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CN-122004249-A - Microbial bactericide and application thereof

CN122004249ACN 122004249 ACN122004249 ACN 122004249ACN-122004249-A

Abstract

The invention discloses a microbial bactericide and application thereof, comprising a functional microbial composite microbial agent, a targeting phage composition, a pH response type nanogel carrier and an auxiliary agent, wherein the functional microbial composite microbial agent comprises bacterial strains which are separated from deep sea sediments and have a diameter of more than or equal to 15mm for at least one target pathogenic bacteria inhibition zone through a flat plate counter method screening, the targeting phage composition comprises at least two lytic phages, the lytic phages specifically lyse different types in pathogenic bacteria of the genus of ralstonia solanacearum, pseudomonas syringae and erwinia respectively, and four mechanisms of competitive occupation, antibacterial substance inhibition, phage lysis and induced system resistance are integrated, so that the limitation of a single action mode is broken through.

Inventors

  • YAN XIUXIANG

Assignees

  • 黑龙江省金凤凰农业发展有限公司

Dates

Publication Date
20260512
Application Date
20260204

Claims (10)

  1. 1. A microbial germicide, characterized by comprising the following components: functional microorganism composite microbial agent, targeting phage composition, pH response type nanogel carrier and auxiliary agent; The functional microorganism composite microbial agent comprises bacterial strains which are separated from deep sea sediment and have a diameter of more than or equal to 15mm for at least one target pathogenic bacteria inhibition zone through a flat plate counter method, wherein the targeting phage composition comprises at least two lytic phages, and the lytic phages specifically lyse different types in pathogenic bacteria of the genus of Ralstonia, pseudomonas syringae and Erwinia respectively.
  2. 2. The microbial sterilant according to claim 1 wherein the strain comprises at least two different genera of bacillus, pseudomonas and streptomyces.
  3. 3. The microbial fungicide according to claim 2, wherein the functional microbial composite fungicide is compounded by live bacteria of bacillus strains, pseudomonas strains and streptomyces strains according to a ratio of live bacteria number of (1-3): (0.5-1.5): (0.5-1.5), and the total live bacteria number is not less than 1.0x10 10 CFU/g.
  4. 4. The microbial sterilant according to claim 1 wherein the total titer of the targeted phage composition is not less than 1.0 x 10 9 PFU/g.
  5. 5. The microbial bactericide according to claim 1, wherein the pH-responsive nanogel carrier is a biopolymer crosslinked polymer which swells or degrades in an environment with pH of 5.0-6.5 to release active ingredients, wherein the active ingredients comprise the functional microbial composite bactericide and/or the targeting phage composition.
  6. 6. The microbial fungicide according to claim 5, wherein the pH-responsive nanogel carrier comprises a gelatin-pectin complex crosslinked by calcium ions, the particle size of which is 50-300nm, and the encapsulation efficiency of the active ingredient is not less than 80%.
  7. 7. The microbial bactericide according to claim 1, wherein the mass percentages of the components based on the total weight of the bactericide are: 30% -50% of functional microorganism composite microbial agent, 10% -20% of targeting phage composition, 20% -30% of pH response type nano gel carrier and the balance of auxiliary agent.
  8. 8. The microbial sterilant according to claim 1 wherein the adjuvant comprises at least one of a dispersant, an ultraviolet protectant and a lyoprotectant, the ultraviolet protectant comprising a mixture of trehalose and nano-titania.
  9. 9. Use of a microbial fungicide according to any one of claims 1 to 8 in the preparation of a formulation for the control of plant diseases, which are soil borne diseases or bacterial foliar diseases.
  10. 10. The use according to claim 9, wherein the soil-borne disease is tomato bacterial wilt or cucumber fusarium wilt and the bacterial leaf disease is cucumber angular leaf spot or tobacco wildfire.

Description

Microbial bactericide and application thereof Technical Field The invention belongs to the technical field of agricultural biological control, and particularly relates to a microbial bactericide and application thereof. Background Plant diseases, especially diseases caused by soil borne pathogens (such as ralstonia solanacearum Ralstoniasolanacearum, fusarium spp.) and foliar pathogens (such as pseudomonas Pseudomonassyringae, erwinia Erwiniaamylovora), are one of the main causes of reduced yield and reduced quality of crops worldwide. At present, disease control mainly depends on chemical pesticides, but long-term use is easy to cause the problems of enhanced drug resistance of pathogenic bacteria, exceeding of pesticide residues, ecological environment pollution and the like. Biological control is a research hotspot due to its environmental friendliness and sustainability. In the prior art, microbial bactericides are mostly compounded by adopting single strains or homologous strains, for example: Bacillus subtilis preparation can inhibit pathogenic bacteria by secreting lipopeptid antibiotics, but has limited effect on established pathogenic bacteria groups, and has large control effect influenced by environmental factors. Trichoderma (Trichoderma spp.) formulations have competitive and re-parasitic effects, but slow rates of action and are ineffective against bacterial diseases. The single phage preparation can specifically lyse target pathogenic bacteria, but has narrow host range, is easy to be inactivated by ultraviolet rays and has weak diffusion capability in soil. Limitations of the prior art mainly include: the function is single, most products only depend on one action mechanism (such as antagonism and competition), and complex diseases are difficult to deal with. The lasting period is short, and the live bacteria preparation is easy to be inactivated by the environmental influences of temperature, ultraviolet rays, drying and the like in the field. Slow effect, colonization and reproduction of biocontrol bacteria in the required time and untimely control of outbreak diseases. Poor stability, easy inactivation of phage in environment, and great activity loss during preparation process. The lack of intelligent response is that the release of active ingredients is uncontrollable and can not be accurately released when pathogenic bacteria are active. Therefore, development of a novel compound microbial bactericide which is synergistic in multiple mechanisms, strong in environmental adaptability, long in lasting period and capable of intelligent response is needed. Disclosure of Invention In order to meet the above-mentioned needs, the present invention provides a microbial sterilant and its use to at least partially solve the above-mentioned problems. According to the technical scheme, the invention provides a microbial bactericide, which comprises the following components in percentage by weight: 30% -50% of functional microorganism composite microbial agent (the total number of viable bacteria is more than or equal to 1.0X10 10 CFU/g); 10% -20% of targeting phage composition (calculated by phage titer is more than or equal to 1.0X10 9 PFU/g); 20-30% of pH response type nano gel carrier; Adjuvant (including dispersant, ultraviolet protectant and freeze-drying protectant) and the rest. 1. Functional microorganism composite microbial agent The bacterial strain is prepared by compounding the following three bacterial strains screened from deep sea sediments according to the ratio of the viable count: Bacillus strain, marine bacillus with accession number PD 20142272. Pseudomonas fluorescens strain, cat No. CICC 10282. Streptomyces strain Streptomyces sp with the product number HZB 269487. Screening and culturing conditions: The strain is separated from deep sea sediment with depth of more than 1000m and temperature of 4-10 ℃, the primary screening of an oligotrophic culture medium is adopted, and then the strain with the diameter of a bacteriostasis ring of target pathogenic bacteria being more than or equal to 15mm is screened by a plate counter method. The fermentation medium is modified seawater basal medium, and 0.5% corn flour and 0.1% yeast extract are added, pH is 7.2-7.5, fermentation temperature is 28-30deg.C, aeration rate is 1:1vvm, and fermentation time is 48-72h. 2. Targeted phage compositions An equal proportion mix comprising two or more phages: Lytic phage 1 bacterial wilt phage preparation xiaoqingning produced by wuhan gerimunon biotechnology limited company. Lytic phage 2 Pseudomonas phage GoldenEco produced by Israel EcoPhage. Lytic phage 3 fire blight phage preparation EcoFire produced by Israel EcoPhage. Phage preparation: Separating from the diseased plant tissue by a double-layer agar plate method, and culturing, fermenting and proliferating by host bacteria, wherein the fermentation termination titer is more than or equal to 1.0X10 11 PFU/mL. Purification high purity phage par