细菌之间通过小型可扩散分子的释放和感应（或群体感应）来进行的通信，被认为是在种群层面上协调合作行为的一种方式。演化理论预测，彼此进行沟通和合作的个体还能被“骗子”所利用，后者要么不发出信号，要么不对信号作出反应。现在，对病原体绿脓杆菌（它们在细胞之间通过信号进行联系来调控毒性因子表达）的种群所做的实验证实，信号和信号受体突变体（或称“欺骗信号”）的确都有一个适应优势。但对欺骗问题的解决办法的确以亲缘选择的形式而存在——近亲之间倾向于进行“诚实的”沟通。这些发现为在人体细菌感染中所观测到的欺骗信号的传播提供了一个解释。
原始出处:
Nature 450, 411-414 (15 November 2007) | doi:10.1038/nature06279; Received 29 June 2007; Accepted 18 September 2007
Cooperation and conflict in quorum-sensing bacterial populations
Stephen P. Diggle1, Ashleigh S. Griffin2, Genevieve S. Campbell1 & Stuart A. West2
Institute of Infection, Immunity & Inflammation, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK
Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, King's Buildings, Edinburgh EH9 3JT, UK
Correspondence to: Stephen P. Diggle1Stuart A. West2 Correspondence and requests for materials should be addressed to S.P.D. (Email: steve.diggle@nottingham.ac.uk) or S.A.W. (Email: stu.west@ed.ac.uk).
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.
