The inner membrane protein DotU of Aeromonas veronii is an important component of the minimal core conserved membrane proteome required for the formation of an envelope-transmembrane complex. This protein functions in a type VI secretion system (T6SS), and the role of this T6SS during the pathogenic process has not been clearly described. A recombinant A. veronii with a partial disruption of the dotU gene (720 bp of the in-frame sequence) (defined as ∆dotU) was constructed by two conjugate exchanges. We found that the mutant ∆dotU allele can be stably inherited for more than 50 generations. Inactivation of the A. veronii dotU gene resulted in no significant changes in growth or resistance to various environmental changes. However, compared with the wild-type strain colony, the mutant ∆dotU colony had a rough surface morphology. In addition, the biofilm formation ability of the mutant ∆dotU was significantly enhanced by 2.1-fold. Conversely, the deletion of the dotU gene resulted in a significant decrease in pathogenicity and infectivity compared to those of the A. veronii wild-type strain. Our findings indicated that the dotU gene was an essential participant in the pathogenicity and invasiveness of A. veronii TH0426, which provides a novel perspective on the pathogenesis of TH0426 and lays the foundation for discovering potential T6SS effectors.

中文翻译：

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T6SS内膜蛋白DotU的失活导致严重减毒并降低Veronii气单胞菌TH0426的致病性。

Veronii气单胞菌的内膜蛋白DotU是形成包膜-跨膜复合物所需的最小核心保守膜蛋白质组的重要组成部分。该蛋白在VI型分泌系统（T6SS）中起作用，尚未明确描述该T6SS在致病过程中的作用。通过两次共轭交换构建了一部分dotU基因（框内序列为720 bp）（定义为ΔdotU）破坏的重组拟南芥。我们发现突变的ΔdotU等位基因可以稳定遗传超过50代。veronii dotU基因的失活导致生长或对各种环境变化的抗性没有明显变化。然而，与野生型菌株菌落相比，ΔdotU突变菌落具有粗糙的表面形态。此外，ΔdotU突变体的生物膜形成能力显着提高了2.1倍。相反，与ver.ii veronii野生型菌株相比，dotU基因的缺失导致致病性和感染性显着降低。我们的研究结果表明，dotU基因是拟南芥TH0426致病性和侵袭性的必不可少的参与者，这为TH0426的发病机理提供了新的观点，并为发现潜在的T6SS效应器奠定了基础。