Study on some Biological and Molecular Characterization of Tobacco streak virus Isolated from Sunflower

During 2007-2008 growing season، a total of 520 sunflower leaf samples with symptoms like vein clearing، cholorotic and necrotic local lesion، deformation and stunting which were suspected of being infected with Tobacco streak virus (TSV) were collected from sunflower fields of Azarbayijan-gharbi، Isfahan، Qom، Markazi، Tehran and Hamedan provinces. Infection with TSV in collected samples were determined serologically by enzyme – linked immunosorbent assay (DAS- ELISA) using a polyclonal antiserum. It was determined that 124 samples were infected with TSV. The percentage of TSV infection in sunflower fields of Azarbayijan-gharbi، Hamedan، Tehran، Qom، Isfahan and markazi provinces were 56%، 31%، 26%، 14%، 8. 8% and 0% respectively. The virus was propagated on maintenance hosts. TSV induced cholorotic local lesions symptoms on inoculated leaves of Chenopodium quinoa، C. amaranticolor and Vigna unguiculata. The virus caused systemic stunting، deformation and curl on leaves of Datura stramonium، Gomphrena globosa، Helianthus annuus and Vicia faba. Nicotiana benthemiana was symptomless. The molecular weight of coat protein under denaturing condition (SDS-PAGE) was estimated to be 30. 9 KD and Western blot confirmed the result of SDS-PAGE. IC- RT- PCR and RT- PCR were performed using a specific primer pair of TSV which had been designed according to a part of coat protein، and a fragment with 717 length was amplified.