Quorum Sensing Regulates the Transcription of Lateral Flagellar Genes in <i>Vibrio Parahaemolyticus</i>

Abstract

<b>Aim:</b> Investigation of the lateral flagellar (Laf) genes transcription by the quorum sensing (QS) regulators AphA and OpaR in <i>Vibrio parahaemolyticus</i>. <b>Materials & methods:</b> Regulation mechanisms were assessed by combined utilization of swarming motility assay, qPCR, LacZ fusion, EMSA and DNase I footprinting. <b>Results:</b> AphA and OpaR oppositely regulate swarming motility and Laf genes. At high cell density, OpaR bound to the regulatory regions of <i>motY-lafK-fliEFGHIJ</i>, <i>fliMNPQR-flhBA</i>, <i>fliDSTKLA-motAB</i> and <i>lafA</i> to repress their transcription. At low cell density, AphA indirectly activated their transcription. <b>Conclusion:</b> OpaR repression of swarming motility was via its direct repression of Laf genes, while AphA exerted its regulatory effect on swarming motility through unknown regulator(s).