title: A novel two-component system BqsS-BqsR modulates quorum sensing-dependent biofilm decay in Pseudomonas aeruginosa.
abstract: Pseudomonas aeruginosa can grow either as planktonic- or biofilm-form in response to environmental changes. Recent studies show that switching from biofilm to planktonic lifestyle requires rhamnolipids. Here we report the identification of a novel twocomponent system BqsS-BqsR that regulates biofilm decay in P. aeruginosa. BqsS is a multidomain sensor kinase and BqsR is an OmpR-like response regulator. Deletion of either bqsS or bqsR in P. aeruginosa mPAO1 resulted in a significant increase in biofilm formation. Time course analysis showed that the bqsS-bqsR mutants were defective in biofilm dispersal and in rhamnolipid production. Mutation of the BqsS-BqsR two-component system did not affect the biosynthesis of long chain quorum sensing (QS) signal N-3-oxo-dodecanoyl-homoserine lactone (3OC12HSL) but resulted in reduced production of the short chain QS signal N-butyryl-L-homoserine lactone (C4HSL) and the Pseudomonas quinolone signal (PQS). Exogenous addition of C4HSL, PQS or rhamnolipids to the bqsS mutant reduced the biofilm formation to the wild-type level. Evidence suggests that the BqsS-BqsR two-component system might promote conversion of anthranilate to PQS. Taken together, these results establish BqsS-BqsR as a novel two-component system that regulates biofilm decay in P. aeruginosa by modulating biosynthesis of QS signals and rhamnolipids.
authors.affiliation: Institute of Molecular and Cell Biology; Singapore.
authors.forename: Yi-Hu
authors.initials: YH
authors.lastname: Dong
authors.forename: Xi-Fen
authors.initials: XF
authors.lastname: Zhang
authors.forename: Shu-Wen
authors.initials: SW
authors.lastname: An
authors.forename: Jin-Ling
authors.initials: JL
authors.lastname: Xu
authors.forename: Lian-Hui
authors.initials: LH
authors.lastname: Zhang