Analysis of genetic diversity of Grapevine fanleaf virus isolate from Fars and Kohgiluyeh-Boyer Ahmad provinces

Grapevine fanleaf virus belongs to the genus Nepovirus in the family Secoviridae. It causes an important disease of grapevine worldwide. To determine the genetic diversity of GFLV in Southern Iran, samples of grapevine and weeds were collected from vineyards in Fars and Kohgiluyeh-Boyer Ahmad provinces. ELISA using specific antibody of GFLV showed that grapevine, bermudagrass, knotweed, Johnson grass and raspberry plants are natural reservoir hosts of GFLV. In mechanical inoculation of different isolates of GFLV to Chenopodium quinoa, mosaic, leaf malformation and sharpening of leaf edges were developed in inoculated plants. Complete length of GFLV coat protein gene amplified in RT-PCR using specific primers was subjected to RFLP analysis using TaqI endonuclease. It was shown that GFLV isolates belong to 11 haplotypes. Phylogentic analysis based on the nucleotide sequence of the coat protein gene showed that Iranian isolates of GFLV have distinct position in phylogentic tree. Moreover, evidence of divergent evolution was observed between isolates from northwest, northeast and south of Iran. It confirms that genetic makeup of GFLV may be affected by geographical isolation.