuring that each block contained 1 to 2 buds. After the seed potatoes were cut into blocks, the seed potato tubers were mixed with the microbial seed dressing prepared by strain YL-17 for use.

[0089] Test location: It was conducted in Zhu Village, Zengcheng District, Guangzhou City, Guangdong Province from January to April 2023 (113°71' east longitude, 23°98' north latitude, 3.6 meters above sea level). The test object was the Favorita potato variety. Before the start of the test, the land was plowed and ridged, and then organic fertilizer and compound fertilizer were applied in the center of the furrow. The specific amount of fertilizer applied was: 400 kg / mu of commercial organic fertilizer and 100 kg / mu of potato-specific compound fertilizer (15-8-22). A completely randomized block design (RCBD) was adopted, with a total of three repetitions. The test plot was 1.2 meters wide and 4.5 meters long, divided into three ridges, and the area of ​​each plot was 16.2 square meters. Two rows were planted per ridge, with 27 potatoes per row. The spacing between the plants was set at 20 cm and the sowing depth was 5-6 cm. The experiment included three treatment groups: Treatment 1 was a diatomaceous earth control group without added microbial agents (CK1); Treatment 2 was a commercial microbial agent control group (CK2); Treatment 3 was a diatomaceous earth control group containing 10 8 cfu·g -1 The yield of potatoes was measured 100 days after planting.

[0090] The experiment was conducted from December 2023 to March 2024 at the teaching and research base of South China Agricultural University in Zengcheng District, Guangzhou City, Guangdong Province (23°28'N 113°71'E). The test object was the Atlantic potato variety. Before the start of the experiment, the land was plowed and ridged, and then organic fertilizer and compound fertilizer were applied in the center of the furrow. The specific amount of fertilizer applied was: 400 kg / mu of commercial organic fertilizer and 100 kg / mu of potato-specific compound fertilizer (15-8-22). The experiment adopted a completely randomized block design (RCBD) with three replications. Each plot had an area of ​​18 square meters and was divided into three ridges. Each ridge was 1.0 m wide and 6.0 m long. Two rows were planted in each ridge, with 30 potatoes in each row, a plant spacing of 20 cm, and a planting depth of 5-6 cm. The experiment included three treatment groups: treatment one was a diatomaceous earth control group without bacterial agent (CK1); treatment two was a commercial bacterial agent control group (CK2); and treatment three was a diatomaceous earth control group containing 10 8 cfu·g -1 YL-17 seed dressing. After 100 days of potato planting, individual potato plants were tested and their yields were evaluated.

[0091] At the test site of Ningxi Base in Zengcheng District, Guangzhou, twelve potatoes were randomly selected for each treatment to evaluate the effect of YL-17 seed dressing agent. The test content included the weight of potato per plant, the number of commercial potatoes, and the number of fruits per plant. The test results are shown in Table 3:

[0092] Table 3 Effects of different bacterial agents on potato plants

[0093]

[0094]

[0095] Note: The values ​​in the figure are mean ± standard error. The same letters in the same column indicate that the variance is not significant (Duncan, p<0.05), the same below.

[0096] It can be seen from Table 3 that compared with the control groups CK1 and CK2, the yield per potato plant using YL-17 seed dressing agent increased by 121.62% and 82.22% respectively. Similarly, the number of commercial potato potatoes also increased by 68.35% and 27.88% respectively, and the number of potato fruits per plant also increased by 48.44% and 21.20% respectively.

[0097] The potato field test conducted at the Zhucun test site in Zengcheng District, Guangzhou City showed that compared with the control group CK1, the total yield of potatoes treated with YL-17 microbial agent increased by 32.96%, of which the yield of small potatoes increased by 29.06% and the yield of commercial potatoes increased by 33.20%. Compared with the control group CK2, the total yield of potatoes treated with YL-17 microbial agent increased by 1.66%, and the yield of commercial potatoes increased by 2.31%. If commercial potatoes are purchased at the market price of 1.6 yuan per kilogram, compared with CK1, potatoes treated with YL-17 microbial agent can bring farmers an increase of about 15,500 yuan per hectare.

[0098] Potato field trials conducted at the Ningxi test site in Zengcheng District, Guangzhou City showed that compared with the control group CK1, the total yield of potatoes treated with YL-17 microbial agent increased by 32.66%, of which the yield of commercial potatoes increased by 45.36%. Compared with the other control group CK2, the total yield of potatoes treated with YL-17 microbial agent increased by 21.06%, and the yield of commercial potatoes increased by 29.75%. If commercial potatoes are purchased at the market price of 1.6 yuan per kilogram, compared with CK1, potatoes treated with YL-17 microbial agent can bring farmers an additional income of 13,900 yuan per hectare.

[0099] Table 4 Effects of different bacterial agent treatments on potato field yield

[0100]

[0101] Note: Small potato yield refers to potatoes weighing less than 75g, and commercial potato yield refers to potatoes weighing ≥75g. The market purchase price of potatoes is 1.6 yuan / kg, and the income increase effect is compared with that of control 1.

[0102] Example 8 Experiment on the effect of YL-17 on promoting the sprout and root length of rice seeds under salt stress

[0103] (1) Preparation of bacterial suspension:

[0104] After the strains were activated, they were inoculated into LB liquid medium. After overnight culture, they were transferred to fresh LB liquid medium and shaken until OD 600 =1.0; centrifuge the bacterial solution in a centrifuge at 8000 rpm for 5 min; dilute the bacterial solution to a concentration of 10 7 cfu·mL -1 spare.

[0105] (2) The surface-sterilized Meixiangzhan No. 2 rice seeds were placed in culture dishes containing sterile wet filter paper containing 100 mM NaCl and 200 mM NaCl, respectively, with 25 seeds in each dish. Each treatment was replicated three times, divided into two treatment groups.

[0106] The first group set the salt concentration to 100mM NaCl: Treatment 1: bacterial agent treatment with 5mL YL-17 bacterial suspension; Treatment 2: no salt and no bacteria added, which is CK1; Treatment 3: 100mM NaCl was added but no bacteria was added, which is CK2.

[0107] The second group was set at a salt concentration of 200 mM NaCl: Treatment 1: 5 mL of YL-17 bacterial suspension was poured into the bacterial agent treatment; Treatment 2: No salt or bacteria was added, which was CK1; Treatment 3: 200 mM NaCl was added, but no bacteria was added, which was CK2. After 7 days of cultivation in a 25°C biochemical incubator, the sprout and root lengths of rice seeds were measured.

[0108] The test results show that YL-17 can significantly promote the sprout and root growth of rice seeds (see Figure 8 and Table 5).

[0109] Table 5 Effects of different bacterial agent treatments on rice seed germination

[0110]

[0111] Note: The values ​​in the figure are mean ± standard error. The same letters in the same column indicate that the variance is not significant (Duncan, p<0.05), the same below.

[0112] The germination rates of the first group CK1 and CK2 were 90.67% and 89.33%, respectively, and the germination rate of the inoculant treatment was 96%, which was 5.33% and 6.67% higher than that of CK1 and CK2, respectively. In terms of bud length, there were significant differences between the inoculant treatment and CK1 and CK2, and the bud length of YL-17 inoculant treatment was 14.35% and 31.62% higher than that of CK1 and CK2, respectively. In terms of root length, there were significant differences between the inoculant treatment and CK1 and CK2, and the root length of YL-17 inoculant treatment was 13.09% and 41.05% higher than that of CK1 and CK2, respectively. This shows that under the salt stress of 100mM NaC1, the inoculant treatment of YL-17 can significantly improve the germination rate of rice seeds, and promote the bud and root length of rice seeds compared with CK1 without salt and bacteria, and CK2 with 100mM NaC1 and bacteria.

[0113] The germination rate of rice seeds in the second group of different treatments was not significantly different. In terms of bud length, there was a significant difference between the inoculant treatment and CK2, and the bud length after YL-17 inoculant treatment increased by 20% compared with CK2. In terms of root length, there was a significant difference between the inoculant treatment and CK2, and the root length after YL-17 inoculant treatment increased by 27.41% compared with CK2. This shows that under the salt stress of 200mM NaCl, the inoculant treatment of YL-17 can significantly promote the bud and root length of rice compared with CK2 without adding 200mM NaCl.

Claims

1. A strain of Bacillus aryabhattai YL-17, characterized in that: The deposit number is CGMCCNo.33407, and it was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on January 14, 2025.

2. The Bacillus arifugeyi YL-17 according to claim 1, characterized in that The Bacillus arginii has the function of producing IAA; and the Bacillus arginii has the function of resisting salt stress.

3. The Bacillus arifugeyi YL-17 according to claim 1, characterized in that The Bacillus agglomerans has the functions of dissolving phosphate, potassium and producing iron carriers.

4. The Bacillus arifugeyi YL-17 according to claim 1, characterized in that The use of the Bacillus argyi YL-17 described in claim 1 as a poorly soluble calcium phosphate dissolving agent; or as a siderophore producing agent; or as an indoleacetic acid producing agent; or as a salt stress tolerance agent.

5. A biological bacterial agent, characterized in that: Contains the Bacillus argyi YL-17 described in claim 1.

6. The biological agent according to claim 1, characterized in that: The biological bacterial agent is used to promote the growth of potatoes or the growth of sprouts and roots of rice seeds during germination.

7. Use of the biological agent according to claim 5 as a potato seed dressing agent.

8. A potato seed dressing agent, characterized in that Containing the biological bacterial agent according to claim 6.

9. A potato seed dressing agent according to claim 5, characterized in that, It also includes diatomaceous earth; the number of colonies of the biological agent is 10 8 cfu / g -1 .

10. A potato seed dressing agent according to claim 9, characterized in that: Potato seed dressing is used to promote the growth of potatoes and increase potato tuber yield.

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