Prevalence and molecular characterization of grapevine virus E, F and I populations in Greek vineyards

In this study, RT-PCR assays were developed and applied to investigate the prevalence of grapevine virus E (GVE), grapevine virus F (GVF) and grapevine virus I (GVI) in Greek vineyards. Grapevine samples from different viticultural areas of Greece were tested and the presence of all three vitiviruses was revealed. These viruses were mainly detected in grafted indigenous grapevine cultivars, with GVF being the most prevalent (24.7%, 200/809) in contrast to GVI (2.2%, 12/554) and GVE (1.6%, 12/752). To further study their intraspecies genetic variability and the phylogenetic relationships of their populations, sequence similarity analyses of the replicase and the coat protein gene segments of each virus, as well as from a fragment of the movement protein gene of GVI, were performed. Results revealed genetic variability in all three virus populations and high molecular diversity between Greek isolates of GVE and GVF, in contrast to Greek GVI isolates, which showed high homogeneity. Overall, our study advanced the current knowledge on grapevine-infecting vitiviruses and highlighted that special attention should be given to the widely spread GVF and its impact on grapevine should be further investigated.