Notes on Genus: Partitivirus
Type member: Atkinsonella hypoxylon virus
This is now the only mycovirus genus in the family Partitiviridae
. The name is from the Latin partitus
, meaning "divided". Similar viruses of fungi with four genomic components are placed in the genus Chrysovirus
). Some sequences with high similarity to partitiviruses have now been isolated from plants; it is not yet clear whether these are genuine plant pathogens, or whether they have been isolated from a parasitic fungus within the plant.
Virions isometric (icosahedral), not enveloped, 30-35 nm in diameter.
Bipartite, linear, double stranded RNA. The segments are unrelated, separately encapsidated, and 1.4-2.2 kb in size. Additional segments of satellite or defective dsRNA may also be present.
Genus Genomic Organization
The segments are monocistronic and similar in size. RNA1 (the slightly larger segment) encodes an RNA-dependent RNA polymerase (77-86 kDa in currently sequenced members), while RNA2 encodes the coat protein (57-76 kDa in currently sequenced members).
Type Member Genomic Organization
- RNA1 (2180 nt) encodes a polymerase of 77.6 kDa
- RNA2 (2135 nt) encodes the coat protein of 73.7 kDa