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Quorum sensing positively regulates flagellar motility in pathogenic V ibrio harveyi
Author(s) -
Yang Qian,
Defoirdt Tom
Publication year - 2015
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12420
Subject(s) - quorum sensing , biology , virulence , motility , mutant , autoinducer , microbiology and biotechnology , vibrio harveyi , gene , bacteria , genetics , vibrio
Summary V ibrios belonging to the H arveyi clade are among the major pathogens of aquatic organisms. Quorum sensing ( QS ) is essential for virulence of V . harveyi towards different hosts. However, most virulence factors reported to be controlled by QS to date are negatively regulated by QS , therefore suggesting that their impact on virulence is limited. In this study, we report that QS positively regulates flagellar motility. We found that autoinducer synthase mutants showed significantly lower swimming motility than the wild type, and the swimming motility could be restored by adding synthetic signal molecules. Further, motility of a luxO mutant with inactive QS ( LuxO D47E ) was significantly lower than that of the wild type and of a luxO mutant with constitutively maximal QS activity ( LuxO D47A ). Furthermore, we found that the expression of flagellar genes (both early, middle and late genes) was significantly lower in the luxO mutant with inactive QS when compared with wild type and the luxO mutant with maximal QS activity. Motility assays and gene expression also revealed the involvement of the quorum‐sensing master regulator LuxR in the QS regulation of motility. Finally, the motility inhibitor phenamil significantly decreased the virulence of V . harveyi towards gnotobiotic brine shrimp larvae.