十字花科黑腐病菌IV型分泌系统的诱导表达与抗逆功能分析

 细菌通过IV型分泌系统(Type IV Secretion System, T4SS)的接合系统、效应物转运系统和释放/吸收系统3个子家族进行DNA、蛋白质及毒素的分泌和转运。十字花科黑腐病菌(Xanthomonas campestris pv. campestris, Xcc)是一种重要的植物病原菌,也是研究植物病原细菌与植物相互作用机理的模式细菌之一。本研究通过检测Xcc 8004野生型菌株和T4SS突变体在不同条件下的生长、诱导情况及对过敏反应的影响发现:T4SS不影响在培养基中的生长,与野生型菌株相比,T4SS突变体在非寄主辣椒ECW-10R上的过敏反应减弱;T4SS相关基因受基本培养基MMX诱导表达,且与Ni²⁺、H₂O₂、Phenol等抗逆相关。推测T4SS相关基因在该病原菌的接触、识别阶段起作用。

Type IV secretion system of Xanthomonas campestris pv. campestris is induced in MMX and related to stress resistance

Bacteria deliver DNA substrates, proteins and toxin to bacterial or eukaryotic target cells or the extracellular milieu generally by conjugation system, effector translocator and release/uptake systems of type IV secretion system (T4SS). Xanthomonas campestris pv. campestris (Xcc) is one of the most important model phytopathogen for study of plant-microbe interactions. In this study, the wild type and the T4SS mutant strains in different conditions were compared, and it presented that T4SS-deletion mutant of Xcc did not affect the growth in NYG and minimal medium MMX but had a weaker hypersensitive reaction (HR) on non-host pepper ECW-10R; the expression of T4SS genes was induced in MMX, and T4SS of Xcc was related to stress resistance to Ni²⁺, H₂O₂ and phenol. Taken together, it is speculated that T4SS is involved in the contact and recognition process during infection of this phytopathogen.