The purpose of this study was to determine the distribution of tobacco streak virus in the vegetable fields of the Markazi, Qom, Lorestan and Hamadan provinces.This study was performed in 2017, and a total of 475 samples of parsley plants were collected. Using the specific antibody of the virus, the TSV infection of these samples was investigated by the immunosorbent assay through the double antibody sandwich ELISA (DAS-ELISA) method. The results of this study indicated that the TSV infection of parsley samples in Qom, Markazi, Hamedan and Lorestan provinces were 14, 18.8, 15.4 and 20.1%, respectively. Also, the phylogenetic analysis of nucleotide and amino acid sequences of the coat protein of these isolates showed that the Iranian isolate and the Indian isolate could be clustered along with each other. The phylogenetic tree obtained based on nucleotide and amino acid sequences of the coat protein gene, showed that the isolates were divided into two and three clusters, respectively. Iranian isolates were clustered along with global TSV isolates and other Ilarviruses formed a separate cluster. This is the first report of TSV genetic diversity in Iran, and also the first report of TSV infection in the vegetable fields of Qom, Markazi, Hamedan and Lorestan provinces.
