文献类型：期刊文献

英文题名：Alternative Sigma Factor RpoX Is a Part of the RpoE Regulon and Plays Distinct Roles in Stress Responses, Motility, Biofilm Formation, and Hemolytic Activities in the Marine Pathogen Vibrio alginolyticus

作者：Gu, Dan[1,3];Zhang, Jun[1];Hao, Yuan[1];Xu, Rongjing[4];Zhang, Yuanxing[1,2];Ma, Yue[1,2];Wang, Qiyao[1,2]

机构：[1]East China Univ Sci & Technol, State Key Lab Bioreactor Engn, Shanghai, Peoples R China;[2]Shanghai Engn Res Ctr Maricultured Anim Vaccines, Shanghai, Peoples R China;[3]Yangzhou Univ, Jiangsu Coinnovat Ctr Prevent & Control Important, Jiangsu Key Lab Zoonosis, Yangzhou, Jiangsu, Peoples R China;[4]Yantai Tianyuan Aquat Co & Td, Yantai, Shandong, Peoples R China

年份：2019

卷号：85

期号：14

起止页码：1

外文期刊名：APPLIED AND ENVIRONMENTAL MICROBIOLOGY

收录：;EI(收录号：20210509844613);WOS:【SCI-EXPANDED(收录号:WOS:000476468600002)】；

基金：This work was supported by grants from the National Natural Science Foundation of China (no. 31772893 to Y.M. and 31772891 to Q.W.), the Ministry of Agriculture of China (CARS-47-G17), and the Science and Technology Commission of Shandong and Shanghai Municipality (2017CXGC0103 and 17391902000).

语种：英文

外文关键词：ChIP-seq; RNA-seq; RpoE; RpoX; Vibrio alginolyticus; virulence

摘要：Vibrio alginolyticus is one of the most abundant microorganisms in marine environments and is also an opportunistic pathogen mediating high-mortality vibriosis in marine animals. Alternative sigma factors play essential roles in bacterial pathogens in the adaptation to environmental changes during infection and the adaptation to various niches, but little is known about them for V. alginolyticus. Our previous investigation indicated that the transcript level of the gene rpoX significantly decreased in an RpoE mutant. Here, we found that rpoX was highly expressed in response to high temperature and low osmotic stress and was under the direct control of the alternative sigma factor RpoE and its own product RpoX. Moreover, transcriptome sequencing (RNA-seq) results showed that RpoE and RpoX had different regulons, although they coregulated 105 genes at high temperature (42 degrees C), including genes associated with biofilm formation, motility, virulence, regulatory factors, and the stress response. RNA-seq and chromatin immunoprecipitation sequencing (ChIP-seq) analyses as well as electrophoretic mobility shift assays (EMSAs) revealed the distinct binding motifs of RpoE and RpoX proteins. Furthermore, quantitative real-time reverse transcription-PCR (qRT-PCR) analysis also confirmed that RpoX can upregulate genes associated with flagella, biofilm formation, and hemolytic activities at higher temperatures. rpoX abrogation does not appear to attenuate virulence toward model fish at normal temperature. Collectively, data from this study demonstrated the regulatory cascades of RpoE and an alternative sigma factor, RpoX, in response to heat and osmotic stresses and their distinct and overlapping roles in pathogenesis and stress responses in the marine bacterium V. alginolyticus. IMPORTANCE The alternative sigma factor RpoE is essential for the virulence of Vibrio alginolyticus toward marine fish, coral, and other animals in response to sea surface temperature increases. In this study, we characterized another alternative sigma factor, RpoX, which is induced at high temperatures and under low-osmoticstress conditions. The expression of rpoX is under the tight control of RpoE and RpoX. Although RpoE and RpoX coregulate 105 genes, they are programming different regulatory functions in stress responses and virulence in V. alginolyticus. These findings illuminated the RpoE-RpoX-centered regulatory cascades and their distinct and overlapping regulatory roles in V. alginolyticus, which facilitates unraveling of the mechanisms by which the bacterium causes diseases in various sea animals in response to temperature fluctuations as well as the development of appropriate strategies to tackle infections by this bacterium.