茎瘤固氮根瘤菌ORS571中motA基因的功能分析

Functional analysis of motA gene in Azorhizobium caulinodans ORS571

【目的】MotA是细菌的鞭毛马达蛋白,是跨膜质子通道的重要组成结构之一,在调控鞭毛运动中具有至关重要的作用。本研究探究了Azorhizobium caulinodans ORS571中鞭毛马达基因motA对菌株表型和植物互作的影响。【方法】通过同源重组原理和三亲接合转移方法构建突变菌株ΔmotA,测定野生型与突变体在菌体生长、运动、固氮、胞外多糖合成、生物膜形成及根系定殖能力的差异。【结果】与野生型相比,突变体菌体生长没有明显差异,但其运动能力完全丧失,固氮、胞外多糖合成、生物膜形成及根系定殖能力减弱。【结论】MotA鞭毛马达蛋白对A.caulinodans ORS571的运动、固氮、胞外多糖合成、生物膜形成及根系定殖能力均有调控作用。

[Objective]MotA,an important flagellar motor protein regulating flagellar motility,is one of components of transmembrane proton channel.In this study,we explored the role of motA in Azorhizobium caulinodans ORS571 in the free-living and symbiotic states.[Methods]ΔmotA mutant was constructed by homologous recombination and tri-parental conjugation.We tested the characterizations of the growth state,swimming motility,nitrogen fixation,exopolysaccharides(EPS)production,biofilm formation,and host colonization between wild-type andΔmotA mutant.[Results]ΔmotA mutant showed defective cell motility ability but the growth property was not impaired,and its nitrogen fixation,EPS production,biofilm formation,and host colonization were lower than that of the wild-type.[Conclusion]In A.caulinodans ORS571,MotA plays role in motility,nitrogen fixation,EPS production,biofilm formation,and root colonization.