Burkholderia sp. SX-J6 and application thereof in soil improvement in fragile area

Abstract

The invention belongs to the technical field of microorganisms, and particularly relates to burkholderia sp. SX-J6 and application thereof in soil improvement in fragile areas. The invention provides a strain of Burkholderia sp. SX-J6, and the preservation number is CGMCC (China General Microbiological Culture Collection Center) NO.31723. The Burkholderia sp. SX-J6 provided by the invention has saline-alkaline resistance, can effectively survive in a matrix without an organic carbon source, has carbon sequestration capacity, can decompose inorganic potassium in the matrix, has potassium dissolving capacity, and also can produce indoleacetic acid at high yield. The Burkholderia sp. SX-J6 provided by the invention can be used for improving the soil in the fragile area, especially improving the soil in the photovoltaic field area in the fragile area.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and particularly relates to a Burkholderia SX-J6 strain and application thereof in soil improvement in fragile areas. Background Art

[0002] In the soil of fragile areas, plants have a more urgent need for potassium, because potassium helps improve plant resistance, promote root growth, and increase photosynthesis efficiency. However, the potassium in the soil of fragile areas is mostly mineral potassium and non-exchangeable potassium, which is not easily used directly by plants.

[0003] Soil microorganisms live in the soil and participate in the synthesis and decomposition of soil organic matter, changing soil nutrient conditions by decomposing organic matter and promoting nutrient cycling. Potassium-solubilizing microorganisms can convert potassium resources that are difficult to utilize into effective potassium that can be absorbed by plants by secreting organic acids, enzymes or other metabolites, thereby increasing the effective potassium content in the soil. However, the potassium-solubilizing effect of existing potassium-solubilizing microorganisms is not significant and cannot meet actual needs. Summary of the invention

[0004] The purpose of the present invention is to provide a Burkholderia SX-J6 and its application in soil improvement in fragile areas. The provided Burkholderia is salt-alkali resistant, has the ability to fix carbon and release potassium, and can produce a high amount of indoleacetic acid, so as to improve the soil in fragile areas, especially the soil in photovoltaic fields in fragile areas.

[0005] The present invention provides a Burkholderia strain ( Burkholderia sp. )SX-J6, the collection number is CGMCCNO.31723.

[0006] The present invention also provides a bacterial agent, the active ingredient of the bacterial agent includes the Burkholderia SX-J6 described in the above technical solution.

[0007] Preferably, the concentration of Burkholderia SX-J6 in the bacterial agent is 1×10 6 ~1×10 8 CFU / mL.

[0008] The present invention also provides the use of the Burkholderia SX-J6 or the bacterial agent described in the above technical solution in improving soil in fragile areas and / or preparing indoleacetic acid.

[0009] Preferably, the fragile zone soil includes fragile photovoltaic field zone soil, which improves plant quality.

[0010] Preferably, the fragile zone soil improvement includes increasing the available potassium content in the fragile zone soil.

[0011] The present invention also provides a method for preparing indoleacetic acid, comprising the following steps: The Burkholderia SX-J6 or the bacterial agent described in the above technical solution is inoculated into a culture medium containing L-tryptophan, and fermented to obtain a fermentation liquid; the fermentation liquid contains indoleacetic acid.

[0012] Preferably, the fermentation culture temperature is 29-39° C., the rotation speed is 170-200 rpm, and the time is 36-60 h.

[0013] The present invention also provides a method for increasing the effective potassium content in the soil of the fragile zone, and the Burkholderia SX-J6 or the bacterial agent described in the above technical solution is inoculated into the soil of the fragile zone.

[0014] Preferably, the content of mineral potassium in the soil of the fragile zone is 18626.97~22744.30 μg / g, and the concentration of non-exchangeable potassium is 744.41~1072.48 μg / g.

[0015] Beneficial effects: The present invention provides a strain of Burkholderia SX-J6, with a deposit number of CGMCC NO.31723. The Burkholderia SX-J6 provided by the present invention has salt-alkali tolerance, can effectively survive in a matrix without an organic carbon source, has carbon fixation ability, and the strain can decompose inorganic potassium in the matrix, has the ability to decompose potassium, and can also produce high indoleacetic acid. The Burkholderia SX-J6 provided by the present invention can be used to improve soil in fragile areas, especially to improve soil in photovoltaic fields in fragile areas.

[0016] Biological deposit information Burkholderia SX-J6, classified as Burkholderia Burkholderia sp. , deposited on August 23, 2024 at the General Microbiology Center of China Culture Collection Administration, address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Postal Code: 100101, and the deposit number is CGMCC NO.31723. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0018] Figure 1 This is the colony morphology of SX-J6; Figure 2 This is the phylogenetic tree of Burkholderia SX-J6; Figure 3 OD of Burkholderia SX-J6 under different NaCl concentrations (a) and different pH environments (b) 600 value; Figure 4 This is the quantitative test result of potassium solubilization performance of Burkholderia SX-J6; Figure 5 It is the quantitative test result of IAA production performance of Burkholderia SX-J6; Figure 6 The results of photosynthesis index detection of sunflower under the treatment of Burkholderia SX-J6; * indicates P <0.05; *** indicates P <0.001; Figure 7 The potassium content test results of sunflower plants treated with Burkholderia SX-J6; * indicates P <0.05; *** indicates P <0.001. DETAILED DESCRIPTION

[0019] The present invention provides a Burkholderia strain ( Burkholderia sp. )SX-J6, the collection number is CGMCCNO.31723.

[0020] The Burkholderia SX-J6 described in the present invention is a strain isolated from the soil between fixed panels in a large-scale centralized photovoltaic field in Daqing, Heilongjiang Province. The colony produced by the strain on the solid culture medium is round or approximately round in shape, the colony is relatively convex, the texture is uniform, opaque, the surface is smooth, moist, shiny, and grayish white, and the colony edges are neat ( Figure 1 ). The nucleotide sequence of 16S rRNA of Burkholderia SX-J6 of the present invention is shown in SEQ ID NO:1.

[0021] The present invention also provides a bacterial agent, wherein the active ingredient of the bacterial agent includes the Burkholderia SX-J6 described in the above technical solution. As an embodiment, the concentration of Burkholderia SX-J6 in the bacterial agent of the present invention is 1×10 6 ~1×10 8 CFU / mL; As another embodiment, the concentration of Burkholderia SX-J6 in the bacterial agent of the present invention is 5×10 6 ~5×10 7 CFU / mL; As another embodiment, the concentration of Burkholderia SX-J6 in the bacterial agent of the present invention is 1×10 7 CFU / mL.

[0022] The present invention also provides the use of the Burkholderia SX-J6 or the bacterial agent described in the above technical solution in improving soil in fragile areas and / or preparing indoleacetic acid.

[0023] As an embodiment, the soil in the fragile area includes soil in the fragile photovoltaic field area. As an embodiment, the basic physical and chemical properties of the soil in the fragile photovoltaic field area of ​​the present invention are: bulk density is 1.35-1.55g / cm 3 The average water content is 33.2%, the pH value is 9.86~10.51, and the cationic components of soluble salts include Na + , Fe 2+ , Ca 2+ Mg 2+ , K + , Mn 2+ 、Zn 2+ and Cu 2+ , total salt content is 8108.43μg / g.

[0024] As an embodiment, the fragile zone soil improvement includes increasing the effective potassium content in the fragile zone soil and improving the plant quality. As an embodiment, the improving plant quality of the present invention includes increasing the photosynthetic capacity index of plants in the fragile zone soil.

[0025] The present invention also provides a method for preparing indoleacetic acid, comprising the following steps: inoculating the Burkholderia SX-J6 or the bacterial agent described in the above technical solution into a culture medium containing L-tryptophan, performing fermentation culture, and obtaining a fermentation liquid; the fermentation liquid contains indoleacetic acid.

[0026] The present invention inoculates the Burkholderia SX-J6 or the bacterial agent described in the above technical solution into a culture medium containing L-tryptophan, performs fermentation culture, and obtains a fermentation liquid. As an embodiment, the temperature of the fermentation culture is 29-39°C; as another embodiment, the temperature of the fermentation culture is 30-35°C; as another embodiment, the temperature of the fermentation culture is 35°C. As an embodiment, the rotation speed of the fermentation culture is 170-200rpm; as another embodiment, the rotation speed of the fermentation culture is 180-200rpm; as another embodiment, the rotation speed of the fermentation culture is 180rpm. As an embodiment, the fermentation culture time is 36-60h; as another embodiment, the fermentation culture time is 36-48h; as another embodiment, the fermentation culture time is 48h.

[0027] As an embodiment, the inoculation amount is 5.0×10 6 CFU / mL~5.0×10 7 CFU / mL; as another embodiment, the inoculation amount is 1.0×10 7CFU / mL. As one embodiment, the mass concentration of L-tryptophan in the culture medium containing L-tryptophan is 0.06-0.15wt.%; as another embodiment, the mass concentration of L-tryptophan in the culture medium containing L-tryptophan is 0.1wt.%.

[0028] As an embodiment, after obtaining the fermentation liquid, the present invention performs solid-liquid separation on the fermentation liquid and collects the liquid portion. As an embodiment, the solid-liquid separation of the present invention includes centrifugation. As an embodiment, the rotation speed of the centrifugation of the present invention is 6000-8000 rpm; as another embodiment, the rotation speed of the centrifugation of the present invention is 7000 rpm. As an embodiment, the time of the centrifugation of the present invention is 8-15 minutes; as another embodiment, the time of the centrifugation of the present invention is 10 minutes.

[0029] The present invention also provides a method for increasing the effective potassium content in the soil of the fragile zone, and the Burkholderia SX-J6 or the bacterial agent described in the above technical solution is inoculated into the soil of the fragile zone.

[0030] As an implementation method, the basic physical and chemical properties of the soil in the fragile area are: bulk density ≥ 1.35 g / cm 3 The average water content is 33.2%, the pH value is 9.86~10.51, and the cationic components of soluble salts include Na + , Fe 2+ , Ca 2+ Mg 2+ , K + , Mn 2 + 、Zn 2+ and Cu 2+ , total salt content 8108.43 μg / g. As an embodiment, the content of mineral potassium in the soil of the fragile zone is 9012.97~12490.30 μg / g, and the concentration of non-exchangeable potassium is 744.41~1072.48 μg / g. As an embodiment, the inoculation amount is 5.0×10 6 CFU / mL~5.0×10 7 CFU / mL; as another embodiment, the inoculation amount is 1.0×10 7 CFU / mL.

[0031] In order to further illustrate the present invention, a Burkholderia SX-J6 provided by the present invention and its application in soil improvement in fragile areas are described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0032] Solid medium without organic carbon source: Na 2 HPO 4 0.5 g / L, KH 2 PO 4 0.5 g / L, MgSO 4 0.3 g / L, CaCl 2 0.2 g / L, NaHCO 3 0.5 g / L, NH 4 Cl 0.5 g / L, NaNO 3 0.25 g / L, NaCl 0.4 g / L, trace element solution 2 mL / L and agar 20 g / L, pH 7.0; the trace element solution composition is: FeCl 2 0.3 g / L, FeSO 4 7H 2 O0.3 g / L, MnSO 4 ·H 2 O 0.15 g / L, ZnSO 4 7H 2 O 0.25 g / L and CoCl 2 0.2 g / L, dilute to 1 L and sterilize through 0.22 μm filter membrane; LB solid medium: 10 g of tryptone, 5 g of yeast extract, 10 g of sodium chloride (NaCl), 15 g of agar powder, dilute to 1000 mL with deionized water, natural pH is 7, stir evenly, sterilize at 121°C for half an hour, and cool to room temperature after sterilization; LB liquid medium: 10 g of tryptone, 5 g of yeast extract, 10 g of sodium chloride (NaCl), dilute to 1000 mL with deionized water, natural pH is 7, stir evenly, sterilize at 121°C for half an hour, and cool to room temperature after sterilization; Potassium-dissolving liquid medium: 5g glucose, 0.5g yeast powder, 0.5g ammonium sulfate, 0.3g magnesium sulfate, 2g disodium hydrogen phosphate, 0.03g ferrous sulfate, 0.03g manganese sulfate, 2g inorganic potassium source obtained in Example 3, dilute to 1000mL with distilled water, stir evenly, heat to promote dissolution. Adjust pH to 7.0-7.2, sterilize at 121℃ for 15min, and set aside; Solid culture medium containing L-tryptophan: 10 g of tryptone, 5 g of yeast extract, 10 g of sodium chloride (NaCl), 15 g of agar powder, dilute to 1000 mL with deionized water, natural pH is 7, stir evenly, sterilize at 121°C for half an hour, cool to room temperature after sterilization, then add 0.1% L-tryptophan solution to the culture medium, natural pH; Liquid culture medium containing L-tryptophan: 10 g of tryptone, 5 g of yeast extract, 10 g of sodium chloride (NaCl), dilute to 1000 mL with deionized water, stir evenly, sterilize at 121°C for half an hour, cool to room temperature after sterilization, and then add 0.1 wt.% L-tryptophan solution to the culture medium, natural pH.

[0033] Example 1 Isolation and identification of strains 1. Collect soil from the surface layer of 0-20 cm between fixed panels in a centralized large-scale photovoltaic field in Daqing City, Heilongjiang Province. Take 10.0 g of the collected soil, add it to 100 mL of sterilized water, and place it on a shaker for shaking (180 rpm, 30 min) to make a soil suspension. Then dilute the soil suspension in a 10-fold gradient to 10 -5 times, take 0.2 mL of the soil dilution, apply it to the solid culture medium without organic carbon source, and culture it upside down at 30℃ for 4 days.

[0034] 2. Select the colonies with good morphology, growth potential and fast growth rate in the solid medium without organic carbon source, purify them on new LB solid medium by inoculation loop streak method for multiple times until pure culture, and screen out a target strain, numbered SX-J6, with round or nearly round colonies, light yellow, smooth, moist, shiny surface, neat edges, and different sizes ( Figure 1 ).

[0035]

[0036] 4. Using the NCBI database, BLAST analysis was performed based on the 16S rRNA gene sequence of strain SX-J6, and a phylogenetic tree was constructed. The results showed that strain SX-J6 was Burkholderia paludis MSh1 The 16S rRNA gene sequence of Burkholderia contaminans J2956 The homology of the 16S rRNA gene sequence of Burkholderia lata 383 The 16S rRNA gene sequence of Burkholderia arboris R-24201 The 16S rRNA gene sequence of the genus NR_042634.1 is 99.78% homologous to Burkholderia aenigmatica LMG 13014 The homology of the 16SrRNA gene sequence of strain SX-J6 (accession number NR_174230.1) is 99.64%. Burkholderia paludis and Burkholderia contaminans The closest phylogenetic relationship ( Figure 2 ), combined with its bacterial morphology and colony characteristics ( Figure 1 ), the strain was identified as Burkholderia ( Burkholderia sp. ), named Burkholderia Burkholderia sp. )SX-J6 and made a biological deposit.

[0037] Example 2 Study on the Salt-Alkali Tolerance of Burkholderia SX-J6 1. Pick the Burkholderia SX-J6 isolated in Example 1, inoculate it into 10 mL of fermentation medium (Tryptone 10 g / L, yeast extract 5 g / L, sodium chloride (NaCl) 10 g / L), and culture it at 35 ° C and 180 rpm for 48 h to obtain SX-J6 seed liquid.

[0038] 2. Effect of NaCl concentration on Burkholderia SX-J6 The SX-J6 seed solution was inoculated into 10 mL of LB liquid culture medium (pH 7.0) with different NaCl concentrations (0wt.%, 2wt.%, 4wt.%, 6wt.%, 8wt.%, 10wt.%, 12wt.%, 14wt.%, 16wt.% and 18wt.%) at a volume ratio of 2%, and cultured at 35°C, 170 rpm for 4 d. The bacterial solution at the end of the culture was taken and the OD was measured using a spectrophotometer. 600The values ​​were determined, and preliminary analysis was performed using Microsoft Excel Office 2016 software. R language (R v4.1.2) was used for drawing. The results are shown in Figure 3 As shown in a.

[0039] according to Figure 3 As can be seen in a, when 6wt.% or less NaCl is added to the LB liquid medium, the activity of Burkholderia SX-J6 is good, and when the NaCl concentration is further increased to 12wt.%, although its activity decreases, it still has a certain activity. Burkholderia SX-J6 has strong salt tolerance.

[0040] 3. Effect of pH on Burkholderia SX-J6 The SX-J6 seed solution was inoculated into 10 mL of LB liquid culture medium with different pH values ​​(2.8, 3.4, 4.2, 5.0, 5.8, 6.6, 7.4, 8.2, 9.0, and 10.0) at a volume ratio of 2%, and cultured at 35°C and 170 rpm for 4 days. The bacterial solution at the end of the culture was taken and the OD value was measured using a spectrophotometer. 600 The values ​​were determined, and preliminary analysis was performed using Microsoft Excel Office 2016 software. R language (R v4.1.2) was used for drawing. The results are shown in Figure 3 As shown in b.

[0041] according to Figure 3 As can be seen in b, the activity of Burkholderia SX-J6 was good when the pH of LB liquid medium was ≥5.0, and the activity was the best when the pH was 7.0 (initial LB medium). 600 =1.542, when 7.4≤pH≤10.0, the activity will decrease slightly with the increase of alkalinity, but still maintain a high activity intensity. When pH<5.0, its activity is poor. Burkholderia SX-J6 has strong alkali resistance.

[0042] Example 3 Potassium-dissolving ability test of Burkholderia SX-J6 1. Preparation of Inorganic Potassium Source Select potassium feldspar powder and pass it through a 180-mesh sieve. Soak it in deionized water overnight, then wash it thoroughly with deionized water for 3 to 5 times to remove the soluble potassium therein, and dry it in the shade for later use.

[0043] 2. Potassium-dissolving performance test (1) The Burkholderia SX-J6 isolated in Example 1 was selected and inoculated into 10 mL of LB liquid culture medium. The culture was carried out at 35°C and 170 rpm for 4 days to obtain 5.0×10 8 ~8.0×108 CFU / mLSX-J6 seed solution.

[0044] (2) The SX-J6 seed liquid was inoculated into 10 mL of potassium-degrading liquid medium at a volume ratio of 2%, and cultured at 35°C and 170 r / min for 4 days. After the culture was completed, the supernatant was taken and centrifuged at 4000 rpm for 10 min in a low-speed centrifuge to remove the bacteria and insoluble impurities. It was then mixed evenly with sodium tetraphenylborate (NaTPB) solution and allowed to stand for a period of time. A white precipitate was found to be generated, indicating that Burkholderia SX-J6 can decompose potassium in inorganic potassium sources.

[0045] 3. Potassium-dissolving ability test (1) Configuration of standard curve Sodium tetraphenylborate (NaTPB) was used to prepare a 0.05 mol / L NaTPB aqueous solution. Potassium chloride was used to prepare 0 mg / L, 10 mg / L, 20 mg / L, 50 mg / L, and 100 mg / L potassium salt standard solutions. 5 mL of potassium standard solution was added to a colorimetric tube. NaTPB aqueous solution was added in an equal volume ratio. The colorimetric tube was gently shaken to mix the solution evenly. The solution was allowed to stand for 10 to 15 minutes until a white precipitate was completely formed. The absorbance of the reaction solution was measured at a wavelength of 620 nm. The absorbance was proportional to the concentration of potassium ions in the solution. A standard curve that met the accuracy requirements was drawn. The equation was y = 0.0083x + 0.0126. The standard curve fit was R 2 =0.999( Figure 4 ).

[0046] (2) The SX-J6 seed liquid was inoculated into 10 mL of potassium-dissolving liquid culture medium at a volume ratio of 2%, and cultured at 35°C and 170 r / min for 4 days. After the culture was completed, the supernatant was taken and centrifuged at 4000 rpm for 10 min in a low-speed centrifuge to remove the bacteria and insoluble impurities. Then 5 mL of the Burkholderia SX-J6 culture supernatant was added to a colorimetric tube. NaTPB aqueous solution was added according to an equal volume ratio and the colorimetric tube was gently shaken to mix the solution evenly. The solution was allowed to stand for 10 to 15 minutes until a white precipitate was completely formed. The absorbance of the reaction solution was measured at a wavelength of 620 nm and substituted into the standard curve to quantitatively analyze the potassium content in the Burkholderia SX-J6 culture supernatant. The results showed that the OD value of the reaction product of the Burkholderia SX-J6 culture supernatant and the NaTPB aqueous solution was 0.0447 W / m. 620 The values ​​were 0.651 and 0.687 respectively, and the quantitative analysis of potassium content was 76.92 mg / L and 81.25 mg / L respectively ( Figure 4 ). The original data of this embodiment was preliminarily sorted using Microsoft Excel Office 2016 software. The experimental results were plotted using R language (R v4.1.2).

[0047] Example 4 Functional detection of IAA production by Burkholderia SX-J6 1. Configuration of standard curve Weigh 10 mg of IAA standard accurately, dissolve it with a small amount of ethanol, and then dilute it to 100 mL with distilled water (the concentration is 0.1 g / L) as IAA stock solution (mother solution); take 0, 2.5, 5, 7.5, and 10 mL of the mother solution and dilute it to a 25 mL volumetric flask to prepare 0, 10, 20, 30, and 40 mg / L standard solutions. Take an appropriate amount of IAA standard solution and mix it with an equal volume of Salkowski colorimetric solution. After shaking, let it stand at room temperature in the dark for 30 minutes, and measure its absorbance value (OD) at a wavelength of 530 nm. 530 ), with the concentration of IAA standard solution as the horizontal axis and the corresponding absorbance as the vertical axis, the IAA standard curve that meets the accuracy requirements is drawn. The results show that the equation is y=0.031x+0.024, and the standard curve fitting degree R 2 =0.998( Figure 5 ).

[0048] 2. Pick the Burkholderia SX-J6 isolated in Example 1 and inoculate 1 ml of the solution with a concentration of 1.0×10 8 CFU / mL of SX-J6 seed liquid was placed in 10mL of liquid culture medium containing L-tryptophan, and cultured on a constant temperature shaker at 35°C and 180rpm for 48h. After that, the fermentation liquid was taken out and the liquid culture medium containing L-tryptophan without inoculation was used as the control. The fermentation liquid was centrifuged at 7000rpm for 10min, and the supernatant was retained for standby. 2mL of supernatant was taken out with a pipette, and an equal volume of Salkowski colorimetric solution was added, and the mixture was fully mixed in a white ceramic plate, and allowed to stand at room temperature and away from light for 30min. If the mixed solution turns pink, it indicates that the strain has the ability to produce IAA, and the redder the color, the greater the intensity of production. On the contrary, if the strain solution and the blank control do not show a significant red color change, and the standard IAA concentration solution turns red, it indicates that the strain does not have the ability to produce IAA. The results show that the fermentation supernatant of Burkholderia SX-J6 reacts with the Salkowski colorimetric solution to show red, indicating that it has the ability to produce IAA.

[0049] After standing, the absorbance value (OD 530), substituted into the standard curve, quantitatively analyzed the IAA production of Burkholderia SX-J6, and repeated 4 times. The results showed that the absorbance values ​​of the fermentation supernatant of Burkholderia SX-J6 at a wavelength of 600nm were 1.403, 1.551, 1.774 and 1.884, respectively; the absorbance values ​​of the fermentation supernatant of Burkholderia SX-J6 and the Salkowski colorimetric mixture at a wavelength of 530nm were 0.177, 0.193, 0.235 and 0.284, respectively, and the corresponding IAA production was 4.94, 5.45, 6.81 and 8.39 mg / L, respectively ( Figure 5 ). The original data of this embodiment was preliminarily sorted using Microsoft Excel Office 2016 software. The experimental results were plotted using R language (R v4.1.2).

[0050] Example 5 Effects of Burkholderia SX-J6 on Photosynthetic Capacity of Sunflower 1. Pick the Burkholderia SX-J6 isolated in Example 1 and inoculate it into 10 mL of fermentation medium (10 g / L tryptone, 5 g / L yeast extract, 10 g / L sodium chloride (NaCl)). Cultivate at 35°C and 180 rpm for 48 h to obtain SX-J6 seed solution. Dilute the SX-J6 seed solution to a concentration of 1.0 × 10 6 , 1.0×10 7 , 1.0×10 8 Burkholderia SX-J6 bacterial suspension with three concentration gradients of CFU / mL.

[0051] 2. Preparation of Inorganic Potassium Source Select potassium feldspar powder and pass it through a 180-mesh sieve. Soak it in deionized water overnight, then wash it thoroughly with deionized water for 3 to 5 times to remove the soluble potassium therein, and dry it in the shade for later use.

[0052] 3. Configuration of cultivation medium Peat soil and vermiculite were mixed in a volume ratio of 2:1 to obtain a soil matrix, wherein the mass ratio of peat soil to vermiculite was 1.05:0.45. Potash feldspar powder treated in step 2 was added at 0.2% of the mass of the soil matrix, mixed evenly, and sterilized at 121°C for 2 hours, and then air-dried at room temperature in an independent, clean environment to obtain a cultivation matrix.

[0053] 4. Sunflower seed treatment Select sunflower seeds (Black Three-brow Sunflower, registration number GPD Sunflower (2018) 620617) with full grains, no mildew, uniform size, no wormholes, and no damage, rinse the surface dust with sterile water, then wipe with 75% v / v ethanol for 16-20 seconds, then soak in 0.1wt.% potassium permanganate solution for 10 minutes, and finally wash with sterile water 5-8 times. Take 100mL of the sterile water from the last rinse and spread it on the peptone solid culture medium, invert and culture at a constant temperature for 48 hours, observe whether there is colony formation on the surface of the culture medium to verify the thoroughness of the sunflower surface disinfection, and set aside.

[0054] 5. Put the cultivation medium into a 0.4L flowerpot, wherein the masses of peat soil and vermiculite are 1.05kg / pot and 0.45kg / pot respectively, sow the sunflower seeds at a depth of 0.5cm, and culture them in a plant incubator. The plant incubator is set at 30℃ during the day, 15000Lux for 12h, and a relative humidity of 80%; the dark temperature is 12h, the temperature is set at 25℃, and the relative humidity is 75%.

[0055] After the seeds germinated, they were randomly divided into 4 treatment groups, each with 3 replicates, and the following treatments were performed: CK (RO water): Use 50 mL of RO water to irrigate the roots of sunflower plants, and add the same amount of RO water again 10 days and 20 days after the first addition of RO water; Low concentration J6 bacterial solution: 50 mL 1.0×10 6 CFU / mL of Burkholderia SX-J6 suspension was watered to the roots of sunflower plants, and the same concentration of Burkholderia SX-J6 suspension was added again 10 days and 20 days after the first addition of Burkholderia SX-J6 suspension; Medium concentration J6 bacterial solution: 50 mL 1.0×10 7 CFU / mL of Burkholderia SX-J6 suspension was watered to the roots of sunflower plants, and the same concentration of Burkholderia SX-J6 suspension was added again 10 days and 20 days after the first addition of Burkholderia SX-J6 suspension; High concentration J6 bacterial solution: 50 mL 1.0×10 8 CFU / mL of Burkholderia SX-J6 suspension was watered to the roots of sunflower plants, and the same concentration of Burkholderia SX-J6 suspension was added again 10 days and 20 days after the first addition of Burkholderia SX-J6 suspension; The chlorophyll content of sunflower was measured 3 days after the last addition of bacterial solution to each treatment group. Statistical tests were performed to determine whether there were significant differences in the relative chlorophyll content of sunflowers between different experimental groups. After data analysis, R language (Rv4.1.2) was used to draw the graph. The results are shown in the figure. Figure 6 shown.

[0056] according to Figure 6 It can be seen that the CK group and the low-concentration J6 bacterial solution (1.0×10 6 CFU / mL), medium concentration J6 bacterial solution (1.0×10 7 CFU / mL and high concentration J6 bacterial solution (1.0×10 8 CFU / mL) were 25.60, 27.27, 28.24 and 29.38 respectively. There was no significant difference in the relative chlorophyll content of sunflowers in the CK group and the low-concentration J6 bacterial solution treatment, but the relative chlorophyll content of sunflowers in the CK group was significantly lower than that in the medium-concentration J6 bacterial solution and the high-concentration J6 bacterial solution. After adding the Burkholderia SX-J6 bacterial solution, the chlorophyll content of sunflower leaves was increased, indicating that Burkholderia SX-J6 can promote the utilization of inorganic potassium and enhance the photosynthetic capacity of plants.

[0057] Three days after the last addition of bacterial solution to each treatment group, three replicate sunflower plants in each treatment group were harvested and placed in a 105 o C oven for 2 hours; then, adjust the oven temperature to 75 o C, continue drying for 24 hours until the sample has constant weight. Take 10-15g of each of the three dried samples from each treatment group and use "nitric acid perchloric acid digestion-atomic absorption spectrometry" to determine the total potassium content in the sunflower plants. Statistical tests were performed to determine whether there were significant differences in the total potassium content of sunflowers between different experimental groups. After analyzing the data, R language (R v4.1.2) was used to draw the graph. The results are shown in Figure 2. Figure 7 shown.

[0058] according to Figure 7 It can be seen that the CK group and the low-concentration J6 bacterial solution (1.0×10 6 CFU / mL), medium concentration J6 bacterial solution (1.0×10 7 CFU / mL and high concentration J6 bacterial solution (1.0×10 8CFU / mL) were 29.45, 34.51, 32.60 and 32.54 g / kg, respectively. The potassium content of sunflower plants in the CK group was significantly lower than that in the treatments of medium concentration J6 solution, medium concentration J6 solution and high concentration J6 solution. After adding Burkholderia SX-J6 solution, the total potassium content of sunflower plants was increased, indicating that Burkholderia SX-J6 can promote the utilization of inorganic potassium by sunflower plants and improve the potassium absorption capacity of plants.

[0059] Based on the above content, it can be seen that the Burkholderia SX-J6 provided by the present invention is salt- and alkali-resistant, can effectively survive in a matrix without an organic carbon source, has carbon fixation ability, and the strain can decompose inorganic potassium in the matrix, has the ability to dissolve potassium, and can also produce high amounts of indoleacetic acid, and can improve the soil in fragile areas, especially the soil improvement in photovoltaic fields in fragile areas.

[0060] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A strain of Burkholderia Burkholderia sp. )SX-J6, the collection number is CGMCC NO.31723.

2. A bacterial agent, characterized in that The active ingredient of the bacterial agent includes the Burkholderia SX-J6 described in claim 1.

3. The bacterial agent according to claim 2, characterized in that The concentration of Burkholderia SX-J6 in the bacterial agent is 1×10 6 ~1×10 8 CFU / mL.

4. Use of the Burkholderia SX-J6 described in claim 1 or the bacterial agent described in claim 2 or 3 in improving soil in vulnerable areas and / or preparing indoleacetic acid.

5. The use according to claim 4, characterized in that: The fragile area soil includes fragile photovoltaic field area soil.

6. The use according to claim 4 or 5, characterized in that: The fragile zone soil improvement includes increasing the effective potassium content in the fragile zone soil and improving plant quality.

7. A method for preparing indoleacetic acid, characterized in that: The steps include: The Burkholderia SX-J6 described in claim 1 or the bacterial agent described in claim 2 or 3 is inoculated into a culture medium containing L-tryptophan, and fermentation is carried out to obtain a fermentation liquid; the fermentation liquid contains indoleacetic acid.

8. The preparation method according to claim 7, characterized in that: The fermentation culture temperature is 29-39° C., the rotation speed is 170-200 rpm, and the time is 36-60 hours.

9. A method for increasing the effective potassium content in soil in fragile areas, characterized in that: The Burkholderia SX-J6 described in claim 1 or the bacterial agent described in claim 2 or 3 is inoculated into the soil of the vulnerable area.

10. The method according to claim 9, characterized in that The content of mineral potassium in the soil of the fragile area is 18626.97~22744.30 μg / g, and the concentration of non-exchangeable potassium is 744.41~1072.48 μg / g.

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