''Quadriviridae'' is a family of

double-stranded RNA viruses Double-stranded RNA viruses (dsRNA viruses) are a Polyphyly, polyphyletic group of viruses that have Nucleic acid double helix, double-stranded genomes made of ribonucleic acid. The double-stranded genome is used to transcribe a Sense (molecular ...

with a single genus ''Quadrivirus''. The

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

Rosellinia necatrix ''Rosellinia necatrix'' is a fungal plant pathogen infecting several hosts including apples, apricots, avocados, cassava, strawberries, pears Pears are fruits produced and consumed around the world, growing on a tree and harvested in the N ...

'' 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 of the ...

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

Structure

Mycoviruses 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 ma ...

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 In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding g ...

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.

Life cycle

Quadriviruses are transmitted internally. They are propagated during cell division and hyphal anastomosis. 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 Double-stranded RNA viruses (dsRNA viruses) are a polyphyletic group of viruses that have double-stranded genomes made of ribonucleic acid. The double-stranded genome is used to transcribe a positive-strand RNA by the viral RNA-dependent RNA ...

replication model. Double-stranded RNA virus transcription is the method of transcription. The fungi ''

'' 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