Yeast diversity in Vitis labrusca l. Ecosystems

Abstract

Although there are detailed studies on the microbiota of Vitis vinifera L. grapes, little is known about the diversity of yeast communities present in non-vinifera Vitis ecosystems (i.e., grapes and spontaneously fermenting grape musts). Potentially scientific and/or enological valuable yeast strains from these non-vinifera Vitis ecosystems might never be isolated from V. vinifera L. Using a standard culture-dependent strategy, we studied the population of yeast species during initial stages of spontaneous fermentation of V. labrusca L. (Isabella) grape musts. Rare non-Saccharomyces yeast species were recognized in Isabella, including Candida azymoides, Pichia cecembensis, Candida californica, Candida bentonensis, Issatchenkia hanoiensis and Candida apicola. Interestingly, P. cecembensis, not previously recognized in V. vinifera grapes or musts, was also found in V. labrusca L. grapes in Portugal (Azores Archipelago). Thus, this yeast species could be specifically associated with V. labrusca L. grapes, regardless of their geographic origin and/or the associated human interventions. Moreover, I. hanoiensis, a yeast species rarely isolated in V. vinifera grapes, was also identified in V. labrusca ecosystems from Argentina and Portugal. These results suggest that specific Vitis-microbial interactions may underlie the assembly of specific grape vine yeast communities. Also interestingly, some yeast genera commonly isolated from V. vinifera ecosystems (e.g., Hanseniaspora, Torulaspora and Metschnikowia) were rarely identified and almost never dominated the yeast communities in the V. labrusca L. musts we analyzed. Our results reinforce the research interest in biodiversity and extraordinary wine yeasts in ecological niches alternative to traditional V. vinifera ecosystems.