Extracellular vesicles produced by several wine yeast species

Abstract

The use of species alternative to Saccharomyces cerevisiae in winemaking has been expanded during the last decade. These yeasts contribute to the diversity and fullness of wine sensory features, and are typically used in combination with S. cerevisiae, in order to ensure complete fermentation. This practice has drawn the interest in interactions between different oenological yeasts. However, yeast-yeast interactions might also be relevant in spontaneous and conventional fermentations, or in the vineyard. The field is relatively young and, although several interactions have been described and some mechanisms have been suggested, the possible involvement of extracellular vesicles has not yet been considered. In this work, production of EVs by six wine yeast species, growing in synthetic grape must, is shown. Proteomic analysis of EVs from S. cerevisiae, and Torulaspora delbrueckii showed a significant enrichment in glycolytic enzymes and cell-wall related proteins, as described for some other yeasts, as well as for S. cerevisiae under other growth conditions. The most abundant protein found in S. cerevisiae, T. delbrueckii, and Lachancea thermotolerans was the enzyme exo-1,3-ß-glucanase. Fractions enriched in EVs from a T. delbrueckii strain interfere with the growth of other wine yeast strains; but exo-1,3-ß-glucanase was not required for this activity. These findings suggest EVs may play a role in fungal interactions during wine fermentation and other aspects of wine yeast biology.