Genetic structure and differentiation in cultivated grape, Vitis vinifera L.

Abstract

222 cultivated (Vitis vinifera) and 22 wild (V. vinifera ssp. sylvestris) grape accessions were analysed for genetic diversity and differentiation at eight microsatellite loci. A total of 94 alleles were detected, with extensive polymorphism among the accessions. Multivariate relationships among accessions revealed 16 genetic groups structured into three clusters, supporting the classical eco-geographic grouping of grape cultivars: occidentalis, pontica and orientalis. French cultivars appeared to be distinct and showed close affinity to the wild progenitor, ssp. sylvestris from south-western France (Pyrenees) and Tunisia, probably reflecting the origin and domestication history of many of the old wine cultivars from France. There was appreciable level of differentiation between table and wine grape cultivars, and the Muscat types were somewhat distinct within the wine grapes. Contingency chi2 analysis indicated significant heterogeneity in allele frequencies among groups at all loci. The observed heterozygosities for different groups ranged from 0.625 to 0.9 with an overall average of 0.771. Genetic relationships among groups suggested hierarchical differentiation within cultivated grape. The gene diversity analysis indicated narrow divergence among groups and that most variation was found within groups (approximately 85%). Partitioning of diversity suggested that the remaining variation is somewhat structured hierarchically at different levels of differentiation. The overall organization of genetic diversity suggests that the germplasm of cultivated grape represents a single complex gene pool and that its structure is determined by strong artificial selection and a vegetative mode of reproduction.

Linkage disequilibrium in wild French grapevine, Vitis vinifera L. subsp. silvestris

“…It can potentially be linked to population history, particularly recent bottlenecks. At the end of the nineteenth century, wild grapevine underwent a drastic reduction in diversity, owing to the disease-causing agents mildew and phylloxera , as shown by the relative genetic diversity deficit observed in wild grapevine compared to cultivated grapevine (Aradhya et al, 2003;Grassi et al, 2003). Our results also reveal such a deficit.…”

Fruit skin color and the role of anthocyanin

“…The grapevine species is a representative of the genus Vitis and has a disomic inheritance with 2n = 38 and a relatively small genome of 475 Mbp (Lodhi and Reisch 1995;Aradhya et al 2003). Grape skin color is an important factor both biologically and economically, since the quality of grape berries greatly depends on skin color, which greatly affects market prices and the wine industry (Koshita et al 2011).…”

Evolution of the VvMybA gene family, the major determinant of berry colour in cultivated grapevine (Vitis vinifera L.)

“…The diffusion of grapevines from Transcaucasus naturally led to an East-to-West pattern of colonization, following human migrations (Mc Govern, 2003). Furthermore, propagation by cuttings, generation overlap and possible secondary domestication events, as well as hybridization with sympatric wild relatives (Levadoux, 1956), led to a very complex pattern of admixture (Aradhya et al, 2003;Arroyo-Garcia et al, 2006). Although nuclear and chloroplastic microsatellite markers helped to resolve questions about the grape genetic structure and cultivar evolution (Arroyo-Garcia et al, 2006;This et al, 2006), the molecular bases of trait adaptation are still poorly investigated in non-model organisms.…”