RNA Viruses in Aquatic Unicellular Eukaryotes.

Area of Science:

• Marine virology
• Eukaryotic microbiology
• Molecular biology

Background:

• RNA viruses are increasingly recognized as a significant component of marine viral communities.
• Despite their prevalence, only a limited number of RNA virus species infecting marine single-celled eukaryotes have been formally described.
• Existing knowledge primarily focuses on viruses within the order Picornavirales, with a few exceptions in Alvernaviridae and Reoviridae families.

Purpose of the Study:

• To review and detail the current understanding of RNA viruses that infect aquatic unicellular eukaryotes.
• To highlight the diversity and ecological significance of these viruses in marine environments.
• To synthesize findings from recent studies suggesting extraordinary diversity in aquatic RNA viromes.

Main Methods:

• Literature review of published studies on marine RNA viruses and their hosts.
• Analysis of sequence data to identify and characterize RNA viruses in marine environments.
• Compilation of information on known RNA virus species, their hosts, and taxonomic affiliations.

Main Results:

• Twelve RNA virus species infecting marine single-celled eukaryotes are currently described.
• Diatoms are hosts for eight of these species, while dinoflagellates, raphidophytes, thraustochytrids, and prasinophytes host the remaining four.
• Recent research indicates a vast, largely uncharacterized diversity of RNA viruses in aquatic viromes, likely infecting protist hosts.

Conclusions:

• RNA viruses play a crucial ecological role in marine ecosystems, interacting with unicellular eukaryotic hosts.
• The known diversity of RNA viruses infecting marine eukaryotes is likely a significant underrepresentation of the true viral diversity.
• Further research is essential to fully elucidate the scope and impact of RNA viruses in marine environments.