Evolutionary Transition from Pathogenicity to Commensalism: Global Regulator Mutations Mediate Fitness Gains through Virulence Attenuation.

ABSTRACT: Symbiotic interactions are indispensable for metazoan function, but their origin and evolution remain elusive. We use a controlled evolution experiment to demonstrate the emergence of novel commensal interactions between Pseudomonas aeruginosa, an initially pathogenic bacterium, and a metazoan host, Caenorhabditis elegans. We show that commensalism evolves through loss of virulence, because it provides bacteria with a double fitness advantage: Increased within-host fitness and a larger host population to infect. Commensalism arises irrespective of host immune status, as the adaptive path in immunocompromised C. elegans knockouts does not differ from that in wild type. Dissection of temporal dynamics of genomic adaptation for 125 bacterial populations reveals highly parallel evolution of in

SUBMITTER: Jansen G 

PROVIDER: S-EPMC4651237 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature