The molecular cloning and nucleotide sequencing of the 3'-terminal region of Ornithogalum mosaic virus.

DNA complementary to the 3'-terminal 3684 nucleotides of the Ornithogalum mosaic potyvirus (OMV) genome was cloned and sequenced. The sequence consisted of a single large open reading frame which probably starts upstream of the cloned region. By comparison to other sequenced potyviruses, it was estimated that the clone contained the 3' non-coding (3'-NC) region, the coat protein (CP) gene and the large nuclear inclusion protein (NIb) gene, as well as approximately 85% of the small nuclear inclusion protein (NIa) gene. The 3'-NC region of 274 nucleotides showed 38% to 45% similarity to the corresponding regions of other potyviruses. The putative CP gene could encode a 253 amino acid coat protein with a calculated Mr of 28,807. Analysis of the amino acid sequences of OMV and other potyvirus proteins showed similarities of 66% to 77% for CP, 72% to 73% for NIb and 63% to 71% for NIa proteins. These data, as well as phylogenetic analysis of the CP sequences, suggested that OMV is a typical but taxonomically distinct potyvirus.