亚热带森林土壤分子生态网络中粘细菌-细菌捕食关系的解析

Myxobacteria is one of the most abundant taxa in soil, and the predatory interaction between myxobacteria and prey bacteria is also one of the most important interactions existing in soil. The combined use of high-throughput sequencing and ecological molecular network has been developed recently. However, the interaction network analysis has more often served as a visual means to compare microbial communities from different environments than as a mean to appreciate microbial interactions associated with certain ecological processes. Previous studies often described a subnetwork as a functional related unite, but the authenticity of the interactions and the real functionality in ecological context have seldomly been evidenced. Therefore, it is necessary to explore the potential interactions in the network and figure out those interactions that are real ecological processes. Based on the predatory interaction, we isolated more than 300 myxobacterial strains from subtropical forest soil and litter using prey as induction, indicating this interaction is common in this area. This project will collect soil samples from different climate zones and different layers in the virgin forests in Guangdong province, focusing on the interactions between myxobacteria and other soil bacteria based on ecological molecular network. The predation interactions are distinguished from the predicted network using isolation of potential prey bacteria from soil samples. And efficient prey bacteria will be confirmed. The certain predatory processes will be confirmed by the induction of myxobacteria using the obtained efficient prey bacteria. The results from this project will help to identify ecologically meaningful predatory associations between myxobacteria and prey bacteria, which will promote the isolation of the uncultured myxobacterial resources.

粘细菌是土壤中最主要的类群之一，其捕食关系是土壤主要的互作关系之一。近年来，采用基于高通量测序的分子生态网络研究群落水平上微生物间的互作关系开始发展起来，然而，目前相关研究仅停留在描述阶段，网络预测关系的可靠性有待证实。因此有必要对分子生态网络提供的潜在互作关系进行深度解析，确定环境中真实发生的互作。本项目组利用捕食关系已从热带亚热带森林分离了300多株粘细菌，表明该生境中粘细菌-细菌捕食关系的普遍存在。因此本项目拟采集中、南亚热带森林土壤及土壤剖面样品，以粘细菌-细菌互作关系为研究对象，基于免培养方法构建细菌分子生态互作网络；通过分离样品中的潜在被捕食菌，辨识分子生态网络中的粘细菌-细菌捕食关系，获得高效的被捕食菌；用高效被捕食菌诱导粘细菌子实体的形成，解析森林土壤不同环境中的真实捕食关系。研究结果能够将预测的互作关系与实际的生物学关系联系起来，进而推动粘细菌这一难培养菌的新资源挖掘。