Heyerhoff Benedikt, Engelen Bert, Bunse Carina
Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany.
Front Microbiol. 2022 Jul 7;13:863620. doi: 10.3389/fmicb.2022.863620. eCollection 2022.
Marine microbial communities are facing various ecosystem fluctuations (e.g., temperature, organic matter concentration, salinity, or redox regimes) and thus have to be highly adaptive. This might be supported by the acquisition of auxiliary metabolic genes (AMGs) originating from virus infections. Marine bacteriophages frequently contain AMGs, which allow them to augment their host's metabolism or enhance virus fitness. These genes encode proteins for the same metabolic functions as their highly similar host homologs. In the present study, we analyzed the diversity, distribution, and composition of marine viruses, focusing on AMGs to identify their putative ecologic role. We analyzed viruses and assemblies of 212 publicly available metagenomes obtained from sediment and water samples across the Baltic Sea. In general, the virus composition in both compartments differed compositionally. While the predominant viral lifestyle was found to be lytic, lysogeny was more prevalent in sediments than in the pelagic samples. The highest proportion of AMGs was identified in the genomes of . Overall, the most abundantly occurring AMGs are encoded for functions that protect viruses from degradation by their hosts, such as methylases. Additionally, some detected AMGs are known to be involved in photosynthesis, 7-cyano-7-deazaguanine synthesis, and cobalamin biosynthesis among other functions. Several AMGs that were identified in this study were previously detected in a large-scale analysis including metagenomes from various origins, i.e., different marine sites, wastewater, and the human gut. This supports the theory of globally conserved core AMGs that are spread over virus genomes, regardless of host or environment.
海洋微生物群落面临着各种生态系统波动（如温度、有机物浓度、盐度或氧化还原状态），因此必须具有高度的适应性。这可能得益于从病毒感染中获得的辅助代谢基因（AMGs）。海洋噬菌体通常含有AMGs，这使它们能够增强宿主的代谢或提高病毒的适应性。这些基因编码的蛋白质与它们高度相似的宿主同源物具有相同的代谢功能。在本研究中，我们分析了海洋病毒的多样性、分布和组成，重点关注AMGs以确定它们可能的生态作用。我们分析了从波罗的海沉积物和水样中获取的212个公开可用宏基因组中的病毒和组装体。总体而言，两个隔室中的病毒组成在成分上有所不同。虽然发现主要的病毒生活方式是裂解性的，但溶源性在沉积物中比在上层水体样本中更为普遍。在……的基因组中鉴定出了最高比例的AMGs。总体而言，最丰富出现的AMGs编码的功能是保护病毒不被宿主降解，如甲基化酶。此外，一些检测到的AMGs已知参与光合作用、7-氰基-7-脱氮鸟嘌呤合成和钴胺素生物合成等其他功能。本研究中鉴定出的几个AMGs先前在一项大规模分析中也被检测到，该分析包括来自各种来源的宏基因组，即不同的海洋地点、废水和人类肠道。这支持了全球保守的核心AMGs理论，即这些基因分布在病毒基因组中，而与宿主或环境无关。
