''Quadriviridae'' is a family of double-stranded RNA viruses with a single genus ''Quadrivirus''. The

fungi A fungus (plural, : fungi or funguses) is any member of the group of Eukaryote, eukaryotic organisms that includes microorganisms such as yeasts and Mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified ...

'' Rosellinia necatrix'' serves as a natural host. The name of the group derives from the ''quadri''partite genome of its members where in

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power ...

''quad'' means four. There is only one species in this family: ''Rosellinia necatrix quadrivirus 1''.

Structure

Mycovirus Mycoviruses (Ancient Greek: μύκης ' ("fungus") + Latin '), also known as mycophages, are viruses that infect fungi. The majority of mycoviruses have double-stranded RNA (dsRNA) genomes and isometric particles, but approximately 30% have pos ...

es in the family ''Quadriviridae'' have a non-enveloped isometric

capsid A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may ...

which consists of 60 copies of heterodimers of the structural proteins P2 and P4. The diameter of the capsid is around 48 nm.

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 to 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 RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand complementary to a given RNA template. This is in contrast to t ...

Life cycle

Quadriviruses are transmitted internally. They are propagated during cell division and

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

anastomosis An anastomosis (, plural anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf veins, or streams. Such a connection may be normal ...

. Viral replication occurs in the

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. ...

. 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.

Taxonomy

The family ''Quadrivirdae'' has one genus ''Quadrivirus'' which contains the species: * ''Rosellinia necatrix quadrivirus 1''

References

External links

ICTV Report: ''Quadriviridae''

{{Taxonbar, from=Q18811737 Virus families Riboviria