title: Social conflict drives the evolutionary divergence of quorum sensing.
abstract: In microbial "quorum sensing" (QS) communication systems, microbes produce and respond to a signaling molecule, enabling a cooperative response at high cell densities. Many species of bacteria show fast, intraspecific, evolutionary divergence of their QS pathway specificity--signaling molecules activate cognate receptors in the same strain but fail to activate, and sometimes inhibit, those of other strains. Despite many molecular studies, it has remained unclear how a signaling molecule and receptor can coevolve, what maintains diversity, and what drives the evolution of cross-inhibition. Here I use mathematical analysis to show that when QS controls the production of extracellular enzymes--"public goods"--diversification can readily evolve. Coevolution is positively selected by cycles of alternating "cheating" receptor mutations and "cheating immunity" signaling mutations. The maintenance of diversity and the evolution of cross-inhibition between strains are facilitated by facultative cheating between the competing strains. My results suggest a role for complex social strategies in the long-term evolution of QS systems. More generally, my model of QS divergence suggests a form of kin recognition where different kin types coexist in unstructured populations.
authors.affiliation: Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel. avigdore@tau.ac.il
authors.forename: Avigdor
authors.initials: A
authors.lastname: Eldar
mesh_terms: D001419:Bacteria / Q000235:genetics*; D018407:Bacterial Physiological Phenomena; D005075:Biological Evolution; D019143:Evolution, Molecular; D009154:Mutation; D053038:Quorum Sensing / Q000235:genetics* / Q000502:physiology; D013045:Species Specificity