mcp, aer, cheB, and cheV contribute to the regulation of Vibrio alginolyticus (ND‐01) adhesion under gradients of environmental factors

Abstract

Adhesion is a key virulence factor of pathogens and can be affected by the environment. Our previously research with RNA‐seq indicated that mcp, aer, cheB, and cheV might play roles in the regulation of adhesion in Vibrio alginolyticus (ND‐01). In order to determine whether and how environmental factors affect adhesion through these genes, gene silencing was performed followed by quantitative real‐time PCR (qRT‐PCR), RNAi, transmission electron microscopy, and adhesion, capillary, and motility assays to verify how these genes influence adhesion. Silencing these genes led to deficiencies in adhesion, chemotaxis, flagellar assembly, and motility. The expression levels of cheA, cheW, and cheY, which are important genes closely related to the functions of mcp, aer, cheV, and cheB, were significantly downregulated in all of the RNAi groups. The expression of mcp, aer, cheV, and cheB under different gradients of temperature, pH, and salinity and after starvation for various durations was also detected, which showed that these genes were sensitive to certain environmental stresses, particularly pH and starvation. Our results indicated that mcp, aer, cheB, and cheV: (1) are necessary for ND‐01 adhesion; (2) play key roles in the bacterial chemotaxis pathway by controlling the expression of downstream genes; (3) might affect adhesion by impacting motility, though motility is not the only route through which adhesion is affected; and (4) contribute to the regulation of ND‐01 adhesion in natural environments with different temperatures, pH levels, and salinities as well as after various starvation periods.

The role of rpoS in the regulation of Vibrio alginolyticus virulence and the response to diverse stresses

“…The highly pathogenic V. alginolyticus ND‐01 was obtained from mariculture fish large yellow croaker (Yan et al., ) and cultured on Luria–Bertani (LB) agar or in LB broth containing 2% NaCl at 28°C (Huang et al., ).…”

“…In order to determine the effects of temperature, V. alginolyticus was grown at 4, 18, 28 and 37°C, respectively, in LB broth (Huang et al., ).…”

secA, secD, secF, yajC, and yidC contribute to the adhesion regulation of Vibrio alginolyticus

“…Host mucus is abundantly found on the surface of the skin, gills, and gut lining; therefore, it is the first site of interaction between the pathogen and its host (Yan, Zhao, Wang, Zou, & Chen, 2010). Several genes have been demonstrated to be involved into the bacterial adhesion to fish mucus (Qin, Yan, Su, Li, & Zou, 2013;Qin et al, 2014;Qin, Lin, Chen, Xu, & Yan, 2016;Huang, Hu, et al, 2016;Huang et al, 2017;Lin et al, 2017). Previous researches on other bacteria have also shown that some secretion systems are necessary for adhesion, mainly through regulating the secretion of adhesin.…”

“…Adhesion of pathogens to the surface of hosts is considered as an important initial step of infection process (Chen, Yan, Wang, Zhuang, & Wang, ). Although several genes have been demonstrated to be involved in the adhesion of V. alginolyticus (Huang et al., , Huang, Hu, et al, , ; Luo et al., ; Wang et al., ), the molecular mechanisms of V. alginolyticus adhesion still call for further investigation.…”

A metabolomic investigation into the temperature‐dependent virulence of Pseudomonas plecoglossicida from large yellow croaker (Pseudosciaena crocea)

“…A QuantStudio™ 6 Flex real‐time PCR system (ABI, USA) together with SYBR green I fluorescent dye (Dongsheng, Guangzhou, China) was used for qRT‐PCR analysis as described by Huang et al (). Primers designed with Primer Premier 5.0 were listed in Supporting Information Table S2.…”