Novel straw decomposition agent

Abstract

The invention belongs to the technical field of straw decomposition agents, and particularly relates to a novel straw decomposition agent. The invention relates to a novel straw decomposition agent. The novel straw decomposition agent is prepared by mixing brevibacillus laterosporus and bacillus velezensis, wherein the brevibacillus laterosporus is a brevibacillus laterosporus A60 suspending agent with the concentration of 0.5 billion cfu / mL; the bacillus velezensis is a bacillus velezensis CGMCC (China General Microbiological Culture Collection Center) No.14384 water dispersible granule of which the living spores are 20 billion per gram. When brevibacillus laterosporus A60 and bacillus velezensis CGMCC No.14384 are mixed according to the mass ratio of (1-19): (19-1) to ferment and decompose corn straw, the EC50 value of the fermented and decomposed liquid to tomato bacterial wilt ralstonia solanacearum is lower than that of any one of the fermented and decomposed liquid which is independently used, so that the decomposing agent has a synergistic effect in the aspect of inhibiting soil-borne bacterial diseases; the improvement of the prevention and treatment effect on soil-borne bacterial diseases is facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical field of straw decomposing agents, and particularly relates to a novel straw decomposing agent. Background Art

[0002] Tomato bacterial wilt is a plant soil-borne disease caused by Ralstonia solanacearum, which has greatly restricted the development of the tomato industry. Currently, the prevention and control measures mainly include disease-resistant breeding, using chemical agents, and biological control, etc. However, due to the complex genetic diversity of Ralstonia solanacearum, it is difficult to solve practical problems by implementing disease-resistant breeding without understanding its genetic characteristics; while frequent use of chemical agents easily leads to the generation of drug resistance in Ralstonia solanacearum, resulting in reduced drug efficacy and environmental pollution. Biological control uses microorganisms harmless or beneficial to plants or antagonistic microorganisms and their metabolites to inhibit the hatching of nematode eggs and reduce the viability of larvae, induce plant resistance and promote growth, so as to achieve the purpose of disease control, and has the advantages of pollution-free, low cost and not easy to produce drug resistance, and has received more and more attention in recent years.

[0003] The inventor has found through a large number of experiments that when Brevibacillus laterosporus and Bacillus velezensis are used in combination, their fermentation broth can produce a synergistic effect on Ralstonia solanacearum of tomato bacterial wilt, and can improve the control effect on soil-borne bacterial diseases. There has been no relevant report in this regard so far.

[0004] The information disclosed in this background art section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as an admission or any form of implication that this information constitutes the prior art already known to those of ordinary skill in the art. Summary of the Invention

[0005] The purpose of the present invention is to provide a novel straw decomposing agent, which has a synergistic effect in inhibiting soil-borne bacterial diseases and helps to improve the control effect on soil-borne bacterial diseases.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A novel straw decomposing agent, which is composed of Brevibacillus laterosporus and Bacillus velezensis; wherein, the Brevibacillus laterosporus is a Brevibacillus laterosporus A60 suspension agent with 500 million cfu / mL; the Bacillus velezensis is a Bacillus velezensis CGMCC No. 14384 water dispersible granule with 20 billion viable spores / gram.

[0008] More specifically, the mass ratio of Brevibacillus laterosporus to Bacillus velezensis is 1-19:19-1.

[0009] More specifically, the mass ratio of Brevibacillus laterosporus and Bacillus velezensis is 1:9.

[0010] The present invention also provides the application of the novel straw decomposing agent in preventing and controlling soil-borne bacterial diseases.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] When the present invention mixes and ferments and decomposes corn straw with Brevibacillus laterosporus A60 and Bacillus velezensis CGMCC No. 14384 in a mass ratio of 1-19:19-1, the fermentation and decomposition liquid has an EC value for Ralstonia solanacearum of tomato bacterial wilt lower than that of using any one of them alone. Especially when the mass ratio of the two is 1:9, the EC value for Ralstonia solanacearum of tomato bacterial wilt is the lowest, and is significantly lower than that of using Brevibacillus laterosporus A60 and Bacillus velezensis CGMCC No. 14384 alone. This shows that the decomposing agent of the present invention has a synergistic effect in inhibiting soil-borne bacterial diseases, which helps to improve the control effect on soil-borne bacterial diseases. 50 value is lower than that of using any one alone. Especially when the mass ratio of the two is 1:9, the EC 50 value is the lowest, and is significantly lower than that of using Brevibacillus laterosporus A60 and Bacillus velezensis CGMCC No. 14384 alone. This shows that the decomposing agent of the present invention has a synergistic effect in inhibiting soil-borne bacterial diseases, which helps to improve the control effect on soil-borne bacterial diseases. Specific embodiments

[0013] The technical solutions of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments.

[0014] 1. Inhibitory effect of different straw decomposing agents on soil-borne bacterial diseases

[0015] 1.1 Tested biocontrol bacteria

[0016] A 500 million cfu / mL suspension of Brevibacillus laterosporus A60 (Shaanxi Thompson Biotechnology Co., Ltd., registration number: PD20190035)

[0017] A 20 billion viable spores / gram water dispersible granule of Bacillus velezensis CGMCC No. 14384 (Sichuan Baishi Dongwang Biotechnology Co., Ltd., registration number: PD20211360)

[0018] 1.2 Preparation of straw fermentation and decomposition liquid

[0019] The corn straw was crushed to 4.5-6 cm, the carbon-nitrogen ratio of the material was adjusted to 25:1 with chicken manure, the water content of the material was adjusted to 60%, and the decomposing agent was inoculated at a mass ratio of 1% (the formula of the decomposing agent is shown in Table 1 below). The mixture was stirred evenly and fermented at room temperature and sealed for 35 days, and the material was turned over every 2 days during this period. The fermented and decomposed material was mixed evenly with water at a mass ratio of 1:8, sealed for 7 days, filtered with a 0.5 μm filter membrane, and the filtrate was collected to obtain the straw fermentation and decomposition liquid, which was stored at 4°C for standby.

[0020] The straw fermentation and decomposition liquid (calculated as 100% by mass) was diluted with water into 5 mass concentration gradients to determine the inhibitory effects of the straw fermentation and decomposition liquids of different straw decomposing agents on soil-borne bacterial diseases.

[0021] 1.3 Test pathogens

[0022] Ralstonia solanacearum causing tomato bacterial wilt, isolated from the rhizosphere soil of diseased tomato plants in the tomato experimental field of Guangxi Academy of Agricultural Sciences.

[0023] 1.4 Culture media

[0024] NA medium: 5 g of peptone, 10 g of glucose, 3 g of beef extract, 0.5 g of yeast extract, 20 g of agar, adjusted to pH 7.2, made up to 1 L with distilled water, autoclaved at 115 °C for 30 min.

[0025] NB medium: 5 g of peptone, 10 g of glucose, 3 g of beef extract, 0.5 g of yeast extract, adjusted to pH 7.2, made up to 1 L with distilled water, autoclaved at 115 °C for 30 min.

[0026] 1.5 Test methods

[0027] The Oxford cup method was adopted. The test pathogens were inoculated into NB liquid medium and cultured with shaking at 28 °C and 180 rpm until the logarithmic growth phase, and then diluted into a bacterial suspension of 1.0×10 8 cfu / mL. Pour 10 mL of NA medium cooled to about 50 °C into a petri dish with a diameter of 9 cm, shake well and cool to make a plate. Take 50 μL of the bacterial suspension and spread it evenly on the NA plate. Place the Oxford cup in the center of the petri dish containing the bacterial medium, add 200 μL of the diluted straw fermentation and decomposition liquid into the Oxford cup, and use the treatment with the addition of the same amount of water as the blank control. Each treatment was repeated 5 times. Place it in a bacterial incubator at 28 °C for culture, observe and record the growth of the pathogens. After 24 h, measure the diameter of the inhibition zone by the cross method, calculate its average value, and calculate the colony growth inhibition rate.

[0028]

[0029] 1.6 Data analysis

[0030] Taking the logarithm value of the straw fermentation and decomposition liquid dilution concentration as x and the probit value of the colony growth inhibition rate as y, regression analysis was carried out to calculate the EC 50 value, and the results are shown in Table 1.

[0031] Table 1 Inhibitory effects of different straw decomposing agents on Ralstonia solanacearum

[0032] Different formulations of composting agents Regression equation Correlation coefficient r <![CDATA[EC 50 (mg / L)]]> Brevibacillus brevis A60 suspension (A) with 500 million cfu / mL y = 0.7299x + 3.1778 0.9747 313.7201 Bacillus velezensis CGMCC No.14384 water dispersible granule (B) with 20 billion viable spores / gram y = 1.3307x + 2.1897 0.9547 129.3806 A + B (mixed in a mass ratio of 1:29) y = 0.2841x + 4.3497 0.9477 194.5372 A + B (mixed in a mass ratio of 1:19) y = 1.0953x + 2.9566 0.9644 73.3885 A + B (mixed in a mass ratio of 1:9) y = 0.1196x + 4.8688 0.9583 12.4982 A + B (mixed in a mass ratio of 1:1) y = 3.1401x + 0.4073 0.9825 29.0123 A + B (mixed in a mass ratio of 9:1) y = 2.3248x + 0.9275 0.9617 56.4615 A + B (mixed in a mass ratio of 19:1) y = 0.5761x + 3.8704 0.9532 91.3765 A + B (mixed in a mass ratio of 29:1) y = 1.4595x + 1.7981 0.9446 156.2593

[0033] As can be seen from Table 1, the fermentation and decomposition liquids of different straw decomposing agents have different inhibitory effects on Ralstonia solanacearum, the causative agent of tomato bacterial wilt. Among them, the fermentation and decomposition liquids of Brevibacillus laterosporus A60 and Bacillus velezensis CGMCC No. 14384 used alone had EC 50 values of 313.7201 mg / L and 129.3806 mg / L, respectively, against Ralstonia solanacearum. When the two were mixed and used to ferment and decompose corn straw at a mass ratio of 1 - 19:19 - 1, the EC 50 values of the fermentation and decomposition liquid against Ralstonia solanacearum were lower than those of either agent used alone. In particular, when the mass ratio of the two was 1:9, the EC 50 value against Ralstonia solanacearum was the lowest and was significantly lower than that of Brevibacillus laterosporus A60 and Bacillus velezensis CGMCC No. 14384 used alone. This indicates that the decomposing agent of the present invention has a synergistic effect in inhibiting soil-borne bacterial diseases.

Claims

1. A novel straw composting agent, characterized in that: The novel straw composting agent is a mixture of Brevibacillus laterosporus and Bacillus velezii; wherein the Brevibacillus laterosporus is a Brevibacillus laterosporus A60 suspension concentrate with a content of 500 million cfu / mL; and the Bacillus velezii is a Bacillus velezii CGMCC No.14384 water dispersible granules with a content of 20 billion live spores / gram.

2. The novel straw composting agent according to claim 1, characterized in that: The mass ratio of Brevibacillus laterosporus to Bacillus velezii is 1-19:19-1.

3. The novel straw composting agent according to claim 1, characterized in that: The mass ratio of Brevibacillus laterosporus to Bacillus velezii is 1:

9.

4. Use of the novel straw composting agent according to any one of claims 1 to 3 in preventing and controlling soil-borne bacterial diseases.

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