Quadriviridae is a family of double-stranded RNA viruses with a single genus Quadrivirus.[1] The fungi Rosellinia necatrix serves as a natural host. The name of the group derives from the quadripartite genome of its members where in Latin quad means four. The genus has three species.[2][3]
Structure

Mycoviruses in the family Quadriviridae have a non-enveloped isometric capsid which consists of 60 copies of heterodimers of the structural proteins P2 and P4. The diameter of the capsid is around 48 nm.[2][3]
Genome

Family member genomes are composed of double-stranded RNA. They are divided in to four segments which each code for a protein. The length of the different segments are between 3.5 and 5.0 kbp. The total genome is around 16.8 kbp. Inside the capsid with the genome there is also the RNA-dependent RNA polymerase.[2][3]
Life cycle
Quadriviruses are transmitted internally. They are propagated during cell division and hyphal anastomosis. Viral replication occurs in the cytoplasm. It follows the double-stranded RNA virus replication model. Double-stranded RNA virus transcription is the method of transcription. The fungi Rosellinia necatrix serves as a natural host.[2][3]
Taxonomy

The family Quadrivirdae has one genus Quadrivirus, which contains the following species:[4]
- Quadrivirus ichi (Rosellinia necatrix quadrivirus 1)
- Quadrivirus ni
- Quadrivirus sani
References
- ^ Chiba, S; Castón, JR; Ghabrial, SA; Suzuki, N; Ictv Report, Consortium (November 2018). "ICTV Virus Taxonomy Profile: Quadriviridae". The Journal of General Virology. 99 (11): 1480–1481. doi:10.1099/jgv.0.001152. PMID 30265238.
- ^ a b c d "ICTV Report Quadriviridae".
- ^ a b c d e "Viral Zone". ExPASy. Retrieved 13 August 2015.
- ^ "Virus Taxonomy: 2024 Release". International Committee on Taxonomy of Viruses. Retrieved 7 March 2025.