Abstract
Based on structural differences in the ORF2 region, the sobemoviruses have been subdivided into southern cowpea mosaic virus (SCPMV)-like and cocksfoot mottle virus (CfMV)-like types of genome organization. However, nearly identical amino acid sequences are encoded by these subgroups in different reading frames of ORF2, suggesting that insertion or deletion of appropriate nucleotides could restore similar genomic organizations for these viruses. We resequenced the regions of inconsistency for isolates of four SCPMV-like viruses: lucerne transient streak virus, ryegrass mottle virus, southern bean mosaic virus, and SCPMV. A comparison of nucleic acid composition of these sequences with previously published ones revealed crucial differences that established a common CfMV-like genomic organization for these sobemoviruses.