Temperate phages can interact with bacterial hosts through lytic and lysogenic cycles via different mechanisms. Lysogeny has been identified as the major form of bacteria-phage interaction in the coral-associated microbiome. However, the lysogenic-to-lytic switch of temperate phages in ecologically important coral-associated bacteria and its ecological impact have not been extensively investigated. By studying the prophages in coral-associated Halomonas meridiana, we found that two prophages, Phm1 and Phm3, are inducible by the DNA-damaging agent mitomycin C and that Phm3 is spontaneously activated under normal cultivation conditions. Furthermore, Phm3 undergoes an atypical lytic pathway that can amplify and package adjacent host DNA, potentially resulting in lateral transduction. The induction of Phm3 triggered a process of cell-lysis accompanied by the formation of outer membrane vesicles (OMVs), and Phm3 attached to OMVs. This unique cell-lysis process was controlled by a four-gene lytic module within Phm3. Further analysis of the Tara Ocean dataset revealed that Phm3 represents a new group of temperate phages that are widely distributed and transcriptionally active in the ocean. Therefore, the combination of lateral transduction mediated by temperate phages and OMV transmission offers a versatile strategy for host-phage co-evolution in marine ecosystems.

中文翻译：

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珊瑚相关盐单胞菌中具有横向转导能力的活性前噬菌体


温带噬菌体可以通过不同的机制通过裂解和溶原循环与细菌宿主相互作用。溶原性已被确定为珊瑚相关微生物组中细菌-噬菌体相互作用的主要形式。然而，生态上重要的珊瑚相关细菌中温带噬菌体的溶原性向裂解性转变及其生态影响尚未得到广泛研究。通过研究珊瑚相关的 Meridiana 中的原噬菌体，我们发现两种原噬菌体 Phm1 和 Phm3 可以被 DNA 损伤剂丝裂霉素 C 诱导，并且 Phm3 在正常培养条件下会自发激活。此外，Phm3 经历非典型裂解途径，可以扩增和包装邻近的宿主 DNA，可能导致横向转导。 Phm3 的诱导引发了细胞裂解过程，并伴随着外膜囊泡 (OMV) 的形成，Phm3 附着在 OMV 上。这种独特的细胞裂解过程由 Phm3 内的四基因裂解模块控制。对塔拉海洋数据集的进一步分析表明，Phm3 代表了一组新的温带噬菌体，它们在海洋中广泛分布且转录活跃。因此，温带噬菌体介导的横向转导和 OMV 传输的结合为海洋生态系统中宿主-噬菌体共同进化提供了一种通用策略。