Two Homologous Agr-Like Quorum-Sensing Systems Cooperatively Control Adherence, Cell Morphology, and Cell Viability Properties in Lactobacillus plantarum WCFS1

Abstract

ABSTRACT A two-component regulatory system of Lactobacillus plantarum , encoded by genes designated lamK and lamR ( hpk10 and rrp10 ), was studied. The lamK and lamR genes encode proteins which are highly homologous to the quorum-sensing histidine kinase LamC and the response regulator LamA, respectively. Transcription analysis of the lamKR operon and the lamBDCA operon and liquid chromatography-mass spectrometry analysis of production of the LamD558 autoinducing peptide were performed for Δ lamA , Δ lamR , Δ lamA Δ lamR deletion mutants and a wild-type strain. The results suggested that lamA and lamR are cooperating genes. In addition, typical phenotypes of the Δ lamA mutant, such as reduced adherence to glass surfaces and filamentous cell morphology, were enhanced in the Δ lamA Δ lamR mutant. Microarray analysis suggested that the same cell wall polysaccharide synthesis genes, stress response-related genes, and cell wall protein-encoding genes were affected in the Δ lamA and Δ lamA Δ lamR mutants. However, the regulation ratio was more significant for the Δ lamA Δ lamR mutant, indicating the cooperative effect of LamA and LamR.