BIOLOGICAL AND PHYLOGENETIC CHARACTERISTICS OF AN IRANIAN GLADIOULS ISOLATE OF Bean yellow mosaic virus

During 2008-2009، a total of 154 gladiolus (Gladiolus grandiflorus) corms were collected from the distribution centers in Karaj (Iran). After cultivation، fresh leaf samples of all germinated corms were tested by DAS-ELISA، which revealed the infection of 74. 02% of plants with Bean yellow mosaic virus (BYMV). Following biological purification of an isolate، designated as BYMV-GPK، its host range was determined. The molecular mass of BYMV-GPK coat protein was estimated as 34 KDa by SDS-PAGE، which was confirmed by western blot analysis. DAS-ELISA and tissue print immunoassay (TPIA) techniques showed similar sensitivity in detection of BYMV in leaf tissue of infected gladiolus plants، but none of them was able to detect BYMV in corm tissue of the same infected plants. Two fragments of GPK genome، corresponding to HC-Pro and 3´ end regions with 600 and 1100 bp in length، respectively، were amplified by RT-PCR. Phylogenetic analysis based on the nucleotide and deduced amino acid sequence of HC-Pro and genomic 3´ end region showed that BYMV isolates clustered into separate groups according to their host origin and GPK isolate was closely related to a trifolium and other gladiolus isolates.