Non-enveloped capsid with T=1 icosahedral symmetry and composed of 60 protein subunit monomers. However, each of the subunit is thought to contain two genetically duplicated domains, these 120 putative domains might therefore adopt a pseudo-T=2 structure. The capsid is about 35-40 nm in diameter. The four genomic segments are encapsidated separately.


Segmented linear dsRNA genome about 12.5 kb: 4 segments encoding for 4 proteins.


Each genomic segment encodes for a single protein.



  1. Virus penetrates into the cytoplasm.
  2. 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.
  3. (+)RNAs are encapsidated in virion particle, in which they are transcribed to give RNA (-) molecules with which they become base-paired to produce dsRNA genomes.
  4. Mature virions are transmitted to new cell by cytoplasmic exchange, sporogenesis or Hyphal anastomosis.