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چکیده
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North-west Iran and Eastern Anatolia is the origin of grapevine. This crop has been cultivated in Iran for thousands of years, however almost no attention therein has been paid to the virus infection status of the vines. After setting up a plant virology lab at the University of Tabriz we have now begun to survey the vineyards for presence of Grapevine fanleaf virus (GFLV) at first place because of its worldwide distribution. We have been inspecting vineyards in East and West Azarbaijan and Ardabil provinces in the northwest region since 2003. Leaf samples, expressing virus-like symptoms, were collected from the vineyards and subjected, first, to DASELISA with anti-GFLV antibody. As a result, infection with GFLV was proved in many samples although they formed a relatively small proportion of the collected samples. Then, an RT-PCR assay was adapted to identify the virus isolates at molecular level and determine the virus genetic diversity. Accordingly, total RNA from the ELISA-positive leaves was subjected to first strand cDNA synthesis with oligo d(T)16 and followed by PCR with the previously designed primers corresponding to the virus coat protein (CP) and movement protein (MP). Fragments with the expected sizes, amplified from many of the isolates, were cloned in a T/A cloning plasmid and subjected to sequencing. When the sequence data were subjected to phylogenetic analysis, a wide diversity (up to 17%) was revealed between the isolates at both CP and MP regions. Interestingly, some isolates appeared to be distinct among all the GFLV isolates recorded in the databases suggesting that they have probably originated from Iran. That a great majority of the ELISA-positive samples gave no amplification in the PCR suggested two possibilities. First, the primers used in this research were designed according to the GFLV isolates from other parts of the world and accordingly they might not anneal to the isolates from Iran. This is quite possible if the highly variable natu
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