Recently, the research "Diversity and Function of Mountain and Polar Supraglacial DNA Viruses" was published in Science Bulletin (IF= 18.)9）。The results of this study are the first to systematically describe the diversity, function, and public health risk assessment of DNA viruses on polar glaciers.
Background:
Polar glaciers, which cover 10% of the Earth's surface, are typical of extreme environments where various forms of life exist. Viruses are abundant and active in the supperglacial ecosystem and play a vital role in controlling the supperglacial microbial community. However, the current understanding of the viral ecology of the glacier surface and its potential impact on downstream ecosystems is still limited.
Technical approach
In this study, microbial metagenomics and viromics were used to analyze 21 high-altitude glaciers (2731-6675 m above sea level;5183 meters above sea level), including samples of snow, ice, ice meltwater, and ice dust, and obtained 25 metaviromes and 96 microbial metagenomic datasets (including 85 recently reported in the TG2G catalog).
Fig.1 Study area and sample collection
An overview of the main contents
Based on the Glacier Virus and Microbial Metagenomic Dataset (187 samples in total), this study reconstructed the DNA viral genome of the glacier ecosystem and provided the largest genome list (S**G) of the glacier virome, including 10,840 virus genomes from more than 17 virus families in 38 polar glaciers, spanning habitat environments such as snow, ice, ice meltwater, and ice dust, expanding the current glacier virome by more than 15 times. Glacier DNA viruses are highly specific but also exhibit low public health risks compared to viruses in other ecosystems. The viral community on glaciers is mainly limited by habitat, and the viral activity of ice dust is the highest. In this study, lysogenic viruses were observed to be prevalent in all habitats, especially in low-temperature ice dust, but high levels of lysogenic viruses were present in snow and ice. In addition, it has been found that glacier viruses can be associated with about 83% of prokaryotic phyla, and have the genetic potential to promote metabolism through a variety of auxiliary metabolic genes and increase the host's cold adaptation, cell mobility, and phenolic carbon utilization under harsh environmental conditions. The data from this study highlight the importance of viruses in the biogeochemical cycle on glaciers and their potential impact on the sustainability of downstream ecosystems. This study also expands researchers' understanding of the diversity, function and adaptability of viruses on glaciers, and provides a basis for future research on the world's glaciers.
Fig.2 Overview of the viral genome (S**G) on the glacier. (a) Venn diagram of the viral population (votus) on the glacier;(b) votus that is common and unique to different regions;(c) the proportion of votus that have been classified;(d)the composition of the classified votus;(e) Relative abundance of classified and unclassified votus. 
Fig.3 Differences and diversity of viral communities on glaciers. (a) Principal coordinate analysis (PCOA) of viral communities on glaciers based on different similarity indicators of Bray Curtis;(b) Unique and shared votus in different glacial habitats;(c) (d) (e) Diversity index box plot analysis of glacial virus populations.
Fig.4 Life strategies and activities of viruses on glaciers. (a) Proportion of lysogenic virus votus in all glacial votus;(b) Relative abundance of lysogenic viruses;(c) Relative virus-to-bacteria ratio (vbrrelative) of lyogenic viruses based on silico virus-host**;(d) Vbrrelative of lytic viruses based on silico virus-host**;(e) Viral abundance (VA), bacterial abundance (BA) and virus-to-bacteria ratio (VBR) in low-temperature ice dust and ice meltwater over the Tibetan Plateau(f) Lytic and lytic virus yields of ice dust and glacial meltwater on the Tibetan Plateau (lytic VP and lysogenic VP, respectively).
Fig.5 Virus-host connection and host lineage-specific virus-host dynamics on glaciers. (a) Phylogenomic development of bacteria on glaciers and the links between viruses and bacteria. Heat map showing (b) host relative abundance, (c) log10 (vbrrelative);(d) Pearson correlation analysis of viruses (log10 (virus tpm)) and hosts (log10 (host tpm));(e) Pearson correlation analysis of log10 (vbrrelative) and log10 (host TPM).
Fig.6 Helper metabolic genes (AMGs) were detected in the upperglacial virus population. (a) Several major pathways that may be associated with AMG on glaciers. (b) Genome structure, highlighting the location of AMGs and the three-dimensional structure of AMG-encoded proteins.
References
diversity and function of mountain and polar supraglacial dna viruses. science bulletin, 2023.