title: Facultative cheating supports the coexistence of diverse quorum-sensing alleles.
abstract: Bacterial quorum sensing enables bacteria to cooperate in a density-dependent manner via the group-wide secretion and detection of specific autoinducer molecules. Many bacterial species show high intraspecific diversity of autoinducer-receptor alleles, called pherotypes. The autoinducer produced by one pherotype activates its coencoded receptor, but not the receptor of another pherotype. It is unclear what selection forces drive the maintenance of pherotype diversity. Here, we use the ComQXPA system of Bacillus subtilis as a model system, to show that pherotype diversity can be maintained by facultative cheating--a minority pherotype exploits the majority, but resumes cooperation when its frequency increases. We find that the maintenance of multiple pherotypes by facultative cheating can persist under kin-selection conditions that select against "obligate cheaters" quorum-sensing response null mutants. Our results therefore support a role for facultative cheating and kin selection in the evolution of quorum-sensing diversity.
authors.affiliation: Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Shaul
authors.initials: S
authors.lastname: Pollak
authors.affiliation: Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Shira
authors.initials: S
authors.lastname: Omer-Bendori
authors.affiliation: Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Eran
authors.initials: E
authors.lastname: Even-Tov
authors.affiliation: Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Valeria
authors.initials: V
authors.lastname: Lipsman
authors.affiliation: Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Tasneem
authors.initials: T
authors.lastname: Bareia
authors.affiliation: Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Ishay
authors.initials: I
authors.lastname: Ben-Zion
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: D000483:Alleles; D001412:Bacillus subtilis / Q000235:genetics* / Q000502:physiology*; D005075:Biological Evolution; D005798:Genes, Bacterial; D014644:Genetic Variation; D008954:Models, Biological; D008957:Models, Genetic; D009154:Mutation; D053038:Quorum Sensing / Q000235:genetics* / Q000502:physiology
keywords: Bacillus subtilis; bacteria; quorum sensing; social evolution; sociomicrobiology