Evolution and Ecology of Streptomyces

<i>Streptomyces</i> are among the most well-studied and important groups of bacteria, largely owing to their prolific production of biomedically important compounds like antibiotics and antifungals. Research over more than a half-century has elucidated the molecular and mechanistic details of <i>Streptomyces</i> multicellular development and the production of secondary metabolites. In contrast, the evolutionary and ecological mechanisms that underlie these phenotypes are comparatively understudied. Our aim in this review is to examine these aspects of <i>Streptomyces</i> biology, with a focus on the benefits associated with their complex life cycle, their multicellular architecture and development, and their production of antibiotics. In addition to highlighting existing studies, we point to clear knowledge gaps that can serve to motivate further research on these bacteria. A greater understanding of <i>Streptomyces</i> evolution and ecology is needed to improve our ability to exploit these organisms for biomedical and agricultural applications.