Phylogeographical structure and conservation genetics of wild grapevine

The distribution of Vitis vinifera subsp. silvestris, the wild grapevine subspecies of Vitis vinifera L., has beendramatically reduced in its major sites of diffusion, at first by the spread, over the last 150 years, ofpathogens from North America and, more recently, with fragmentation of habitat and disbranching byhumans. In this work, 418 wild grapevine samples, belonging to 78 populations, were collected in their mainMediterranean distribution areas, including the Caucasus area, and the extent of their genetic variabilityevaluated by analysing plastid microsatellite DNA polymorphism. Results show low haplotype diversityvalue, with five haplotypes detected within the analysed populations. The highest within-population haplotypicdiversity, with the presence of all five detected haplotypes, was found in the Caucasus regions andin the central regions of Italy. The distribution of all detected haplotypes suggests the Caucasian region asthe possible center of origin of Vitis vinifera subsp. silvestris. A principal plastid lineage was found to befixed in several locations, in the Northernmost European countries and in the Southern island of Sardinia.These results draw attention to two different refugium sites in the Mediterranean basin and suggest thatconservation priority should be given to grapevine populations still preserved in hotspots of these regions.