Occurrence of Grapevine fanleaf virus (Nepovirus foliumflabelli) in the Western Black Sea region of Türkiye and phylogenetic analysis based on partial coat protein gene.

This study investigated the presence of Grapevine fanleaf virus (GFLV, Nepovirus foliumflabelli) in Turkish vineyards and assessed the genetic relationships of detected isolates using partial coat protein (CP) sequences. During the 2017 growing season, 418 grapevine samples were collected from vineyards in Amasya, Çorum, and Tokat, which are major viticultural regions in Türkiye. GFLV was initially screened by DAS-ELISA and subsequently verified through RT-PCR. The combined assays revealed an infection incidence of 27.75%. Seven representative PCR products were sequenced, and phylogenetic analysis demonstrated that Turkish isolates clustered together with 12 Iranian isolates, forming a group distinct from other global strains. These results provide new insights into the distribution and genetic diversity of GFLV populations in Türkiye.