Distinguishing features

Members of the genus Megabirnavirus infect filamentous fungi. The exemplar member of the type species of the genus has bisegmented dsRNA genome of 7.2–8.9 kbp including long UTRs (1.6–1.7 kb) upstream of the 5′-proximal ORF on the coding strands. The genome is encapsidated into non-enveloped spherical particles of approximately 50 nm in diameter. The RNA-directed RNA polymerase (RdRP) is translated from bicistronic transcripts of dsRNA1 as a CP-RdRP fusion product via programmed −1 ribosomal frameshifting.

Virion

See discussion under family description. 

Genome organization and replication

See discussion under family description.

Biology

See discussion under family description.

Species demarcation criteria

Not yet defined since only a single species has been assigned.

Member species

Virus names, the choice of exemplar isolates, and virus abbreviations, are not official ICTV designations.

Related, unclassified viruses 

See discussion under family description.