Quorum sensing protects bacterial co-operation from exploitation by cheats

Richard C Allen, Luke McNally, Roman Popat, Sam P Brown

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Quorum sensing (QS) is a cell-cell communication system found in many bacterial species, commonly controlling secreted co-operative traits, including extracellular digestive enzymes. We show that the canonical QS regulatory architecture allows bacteria to sense the genotypic composition of high-density populations, and limit co-operative investments to social environments enriched for co-operators. Using high-density populations of the opportunistic pathogen Pseudomonas aeruginosa we map per-capita signal and co-operative enzyme investment in the wild type as a function of the frequency of non-responder cheats. We demonstrate mathematically and experimentally that the observed response rule of 'co-operate when surrounded by co-operators' allows bacteria to match their investment in co-operation to the composition of the group, therefore allowing the maintenance of co-operation at lower levels of population structuring (that is, lower relatedness). Similar behavioural responses have been described in vertebrates under the banner of 'generalised reciprocity'. Our results suggest that mechanisms of reciprocity are not confined to taxa with advanced cognition, and can be implemented at the cellular level via positive feedback circuits.The ISME Journal advance online publication, 8 January 2016; doi:10.1038/ismej.2015.232.

Original languageEnglish
JournalThe ISME Journal: Multidisciplinary Journal of Microbial Ecology
Early online date8 Jan 2016
Publication statusE-pub ahead of print - 8 Jan 2016


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