| Partitiviridae | |
|---|---|
 | |
| CryoEM ofPenicillium stoloniferum virus S capsid,EMD-5161[1] | |
 | |
| TEM ofPenicillium stoloniferum virus S | |
Virus classification | |
| (unranked): | Virus |
| Realm: | Riboviria |
| Kingdom: | Orthornavirae |
| Phylum: | Pisuviricota |
| Class: | Duplopiviricetes |
| Order: | Durnavirales |
| Family: | Partitiviridae |
Partitiviridae is a family ofdouble-stranded RNA viruses.[2]Plants,fungi, andprotozoa serve as natural hosts. It has been suggested that they can also infectbacteria.[3] The name comes from the Latinpartitius, which means divided, and refers to the segmented genome of partitiviruses. The family contains five genera.[4][5]
Viruses in the familyPartitiviridae arenon-enveloped with icosahedral geometries and T=1 symmetry.[6] The diameter of partitiviruses is around 25–43 nm.[4]
Partitiviruses have double-strandedRNA genomes divided into two genomic segments, and there may be additional subgenomic segments. The twogenome segments are packaged in separate virus particles. They code for two separate proteins. The first segment codes for theRNA-dependent RNA polymerase (RdRp), and the second segment codes for thecoat protein. The segments are around 1.4–3.0 kbp in length, while the total genome length is around 3.0–4.8 kbp.[4][6]
Viral replication is cytoplasmic. Entry into the host cell is achieved by penetration into the host cell. Replication follows the double-stranded RNA virus replication model. Double-stranded RNA virus transcription is the method of transcription. The virus exits the host cell by cell-to-cell movement. Fungi and plants serve as the natural host.[4][6] Cryspoviruses infectapicomplexian protozoa of the genusCryptosporidium,[7] while viruses of the other genera infect plants and fungi. It has been suggested that they can also infect bacteria.
| Genus | Host details | Tissue tropism | Entry details | Release details | Replication site | Assembly site | Transmission |
|---|---|---|---|---|---|---|---|
| Cryspovirus | Protists | None | Cell division; sporogenesis; hyphal anastomosis | Cell division; sporogenesis; hyphal anastomosis | Cytoplasm | Cytoplasm | Cell division; sporogenesis; hyphal anastomosis |
| Alphapartitivirus | None | Cytoplasm | Cytoplasm | Cell division | |||
| Deltapartitivirus | Plants | None | Viral movement; mechanical inoculation | Cell division | Cytoplasm | Cytoplasm | Cell division |
| Betapartitivirus | None | Cytoplasm | Cytoplasm | Cell division | |||
| Gammapartitivirus | Fungi | None | Cytoplasmic exchange; hyphal anastomosis | Cytoplasmic exchange; hyphal anastomosis | Cytoplasm | Cytoplasm | Cytoplasmic exchange; hyphal anastomosis |
Based on the RNA polymerase gene this group can be divided into four clades (I-IV). Four isolates from animals and protozoans form a fifth clade. Clades I–IV consist of mixtures of partitivirus-like sequences from plants and fungi.[8]
The family contains the following genera:[4][5]