Molecular characterization of Hop mosaic virus: its serological and molecular relationships to Hop latent virus

The 3'-terminal sequence of hop mosaic virus (HpMV) genomic RNA was determi ned. A cDNA of approximately 1.8 kbp was amplified from the HpMV genome by 3' RACE using a degenerate primer, which was designed to anneal to the over lapping region of open reading frames (ORFs) 2 and 3 of eight carlavirus ge nomes. The sequence contained three ORFs, encoding proteins of 7-, 34-, and 11-kDa, which corresponded to ORFs 4, 5, and 6 of the carlavirus genome, r espectively. The amino acid sequence of ORF 5, encoding the coat protein (C P) of HpMV, shows the highest identity (67%) to that of Hop latent virus (H pLV). The HpMV CP N-terminal sequence differs from that of HpLV, but the ce ntral and C-terminal sequences of the CP of both viruses are similar. The s equence similarity possibly causes the cross-reaction of heterologous antib odies of HpMV and HpLV. Phylogenetic analyses based on the CP amino acid an d 3' non-coding region sequences indicate close relationships among HpMV, H pLV, and Potato virus M. We report here the first molecular characterizatio n of HpMV genomic RNA.