Experimental evolution of independent genetic pathways for resistance to Pseudomonas aeruginosa pathogenicity within the nematode Caenorhabditis remanei

Pathogenic host-microbe interactions can result from continuous evolution of a hosts ability to resist infection and a pathogens ability to survive and replicate. Pseudomonas aeruginosa is a versatile and opportunistic pathogen, ubiquitous in the environment, and capable of damaging plants, vertebrates, and invertebrates. Previous studies in nematodes suggest that the pathogenic effects of P. aeruginosa can result from multiple distinct pathways: a toxin-based effect that kills within a few hours and a generalized virulence that kills over the course of multiple days. Using experimental evolution in the highly polymorphic nematode Caenorhabditis remanei, we show that nematode resistance to the two modes of pathogenesis in P. aeruginosa evolves through genetically independent pathways. These results demonstrate that multiple virulence patterns in a pathogen can result in multiple responses in the host, and the genetic lines established here create resources for further exploration of the genetic basis for resistance to P. aeruginosa.