A strain of Ralstonia YNK-FB0054 and its application

Abstract

The present invention provides a strain of Ralstonia YNK-FB0054 and its bacterial agent and application, belonging to the field of biotechnology. Ralstonia wenshanensis The bacterial strain provided by the present invention has the functions of zinc solubilization, nitrogen fixation, organic and inorganic phosphorus solubilization, siderophore production, and indoleacetic acid production. The bacterial strain and the bacterial agent containing it as an active ingredient can promote plant seed germination and plant growth, and have high application value.

Description

Technical Field

[0001] The present invention belongs to the field of biotechnology, and in particular relates to a Ralstonia strain YNK-FB0054 and a bacterial agent and application thereof. Background Art

[0002] In recent years, long-term monoculture and the use of chemical fertilizers and pesticides have led to increasingly severe problems such as soil degradation and declining crop quality. Microbial fertilizers, due to their high efficiency and environmental friendliness, are considered one of the most promising green fertilizer alternatives to chemical fertilizers. The identification of superior bacterial strains is fundamental to the development of highly effective microbial fertilizers. Plant growth-promoting rhizobacteria (PGPR), with their remarkable growth-promoting abilities, have become a key bacterial resource for the development of microbial fertilizers.

[0003] Plant growth-promoting rhizobacteria (PGPR) are a class of beneficial microorganisms that can promote plant growth. They play an important role in promoting plant growth and development and maintaining the health of soil ecosystems through various mechanisms, such as enhancing crop nutrient absorption, inhibiting the growth of pathogens, and secreting plant hormones. However, current biotechnology-based PGPR development mainly relies on methods such as artificial mutagenesis screening and genetic engineering modification. The strains obtained in this way often face problems such as insufficient colonization ability or significantly lower field effects than laboratory levels in practical applications. To meet the needs of modern agricultural development, the development of new beneficial microbial resources with efficient and stable growth-promoting properties and easy colonization has become a key issue that needs to be urgently addressed in current agricultural production. Summary of the Invention

[0004] The invention discloses a Ralstonia strain YNK-FB0054 and an application thereof, aiming to solve the deficiencies of the prior art.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] The first aspect of the present invention provides a strain of Ralstonia ( Ralstonia wenshanensis )YNK-FB0054 was deposited in the China Center for Type Culture Collection on February 25, 2025, with the deposit number: CCTCC NO: M2025293.

[0007] The second aspect of the present invention provides the use of the above-mentioned Ralstonia sp. YNK-FB0054 in nitrogen fixation, organic phosphorus solubilization, inorganic phosphorus solubilization, siderophore production, zinc solubilization and indoleacetic acid production.

[0008] The third aspect of the present invention provides the use of the above-mentioned Ralstonia YNK-FB0054 in promoting plant growth and plant seed germination.

[0009] Through the above technical solution, the present invention can achieve at least the following beneficial effects:

[0010] 1. The Ralstonia strain YNK-FB0054 provided by the present invention has excellent nitrogen fixation and phosphate solubilization effects. It can not only solubilize inorganic phosphorus, but also organic phosphorus. In addition, the strain can also solubilize zinc, produce siderophores and indoleacetic acid, thereby effectively improving soil quality and increasing the content of nutrients that can be used by plants in the soil, thereby having a good effect of promoting plant growth.

[0011] 2. The Ralstonia sp. YNK-FB0054 provided by the present invention is a strain isolated from the soil of tobacco-wheat rotation farmland. Compared with the strains screened by laboratory mutagenesis, it has better adaptability to the planting environment and can better colonize in the soil, thereby more stably exerting its growth-promoting effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a colony morphology diagram of strain YNK-FB0054 on NA medium in Example 1;

[0013] Figure 2 This is the phylogenetic tree of strain YNK-FB0054 in Example 1 drawn using the Neighbor-Joining method;

[0014] Figure 3 The following are the results of strain YNK-FB0054 in Example 2: (A) nitrogen fixation effect diagram; (B) organic phosphorus solubilization effect diagram; (C) inorganic phosphorus solubilization effect diagram; (D) siderophore production effect diagram; (E) zinc solubilization effect diagram;

[0015] Figure 4 The figures are qualitative (A) and quantitative (B) results of the IAA production capacity of strain YNK-FB0054 in Example 2;

[0016] Figure 5 This is a graph showing the results of the germination promotion experiment of strain YNK-FB0054 in Example 3;

[0017] Figure 6 Graph showing the results of the growth promotion experiment of strain YNK-FB0054 in Example 4;

[0018] Figure 7 This is an analysis chart of agronomic trait indicators of the tomato seedling potted experiment in Example 4;

[0019] Biological Deposits

[0020] The present invention provides Ralstonia ( Ralstonia wenshanensis )YNK-FB0054, classified as Ralstonia wenshanensisYNK-FB0054 was deposited in the China Center for Type Culture Collection (CCTCC) on February 25, 2025, at Wuhan University, Wuhan, China, and its deposit number is CCTCC NO: M 2025293. DETAILED DESCRIPTION

[0021] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0022] During their research, the inventors isolated a strain of Ralstonia, YNK-FB0054, from field soil grown in a long-term flue-cured tobacco-barley rotation. Testing revealed that the strain exhibited excellent nitrogen fixation, organic and inorganic phosphorus solubilization, siderophore production, zinc solubility, and indoleacetic acid production. Further research also revealed that the strain effectively promoted seed germination, and that application of its fermentation liquid to the rhizosphere soil of plants effectively promoted plant growth, increased agricultural productivity, and promoted the sustainable development of ecological agriculture.

[0023] Based on the above findings, the present invention provides a strain of Ralstonia ( Ralstonia wenshanensis )YNK-FB0054, the deposit number of this strain is CCTCC NO: M 2025293.

[0024] The second aspect of the present invention provides the use of the Ralstonia sp. YNK-FB0054 described in the first aspect in nitrogen fixation, organic phosphorus solubilization, inorganic phosphorus solubilization, siderophore production, zinc solubilization and indoleacetic acid production.

[0025] A third aspect of the present invention provides a bacterial agent having the function of promoting plant growth, wherein the active ingredient in the bacterial agent includes the Ralstonia sp. YNK-FB0054 described in the first aspect.

[0026] According to a preferred embodiment of the present invention, the bacterial agent is a liquid bacterial agent.

[0027] Preferably, the effective viable count of Ralstonia YNK-FB0054 in the liquid bacterial agent is 1×10 6 ~1×10 11 CFU / mL. Preferably 1×10 7 -1×10 10 CFU / mL.

[0028] The fourth aspect of the present invention provides use of the Ralstonia sp. YNK-FB0054 described in the first aspect, or the biological agent described in the third aspect, in promoting plant seed germination and plant growth.

[0029] In the present invention, the method for promoting plant seed germination is as follows: soaking the plant seeds in the bacterial solution of Ralstonia sp. YNK-FB0054 described in the first aspect, and / or in the biological preparation described in the third aspect, wherein the effective viable count of Ralstonia sp. YNK-FB0054 in the bacterial solution is 1×10 6 -1×10 7 CFU / mL.

[0030] In the present invention, the method for promoting plant growth is: applying the bacterial solution of Ralstonia sp. YNK-FB0054 described in the first aspect or the biological preparation described in the third aspect to the rhizosphere soil of the plant.

[0031] According to a preferred embodiment of the present invention, the effective viable count of the bacterial solution and biological preparation is not less than 1×10 7 CFU / mL, preferably 1×10 8 -1×10 10 CFU / mL.

[0032] According to a preferred embodiment of the present invention, the amount of the bacterial solution and the biological agent is such that the effective viable count of Ralstonia YNK-FB0054 is 2×10 9 -2×10 13 CFU / strain / time, preferably 2×10 10 -2×10 12 CFU / strain / time. Preferably, the Ralstonia sp. YNK-FB0054 or the bacterial agent is applied 1-3 times per crop.

[0033] Preferably, the plant is selected from the Solanaceae family, genus Solanum, most preferably tomato.

[0034] The present invention will be described in detail below by way of examples. It should be understood that the following examples are only used to further explain and illustrate the present invention, and are not intended to limit the present invention.

[0035] In the following examples, unless otherwise specified, all reagents and materials used were purchased from regular chemical / biological reagent or material suppliers, and all reagents were of analytical grade.

[0036] In the following examples, unless otherwise specified, the operating temperature is room temperature (25±5° C.).

[0037] Example 1

[0038] This example is used to illustrate the acquisition, identification and preservation of Ralstonia sp. YNK-FB0054.

[0039] (1) Strain isolation and purification

[0040] Nutrient agar medium (NA medium) was used in the isolation and purification of the strain. The preparation method was as follows: 10 g of peptone, 3 g of beef powder, and 5 g of sodium chloride were weighed and added to 1000 mL of water. The pH was adjusted to 7.3 ± 0.1, and then 15 g of agar was added. The mixture was autoclaved at 121°C for 15 min.

[0041] A bacterial strain named YNK-FB0054 was isolated and purified from soil samples collected from a long-term flue-cured tobacco-barley rotation field by the dilution spread plate method and the streak plate method.

[0042] (2) Strain identification

[0043] 1. Identification of bacterial morphological, physiological and biochemical characteristics

[0044] Physiological and biochemical tests were performed on strain YNK-FB0054 according to the Bergey's Manual of Bacterial Identification and the Manual of Systematic Identification of Common Bacteria, and the colony morphology characteristics were described.

[0045] Colony & cell morphology: Figure 1 The colony morphology of strain YNK-FB0054 on NA medium is shown. As can be seen from the figure, the colonies of this strain are nearly round, with a smooth surface and regular edges, and are light yellow, moist, and shiny. Observation under an optical microscope shows that this strain is rod-shaped and has flagella.

[0046] Physiological and biochemical characteristics: Strain YNK-FB0054 was Gram-negative and had a pH tolerance range of 6-10. It was positive for indole production, urease, β-glucosidase, β-galactosidase, and cytochrome oxidase activities. It was also positive for nitrate reduction to nitrite, gelatin hydrolysis, and assimilation of l-arabinose, malic acid, and phenylacetic acid. The strain was able to utilize trehalose, α-d-glucose, d-fructose, d-galactose, d-fucose, l-fucose, l-aspartic acid, l-glutamic acid, Tween 40, rifamycin SV, vancomycin, tetrazolium violet, tetrazolium blue, and azithromycin.

[0047] 2. Molecular identification

[0048] The total DNA of strain YNK-FB0054 was extracted by Chelex extraction method and used as a template. 27F (5'-AGAGTTTGATCCTGGCTCAG-3') was used as the upstream primer and 1492R (5'-TACGGCTACCTTGTTACGACTT-3') was used as the downstream primer. 16S rRNA was amplified using the reaction system and conditions in Table 1.

[0049] Table 1 PCR system and conditions

[0050]

[0051] The amplified product was purified by 1% agarose gel electrophoresis (using a gel recovery and purification kit produced by Guangzhou Meiji Biotechnology Co., Ltd.) and sent to Beijing Qingke Biotechnology Co., Ltd. for sequencing. The sequencing result is shown in SEQ ID NO. 1. The sequencing results were compared and analyzed in the EZBiocloud database (https: / / www.ezbiocloud.net / ). Phylogenetic analysis was performed using 16S rRNA sequences of model strains with high homology as references. Multiple sequence alignment was performed using Clustal X 1.8 software to calculate sequence similarity between the test and reference strains. Base deletion sites were excluded during phylogenetic analysis, and a phylogenetic tree between the test and reference strains was constructed using the neighbor-joining method using MEGA 7.0. Bootstrap values ​​were set to 1000, and all other values ​​were retained at default values.

[0052] Strain YNK-FB0054 16S rRNA sequence (SEQ ID NO.1):

[0053]

[0054] Figure 2 The phylogenetic tree of strain YNK-FB0054 is shown, from which it can be seen that YNK-FB0054 and Ralstonia wenshanensis 56D2 has the highest homology, with a homology rate of 99.86%.

[0055] 3. Identification results

[0056] Combined with the molecular detection results of strain YNK-FB0054 and the bacterial morphological characteristics and physiological and biochemical characteristics, the strain was identified as Ralstonia wenshanensis .

[0057] (3) Strain preservation

[0058] The above-obtained Ralstonia wenshanensis YNK-FB0054 was deposited in the China Center for Type Culture Collection, No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, Wuhan University, on February 25, 2025, with the deposit number CCTCC NO: M2025293.

[0059] Example 2

[0060] This example is used to illustrate the Ralstonia wenshanensis )YNK-FB005 has the effects of nitrogen fixation, organic phosphorus solubilization, inorganic phosphorus solubilization, siderophore production, zinc solubilization and indoleacetic acid production.

[0061] (1) Nitrogen fixation effect test

[0062] Preparation of Asbhy nitrogen-free medium: Weigh 10 g of glucose, 0.2 g of dipotassium hydrogen phosphate, 0.2 g of sodium chloride, 0.2 g of magnesium sulfate monohydrate, 0.2 g of potassium sulfate, and 5 g of calcium carbonate, dissolve in 1000 mL of water, and add 18 ± 2 g of agar. Autoclave at 121°C for 20 min.

[0063] The strain YNK-FB0054 obtained in Example 1 was inoculated onto three Aspergillus nitrogen-free culture plates using a four-point plate inoculation method. After inoculation, the plates were placed in a 30°C incubator for 7 days. Bacterial growth and the formation of clear zones around the colonies were observed daily during the incubation period.

[0064] Figure 3(A) shows the nitrogen-fixing ability of strain YNK-FB0054. As can be seen from the figure, strain YNK-FB0054 produces a clear zone when cultured on Aspergillus nitrogen-free medium, indicating that the strain has nitrogen-fixing ability. The clear zone size was measured using the cross-hatch method, and the ratio of the clear zone diameter (D) to the colony diameter (d) was calculated to be D / d = 4.38 ± 0.64, indicating that strain YNK-FB0054 has strong nitrogen-fixing ability.

[0065] (2) Test on the effect of dissolving organic phosphorus

[0066] To prepare organophosphorus solid medium: Weigh 10 g of glucose, 0.5 g of ammonium sulfate, 0.5 g of yeast extract powder, 0.3 g of sodium chloride, 0.3 g of potassium chloride, 0.3 g of magnesium sulfate, 0.03 g of ferrous sulfate, 0.03 g of manganese sulfate, 0.2 g of lecithin, and 1 g of calcium carbonate. Dissolve in 1000 mL of water, adjust the pH to 7.3 ± 0.2, and add 18 ± 2 g of agar. Autoclave at 121°C for 20 min.

[0067] The strain YNK-FB0054 obtained in Example 1 was inoculated onto three organophosphate culture plates using the four-point plate inoculation method. After inoculation, the plates were placed in a 30°C incubator for 7 days. Bacterial growth and the formation of clear zones around the colonies were observed daily during the incubation period.

[0068] Figure 3 (B) shows the organophosphate degrading ability of strain YNK-FB0054. As can be seen from the figure, strain YNK-FB0054 produces a clearing zone when cultured on an organophosphate plate. The size of the clearing zone was measured using the cross-hatch method, and the ratio of the clearing zone diameter (D) to the colony diameter (d) was calculated to be D / d = 3.40 ± 0.35. This indicates that this strain has a good organophosphate degrading ability.

[0069] (3) Test on the effect of dissolving inorganic phosphorus

[0070] Preparation of inorganic phosphorus solid medium: Weigh 10 g of glucose, 0.5 g of ammonium sulfate, 0.3 g of sodium chloride, 0.3 g of potassium chloride, 0.3 g of magnesium sulfate heptahydrate, 0.03 g of ferrous sulfate heptahydrate, 0.03 g of manganese sulfate tetrahydrate, and 5 g of tricalcium phosphate. Dissolve in 1000 mL of water, adjust the pH to 7.3 ± 0.2, and add 18 ± 2 g of agar. Autoclave at 121°C for 20 min.

[0071] Using the four-point plate inoculation method, strain YNK-FB0054 obtained in Example 1 was inoculated onto three inorganic phosphate culture plates. After inoculation, the plates were placed in a 30°C incubator for 7 days. Bacterial growth and the formation of clear zones around the colonies were observed daily during the incubation period.

[0072] Figure 3 (C) shows the inorganic phosphate decomposition activity of strain YNK-FB0054. As can be seen from the figure, strain YNK-FB0054 produces a clearing zone when cultured on an inorganic phosphate plate, demonstrating its ability to decompose inorganic phosphate. The clearing zone size was measured using the cross-hatch method, and the ratio of the clearing zone diameter (D) to the colony diameter (d) was calculated as D / d = 2.26 ± 0.30.

[0073] (IV) Siderophore production effect test

[0074] 1. Qualitative testing

[0075] Preparation of CAS solid test medium: Weigh 60.5 mg of chrome azurol S (CAS), 72.9 mg of hexadecyltrimethylammonium bromide (HDTMA), 2.645 mg of ferric chloride hexahydrate, 295.25 mg of sodium dihydrogen phosphate dihydrate, 1213.5 mg of disodium hydrogen phosphate dodecahydrate, 125 mg of ammonium chloride, 37.5 mg of potassium dihydrogen phosphate, and 62.5 mg of sodium chloride, dissolve in 1000 mL of water, adjust the pH to 6.8 ± 0.1, and add 18 ± 2 g of agar. Autoclave at 121°C for 20 min.

[0076] Strain YNK-FB0054 obtained in Example 1 was inoculated onto CAS solid culture plates using the four-point plate inoculation method, with three replicates. After inoculation, the plates were placed in a 30°C incubator for 7 days. Bacterial growth and the development of an orange halo around the colonies were observed daily during the incubation period.

[0077] Figure 3 (D) shows the siderophore production of strain YNK-FB0054. As can be seen from the figure, strain YNK-FB0054 produces an orange halo when cultured on CAS solid culture plates, indicating that the strain is capable of producing siderophores. The size of the clear zone was measured using the cross-hatch method, and the ratio of the clear zone diameter (D) to the colony diameter (d) was calculated as D / d = 4.39 ± 0.26.

[0078] 2. Quantitative detection

[0079] Preparation of CAS color developer: add 60.5 mg of Chrome Azurol S (CAS) to 50 mL of deionized water, then add 10 mL of Fe 3+ solution (1 mM FeCl3·6H2O, 10 mM HCl) was mixed.

[0080] Strain YNK-FB0054 was inoculated into NB liquid medium and cultured at 30°C on a constant temperature shaker at 150 rpm for 48 hours. After the incubation period, approximately 2 mL of the culture medium was aspirated and filtered through a 0.22 μm sterile filter membrane. An equal volume of CAS detection solution was added. After standing for 1 hour, the OD630 of the inoculated culture medium (denoted as "As") was measured using a full-wavelength microplate reader. The OD630 of the uninoculated liquid medium was measured using the same method as the reference value (denoted as "Ar"). Siderophore concentrations were expressed as siderophore activity units (SU): SU = [(Ar - As) / Ar] × 100%. The determination was repeated three times, and the average value was used for comparison.

[0081] According to the test results, it was calculated that the iron carrier concentration produced by strain YNK-FB0054 after culturing in NB liquid medium for 48 hours was 55.51%.

[0082] (V) Zinc dissolving effect test

[0083] Preparation method of zinc-soluble solid culture medium: weigh 1 g zinc oxide, 10 g glucose, 0.2 g potassium chloride, 1 g ammonium sulfate, 0.2 g magnesium sulfate, and 0.1 g dipotassium hydrogen phosphate, add to 1000 mL water to dissolve, adjust the pH to 7.3 ± 0.1, add 20 g agar, and sterilize under high pressure at 121°C for 20 min.

[0084] The strain YNK-FB0054 obtained in Example 1 was inoculated onto zinc-soluble culture plates using the four-point plate inoculation method. Three plates were inoculated. After inoculation, the plates were placed in a 30°C incubator for 5 days. Bacterial growth and the formation of clear zones around the colonies were observed daily during the incubation period.

[0085] Figure 3 (E) shows the zinc solubility of strain YNK-FB0054. As can be seen from the figure, strain YNK-FB0054 produces a clearing zone when cultured on a zinc-solubilizing plate, demonstrating its zinc solubility. The clearing zone size was measured using the cross-hatch method, and the ratio of the clearing zone diameter (D) to the colony diameter (d) was calculated as D / d = 4.52 ± 0.38.

[0086] (VI) Test of the effect of producing indoleacetic acid

[0087] 1. Qualitative testing

[0088] KB medium: Dissolve 20 g of peptone, 15 ml of glycerol, 1.5 g of K₂HPO₄, 1.5 g of MgSO₄·7H₂O, and 0.1 g of tryptophan in 1000 mL of water and adjust the pH to 7.2 ± 0.2. Sackowcki's color developer: Slowly add 150 mL of concentrated sulfuric acid to 250 mL of deionized water while stirring. After the solution cools, add 7.5 mL of 0.5 mol / L FeCl₃·6H₂O solution.

[0089] A single colony of strain YNK-FB0054 obtained in Example 1 was inoculated into KB medium and cultured at 30°C and 180 rpm / min for 24 h. 1 mL of the fermentation broth was aseptically pipetted into a centrifuge tube and quickly mixed with 4 mL of Sackowcki's color developer. The tube was incubated in the dark at room temperature for 40 min to develop color. The color change was observed and recorded. A pink color was considered positive, indicating that the strain could secrete IAA.

[0090] Figure 4 (A) shows the color development of strain YNK-FB0054, where pink color indicates IAA production.

[0091] 2. Quantitative detection

[0092] After culturing the strain in NB medium for 1 day, a seed solution was prepared and inoculated into KB liquid medium containing L-tryptophan at a 1% inoculum. The culture was placed in a 30°C constant temperature shaker at 180 rpm. Every day, 4 ml of the supernatant was aspirated and mixed with 4 ml of Sackowcki's colorimetric reagent. After standing in the dark for 40 minutes, the OD value was measured at a wavelength of 535 nm. The obtained absorbance value was substituted into the standard curve for calculation to obtain the indoleacetic acid content of the strain, as shown in Figure 2. Figure 4 (B) The strain YNK-FB0054 produced the highest indoleacetic acid content of 35.34±0.68μg / mL on the second day.

[0093] Example 3

[0094] This example is used to illustrate the effect of Ralstonia YNK-FB0054 ( Ralstonia wenshanensis )CCTCC NO: M2025293 promotes germination of tomato seeds.

[0095] Experimental group settings: CK1: sterile water; CK2: NB blank culture medium; T1: 1.0×10 8 CFU / mL of the fermentation supernatant of the strain YNK-FB0054 obtained in Example 1 (obtained by inoculating the strain YNK-FB0054 obtained in Example 1 into NB medium for 24 h and centrifuging it at 12000 rpm for 5 min); T2: 1.0×10 7CFU / mL of the fermentation supernatant of the strain; T3: 1.0×10 6 CFU / mL of the fermentation supernatant of the strain.

[0096] Specific implementation method: Tomato seeds were used as experimental subjects. The seeds were soaked in 70% alcohol for 10 minutes and then rinsed three times with sterile water to disinfect them. The seeds that settled below the water were then soaked in water at room temperature for 12 hours. Afterwards, seeds from each group were placed in 9.00 cm transparent Petri dishes lined with 2-3 layers of sterile filter paper. Each dish contained 15 seeds per treatment, and this was repeated three times. 2 mL of liquid from each treatment group was then applied to moisten the filter paper. The seeds were then placed in a 26°C artificial climate chamber with alternating light and dark cycles of 16 and 8 hours. 2.00 mL of sterile water was then added daily to keep the filter paper moist. After 7 days, germination was recorded and root and plant lengths were measured.

[0097] Table 2 Seed germination data results

[0098]

[0099] *The data in the table with different letters indicate significant differences

[0100] Results of the germination promotion experiment: Figure 5 The germination of seeds in each experimental group on the 7th day after treatment is shown. The seeds in the control group 2 did not germinate on the 7th day after treatment with NB blank medium; the seeds in the experimental group 1 did not germinate on the 7th day after treatment with 1.0×10 8 CFU / mL of the fermentation supernatant of the strain was used to wet the filter paper for 7 days, and the seeds germinated but no cotyledons were seen. 6 CFU / mL of the fermentation supernatant of the strain was wetted with filter paper for 7 days and the seeds germinated obviously. The root length of this group was 6.36±0.16cm and the whole plant length was 9.39±0.19cm, which was significantly higher than that of the other groups. The second was experimental group 2 using 1.0×10 7 CFU / mL of the fermentation supernatant of the strain was wetted with filter paper for 7 days. The root length of this group was 4.23±0.13cm and the whole plant length was 7.18±0.18cm. The specific results are shown in Table 2. 6 -1.0×10 7 CFU / mL strain fermentation supernatant has a good effect on promoting seed germination. The experiment shows that Ralstonia YNK-FB0054 ( Ralstonia wenshanensis ) has a significant promoting effect on the germination of tomato seeds.

[0101] Example 4

[0102] This example is used to illustrate the Ralstonia YNK-FB0054 ( Ralstonia wenshanensis)CCTCC NO: M 2025293 has a growth-promoting effect on tomato plants.

[0103] Preparation of bacterial agent: The strain YNK-FB0054 obtained in Example 1 was inoculated into NB liquid culture medium and cultured at 30°C with shaking at 180 rpm for 48 h. The resulting fermentation broth was the bacterial agent of strain YNK-FB0054 (with a viable cell count of approximately 1 × 10 10 CFU / mL).

[0104] Plant planting: Add the same weight of soil to each pot, randomly group 6 pots per treatment, and plant one tomato seedling of similar growth in each pot.

[0105] Experimental group settings: CK1: sterile water; CK2: sterile NB liquid culture medium; T1: concentration of approximately 1×10 10 CFU / mL of strain YNK-FB0054; T2: concentration is about 1×10 9 CFU / mL of strain YNK-FB0054; T3: concentration is about 1×10 8 CFU / mL of strain YNK-FB0054 bacterial liquid.

[0106] Verification of growth promotion effect: Seven days after transplanting tomato seedlings into custom pots, the tomato seedlings were root-irrigated with 200 mL / plant of the above-mentioned inoculum. At the same time, tomato seedlings were treated with the same amount of sterile water and NB medium, which had been cultured under the same conditions for 48 hours with shaking, as control groups (CK1 and CK2). After root irrigation, the tomato seedlings were placed in a greenhouse to grow naturally, maintaining adequate soil moisture. Twenty-one days after root irrigation, the aboveground fresh weight, underground (root) fresh weight, stem diameter, root length, and plant height of the tomato plants were measured.

[0107] The specific measurement method is as follows:

[0108] Aboveground / belowground fresh weight: Cut the part of the tomato plant above the root base and weigh the aboveground / belowground fresh weight on an analytical balance, retaining two decimal places.

[0109] Stem Diameter: Use a vernier caliper to measure the diameter of the thickest stem part of the plant.

[0110] Root length: Straighten the roots and measure their length using a ruler.

[0111] Plant height: Straighten the plant and use a ruler to measure the length of the above-ground part from the highest point of the leaves.

[0112] pass Figure 7It can be seen that after 21 days of root irrigation with the YNK-FB0054 bacterial solution, the plant height, stem diameter, aboveground fresh weight, root length, and underground fresh weight of tomato plants were significantly increased compared to the control group (CK1) treated with pure water and the control group (CK2) treated with NB medium. The plant height of the T1 treatment group was 15.79% and 22.89% higher than that of the CK1 and CK2 controls, respectively; the root length of the T1 treatment group was 39.68% and 50.78% higher than that of the CK1 and CK2 controls, respectively; the stem diameter of the T1 treatment group was 18.76% and 45.05% higher than that of the CK1 and CK2 controls, respectively; the aboveground fresh weight of the T1 treatment group was 42.87% and 56.99% higher than that of the CK1 and CK2 controls, respectively; and the underground fresh weight of the T1 treatment group was 61.03% and 87.95% higher than that of the CK1 and CK2 controls, respectively. It can be seen that whether or not the bacterial solution is applied for treatment has a significant effect on the growth of the plants, proving that the application of strain YNK-FB0054 has a significant promoting effect on the growth of tomatoes.

[0113] Figure 6 The figure shows a comparison of tomato plants in the experimental and control groups 21 days after root irrigation. As can be seen, root irrigation with strain YNK-FB0054 resulted in faster growth than that of tomato plants treated with water or NB liquid medium alone. The roots, stems, and leaves all grew larger, and the tomato root system was more developed.

[0114] The above results show that strain YNK-FB0054 can effectively promote the growth of tomato seedlings.

[0115] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A strain of Ralstonia Ralstonia wenshanensis YNK-FB0054, characterized in that Ralstonia Ralstonia wenshanensis The deposit number of YNK-FB0054 is: CCTCC NO: M 2025293.

2. The Ralstonia sp. according to claim 1 Ralstonia wenshanensis YNK-FB0054 is used in dissolving zinc oxide, fixing nitrogen, decomposing lecithin, dissolving tricalcium phosphate, producing siderophores and producing indoleacetic acid.

3. A microbial preparation having the function of promoting plant growth, characterized in that: The active ingredient in the microbial preparation includes the Ralstonia bacteria according to claim 1 Ralstonia wenshanensis YNK-FB0054 bacterial agent.

4. The microbial preparation according to claim 3, wherein The bacterial agent is a liquid bacterial agent; in the liquid bacterial agent, the Ralstonia Ralstonia wenshanensis The content of YNK-FB0054 is not less than 1×10 6 CFU / mL.

5. The microbial preparation according to any one of claims 3 to 4 or the Ralstonia according to claim 1 Ralstonia wenshanensis Application of YNK-FB0054 in promoting tomato plant growth and tomato seed germination.

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