A Mobile Quorum-Sensing System inSerratia marcescens

Abstract

Quorum-sensing systems that have been widely identified in bacteria play important roles in the regulation of bacterial multicellular behavior by which bacteria sense population density to control various biological functions, including virulence. One characteristic of the luxIR quorum-sensing genes is their diverse and discontinuous distribution among proteobacteria. Here we report that the spnIR quorum-sensing system identified in the enterobacterium Serratia marcescens strain SS-1 is carried in a transposon, TnTIR, which has common characteristics of Tn3 family transposons and is mobile between chromosomes and plasmids of different enterobacterial hosts. SpnIR functions in the new host and was shown to negatively regulate the TnTIR transposition frequency. This finding may help reveal the horizontal transfer and evolutionary mechanism of quorum-sensing genes and alter the way that we perceive regulation of bacterial multicellular behavior.

Microbial population dynamics and profiling of quorum sensing agents in membrane bioreactor

“…Almost all AHL producing strains were belonged to proteobacteria and to our knowledge, most of the LuxI/ R related QS genes have also been identified in this phylum. Therefore, the presence of QS regulation have already been confirmed by various studies in all isolates including Staphylococcus (Zhang et al, 2004), Serratia (Wei et al, 2006), Pseudomonas sp. (Juhas et al, 2005), Klebsiella (Balestrino et al, 2005), Psychrobacter (Jay et al, 2003) and Delftia sp.…”

Identification and Characterization of a Second Quorum-Sensing System in Agrobacterium tumefaciens A6

“…Using an approach described previously for Ti plasmid isolation (26), however, we failed to isolate the putative plasmid. One possible explanation for this failure is that this plasmid is too large to be isolated by routine methods, and the other possibility is that the QS2 system is carried not on a plasmid but in an integrative conjugative element, similar to the transmissible QS system in Serratia marcescens (46). It has been suggested that the multiple QS systems in most bacteria appear to have been acquired from separate sources (47,48).…”

N-Acylhomoserine lactone-dependent cell-to-cell communication and social behavior in the genus Serratia

“…Lateral gene transfer may conceivably play an important role in driving the transfer of quorum-sensing units between different bacterial species (Boucher et al, 2003;Lerat and Moran, 2004). Interestingly, we have discovered that in S. marcescens SS-1, the spnIR quorum-sensing genes are located within a novel Tn3 family transposon termed TnTIR (Wei et al, 2006). The position of spnIR within the transposon is therefore likely to enhance opportunities for horizontal transfer of quorum-sensing genes and so increase the frequency of gene acquisition and evolution within microbial genomes.…”