Saccharomyces cerevisiae biodiversity in the vineyards of “Zona Alta del Río Mendoza” Argentinean wine region.

MERCADO L.; CIKLIC I.; MASUELLI R.; COMBINA M.

Paris, Francia

Simposio; 27th International Specialized Symposium of Yeast “Yeasts for health and biotechnologies” (ISSY); 2009

International Yeast Comission

The “Zona Alta del Río Mendoza” (ZARM) constitutes one of the most important wine regions of Argentina, where many cellars are placed devoted to the production of quality wines. Malbec grapes find in this region the optimum conditions for the expression of their quality attributes. Saccharomyces populations from vineyards distributed within the ZARM wine region were evaluated in the present work in order to realize biodiversity and molecular relationships among them. Additionally, participation of vineyard yeast in spontaneous fermentation performed in winery was also evaluated. Ten isolation sites were selected in 8 vineyards where mature healthy Malbec grapes were sampled. Fermenting musts were also sampled in six different cellars once each vineyard was harvested and processed. Approximately 1020 Saccharomyces were isolated and characterized by combination of PCR interdelta and RFLP mtDNA molecular patterns. The results obtained showed a specific Saccharomyces population for each vineyard. Two types of vineyard biodiversity were observed: high polymorphism and low polymorphism. The highly polymorphic vineyards, 5 over 8, harboured more than 20 different patterns. These patterns were randomly distributed, including each sampling site a unique sub-population constituted for 1 to 12 patterns and sharing a few molecular patterns among them. More than 85% of the patterns found in these vineyards exhibit a unique character, so they were only detected in an only vineyard. Two vineyards were less polymorphic, with only 9 and 10 different molecular patterns detected. Some patterns showed a generalized presence in these vineyards and they matched with molecular patterns exhibited by commercial yeast strains commonly used in this wine region. These results indicated that vineyards located close to winery, as was the case of the less polymorphic vineyards, suffer modifications of its diversity by replacing native yeast population with commercial strains. On the other hand, molecular relationships were evaluated by constructing dendrograms where yeasts molecular patterns from vineyard and their corresponding industrial fermentation were included. In general terms, clusters included isolates from the different sampling sites and also isolates from fermentation. Although not many vineyard Saccharomyces participate in the spontaneous fermentations, close relation was verified among both types of isolates.