Burkholderia HS5712 for decomposing inorganic phosphorus and organic phosphorus in rhizosphere of camellia oleifera and application of burkholderia HS5712

Abstract

The invention belongs to the technical field of microorganisms, and particularly relates to burkholderia HS5712 for decomposing inorganic phosphorus and organic phosphorus in rhizosphere of camellia oleifera and application of the burkholderia HS5712. The preservation number of the Burkholderia HS5712 is CCTCC (China Center for Type Culture Collection) NO: M 20242861, and the Burkholderia is preserved in the China Center for Type Culture Collection on December 19, 2024. The Burkholderia sp. HS5712 disclosed by the invention can be used for efficiently dissolving inorganic phosphorus (iron phosphate, phosphoric acid and calcium phosphate) and mineralizing organic phosphorus calcium phytate. The bacterium can promote stable phosphorus and medium active phosphorus in different red soil texture gradients to be converted into active phosphorus. Potting and field experiments both prove that the strain can significantly promote the growth and phosphorus absorption of camellia oleifera.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and particularly relates to a Burkholderia HS5712 strain capable of decomposing inorganic and organic phosphorus in the rhizosphere of oil-tea camellia and application thereof. Background Art

[0002] Phosphorus is one of the macronutrients essential for plant growth and development. Plants' absorption of phosphorus mainly depends on the acquisition of soil phosphorus by their roots. Mountain red soil regions have a high proportion of organic phosphorus in the soil, and the mineralization cycle of inorganic phosphorus results in a state of lack or extreme lack of soil phosphorus availability in this region. Free phosphate ions that can be directly absorbed and utilized by plants are easily fixed by iron, aluminum and other ions in acidic red soil to form insoluble phosphates. Furthermore, the poor mobility of phosphorus in the soil exacerbates the difficulty of plant roots in intercepting and absorbing phosphate ions. Therefore, it is necessary to find green and feasible ways to promote the conversion of insoluble phosphorus in the soil phosphorus pool into active phosphorus that can be absorbed by plants.

[0003] Phosphate-solubilizing bacteria (PSB) can mineralize soil organic phosphorus and dissolve insoluble inorganic phosphorus, accelerating the conversion of ineffective soil phosphorus into available phosphorus. Currently, phosphate-solubilizing bacteria have been isolated from rhizosphere soils of various ecological environments (forests, farmlands, grasslands, deserts, and saline-alkali lands) and from trees (e.g., Cunninghamia lanceolata, Eucalyptus sp., and Pinus massoniana). Experimental studies have shown that phosphate-solubilizing strains such as Pseudomonas sp., Burkholderia ZP-4, and Pantoea vagans can significantly improve soil phosphorus availability and promote plant growth. However, most existing phosphate-solubilizing strains primarily dissolve inorganic phosphorus, lacking strains capable of both mineralizing and decomposing organic phosphorus. Furthermore, in practical applications, the phosphate-solubilizing and growth-promoting properties of phosphate-solubilizing strains screened under different habitats are affected by soil pH, which reduces their effectiveness.

[0004] Camellia oleifera Abel. is an important woody edible oil plant grown in red soil regions. However, available phosphorus is generally deficient or extremely deficient in red soil, making it one of the key nutrients that restricts the growth of Camellia oleifera. Summary of the Invention

[0005] The present invention screened a highly efficient phosphate-dissolving bacterium from the rhizosphere of oil-tea camellia in red soil hilly areas. The phosphate-dissolving bacterium is capable of dissolving a variety of inorganic phosphorus and mineralized organic phosphorus. The phosphate-dissolving bacterium has the characteristics of promoting phosphorus conversion and improving the growth and phosphorus absorption of oil-tea camellia. At the same time, it is extremely acid-resistant, is an excellent strain for providing phosphate-dissolving microbial fertilizer, and has the potential to be applied to oil-tea camellia cultivation in red soil areas.

[0006] The efficient phosphate-solubilizing bacteria in the rhizosphere of camellia oleifera of the present invention are named Burkholderia sp. HS5712 (Burkholderia sp. HS5712), which was deposited in the China Center for Type Culture Collection (CCTCC for short, address: Wuhan University, Wuhan, China, postal code 430072) on December 19, 2024, and its deposit number is: CCTCC NO: M 20242861.

[0007] Experiments show that the Burkholderia sp. HS5712 of the present invention can increase the available phosphorus in different red soil textures, accelerate the phosphorus conversion rate, and is applicable to various red soil texture environmental conditions.

[0008] Experiments show that the Burkholderia sp. HS5712 of the present invention can improve the available nutrients in red soil, promote phosphorus circulation, and promote the growth and nutrient absorption of camellia oleifera.

[0009] Experiments show that the Burkholderia sp. HS5712 of the present invention can significantly promote the growth of Camellia oleifera (for example, promote the growth of potted Camellia oleifera seedlings) and phosphorus absorption.

[0010] Experiments show that the Burkholderia sp. HS5712 of the present invention can significantly promote the activation of nutrients in the rhizosphere of oil-tea camellia in the field and improve the absorption of phosphorus.

[0011] Experiments show that the Burkholderia sp. HS5712 of the present invention can simultaneously dissolve inorganic phosphorus (ferric phosphate, aluminum phosphate and calcium phosphate) and mineralize organic phosphorus (calcium phytate), and exhibits strong mineralization ability for calcium phytate and calcium phosphate.

[0012] Experiments show that the Burkholderia sp. HS5712 exhibits extremely strong acid resistance and can grow normally at pH 3.5-6.5.

[0013] Experiments show that the Burkholderia sp. HS5712 can promote the conversion of stable phosphorus and moderately active phosphorus into active phosphorus in different red soil texture gradients.

[0014] The present invention also provides a bacterial agent, comprising the Burkholderia sp. HS5712.

[0015] Specifically, the bacterial agent is a liquid bacterial agent.

[0016] Specifically, the liquid bacterial agent is a bacterial suspension prepared by enriching the Burkholderia sp. HS5712 in LB liquid culture medium and centrifuging the enriched culture medium.

[0017] The present invention also provides application of the Burkholderia sp. HS5712 or the bacterial agent in a growth promoter for oil-tea camellia seedlings.

[0018] The Burkholderia sp. HS5712 of the present invention can be used to prepare a growth-promoting bacterial agent for camellia oleifera.

[0019] The Burkholderia sp. HS5712 of the present invention can dissolve inorganic phosphorus (ferric phosphate, aluminum phosphate, and calcium phosphate) and mineralized organic phosphorus (calcium phytate). Soil inoculation experiments show that Burkholderia sp. HS5712 can significantly increase the available nutrients in red soil and convert residual and stable states into active phosphorus forms, thereby increasing the conversion rate of phosphorus and exerting a phosphorus-dissolving effect under different red soil textures. Potted plant experiments show that Burkholderia sp. HS5712 can improve the photosynthetic capacity of tea leaves, regulate root structure, and reduce the radial transport distance of the roots, thereby increasing the root system's absorption of nitrogen and phosphorus and promoting the growth of tea. In addition, field experiments also show that Burkholderia sp. HS5712 can significantly improve the absorption of nutrients by tea seedlings. Therefore, the Burkholderia sp. HS5712 of the present invention is an excellent phosphate-dissolving strain, which can be used to prepare phosphate-dissolving microbial fertilizer and applied to oil-tea camellia production in red soil areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1This is the colony morphology and phosphate-solubilizing circle of Burkholderia sp. HS5712.

[0021] Figure 2 This is the phylogenetic tree of Burkholderia sp. HS5712.

[0022] Figure 3 This is the phosphate solubilizing characteristic of Burkholderia sp. HS5712.

[0023] Figure 4 This is the phosphorus absorption of field Camellia oleifera by Burkholderia sp. HS5712. DETAILED DESCRIPTION

[0024] To make the above-mentioned objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention are described in detail below. In the following description, specific details of the embodiments are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar modifications without violating the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0025] The culture medium formula used is as follows:

[0026] NBRIP solid culture (g / L): glucose 10g, Ca3(PO4) 25g, MgSO4·7H2O 0.25g, KCl 0.2g, MgCl 2· 7H2O 0.5 g, (NH4)2SO4 0.15 g, agar 20 g. Liquid NBRIP medium does not contain agar.

[0027] LB solid medium (g / L): 10 g tryptone, 10 g NaCl, 5 g yeast extract, 20 g agar. Liquid LB medium does not contain agar.

[0028] Example 1 Screening and identification of phosphate-solubilizing bacteria in the rhizosphere of camellia oleifera

[0029] Rhizosphere soils of four varieties of Camellia oleifera ('Huashuo', 'Huaxin', 'Huajin', and 'Changlin 40') were collected in Liuyang City, Hunan Province. The rhizosphere soils were collected using the three-point sampling method and placed in sterile ziplock bags. The bags were then placed in a convenient ice box and brought back to the laboratory for isolation of phosphate-solubilizing strains. 1 g of fresh soil was accurately weighed and placed in a conical flask containing 99 mL of sterile water. The soil suspension was shaken in a constant temperature shaker at 28°C and 180 rpm for 30 minutes to prepare a soil suspension. After standing for 10 minutes, the soil suspension was diluted in a gradient manner. 0.1 mL of 10 -3 , 10 -4 , 10 -5 The soil dilution was spread onto NBRIP solid culture medium and incubated in a 28°C incubator for 7 days. Strains with a more obvious phosphate solubilization zone were selected for further purification and temporarily stored in LB medium. The purified phosphate-solubilizing strains were inoculated onto NBRIP solid culture medium and incubated in a 28°C incubator for 7 days. The colony diameter (d) and the phosphate solubilization zone diameter (D) were measured using a ruler, and the phosphate solubilization coefficient (SI) was calculated as D / d.

[0030] The present invention uses the plate coating method to obtain 57 phosphate-solubilizing strains with stable phosphate-solubilizing ability from the rhizosphere of four oil-tea camellia varieties, and then selects 12 phosphate-solubilizing bacteria with SI>2.5 and cultures them in NBRIP liquid medium for 4 days on a shaking table. It is determined that the strain HS5 has a strong phosphate-solubilizing ability, and its phosphate-solubilizing circle and colony morphology are as follows: Figure 1 shown.

[0031] The 16S rRNA gene sequence of the phosphate-solubilizing strain HS5 (SEQ NO.1) was compared with the NCBI database and the model strains with high similarity were downloaded to construct the phylogenetic tree. The results showed that ( Figure 2 ): Strain HS5 showed high similarity to Burkholderia pyrrocinia and was identified as Burkholderia sp. and named Burkholderia sp. HS5712. Its 16S rRNA gene sequence has been uploaded to the NCBI database with the accession number PP439505.

[0032] On December 19, 2024, Burkholderia sp. HS5712 was deposited in the China Center for Type Culture Collection (CCTCC, address: Wuhan University, Wuhan, China, Postal Code 430072), and its deposit number is: CCTCC NO: M 20242861.

[0033] The sequence of SEQ NO.1 is as follows:

[0034] gcggcatcct tacacatgca agtcgaacgg cagcacgggt gcttgcacct ggtggcgagt 60

[0035] ggcgaacggg tgagtaatac atcggaacat gtcctgtagt gggggatagc ccggcgaaag 120

[0036] ccggattaat accgcatacg atctacggat gaaagcgggg gaccttcggg cctcgcgcta 180

[0037] tagggttggc cgatggctga ttagctagtt ggtggggtaa aggcctacca aggcgacgat 240

[0038] cagtagctgg tctgagagga cgaccagcca cactgggact gagacacggc ccagactcct 300

[0039] acgggaggca gcagtgggga attttggaca atgggcgaaa gcctgatcca gcaatgccgc 360

[0040] gtgtgtgaag aaggccttcg ggttgtaaag cacttttgtc cggaaagaaa tccttggttc 420

[0041] taatacagcc gggggatgac ggtaccggaa gaataagcac cggctaacta cgtgccagca 480

[0042] gccgcggtaa tacgtagggt gcgagcgtta atcggaatta ctgggcgtaa agcgtgcgca 540

[0043] ggcggtttgc taagaccgat gtgaaatccc cgggctcaac ctgggaactg cattggtgac 600

[0044] tggcaggcta gagtatggca gaggggggta gaattccacg tgtagcagtg aaatgcgtag

[0045] agatgtggag gaatccgat ggcgaaggca gccccctggg ccaatactga cgctcatgca

[0046] cgaaagcgtg gggagcaaac aggregate accctggtag tccacgccct aaacgatgtc 780

[0047] aactagttgt tggggattca tttccttagt aacgtagcta acgcgtgaag ttgaccgcct 840

[0048] ggggagtacg gtcgcaagat taaaactcaa aggaatgac ggggacccgc acaagcggtg

[0049] gatgatgtgg attack tgcaacgcga aaaaccttac ctacccttga catggtcgga

[0050] atcctgctga gaggtgggag tgctcgaaag agaaccgata cacaggtgct gcatggctgt

[0051] cgtcagctcg tgtcgtgaga tgttgggtta agtcccgcaa cgagcgcaac ccttgtcctt 1080

[0052] agttgctacg caagagcact ctaaggagac tgccggtgac aaaccggagg aaggtgggga 1140

[0053] tgacgtcaag tcctcatggc ccttatgggt agggcttcac acgtcataca atggtcggaa

[0054] cagagggttg ccaacccgcg agggggagct aatcccagaa aaccgatcgt agtccggatt 1260

[0055] gcactctgca actcgagtgc atgaagctgg aatcgctagt aatcgcggat cagcatgccg 1320

[0056] cggtgaatac gttcccgggt cttgtacaca ccgcccgtca caccatggga gtgggtttta 1380

[0057] ccagaagtgg ctagtctaac cgcaaggagg acggtcacca cggtaggatt catgactg 1438

[0058] Example 2 Phosphate Solubilization Characteristics and Acid Resistance of Burkholderia sp. HS5712

[0059] Burkholderia sp. HS5712 was inoculated into LB medium and activated and enriched in a shaking incubator at 28°C and 180 rpm. The bacterial solution was then centrifuged in a refrigerated centrifuge at 8000 rpm for 5 min and adjusted to OD 600 =0.6, and inoculated into the same amount of iron phosphate (FePO3), aluminum phosphate (AlPO3) and phytic acid calcium (C6H6Ca6O 24 P6) in NBRIP liquid medium, shake in a shaker at 28°C and 180 rpm for 4 days. The culture suspension was centrifuged at 8000 rpm at 4°C for 5 minutes. 2.5 mL of the supernatant was collected and the available phosphorus content was determined using the molybdenum antimony colorimetric method. Soluble phosphorus content = available phosphorus content in the inoculated culture medium - available phosphorus content in the uninoculated culture medium.

[0060] The acid tolerance of Burkholderia sp. HS5712 was assessed using a series of simulated acidic environments using LB solid plates to determine its adaptability to acidic red soil. The strain was inoculated into LB liquid medium and enriched overnight at 28°C and 180 rpm in a shaking incubator. 10 μL of the bacterial suspension was then inoculated onto LB solid medium at different pH values ​​(3.5, 4.0, 4.5, 5.0, 5.5, 6.0, and 6.5), with three replicates inoculated under the same acidic conditions. The strains were incubated in a 28°C incubator for 48 hours, and the colony diameters were measured with a ruler to assess their adaptability to acidic environments.

[0061] See the results Figure 3 The results showed that the amount of phosphorus solubilized by Burkholderia sp. HS5712 in the culture medium of iron phosphate, aluminum phosphate, calcium phytate and calcium phosphate were 61.47 mg / L, 44.67 mg / L, 490 mg / L and 473.1 mg / L, respectively, indicating that Burkholderia sp. HS5712 has the ability to utilize a variety of insoluble phosphorus sources.

[0062] Table 1 Acid resistance of Burkholderia sp. HS5712

[0063]

[0064] As shown in Table 1, as the pH of the plate decreases, the colony diameter of the strain shows a decreasing trend, but the strain can still grow normally, indicating that Burkholderia sp. HS5712 has a strong acid resistance.

[0065] Example 3 Burkholderia sp. HS5712 regulates the geochemical properties of red soil

[0066] Acidic red soil from the Central South University of Forestry and Technology was excavated and disinfected with carbendazim wettable agent and then covered with film for 5 days. The soil was then passed through a 10-mesh sieve. Hard perlite was then mixed with the soil at volume ratios of 0%, 20%, and 40% (denoted as 0% PR, 20% PR, and 40% PR, respectively) to simulate different soil texture gradients. The mixture was then distributed into seedling pots (12 cm diameter × 14 cm height) for later use.

[0067] Burkholderia sp. HS5712 was inoculated into LB liquid medium for enrichment, centrifuged, and the OD was adjusted with sterile water. 600 A bacterial suspension with a pH of 0.6 was inoculated into the three red soil texture gradients described above, with 10 mL of this suspension inoculated into five pots per treatment, with three replicates. Forty days after inoculation, soil was collected to measure available nutrients (available phosphorus, available potassium, ammoniacal nitrogen, and nitrate nitrogen) and pH. The results are shown in Table 2.

[0068] Table 2 Effects of Burkholderia sp. HS5712 on the geochemical properties of different red soils

[0069]

[0070] Note: HS5 refers to Burkholderia sp. HS5712. *Significant difference (P < 0.5), **Extremely significant difference (P < 0.05). Same below.

[0071] As can be seen from Table 2, the available phosphorus in the three red soil texture gradients increased by 45.9%, 45.34% and 56.0%, the available potassium increased by 19.1%, 14.5% and 6.5%, and the ammonia nitrogen increased by 31.5%, 42.8% and 40.3%. The pH value of the soil inoculated with strain HS5 was significantly reduced under the red soil textures with the addition of 20% PR and 40% PR. This shows that the application of Burkholderia sp. HS5712 can improve the available nutrients in the soil. Example 4 The ability of Burkholderia sp. HS5712 to promote the phosphorus forms in different red soil textures

[0072] The experimental design is consistent with that of Example 3. After 40 days of treatment with Burkholderia sp. HS5712, the soil was air-dried and passed through a 100-mesh sieve. Determination of inorganic phosphorus forms: Accurately weigh 1 g of air-dried soil that has passed through a 100-mesh sieve and extract the inorganic phosphorus forms step by step in a 50 mL centrifuge tube. The following reagents were added in sequence to extract each form of inorganic phosphorus: 0.5 mol / L ammonium fluoride to extract aluminum phosphate (Al-P), and 0.1 mol / L sodium hydroxide solution to extract iron phosphate (Fe-P). Weigh 0.5 g of air-dried soil that has passed through a 100-mesh sieve and extract the inorganic and organic phosphorus forms step by step in a 50 mL centrifuge tube. The assay included anion exchange resin phosphorus (Resin-P), 0.5 mol / L sodium bicarbonate-extracted inorganic phosphorus (NaHCO3-Pi), sodium bicarbonate-extracted organic phosphorus (NaHCO3-Po), 0.1 mol / L sodium hydroxide-extracted inorganic phosphorus (NaOH-Pi), sodium hydroxide-extracted organic phosphorus (NaOH-Po), 1 mol / L dilute hydrochloric acid-extracted inorganic phosphorus (HCl-Pi), and concentrated hydrochloric acid-extracted inorganic phosphorus (conHCl-Pi). The remaining soil sample was digested in a digester using H2SO4-H2O2 to determine residual phosphorus (Residual-P). Organic phosphorus forms were determined by adding sulfuric acid and ammonium persulfate to the inorganic phosphorus extracts at 121°C for 1 hour. The total phosphorus content was then subtracted from the inorganic phosphorus content to obtain the corresponding organic phosphorus content. Since hydrochloric acid-extracted organic phosphorus (HCl-Po) was not detected, it was ignored. All phosphorus forms were determined using the molybdenum antimony colorimetric method. This phosphorus classification system divides plants into reactive phosphorus (Resin-P, NaHCO3-Pi, and NaHCO3-Po), moderately reactive phosphorus (NaOH-Pi and NaOH-Pi), stable phosphorus (HCl-Pi and conHCl-Pi), and residual phosphorus (Residual-P) based on the ease with which plants absorb different forms of phosphorus. The results are shown in Tables 3 and 4.

[0073] Table 3 Effects of Burkholderia sp. HS5712 on inorganic phosphorus components in different red soil textures

[0074]

[0075] Table 4 Effects of Burkholderia sp. HS5712 on phosphorus components in different red soil textures

[0076]

[0077] As shown in Table 3, treatment with the Burkholderia sp. HS5712 strain significantly increased the contents of Fe-P and Al-P. As shown in Table 4, treatment with the Burkholderia sp. HS5712 strain significantly increased the contents of active phosphorus and intermediate active phosphorus (Resin-P, NaHCO3-Pi, and NaOH-Pi). The highest contents of both were found in the red soil texture gradient with 20% PR added. Treatment with the Burkholderia sp. HS5712 strain significantly reduced the contents of stable phosphorus (HCl-P) and residual phosphorus (Residual-P). This indicates that the Burkholderia sp. HS5712 strain can promote the conversion of insoluble phosphorus in the soil into active phosphorus that can be absorbed and utilized by plants.

[0078] Example 5: Burkholderia sp. HS5712 promotes phosphorus absorption in potted tea oil plants

[0079] Seed rooting treatment: Seeds of the improved varieties of Camellia oleifera 'Xianglin 210' and 'Huaxin' were collected and stored in sand, during which the moisture content was kept constant. After the Camellia oleifera seeds took root, they were sown in the following seedling pots containing 3 kg of soil matrix.

[0080] Preparation of seedling medium: dig acidic red soil from Central South University of Forestry and Technology, disinfect it with wettable carbendazim, cover it with film for 5 days, air-dry it, pass the soil through a 10-mesh sieve, add quartz stone with a volume ratio of 20%, mix it well, and divide it into seedling pots with a height × diameter (25 cm × 16 cm).

[0081] Preparation of inoculum: Burkholderia sp. HS5712 was inoculated into LB liquid medium, placed in a shaker at 28°C and 180 rpm for 12 h, centrifuged at 8000 rpm for 5 min, and the OD value was calculated using sterile water. 600 =0.6 bacterial suspension and place it in a 4°C refrigerator for later use.

[0082] Potted seedlings of two oil-tea camellia varieties ('Xianglin 210' and 'Huaxin') were inoculated with Burkholderia sp. HS5712 and a control (CK) inoculation. Each treatment consisted of 15 pots with three replicates, for a total of 180 seedlings. The inoculum was inoculated into the roots of the oil-tea camellia seedlings using the root drench method. Each plant was inoculated with 10 ml of the inoculum, while the CK was supplemented with 10 ml of sterile water. Inoculations were repeated three times every 7 days for a total of 5 months.

[0083] Measurements: Three months after inoculation, photosynthetic parameters, including net photosynthetic rate, stomatal conductance, intercellular carbon dioxide concentration, and transpiration rate, were measured using a portable photosynthetic meter. Chlorophyll content was determined using the acetone extraction method. Five months after treatment, seedling height and ground diameter were measured using a ruler and vernier caliper. Plants were harvested at harvest time to measure biomass. Root morphology was determined using a root scanner. Roots and leaves were digested with sulfuric acid and hydrogen peroxide, and nitrogen and phosphorus content was determined using a fully automated discontinuous chemical analyzer (SmartChem200). Root tip specimens were prepared using paraffin sections, and root tip diameter and vascular bundle diameter were measured using an optical microscope.

[0084] Growth indices, photosynthetic parameters, root morphological structure indices, and nutrient absorption indices are shown in Tables 5, 6, 7, and 8.

[0085] Table 5 Effect of Burkholderia sp. HS5712 on the growth of Camellia oleifera

[0086]

[0087] Table 6 Effects of Burkholderia sp. HS5712 on photosynthesis and chlorophyll in tea leaves

[0088]

[0089] Table 7 Effects of Burkholderia sp. HS5712 on the morphology and structure of Camellia oleifera roots

[0090]

[0091] Table 8 Effect of Burkholderia sp. HS5712 on nutrient absorption of Camellia oleifera

[0092]

[0093] As shown in Table 5, Burkholderia sp. HS5712 significantly increased the seedling height and ground diameter of 'Xianglin 210' and 'Huaxin' by 6.03% to 6.96% and 8.08% to 9.26%, respectively. Except for the significantly higher aboveground fresh weight of 'Xianglin 210' than the CK treatment, no other significant differences were observed, but all treatments were higher than the CK treatment.

[0094] As shown in Table 6, inoculation with Burkholderia sp. HS5712 increased leaf photosynthetic parameters and chlorophyll content. Specifically, Burkholderia sp. HS5712 significantly increased the net photosynthetic rate, stomatal conductance, and intercellular carbon dioxide concentration in the leaves of 'Xianglin 210' by 11.89%, 60.55%, and 11.13%, respectively.

[0095] As shown in Table 7, inoculation with Burkholderia sp. HS5712 increased the root length, root tip number and vascular bundle / root tip diameter of Camellia oleifera, with increases ranging from 6.02% to 115.77%, 22.7% to 75.93% and 14.28% to 18.43, respectively.

[0096] Table 8 shows that inoculation with Burkholderia sp. HS5712 increased phosphorus uptake by tea leaves and accumulation in their leaves. Compared to the CK treatment, phosphorus content in tea leaves increased by 14.69% to 28.49%, while that in roots ranged from 2.44% to 29.36%. Nitrogen content in the roots and leaves of 'Xianglin 210' increased by 5.02% to 153.78%. This suggests that Burkholderia sp. HS5712 can improve nutrient absorption and transport efficiency in tea oil plants by regulating root morphology and reducing radial root transport distance, thereby promoting growth.

[0097] Example 6: Burkholderia sp. HS5712 promotes phosphorus absorption in tea oil plants

[0098] Appropriate amounts of Burkholderia sp. HS5712 were inoculated into LB liquid medium and cultured overnight in a shaking incubator at 28°C and 180 rpm. The fermentation broth was centrifuged at 8000 rpm for 5 minutes, and the cells were resuspended in sterile water to prepare a bacterial suspension, which was then temporarily refrigerated at 4°C until use. The experimental plot was located in the oil-tea camellia cultivation area of ​​Zhechong Town, Liuyang City, Hunan Province (113°33′51″, 28°3′46″). Three-year-old, healthy, and uniformly grown oil-tea camellia trees, 'Changlin 40', were selected for inoculation. The experimental treatments included the inoculant Burkholderia sp. HS5712 and a blank control (CK). The inoculant was inoculated into the roots of saplings using the root drench method, with 100 mL of inoculant per plant. The CK treatment was treated with an equal amount of sterile water. Six Camellia oleifera saplings were inoculated in each treatment, with three replicates. Five months after inoculation, Camellia oleifera leaf and rhizosphere soil samples were collected to determine leaf total phosphorus and rhizosphere soil available nutrient content.

[0099] Table 9 Effects of Burkholderia sp. HS5712 on nutrients and activity in the rhizosphere soil of Camellia oleifera in the field

[0100]

[0101] As shown in Table 9, the inoculation of Burkholderia sp. HS5712 significantly increased the available phosphorus, alkaline phosphatase activity and phosphorus activation coefficient in the rhizosphere soil of Camellia oleifera, increasing by 105.50%, 206.50% and 33.49% respectively. Figure 4 It can be seen that the fungus significantly improved the absorption of phosphorus by Camellia oleifera in the field, with an increase of 34.00%.

[0102] In summary, for the Burkholderia sp. HS5712 screened by the present invention, the phosphate solubilizing ability of the strain HS5 was evaluated based on liquid culture and soil culture. It was shown that the strain can dissolve a variety of insoluble inorganic phosphorus and mineralized organic phosphorus, promote phosphorus conversion, confirm the efficient phosphate solubilizing effect of Burkholderia sp. HS5712, and can play a role in promoting phosphorus activation under three red soil textures. Potted plant experiments showed that Burkholderia sp. HS5712 may promote nutrient absorption and growth of Camellia oleifera by regulating root morphology and structure. In addition, further field inoculation experiments showed that it can promote the absorption of phosphorus by Camellia oleifera by activating rhizosphere nutrients.

[0103] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. Burkholderia sp. HS5712, whose deposit number is: CCTCC NO: M20242861.

2. A bacterial agent, characterized in that The invention comprises the Burkholderia sp. HS5712 as claimed in claim 1.

3. The bacterial agent according to claim 2, characterized in that The bacterial agent is a liquid bacterial agent.

4. The bacterial agent according to claim 3, characterized in that The liquid bacterial agent is a bacterial suspension prepared by enriching the Burkholderia sp. HS5712 in LB liquid culture medium and centrifuging the enriched Burkholderia sp. HS5712.

5. Use of the Burkholderia sp. HS5712 described in claim 1 or the bacterial agent described in any one of claims 2 to 4 in the preparation of an oil-tea seedling growth promoter.

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