A solo luxI-type gene directs acylhomoserine lactone synthesis and contributes to motility control in the marine sponge symbiont Ruegeria sp. KLH11

• Published in: Microbiology (Society for General Microbiology) Vol. 161; no. Pt 1; pp. 50 - 56
• Main Authors: Zan, Jindong, Choi, Okhee, Meharena, Hiruy, Uhlson, Charis L, Churchill, Mair E A, Hill, Russell T, Fuqua, Clay
• Format: Journal Article
• Language: English
• Published: England Society for General Microbiology 01-01-2015
• Subjects: Acyl-Butyrolactones - metabolism; Animals; Bacterial Proteins - genetics; Cell and Molecular Biology of Microbes; Gene Expression Regulation, Bacterial; Gene Order; Genetic Loci; Mutation; Porifera - microbiology; Rhodobacteraceae - genetics; Rhodobacteraceae - metabolism; Symbiosis; Transcription Factors - genetics
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.083956-0

Marine sponges harbour abundant and diverse bacterial communities, providing an ideal environment for bacterial cell-density-dependent cell-cell signalling, termed quorum sensing. The marine sponge symbiont Ruegeria sp. KLH11 produces mainly long chain acylhomoserine lactones (AHLs) and has been developed as a quorum sensing model for roseobacterial sponge symbionts. Two pairs of luxR/I homologues were identified by genetic screening and were designated ssaRI and ssbRI (sponge-associated symbiont locus A or B, luxR/luxI homologue). In this study, we identified a third luxI-type gene, named sscI. The sscI gene does not have a cognate luxR homologue present at an adjacent locus and thus sscI is an AHL synthase solo. The sscI gene is required for production of long-chain hydroxylated AHLs, contributes to AHL pools and modestly influences flagellar motility in KLH11. A triple mutant for all luxI-type genes cannot produce AHLs, but still synthesizes para-coumaroyl-homoserine lactone.