Methylobacterium strain YM05 and application thereof in promoting plant growth and increasing plant yield

Abstract

The invention discloses a methylobacterium YM05 strain and application thereof in promoting plant growth and increasing plant yield. The classification name of the methylobacterium YM05 is Methylobacterium sp., the preservation number of the methylobacterium YM05 is CGMCC (China General Microbiological Culture Collection Center) No.32294, and the bacterial colony of the methylobacterium YM05 is orange red, round, upwards protruded and neat in edge, and the surface of the methylobacterium YM05 is in a film shape. The methylobacterium YM05 has the capacity of efficiently synthesizing indoleacetic acid IAA, ACC deaminase and siderophore and the nitrogen fixation capacity, the bacterium and the microbial inoculum prepared from the bacterium can remarkably promote seedling growth of corn and sorghum and increase the yield, the effect is stable after multi-year multi-point application, and the methylobacterium YM05 has important significance on protection of the farming environment and green agricultural development.

Description

Technical Field

[0001] The invention belongs to the field of microbial technology and modern agricultural technology, and particularly relates to a methylbacterium strain YM05 and an application thereof in promoting plant growth and increasing plant yield. Background Art

[0002] Microbial agents are green, sustainable, and environmentally friendly live bacterial preparations, and their application in agricultural production is becoming more and more extensive. Methylobacterium has multiple functions as a biostimulant, biopesticide, and biofertilizer; it releases plant stimulants and mitogens in the rhizosphere and phyllosphere, promotes root development and nutrient absorption, enhances leaf photosynthetic efficiency, promotes flowering / fruit preservation / improves quality; improves plant immunity and releases a variety of disease resistance factors; and supplements plant root and phyllosphere nutrition by fixing nitrogen, dissolving phosphorus and potassium. Methylobacterium can be applied through seed mixing, drip irrigation, and spraying, and is suitable for vast farmland and facility agriculture; foliar spraying is suitable for special agricultural scenarios such as saline-alkali tidal flats. Methylobacterium uses methanol, a byproduct of plant growth, as a carbon raw material. It does not compete for the nutrients needed for the plant's own growth. While promoting crop growth, it can also fix carbon dioxide and methanol, helping to sequester carbon dioxide and reduce emissions. It has been reported that some Methylobacterium, such as endophytic nitrogen-fixing Methylobacterium symbioticum, Methylobacterium hispanicum, Methylobacterium oryzea, Methylobacterium radiotolerans, and Methylobacterium gregans, can promote the growth of crops such as corn, sorghum, soybeans, and peanuts, and are used in agricultural production.

[0003] Corn is not only a major food crop, but also an important feed and industrial raw material. It is an important source of food processing, light industry and medicine. my country's planting area exceeds 600 million mu, making it the largest food crop. my country is a major corn consumer and trader, with total consumption ranking second in the world. Corn imports account for more than 10% of the world's total, and its dependence on the international market is relatively high. In 2019, the yield of corn in the United States was 10532.3 kg / hectare, while my country's corn yield was only 6317.1 kg / hectare (FAO, 2020), which has great room for improvement. Sorghum is an important cash crop. In the past five years, my country's sorghum planting area has exceeded 7.5 million mu / year, and the output has reached 2.5 million tons / year. It can be used for food, sugar and medicine, with rich uses and large demand. American companies such as Newleaf and Corteva have applied for patent protection for the application of methylbacterium to promote growth and disease resistance in crops such as corn, soybeans, potatoes, and sorghum. At present, there are no methylbacterium agents and related products with completely independent intellectual property rights in China, and there is also a lack of corresponding patent protection. Therefore, it is urgent to develop Methylobacterium and its related products with completely independent intellectual property rights to effectively promote the growth of corn and sorghum, increase the yield per unit area, and provide a green and environmentally friendly approach for modern agriculture. Summary of the invention

[0004] The purpose of the present invention is to provide a methylbacterium strain YM05 and its application in promoting plant growth and increasing plant yield. The methylbacterium YM05 provided by the present invention has the ability to efficiently synthesize indoleacetic acid (IAA), ACC deaminase, and siderophore and the ability to fix nitrogen in the air, and can effectively promote the growth and increase the yield of corn and sorghum.

[0005] In order to achieve the above-mentioned invention object, the present invention adopts the following technical solutions:

[0006] The invention provides a methylobacterium YM05, whose classification name is methylobacterium Methylorubrum sp. and whose preservation number is CGMCC No. 32294.

[0007] Furthermore, the colonies of the Methylobacterium strain YM05 are orange-red, round, protruding upward, with neat edges and a film-like surface.

[0008] The invention also provides a methylobacterium bacterial agent, which contains the methylobacterium strain YM05.

[0009] The present invention also provides the use of Methylobacterium YM05 and / or Methylobacterium bacterial agent in promoting plant growth.

[0010] The present invention also provides the use of Methylobacterium YM05 and / or Methylobacterium bacterial agent in improving plant yield.

[0011] Furthermore, the plants include corn and sorghum.

[0012] Furthermore, the corn includes common corn, sweet corn, black corn, glutinous corn, and high-oil corn.

[0013] Furthermore, the sorghum includes white sorghum, red sorghum and yellow sorghum.

[0014] Furthermore, the application methods of the Methylobacterium strain YM05 include seed mixing, drip irrigation, root irrigation and foliar spraying.

[0015] Furthermore, the Methylobacterium YM05 can efficiently synthesize indoleacetic acid, ACC deaminase, siderophore and can fix nitrogen in the air.

[0016] Furthermore, the methyl bacterium agent is used to treat corn and sorghum seeds, and the bacterial content of the methyl bacterium strain YM05 is not less than 10 9 CFU / mL.

[0017] Furthermore, the bacterial content is not less than 10 9 The dosage of CFU / mL of the methyl bacterium agent is 5-25 mL per kilogram of seeds, the seed dressing temperature is 18-22° C., the seed dressing time is 5-10 minutes, and the drying time is 0.5-2 hours.

[0018] Furthermore, the methyl bacterium agent is sprayed during the seedling stage of corn and sorghum, and the bacterial content of the methyl bacterium agent is not less than 10 9 CFU / mL, the spraying amount is 10-25mL per mu.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects: the present invention screened a strain of Methylbacterium strain YM05 from corn leaves that has the ability to efficiently synthesize indoleacetic acid (IAA), ACC deaminase, iron carrier and nitrogen fixation ability. The bacteria and the bacterial agent prepared therefrom can significantly promote the growth of seedlings and increase the yield of corn and sorghum, and have high stability and good effect. For corn and sorghum planted in saline-alkali land, the yield of corn and sorghum is also significantly increased by spraying the Methylbacterium strain YM05 on the leaves. The application of the Methylbacterium strain YM05 of the present invention is of great significance to the protection of the farming environment and the development of green agriculture. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a colony morphology diagram of the Methylobacterium YM05.

[0021] Figure 2 This is a graph showing the ACC deaminase production ability test of the Methylobacterium YM05.

[0022] Figure 3 This is a graph showing the growth of the Methylobacterium YM05 on a nitrogen-free plate.

[0023] Figure 4 It is a growth curve diagram of the Methylobacterium YM05 on liquid nitrogen-free culture medium.

[0024] Figure 5 It is a comparison picture of corn seedlings in the group treated with the Methylobacterium YM05 inoculant and corn seedlings in the blank group.

[0025] Figure 6 It is a comparison picture of sorghum seedlings in the group treated with the Methylobacterium YM05 inoculant and the sorghum seedlings in the blank group.

[0026] Figure 7 It is a comparison chart of the field corn plants in the group treated with the Methylobacterium YM05 inoculant and the field corn plants in the blank group.

[0027] Figure 8 It is a comparison chart of field corn cobs in the group treated with the Methylobacterium YM05 inoculant and the blank group.

[0028] Fig. 9 This is a comparison chart of the field corn plants in the group treated with the Methylbacterium YM05 inoculant under nitrogen reduction conditions and the field corn plants in the blank group. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Example 1: Isolation and purification of strain YM05

[0031] The sample was obtained from the 11th robust leaf of corn planted in the field in Aksu City, Aksu Prefecture, Xinjiang Uygur Autonomous Region at the flaring stage. Weigh 1-2 g of the middle leaf of the 11th robust leaf and place it in a sterile shake flask, add 20-30 mL of modified R2A liquid culture medium, and place it on a shaker (30 °C, 200 rpm) for enrichment culture for 4-6 h. After enrichment, perform gradient dilution (10 -1 , 10 -2 , 10 -3 ), 50~100 µL of the dilution was spread on the modified R2A solid medium, inverted and placed in a 30°C incubator for 3-6 days, and a single pink colony was picked and placed on the modified HM solid medium with methanol as the sole carbon source and VB5 added, and continued to be cultured for 3-6 days. A single pink colony with a colony diameter of 0.9~1.2 mm was picked and purified three times to obtain the pure culture YM05 strain. The colony morphology of the YM05 strain on the modified HM solid medium is as follows Figure 1As shown, the colony is orange-red, round, protruding upward, with neat edges and a film-like surface. The 16S rRNA sequence of the YM05 strain was amplified and sequenced using primers 27F (5'-AGAGTTTGATCCTGGCTCAG-3') and 1492R (5'-GGTTACCTTGTTACG ACTT-3'), and its 16S rRNA sequence is shown in SEQ ID NO.1. Through BLAST comparison, the YM05 strain is Methylobacterium sp.

[0032] The formula of the improved R2A culture medium is: 0.2~0.3g of tryptone, 0.4~0.6g of acid-hydrolyzed casein, 0.4~0.6g of yeast extract powder, 0.4~0.6g of soluble starch, 0.2~0.4g of dipotassium hydrogen phosphate, 0.1~0.2g of magnesium sulfate, 0.2~0.4g of sodium pyruvate, 0.4~0.6g of glucose, and 10~15g of agar. Add water to 1 L, pH value 7~7.4, and sterilize at high temperature.

[0033] The formula of the improved HM medium is: 3-4 g dipotassium hydrogen phosphate trihydrate, 1-2 g sodium dihydrogen phosphate dihydrate, 0.1-0.3 gg magnesium sulfate heptahydrate, 0.4-0.6 gg ammonium sulfate, 5-15 mg disodium ethylenediaminetetraacetic acid, 0.5-2 mg ferrous sulfate heptahydrate, 1-2 mg calcium chloride dihydrate, 0.5-2 mg manganese chloride tetrahydrate, 0.1-0.3 mg sodium molybdate dihydrate, 0.2-0.4 mg copper sulfate pentahydrate, 1-2 mg cobalt chloride hexahydrate, 3-5 mg zinc sulfate heptahydrate, 20-30 g agar, add water to 1 L, sterilize at high temperature, and then add 3-10 mL methanol filtered through a 0.22 μm filter membrane.

[0034] The YM05 strain was deposited in the General Microbiology Center of China Microorganism Culture Collection (CGMCC); address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences; deposit date: October 21, 2024; the deposit number of Methylorubrum sp. YM05 is CGMCC No. 32294.

[0035] Example 2: Physiological and biochemical function test of strain YM05

[0036] In this example, the indoleacetic acid (IAA), 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, siderophore synthesis and nitrogen fixation abilities of the YM05 strain were detected.

[0037] 1. Test of IAA production capacity of Methylobacterium

[0038] The Methylobacterium strain YM05 was activated on solid modified HM medium, and a single colony was picked and placed in a test tube with 2-3 mL of liquid modified HM medium. After 2-3 days of culture, the YM05 bacterial solution that had grown to the exponential phase was transferred to a 250 mL shake flask and cultured with 40-50 mL of modified HM medium (50-100 μg / mL of L-tryptophan added). Three biological replicates were set up to control the consistency of the initial OD. After 5-7 days of culture, 1-2 mL of the bacterial solution was centrifuged at 12000 g for 5-10 min, and the supernatant was mixed with equal volumes of Salkowski's reagent (1 mL of 0.5 M FeCl3·6H2O added to 50 mL of 35% (v / v) H2SO4), and the reaction was carried out at room temperature in the dark for 20-30 min. The OD of the reaction solution was measured at 530 nm, and the IAA yield was calculated based on the standard curve. Preparation of standard curve: Prepare IAA standard solutions with concentrations of 80, 40, 20, 10, 5, 2.5, 1.25, 1, 0.5, 0.25, and 0.1 μg / mL, react with Salkowski's reagent according to the above method, and then measure the OD 530 , draw a standard curve. The reaction solution is pink, indicating that strain YM05 can produce IAA.

[0039] The formula of the improved HM medium is: 3-4 g dipotassium hydrogen phosphate trihydrate, 1-2 g sodium dihydrogen phosphate dihydrate, 0.1-0.3 gg magnesium sulfate heptahydrate, 0.4-0.6 gg ammonium sulfate, 5-15 mg disodium ethylenediaminetetraacetic acid, 0.5-2 mg ferrous sulfate heptahydrate, 1-2 mg calcium chloride dihydrate, 0.5-2 mg manganese chloride tetrahydrate, 0.1-0.3 mg sodium molybdate dihydrate, 0.2-0.4 mg copper sulfate pentahydrate, 1-2 mg cobalt chloride hexahydrate, 3-5 mg zinc sulfate heptahydrate, 20-30 g agar, add water to 1 L, sterilize at high temperature, and add 3-10 mL methanol filtered through a 0.22 μm filter membrane.

[0040] 2. Identification of the ACC deaminase production ability of Methylobacterium YM05

[0041] Pick up a single colony of activated Methylobacterium YM05 and place it on the nitrogen-deficient HM medium without ammonium sulfate. The culture dish is divided into two parts. 2-3 mM ACC is added to the right side as the only nitrogen source and evenly coated. The left side is not treated and cultured in a 30 ℃ incubator for 3-6 days. A single colony is found on the right side. Figure 2 As shown, it indicates that strain YM05 can utilize ACC as a nitrogen source, that is, it can produce ACC deaminase.

[0042] The formula of nitrogen-deficient alternative HM medium is: 3-4 g dipotassium hydrogen phosphate trihydrate, 1-2 g sodium dihydrogen phosphate dihydrate, 0.1-0.3 g magnesium sulfate heptahydrate, 5-15 mg disodium ethylenediaminetetraacetic acid, 0.5-2 mg ferrous sulfate heptahydrate, 1-2 mg calcium chloride dihydrate, 0.5-2 mg manganese chloride tetrahydrate, 0.1-0.3 mg sodium molybdate dihydrate, 0.2-0.4 mg copper sulfate pentahydrate, 1-2 mg cobalt chloride hexahydrate, 3-5 mg zinc sulfate heptahydrate, 20-30 g agar, add water to 1 L, sterilize at high temperature, and then add 3-10 mL of methanol filtered through a 0.22 μm filter membrane.

[0043] 3. Test of the iron carrier production ability of Methylobacterium YM05

[0044] Pick a single colony of Methylobacterium YM05 into a modified HM liquid medium, culture at 200 rpm and 30 ℃ for 2-3 days, transfer the YM05 test tube bacterial solution that has grown to the exponential phase to a 250 mL shake flask, culture it with modified HM medium, set up 3 biological replicates, and control the initial OD to be consistent. After 3-5 days of culture, take 0.5-1 mL of bacterial solution and centrifuge it at 10000 g for 5-10 min, mix the supernatant with an equal volume of CAS detection agent, react at room temperature in the dark for 25-30 min, and measure the OD of the reaction solution at 630 nm as (As), take another equal volume of blank culture medium and CAS detection solution and mix them, and use its absorbance value as the reference value (Ar), and calculate according to the root formula [(Ar-As) / Ar]×100%, and the relative content of the iron carrier is obtained. The reaction solution is blue-gray, indicating that strain YM05 can produce iron carriers.

[0045] CAS detection agent preparation method: Reagent 1, 50~60 mg chrome azuro is dissolved in 50 mL ultrapure water; Reagent 2, FeCl3·6H2O is dissolved in 10 mM hydrochloric acid to prepare a 1~2 mM FeCl3·6H2O solution; Reagent 3, 60~75 mg HDTMA is dissolved in 40 mL ultrapure water. After mixing reagents 1 and 2, slowly pour reagent 3 while stirring to obtain CAS detection solution (20×), which is diluted when used.

[0046] 4. Test of nitrogen fixation ability of Methylobacterium

[0047] A single colony of the Methylobacterium strain YM05 was selected and inoculated into a modified DMSZ Medium No.3 nitrogen-free medium and cultured at 30°C for 5-8 days. Colonies were found to grow. Figure 3 As shown, the colonies are pink, round, protruding upward, with neat edges and a film-like surface, indicating that strain YM05 has the ability to fix nitrogen.

[0048] A single colony of the Methylobacterium strain YM05 was picked up and placed in a modified HM liquid medium, cultured at 200 rpm and 30 °C for 2-3 days, and the YM05 test tube culture solution that had grown to the exponential phase was transferred to a 500 mL shake flask and cultured in a modified DMSZ Medium No.3 nitrogen-free medium. Three biological replicates were set to control the consistency of the initial OD. The OD of the reaction solution was measured at 630 nm, and a growth curve was drawn. It was found that the strain YM05 could also grow in the liquid medium, such as Figure 4 As shown, it indicates that strain YM05 has the ability to fix nitrogen.

[0049] Pick the single colony of the methylbacterium YM05 into the modified HM liquid medium, culture at 200 rpm and 30 °C for 2-3 days, connect the YM05 test tube bacterial solution that has grown to the exponential phase to a 500 mL shake flask, culture for 3-5 days until the mid- and late exponential phase, collect the bacterial solution and centrifuge at 10000 g for 5-10 min, resuspend the bacterial precipitate with 10-20 mL of modified DMSZ Medium No.3 nitrogen-free medium, transfer it to a 300 mL drip bottle, fill it with 5-10% acetylene gas with a syringe, mix it after injection, place it in a 30 °C 220 rpm shaker for culture, extract the gas in 0.1-0.25 mL of the bottle after culturing for 2-4 hours, and use gas chromatography GC to detect the generation of acetylene in the gas in the bottle. It was found that the gas in the bottle GC detected the ethylene peak, indicating that the strain YM05 can reduce acetylene to ethylene and has nitrogenase activity.

[0050] The formula of DMSZ Medium No.3 culture medium is: 3~7 g glucose, 3~7 g mannitol, 0.1~0.2 g calcium chloride dihydrate, 0.1~0.2 g magnesium sulfate heptahydrate, 3~7 mg sodium molybdate dihydrate, 0.7~1.2 g dipotassium hydrogen phosphate, 0.1~0.2 g potassium dihydrogen phosphate, 0.01~0.02 g ferrous sulfate heptahydrate, 3~7 g calcium carbonate, 15~20 g agar, and 1 L of water; at the same time, 1 mL of trace element solution is added to every 40 mL of culture medium, and the trace element solution composition is 7~12 mg zinc sulfate heptahydrate, 2~5 mg manganese chloride tetrahydrate, 20~40 mg boric acid, 15~30 mg cobalt chloride hexahydrate, 0.5~1.5 mg cupric chloride dihydrate, and 1~3 mg nickel chloride hexahydrate.

[0051] As shown in Table 1 , strain YM05 has the ability to synthesize indoleacetic acid (IAA), 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, siderophore, and nitrogen fixation.

[0052] Table 1: Identification of physiological and biochemical properties of Methylobacterium YM05

[0053]

[0054] Example 3: Methylobacterium YM05 promotes the growth of corn and sorghum seedlings

[0055] Pick the YM05 single colony into a test tube containing 2-3 mL of liquid HM medium, culture at 30°C, 200 rpm for 2-3 days, take 0.5-1 mL of bacterial solution and transfer to 40-50 mL of liquid HM medium, culture at 30°C, 200 rpm for 3-4 days until OD 600 5-10 mL of bacterial solution was centrifuged at 6000 rpm for 5-10 min, the supernatant was discarded, 5-10 mL of 10 mM MgSO4 solution was added, the mixture was mixed in a vortex, and the mixture was centrifuged again at 6000 rpm for 5-10 min. The supernatant was discarded, 5-10 mL of 10 mM MgSO4 solution was added, and the mixture was mixed in a vortex to obtain the Methylobacterium YM05 bacterial agent (about 10 9 CFU / mL). Different application methods of Methylobacterium YM05 significantly promoted the growth of corn and sorghum seedlings.

[0056] Seed dressing: 100-200 corn seeds and sorghum seeds were respectively mixed with 5-10 mL of diluted Methylobacterium YM05, with 10 mL of Methylobacterium YM05 per seed. 5 ~10 6 CFU, and then sowed into the seedling tray filled with seedling medium. Each group was sown with 32 seedling holes. The seedlings continued to grow until the 30th to 35th day, and the plant height, fresh weight, plant dry weight, and root dry weight of the whole seedlings were measured. The various indicators are shown in Table 2. On the 35th day, the seedlings were Figure 5 and Figure 6 shown.

[0057] Foliar spraying: Sow corn seeds and sorghum seeds in seedling trays filled with seedling substrate, with 32 seedling holes in each group. On the 7th to 10th day after sowing, spray the bacterial solution on the leaves of corn and sorghum seedlings at a spraying rate of 10 5 ~10 6 CFU / plant. The seedlings continued to grow until the 30th to 35th day, and the plant height, fresh weight, plant dry weight and root dry weight of the whole seedlings were measured. The indicators are shown in Table 2.

[0058] Seed dressing + foliar spraying: 100-200 corn seeds and sorghum seeds were mixed with 5-10 mL of diluted Methylobacterium YM05, with 10 mL of Methylobacterium YM05 per seed. 5 ~10 6CFU, mix thoroughly and sow into the seedling tray filled with seedling medium, 32 seedling holes for each group, and spray the bacterial solution on the leaves of corn and sorghum seedlings on the 7th to 10th day after sowing, with a spraying rate of 10 5 ~10 6 CFU / plant. The seedlings continued to grow until the 30th to 35th day, and the plant height, fresh weight, plant dry weight and root dry weight of the whole seedlings were measured. The indicators are shown in Table 2.

[0059] Root irrigation: Sow corn seeds and sorghum seeds in seedling trays filled with seedling substrate, with 32 seedling holes in each group. 7-10 days after sowing, irrigate the roots of corn and sorghum seedlings with an application rate of 10 5 ~10 6 CFU / plant. The seedlings continued to grow until the 30th to 35th day, and the plant height, fresh weight, plant dry weight and root dry weight of the whole seedlings were measured. The indicators are shown in Table 2.

[0060] As shown in Table 2, different application methods of inoculation with YM05 can significantly improve the growth of corn and sorghum seedlings. The plant height, fresh weight, plant dry weight and root dry weight of corn seedlings inoculated with YM05 were increased by 10-20%, 20-40%, 20-30% and 10-20% respectively compared with the blank group; the height, fresh weight, root dry weight and plant dry weight of sorghum seedlings inoculated with YM05 were increased by 15-25%, 15-35%, 20-35% and 10-25% respectively compared with the blank group.

[0061] Table 2: Effects of different application methods of Methylbacterium YM05 on the growth promotion of corn and sorghum seedlings

[0062]

[0063] Example 4: Methylobacterium YM05 bacterial agent promotes the growth of corn and sorghum plants in the field

[0064] Each experimental group in the field experiment was 6×20 m 2 The seeding was done by machine, with a row spacing of 70 cm and a plant spacing of 25 cm, with 8 rows in each group. The experimental groups were sprayed with Methylobacterium YM05 at 20-30 days and 50-60 days after sowing in the field, with a spraying concentration of 10 5 ~ 10 6 CFU / plant, spraying volume was 2~3 L / group, the control group was sprayed with 10 mM magnesium sulfate solution, spraying volume was 2~3 L / group; sampling was carried out at 5 points during the grain filling period, 10 healthy plants were continuously sampled at each point, and a total of 50 plants were taken to count the plant growth of field corn and sorghum. The results are shown in Table 3 and Figure 7As shown in the figure, the treatment with Methylobacterium YM05 increased the height of corn plants by 10-15% and the length of leaves at the ear by 12-15%, while the treatment with Methylobacterium YM05 increased the height of sorghum plants by 15-20%. Methylobacterium YM05 had no significant effect on the stem diameter of corn and sorghum plants.

[0065] Table 3: Methylobacterium YM05 inoculant promotes the growth of corn and sorghum plants

[0066]

[0067] Example 5: Methylobacterium YM05 inoculant increases field corn and sorghum yields

[0068] The method described in Example 4 was used to plant corn and sorghum in different areas, and the effect of YM05 bacterial agent on corn and sorghum yield was detected. Corn was planted in multiple locations for many years (2023 Pingdu summer corn, 2024 Jimo spring corn, 2024 Pingdu summer corn). Corn and sorghum were harvested after maturity, and ear length, thousand-grain weight and yield per mu were calculated. The results are shown in Table 4 and Figure 8 As shown in the results, the treatment of Methylobacterium YM05 increased the length of corn ear by 5-10%, the thousand-grain weight by 8-12%, and the yield per mu by 14-18% compared with the control group, and the effect of multi-year multi-point testing was stable; in Dongying saline-alkali land, the application of Methylobacterium YM05 increased the length of corn ear by 5-8%, the thousand-grain weight by 8-10%, and the yield per mu by 8-10%. The treatment of Methylobacterium YM05 increased the length of sorghum ear by 12-16%, the thousand-grain weight by 10-15%, and the yield per mu by 15-20% compared with the control group; in Dongying saline-alkali land, the application of Methylobacterium YM05 increased the length of sorghum ear by 9-11%, the thousand-grain weight by 8-10%, and the yield per mu by 7-10%.

[0069] Table 4: Methylobacterium YM05 inoculant improves corn and sorghum yields

[0070]

[0071] Example 6: Methylobacterium YM05 bacterial agent increases corn and sorghum yields in saline-alkali land fields

[0072] The method described in Example 4 was used to plant corn and sorghum in saline-alkali land in Guangrao County, Dongying, and the effect of YM05 on the yield of corn and sorghum planted in saline-alkali land was detected. The results are shown in Table 4. When corn was planted in saline-alkali land, the application of Methylbacterium YM05 increased the corn ear length by 5-8% compared with the control group, the thousand-grain weight by 8-10%, and the per-acre yield by 8-10%. When sorghum was planted in saline-alkali land, the application of Methylbacterium YM05 increased the sorghum ear length by 9-11% compared with the control group, the thousand-grain weight by 8-10%, and the per-acre yield by 7-10%.

[0073] Example 7

[0074] Corn was planted in a 16 cm × 45 cm square pot with 8-10 kg of field soil. Based on the nitrogen, phosphorus and potassium requirement ratio (1:0.48:0.8) of the entire corn growth cycle, different nitrogen-reducing base fertilizers (N-0, N-10, N-25, N-50) were prepared. The nitrogen fertilizer was applied twice, half as base fertilizer at sowing time and half as topdressing at the corn trumpet stage. The experimental group was treated with Methylobacterium YM05 for 5-10 min (10 5 ~10 6 CFU / grain), plant after drying, manage normally after sowing, water every 3-5 days, 1L is appropriate, apply topdressing around the small trumpet stage of corn, add the other half of nitrogen fertilizer, and spray the strain on the leaves of the experimental group again (10 5 ~10 6 CFU / plant). Samples were taken and evaluated about 50 to 60 days after corn seedlings emerged. Fig. 9 As shown, when nitrogen was reduced by 10-25%, the fresh weight of corn plants still increased by 5-8% compared with the control group, the dry weight of plants increased by 4-6%, the nitrogen content of plant leaves increased by 6-9%, and the chlorophyll content of plant leaves increased by 4-7%.

[0075] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to replace some of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions claimed to be protected by the present invention.

Claims

1. A strain of Methylobacterium YM05, characterized in that The classification name of the methyl bacterium YM05 is methyl bacterium Methylorubrum sp., the deposit number is CGMCC No. 32294.

2. Methylobacterium YM05 according to claim 1, characterized in that The Methylobacterium YM05 colony is orange-red, round, protruding upward, with neat edges and a film-like surface.

3. A methylbacterium bacterial agent, characterized in that The methylbacterium bacterial agent contains the methylbacterium YM05 described in claim 1.

4. Use of the Methylobacterium YM05 according to claim 1 and / or the Methylobacterium agent according to claim 3 in promoting plant growth.

5. Use of the Methylobacterium YM05 according to claim 1 or the Methylobacterium agent according to claim 3 in increasing plant yield.

6. The use according to claim 4 or 5, characterized in that: Such plants include corn and sorghum.

7. The use according to claim 4 or 5, characterized in that: The application methods of the methylbacterium YM05 and the methylbacterium agent include seed dressing, drip irrigation, root irrigation and foliar spraying.

8. The use according to claim 7, characterized in that: The methyl bacterium YM05 can efficiently synthesize indoleacetic acid, ACC deaminase, iron carrier and can fix nitrogen in the air.

9. The use according to claim 7, characterized in that: When the methylbacterium strain YM05 is used to treat corn and sorghum seeds, the bacterial content is not less than 10 9 CFU / mL; bacterial content is not less than 10 9 The dosage of CFU / mL of the methyl bacterium agent is 5 to 25 mL per kilogram of seeds, the seed dressing temperature is 18 to 22° C., the seed dressing time is 5 to 10 minutes, and the drying time is 0.5 to 2 hours.

10. The use according to claim 7, characterized in that: The methyl bacterium agent is sprayed on the seedling stage of corn and sorghum, and the bacterial content of the methyl bacterium agent is not less than 10 9 CFU / mL, the spraying amount is 10-25mL per mu.

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