移动遗传元件(MGEs),统称为“移动体”,会对微生物群落的适应性产生重大影响,从而对生态过程产生重大影响。海洋MGE主要与适应性性状的广泛地理和系统发育扩散有关。然而,这种动员体的结构是否在自然群落中表现出确定性模式仍然是一个悬而未决的问题。这项研究的目的是通过从TARAOceans调查中搜索公开可用的海洋宏基因组来表征海洋表面浮游细菌中共轭动员体的结构,连同分子标记,例如松弛酶和IV型分泌系统的IV型偶联蛋白(T4SS)。在表层海洋浮游细菌中,T4SS机械的回收量比松弛酶更多。此外,在确定的MGE中,可移动元素最丰富,数量超过自共轭序列。检测大量不完整的T4SS可以深入了解与MGE之间的反式活性相关的可能策略,和T4SS的辅助功能(例如蛋白质分泌),允许宿主在高度动态的海洋系统中保持较低的代谢负担。此外,结果表明,在整个海洋地区,MGE的地理分布广泛,而南大洋似乎与其他地区隔离。海洋动员体还显示了已知质粒数据库中存在的功能的高度相似性。此外,货物基因主要与DNA加工有关,但与抗生素耐药性几乎没有关系。最后,在MGE内部,整合和共轭元件显示出比质粒更广泛的海洋地理分散性。
Mobile genetic elements (
MGEs), collectively referred to as the \"mobilome\", can have a significant impact on the fitness of microbial communities and therefore on ecological processes. Marine
MGEs have mainly been associated with wide geographical and phylogenetic dispersal of adaptative traits. However, whether the structure of this mobilome exhibits deterministic patterns in the natural community is still an open question. The aim of this study was to characterize the structure of the conjugative mobilome in the ocean surface bacterioplankton by searching the publicly available marine metagenomes from the TARA Oceans survey, together with molecular markers, such as relaxases and type IV coupling proteins of the type IV secretion system (T4SS). The T4SS machinery was retrieved in more abundance than relaxases in the surface marine bacterioplankton. Moreover, among the identified MGEs, mobilizable elements were the most abundant, outnumbering self-conjugative sequences. Detection of a high number of incomplete T4SSs provides insight into possible strategies related to trans-acting activity between
MGEs, and accessory functions of the T4SS (e.g. protein secretion), allowing the host to maintain a lower metabolic burden in the highly dynamic marine system. Additionally, the results demonstrate a wide geographical dispersion of
MGEs throughout oceanic regions, while the Southern Ocean appears segregated from other regions. The marine mobilome also showed a high similarity of functions present in known plasmid databases. Moreover, cargo genes were mostly related to DNA processing, but scarcely associated with antibiotic resistance. Finally, within the
MGEs, integrative and conjugative elements showed wider marine geographic dispersion than plasmids.