To study the role of wild areas around the vineyards in the epidemiology of Flavescence dorée (FD) and track origin of new foci, two phytoplasma genetic markers, dnaK and malG, were developed for FD phytoplasma characterization. The two genes and the vmpA locus were used to genetically characterize FDp populations at seven agroecosystems of a wine-growing Italian region. Vitis vinifera, "gone-wild" V. vinifera and rootstocks, Clematis spp. and Scaphoideus titanus adults were sampled within and outside the vineyards. A range of genotypes infecting the different hosts of the FDp epidemiological cycle was found. FD-C type isolates were fairly homogeneous compared to FD-D ones. Most of the FD-D variability was described by malG sequence, and a duplication of this locus was demonstrated for this strain. Co-infection with FD-C and FD-D strains was rare, suggesting possible competition between the two. Similar levels of FDp genetic variation, recorded for grapevines or leafhoppers of cultivated and wild areas and co-occurrence of many FDp genotypes inside and outside the vineyards supported the importance of wild or abandoned Vitis spp. plants and associated S. titanus in the epidemiology of the disease. Genetic profiles of FDp found in Clematis were never found in the other hosts, indicating that this species does not take part in the disease cycle in the area. Due to the robustness of dnaK for discriminating between FD-C and FD-D strains and the high variability of malG sequence, these are efficient markers to study FDp populations and epidemiology at a small geographical scale.IMPORTANCE Flavescence dorée, a threatening disease of grapevine caused by FD phytoplasma (FDp), is distributed within the most important wine producing areas of Europe and causes severe impacts on both vineyard productivity and landscape management. FDp is a quarantine pest in Europe, and despite the efforts to contain the pathogen, the disease is still spreading. In this work, new genetic markers for the fine genetic characterization of FDp at local scale are presented. Our findings improve the knowledge of FDp epidemiological cycle and the possibility to track the route of the FDp infection. In particular, due to its high genetic variability, one of the newly developed markers could be sufficient to track origin of new infection foci, either from the wild areas or from nurseries.

Genetic diversity of Flavescence dorée phytoplasmas at vineyard scale

Ripamonti, Matteo;Bosco, Domenico;
2019-01-01

Abstract

To study the role of wild areas around the vineyards in the epidemiology of Flavescence dorée (FD) and track origin of new foci, two phytoplasma genetic markers, dnaK and malG, were developed for FD phytoplasma characterization. The two genes and the vmpA locus were used to genetically characterize FDp populations at seven agroecosystems of a wine-growing Italian region. Vitis vinifera, "gone-wild" V. vinifera and rootstocks, Clematis spp. and Scaphoideus titanus adults were sampled within and outside the vineyards. A range of genotypes infecting the different hosts of the FDp epidemiological cycle was found. FD-C type isolates were fairly homogeneous compared to FD-D ones. Most of the FD-D variability was described by malG sequence, and a duplication of this locus was demonstrated for this strain. Co-infection with FD-C and FD-D strains was rare, suggesting possible competition between the two. Similar levels of FDp genetic variation, recorded for grapevines or leafhoppers of cultivated and wild areas and co-occurrence of many FDp genotypes inside and outside the vineyards supported the importance of wild or abandoned Vitis spp. plants and associated S. titanus in the epidemiology of the disease. Genetic profiles of FDp found in Clematis were never found in the other hosts, indicating that this species does not take part in the disease cycle in the area. Due to the robustness of dnaK for discriminating between FD-C and FD-D strains and the high variability of malG sequence, these are efficient markers to study FDp populations and epidemiology at a small geographical scale.IMPORTANCE Flavescence dorée, a threatening disease of grapevine caused by FD phytoplasma (FDp), is distributed within the most important wine producing areas of Europe and causes severe impacts on both vineyard productivity and landscape management. FDp is a quarantine pest in Europe, and despite the efforts to contain the pathogen, the disease is still spreading. In this work, new genetic markers for the fine genetic characterization of FDp at local scale are presented. Our findings improve the knowledge of FDp epidemiological cycle and the possibility to track the route of the FDp infection. In particular, due to its high genetic variability, one of the newly developed markers could be sufficient to track origin of new infection foci, either from the wild areas or from nurseries.
2019
1
10
https://aem.asm.org/content/early/2019/03/12/AEM.03123-18
Rossi, Marika; Pegoraro, Mattia; Ripamonti, Matteo; Abbà, Simona; Beal, Dylan; Giraudo, Alessia; Veratti, Flavio; Malembic-Maher, Sylvie; Salar, Pascal; Bosco, Domenico; Marzachì, Cristina
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1695744
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