New analysis sheds light on diversity and ecological footprint of marine RNA viruses

Community- and "species"-level analysis on Global Ocean RNA sequences sampled from waters worldwide has shed light on the poorly understood diversity and ecological footprint of marine RNA viruses, according to a new report.

The findings underscore the important roles marine RNA viruses play in the ocean ecosystem. Viruses are ubiquitous in all domains of life and play a critical role as drivers of evolution, biological diversity, and microbe-mediated biogeochemical cycling. Most efforts to understand Earth's marine virome have focused on DNA viruses, which are known to be abundant, diverse, and key ecosystem players. Although recent ocean sequencing surveys have identified thousands of previously unknown RNA viruses and provided new insights into their evolutionary origins and global abundance, very little is known about global marine RNA virus diversity, ecology, and ecosystem roles. Using the Global Ocean RNA sequence dataset provided by the Tara Oceans Expeditions, Guillermo Dominguez-Huerta and colleagues explore the global diversity and ecological footprint of marine RNA viruses. According to the findings, marine RNA viruses predominantly infect protist and fungal hosts, including plankton. As has been observed in DNA viruses, they sort into four distinct ecological zones, largely determined by depth and, to a lesser extent, latitudinal change.

What's more, Dominguez-Huerta et al. found that the influence of RNA viruses on the ocean ecosystem is large – auxiliary metabolic genes in the RNA virome indicate that several crucial plankton processes like photosynthesis and ocean carbon flux can be affected by RNA viruses.

For reporters interested in trends, this study builds upon a previous April 2022 Science Research Article that evaluated nearly 28 terabases of Global Ocean RNA sequences collected during the Tara Oceans Expeditions. The findings revealed thousands of previously unknown marine RNA viruses and provided new insights into early RNA virus evolution.