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Cooperation and conflict in quorum-sensing bacterial populations


It has been suggested that bacterial cells communicate by releasing and sensing small diffusible signal molecules in a process commonly known as quorum sensing (QS)1,2,3,4. It is generally assumed that QS is used to coordinate cooperative behaviours at the population level3,5. However, evolutionary theory predicts that individuals who communicate and cooperate can be exploited6,7,8,9,10. Here we examine the social evolution of QS experimentally in the opportunistic pathogen Pseudomonas aeruginosa, and show that although QS can provide a benefit at the group level, exploitative individuals can avoid the cost of producing the QS signal or of performing the cooperative behaviour that is coordinated by QS, and can therefore spread. We also show that a solution to the problem of exploitation is kin selection, if interacting bacterial cells tend to be close relatives. These results show that the problem of exploitation, which has been the focus of considerable attention in animal communication, also arises in bacteria.

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Figure 1: QS-controlled public goods provide a benefit at the population level in QSM.
Figure 2: QS-dependent cooperation is costly.
Figure 3: QS is subject to cheating.
Figure 4: Kin selection and QS.


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We thank P. Williams and R. Chhabra for the provision of AHL compounds; D. Jackson for comments on the manuscript; and A. Ross-Gillespie for help in analysing the data. We acknowledge funding from the Royal Society and the Leverhulme Trust.

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Correspondence to Stephen P. Diggle or Stuart A. West.

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Diggle, S., Griffin, A., Campbell, G. et al. Cooperation and conflict in quorum-sensing bacterial populations. Nature 450, 411–414 (2007).

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