Mridha S and Kümmerli R (2022) Enforced specialization fosters mutual cheating and not division of labour in the bacterium Pseudomonas aeruginosa

A common way for bacteria to cooperate is via the secretion of beneficial public goods (proteases, siderophores, biosurfactants) that can be shared among individuals in a group. Bacteria often simultaneously deploy multiple public goods with complementary functions. This raises the question whether natural selection could favour division of labour where subpopulations or species specialise in the production of a single public good, whilst sharing the complementary goods at the group level. Here we use an experimental system, where we mix engineered specialists of the bacterium Pseudomonas aeruginosa that can each only produce one of the two siderophores, pyochelin or pyoverdine, and explore the conditions under which specialization can lead to division of labour. When growing pyochelin and pyoverdine specialists at different mixing ratios under different levels of iron limitation, we found that specialists could only successfully complement each other in environments with moderate iron ...

细菌群体协作的常见方式之一，是分泌可在个体间共享的有益公共物品（public goods），包括蛋白酶（proteases）、铁载体（siderophores）与生物表面活性剂（biosurfactants）。细菌往往会同时产生多种功能互补的公共物品。这一现象引出了一个科学问题：自然选择是否会青睐劳动分工模式，即亚种群或物种特化生产单一公共物品，同时在群体层面共享功能互补的公共产物？本研究采用实验体系，将仅能合成两种铁载体之一的工程化铜绿假单胞菌（Pseudomonas aeruginosa）特化株进行混合，探究特化作用促成劳动分工的具体条件。我们在不同铁限制水平下，以不同混合比例培养吡咯菌素（pyochelin）与绿脓菌素（pyoverdine）特化株，结果发现，特化株仅能在中等铁浓度的环境中实现成功的相互互补……