Genome analysis leads to discovery of Quorum Sensing Genes in Cedecea neteri

We have identified a strain of C. neteri SSMD04 isolated from pickled mackerel sashimi that produced N-acyl-homoserine lactone (AHL) type quorum sensing (QS) activity. Tandem mass sspectrometry revealed that C. neteri SSMD04 produced N-butyryl-homoserine lactone (C4-HSL). We identified a pair of luxIR homologues in this genome that shares the highest similarity with croIR from Citrobacter rodentium. The AHL synthase, which we named it as cneI (636 bp) and at 8bp distance from cneI is a sequence encoding a hypothetical protein, potentially the cognate receptor, a luxR homologue which we named it as cneR. We also found an orphan luxR in this isolate. To our knowledge, this is the first report on the AHL production activity in C. neteri, discovery of its luxI/R homologues and the orphan receptor.