Determining causal links between interaction type and network structure in microbial communities

点击翻译按钮获取中文摘要

Ecological communities exist as networks of interacting species, and the structure of these networks determine their stability and function. Observational studies suggest that network structure depends upon whether interactions between species are predominantly mutualistic or antagonistic, however the causality of this relationship remains unclear. Here, we will use communities of bacteria and their symbiotic plasmids to experimentally determine how interaction type (mutualistic versus antagonistic) affects community network structure. Our system is ideal to address these questions because bacteria-plasmid interactions can be switched from antagonistic to mutualistic through simple environmental manipulations (the addition of antibiotics to which the plasmids confer resistance), and changes in community network structure can be observed over a matter of weeks. The large-scale of this project is made possible by the application of a novel culture-free method, epicPCR, which allows high-throughput assessment of bacteria-plasmid associations. The predicted role of ecological stability, as well as novel eco-evolutionary mechanisms, underpinning the interaction type-network structure relationships will be assessed by a combination of phenotypic and genetic experiments complemented by theory.