十字花科黑腐病菌pilY基因与涌动有关

pilY is Involved in Swarming Motility in Xanthomonas campestris pathovar campestris

细胞的运动在细菌的趋化、粘附、生物膜形成以及致病等过程中发挥关键作用。细菌的运动方式主要有三种:游动(Swimming motility)、涌动(Swarming motility)和颤动(Twitching motility)。游动和涌动由鞭毛介导,而颤动由Ⅳ型纤毛介导。全基因组测序结果显示,十字花科黑腐病菌(Xanthomonas campestris pv.campestris,Xcc)存在一套完整的合成Ⅳ型纤毛的基因,而且能够产生Ⅳ型纤毛;但有证据表明Xcc不能进行颤动。在实验室之前的研究中发现,Ⅳ型纤毛基因pilH和pilG与Xcc的游动和涌动有关。在本研究中,通过缺失突变体和互补菌的构建,以及表型分析策略,对Ⅳ型纤毛基因pilY进行了生物学功能鉴定。结果发现,pilY缺失突变体的涌动能力比野生型菌株显著增强,而互补菌株的涌动能力与野生型的相似,证明pilY基因具有抑制Xcc涌动的功能。此外,本研究还发现pilY缺失不影响Xcc的生长繁殖、致病力以及致病因子的产生。

Cell motility plays a critical role in bacterial chemotaxis, adhesion, biofilm formation, and pathogenesis. There are three major types of bacterial cell motility: swimming, swarming and twitching. It has been shown that swimming and swarming are mediated by flagella, and twitching is mediated by type Ⅳ pilus. Whole genome sequencing revealed that Xanthomonas campestris pv. campestris(Xcc) encodes a complete set of type Ⅳ pilus genes, and Xcc indeed can produce type Ⅳ pilus. However, it has been demonstrated that Xcc can not twitching. Our lab previously found that the type Ⅳ pilus gene pilH and pilG is related to swimming and swarming of Xcc. To determine the biological function of the type Ⅳ pilus gene pilY, in this study, the deletion mutant and its complemented strain were constructed, and then the phenotype of these strain were analysed. Results showed that the swarming motility of the pilY deletion mutant is significantly stronger than that of the wild type strain, while the swarming motility of the complemented strain is identical to that of the wild type strain, demonstrated that pilY functioning as an inhibitor of Xcc swarming motility. In addition, this research found that pilY deletion had no effect on the growth, pathogenicity and production of pathogenic factors of Xcc.