Comparison of the complete sequences of five different isolates of Potato virus A (PVA), genus Potyvirus

The complete nucleotide (nt) and deduced amino acid (aa) sequences of isolates Ali, U, Her (from potato, Solanum tuberosum) and TamMV (from tamarillo, Solanum betacea) of Potato virus A (PVA, genus Potyvirus) were determined and compared with the previously reported sequence of PVA isolate B11. Most parts (proteins) of the polyprotein showed over 95% aa sequence similarity. The cylindrical inclusion (CI) protein and the 6K 1 protein were the most conserved proteins among the five isolates. TamMV was the most different isolate. Sequence similarity between TamMV and the other isolates was the lowest in regions close to the 5'-end [5'-non-translated region (NTR) and P1 region] and 3'-end (N-terminus of coat protein) of the genome. However, the termini of the genome (the first 60 nt of the 5'-NTR and the entire 3'-NTR) were highly similar in all five isolates. A frameshift region in the replicase (NIb) was identified the PVA isolates Ali, B11, Her and U, as compared to TamMV and other potyviruses.