Disclosure of Invention
Therefore, the invention provides a preparation method and application of a streptomyces copromogenes BWL-H1 microbial inoculum, which are used for solving the problems.
The technical scheme of the invention is realized as follows: a preparation method of a streptomyces copromogenes BWL-H1 microbial inoculum comprises the following steps:
s1, solid fermentation of streptomyces coprostanus BWL-H1: taking wormcast and wheat bran as substrates, inoculating streptomyces copromosus BWL-H1 on the substrates, fermenting for 4-10 days at 25-30 ℃, drying for 20-30H at constant temperature of 30-40 ℃, crushing and sieving with a 100-300-mesh sieve for later use to obtain spore powder;
s2, preparing wettable powder: mixing the spore powder with a wetting agent, a dispersing suspending agent and a carrier to prepare wettable powder, namely the streptomyces copromogenes BWL-H1 microbial inoculum, wherein the wettable powder comprises the following raw materials in percentage by mass: 8-12% of spore powder, 3-8% of wetting agent, 3-8% of dispersing suspending agent and the balance of carrier.
Further, the mass ratio of the wormcast to the wheat bran in the S1 is 2-5: 1.
Further, the wettable powder in the S2 comprises the following raw materials in percentage by mass: 10% of spore powder, 5% of wetting agent, 5% of dispersing and suspending agent and the balance of carrier.
Further, the wetting agent is one of sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, nekal BX and AB-3, and the mass concentration is 1-5%.
Further, the dispersing suspending agent is sodium methylene dinaphthalene sulfonate (NNO) or sodium lignin sulfonate, and the mass concentration is 1-5%.
Further, the carrier is one of diatomite, kaolin and white carbon black.
Further, the prepared streptomyces copromosus BWL-H1 microbial inoculum is applied as the control effect of cucumber fusarium wilt.
Compared with the prior art, the invention has the beneficial effects that:
the streptomyces copromogenes BWL-H1 strain separated from soil at the earlier stage of the invention has the advantages of rapid growth and reproduction, rich sporulation, strong stress resistance and stable genetic character. The invention selects wheat bran and wormcast to carry out solid fermentation on the wheat bran and wormcast so as to produce bacterial powder, and the spore content can reach 9.6 multiplied by 109CFU/g, then screening out carriers and auxiliary agents suitable for the streptomyces coproagula BWL-H1 through biocompatibility determination and a national standard method, namely carrier white carbon black, wetting agent sodium dodecyl benzene sulfonate and dispersing agent NNO, preparing wettable powder according to the steps that 10% of streptomyces coproagula BWL-H1 spore powder, 5% of wetting agent sodium dodecyl benzene sulfonate, dispersing agent NNO 5% and the balance of carrier white carbon black are supplemented to 100%, and the wettable powder has a high prevention effect on cucumber fusarium wilt.
The streptomyces copromogenes BWL-H1 is prepared into the microbial inoculum, so that the growth of pathogenic microorganisms is inhibited, the occurrence of diseases is reduced, the use of chemical fertilizers and pesticides is reduced, and the theoretical basis is laid for further popularization and application.
Detailed Description
In order to better understand the technical content of the invention, specific examples are provided below to further illustrate the invention.
The experimental methods used in the examples of the present invention are all conventional methods unless otherwise specified.
The materials, reagents and the like used in the examples of the present invention can be obtained commercially without specific description.
The streptomycete strain of the invention: streptomyces faecalis BWL-H1 is separated from soil under litchi trees in the mountain of Bawang Ling of Changjiang county, Hainan province and stored in research center of green agricultural biological preparation creation engineering in Hainan province.
The cucumber fusarium wilt of the invention is as follows: fusarium GF, isolated from diseased cucumber species of Sichuan academy of agricultural sciences, was maintained in the research center for the creation of green agricultural biologicals in Hainan province.
Example 1
A preparation method of a streptomyces copromogenes BWL-H1 microbial inoculum comprises the following steps:
s1, solid fermentation of streptomyces coprostanus BWL-H1: taking wormcast and wheat bran as a substrate, wherein the mass ratio of wormcast to wheat bran is 2:1, inoculating streptomyces copromogenes BWL-H1 on the substrate, fermenting for 4 days at 25 ℃, drying for 20 hours at constant temperature of 30 ℃, crushing and sieving with a 100-mesh sieve for later use to obtain spore powder;
s2, preparing wettable powder: 8 percent of spore powder, 3 percent of sodium dodecyl benzene sulfonate, 3 percent of methylene dinaphthalene sodium sulfonate and 86 percent of white carbon black are mixed according to the mass percentage to prepare wettable powder, namely the streptomyces coproagulans BWL-H1 microbial inoculum.
Example 2
A preparation method of a streptomyces copromogenes BWL-H1 microbial inoculum comprises the following steps:
s1, solid fermentation of streptomyces coprostanus BWL-H1: taking wormcast and wheat bran as a matrix, wherein the mass ratio of wormcast to wheat bran is 5:1, inoculating streptomyces copromogenes BWL-H1 on the matrix, fermenting at 30 ℃ for 10 days, drying at 40 ℃ for 30 hours, crushing, and sieving with a 300-mesh sieve for later use to obtain spore powder;
s2, preparing wettable powder: 12% of spore powder, 8% of sodium dodecyl benzene sulfonate, 8% of sodium methylene dinaphthalene sulfonate and 72% of white carbon black by mass percentage are mixed to prepare wettable powder, namely the streptomyces coprostanus BWL-H1 microbial inoculum.
Example 3
A preparation method of a streptomyces copromogenes BWL-H1 microbial inoculum comprises the following steps:
s1, solid fermentation of streptomyces coprostanus BWL-H1: taking wormcast and wheat bran as a matrix, wherein the mass ratio of wormcast to wheat bran is 3:1, inoculating streptomyces copromogenes BWL-H1 on the matrix, fermenting at 27 ℃ for 7 days, drying at the constant temperature of 30-40 ℃ for 24 hours, crushing, and sieving with a 200-mesh sieve for later use to obtain spore powder;
s2, preparing wettable powder: 10 percent of spore powder, 5 percent of sodium dodecyl benzene sulfonate, 5 percent of methylene dinaphthalene sodium sulfonate and 80 percent of white carbon black are mixed according to the mass percentage to prepare wettable powder, namely the streptomyces coproagulans BWL-H1 microbial inoculum.
Example 4
This example differs from the fact 3 in that the support is diatomaceous earth and the process conditions for the remaining steps are unchanged.
Example 5
This example differs from the fact 3 in that the support is kaolin and the process conditions for the remaining steps are unchanged.
Example 6
This example differs from the fact 3 in that the wetting agent is sodium lauryl sulfate and the process conditions for the remaining steps are unchanged.
Example 7
This example differs from the fact 3 in that the wetting agent is nekal BX, the process conditions for the remaining steps being unchanged.
Example 8
This example differs from the fact 3 in that the dispersing and suspending agent is sodium lignosulfonate and the process conditions for the remaining steps are unchanged.
Comparative example 1
Streptomyces faecalis BWL-H1 is prepared into Streptomyces faecalis BWL-H1 microspheres according to the Chinese plant Pathology society, research methods of research on biocontrol actinomycete spore sustained-release microspheres, Zhangwei, Fenghao et al.
First, verification experiment
(1) Spore content determination
The spore powder prepared by fermentation of examples 1-3 was measured for spore content, and the results are shown in table 1 below:
it can be seen that the spore content of example 3 can reach 9.6X 109CFU/g, indicates that fermentation at a specific temperature and time can produce a larger amount of spores.
(2) Screening of vectors
Adding the diatomite, the kaolin and the white carbon black into PDA according to the concentration of 500 mu g/ml, sterilizing at the high temperature of 121 ℃ for 20min, and then pouring the product into a flat plate for natural cooling for later use.
Culturing Streptomyces faecalis BWL-H1 for 7 days, adding 2ml of sterile water into the culture dish, slowly scraping and washing with a sterile glass slide, sucking a small amount of the sterile water on a blood counting chamber with a pipette, taking the sterile glass slide under a microscope for counting, and diluting the stock solution on a superclean bench by corresponding times to obtain the spore with the concentration of 103CFU/mL spore suspension, using a pipette gun to add 100. mu.L to PDA plate, using a sterile plate coater to spread the suspension evenly, culturing at 28 ℃ for 5 days, counting the colony number, the results are shown in Table 2 below.
TABLE 2 influence of different vectors on the colony growth of Streptomyces coproagulans BWL-H1
The results of the study showed no significant difference between the three vectors and ck. However, silica and diatomaceous earth showed stronger colony formation promoting effects compared to kaolin (table 2, fig. 1). In the research, the white carbon black has higher fineness and better suspension performance on the product, so in comparison of examples 3-5, the white carbon black in example 3 is more suitable to be used as a carrier of a streptomyces coprostanus BWL-H1 solid preparation.
(2) Screening of wetting Agents
Based on 2.5g, spore powder accounts for 10%, and the content of humectant is 1%, 3%, and 5%, and white carbon black is added to 100%. In a 250mL beaker, 100mL of standard hard water was added and the water bath was heated to 25 ℃. Weighing 2.5g of uniform sample, pouring all the sample into a beaker once on the premise of keeping the liquid level as stable as possible, starting timing at the same time, and recording the time for completely wetting. This was repeated three times, and the average was taken as the wetting time, and the wetting times of the three humectants at different concentrations are shown in Table 3.
TABLE 3 wetting characteristics of wetting agents and Effect on colony growth of Streptomyces coproagulans BWL-H1
As can be seen from the above table, SDS has better wettability, can reach 3.83 s at 5% concentration, but because it has a great influence on spore germination of actinomycetes, has poor biocompatibility with the strain, and completely inhibits spore germination at the concentration, SDBS is selected as a wetting agent, and the wetting time can be made to be less than 2min by adding the wetting agent.
(3) Screening of Dispersion suspensions
Referring to GB/T14825-2006, the suspension rates of two dispersing suspending agents, namely sodium methylenedinaphthalenesulfonate (NNO) in example 3 and sodium lignosulfonate in example 8 are compared, and when 2.5g is taken as a base number, spore powder accounts for 10%, the optimal wetting agent accounts for 5%, and when the content of the dispersing agent is respectively 1%, 3% and 5%, white carbon black is used for supplementing to 100%. Weighing a proper amount of sample, taking a 250mL beaker, adding 50mL of standard hard water, heating in a constant-temperature water bath to 30 +/-1 ℃, and adding the sample. Shaking the beaker by hand, continuing for 2min at a relatively gentle shaking rate, standing for 4min, pouring all the liquid into a 250mL measuring cylinder, and washing for multiple times until the scale is full. And (3) completely blocking the opening of the measuring cylinder by using a cover, shaking up and down for a period of time, and then continuously standing in the water bath kettle, wherein the spore concentration is measured to be C1. After standing for a sufficient period of time, the supernatant was aspirated without aspiration of the pellet, at which time the spore concentration in both barrels was measured to be C2. The suspension ratio is calculated as follows:
the suspension characteristics of the two dispersion suspending agents are shown in table 4,
TABLE 4 suspension characteristics of the Dispersion suspending agent and Effect on the growth of colonies of Streptomyces coproagulans BWL-H1
As can be seen from the above table, when no dispersant is added and only the spore powder is mixed into the silica carrier in an amount of 10%, the suspension rate of the preparation is only 42.25%. The suspension characteristic of the dispersant NNO is superior to that of sodium lignosulphonate, and the suspension rate of the preparation can reach 70.97%. Compared with the biocompatibility of the streptomyces copromogenes BWL-H1, NNO has no inhibition phenomenon on the spore germination of actinomycetes, so the NNO is selected as a dispersant to be added into the wettable powder.
Second, experiment of potted plant for preventing and treating cucumber fusarium wilt
Inoculating fusarium GF into a PDB flat plate, carrying out shake culture in a constant-temperature incubator at 28 ℃ for 7d, filtering hyphae through 2 layers of coarse gauze, and preparing into bacterial suspension with the spore concentration of 1 × 106CFU/mL for later use.
After accelerating germination, the cucumber seeds are sowed in a seedling tray, and are transplanted into a pot with the caliber of 10cm and the height of 9.5 after two weeks. The experiment was set up with 10 treatments: t1, clear water control; t2: diluting the streptomyces copromogenes BWL-H1 wettable powder of embodiment 3 by 100 times, and irrigating roots of cucumber seedlings by 100mL of spore suspension of fusarium GF after one week; t3, mixing the streptomyces copromogenes BWL-H1 microspheres and nutrient soil in a mass ratio of 1: 100, and repeating for 3 times each treatment, wherein 10 seedlings are repeated each time. After 10 days, the disease condition of the plants is investigated, and the prevention and treatment effect and the disease index standard are shown in Table 5.
TABLE 5 grading Standard and formula for diseases of different grades
The mean and standard deviation of the samples were calculated using AVERAGE and STDEVP functions in Excel2007, and multiple comparisons (P <0.05) were performed using waller-duncan in SPSS17.0 software as shown in table 6 below.
TABLE 6 preventive effect of two preparations of Streptomyces BWL-H1 on cucumber fusarium wilt
Note: t1, T2 and T3 represent control, wettable powder treatment and microsphere treatment respectively.
As can be seen from the above table, the wettable powder treatment, the microsphere treatment and the control have significant differences (P <0.05), and the control effect of the streptomyces coproanus BWL-H1 wettable powder on cucumber fusarium wilt is most obvious, can reach 48.65 percent and is significantly higher than the control effect of the streptomyces coproanus BWL-H1 microspheres on fusarium wilt.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.