Genome sequence of dahlia mosaic virus revisited: molecular characterization and genetic diversity of DMV and dahlia common mosaic virus.

Dahlia mosaic virus (DMV) and dahlia common mosaic virus (DCMV), members of the genus Caulimovirus, are associated with dahlia mosaic disease and are prevalent in dahlia plants in the USA and in several other parts of the world. To resolve a discrepancy in the publicly available genomic sequence of DMV and its taxonomic status with respect to DCMV, the complete genome sequences of several DMV and DCMV isolates from different regions of the USA were determined. Based on this sequence analysis, we resolved a discrepancy in the previously reported DMV sequence, confirmed that DMV possesses a genome structure and organization that is typical of a caulimovirus, and found that it shares 81% identity in the polyprotein coding sequence and 85% in the RT and RNase H domains of the polyprotein with DCMV. Greater sequence divergence was observed in the remainder of their genomes. As per the guidelines for demarcation of caulimoviruses at the species level by the International Committee on Taxonomy of Viruses, we propose that DMV and DCMV should be considered variants of the same virus.