Prevalence and genetic diversity of Grapevine virus A in Tunisia

Prevalence and genetic diversity of the complete CP gene of Grapevine virus A (GVA) were assessed in isolates from rootstocks, wine and table grape varieties and autochthonous grapevines. Wine grapes were the most infected (63%), followed by table grapes (49%) and rootstocks (44%). Autochthonous grapevines were the less infected (35%). Analyses of the complete coat protein sequences of 20 GVA isolates from the main grapevine growing areas of Tunisia identified three phylogroups, accounting, respectively, for 70% (group I), 25% (group IV) and 5% (group III) of the isolates. No sequences clustered into group II. Phylogenetic analyses indicated that Tunisian GVA isolates are not grouped by the host cultivar or geographic origin.