Analysis of the hierarchy of quorum-sensing regulation in Pseudomonas aeruginosa.

Quorum-sensing in Pseudomonas aeruginosa is known to regulate several aspects of pathogenesis, including virulence factor production, biofilm development, and antimicrobial resistance. Recent high-throughput analysis has revealed the existence of several layers of regulation within the QS-circuit. To address this complexity, mutations in genes encoding known or putative transcriptional regulators that were also identified as being regulated by the las and/or rhl QS systems were screened for their contribution in mediating several phenotypes, for example motility, secreted virulence products, and pathogenic capacity in a lettuce leaf model. These studies have further elucidated the potential contribution to virulence of these genes within the QS regulon.