|CryoEM reconstruction of Penicillium stoloniferum virus S capsid, a partitivirus. EMDB entry |
|Group:||Group III (dsRNA)|
Partitiviridae are plant and fungi group III viruses with double stranded RNA genomes. Their name comes from the Latin partitius which means divided and they are called this as they have segmented genomes.
There are currently five recognized genera within the Partitiviridae family:
- Alphapartitivirus; type species: White clover cryptic virus 1
- Betapartitivirus; type species: Atkinsonella hypoxylon virus
- Cryspovirus; type species: Cryptosporidium parvum virus 1
- Deltapartitivirus; type species: Pepper cryptic virus 1
- Gammapartitivirus; type species: Penicillium stoloniferum virus S
Cryspoviruses infect apicomplexian protozoa of the genus Cryptosporidium, while viruses of the other genera infect plants and fungi. There are an additional fifteen species in the family unassigned to a genus.
Genome and structure
Partitiviruses have double stranded RNA genomes divided into two genomic segments and there may be additional subgenomic segments. The genome segments are packaged in the same virus particle, the larger segment codes for the RNA-dependent RNA polymerase and the smaller codes for the coat protein. The total length of the genome is 3000–10000 nucleotides in length. The virus particle is non-enveloped and icosahedral with a diameter between 30–35 nm.
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.
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