The CpxR-regulated periplasmic protease DegP coordinates the environmental stress adaptation, motility, and virulence in Edwardsiella piscicida

文献类型： 外文期刊

第一作者： Li, Hui

作者： Li, Hui;Ma, Xiang;Li, Hui;Fang, Qingjian;Zhang, Shanshan;Hu, Yonghua;Gu, Hanjie;Li, Hui;Fang, Qingjian;Zhang, Shanshan;Hu, Yonghua;Gu, Hanjie;Wang, Yan;Hu, Yonghua;Wang, Yan;Hu, Yonghua;Gu, Hanjie;Hu, Yonghua;Sui, Zhihai

作者机构：

关键词： Edwardsiella piscicida; DegP; Stress resistance; Motility; Virulence

期刊名称：MICROBIAL PATHOGENESIS （ 影响因子：3.5； 五年影响因子：3.6 ）

ISSN： 0882-4010

年卷期： 2025 年 207 卷

页码：

收录情况： SCI

摘要： Edwardsiella piscicida is a serious aquatic pathogen that infects a diverse spectrum of economically valuable fish species, inflicting substantial economic damage on the aquaculture industry. DegP, a periplasmic protein endowed with dual chaperone-protease activity, is vital for bacteria to preserve homeostasis and acclimate to environmental stresses. Nevertheless, studies about DegP in E. piscicida have been relatively limited. In this study, we determined that the DegP of E. piscicida shared high sequence identity with DegP proteins from diverse bacterial species and comprised conserved functional domains. The azocasein hydrolysis assays showed that the recombinant protein rDegP exhibited significant proteolytic activity in a substrate concentration-dependent manner with the optimal enzyme activity at 48 degrees C and pH 9.0. To probe the impact of DegP on stress adaptation and virulence, we constructed an in-frame deletion strain, TH1zdegP, through homologous recombination. Under normal conditions, TH1zdegP exhibited no discernible growth defects. However, TH1zdegP caused the significantly decreased survival in various forms of adversity including high temperature, alkalinity, acidity, oxidation stress, and high osmolarity. Additionally, TH1zdegP impaired the motility, but had no effect on biofilm formation and cell membrane integrity. Pathogenicity assays revealed that TH1zdegP significantly reduced adhesion to FG cells and impaired intracellular proliferation in RAW264.7 macrophages in vitro. Moreover, TH1zdegP displayed decreased resistance to tilapia serum, diminished capacity for tissue colonization, and attenuated overall virulence towards tilapia. The complementary strain TH1zdegPC successfully restored all the lost capabilities of TH1zdegP. To clarify the regulatory mechanism of DegP, the EMSA, (3-galactosidase detection and qRT-PCR demonstrated that the Cpx envelope stress system regulated the expression of degP through direct binding of CpxR to the degP promoter. These findings underscore that DegP, a protease regulated by the Cpx system, is indispensable for the adaptation to environmental stresses and virulence in E. piscicida. This study provides a comprehensive elucidation of the multifaceted roles of DegP and enhances our comprehension of its contributions to stress tolerance and pathogenicity in E. piscicida.

分类号：

  • 相关文献
作者其他论文 更多>>

微信小程序