title: Characterization of a new quorum sensing regulator luxT and its roles in the extracellular protease production, motility, and virulence in fish pathogen Vibrio alginolyticus.
abstract: Vibrio alginolyticus, an opportunistic pathogen that causes vibriosis in miscellaneous fish species, has brought about serious economic damage to the mariculture industry in South China. The mechanism of virulence regulation in V. alginolyticus is yet not known except a Vibrio harveyi-like quorum sensing (QS) system that is established to manipulate the expression of diverse genes including those encoding virulence determinants. In this study, a new TetR family QS regulator, luxT, was identified and characterized in V. alginolyticus. The transcription of luxT gene was cell density dependent and was positively regulated by LuxU, an established QS component relaying the signal from three paralleled QS regulatory systems in V. harveyi. In addition, luxT positively regulated both luxO at transcriptional level and luxR at post-transcriptional level, which is thoroughly different from the established QS regulation mode in V. harveyi and Vibrio vulnificus. The mutant of luxT deletion produced markedly decreased total extracellular proteases and reduced motility ability compared to the wild type and the complemented strain luxT                         (+). The fish infection results indicated that mutation of luxT led to marginal attenuation in the virulence of V. alginolyticus, suggesting that LuxT might play a role in the fine-tuning of the virulence via QS in V. alginolyticus.
authors: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
authors: Huan
authors: H
authors: Liu
authors: Dan
authors: D
authors: Gu
authors: Xiaodan
authors: X
authors: Cao
authors: Qin
authors: Q
authors: Liu
authors: Qiyao
authors: Q
authors: Wang
authors: Yuanxing
authors: Y
authors: Zhang
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D005393:Fish Diseases / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000378:metabolism*; D053038:Quorum Sensing / Q000235:genetics*; D017384:Sequence Deletion; D014158:Transcription, Genetic; D014735:Vibrio Infections / Q000382:microbiology / Q000662:veterinary; D044149:Vibrio alginolyticus / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology; D014774:Virulence / Q000235:genetics; D015027:Zebrafish / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D010447:Peptide Hydrolases