Genetic Diversity and Population Structure of Saccharomyces cerevisiae Strains Isolated from Different Grape Varieties and Winemaking Regions

Abstract

We herein evaluate intraspecific genetic diversity of fermentative vineyard-associated S. cerevisiae strains and evaluate relationships between grape varieties and geographical location on populational structures. From the musts obtained from 288 grape samples, collected from two wine regions (16 vineyards, nine grape varieties), 94 spontaneous fermentations were concluded and 2820 yeast isolates were obtained that belonged mainly (92%) to the species S. cerevisiae. Isolates were classified in 321 strains by the use of ten microsatellite markers. A high strain diversity (8–43 strains per fermentation) was associated with high percentage (60–100%) of fermenting samples per vineyard, whereas a lower percentage of spontaneous fermentations (0–40%) corresponded to a rather low strain diversity (1–10 strains per fermentation).For the majority of the populations, observed heterozygosity (Ho) was about two to five times lower than the expected heterozygosity (He). The inferred ancestry showed a very high degree of admixture and divergence was observed between both grape variety and geographical region. Analysis of molecular variance showed that 81–93% of the total genetic variation existed within populations, while significant differentiation within the groups could be detected. Results from AMOVA analysis and clustering of allelic frequencies agree in the distinction of genetically more dispersed populations from the larger wine region compared to the less extended region. Our data show that grape variety is a driver of populational structures, because vineyards with distinct varieties harbor genetically more differentiated S. cerevisiae populations. Conversely, S. cerevisiae strains from vineyards in close proximity (5–10 km) that contain the same grape variety tend to be less divergent. Populational similarities did not correlate with the distance between vineyards of the two wine regions. Globally, our results show that populations of S. cerevisiae in vineyards may occur locally due to multi-factorial influences, one of them being the grape variety.

Cellar-Associated Saccharomyces cerevisiae Population Structure Revealed High-Level Diversity and Perennial Persistence at Sauternes Wine Estates

“…A highly discriminating method based on 15 microsatellite markers specific to S. cerevisiae was used for molecular typing at the strain level. In comparison to previous studies based on other methods, such as PFGE, mtDNA RFLP, and inter-delta analysis (6,8,48), this S. cerevisiae ecological study used deep sampling and relied on the robustness of the microsatellite marker method (36,(49)(50)(51), performed with 15 loci as microsatellite markers and providing more sensitivity than previous studies. Multilocus microsatellite analysis allowed us to evaluate the genetic diversity of our population.…”

Breeding Strategy To Generate Robust Yeast Starter Cultures for Cocoa Pulp Fermentations

“…Further DNA fingerprinting to the strain level revealed in this study that each fermentation typically harbors several different S. cerevisiae strains. While this phenomenon has been described intensively for wine fermentations (56,57), the intraspecific S. cerevisiae diversity in cocoa pulp fermentations is barely documented (7). We showed that one group of closely related strains was dominant in both fermentations and therefore selected a representative strain (Y927) as a potential starter culture and as a parental strain for further breeding experiments.…”

Lager Yeast Comes of Age

“…This information was directly used to study the gene-based phenotypes, e.g., of sugar fermentations in yeast hybrids (108). The ease with which Saccharomyces strains can form viable hybrids results in hybrid formation also in natural environments (109)(110)(111)(112)(113). Based on the lack of apparent (or effective) prezygotic barriers, it has been proposed that speciation in Saccharomyces is ensured by postzygotic barriers preventing sporulation or the generation of viable spores.…”