Family: Hypoviridae

Genus: Hypovirus

Distinguishing features

Since only one genus is currently recognized, the genus description corresponds to the family description. 

Species demarcation criteria

Viruses belonging to different species are differentiated by genetic organization or genome expression, as well as by major differences in nucleic acid sequence identity. Thus, Cryphonectria hypovirus 1 (CHV1) differs from Cryphonectria hypovirus 2 (CHV2) in the presence or absence, respectively, of a papain-like proteinase in ORF A. CHV1 and CHV2 isolates share less than 60% overall aa sequence identity with each other. Cryphonectria hypovirus 3 (CHV3) and Cryphonectria hypovirus 4 (CHV4) each contain a single ORF, but isolates of the two species share less than 50% overall sequence identity. In addition, infection by CHV1 isolates results in a white or near-white phenotype in the fungus; CHV2 infection results in an orange-brown phenotype; CHV3 and CHV4 isolates have little effect on fungal pigment. Infection by members of any of the four species may reduce fungal virulence. 

Member species

Related, unclassified viruses