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A comprehensive RNA virome from molluscan transcriptomes reveals extensive diversity and modular genome evolution
Jiaxiang Li1, Kewei Chen1, Xin Chen1
1MoE Key Laboratory of Evolution and Marine Biodiversity, College of Marine Life Sciences, Institute of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Center for Ocean Carbon Neutrality, Ocean University of China, Qingdao, 266003, China.
Virologica Sinica
|June 4, 2026
Summary
Molluscs host a vast, understudied diversity of RNA viruses. This study identified 203 new RNA viruses, revealing their complex evolution and potential to infect various eukaryotes, impacting aquaculture and biodiversity.
Area of Science:
- Virology
- Marine Biology
- Genomics
Background:
- Mollusca is a major animal phylum with significant aquaculture value.
- While DNA viruses are studied, RNA viruses in molluscs remain largely unexplored.
- Understanding molluscan viromes is crucial for aquaculture health and biodiversity.
Purpose of the Study:
- To comprehensively identify and characterize RNA viruses within molluscs.
- To investigate the phylogenetic diversity and evolutionary patterns of molluscan RNA viruses.
- To explore the potential hosts and ecological roles of these newly discovered viruses.
Main Methods:
- Utilized a multi-stage RNA-dependent RNA polymerase (RdRP) discovery pipeline.
- Employed six-frame translation, profile-based homology search, and phylogenetic validation.
- Analyzed 223 molluscan metatranscriptomes across eight mollusc classes.
Main Results:
- Discovered 203 RNA viruses across five viral phyla and fifteen viral orders.
- Identified an increase in Pisuviricota-related lineages and extensive modular viral genome evolution.
- Linked 76% of identified RNA viruses to eukaryotic hosts, suggesting a broad host range.
Conclusions:
- Molluscs harbor a significantly greater diversity of RNA viruses than previously known.
- These viruses exhibit complex evolutionary dynamics, including gene rearrangement and co-evolution.
- Molluscs may act as crucial reservoirs for diverse RNA viruses with implications for various eukaryotic hosts.
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