Submitted to: American Society for Virology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: February 1, 2004
Publication Date: July 10, 2004
Citation: French, R.C., Stenger, D.C. 2004. Complete nucleotide sequences of agropyron mosaic virus and hordeum mosaic virus support monnophyly of the genus rymovirus, family potyviridae. American Society For Virology Meeting. (Not published in journal.) Technical Abstract: The genus Rymovirus within the family Potyviridae has had an interesting history. First constructed as a taxon for eriophyid mite-transmitted potyviruses, subsequent viral gene sequence data revealed mite transmission is a polyphyletic characteristic. Some virus species were placed in a new genus, Tritimovirus. Further, the monophyly of viruses remaining in genus Rymovirus relative to aphid-transmitted members of the genus Potyvirus has been questioned (Potyviridae family. AAB/CMI Descriptions of Plant Viruses, no. 366). To resolve the status of rymoviruses, complete nucleotide sequences of Agropyron mosaic virus (AgMV) and Hordeum mosaic virus (HoMV) were determined. The AgMV (9540 nt) and HoMV (9463 nt) sequences each encode a single polyprotein with predicted gene products characteristic of monopartite species of the family Potyviridae. AgMV and HoMV are most closely related to each other (68.5% nucleotide; 71.6% amino acid sequence identity) and equidistant (~53% nucleotide; ~49% amino acid sequence identity) from a third rymovirus, Ryegrass mosaic virus (RGMV). Phylogenetic analyses by three methods (neighbor joining, maximum parsimony, and Bayesian analysis) consistently place the three known species of the genus Rymovirus in an exclusive clade of eriophyid mite-transmitted viruses with a most recent common ancestor basal to a clade containing 34 aphid-transmitted species of the genus Potyvirus. Because AgMV, HoMV, and RGMV share a reciprocal monophyletic relationship with species of the genus Potyvirus, and are mutually divergent in sequence and type of vector, the genus Rymovirus remains to be a useful taxonomic unit within the family Potyviridae.