Evolutionary relationship between luteoviruses and other RNA plant viruses based on sequence motifs in their putative RNA polymerases and nucleic acid helicases

Comparative studies of sequence motifs in the RNA polymerases and nucleic acid helicases of positive-sense RNA plant viruses have provided a new scheme for the classification of these pathogens. We propose a new luteovirus supergroup which should be added to the already described Sindbisvirus-like and picornavirus-like supergroups. Sequence motifs of nucleic acid helicases and RNA polymerases which previously were considered to be specific for each of the two supergroups now occur together within this new supergroup. We propose that this new viral supergroup provides an evolutionary link between the other two supergroups.