Different indigenous yeast populations in spontaneously fermenting musts from V. vinifera L. and Vitis labrusca L. grapes harvested in a shared terroir.

RAYMOND EDER, MARÍA L.; ROSA, ALBERTO L.; CONTI, FRANCISCO

Bariloche

Congreso; International Specialized Symposium on Yeasts.; 2018

Yeast communities associated with Vitis vinifera L. ecosystems (i.e., grapes and fermenting grape musts) have been widely characterized. Less is known, however, about yeast communities present in Vitis non-vinifera ecosystems. Moreover, there are no comparative studies concerning yeast communities in grapes from V. vinifera L. and non-vinifera Vitis species in vineyards from a shared terroir. In our work, we have used culture-dependent strategies, phenotypic analyses, and molecular genotyping, to study the most representative yeast species and strains present in spontaneously fermenting musts of grapes harvested from neighboring V. vinifera L. (cv. Malbec) and V. labrusca L. (cv. Isabella) vineyards. Analyses of a small number of isolates from early stages of fermentation showed that Hanseniaspora uvarum was the predominant non-Saccharomyces species in both Malbec and Isabella ecosystems. Hanseniaspora vineae, Metschnikowia pulcherrima and Torulaspora delbrueckii, yeast species commonly found in V. vinifera L. grape musts, were isolated only from the Malbec ecosystem. Candida californica, on the other hand, was only isolated from the Isabella ecosystem. Phenotypic analyses of four randomly selected H. uvarum, Starmerella bacillaris and Sacharomyes cerevisiae isolates, as well as microsatellite genotyping of S. cerevisiae isolates from each Malbec and Isabella grape musts, suggest that V. vinifera L. and V. labrusca L. ecosystems could potentially harbor yeast strain populations that are specific to each Vitis species. It is tempting to speculate that specific as yet unknown characteristics of different Vitis species could underlie the assembly of communities of associated yeast species and strains from a given species. We propose that non-conventional Vitis ecosystems offer opportunities to look for unique yeast strains of potential relevance for the winemaking industry.