The sensor histidine kinase PhcS participates in the regulation of quorum sensing-dependent virulence genes in <i>Ralstonia pseudosolanacearum</i> strain OE1-1

The soil-borne <i>Ralstonia solanacearum</i> species complex (RSSC) infects more than 300 plant species in over 50 families, including solanaceous plants, causing the devastating wilt disease that substantially decreases agricultural production worldwide. The cell density-dependent gene regulation system, QS, is required for RSSC virulence and involves two signaling pathways for the induction and activation of PhcA, which is the master transcriptional regulator in QS. In the present study, we describe the contribution of sensor histidine kinase PhcS to the PhcA induction, along with the alternative sensor kinase PhcK, independently of the sensing of QS signal methyl 3-hydroxymyristate in a phylotype I strain of RSSC, <i>R. pseudosolanacearum</i> strain OE1-1. This study further expands our knowledge of multiple networks, suggesting that several PhcS-mediated two-component systems are likely necessary for RSSC QS and virulence.