Role and activation of type III secretion system genes in Pseudomonas aeruginosa-induced Drosophila killing.

Pseudomonas aeruginosa strains PAO1 and CHA showing type III system-dependent cytotoxicity towards macrophages ex vivo are able to induce rapid death of adult fly Drosophila melanogaster accompanied by bacterial multiplication to high-titers. The role of P. aeruginosa type III secretion system in rapid fly killing was demonstrated here by using several isogenic CHA mutants, selectively affected in this system. The activation of P. aeruginosa pexsCBA, the regulatory operon of the type III system, and the activation of the Drosophila gene diptericin, showed the host-pathogen recognition during infection process.