Comparison of Saccharomyces cerevisiae populations from different appellations of origin and grape varieties by microsatellite analysis

Abstract

One hundred ninety two grape samples were collected during the 2006 harvest season in the Vinho Verde (grape varieties: Arinto, Alvarinho, Avesso, Loureiro, Touriga Nacional) Bairrada (grape varieties: Arinto, Baga, Castelão Francês, Maria Gomes, Touriga Nacional) Alentejo (grape varieties, Aragonês, Trincadeira, Touriga Nacional), Terras do Sado (grape variety Castelão) Bucelas (grape variety Arinto) and Estremadura (grape varieties: Arinto, Aragonês, Castelão, Trincadeira, Touriga Nacional) appellations of origin. From the final stage of spontaneous fermentations, 2820 yeast isolates were obtained, mainly belonging to the species S. cerevisiae. An initial genetic screen, based on mitochondrial DNA restriction fragment length polymorphism (mtDNA RFLP) and/or interdelta sequence analysis, was followed by microsatellite analysis of strains with unique genetic profiles. For all loci analyzed, observed heterozygosity was three to four times lower than the expected value, probably due to a strong populational substructuring. Populational structures were identified based on the accumulation of small allele-frequency differences across six loci in groups of strains. The presented large-scale approach shows that microsatellite typing reveals a very fine population resolution of indigenous S. cerevisiae strains for the evaluation of populational differences associated to grape variety and geographical regions.