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鞭毛是细菌的主要运动器官,也是一种重要的致病因子。趋化性是有运动能力的细菌趋向有益刺激,逃避有害刺激的反应。前期研究表明,缺乏趋化性核心基因che A的西瓜噬酸菌(Acidovorax citrulli)致病力下降;为明确鞭毛素基因和趋化性核心基因同时缺失对西瓜噬酸菌的影响以及趋化性与鞭毛基因间的关系,本研究构建了西瓜噬酸菌双缺失突变菌株ΔcheAΔfliC及其互补菌株ΔcheAΔfliC::che A::fliC、突变菌株ΔfliC及互补菌株ΔfliC::fliC,并对致病力与生物学特性进行测定。结果显示,双缺失突变菌株ΔcheAΔfliC致病力、运动能力、生长能力、种子粘附能力均显著降低,生物膜形成能力显著增强;与ΔfliC和ΔcheA单缺失突变株相比,双缺失突变菌株ΔcheAΔfliC致病力显著下降,生物膜形成能力显著提升,说明fliC和che A同时缺失对西瓜噬酸菌致病力和生物膜形成能力影响更为显著;三者运动能力基本保持一致,说明fliC缺失与che A缺失同样影响西瓜噬酸菌的运动能力,进一步说明了西瓜噬酸菌趋化性核心基因che A通过调控鞭毛的运动从而影响西瓜噬酸菌的运动能力。ΔfliC、ΔcheAΔfliC突变株种子上粘附能力显著下降,且均低于ΔcheA,说明鞭毛素基因fliC对西瓜噬酸菌粘附能力起着重要作用,这将对瓜类细菌性果斑病的防控和有效防治药剂的研制提供了基础。
Flagella are the main bacterial organs, but also an important virulence factor. Chemotaxis is a motor that has the potential to stimulate beneficial bacteria and evade harmful stimuli. Previous studies showed that the pathogenicity of Acidovorax citrulli, which lacked the chemoattractant core gene che A, was reduced. In order to clarify the effect of simultaneously deletion of the flagellin gene and the chemotactic core gene on the watermelon phage bacterium and chemotaxis And flagellar genes, this study constructed a double deletion mutant of watermelon phage ΔcheAΔfliC and its complementary strains ΔcheAΔfliC :: che A :: fliC, mutant strains ΔfliC and complementary strains ΔfliC :: fliC, and the virulence and Biological characteristics were measured. The results showed that the pathogenicity, exercise capacity, growth ability and seed adhesion capacity of double deletion mutant ΔcheAΔfliC were significantly decreased and the biofilm formation ability was significantly enhanced. Compared with ΔfliC and ΔcheA single deletion mutant, the double deletion mutant ΔcheAΔfliC Significantly reduced the ability to significantly reduce the biofilm formation ability, indicating that fliC and che A simultaneous deletion of pathogenicity and biofilm formation of watermelon acidophilus more significant impact; exercise capacity basically the same, indicating the lack of fliC and che A loss also affects the ability of watermelon phagocytosis motility, and further elucidates the watermelon phage chemotactic core gene che A by regulating the movement of flagella so as to affect watermelon acid bacteria motility. ΔfliC, ΔcheAΔfliC mutant seed adhesion decreased significantly, and were lower than ΔcheA, flagellin fliC gene on watermelon adhesion ability plays an important role, which will control the melon bacterial fruit spot And effective prevention and treatment of agents to provide the basis for the development.