Application of Microbacterium alginolyticum H117 with phosphorus dissolution, potassium release and nitrogen fixation functions in promoting growth and disease resistance

Abstract

The application discloses application of a microbacterium azooicum H117 with functions of dissolving phosphorus, decomposing potassium and fixing nitrogen in promoting growth and resisting diseases. Microbacterium algihabitans The strain H117 is identified as H117, and the strain has been preserved in a Guangdong Microbial Culture Collection Center (GDMCC) with a preservation number of GDMCC No: 68734. The microbacterium azooicum H117 disclosed by the application has functions of producing an iron carrier, decomposing potassium, fixing nitrogen, degrading cellulose, mineralizing insoluble organic phosphorus and dissolving insoluble inorganic phosphorus, and can inhibit growth of a Colletotrichum gloeosporioides (up to 35.3% of bacteriostatic efficiency) and significantly promote growth of tomatoes. Therefore, the microbacterium azooicum H117 disclosed by the application has important research value and application potential in disease prevention and growth promotion.

Description

Technical Field

[0001] This invention relates to the field of agricultural microbial technology, and in particular to the application of a strain of Algal Microbacterium H117 with phosphorus-solubilizing, potassium-solubilizing, and nitrogen-fixing functions in promoting growth and disease resistance. Background Technology

[0002] Modern agriculture heavily relies on chemical fertilizers and pesticides to ensure crop yields, but long-term excessive application has led to a series of ecological and safety problems, including soil compaction, nutrient imbalance, eutrophication of water bodies, and increased pesticide resistance in pathogens. Developing microbial fertilizers and preparations using plant rhizosphere growth-promoting bacteria (PGPR) has become an important approach to achieving green and sustainable agricultural development due to its multiple functions, including nutrient activation, secretion of growth-promoting substances, and antagonism of pathogens. Among these, strains possessing multiple growth-promoting mechanisms such as phosphorus solubilization, potassium solubilization, nitrogen fixation, and iron production, while also inhibiting soil-borne diseases, have higher development value and broader application prospects because they can significantly improve the nutritional status and microecological environment of plant rhizospheres through synergistic effects.

[0003] Most phosphorus and potassium in soil exist as insoluble minerals or organic complexes, which cannot be directly absorbed and utilized by plants. Phosphate-solubilizing bacteria can mineralize insoluble inorganic and organic phosphorus into available phosphorus by secreting organic acids and phosphatases; potassium-solubilizing bacteria can release potassium from mineral lattices through acid hydrolysis and complexation. Nitrogen-fixing bacteria can convert atmospheric molecular nitrogen into ammonium nitrogen, directly providing nitrogen sources for plants. Iron-carrying microorganisms secrete high-affinity iron chelates, which not only help plants obtain iron nutrition in iron-deficient environments but also inhibit the growth and reproduction of various pathogens by competing for limited iron ions in the rhizosphere, thus possessing both growth-promoting and disease-preventing functions. If these functions are integrated into a single strain, it is expected that the input of chemical fertilizers and pesticides can be reduced while achieving an organic combination of nutrient activation, plant growth promotion, and biological disease control, which has significant application value.

[0004] Tomatoes are an important vegetable crop widely cultivated worldwide, produced by *Colletotrichum candida* (…). Colletotrichum gloeosporioides Anthracnose and other fungal diseases caused by bacteria pose a serious threat to the yield and quality of tomatoes. Traditional chemical control faces bottlenecks such as excessive residues and the development of resistance. Screening for multifunctional biocontrol and growth-promoting strains that can effectively antagonize the main pathogenic fungi of tomatoes and directly promote tomato growth through multiple biochemical mechanisms is currently a hot topic and a challenge in the research and development of microbial agents. At present, some Bacillus and Pseudomonas species have been reported to have partial functions such as phosphorus solubilization, potassium solubilization, or nitrogen fixation. However, multifunctional strains that simultaneously possess highly efficient phosphorus solubilization (including mineralization of insoluble organic and inorganic phosphorus), potassium solubilization, nitrogen fixation, iron carrier production, and can effectively antagonize Colletotrichum anthracnose while significantly promoting tomato growth are still very scarce.

[0005] Algal microbacteria ( Microbacterium algihabitansBelonging to the genus *Microbacterium*, early isolates were mostly found in special habitats such as oceans and sediments, and research on its functional characteristics in agriculture, such as growth promotion and disease resistance, is extremely scarce. To date, there are no publicly available reports of *Microbacterium algae* simultaneously possessing multiple functional activities, including efficient phosphorus solubilization, potassium solubilization, nitrogen fixation, iron production, antagonism against *Colletotrichum gloeosporioides*, and promotion of tomato growth. Therefore, discovering and utilizing a novel *Microbacterium algae* strain with these combined functions is of significant practical importance for enriching multifunctional microbial resources, developing efficient microbial fertilizers and biocontrol agents, and promoting green and efficient production of crops such as tomatoes. Summary of the Invention

[0006] The purpose of this invention is to provide a strain of algae-forming microbacterium with phosphorus-solubilizing, potassium-solubilizing, and nitrogen-fixing functions. Microbacterium algihabitans The application of H117 in promoting growth and resisting disease provides a new microbial resource for promoting tomato growth and preventing anthracnose caused by Colletotrichum gloeosporioides.

[0007] The first objective of this invention is to provide a strain of *Microbacterium urinaria* isolated from the leaves of Wogan mandarin oranges. Microbacterium algihabitans H117, this strain was deposited on July 27, 2026 at the Guangdong Provincial Microbial Culture Collection Center (GDMCC), located at 5th Floor, Building 59, No. 100 Xianlie Middle Road, Yuexiu District, Guangzhou, Guangdong Province, 510070, China, with accession number GDMCCNo: 68734.

[0008] Identification characteristics of strain H117: Strain H117 is a Gram-positive bacterium. On R2A medium, single colonies are nearly round, yellow, glossy, and have regular edges. The 16S rRNA gene sequence of strain H117 is 1522 bp in length. Sequence alignment analysis shows that this strain is related to... Microbacterium algihabitans T (GCA_032464975.1) showed the highest similarity, at 100%. Based on comparative genomic analysis, strain H117 was most similar to the model strain of *Microbacterium tumefaciens*. Microbacterium algihabitans T The average nucleotide identity (ANI) of (GCA_032464975.1) was 98.66%, and the digital DNA-DNA hybridization value was 88.7%. When the ANI values ​​of two bacterial genomes are less than 95%, they are considered different species. A genome-wide DNA-DNA hybridization value of 70% is the gold standard for prokaryotic species classification. Furthermore, phylogenetic tree construction using UBCG v3.0 to compare the strain with the reference model strain showed that strain H117 is related to *Microbacterium tumefaciens*. Microbacterium algihabitans T They are the same species.

[0009] This invention discovered that strain H117 possesses siderophore capabilities; strain H117 can mineralize insoluble organic and inorganic phosphorus; strain H117 exhibits potassium solubilization and nitrogen fixation functions; strain H117 can inhibit *Colletotrichum gloeosporioides* (…). Colletotrichum gloeosporioides Inoculation of tomato plants with strain H117 significantly promotes tomato growth.

[0010] A second objective of this invention is to provide a microbial preparation containing the cells and / or cultures of the aforementioned *Microbacterium tumefaciens* H117.

[0011] Preferably, the microbial preparation is a microbial fertilizer.

[0012] Preferably, the culture includes fermentation broth, supernatant of fermentation broth, etc.

[0013] A third objective of this invention is to provide the application of the aforementioned *Microbacterium tumefaciens* H117 or the aforementioned microbial preparation in siderogenic carriers.

[0014] A fourth objective of this invention is to provide the application of the above-mentioned *Microbacterium tumefaciens* H117 or the above-mentioned microbial preparation in the mineralization of insoluble organic phosphorus and / or the dissolution of insoluble inorganic phosphorus.

[0015] The fifth objective of this invention is to provide the application of the above-mentioned Algal Microbacterium H117 or the above-mentioned microbial preparation in nitrogen fixation.

[0016] The sixth objective of this invention is to provide the application of the above-mentioned *Microbacterium tumefaciens* H117 or the above-mentioned microbial preparation in potassium solubilization.

[0017] The seventh objective of this invention is to provide the application of the above-mentioned *Microbacterium tumefaciens* H117 or the above-mentioned microbial preparation in the production of cellulase.

[0018] The eighth objective of this invention is to provide the application of the above-mentioned *Microbacterium tumefaciens* H117 or the above-mentioned microbial preparation in inhibiting the growth of *Colletotrichum gloeosporioides*.

[0019] The ninth objective of this invention is to provide the application of the above-mentioned *Microbacterium tumefaciens* H117 or the above-mentioned microbial preparation in promoting plant growth.

[0020] Preferably, the plant is a tomato.

[0021] The present invention has the following advantages over the prior art: 1) Microbacterium tumefaciens H117 is related to... Microbacterium algihabitans T (GCA_032464975.1) Same species.

[0022] 2) The algae-bacterium H117 can not only produce iron carriers, but also mineralize insoluble organic phosphorus and dissolve insoluble inorganic phosphorus, and has the ability to solubilize potassium and fix nitrogen.

[0023] 3) Microbacterium tumefaciens H117 can inhibit the growth of Colletotrichum anthracis.

[0024] 4) Microbacterium tumefaciens H117 can significantly promote the growth of tomatoes.

[0025] Therefore, the *Microbacterium algae* H117 disclosed in this invention can improve the crop's resistance to *Colletotrichum gloeosporioides* infection and promote tomato growth, and has broad application prospects in the preparation of crop microbial fertilizers and microbial preparations.

[0026] Microbacterium algihabitans H117, this strain was deposited on July 27, 2026 at the Guangdong Provincial Microbial Culture Collection Center (GDMCC), located at 5th Floor, Building 59, No. 100 Xianlie Middle Road, Yuexiu District, Guangzhou, Guangdong Province, 510070, China, with accession number GDMCC No: 68734. Attached Figure Description

[0027] Figure 1 This is a colony morphology diagram of strain H117 in Example 1 on R2A medium.

[0028] Figure 2 This is a genomic phylogenetic tree diagram of strain H117 in Example 3.

[0029] Figure 3 This is a result diagram of the siderophore produced by Microbacterium tumefaciens H117 in Example 4.

[0030] Figure 4 The graph shows the results of the phosphorus-solubilizing ability of Microbacterium tumefaciens H117 in Example 5. In the graph, A: the result of the strain being inoculated on a poorly soluble organic phosphorus medium; B: the result of the strain being inoculated on an inorganic phosphorus medium.

[0031] Figure 5 This is a plate graph showing the potassium-solubilizing ability of Microbacterium tumefaciens H117 in Example 6.

[0032] Figure 6 This is a plate graph showing the nitrogen-fixing function of *Microbacterium tumefaciens* H117 in Example 7.

[0033] Figure 7 This is a plate diagram of cellulose degradation by Microbacterium urinaria H117 in Example 8.

[0034] Figure 8 This is a graph showing the results of the antibacterial effect of Microbacterium tumefaciens H117 inoculated in Example 9 against Colloidal anthrax.

[0035] Figure 9This is a graph showing the results of the growth-promoting effect of inoculating *Microbacterium tumefaciens* H117 on tomatoes in Example 10. Detailed Implementation

[0036] The following are specific implementation examples of the present invention. It should be noted that these embodiments are merely examples and do not constitute any limitation on the scope of the present invention. Modifications and substitutions to the details and form of the implementation schemes within the scope and spirit of the present invention all fall within the protection scope of the present invention. Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the experimental reagents used in the following embodiments are all conventional biochemical reagents.

[0037] Example 1: Isolation of strain H117 This strain was isolated from leaves of Wogan oranges in a Wuming Wogan orange orchard in Guangxi. Endophytic bacteria were isolated from the leaves using high-throughput isolation, culture, and identification techniques. The specific procedures were as follows: 10g of fresh leaves were taken, ground, and then diluted 5000-fold with sterile magnesium chloride solution and 10% TSB liquid medium, followed by a further 2000-fold dilution. 160μL of the diluted solution was added to 48 wells of a 96-well cell culture plate and incubated at 30℃ in the dark for 2 weeks. 10μL of the bacterial culture was evenly aspirated from each well of the culture plate, and bacterial DNA was extracted using an alkaline lysis method. 140μL of 80% (v / v) glycerol was added to the remaining bacterial culture and stored as a bacterial glycerol stock for subsequent bacterial activation. PCR amplification was performed using primers 799F / 1193R (V5-V7 region of the 16S rRNA gene) and Novizan's Green TaqMix. The product was diluted 120-fold and used as a template for PCR amplification using primers 799F and 1193R with sequencing adapters (Illumina adapter) and barcodes. The second round of PCR products were electrophoresed, and approximately 550 bp bands were excised for purification and concentration determination. Each 96-well plate contained 100 ng of the mixed library, totaling 4800 ng for 48 plates. High-throughput sequencing was performed at Novogene Corporation of Beijing. The sequencing data were analyzed using the Culturome analysis suite (https: / / github.com / YongxinLiu / Culturome) to determine the location of the cultured bacteria in the 96-well plates. 25 μL of bacterial culture was aspirated from the corresponding well of the 96-well cell culture plate and activated on 1 / 2 TSA medium. The bacteria were purified using a streak plating method to obtain purified strain H117. The purified bacterial strain was mixed with 25% glycerol (v / v) and stored at -20°C.

[0038] Morphological identification revealed that strain H117 is a Gram-positive bacterium. On R2A medium, single colonies are approximately round, yellow, glossy, and have regular edges.Figure 1 ).

[0039] Example 2: 16S rRNA gene sequence analysis of strain H117

[0040] Genomic DNA was extracted from strain H117 using an alkaline lysis method, and the full-length 16S rRNA gene was amplified using the universal bacterial primers 27F / 1492R. The PCR product was sent to Suzhou Genewiz Biotechnology Co., Ltd. for sequencing, and the sequence is shown in SEQ ID NO. 1, with a length of 1522 bp. The sequenced data was compared with the EzBioCloud website (https: / / www.ezbiocloud.net / identify). The results showed that strain H117 is compatible with the model bacterial species. Microbacterium algihabitans T KSW2-21 (GCA_032464975.1) has the highest similarity, at 100%.

[0041] Full-length 16S rRNA gene sequence of strain H117 (SEQ ID NO.1):

[0042] Example 3: Whole genome sequence analysis of strain H117 Strain H117 was sent to Shanghai Meiji Biotechnology Co., Ltd., where its genome was sequenced using the Illumina Novaseq platform. The bacterial genome sequence was assembled using SPAdes v3.15.3 software, removing low-quality contig sequences shorter than 500 bp. The bacterial genome was analyzed using QUAST v5.0.2. The results showed that the total genome length of strain H117 was 3.73 Mbp, and the G+C content of the genomic DNA was 70.33%.

[0043] Download microbes from the NCBI website (https: / / www.ncbi.nlm.nih.gov / datasets / genome / ?taxon=2946549). Microbacterium A phylogenetic tree was constructed from the genomes of the type species of the genus. Furthermore, to further clarify the relationship between strain H117 and... Microbacterium algihabitans T The difference between (GCA_032464975.1) was calculated using ANI Calculator (http: / / www.ezbiocloud.net / tools / ani) and Genome-to-GenomeDistance Calculator v3.0 (https: / / ggdc.dsmz.de / ggdc.php#) for strain H117 and the model strain, respectively. Microbacterium algihabitans T (GCA_032464975.1) Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values ​​among genomic sequences. Analysis results indicate that strain H117 is similar to the model strain. Microbacterium algihabitans T The ANI value between (GCA_032464975.1) and (GCA_032464975.1) is 98.66%, and the dDDH value is 88.7%. When the ANI value of two bacterial genomes is less than 95%, they are considered different species. A genome-wide DNA-DNA hybridization value of 70% is the gold standard for prokaryotic species classification. Furthermore, strain H117 constructed using UBCG v3.0 and... Microbacterium algihabitans T The phylogenetic tree of strain H117 (GCA_032464975.1) and the reference type strain of closely related genera was analyzed. The results showed that strain H117 is related to the type species... Microbacterium algihabitansT (GCA_032464975.1) forms an independent phylogenetic branch with a spin value of 100. Figure 2 ).

[0044] Therefore, strain H117 was named Microbacterium algihabitans H117, this strain was deposited on July 27, 2026 at the Guangdong Provincial Microbial Culture Collection Center (GDMCC), located at 5th Floor, Building 59, No. 100 Xianlie Middle Road, Yuexiu District, Guangzhou, Guangdong Province, 510070, China, with accession number GDMCC No: 68734.

[0045] Example 4: Identification of the siderophore-producing capacity of Microbacterium tumefaciens H117 Qualitative detection of siderophore production by the strain: A single colony of the activated strain H117 was inoculated onto a CAS medium plate. CAS medium preparation: 50 mL of Chrome azurol sulphonate (CAS) detection solution was added to 1 liter of basal medium. CAS detection solution preparation method: (1) Prepare 1mM ferric chloride stock solution as solution A: 0.2703g ferric chloride hexahydrate is dissolved in 1L of 10mM hydrochloric acid; (2) Prepare CAS stock solution as solution B: 0.2421g CAS is dissolved in 200mL of deionized water; (3) Prepare hexadecyltrimethylammonium bromide (HTDMA) solution as solution C: Weigh 0.0219g HTDMA and dissolve it in 50mL of water; (4) Prepare piperazine buffer solution as solution D: Weigh 4.3079g anhydrous piperazine and dissolve it in 30mL of water, and adjust the pH to 5.6 with hydrochloric acid; (5) Take 1.5mL of solution A and add 7.5mL of solution B and mix well. While stirring, add 50mL of solution C, then add 30mL of solution D, and finally add 11mL of deionized water to prepare 100mL of CAS detection solution. The basal culture medium consisted of 100g glucose, 20g peptone, 0.5g MgSO4·7H2O, 0.5g CaCl2, 20g agar, and 1000mL ddH2O. After incubation at 28℃ for 48h, the results showed that *Microbacterium tumefaciens* H117 produced a distinct lysis zone on CAS plates, with a pale yellow color. Figure 3 ).

[0046] Example 5: Identification of the ability of *Microbacterium tumefaciens* H117 to mineralize insoluble organic and inorganic phosphorus compounds. A single colony of activated *Microbacterium tumefaciens* H117 was inoculated into TSB liquid medium and cultured at 30°C and 200 rpm for 2 days. 10 μL of the bacterial solution was then added to a poorly soluble organic phosphorus medium or an inorganic phosphorus bacteria medium. The plate was then inverted and cultured at 30°C for 5 days. The phosphorus-solubilizing zone on the plate was observed to determine whether strain H117 had phosphorus-solubilizing ability.

[0047] Insoluble organic phosphorus culture medium: glucose 10 g / L, ammonium sulfate 0.5 g / L, yeast extract 0.5 g / L, sodium chloride 0.3 g / L, potassium chloride 0.3 g / L, magnesium sulfate 0.3 g / L, ferrous sulfate 0.03 g / L, manganese sulfate 0.03 g / L, lecithin 0.2 g / L, calcium carbonate 1.0 g / L, agar 15 g / L. This culture medium was purchased from Qingdao High-tech Industrial Park Haibo Biotechnology Co., Ltd., product number HB8673-1.

[0048] Inorganic phosphorus bacteria culture medium: glucose 10.0 g / L, ammonium sulfate 0.5 g / L, yeast extract 0.5 g / L, sodium chloride 0.3 g / L, potassium chloride 0.3 g / L, magnesium sulfate (MgSO4·7H2O) 0.3 g / L, ferrous sulfate (FeSO4·7H2O) 0.03 g / L, manganese sulfate (MnSO4·4H2O) 0.03 g / L, tricalcium phosphate 5.0 g / L, agar 15.0 g / L, distilled water 1000 mL, pH 6.8-7.2. This culture medium was purchased from Qingdao High-tech Industrial Park Haibo Biotechnology Co., Ltd., product number HB8644.

[0049] The results showed that *Microbacterium tumefaciens* H117 could mineralize insoluble organic and inorganic phosphorus (…). Figure 4 ).

[0050] Example 6: Identification of potassium-solubilizing ability of Microbacterium tumefaciens H117 The activated *Microbacterium tumefaciens* H117 was inoculated onto Aleksandrov Medium using the single-colony inoculation method and incubated at 30°C for approximately 5-7 days. The medium formula is as follows: sucrose 5.0 g / L, disodium hydrogen phosphate 2.0 g / L, magnesium sulfate 0.5 g / L, ferric chloride 0.005 g / L, calcium carbonate 0.1 g / L, potassium feldspar powder 1.0 g / L (or an insoluble potassium source), agar 18.0 g / L, distilled water 1000 mL, pH 7.0-7.5; after preparation, it was sterilized at 121°C for 15 min.

[0051] The results showed that *Microbacterium tumefaciens* H117 exhibited a dissolution zone on the plate, indicating its potassium-solubilizing ability. Figure 5 ).

[0052] Example 7: Identification of nitrogen fixation capacity of *Microbacterium tumefaciens* H117 A single colony of activated *Microbacterium tumefaciens* H117 was inoculated into TSB liquid medium and cultured at 30°C and 200 rpm for 2 days. 10 μL of the bacterial solution was then added to Ashby nitrogen fixation medium. The plate was then inverted and cultured at 30°C for 5 days. The nitrogen fixation ability of strain H117 was determined by observing the lysis zone on the plate.

[0053] Ashby nitrogen-fixing medium (Haibo Biotechnology): Potassium dihydrogen phosphate 0.2 g / L, magnesium sulfate 0.2 g / L, sodium chloride 0.2 g / L, calcium carbonate 5.0 g / L, mannitol 10 g / L, potassium sulfate 0.1 g / L, agar 15.0 g / L, 1000 mL grade III water, pH 7.2. The above culture media were purchased from Haibo Biotechnology Co., Ltd., Qingdao High-tech Industrial Park.

[0054] The results showed that *Microbacterium tumefaciens* H117 has nitrogen-fixing ability ( Figure 6 ).

[0055] Example 8: Evaluation of cellulase production by Microbacterium tumefaciens H117 Cellulose activity assay: Single colonies of strain H117, which was initially screened for degradation activity, were cultured in TSB (ThinPrep) medium with shaking for 24 h. Then, 5 μL of the bacterial culture was inoculated into carboxymethyl cellulose (BM-CMC) medium. The BM-CMC medium formulation consisted of 15 g / L CMC, 2 g / L (NH4)2SO4, 1 g / L KH2PO4, 0.5 g / L MgSO4, and 1 g / L yeast extract as the sole carbon source. The culture was incubated at 30℃ for 5 days. After 5 days of incubation, the colony diameter was measured, and the plates were stained with 1 mg / mL Congo red for 30 min. The Congo red was discarded, and the plates were destained with 1 mol / L NaCl solution for 30 min. The diameter of the clear zone around the colony was observed and measured to determine the strain's ability to degrade cellulose.

[0056] The results showed that *Microbacterium tumefaciens* H117 has the function of degrading cellulose. Figure 7 ).

[0057] Example 9: Evaluation of the ability of *Microbacterium tumefaciens* H117 to resist *Colletotrichum citrinum* anthrax. The antibacterial function of H117 against *Colletotrichum gloeosporioides* was evaluated using the plate confrontation method. Specifically, *Colletotrichum gloeosporioides* was inoculated onto PDA plates and incubated in the dark at 28°C for 3–5 days. The plates were used when the colonies had covered approximately two-thirds of the plate. Antagonistic bacteria also needed to be activated beforehand to ensure consistent viability. Single colonies of bacteria could be picked and inoculated onto PDA plates.

[0058] The five-point confrontation method (pathogen in the center, antagonist bacteria around the perimeter) was used. A cross was drawn at the bottom of the plate, with the center point as the pathogen inoculation site. Using a sterile punch, 9mm diameter mycelial cakes were taken from the edge of activated *Colletotrichum gloeosporioides* colonies and placed upside down in the center of the plate. Four points were marked on a cross line 2.5 cm from the center, serving as inoculation sites for the antagonist bacteria H117. A positive control group (treated with only the pathogen) was set up using the same method. The plates were incubated at 30℃ for 5–7 days. The antibacterial effect of the antagonist bacteria was recorded when the positive control mycelia had just fully colonized the plate. The inhibition rate was calculated using the formula: Inhibition rate % = (Pathogen diameter in control group - Pathogen diameter in treatment group) / Pathogen diameter in control group * 100%.

[0059] The results showed that *Microbacterium tumefaciens* H117 had the ability to inhibit *Colletotrichum gloeosporioides*, with an inhibition rate of 35.3%. Figure 8 ).

[0060] Example 10: Pot experiment on the promotion of tomato growth by *Microbacterium tumefaciens* H117 Tomatoes were selected as the test plants for the growth-promoting pot experiment. Orchard soil was air-dried and sieved through a 2mm sieve, with 500g per pot. Two weeks after sowing, tomato seedlings with good growth uniformity were transplanted and allowed to recover for two days before treatment. Two treatments were set up: CK (control group, i.e., inoculated only with water) and the H117 biocontrol bacteria inoculation experimental group. The experimental group treatment was as follows: strain H117 was fermented in TSB medium for 48 hours, centrifuged at 5000g for 10 minutes, and the bacterial cells were resuspended in sterile water and the OD was adjusted. 600 =2.0, which yielded the bacterial suspension. Using a pipette, the bacterial suspension was applied to the soil from top to bottom in each pot, with 40 mL inoculated each time, for a total of two inoculations, resulting in a cumulative inoculation of 80 mL per pot. Each treatment was set up with 5 replicates. One month later, plant height, aboveground fresh weight and dry weight, and underground fresh weight and dry weight were measured.

[0061] Table 1 Effects of H117 biocontrol bacteria on tomato growth

[0062] Note: The above "*" marks the significance of the difference, "*": (P < 0.05), "**": (P ≤ 0.01), "***": (P ≤ 0.001).

[0063] The results showed that, compared with the control (CK), inoculation with H117 (microbacterium) significantly increased the fresh weight of tomato leaves (by 38.8%) and the fresh weight of roots (by 38.8%). Figure 9 ).

[0064] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A strain of *Microbacterium tumefaciens* ( Microbacterium algihabitans H117, characterized in that, The depository is Guangdong Provincial Microbial Culture Collection Center (GDMCC); the accession number is GDMCC No: 68734.

2. A microbial preparation, characterized in that, Cells and / or cultures of the *Microbacterium tumefaciens* H117 as described in claim 1.

3. The application of the Algal Microbacterium H117 of claim 1 or the microbial preparation of claim 2 in siderogenic carriers.

4. The use of the *Microbacterium tumefaciens* H117 of claim 1 or the microbial preparation of claim 2 in the mineralization of insoluble organic phosphorus and / or the dissolution of insoluble inorganic phosphorus.

5. The application of the *Bacillus algae* H117 of claim 1 or the microbial preparation of claim 2 in nitrogen fixation.

6. The application of the *Microbacterium tumefaciens* H117 of claim 1 or the microbial preparation of claim 2 in potassium solubilization.

7. The use of the *Bacillus algae* H117 of claim 1 or the microbial preparation of claim 2 in the production of cellulase.

8. The *Microbacterium tumefaciens* H117 of claim 1 or the microbial preparation of claim 2 in inhibiting *Colletotrichum gloeosporioides* (… Colletotrichum gloeosporioides Applications during growth.

9. The application of the *Microbacterium tumefaciens* H117 according to claim 1 or the microbial preparation according to claim 2 in promoting plant growth, characterized in that, The plant in question is a tomato.

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