title: Detection and avoidance of a natural product from the pathogenic bacterium Serratia marcescens by Caenorhabditis elegans.
abstract: The nematode Caenorhabditis elegans is present in soils and composts, where it can encounter a variety of microorganisms. Some bacteria in these rich environments are innocuous food sources for C. elegans, whereas others are pathogens. Under laboratory conditions, C. elegans will avoid certain pathogens, such as Serratia marcescens, by exiting a bacterial lawn a few hours after entering it. By combining bacterial genetics and nematode genetics, we show that C. elegans specifically avoids certain strains of Serratia based on their production of the cyclic lipodepsipentapeptide serrawettin W2. Lawn-avoidance behavior is chiefly mediated by the two AWB chemosensory neurons, probably through G protein-coupled chemoreceptors, and also involves the nematode Toll-like receptor gene tol-1. Purified serrawettin W2, added to an Escherichia coli lawn, can directly elicit lawn avoidance in an AWB-dependent fashion, as can another chemical detected by AWB. These findings represent an insight into chemical recognition between these two soil organisms and reveal sensory mechanisms for pathogen recognition in C. elegans.
authors.affiliation: Centre d'Immunologie de Marseille-Luminy, Université de la Méditerranée, Case 906, 13288 Marseille Cedex 9, France.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Pradel
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
authors.forename: Nathalie
authors.initials: N
authors.lastname: Pujol
authors.forename: Tohey
authors.initials: T
authors.lastname: Matsuyama
authors.forename: Cornelia I
authors.initials: CI
authors.lastname: Bargmann
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Ewbank
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D001688:Biological Products / Q000378:metabolism / Q000494:pharmacology; D017173:Caenorhabditis elegans / Q000382:microbiology* / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000502:physiology; D008074:Lipoproteins / Q000378:metabolism / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000502:physiology; D010456:Peptides, Cyclic / Q000378:metabolism / Q000494:pharmacology*; D012706:Serratia marcescens / Q000737:chemistry*
chemical_list: D001688:Biological Products; D029742:Caenorhabditis elegans Proteins; D008074:Lipoproteins; D009419:Nerve Tissue Proteins; D010456:Peptides, Cyclic; C439300:Tol-1 protein, C elegans; C073497:serrawettin W2