LAUSR

Significance Microbial communities have been implicated in human and plant disease and are essential to global biogeochemical cycles. However, our ability to reliably alter these communities is limited by insufficient understanding of the networks that drive community processes. The goal of this study was to understand how community membership alters secondary metabolism in a model microbial community. We found that community species composition affects expression of biosynthetic genes and abundance of metabolites. Dramatic changes were observed when the biosynthetic gene cluster of one metabolite, koreenceine, was deleted, suggesting that interspecies interaction networks may be driven by secondary metabolites. This work offers an approach to dissecting the flow of information through communities, which could lead to strategies for manipulating community function.