VIRION
Non-enveloped icosahedral capsid, about 35-40 nm in diameter with a T=2* icosahedral symmetry 
. The two genomic segments are encapsidated separately.
GENOME
Segmented linear dsRNA genome: 2 segments encoding potentially for 2 proteins. Segments are about 1.4-3.0 kb each, total size about 4 kb
GENE EXPRESSION
Each genomic segment is monocistronic.
ENZYMES
REPLICATION
CYTOPLASMIC
- Virus penetrates into the cytoplasm.
- Transcription of the dsRNA genome by viral polymerase occurs inside the virion, so that dsRNA is never exposed to the cytoplasm. This plus-strand transcript is used as template for translation.
- (+)RNAs are encapsidated in virion particle, inside which they are transcribed to give RNA (-) molecules with which they become base-paired to produce dsRNA genomes.
- Mature are transmitted to new cell by cytoplasmic exchange, sporogenesis or Hyphal anastomosis.