ANALYSES OF COMPLETE NUCLEOTIDE SEQUENCE OF IRANIAN ISOLATE OF MAIZE DWARF MOSAIC VIRUS (MDMV) AND NOTES ON THE ORIGIN AND EVOLUTION OF MDMV

Complete nucleotide sequence of an Iranian isolate of Maize dwarf mosaic virus (MDMV-Ir) was determined. The viral genome comprises 9499 nucleotides, excluding a 3′-terminal poly A tail. It consists of a 139 nucleotide long 5′noncoding region, a 234 nucleotide long 3′noncoding region and an open reading frame (ORF) which encodes a single polyprotein of 3042 amino acid residues. MDMV-Ir shares 86.4% to 91.9% nucleotide identity and 93.9% to 97.3% amino acid sequence similarity with other isolates of the virus. The nucleotide sequence identity of MDMV-Ir with full sequences of other cereal potyviruses available in GenBank ranged from 54 to 70.5%. The putative amino acid sequences of MDMV-Ir proteins showed 29.8% to 60% similarity to corresponding proteins of other cereal viruses in the GenBank. Sequence comparisons and phylogenetic analyses of the complete genome and derived polyproteins revealed that MDMV-Ir has the highest similarity to the Bulgarian isolate of MDMV, and among other cereal potyviruses it has the closest relationship to Sorghum mosaic virus. These analyses also indicated that MDMV populations are a monophyletic group originated in the Mediterranean basin.