Table_3_Viral Diversity and Its Relationship With Environmental Factors at the Surface and Deep Sea of Prydz Bay, Antarctica.XLSX

A viral metagenomic analysis of five surface and two bottom water (878 meters below surface, mbs, and 3,357 mbs) samples from Prydz Bay, was conducted during February–March 2015. The results demonstrated that most of the DNA viruses were dsDNA viruses (79.73–94.06%, except at PBI1, 37.51%). Of these, Caudovirales (Siphoviridae, Myoviridae, and Podoviridae) phages were most abundant in surface seawater (67.67–71.99%), while nucleocytoplasmic large DNA viruses (NCLDVs) (Phycodnaviridae, Mimiviridae, and Pandoraviridae accounted for >30% of dsDNA viruses) were most abundant in the bottom water (3,357 mbs). Of the ssDNA viruses, Microviridae was the dominant family in PBI2, PBI3, PBOs, and PBI4b (57.09–87.55%), while Inoviridae (58.16%) was the dominant family in PBI1. Cellulophaga phages (phi38:1 and phi10:1) and Flavobacterium phage 11b, infecting the possible host strains affiliated with the family Flavobacteriaceae of the phylum Bacteroidetes, were abundant in surface water dsDNA viromes. The long contig (PBI2_1_C) from the viral metagenomes were most similar to the genome architectures of Cellulophaga phage phi10:1 and Flavobacterium phage 11b from the Arctic Ocean. Comparative analysis showed that the surface viral community of Prydz Bay could be clearly separated from other marine and freshwater environments. The deep sea viral community was similar to the deep sea viral metagenome at A Long-term Oligotrophic Habitat Assessment Station (ALOHA, at 22°45′N, 158°00′W). The multivariable analysis indicated that nutrients probably played an important role in shaping the local viral community structure. This study revealed the preliminary characteristics of the viral community in Prydz Bay, from both the surface and the deep sea. It provided evidence of the relationships between the virome and the environment in Prydz Bay and provided the first data from the deep sea viral community of the Southern Ocean.

本研究于2015年2月至3月期间，对普里兹湾（Prydz Bay）的5份表层海水样品与2份底层海水样品（采集深度分别为表层下878米、3357米，单位均为表层下米（meters below surface, mbs））开展了病毒宏基因组学分析。分析结果显示，绝大多数DNA病毒为双链DNA病毒（double-stranded DNA virus, dsDNA），占比范围为79.73%~94.06%，仅PBI1样品例外，其dsDNA病毒占比仅为37.51%。其中，有尾噬菌体目（Caudovirales）噬菌体（包含长尾噬菌体科（Siphoviridae）、肌尾噬菌体科（Myoviridae）与短尾噬菌体科（Podoviridae））在表层海水中占比最高，占比范围为67.67%~71.99%；而核质大型DNA病毒（nucleocytoplasmic large DNA viruses, NCLDVs）（包括Phycodnaviridae、Mimiviridae与Pandoraviridae，其占dsDNA病毒的比例超过30%）在3357 mbs的底层海水中占比最高。在单链DNA病毒（single-stranded DNA virus, ssDNA）中，微小噬菌体科（Microviridae）是PBI2、PBI3、PBOs与PBI4b样品中的优势科，占比范围为57.09%~87.55%；而PBI1样品中的优势科为丝状噬菌体科（Inoviridae），占比达58.16%。噬纤维菌属噬菌体（Cellulophaga phage）phi38:1、phi10:1以及黄杆菌属噬菌体（Flavobacterium phage）11b的潜在宿主均属于拟杆菌门（Bacteroidetes）下的黄杆菌科（Flavobacteriaceae），这类病毒在表层海水dsDNA病毒组（virome）中丰度较高。本研究病毒宏基因组中获得的长重叠群（contig）PBI2_1_C，其基因组结构与北冰洋中的噬纤维菌属噬菌体phi10:1及黄杆菌属噬菌体11b的基因组结构最为相似。比较分析结果显示，普里兹湾表层病毒群落可与其他海洋及淡水环境的病毒群落显著区分开来。普里兹湾深海病毒群落与长期寡营养生境评估站（A Long-term Oligotrophic Habitat Assessment Station, ALOHA，位于北纬22°45′、西经158°00′）的深海病毒宏基因组特征相似。多变量分析结果表明，营养盐可能是塑造当地病毒群落结构的关键影响因素。本研究阐明了普里兹湾表层与深海海域病毒群落的初步特征，揭示了该区域病毒组与环境之间的关联，并首次提供了南大洋深海病毒群落的相关数据。