莱氏野村菌CQNr01微菌核的人工诱导培养

摘要

[Objective] The objective of this study is to induce microsclerotia (MS) of Nomuraea rileyi strain CQNr01, and to provide a novel preparation type and production process for insects control with this entomopathogenic fungus. [ Method ] The CQNrOI was cultured in liquid medium containing special salts solutions and medium components including concentration of carbon, nitrogen and their ratio were optimized. Germination rates of microsclerotia and the pathogenicity in larvae of Spodoptera litura were determined with the dried and preserved microsclerotia. [Result] The MS with cell structural differentiated and pigmentation was induced successfully under the optimized cultural conditions. The MS yield was affected by carbon concentrations and carbon-to-nitrogen ratios. Within a certain point the medium with lower carbon concentrations produced more MS at same carbon-to-nitrogen ratio. Microsclerotial granules of N. rileyi CQNr01 were siccostabile. The microsclerotia mixed with diatomite, air-dried and kept in storage for 6 month had no significant loss in viability. After rehydrating and incubating in water agar plates, MS could germinate and produce conidia. Bioassays results showed that the dried MS preparations can infect the larvae of 5. litura and the corrected mortality was 78.56% in 14 d after inoculation. The LT50 was about 7 d at the tested dosage. [Conclusion] Microsclerotia of N. rileyi CQNrOI can be induced by specific medium components in liquid culture. The induced microsclerotia remain activity and keep high infective ability to kill insects. The microsclerotia might be used as the potential bio-pesticide agent for insect biological control.%[目的]诱导莱氏野村菌的微菌核形成,为该菌靶标害虫的生物防治提供新的制剂类型和生产工艺.[方法]采用包含特定盐离子成分的液体培养基进行诱导培养,并对培养基中的碳、氮源浓度及碳氮比例进行优化；将微菌核干燥保存后复水测定菌核萌发率及对斜纹夜蛾幼虫的致病力.[结果]优化筛选出莱氏野村菌CQNr01微菌核诱导培养基,成功诱导莱氏野村菌菌株CQNr01产生细胞结构分化、色素沉着的微菌核结构；微菌核的产生数量受培养基中碳和氮素含量和相对比例的影响,在一定范围内,同样碳氮比情况下,低碳培养液有利于微菌核的产生.微菌核耐干燥保存,掺加硅藻土制备的微菌核制剂经干燥处理并贮存6个月吸水后仍能萌发产孢.微菌核制剂对斜纹夜蛾幼虫具有侵染活性,接种14d后,供试昆虫的校正死亡率可达78.56％,供试浓度下,LT50约为7d.[结论]莱氏野村菌的微菌核受特定培养基成分的诱导,获得的微菌核耐干燥且对寄主害虫具有很高的致死率,可以作为该菌生防制剂开发应用.