细菌与宿主的相互关系一直是生物学研究领域的前沿热点，也是植物寄生线虫病害生物防控的重要理论基础。但目前该领域仍多为聚焦于单一基因的独立研究。本项目拟在前期对病原细菌Bacillus nematocida B16侵染线虫过程已有深入认识的基础上,完成该菌株全基因组测序。进而选取芽孢杆菌属中其它对线虫具有不同毒杀活性、以及杀线虫方式不同的近缘菌株，围绕该菌株侵染宿主的主要步骤，借助于比较基因组学等工具，寻找与侵染各阶段相关的候选基因。同时，筛选该菌株随机突变文库中侵染各阶段具有表型变化的典型突变子。综合以上两种水平获得的致病候选基因，再通过qPCR、荧光定位、基因敲除或过表达等功能实验对重要基因进行验证。本研究尝试从遗传背景、基因含量、基因种类、基因表达调控方式的不同，阐明芽孢杆菌属中不同物种之间拮抗线虫活性的差异以及杀虫方式的差异，以期在组学水平上更全面地揭示线虫病原细菌侵染宿主的分子机制。

Understanding the mechanisms of host-pathogen interaction has always been the frontier and hot point in biological researches. The knowledge is also the most important theoretical principle for biocontrol of plant parasitic nematodes. But now, most of the investigations in this area only deal on the single gene. Therefore based on our previous study to describe the process of pathogenic bacterium Bacillus nematocida B16 infecting nematodes, we shall complete the genomic sequence of this bacterial strain. Meantime, we shall also select the different bacterial strains in the genus Bacillus, which have the different nematocidal activities or/and different strategies to kill nematodes. Then employing the methods such as comparative genomics and transcriptomics/proteomics, we try to identify the candidate genes involved in the different stages of infection. Furthermore, we shall screen a random mutant library of B. nematocida B16 for the typical mutants with attenuated nematicidal activities at the different stages after success construction of the random mutant library. Combined with these two methods above, a variety of candidate genes responsible for the infectious process will be obtained. Finally, we shall use the functional experiments, including qPCR, fluorescent localization, gene knockout or overexpression, to validate the important candidate genes. In conclusion, analyzing the data of genetics background, gene types, gene quantities, and gene expressional regulation, our investigation tries to explain the different interaction relashionships between bacteria and nematodes as well as the different strategies of infection among Bacillus, which also helps to reveal the comprehensive and systematic mechanisms of infection at genomic level.