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

摘要:

[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∆motA，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。

Abstract:

[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] ∆motA 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 and ∆motA mutant. [Results] ∆motA 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.