The first complete genome sequence of iris severe mosaic virus

The first complete genome sequence of ISMV was determined by deep sequencing of a small RNA library constructed from ISMV-infected samples and rapid amplification of cDNA ends (RACE) PCR. The ISMV genome consists of 10,403 nucleotides excluding the poly(A) tail and contains a large open reading frame encoding a polyprotein of 3316 amino acids. Putative proteolytic cleavage sites were identified by BLAST analysis. The ISMV polyprotein showed highest amino acid sequence identity to that encoded by onion yellow dwarf virus. Phylogenetic analysis of the polyprotein amino acid sequence confirmed that ISMV forms a cluster with shallot yellow stripe virus, Cyrtanthus elatus virus A, narcissus degeneration virus and onion yellow dwarf virus. These results confirm that ISMV is a distinct member of the genus Potyvirus.