Molecular diversity of tobacco vein banding mosaic virus.

Tobacco vein banding mosaic virus (TVBMV) is of increasing importance in tobacco production on the Chinese mainland. The 3'-terminal genomic sequences (1624 nucleotides) of 12 TVBMV isolates from China were determined and compared to the sequences of only four TVBMV isolates available in databanks. The results revealed that TVBMV consists of several phylogenetically distinguishable strains that show a degree of correlation with the geographical origin. Two isolates from Yunnan had a unique putative NIb/CP proteolytic cleavage site of Q/N that is uncommon for potyviruses, whereas other TVBMV isolates had the more typical Q/G amino acids at that site. One isolate (ZB6) from Zibo, Shandong Province, was predicted to have experienced recombination within the characterized genomic region.