Coordination of swarming motility, biosurfactant synthesis, and biofilm matrix exopolysaccharides production in Pseudomonas aeruginosa----中国科学院微生物研究所

科研成果

论文题目:	Coordination of swarming motility, biosurfactant synthesis, and biofilm matrix exopolysaccharides production in Pseudomonas aeruginosa
作者:	Wang Shiwei, Yu Shan, Zhang Zhenyin, Wei Qing, Yan Lu, Ai Guomin, Liu Hongsheng, Ma Luyan Z*
联系作者:	Ma Luyan Z*
刊物名称:	Appl Environ Microbiol
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年份:	2014
影响因子:	4.486
论文下载:	http://aem.asm.org/content/early/2014/08/25/AEM.01237-14.long
摘要:	Biofilm formation is a complex process with many factors involved. Bacterial swarming motility and exopolysaccharides both contribute to biofilm formation, yet it is unclear how bacteria coordinate the swarming motility and the production of exopolysaccharides. Psl and Pel are two key biofilm matrix exopolysaccharides in Pseudomonas aeruginosa. This opportunistic pathogen has three types of motilities including swimming, twitching, and swarming. Here we demonstrated that elevated Psl and/or Pel production reduced swarming motility of P. aeruginosa, but had little effect on swimming and twitching. The reduction was due to decreased rhamnolipids production with no relation to the transcription of rhlAB, two key genes involved in biosynthesis of rhamnolipids. Rhamnolipids negative mutants rhlR and rhlAB synthesized more Psl, whereas exopolysaccharide-deficient strains exhibited hyper-swarming phenotype. These results suggested that competition for common sugar precursors catalyzed by AlgC could be a tactic for P. aeruginosa to balance the synthesis of exopolysaccharides and rhamnolipids and to control bacterial motilities and biofilm formation inversely, because the biosynthesis of rhamnolipids, Psl, and Pel all requires AlgC to provide the sugar precursors and an additional algC enhances the biosynthesis of Psl and rhamnolipids. In addition, our data indicated that the increasing of RhlI/RhlR expression attenuated Psl production. This implied that the quorum sensing signals could regulate exopolysaccharides biosynthesis indirectly in bacterial communities. In summary, this study represents a mechanism that bacteria utilize to co-ordinate swarming motility, the synthesis of biosurfactant, and the production of biofilm matrix exopolysaccharides, which is critical for biofilm formation and bacterial survival in environment.