Evolution of PqsE as a <i>Pseudomonas aeruginosa</i> -specific regulator of LuxR-type receptors: insights from <i>Pseudomonas</i> and <i>Burkholderia</i>

<i>Pseudomonas aeruginosa</i>, a major pathogen for patients with cystic fibrosis and a primary constituent of healthcare-associated infections, relies on a complex quorum-sensing (QS) network to coordinate virulence factor production. Central to this system is the interaction between two proteins, PqsE and RhlR, which drive gene expression essential for pathogenesis. Our study investigates the conservation of the PqsE-RhlR interaction across related bacterial species, revealing that PqsE in <i>Pseudomonas</i> can enhance RhlR activity, while orthologs in <i>Burkholderia</i> lack this capacity. These findings offer new insights into the specificity and evolution of QS mechanisms, highlighting the PqsE-RhlR interaction as a potentially selective target for treating <i>P. aeruginosa</i> infections.