The nucleotide sequences of the 3’ terminal regions of papaya ringspot virus strains W and P

The sequences of cDNA clones encoding most of the NI b protein, the coat protein and the 3 ' untranslated region of papaya ringspot virus (PRV) strains W and P have been determined. The open reading frame of P strain PRV was confirmed by amino acid analysis. Nucleotide sequence comparisons of these strains show that they share a 98-2 % identity in their NI b gene regions and a 97-7 % identity in their coat protein genes. The sequences of these two strains are distinct from other potyvirus types, confirming their classification as two strains of the same virus. The NI b amino acid sequence possesses conserved amino acids characteristic of RNA-dependent RNA polymerases. Comparison of the coat protein amino acid sequence with those of other potyviruses shows perfectly conserved amino acids which may have functional significance