comparison of the coat protein gene sequence of iranian canola- infecting beet western yellows virus isolates

beet western yellows virus (bwyv), a species of the genus polerovirus in the family luteoviridae, is an agriculturally important virus infecting over 150 plant species in 23 dicotyledonous families worldwide. a survey of bwyv in canola fields in golestan and tehran provinces of iran using indirect triple antibody sandwich enzyme-linked immunosorbent assay (tas-elisa) indicated 8.3 % infection. the presence of bwyv was confirmed by amplification of the coat protein (cp) gene of the virus via running a reverse transcription-polymerase chain reaction (rt-pcr) on total rna extracted from elisa positive leaf tissues. dna sequences of the bwyv coat protein (cp) gene of seven iranian isolates were determined and compared at the nucleotide (nt) and amino acid (aa) levels with those of twelve bwyv isolates from different countries deposited in genbank. sequence analysis data showed that the identity of bwyv-cp at nt and aa levels among the iranian isolates were 93.4 % to 100 % and 93.2 % to 100 %, respectively. the maximum similarity of isolates at nt and aa levels were 97.2 and 96.6 %, which occurred among two iranian isolates (ir 8 and ir 100) and four isolates from france (l39967 and x13063) and england (l39973 and l39970). the recombination analysis among the nineteen isolates including seven iranian isolates revealed that there was no distinct intra-specific recombination event among bwyv isolates. this is the first report of sequencing and analyzing of the bwyv cp gene of iranian bwyv isolates.