ZntR调控副溶血弧菌锌稳态、氧化应激抗性和毒力

ZntR modulates zinc homeostasis, oxidative stress resistance, and virulence of Vibrio parahaemolyticus

摘要:

【目的】 探究金属调节因子ZntR对副溶血弧菌金属稳态的调控作用，明确其对细菌氧化应激抗性和毒力的影响。【方法】 采用生长曲线分析和菌体内金属含量测定方法，探究ZntR对副溶血弧菌金属稳态的调控作用；通过生长曲线分析探究ZntR对副溶血弧菌氧化应激抗性的影响；利用斑马鱼竞争感染试验评估ZntR对副溶血弧菌毒力的影响；通过转录组测序鉴定ZntR调控的基因。【结果】 zntR基因缺失株(ΔzntR)在锌、镍过量和铁限制条件下表现出生长缺陷，其生长缺陷均与锌稳态紊乱有关；在ΔzntR中超表达zntA促进其在锌、镍过量和铁限制条件下的生长；在锌过量的情况下，ΔzntR对H₂O₂诱导氧化应激的抗性减弱；在斑马鱼竞争感染试验中，ΔzntR的毒力下降；转录组测序结果显示，ZntR调控一些毒力相关基因的表达。【结论】 ZntR调控副溶血弧菌锌稳态，并促进细菌氧化应激抗性和毒力。

Abstract:

[Objective] To explore the regulatory role of the metalloregulator ZntR in metal homeostasis and clarify the effects of ZntR on the oxidative stress resistance and virulence of Vibrio parahemolyticus. [Methods] Growth curve analysis and intracellular metal content quantification were performed to investigate the regulatory effect of ZntR on the metal homeostasis in V. parahaemolyticus. The effects of ZntR on the oxidative stress resistance and virulence of V. parahaemolyticus were explored by the growth curve analysis and the competitive infection assay in the zebrafish model, respectively. The genes regulated by ZntR were identified by RNA sequencing. [Results] The zntR-deleted strain (ΔzntR) exhibited growth defects under zinc, nickel excess and iron restriction conditions, and the growth defects were related to zinc homeostasis disturbance. The overexpression of zntA in ΔzntR promoted the growth under zinc, nickel excess and iron restriction conditions. In the case of zinc excess, ΔzntR demonstrated weakened resistance to H₂O₂-induced oxidative stress. The virulence of ΔzntR was attenuated in a competitive infection assay in the zebrafish model. RNA sequencing revealed that ZntR regulated the expression of several virulence genes. [Conclusion] ZntR modulates zinc homeostasis and improves oxidative stress resistance and virulence of V. parahaemolyticus.