The Xanthomonas oryzae pv. oryzae type IV pilus alignment subcomplex protein PilN contributes to regulation of bacterial surface-associated behaviours and T3SS system
The Xanthomonas oryzae pv. oryzae type IV pilus alignment subcomplex protein PilN contributes to regulation of bacterial surface-associated behaviours and T3SS system
复制标题
米黄单胞菌 pv.
DOI：
10.1111/ppa.13157
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发表时间：
2020-02-26
期刊：
影响因子：
2.7
通讯作者：
Chen, Gongyou
中科院分区：
文献类型：
--
作者：
Li, Yilang;Yan, Yichao;Chen, Gongyou
革兰氏阴性植物病原体米黄单胞菌 pv。 oryzae (Xoo) 能够感染宿主水稻并有效地在维管组织中定殖。 IV型菌毛（T4P）是主要毒力因子之一，在Xoo通过宿主维管组织的迁移中发挥重要作用。在这里，我们鉴定了 PilN，一种 T4P 排列子复合体蛋白，它参与游泳运动的调节，并分析了它对细菌表面相关行为和毒力的贡献。我们发现 pilN 缺失突变体表现出显着降低的抽搐运动性和几乎检测不到的 T4P 主要菌毛 PilA 水平，以及增强的生物膜形成和胞外多糖 (EPS) 产生。此外，Xoo 中 pilN 基因的缺失会导致宿主水稻的毒力受损，并减弱 III 型分泌系统 (T3SS) 基因的表达，而该基因表达与 PilA 组装无关。相关 pilN 基因的反式表达能够将 pilN 突变体的抽搐运动性和生物膜形成恢复至野生型水平，但部分恢复 EPS 产生和毒力。此外，在 pilN 突变体中，编码 HrpG 正调节因子的 trh 和 xrvA 基因的表达降低。我们的结果表明 PilN 在细菌毒力和细胞表面相关行为中执行多种功能。
The gram-negative plant pathogen Xanthomonas oryzae pv. oryzae (Xoo) is able to infect the host rice and effectively colonize in vascular tissues. The type IV pilus (T4P) is one of the major virulence factors playing an important role in migration of Xoo through host vascular tissues. Here, we identified PilN, a T4P alignment subcomplex protein, which is involved in regulation of swimming motility, and analysed its contribution to bacterial surface-associated behaviours and virulence. We found that the pilN deletion mutant exhibited dramatically reduced twitching motility and scarcely detectable levels of T4P major pili PilA, as well as enhanced biofilm formation and exopolysaccharide (EPS) production. In addition, deletion of the pilN gene in Xoo resulted in impaired virulence in host rice and attenuated type III secretion system (T3SS) genes expression, which is independent of PilA assembly. Expression of the relevant pilN gene in trans was capable of restoring twitching motility and biofilm formation to the wild-type levels in the pilN mutant but partially recovering EPS production and virulence. Moreover, the expression of trh and xrvA genes, which encode the HrpG positive regulators, was decreased in the pilN mutant. Our results suggest that PilN executes versatile functions in bacterial virulence and cell surface-associated behaviours.