Abstract
The sequence of the 3'-terminal 3116 nucleotides of satsuma dwarf virus (SDV) RNA1 was determined. The sequence contains a part of a single open reading frame of 2868 nucleotides and a non-coding region of 248 nucleotides upstream of the poly(A) tail. The C-terminal region of the ORF is apparently homologous to the RNA-dependent RNA polymerase of viruses. The amino acid sequence of this region shows homology with that of the genus Comovirus (28%, cowpea mosaic virus) followed by the genus Nepovirus (25%, grapevine fanleaf virus). There is no significant homology with the viruses of other genera, suggesting that SDV is comparatively closer to the como- and nepoviruses. However, the low homology of RNA-dependent RNA polymerase gene among SDV, the genus Comovirus and the genus Nepovirus in contrast to high conservation among viruses of the genus Comovirus (51-61%) and the genus Nepovirus (35-70%) suggests that SDV is distinct from those so far sequenced como- and nepoviruses.
