A large duplication in the 3′-untranslated region of a subpopulation of RNA2 of the UK-M isolate of barley mild mosaic bymovirus

The UK-M isolate of the bipartite barley mild mosaic bymovirus (BaMMV UK-M) cannot be fungally transmitted, and has previously been shown to have a 1092 nt deletion in the coding region of RNA2. We now report, using sequence and reverse transcriptase-polymerase chain reaction (RT-PCR) data, that a subpopulation of BaMMV UK-M RNA2 contains a direct imperfect sequence repeat of 552 nt in the 3′ untranslated region. The secondary structure of the 3′ end of RNA2, and its possible effects on replication of the virus, are also discussed