show Abstracthide AbstractThe coordination of group behaviors in bacteria is achieved by cell-cell signaling process called quorum sensing (QS). QS is a cell- to- cell communication system, which synchronously control expression of vast range of genes in response to changes in cell density and is mediated by autoinducers such as acyl homoserine lactone that act as extracellular signals. Aliivibrio salmonicida the causative agent of cold-water vibrosis in marine aquacultures at temperatures below 10°C uses QS to regulate several activities such as motility, biofilm formation, adhesion and colony morphology. Although little is known about the genes and the detailed mechanisms involved in the regulation of these phenotypes. In the present study, the transcripts of ?litR and ?rpoQ mutants were sequenced and compared to the lysogenic A. salmonicida wild-type LFI1238 at low temperature and two cell densities (LCD and HCD), in order to identify the major differences in the gene expression profiles associated with the modulation of the QS related phenotypes by LitR and RpoQ.