Molecular characterization of Iranian wheat stripe virus shows its taxonomic position as a distinct species in the genus Tenuivirus

Summary.

The full lengths of three genome segments of Iranian wheat stripe virus (IWSV) were amplified by reverse transcription (RT) followed by polymerase chain reaction (PCR) using a primer complementary to tenuivirus conserved terminal sequences. The segments were sequenced and found to comprise 3469, 2337, and 1831 nt, respectively. The gene organization of these segments is similar to that of other known tenuiviruses, each displaying an ambisense coding strategy. IWSV segments, however, are different from those of other viruses with respect to the number of nucleotides and deduced amino acid sequence for each ORF. Depending on the segment, the first 16–22 nt at the 5′ end and the first 16 nt at the 3′ end are highly conserved among IWSV and rice hoja blanca virus (RHBV), rice stripe virus (RSV) and maize stripe virus (MStV). In addition, the first 15–18 nt at the 5′ end are complementary to the first 16–18 nt at the 3′ end. Phylogenetic analyses showed close similarity and a common ancestor for IWSV, RHBV, and Echinochloa hoja blanca virus (EHBV). These findings confirm the position of IWSV as a distinct species in the genus Tenuivirus.