胡萝卜软腐果胶杆菌鞭毛钩基因flgK 的功能

【目的】为了研究鞭毛钩基因flgK在胡萝卜软腐果胶杆菌胡萝卜亚种(Pectobacterium carotovorum subsp.carotovorum,P.c.c)的功能。【方法】本研究采用两亲同源交换法构建了基因缺失突变体ΔflgKpcc并构建了互补菌株ΔflgKpcc-KH,测定突变体及其互补菌株的菌体形态、运动性、致病因子、致病性等表型。【结果】与野生菌株PccS1相比,ΔflgKpcc鞭毛缺失,菌体易沉降,在0.3%半固体培养基上运动能力明显降低,生长速率无明显变化,但是纤维素酶和蛋白酶的活性、生物膜形成能力明显下降,对感病寄主的致病力显著减弱。基因互补可以使上述突变表型恢复。【结论】实验表明,鞭毛基因flgK突变导致了菌体的运动性降低、病原菌毒性相关的酶活力下降,从而导致致病力下降。

Function of flgK gene in Pectobacterium carotovorum subsp. carotovorum

Objective] To investigate functions of flgKpcc gene in Pectobacterium carotovorum subsp.carotovorum(P.c.c).Methods] The gene knock-out mutant ΔflgKpcc and complemented strain ΔflgKpcc-KH were generated by biparental mating and their phenotypes including cell morphology,motility,pathogenic factors,and pathogenicity were investigated.Results] Non-flagellum,cell precipitation in the culture and significantly attenuated motility on 0.3% semisolid medium were observed in ΔflgKpcc compared to Pectobacterium carotovorum subsp.carotovorum S1.In addition,significant decrease in cellulase and protease activity,biofilm formation,and pathogenicity on host plant were found in ΔflgKpcc.While there were no apparent difference in growth rate in vitro,ΔflgKpcc-KH,the complementation strain,restored the phenotype of ΔflgKpcc to the wild type level.Conclusion] The gen of flgKpcc not only influences the cell motility,but also pathogenic factors to lead to the decreased pathogenicity in Pectobacterium carotovorum subsp.Carotovorum.