wbnH2基因对北京欧文氏菌生物学特性及致病力的影响

Effects of wbnH2 on biological characteristics and pathogenicity of Erwinia beijingensis

摘要:

【背景】北京欧文氏菌(Erwinia beijingensis)引起的刺芹侧耳细菌性软腐病(bacterial soft rot)给企业带来了严重的经济损失。wbnH2糖基转移酶基因在北京欧文氏菌中的生物学功能尚不明确。【目的】构建wbnH2基因的缺失株Δ-wbnH2和回补株C-wbnH2，探究wbnH2基因对北京欧文氏菌致病性的影响。【方法】采用同源重组方法构建北京欧文氏菌LMG 27579^TwbnH2基因缺失突变株Δ-wbnH2，并对基因缺失菌株的致病性、生长速度、运动能力、生物膜形成能力、黏附能力等生物学特性与野生型菌株进行比较分析；采用广宿主质粒pBBR1MCS2构建回补株C-wbnH2，排除了极性效应引起的突变株表型变化。【结果】与野生型菌株相比，基因缺失株Δ-wbnH2的生长速度无明显差别。但是wbnH2基因的缺失导致多糖分泌、生物膜形成能力、黏附能力、致病能力明显下降。【结论】wbnH2基因影响北京欧文氏菌多糖分泌、生物膜的形成能力、黏附能力及致病力，表明该基因在北京欧文氏菌致病过程中起重要作用，本研究为软腐病的防控提供了理论基础。

Abstract:

[Background] Bacterial soft rot caused by Erwinia beijingensis results in serious economic losses to enterprises. The biological function of the glycosyltransferase gene wbnH2 in E. beijingensis remains unclear. [Objective] To explore the effect of wbnH2 gene on the pathogenicity of E. beijingensis. [Methods] Homologous recombination was employed to construct the E. beijingensis LMG 27579^T wbnH2 -deleted mutant Δ -wbnH2. The biological characteristics such as pathogenicity, growth rate, motility, biofilm formation, and adhesion of Δ -wbnH2 were studied. Further, we used the broad-host-range plasmid pBBR1MCS2 to construct the complementation strain C -wbnH2 for excluding the polarity effect-caused phenotypic change of the mutant. [Results] Compared with that of the wild type, the growth rate of Δ -wbnH2 had no significant change. However, the deletion of wbnH2 resulted in significant decreases in polysaccharide secretion, biofilm formation, adhesion and pathogenicity. [Conclusion] The glycosyltransferase gene wbnH2 affects the polysaccharide secretion, biofilm formation, adhesion, and pathogenicity of E. beijingensis, playing a role in the pathogenic process. This study provides a theoretical basis for the prevention and control of bacterial soft rot.