Genetic diversity of yeasts isolated from Eurasian populations of Vitis vinifera ssp. Sylvestris (Gmelin) Hegi

Vitis vinifera L. ssp. Sylvestris (Gmelin) Hegi is the only ancestral grapevine species in the Euroasiatic area and it is recognized as the dioecious parental generation of today’s cultivars. It constitutes an important phytogenetic resource, but urbanization and industrialization of territories, climatic change and the arrival in Europe of pathogens and pests have led it to be included on the IUCN Red List of Threatened Species in 1997. Although numerous studies about the current health status of this species have been carried out, at best of our knowledge, no studies on microbial populations of grape-berry surfaces have been done. The present work has been focused on the study of yeast occurrence and diversity on grape-berries collected from wild vines (V. vinifera ssp. Sylvestris). Final outputs have allowed: i) to obtain precise information about yeast communities; ii) to provide an objective framework for the classification of the broadest range of species according to their extinction risk; iii) to select actractive yeast strains for their biotechnological potential, offering new opportunities to winemakers. Grape-berries from wild vines were carefully harvested in Azerbaijan, Georgia, Italy, Romania and Spain, in different sites for each country. In all, 3180 epiphytic and endophytic yeast colonies were isolated and identified as belonging to 50 species, including Saccharomyces cerevisiae, by 26S rDNA D1/D2 domains and ITS region sequencing. Isolates belonging to S. cerevisiae were also analysed by SSR-PCR obtaining 163 different genotypes. Moreover, despite of some species appeared in all countries, yeast ecology differed in the sampled regions. This study highlights the biodiversity potential of pristine environments that still represent a fascinating source for the investigation of gene evolution and that offer a platform to face common problems in winemaking.