Flavescence dorée phytoplasma affecting grapevine (Vitis vinifera) newly reported in Portugal.
In 2007, during an official Flavescence dorée (FD) survey, typical FD symptoms, associated with desiccation of inflorescences, withering of clusters, irregular maturation of the wood, leaf rolling, typical vein banding and leaf yellowing on white grapevine cv. Loureiro, and leaf reddening on red grapevine cv. Vinhão, were observed in vineyards from Amares region in northern Portugal. In 2002, similar but less severe symptoms occurring in the same region were associated with 16SrI phytoplasmas ('Candidatus Phytoplasma asteris' [Phytoplasma asteris]), subgroup 16SrI-B. Total DNA extracted from cuttings and leaf samples collected from plants with and without symptoms was analysed by nested PCR. The pathogen was identified as phytoplasma with 16S rRNA sequences that were identical (99-100%) with those of group 16SrV. FD phytoplasmas from Portugal exhibited the characteristic FD-D TaqI RFLP pattern. This is the first report of FD-D in grapevine in northern Portugal.