Detection of AI-2 receptors in genomes of Enterobacteriaceae suggests a role of type-2 quorum sensing in closed ecosystems.
The LuxS enzyme, an S-ribosyl-homocysteine lyase, catalyzes the production of the signal precursor for autoinducer-2 mediated quorum sensing (QS-2) in Vibrio. Its widespread occurrence among bacteria is often considered the evidence for a universal language for interspecies communication. Presence of the luxS gene and production of the autoinducer-2 (AI-2) signal have repeatedly been the only evidences presented to assign a functional QS-2 to the most diverse species. In fact, LuxS has a primary metabolic role as part of the activated methyl cycle. In this review we have analyzed the distribution of QS-2 related genes in Enterobacteriaceae by moving the focus of the investigation from AI-2 production to the detection of potential AI-2 receptors. The latter are common in pathogens or endosymbionts of animals, but were also found in a limited number of Enterobacteriaceae of the genera Enterobacter, Klebsiella, and Pantoea that live in close association with plants or fungi. Although a precise function of QS-2 in these species has not been identified, they all show an endophytic or endosymbiontic lifestyle that suggests a role of type-2 quorum sensing in the adaptation to closed ecosystems.
Plant Protection Division, Agroscope Changins-Wädenswil ACW, Schloss 1, Wädenswil CH-8820, Switzerland. fabio.rezzonico@acw.admin.ch
Fabio
F
Rezzonico
Theo H M
TH
Smits
Brion
B
Duffy
D017753:Ecosystem; D004755:Enterobacteriaceae / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D016680:Genome, Bacterial; D006714:Homoserine / Q000031:analogs & derivatives* / Q000378:metabolism; D007783:Lactones / Q000378:metabolism*; D053038:Quorum Sensing; D011956:Receptors, Cell Surface / Q000378:metabolism*
D007783:Lactones; C091088:N-octanoylhomoserine lactone; D011956:Receptors, Cell Surface; D006714:Homoserine