Conditional privatization of a public siderophore enables Pseudomonas aeruginosa to resist cheater invasion
Understanding the mechanisms that promote cooperative behaviors of bacteria in their hosts is of great significance to clinical therapies. Environmental stress is generally believed to increase competition and reduce cooperation in bacteria. Here, we show that bacterial cooperation can in fact be maintained because of environmental stress. We show that Pseudomonas aeruginosa regulates the secretion of iron scavenging siderophores in the presence of different environmental stresses, reserving this public good for private use in protection against reactive oxygen species when under stress. We term this strategy "conditional privatization" Using a combination of experimental evolution and theoretical modeling, we demonstrate that in the presence of environmental stress the conditional privatization strategy is resistant to invasion by non producing cheaters. These findings show how the regulation of public goods secretion under stress affects the evolutionary stability of cooperation in a pathogenic population, which may assist in the rational development of novel therapies.Pyoverdine is secreted by the opportunistic pathogen Pseudomonas aeruginosa to scavenge iron from its hosts. Here, the authors show that under stress conditions P. aeruginosa uses a 'conditional privatization' strategy, reserving pyoverdine intracellularly to protect against oxidative damage.
Nature Communications