Partitiviridae

Partitiviridae
CryoEM reconstruction of Penicillium stoloniferum virus S capsid, a partitivirus. EMDB entry EMD-5161[1]
Virus classification
Group: Group III (dsRNA)
Order: Unassigned
Family: Partitiviridae
Genera
  • Alphapartitivirus
  • Betapartitivirus
  • Cryspovirus
  • Deltapartitivirus
  • Gammapartitivirus

Partitiviridae is a family of viruses. Fungi and plants serve as natural hosts. There are currently 56 species in this family, divided among 5 genera.[2][3] Their name comes from the Latin partitius which means divided and they are called this as they have segmented genomes.

Genome and structure

Viruses in Partitiviridae are non-enveloped, with icosahedral geometries, and T=1 symmetry. The diameter is around 35-40 nm. 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. Genomes are linear and around 1.4-3.0kb in length. The genome codes for 2 proteins.[2]

Genus Structure Symmetry Capsid Genomic Arrangement Genomic Segmentation
CryspovirusIcosahedralT=1Non-EnvelopedLinearSegmented
AlphapartitivirusIcosahedralT=1Non-EnvelopedLinearSegmented
DeltapartitivirusIcosahedralT=1Non-EnvelopedLinearSegmented
BetapartitivirusIcosahedralT=1Non-EnvelopedLinearSegmented
GammapartitivirusIcosahedralT=1Non-EnvelopedLinearSegmented

Life Cycle

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.[2]

Genus Host Details Tissue Tropism Entry Details Release Details Replication Site Assembly Site Transmission
CryspovirusProtistsNoneCell division; sporogenesis; hyphal anastomosisCell division; sporogenesis; hyphal anastomosisCytoplasmCytoplasmCell division; sporogenesis; hyphal anastomosis
AlphapartitivirusNoneCytoplasmCytoplasmCell division
DeltapartitivirusPlantsNoneViral movement; mechanical inoculationCell divisionCytoplasmCytoplasmCell division
BetapartitivirusNoneCytoplasmCytoplasmCell division
GammapartitivirusFungiNoneCytoplasmic exchange; hyphal anastomosisCytoplasmic exchange; hyphal anastomosisCytoplasmCytoplasmCytoplasmic exchange; hyphal anastomosis

Taxonomy

There are currently five recognized genera within the Partitiviridae family:

Group: dsRNA

[3]

Cryspoviruses infect apicomplexian protozoa of the genus Cryptosporidium,[4] while viruses of the other genera infect plants and fungi. There are an additional fifteen species in the family unassigned to a genus.

Phylogenetics

Based on the RNA polymerase gene this group can be divided into four clades (I-IV).[5] Four isolates from animals and protozoans form a fifth clade. Clades I-IV consist of mixtures of partitivirus-like sequences from plants and fungi.

References

  1. ↑ Tang, J.; Pan, J.; Havens, W. M.; Ochoa, W. F.; Guu, T. S. Y.; Ghabrial, S. A.; Nibert, M. L.; Tao, Y. J.; Baker, T. S. (2010). "Backbone Trace of Partitivirus Capsid Protein from Electron Cryomicroscopy and Homology Modeling". Biophysical Journal. 99 (2): 685–694. doi:10.1016/j.bpj.2010.04.058. PMC 2905076Freely accessible. PMID 20643089.
  2. 1 2 3 "Viral Zone". ExPASy. Retrieved 15 June 2015.
  3. 1 2 ICTV. "Virus Taxonomy: 2014 Release". Retrieved 15 June 2015.
  4. ↑ Nibert ML, Woods KM, Upton SJ, Ghabrial SA (2009) Cryspovirus: a new genus of protozoan viruses in the family Partitiviridae. Arch Virol 154(12):1959-1965
  5. ↑ Liu H, Fu Y, Xie J, Cheng J, Ghabrial SA, Li G, Yi X, Jiang D (2012) Discovery of Novel dsRNA Viral Sequences by In Silico Cloning and Implications for Viral Diversity, Host Range and Evolution. PLoS One. 2012;7(7):e42147.
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