Wang Jianan, Liu Jun, Zhao Yuqiang, Sun Minghui, Yu Guixu, Fan Jiaqin, Tian Yanli, Hu Baishi
College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing, China.
Institute of Plant Protection and Soil Fertilizer, Hubei Academy of Agricultural Sciences, Wuhan, China.
Front Microbiol. 2022 Sep 20;13:977281. doi: 10.3389/fmicb.2022.977281. eCollection 2022.
In many bacteria, OxyR acts as a transcriptional regulator that facilitates infection degrading hydrogen peroxide (HO) generated by the host defense response. Previous studies showed that OxyR also plays an important role in regulating biofilm formation, cell motility, pili relate-genes expression, and surface polysaccharide production. However, the role of OxyR has not been determined in strain xjl12. In the current study, the qRT-PCR and western blot assays revealed that the expression level of was significantly induced by HO. The deletion mutant of was significantly impaired bacterial tolerance to oxidative stress and reduced catalase (CAT) activity. In addition, mutant resulted in reduced swimming motility, twitching motility, biofilm formation, virulence, and bacterial growth in by significantly affecting flagellin and type IV pili-related gene ( and ) expression. The qRT-PCR assays and western blot revealed that OxyR positively regulated the expression of and Furthermore, bacterial one-hybrid assay demonstrated that OxyR directly affected and promoter. Through bacterial two-hybrid assay, it was found that OxyR can directly interact with PilA and FliC. These results suggest that OxyR plays a major role in the regulating of a variety of virulence traits, and provide a foundation for future research on the global effects of OxyR in .
在许多细菌中，OxyR作为一种转录调节因子，通过降解宿主防御反应产生的过氧化氢（H₂O₂）来促进感染。先前的研究表明，OxyR在调节生物膜形成、细胞运动性、菌毛相关基因表达和表面多糖产生方面也发挥着重要作用。然而，OxyR在xjl12菌株中的作用尚未确定。在本研究中，qRT-PCR和蛋白质免疫印迹分析表明，OxyR的表达水平受到H₂O₂的显著诱导。OxyR缺失突变体显著损害了细菌对氧化应激的耐受性，并降低了过氧化氢酶（CAT）活性。此外，OxyR突变体通过显著影响鞭毛蛋白和IV型菌毛相关基因（pilA和fliC）的表达，导致游动运动性、颤动运动性、生物膜形成、毒力和在宿主体内的细菌生长降低。qRT-PCR分析和蛋白质免疫印迹表明，OxyR正向调节pilA和fliC的表达。此外，细菌单杂交试验表明，OxyR直接影响pilA和fliC的启动子。通过细菌双杂交试验，发现OxyR可以直接与PilA和FliC相互作用。这些结果表明，OxyR在调节多种毒力特征中起主要作用，并为未来研究OxyR在xjl12中的全局效应提供了基础。
