Sheam Md Moinuddin, Luo Elaine
Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, United States.
Center For Computational Intelligence to Predict Health & Environmental Risks, University of North Carolina at Charlotte, Charlotte, NC 28262, United States.
ISME J. 2025 Jan 2;19(1). doi: 10.1093/ismejo/wraf094.
Nucleocytoplasmic large DNA viruses, or "giant viruses," are prevalent in marine environments, infecting diverse eukaryotic lineages and influencing the marine carbon cycle. Their genomes harbor wide range of auxiliary metabolic genes that influence biogeochemical processes. This study integrates planktonic (5-4000 m) and particle-associated (4000 m) metagenomic samples in the North Pacific Subtropical Gyre, along with particulate export flux data at 4000 m, to investigate the vertical transport of giant viruses and their correlation with carbon export through space and time. By analyzing metagenomic samples over a period of 6 years across 15 depths, we curated a database of 37 giant virus population genomes and 1496 contigs and investigated their spatiotemporal variability and functional capacity in the open ocean. We reported multiple lines of evidence supporting the viral shuttle hypothesis, including the vertical transport of giant viruses from the upper ocean to abyssal depths and their positive correlation with particulate carbon export flux at 4000 m, particularly a giant species closely related to Phaeocystis globosa virus known to infect a bloom-forming alga. We identified giant viruses encoding diverse auxilary metabolic genes, including genes associated with photosynthesis, nutrient transport, and energy metabolism. These auxiliary metabolic genes displayed depth-specific distributions, which we postulate reflect depth-specific adaptations to light-energy and nutrient-limited conditions along the water column. This study provides critical insights into biogeochemical impacts of giant viruses by identifying key giant viruses that can impact export processes and depth-specific distributions of auxiliary metabolic genes impacting biogeochemical processes along the open ocean water column.
核质大DNA病毒，即“巨型病毒”，在海洋环境中普遍存在，感染各种真核生物谱系并影响海洋碳循环。它们的基因组包含广泛的辅助代谢基因，这些基因影响生物地球化学过程。本研究整合了北太平洋亚热带环流中的浮游（5 - 4000米）和颗粒相关（4000米）宏基因组样本，以及4000米处的颗粒输出通量数据，以研究巨型病毒的垂直运输及其与碳输出在时空上的相关性。通过分析6年期间跨越15个深度的宏基因组样本，我们建立了一个包含37个巨型病毒群体基因组和1496个重叠群的数据库，并研究了它们在公海中的时空变异性和功能能力。我们报告了多条支持病毒穿梭假说的证据，包括巨型病毒从上洋到深渊深度的垂直运输，以及它们与4000米处颗粒碳输出通量的正相关，特别是一种与已知感染形成水华藻类的球形棕囊藻病毒密切相关的巨型物种。我们鉴定出编码多种辅助代谢基因的巨型病毒，包括与光合作用、营养物质运输和能量代谢相关的基因。这些辅助代谢基因呈现出深度特异性分布，我们推测这反映了沿水柱对光能和营养物质限制条件的深度特异性适应。这项研究通过识别能够影响输出过程的关键巨型病毒以及影响公海水柱生物地球化学过程的辅助代谢基因的深度特异性分布，为巨型病毒的生物地球化学影响提供了重要见解。
