Conjugation-mediated DNA delivery is the primary mode for antibiotic resistance spread in bacteria; yet, molecular mechanisms regulating the conjugation process remain largely unexplored. While conjugative plasmids typically require bacterial attachment to solid surfaces for facilitation of donor-to-recipient proximity, the pLS20 conjugative plasmid, prevalent among Gram-positive Bacillus spp., uniquely requires fluid environments to enhance its transfer. Here, we show that pLS20, carried by Bacillus subtilis, induces multicellular clustering, which can accommodate various species, hence offering a stable platform for DNA delivery in a liquid milieu. We further discovered that induction of pLS20 promoters, governing crucial conjugative genes, is dependent on the presence of donor cell flagella, the major bacterial motility organelle. Moreover, the pLS20 regulatory circuit is controlled by a mechanosensing signal transduction pathway responsive to flagella rotation, thus activating conjugation gene expression exclusively during the host motile phase. This flagella-conjugation coupling strategy may allow the dissemination of the plasmid to remote destinations, allowing infiltration into new niches.

中文翻译：

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鞭毛旋转促进细菌结合质粒的转移。


偶联介导的 DNA 递送是抗生素耐药性在细菌中传播的主要模式;然而，调节偶联过程的分子机制在很大程度上仍未得到探索。虽然偶联质粒通常需要细菌附着在固体表面以促进供体与受体的接近，但普遍存在于革兰氏阳性芽孢杆菌属中的 pLS20 偶联质粒独特地需要流体环境来增强其转移。在这里，我们表明枯草芽孢杆菌携带的 pLS20 诱导多细胞聚集，可以容纳各种物种，从而为液体环境中的 DNA 递送提供了一个稳定的平台。我们进一步发现，控制关键结合基因的 pLS20 启动子的诱导取决于供体细胞鞭毛（主要细菌运动细胞器）的存在。此外，pLS20 调节回路受响应于鞭毛旋转的机械感应信号转导通路控制，因此仅在宿主运动期激活结合基因表达。这种鞭毛-偶联偶联策略可能允许质粒传播到远程目的地，从而渗透到新的生态位。