根结线虫胁迫下根际细菌群落的组成和功能响应机制

Root–knot nematode（RKN）is an important crop disease. Rhizosphere bacterial flora are closely related to the occurrence, epidemic and biocontrol of RKN. Our previous research had analyzed the relationships of rhizosphere bacterial community, environmental factors and RKN infection by comparing the rhizosphere bacterial flora of RKN–infected and healthy tobacco in large–scale geographical rang. In this study, bacterial community variation of RKN correlated bacteria，rhizosphere bacteria and environmental factors will be investigated at the temporal scale in typical field infected with RKN using pyrosequencing–based analysis and multivariate statistical analysis. Functional response mechanism of rhizosphere bacteria community to the RKN infection will be conducted by metagenomics analysis of gene composition, function and metabolism network at different development stage of tobacco. Method such as culture dependent, antagonistic activity to nematode，pot experiment in greenhouse and real–time PCR will be designed and applied to assess the colonization in rhizosphere and biocontrol effect of representative RKN correlated bacteria strains. The results will help to elucidate the ecological relationship of RNK – rhizobacterial flora and lay a foundation for utilizing rhizosphere bacteria as RKN biological control agent.

根结线虫是重要的作物病害，根结线虫病的发生、流行及生物防治效果与根际微生物群落密切相关。本项目拟在已完成大尺度地理生境下感染根结线虫和健康烟草根际土壤细菌群落特征、影响因子及根结线虫显著关联菌群对比分析的基础上，对典型根结线虫病地不同年季烟草根际细菌组成和多样性进行高通量测序分析，结合土壤理化性质、温度、病指等因子，解析根际细菌群落和根结线虫显著关联菌群在时间尺度上的动态变化规律；利用宏基因组方法,分析关键阶段根际菌群的基因组成、功能和代谢网络，揭示根结线虫胁迫下根际菌群的功能响应机制；通过细菌纯培养、抗虫活性测试、温室盆栽、定量PCR等方法，分析代表性线虫显著关联细菌的根际定殖特征及其对根结线虫的生物防治效果。项目的实施有助于揭示根际细菌与线虫的生态互作关系，为高效、稳定根际生防细菌的开发利用奠定基础。

根结线虫病的发生、流行及生物防治效果与根系微生物密切相关，项目在前期大尺度地理生境下感染根结线虫和健康烟草根际土壤细菌群落特征和线虫显著关联菌群对比分析的基础上，本项目连续两季对南方根结线虫典型病地和健康生长地块烟草根系微生物组进行全生育期监测分析，研究根系微生物组在不同年度、不同生长发育阶段的变化规律及根结线虫感染显著关联的菌群，预测分析根系微生物群落对线虫侵染的响应机制。随后，采用高通量培养组学相关方法对根际细菌资源进行分离培养，通过测试线虫显著关联的代表性细菌的抗病活性，筛选根结线虫关联菌群中的抗病功能菌株。本研究为根结线虫-根际细菌-植物互作机理和根结线虫高效生防菌的挖掘利用奠定基础。