Social evolution of toxic metal bioremediation in Pseudomonas aeruginosa.

Bacteria are often iron-limited, and hence produce extracellular iron-scavenging siderophores. A crucial feature of siderophore production is that it can be an altruistic behaviour (individually costly but benefitting neighbouring cells), thus siderophore producers can be invaded by non-producing social ‘cheats’. Recent studies have shown that siderophores can also bind other heavy metals (such as Cu and Zn), but in this case siderophore chelation actually reduces metal uptake by bacteria. These complexes reduce heavy metal toxicity, hence siderophore production may contribute to toxic metal bioremediation. Here, we show that siderophore production in the context of bioremediation is also an altruistic trait and can be exploited by cheating phenotypes in the opportunistic pathogen Pseudomonas aeruginosa. Specifically, we show that in toxic copper concentrations (i) siderophore non-producers evolve de novo and reach high frequencies, and (ii) producing strains are fitter than isogenic no...

细菌常处于铁限制状态，因此会产生胞外铁螯合铁载体。铁载体产生的一个关键特征是其可表现为利他行为（对个体而言代价高昂，但对邻近细胞有益），故而铁载体产生菌可能被不产生铁载体的社会性‘欺骗者’入侵。近期研究表明，铁载体还可结合其他重金属（如铜和锌），但在此情况下，铁载体螯合作用实际上会减少细菌对金属的摄取。这些复合物能降低重金属毒性，因此铁载体的产生可能有助于有毒金属的生物修复。本文中，我们发现铁载体产生在生物修复场景下同样是一种利他性状，且可能被机会致病菌铜绿假单胞菌中的欺骗表型所利用。具体而言，我们发现，在有毒铜浓度下：（i）铁载体非产生菌可从头进化并达到高频率；（ii）产生菌株的适应性优于同基因的非...