The polymerase encodes an amber stop codon which is the site of a readthrough event within ORF1, producing two products necessary for replication.

[5] The RNA is encapsulated in an icosahedral (T=3) capsid, composed of 180 units of a single coat protein 27–42K in size; the virion measures 28–35 nm in diameter, and it is not enveloped.

Translation takes place by leaky scanning, −1 ribosomal frameshifting, viral initiation, and suppression of termination.

Virions may spread by water, root growth into infected soil, contact between plants, pollen, or seed, depending on the virus species.

These viruses may be successfully transmitted by grafting or mechanical inoculation, and both the virion and the genetic material alone are infective.

Viral DI RNAs with their small size and cis-acting elements are good templates both in vivo and in vitro on which to study RNA replication.