CN114806931B

CN114806931B - Bacillus bailii YQ-1-8 and application thereof

Info

Publication number: CN114806931B
Application number: CN202210343295.7A
Authority: CN
Inventors: 黄亚丽; 刘银双; 赵阳阳; 李一鸣; 李清扬; 彭正萍; 韩永辉; 张晓旭; 陈晓波; 牛宏进; 何礼; 王淑霞
Original assignee: Hebei University of Science and Technology
Current assignee: Hebei University of Science and Technology
Priority date: 2022-03-31
Filing date: 2022-03-31
Publication date: 2023-07-14
Anticipated expiration: 2042-03-31
Also published as: CN114806931A

Abstract

The invention relates to the technical field of microorganisms, and particularly discloses bacillus beijerinus YQ-1-8 and application thereof. The bacillus belicus (Bacillus velezensis) YQ-1-8 has a strain preservation number of CGMCC No.24438, and can be used as a plant growth promoting and saline-alkali soil improving product. The bacillus bailii YQ-1-8 provided by the invention has remarkable saline-alkali soil improvement and plant growth promotion effects, can realize the promotion of the rapid growth of plants in the environment of facility degraded saline-alkali soil, and has important application value in the field of facility planting.

Description

Bacillus bailii YQ-1-8 and application thereof

Technical Field

The invention relates to the technical field of microorganisms, in particular to bacillus beijerinus YQ-1-8 and application thereof.

Background

Facility planting is a modern agricultural production mode for ensuring annual supply of vegetables and improving agricultural planting benefits. However, the soil in the facilities is affected by the factors such as a closed greenhouse structure, excessive fertilization, blind irrigation and the like, so that the problems of soil hardening, secondary salinization and the like often occur, and the yield and quality of crops are reduced. Therefore, improvement and repair of the degraded soil of the facility are needed to effectively guarantee sustainable development of the vegetable industry of the facility.

Through research and practical application for many years, rescue measures such as alternate stubble, salt removal by water, soil replacement, salt reduction, organic fertilizer application and the like are established for the improvement of the degraded soil of the facility vegetables, but the measures have larger production limit in the intensive planting area of the facility vegetables, are difficult to continuously improve the soil, and cannot fundamentally solve the problem that the plant growth is affected due to the degradation of the soil. Therefore, finding new strategies to reduce the damage of soil salinization to crop growth is of great importance.

The microorganism has important effects on improving the physical and chemical properties of soil and supplying plant nutrients. The microbial agent with a certain function is combined with soil improvement measures, so that the degraded soil can be improved more effectively, and the degraded soil of the facility vegetables can be repaired more effectively. The main manifestation of the facility degraded soil is that the salinization degree of the soil is increased and the plant growth is limited due to unbalanced nutrient supply, however, most microorganisms are difficult to grow in the degraded soil environment with high salinization degree, the action effect is not ideal, and the condition of the plant growth limitation cannot be effectively improved.

Disclosure of Invention

Aiming at the problems of the prior measures for improving the facility degraded soil, the invention provides bacillus bailii YQ-1-8 and application thereof, wherein the bacillus bailii YQ-1-8 has good salt resistance, can be normally propagated in the facility degraded soil with higher salinization degree, realizes good plant promotion effect in the salinization soil, and can ensure the normal growth of plants in the facility degraded soil.

In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:

bacillus bailii YQ-1-8, wherein the strain preservation number of the Bacillus bailii (Bacillus velezensis) YQ-1-8 is CGMCC No.24438. The Bacillus belicus YQ-1-8 is preserved in China general microbiological culture Collection center (China Committee for culture Collection of microorganisms) at 28 days of 2022, and has a preservation address of North Chen Xili No.1 and 3 in the Korean region of Beijing city.

Compared with the prior art, the bacillus belicus YQ-1-8 provided by the invention has the viability in a salt concentration environment with a wider range, and meanwhile, the bacillus belicus YQ-1-8 can effectively degrade organic phosphorus in soil, can generate a large amount of indole-3-acetic acid and extracellular polymer EPS, realizes the growth promotion effect on plants, and ensures that the plants grow rapidly in salinized or hardened degenerated soil. Therefore, the bacillus bailii YQ-1-8 realizes the effect of promoting plant growth in facility degenerated soil and has important application value in the field of facility planting.

The invention provides application of bacillus beijerinus YQ-1-8 as a saline-alkali soil improvement product.

The invention provides application of bacillus beijerinus YQ-1-8 as a plant growth promoting product.

The invention provides application of bacillus belicus YQ-1-8 as an organophosphorus degrading product.

The invention provides application of bacillus belicus YQ-1-8 in producing indole-3-acetic acid IAA.

The invention also provides application of the bacillus belicus YQ-1-8 in the production of extracellular polymer EPS.

The invention also provides a microbial agent, which comprises the bacillus bailii YQ-1-8.

Preferably, the microbial agent further comprises a microbial carrier.

Preferably, the microbial carrier comprises at least one of diatomite, attapulgite and sodium alginate.

The invention also provides a preparation method of the microbial agent, which comprises the following steps: activating the bacillus belicus YQ-1-8, inoculating the bacillus belicus YQ-1-8 into an LB liquid culture medium, and shaking and culturing for 20-30h at 25-28 ℃ to obtain a culture solution; then inoculating the culture solution into a fermentation culture medium, and shaking and culturing for 70-75 hours at 25-28 ℃ to obtain a fermentation solution; mixing the fermentation broth with microorganism carrier, and drying to obtain viable bacteria concentration of 2×10 ⁸ cfu/g-2×10 ⁹ cfu/g of microbial agent; the formula of each liter of the fermentation medium is as follows: 7-9g of peptone, 8-12g of glucose, 4-5g of beef extract and 0.8-1.2g of yeast powder, supplementing 1000mL of water, and regulating the pH value to 6.8-7.2.

Drawings

FIG. 1 is a graph showing growth of cucumber seeds treated with YQ-1-8 bacteria solution and cucumber seeds of a blank group in example 2 of the present invention;

FIG. 2 is a graph showing morphological characteristics of colonies of the strain YQ-1-8 in example 6 of the present invention;

FIG. 3 is a phylogenetic tree construction diagram of Bacillus bailii YQ-1-8 in example 6 of the present invention;

FIG. 4 is a graph showing the results of the organophosphorus lysis test for the strain YQ-1-8 in example 7 of the present invention;

FIG. 5 is a graph showing the IAA-producing ability test result of the strain YQ-1-8 of example 7 of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the following examples in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

The experimental methods used in the following examples are conventional in the art unless otherwise specified.

The raw materials, reagents and the like used in the following examples were obtained from commercial sources unless otherwise specified.

In the following examples:

the formula of the LB solid medium is as follows: 10g of tryptone, 5g of yeast powder, 10g of NaCl, 15g of agar, and distilled water to 1L, regulating the pH to 7.0, and sterilizing at 115 ℃ for 30min.

The formula of the LB liquid medium is as follows: 10g of tryptone, 5g of yeast powder, 10g of NaCl and distilled water to 1L, regulating the pH to 7.0, and sterilizing at 115 ℃ for 30min.

The formula of the fermentation medium is as follows: 8g of peptone, 10g of glucose, 4.5g of beef extract, 1g of yeast powder, and distilled water to 1L, regulating the pH value to 7.0, and sterilizing at 115 ℃ for 30min.

The formula of the potassium-dissolving culture medium is as follows: sucrose 5g, na ₂ HPO ₄ 2g，MgSO ₄ 0.5g，FeCl ₃ 0.005g，CaCO ₃ 0.1g, 1g of potassium feldspar powder (300 meshes), 15g of agar and distilled water to 1L, and sterilizing for 30min at 115 ℃.

The formula of the inorganic phosphorus culture medium is as follows: glucose 10g, (NH) ₄ ) ₂ SO ₄ 0.5g, yeast powder 0.5g,NaCl 0.3g,MgSO ₄ 0.3g，KCl 0.3g，FeSO ₄ 0.03g，MnSO ₄ 0.03g，Ca ₃ (PO ₄ ) ₂ 5g, 15g of agar and distilled water to 1L, and sterilizing at 115 ℃ for 30min.

The formula of the organic phosphorus culture medium is as follows: glucose 10g, (NH) ₄ ) ₂ SO ₄ 0.5g, yeast powder 0.5g,NaCl 0.3g,MgSO ₄ 0.3g，KCl 0.3g，FeSO ₄ 0.03g，MnSO ₄ 0.03g of lecithin 0.2g, caCO ₃ 1g, 15g of agar and distilled water to 1L, and sterilizing at 115 ℃ for 30min.

The formula of the IAA culture medium is as follows: k (K) ₂ HPO ₄ 1.15g, peptone 20g, glycerol 15ml, L-tryptophan 0.1g, mgSO ₄ 1.5g, distilled water is added to 1L, and the mixture is sterilized at 115 ℃ for 30min.

The siderophore medium (CAS medium) was formulated as follows: chrome azure 60.5mg, hexadecyl trimethyl ammonium bromide (HDTMA) 72.9mg, feCl ₃ 2.645g, 295.25mg of sodium dihydrogen phosphate dihydrate, 1213.5mg of sodium dihydrogen phosphate dodecahydrate, NH ₄ Cl 125mg，KH ₂ PO ₄ 37.5mg,NaCl 62.5mg agar 9g, distilled water to 1L, and sterilizing at 116℃for 30min.

The formula of the nitrogen fixation culture medium is as follows: KH (KH) ₂ PO ₄ 0.2g，MgSO ₄ 0.2g，NaCl 0.2g，CaCO ₃ 5g, mannitol 10g, caSO ₄ 0.1g, 15g of agar, distilled water to 1L, and sterilizing at 121 ℃ for 15min.

The formula of the EPS production culture medium is as follows: sucrose 20g, K ₂ HPO ₄ 0.2g，KH ₂ PO ₄ 0.5g，NaCl 100g，MgSO ₄ 0.5g, 3g of yeast powder, and distilled water to 1L, and sterilizing at 121 ℃ for 15min.

Example 1

Screening procedure for Bacillus bailii YQ-1-8

The five-point sampling method is used for collecting 32 facility soil samples which are planted for more than ten years in the Han Yongnian, the Jiufang Yongqing and the Cangzhou Qing dynasty of China. Screening of salt-tolerant microorganisms was performed using LB medium with a salt content of 10 wt%. 5g of the test soil was put into a conical flask containing 45mL of sterile water, and the mixture was shaken at 200r/min for 30min to obtain a soil mixture. Diluting the soil mixed solution according to gradient, and selecting the diluted concentration gradient to be 10 ^-4 、10 ^-5 、10 ^-6 100. Mu.L of the soil mixture was separately aspirated and applied to LB solid medium containing 10wt% NaCl for isolation of salt tolerant microorganisms3 plates per dilution. The plates are placed in a constant temperature incubator at 28 ℃ for 96 hours in an inverted mode, strains with different colony forms and larger colony diameters are picked up on the plates, and purified by streaking for 3 times, 40 strains of the strains are obtained through co-purification, the serial numbers of the strains are shown in the table 1, and the purified strains are stored in a refrigerator at-80 ℃ for later use.

Example 2

Salt-tolerant strain pro-active fruit primary screening

40 salt-tolerant strains stored at-80 ℃ in the example 1 are activated on an LB plate, and then the activated strains are inoculated into an LB liquid medium for culturing for 24 hours at 28 ℃. Centrifuging the bacterial liquid at 10000rpm for 10min, removing the supernatant, adding 10ml of sterile water for shaking, re-suspending the bacterial liquid, and re-suspending the bacterial liquid with the sterile water until the OD600 is 0.1 to obtain the bacterial liquid. The cucumber seeds are placed in the bacterial liquid with the OD600 of 0.1 for soaking for 4 hours, the cucumber seeds are placed on sterilized filter paper in order, 4mL of sterile saline water containing 1wt% of NaCl (fully soaked) is added, the cucumber seeds are placed in a 28 ℃ incubator for culturing for 72 hours, the simplified vitality index growth rate of the cucumber seeds is measured, and the growth promotion result of the strains on the cucumber is counted (the cucumber seeds which are not treated by the bacterial liquid in the same batch are used as blank control).

Simplified vigor index = (average root length + average stem length) x germination rate of seeds

Simplified vitality index increase rate = (treatment group simplified vitality index-control group simplified vitality index)/control group simplified vitality index x 100%

As shown in Table 1, the primary screening results show that 10 strains of bacteria such as 1A-3, 2A-2, YN4-2 and the like do not show growth promotion effect, and the simplified activity index increase rate of 21 strains of bacteria such as 2A-1, 2A-7, YQ-3-1 and the like is between 0 and 10 percent. The simplified activity index increasing rate of 9 strains of 3A-3, YQ-1-3, SN-1-5 and the like is more than 10%, wherein the highest simplified activity index increasing rate of YQ-1-8 strains reaches 15.18%.

TABLE 1 simplified viability index increase Rate of strains%

Strain numbering	Growth rate/%	Strain numbering	Growth rate/%	Strain numbering	Growth rate/%
						1A-3	-	YN-2-3	-	SN-1-2	10.75
2A-1	9.45	YN-2-6	2.79	SN-1-5	10.62
						2A-2	-	YN-2-2	8.36	YQ-8-3	2.79
2A-7	7.82	YN-3-6	1.33	YQ-8-4	7.96
						3A-3	11.40	YN-3-4	2.92	YQ-1-1	4.88
YQ-1-3	11.89	SN-4-2	5.04	YQ-1-4	2.66
						YQ-3-1	4.07	YN-4-3	-	YQ-1-5	13.58
SN-1-6	2.44	SN-4-4	-	YQ-8-1	10.18
						SN-13-3	5.70	SN-13-2	-	YQ-1-8	15.18
YN-4-2	-	YN-4-5	3.45	YQ3-2	10.19
						1A-2	-	SN-4-3	-	SN-4-6	8.81
YQ-3-3	2.78	YQ-1-7	-	SN-13-4	12.92
						YQ-3-4	6.07	YQ-8-2	9.51
YN-3-2	0.54	YN-3-5	2.36

The growth of cucumber seeds treated with YQ-1-8 bacterial liquid and cucumber seeds of a blank control group are shown in figure 1.

Example 3

Determination of salt tolerance of 9 strains selected in example 2 with a reduced viability index increase of greater than 10%

Activating 9 strains with growth promoting capability of more than 10% on an LB (LB) culture medium, inoculating the activated strains on an LB solid culture medium with NaCl mass concentration of 5%, 7%, 10%, 15% and 20%, culturing at constant temperature of 28 ℃ for 7d, repeating each strain for 3 times, and observing the growth condition of the strains under different salt concentration gradients. The growth is very vigorous and marked as "+++", the vigorous growth is recorded as "+++", the vigorous growth is marked as "++", growth is generally indicated as "+", and growth is inhibited as "-". As shown in Table 2, it can be seen that the YQ-1-3, YQ-8-1, YQ-3-2, SN-13-4, YQ-1-8 and 3A-3 of the 9 growth promoting strains have strong salt tolerance, wherein the YQ-1-8 strain can still grow normally in LB medium with the salt content reaching 20%.

TABLE 2 growth of growth-promoting bacteria at different salt concentrations

Strain numbering	5％	7％	10％	15％	20％
						YQ-1-3	+++	++	++	+	-
YQ-1-5	++	++	+	-	-
						YQ-1-8	++	++	++	++	++
YQ-8-1	+++	++	++	+	-
						YQ-3-2	++	++	++	+	-
SN-1-2	++++	++++	++	-	-
						SN-1-5	++++	++++	++	-	-
SN-13-4	++++	++++	++	+	-
						3A-3	++	++	++	+	-

Example 4

Selecting bacterial strains 3A-3 and YQ-1-8 with good growth promoting effect and good salt tolerance, and measuring the soil colonization capacity

Activating YQ-1-8 strain, inoculating into LB liquid culture medium, and shake culturing at 26 deg.C for 24 hr to obtain culture solution; then inoculating the culture solution into a fermentation culture medium, and shaking and culturing for 72 hours at 26 ℃ to obtain a fermentation solution; mixing the fermentation broth with diatomite, and spray drying to obtain a viable bacteria concentration of 1×10 ⁹ cfu/g microbial agent.

The microbial agent containing the 3A-3 strain is obtained by the same method.

Determination of the colonization of the soil by the 3A-3 and YQ-1-8 strains by means of potting experiments. Cucumber was selected as a cultivated crop and experiments were carried out in a flowerpot having a diameter of about 7cm and a height of 7 cm. The microbial agents were mixed with sterilized soil (the concentration of viable bacteria in the soil after mixing is shown in Table 3), and then the viable bacteria count of the 3A-3 strain and YQ-1-8 strain in the soil was measured at 1d, 3d, 5d, 7d, 14d, 28d, 60d after inoculation, respectively, and the results are shown in Table 3, and it can be seen that the YQ-1-8 strain has a strong colonization ability and the number in the soil of 1, 3, 5, 7, 14, 28, 60d is less variable. The strain YQ-1-8 has good soil colonization ability, and the number of the strain YQ-1-8 in the soil after 60 days of inoculation is 2.19X10 ⁷ cfu/g, can be used as a microbial preparation or fertilizer for application on crops.

TABLE 3 colonization of strains in soil

Inoculation time (d)	Strain YQ-1-8 (. Times.10) ⁷ cfu/g)	Strain 3A-3 (. Times.10) ⁷ cfu/g)
			1	2.61	16.53
3	2.06	10.12
			5	0.94	6.20
7	1.46	2.44
			14	1.53	0.89
28	1.68	0.90
			60	2.19	0.85

Example 5

Salt-tolerant growth-promoting strain YQ-1-8 for promoting growth of cucumber

Activating strain YQ-1-8 on LB solid medium by streaking, culturing at 28deg.C for 48 hr, inoculating thallus to 100mL sterilized LB liquid medium, culturing at 28deg.C under shaking table condition of 200rpm/min for 12 hr, centrifuging bacterial liquid at 10000rpm for 10min, removing supernatant, adding 10mL sterile water, shaking, suspending thallus, re-suspending thallus with sterile water, and regulating OD ₆₀₀ 0.1 to obtain a bacterial liquid.

The preparation method of the bacterial liquid of the 3A-3 strain is the same as that described above.

The method comprises the steps of adopting a potting test, adjusting the soil to be facility vegetable planting soil, adjusting the total salt content of the soil to be 0.5%, adding the soil into a flowerpot with the diameter of 7cm and the height of 7cm for test, and adjusting the soil and the concentration to be OD ₆₀₀ Mixing 0.1 bacterial liquid (10 kg soil: 1L bacterial liquid), treating with equal amount of sterile water as control group, planting cleaned cucumber seeds with uniform size in flowerpot, 3 seeds per pot, retaining seedling with uniform growth vigor after cucumber germinates, retaining 1 seedling per pot, culturing for 4 weeks, measuring cucumber stem thickness, plant height, fresh quality on ground and drynessQuality, chlorophyll content. As shown in Table 4, YQ-1-8 was able to more significantly promote the growth of cucumber in saline soil than 3A-3 strain.

TABLE 4 influence of strains on cucumber seedling growth

Note that: data are expressed as mean ± Standard Deviation (SD), different lowercase letters indicating p <0.05 level differences.

Example 6

Identification of Strain YQ-1-8

Morphological identification:

the strain YQ-1-8 is taken out from the low temperature refrigerator and inoculated on LB solid medium, and is cultured for 48 hours in a 28 ℃ incubator, and the growth condition and morphological characteristics of the bacterial colony are observed as shown in figure 2: the strain grows faster, is oval, white, opaque, convex and wrinkled at the edge.

Molecular biology identification:

the strain with the strain number YQ-1-8 is inoculated into LB culture medium, shake-cultured for 24 hours at 28 ℃, the genome DNA of the strain is extracted by adopting a Tiangen biochemical technology (Beijing) limited company genome DNA extraction kit, and then PCR amplification is carried out by using the extracted total DNA as a template and a primer pair of 27f (5'-AGAGTTTGATCCTGGCTCAG-3', SEQ ID NO. 1) and 1492r (5'-TACGGCTACCTTGTTACGACTT-3', SEQ ID NO. 2). The PCR reaction system is 25 mu L, and the reaction system is: 1. Mu.L of genomic DNA, 2.5. Mu.L of 10 XPCR buffer, 0.5. Mu.L of 27f primer, 0.5. Mu.L of 1492r primer, 2. Mu.L of dNTPs, 0.5. Mu.L of Taq enzyme (5U/. Mu.L), ddH ₂ O makes up 25. Mu.L. The reaction conditions are as follows: pre-denaturation at 94℃for 5min; denaturation at 94℃for 1min, annealing at 50℃for 1min, extension at 72℃for 2min, and cycling for 35 times; extending at 72℃for 10min. The PCR product was detected by electrophoresis on a 1% agarose gel, and the PCR product with a PCR band size of about 1500bp was sequenced by Shanghai Biotechnology Co., ltd. To obtain a 16S rDNA sequence (shown as SEQ ID NO. 3).

The NCBI website (www.ncbi.nlm.nih.gov) is logged in to carry out homology comparison analysis on the obtained 16S rDNA gene sequence and sequences known in GenBank, sequences with similar homology are selected for systematic evolution analysis, multiple comparison is carried out on the sequences, then a phylogenetic tree is constructed by adopting a neighbor-Joining method (MEGA 7 software), and the phylogenetic position of the strain is finally determined as shown in FIG. 3. Sequence analysis shows that the strain belongs to bacillus beijerinus (Bacillus velezensis). The Bacillus bailii YQ-1-8 is preserved in China general microbiological culture Collection center (CGMCC) at 28 days of 2.2022, and has a preservation number of CGMCC No.24438 and a preservation address of North Chen Xilway No.1 and 3 in the Korean region of Beijing city.

Example 7

Growth-promoting mechanical analysis of strain YQ-1-8:

and (3) streaking the strain YQ-1-8 obtained by primary screening on an LB solid medium, and culturing for 2 days in an inverted incubator at the temperature of 28 ℃ for later use. And inoculating the activated strain into 50mL of LB liquid medium, and performing shake culture at 28 ℃ for 24 hours to obtain bacterial liquid required by a test. The bacterial liquid 5. Mu.L was inoculated onto a plate of prepared potassium-decomposing medium, inorganic phosphorus medium, organic phosphorus medium, siderophore medium, nitrogen fixation medium, and cultured at 28℃for 7d, and the test results were observed and recorded as shown in Table 5. The strain grows on an organophosphorus medium and turbidity spots appear around the strain, and the strain has the capacity of degrading organophosphorus in soil as shown in fig. 4.

In addition, inoculating the bacterial liquid into IAA culture medium at 5% inoculum size, shake culturing at 28deg.C for 48 hr, centrifuging at 10000 Xg for 10min, collecting 1ml supernatant, and adding 2ml Salkowski reagent (concentrated sulfuric acid 15ml, double distilled water 25ml,0.5mol/l FeCl) ₃ 0.75 ml) was mixed and was darkened for 30 minutes, and the IAA medium was observed to turn pink in color, as shown in FIG. 5, indicating that the strain had IAA-producing ability. In addition, the strain is inoculated in EPS culture medium according to 5 percent of inoculum size, shake cultivation is carried out for 48 hours at 28 ℃,10 ml of culture solution is taken for 10000r/min and centrifuged for 10min, the supernatant is removed, and the thalli are dried and weighed; meanwhile, adding 30mL of 95% ethanol into the supernatant for alcohol precipitation, standing at 4 ℃ in a refrigerator overnight, centrifuging the mixed solution at 10000r/min for 10min, removing the supernatant, drying and weighing the precipitate, wherein the ratio of EPS dry weight to thallus dry weight isAs a result of measurement, it was shown that the strain was capable of producing extracellular polymer in an amount of 0.467g/g, as an EPS yield of the strain.

TABLE 5 results of growth-promoting physiological analysis of Strain YQ-1-8

The type of growth promoting mechanism	Fruit of promoting effect
		Potassium decomposing process	-
Inorganic phosphorus decomposition	-
		De-organic phosphorus	+
IAA production	+
		Iron production carrier	-
Nitrogen fixation	-
		EPS production	+(0.467g/g)

Note that: "+": has this function; "-": without this function.

Example 8

Bacillus bailii YQ-1-8 microbial inoculum for improving salinized soil

Compounding Bacillus bailii YQ-1-8 with attapulgite to obtain microbial preparation with effective bacterial count of 2 hundred million (activating Bacillus bailii YQ-1-8, inoculating into LB liquid culture medium, shaking culture at 26deg.C for 24 hr to obtain culture solution, inoculating into fermentation culture medium, shaking culture at 26deg.C for 72 hr to obtain fermentation solution, mixing the fermentation solution with attapulgite, and drying to obtain active bacterial concentration of 2×10 ⁸ cfu/g microbial agent), and performing a soil improvement test. The test is carried out by taking cucumber as a test crop, carrying out the test in a greenhouse which is planted for more than 10 years, applying YQ-1-8 microbial inoculum before soil preparation, applying the YQ-1-8 microbial inoculum to the greenhouse, and repeating each treatment for 3 times and randomly arranging the treatments, wherein the conventional management and the application of YQ-1-8 microbial inoculum and the attapulgite (control group) are adopted. And (3) detecting the soil salinity improvement index of the saline-alkali soil 30 days after cucumber transplanting, measuring the total salt content of the soil by adopting a leaching solution drying method, measuring the conductivity of the soil by adopting a conductivity meter, and measuring the yield of the cucumber in the harvesting period. As shown in Table 6, the salt content of the soil can be reduced by 11.39%, the conductivity can be reduced by 16.38%, and the yield can be improved by 11.91% by applying Bacillus belicus YQ-1-8 microbial inoculum. The YQ-1-8 microorganism has better effects of reducing the salt content of soil and improving the crop yield.

TABLE 6 influence of YQ-1-8 microbial inoculum on soil salinity and yield

Treatment of	Total salt content (g/kg)	Conductivity (mu S/cm)	Yield (kg/mu)
				Conventional management	8.95	460.2	7424
YQ-1-8	7.93	384.8	8308
				Attapulgite	8.12	440.3	7942

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, or alternatives falling within the spirit and principles of the invention.

SEQUENCE LISTING

<110> university of Hebei technology

<120> Bacillus bailii YQ-1-8 and application thereof

<130> 2022

<160> 3

<170> PatentIn version 3.5

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ctacgtgcca gcagccgcgg taatacgtag gtggcaagcg ttgtccggaa ttattgggcg 540

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cttgacatcc tctgacaatc ctagagatag gacgtcccct tcgggggcag agtgacaggt 1020

ggtgcatggt tgtcgtcagc tcgtgtcgtg agatgttggg ttaagtcccg caacgagcgc 1080

aacccttgat cttagttgcc agcattcagt tgggcactct aaggtgactg ccggtgacaa 1140

accggaggaa ggtggggatg acgtcaaatc atcatgcccc ttatgacctg ggctacacac 1200

gtgctacaat ggacagaaca aagggcagcg aaaccgcgag gttaagccaa tcccacaaat 1260

ctgttctcag ttcggatcgc agtctgcaac tcgactgcgt gaagctggaa tcgctagtaa 1320

tcgcggatca gcatgccgcg gtgaatacgt tcccgggcct tgtacacacc gcccgtcaca 1380

ccacgagagt ttgtaacacc cgaagtcggt gaggtaacct tttaggagcc agccgccgaa 1440

ggtacaga 1448

Claims

1. A bacillus bailii YQ-1-8 strain is characterized in that: the strain preservation number of the bacillus belicus (Bacillus velezensis) YQ-1-8 is CGMCC No.24438.

2. Use of bacillus belgium YQ-1-8 according to claim 1 as a saline-alkali soil improvement product.

3. Use of bacillus belgium YQ-1-8 according to claim 1 as a plant growth promoting product.

4. Use of bacillus belgium YQ-1-8 according to claim 1 as a product for degrading organic phosphorus.

5. Use of bacillus belgium YQ-1-8 according to claim 1 for the production of indole-3-acetic acid IAA.

6. Use of bacillus belgium YQ-1-8 according to claim 1 for the production of extracellular polymeric EPS.

7. A microbial agent is characterized in that: comprising Bacillus belicus YQ-1-8 as claimed in claim 1.

8. The microbial agent of claim 7, wherein: also included are microbial carriers.

9. The microbial agent of claim 8, wherein: the microbial carrier comprises at least one of diatomite, attapulgite and sodium alginate.

10. The method for preparing the microbial agent according to any one of claims 7 to 9, characterized in that: comprising the following steps: activating the bacillus belicus YQ-1-8, inoculating the bacillus belicus YQ-1-8 into an LB liquid culture medium, and shaking and culturing for 20-30h at 25-28 ℃ to obtain a culture solution; then inoculating the culture solution into a fermentation culture medium, and shaking and culturing for 70-75 hours at 25-28 ℃ to obtain a fermentation solution; mixing the fermentation broth with microorganism carrier, and drying to obtain viable bacteria concentration of 2×10 ⁸ cfu/g-2×10 ⁹ cfu/g of microbial agent; the formula of each liter of the fermentation medium is as follows: 7-9g of peptone, 8-12g of glucose, 4-5g of beef extract and 0.8-1.2g of yeast powder, supplementing 1000mL of water, and regulating the pH value to 6.8-7.2.