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A Capsidless Virus Is trans-Encapsidated by a Bisegmented Botybirnavirus
Jichun Jia1,2,3, Fan Mu1,2,3, Yanping Fu2
1State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural Universitygrid.35155.37, Wuhan, China.
Journal of Virology
|April 21, 2022
Summary
A newly discovered fungal virus, Sclerotinia sclerotiorum yadokarivirus 1 (SsYkV1), lacks its own capsid. This positive-sense single-stranded RNA virus utilizes the capsid of another unrelated double-stranded RNA virus for replication, expanding knowledge of viral life cycles.
Area of Science:
- Mycology
- Virology
- Molecular Biology
Background:
- RNA viruses typically package their genomes within self-produced capsids.
- Fungal viruses (mycoviruses) exhibit diverse replication strategies.
- The family Yadokariviridae comprises single-stranded RNA viruses with unique characteristics.
Purpose of the Study:
- To characterize newly identified mycoviruses in Sclerotinia sclerotiorum.
- To investigate the replication mechanism of Sclerotinia sclerotiorum yadokarivirus 1 (SsYkV1).
- To understand the phenomenon of trans-encapsidation in mycoviruses.
Main Methods:
- Identification and molecular characterization of mycoviruses.
- Genome sequencing and phylogenetic analysis of SsYkV1.
- Analysis of viral particle composition and host-virus interactions.
Main Results:
- Four new mycoviruses, including SsYkV1 (a +ssRNA virus), were identified in S. sclerotiorum.
- SsYkV1's genome was sequenced, revealing an RNA-dependent RNA polymerase (RdRp) domain.
- SsYkV1 RNA and RdRp were trans-encapsidated by Sclerotinia sclerotiorum botybirnavirus 3 (SsBV3), a dsRNA virus, forming a heterocapsid.
- SsYkV1 exhibited limited impact on the host's biological features.
Conclusions:
- This study provides a novel example of a yadokarivirus relying on an unrelated dsRNA virus for encapsidation.
- The findings expand the understanding of RNA virus life cycles and the phenomenon of trans-encapsidation.
- The discovery highlights the complex interactions and evolutionary strategies among mycoviruses.
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