sigW与rsiW失活对沙福芽孢杆菌ST7耐锰能力的影响

Deletion of sigW and rsiW affects the manganese tolerance of Bacillus safensis ST7

摘要:

【背景】 前期转录组学研究提示RNA聚合酶σ因子W (sigma factor W, SigW)和反σ因子W (anti-sigma factor W, RsiW)可能参与沙福芽孢杆菌(Bacillus safensis)锰胁迫应激途径。【目的】 研究sigW和rsiW基因缺失对沙福芽孢杆菌ST7的运动能力、生物膜形成能力和锰氧化能力的影响。【方法】 以沙福芽孢杆菌ST7为研究对象，使用同源重组敲除技术构建沙福芽孢杆菌ST7的sigW和rsiW缺失突变株，检测野生株与突变株在运动能力、生物膜形成能力和锰氧化能力方面的差异，比较鞭毛形成相关基因的表达变化。【结果】 在非锰胁迫培养条件下sigW和rsiW基因缺失对ST7突变株的生长无明显影响；锰胁迫培养条件下sigW和rsiW基因缺失迟滞突变株的生长。相较于野生株，sigW突变株的运动能力和锰氧化能力减弱，生物膜形成能力增强；rsiW突变株的运动能力减弱，生物膜形成能力和锰氧化能力增强。并且sigW和rsiW突变株中与鞭毛合成相关基因flim、flgd、flii的表达量下降。【结论】 sigW和rsiW基因可促进沙福芽孢杆菌的鞭毛合成和运动能力，促进细菌的生长，共同调控菌株的锰氧化能力。

关键词:沙福芽孢杆菌;sigW和rsiW基因敲除;鞭毛;运动性;生物膜;锰氧化

Abstract:

[Background] Previous transcriptomics studies suggested that the RNA polymerase sigma factor (sigW) and the anti-sigma factor W (rsiW) might be involved in the manganese stress response of Bacillus safensis. [Objective] To investigate the effects of sigW and rsiW deletion on the motility, biofilm formation, and manganese-oxidizing ability of B.safensis ST7. [Methods] We employed homologous recombination to construct the sigW- and rsiW-deleted mutant strains of B.safensis ST7. Furthermore, we compared the motility, biofilm formation, manganese oxidation, and expression of flagellum formation-related genes between the wild type and the mutant strains. [Results] The deletion of sigW and rsiW had no significant effect on the growth of ST7 cultured without manganese stress, whereas it retarded the growth of ST7 under manganese stress. Compared with the wild type, ∆sigW showed reduced motility and manganese-oxidizing ability and enhanced biofilm formation, while ∆rsiW showed reduced motility and enhanced biofilm formation and manganese-oxidizing ability. In addition, the expression levels of genes (flim, flgd and flii) related to flagellum formation were downregulated in ∆sigW and ∆rsiW. [Conclusion] sigW and rsiW can promote the flagellum formation, motility, and growth and co-regulate the manganese-oxidizing ability of B.safensis.

Key words:Bacillus safensis;deletion of sigW and rsiW;flagellum;motility;biofilm;manganese oxidation