黄瓜枯萎病拮抗菌的筛选及其生防效应的研究

发布时间：2018-06-11 10:06

  本文选题：拮抗菌 + 筛选　； 参考：《内蒙古师范大学》2017年硕士论文

【摘要】：黄瓜是一种世界性蔬菜作物,黄瓜枯萎病作为一种土传病害,是世界各国黄瓜生产中的主要病害之一,由尖孢镰刀菌(Fusarium oxysporum)引发。长期以来,化学农药在黄瓜枯萎病的防治方面发挥了重要作用,但过度使用化学农药,容易使病菌产生抗药性、降低黄瓜品质、污染环境、影响人体健康。因此采用高效、安全、环境友好型生物防治成为最佳选择。本研究通过平板对峙实验,从分离自青海湖周边土壤的菌株中筛选出对黄瓜枯萎病原菌具有良好的抑制作用的拮抗细菌246-1和拮抗放线菌11F,其中拮抗细菌246-1对黄瓜枯萎病原菌的抑菌率为60%;而拮抗放线菌对黄瓜枯萎病原菌的抑菌率为68.6%,并发现这两株拮抗菌对其他病原菌也有不同程度的拮抗作用,显示了其具有抑菌广谱性。通过对拮抗菌株进行表型鉴定、生理生化鉴定和分子生物学鉴定,确定拮抗菌株246-1为多粘类芽孢杆菌(Paenibacillus polymyxa),而拮抗放线菌11F为黄赭色链霉菌(Streptomyces silaceus)。采用抑菌圈实验筛选出最适合多粘类芽孢杆菌246-1产拮抗物质的培养基,用单因素实验方法对其培养条件进行优化。结果表明,246-1菌株的培养基配方为可溶性淀粉17.5 g·L-1,酵母浸出粉4 g·L-1,蛋白胨25g·L-1,Na Cl 1.25 g·L-1,Na2HPO4 0.5 g·L-1,Ca Cl2 1g·L-1,蔗糖15 g·L-1,最佳培养时间48 h,初始p H 7.0,培养温度30℃。通过筛选fusaricidins提取纯化和检测方法,确定发酵液酸化是fusaricidins提取纯化的一个重要步骤,同时确定乙腈/水/TFA检测体系为fusaricidins HPLC检测流动相。并进一步分析了多粘类芽孢杆菌246-1对黄瓜幼苗的促生作用,在黄瓜幼苗根际土壤中的定殖能力和对黄瓜枯萎病的防效作用。盆栽试验结果表明,菌株246-1的发酵液对黄瓜枯萎病菌表现出很强的抑制作用,同时该菌株在黄瓜幼苗根际具有很好的定殖能力,表现了对黄瓜幼苗的显著促生效果。这些生防效应的研究为研制微生物可湿性粉剂和有生物有机肥提供了基础依据。
[Abstract]:Cucumber wilt is a worldwide vegetable crop. As a soil-borne disease, cucumber wilt is one of the major diseases in cucumber production in the world, which is caused by Fusarium oxysporum (Fusarium oxysporum). For a long time, chemical pesticides have played an important role in the control of cucumber wilt. However, excessive use of chemical pesticides can easily lead to drug resistance, reduce cucumber quality, pollute the environment and affect human health. Therefore, it is the best choice to adopt high efficiency, safety and environment-friendly biological control. In this study, plate confrontation experiments were carried out, The antagonistic bacteria 246-1 and 11F were screened from the soil around Qinghai Lake to inhibit the pathogen of cucumber wilt, and the inhibitory rate of the antagonistic bacteria 246-1 to the pathogen of cucumber wilt was 60%. The inhibition rate of antagonistic actinomycetes against cucumber wilt pathogen was 68.6, and it was found that these two antagonistic bacteria also had antagonistic effects on other pathogens. It is shown that it has broad spectrum of bacteriostasis. By phenotypic identification, physiological and biochemical identification and molecular biological identification, the antagonistic strain 246-1 was identified as Paenibacillus polymyxa1, and the antagonistic actinomycetes 11F was Streptomyces silaceusus. The best medium for producing antagonist substance of Bacillus polymyxis 246-1 was screened by inhibition circle experiment, and the culture conditions were optimized by single factor experiment. The results showed that the culture medium was soluble starch 17.5 g L -1, yeast extract 4 g L -1, peptone 25 g L -1 NaCl 1.25 g L -1 Na 2HPO 4 0.5 g L -1 Ca Cl 2 1g L -1, sucrose 15 g L -1, the optimum culture time 48 h, initial pH 7.0, culture temperature 30 鈩，

本文编号：2004869