Comparison of the coat protein genes of Lettuce big-vein associated virus isolates from Australia with those of isolates from other continents.

The complete coat protein (CP) nucleotide sequences of seven Lettuce big-vein associated virus (LBVaV) isolates from Australia were compared to those of 22 other LBVaV and five tobacco stunt virus (TStV) isolates. On phylogenetic analysis, clade I contained only LBVaV isolates from Europe, sub-clade IIa only Australian LBVaV isolates, IIb only Japanese LBVaV isolates, and IIc only TStV isolates from Japan. In the amino acid sequences deduced, the central region of the gene was most divergent. Mean Dn/Ds ratios were 0.283 and 0.124 for clades I and II, respectively. The suggestion that TStV is a strain of LBVaV was supported.