Outer membrane vesicles (OMVs) can function as nanoscale vectors that mediate bacterial interactions in microbial communities. How bacteria recognize and recruit OMVs inter-specifically remains largely unknown, thus limiting our understanding of the complex physiological and ecological roles of OMVs. Here, we report a ligand-receptor interaction-based OMV recruitment mechanism, consisting of a type VI secretion system (T6SS)-secreted lipopolysaccharide (LPS)-binding effector TeoL and the outer membrane receptors CubA and CstR. We demonstrated that Cupriavidus necator T6SS1 secretes TeoL to preferentially associate with OMVs in the extracellular milieu through interactions with LPS, one of the most abundant components of OMVs. TeoL associated with OMVs can further bind outer membrane receptors CubA and CstR, which tethers OMVs to the recipient cells and allows cargo to be delivered. The LPS-mediated mechanism enables bacterial cells to recruit OMVs derived from different species, and confers advantages to bacterial cells in iron acquisition, interbacterial competition, and horizontal gene transfer (HGT). Moreover, our findings provide multiple new perspectives on T6SS functionality in the context of bacterial competition and HGT, through the recruitment of OMVs.

外膜囊泡 (OMV) 可以作为介导微生物群落中细菌相互作用的纳米级载体。细菌如何识别和招募 OMVs 在很大程度上仍然是未知的，因此限制了我们对 OMVs 复杂的生理和生态作用的理解。在这里，我们报告了一种基于配体-受体相互作用的 OMV 募集机制，由 VI 型分泌系统 (T6SS) 分泌的脂多糖 (LPS) 结合效应器 TeoL 和外膜受体 CubA 和 CstR 组成。我们证明了Cupriavidus necatorT6SS1 分泌 TeoL，通过与 OMV 最丰富的成分之一 LPS 相互作用，优先与细胞外环境中的 OMV 结合。与 OMV 相关的 TeoL 可以进一步结合外膜受体 CubA 和 CstR，后者将 OMV 束缚在受体细胞上并允许货物被递送。LPS 介导的机制使细菌细胞能够募集来自不同物种的 OMV，并赋予细菌细胞在铁获取、细菌间竞争和水平基因转移 (HGT) 方面的优势。此外，我们的研究结果通过招募 OMV 为细菌竞争和 HGT 环境下的 T6SS 功能提供了多种新视角。