New insights into the emergence of the grapevine "flavescence dorée" epidemics in Europe Malembic-Maher Sylvie1,*, Desqué Delphine1, Khalil Dima1, Salar Pascal1, Danet Jean-Luc1, Dubrana-Ourabah Marie-Pierre1, Duret Sybille1, Ember Ibolya2, Acs Zoltan8, Bartola Michele Della3, Materazzi Alberto3, Filippin Luisa4, Krnjajic Slobodan5, Toševski Ivo5,6, Lang Friederike7, Jarausch Barbara7, Kölber Maria8, Jovic Jelena5, Angelini Elisa4, Arricau-Bouvery Nathalie1, Maixner Michael7, Foissac Xavier1 1UMR1332 Biologie du Fruit et Pathologie, INRA, Université de Bordeaux, Villenave d'Ornon, France 2Szent István University, Faculty of Horticultural Science, Budapest, Hungary 3Department of Agriculture, Food and Environment (DAFE), University of Pisa, Italy 4CREA Viticulture and Enology, Conegliano, Treviso, Italy 5Department of Plant Pests, Institute of Plant Protection and Environment, Zemun, Serbia 6CABI, Delémont, Switzerland 7JKI, Institute for Plant Protection in Fruit Crops and Viticulture, Siebeldingen, Germany 8Genlogs Biodiagnosztika Ltd, Budapest, Hungary *Corresponding author e-mail: Sylvie Malembic-Maher (sylvie.malembic-maher@inra.fr)
Online published on 25 July, 2019. Abstract A survey of genetic diversity of “flavescence dorée” (FD)-related phytoplasmas in grapevines, alders and clematis as well as alder-feeding leafhoppers was conducted in France, Hungary, Germany, Italy and Serbia. Genotyping was based on the housekeeping gene map and on the vmp genes encoding surface variable membrane proteins. Transmission assays of the phytoplasmas were performed with alder and/or grapevine-feeding leafhoppers. The study demonstrated that European alders constitute an original reservoir of FD phytoplasma by hosting a high diversity of FD-related phytoplasma genotypes, also present in non viticultural areas. The alder phytoplasmas grouping in Vmp-I cluster were transmitted by the Macropsinae O. alni, but were not compatible with the FD phytoplasma vector on grapevine the Deltocephalinae Scaphoideus titanus. The alder phytoplasmas in Vmp-II and-III clusters were transmitted by the Deltocephalinae Allygus spp. and Orientus ishidae. Such pre-existing phytoplasmas were compatible with S. titanus transmissibility and can be responsible for the emergence of FD phytoplasma epidemics in grapevine. VmpA proteins of cluster II better adhered to Euscelidius variegatus and S. titanus insect cells and midguts than those of cluster I. Such adhesins might play a key role in the adaptation to new vectors. Top Keywords 16SrV-C and-D phytoplasmas, genetic diversity, vectorial competence, Vmp adhesins. Top |