C. elegans avoids toxin-producing Streptomyces using a seven transmembrane domain chemosensory receptor

Abstract

Predators and prey co-evolve, each maximizing their own fitness, but the effects of predator-prey interactions on cellular and molecular machinery are poorly understood. Here, we study this process using the predator <i>Caenorhabditis elegans</i> and the bacterial prey <i>Streptomyces,</i> which have evolved a powerful defense: the production of nematicides. We demonstrate that upon exposure to <i>Streptomyces</i> at their head or tail, nematodes display an escape response that is mediated by bacterially produced cues. Avoidance requires a predicted G-protein-coupled receptor, SRB-6, which is expressed in five types of amphid and phasmid chemosensory neurons. We establish that species of <i>Streptomyces</i> secrete dodecanoic acid, which is sensed by SRB-6. This behavioral adaptation represents an important strategy for the nematode, which utilizes specialized sensory organs and a chemoreceptor that is tuned to recognize the bacteria. These findings provide a window into the molecules and organs used in the coevolutionary arms race between predator and potential prey.