Combinatorial quorum sensing in Pseudomonas aeruginosa allows for novel cheating strategies
Combinatorial quorum sensing in Pseudomonas aeruginosa allows for novel cheating strategies
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DOI：
10.1099/mic.0.000941
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发表时间：
2020-08-01
期刊：
影响因子：
2.8
通讯作者：
Diggle, Stephen P.
中科院分区：
文献类型：
--
作者：
Gurney, James;Azimi, Sheyda;Diggle, Stephen P.
在机会致病菌铜绿假单胞菌中，群体感应（quorum sensing，QS）是一种可被非合作骗子利用的社会特征。以前已经表明，通过将QS与公共和私人产品的生产联系起来，可以防止作弊行为侵入合作者群体，这被Dandekar等人（Science 2012;338：264266）描述为“合作的代谢激励”。我们假设铜绿假单胞菌可以进化出新的欺骗策略，通过重新连接其对两种QS信号（3 O-C12-HSL和C4-HSL）的组合响应来规避私人物品代谢。我们进行了一个选择实验，在公共和私人物品生长培养基之间循环铜绿假单胞菌，并进化出一种分离物，该分离物将其对协同蛋白酶表达的控制从协同（AND门）响应重新连接到双信号输入到仅3 O-C12-HSL响应。我们发现，这种隔离规避代谢激励合作，并作为一个组合的信号欺骗，具有更高的健身竞争与它的祖先。我们的研究结果显示了三个重要的原则：第一，组合QS允许出现不同的社会策略;第二，私人物品征收的限制不足以解释自然种群中合作的维持;第三，修改组合QS响应可能导致细菌种群中重要的生理结果。
In the opportunistic pathogen Pseudomonas aeruginosa, quorum sensing (QS) is a social trait that is exploitable by non-cooperating cheats. Previously it has been shown that by linking QS to the production of both public and private goods, cheats can be prevented from invading populations of cooperators and this was described by Dandekar et al. (Science 2012;338:264266) as 'a metabolic incentive to cooperate'. We hypothesized that P. aeruginosa could evolve novel cheating strategies to circumvent private goods metabolism by rewiring its combinatorial response to two QS signals (3O-C12-HSL and C4-HSL). We performed a selection experiment that cycled P. aeruginosa between public and private goods growth media and evolved an isolate that rewired its control of cooperative protease expression from a synergistic (AND-gate) response to dual-signal input to a 3O-C12-HSL-only response. We show that this isolate circumvents metabolic incentives to cooperate and acts as a combinatorial signalling cheat, with higher fitness in competition with its ancestor. Our results show three important principles: first, combinatorial QS allows for diverse social strategies to emerge; second, restrictions levied by private goods are not sufficient to explain the maintenance of cooperation in natural populations; and third, modifying combinatorial QS responses could result in important physiological outcomes in bacterial populations.