Notes on Genus: Chrysovirus

icosahedra
icosahedra

Type member: Penicillium chrysogenum virus

Contents

General Description

This is the only genus in the family Chrysoviridae. Members are mostly mycoviruses with double stranded RNA genomes in four segments. The genus was previously classified in the family Partitiviridae but this now only contains members with two genome components and sequence data indicate that members of the two families are only distantly related. Some chrysovirus sequences 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. The name is from the species of the fungus host of the type member.

Morphology

Virions isometric (icosahedral), not enveloped, 35-40 nm in diameter.

Genome

Linear, double stranded RNA with four segments, ranging from about 2.8-3.6 kb in size.

Genus Genomic Organization

There are four RNAs, each encoding a single protein.
  • RNA1 (c. 3.6 kb) encodes a polymerase of 125-130 kDa
  • RNA2 (3.1-3.2 kb) encodes a coat protein of 100-110 kDa
  • RNA3 (c. 3.0 kb) encodes a protein of 90-102 kDa (function unknown)
  • RNA4 (2.8-2.9 kb) encodes a protein of 80-100 kDa (possibly a minor virion protein)

Type Member Genomic Organization

There are four RNAs:
  • RNA1 (3.6kb) encodes a polymerase of 129 kDa
  • RNA2 (3.2kb) encodes a coat protein of 109 kDa
  • RNA3 (3.0kb) encodes a protein of 101 kDa (function unknown)
  • RNA4 (2.9kb) encodes a minor virion protein of 95 kDa