Bt生物被膜对其定殖能力及杀蛴螬活性调控研究

蛴螬栖居地下，为害隐蔽，且呈日益严重的趋势，目前尚缺乏有效防治措施。由于土壤生态的复杂性和蛴螬的生物学特性，"特异、高效、持久"是蛴螬防治的重要保证。我们已经筛选到对蛴螬高效的Bt菌株，但其在土壤中的持效期相对较短，限制了其在蛴螬防治中的应用。本项目以与细菌定殖密切相关的细菌生物被膜（BBF）为切入点，在前期筛选获得4株生物膜形成能力较强的菌株、并进行了测序的基础上，拟通过筛选、敲除Bt BBF形成相关的功能基因（如：sigB、fla等），构建BBF形成能力改变的突变体，比较突变体的土壤、根际定殖能力以及对蛴螬的杀虫活性，解析具有形成BBF的Bt菌株与其定殖能力关系，从而明确BBF对害虫防治的重要作用，本研究的成果将丰富生物被膜在有益微生物中的应用，同时将为抗蛴螬Bt杀虫剂的研制提供新的研究思路。

White grubs which inhabit in the soil cause serious damage with a growing trend. No effective techniques have been developed to control white grubs. For the complicacy of soil ecological environment and grubs biological characteristics, the specific, high efficiency and lasting are basic requirements for white grubs biocontrol. We have screened white grubs-specific and efficient Bt strains, but its persistence in the soil is relatively short, and that hindered application of Bt in white grubs biocontrol. In this project, we take the bacterial biofilm (BBF) as the starting point, which is closely related to bacterial colonization. Based on four strains with high biofilm formation ability obtained and sequenced, we will screen and knockout the functional genes (e.g. sigB, fla) related to Bt BBF formation, construct the BBF formation ability changed mutants, analyze these mutants colonization ability in soil and rhizosphere, and their toxicity against white grubs，clear and indicate the effect of BBF on Bt clonzation in soil and rhizosphere, and toxicity agaist white grubs. These results will extense the BBF appliction in beneficial microorganisms and provide research mentality for anti-grubs Bt insecticide research and development.