Increasing vineyard biodiversity by indigenous Saccharomyces cerevisiae strains spreading: yeast persistence and effect on spontaneous grape must fermentations

Background: Recent studies indicate that S. cerevisiae strain biodiversity in vineyard is highly variable and seems to be influenced not only by grapevine varieties but also by pesticide treatments. High biodiversity level is necessary to guarantee spontaneous fermentation that recently have been re-evaluated both for positively influencing sensorial characteristics of wine and for supporting a more “natural” management of wine-making process. Objectives: The aim of this work was to increase yeast biodiversity by spraying five indigenous S. cerevisiae strains on grape vineyards and to evaluate their persistence and colonizing ability. Methods: From a collection of vineyard yeasts isolated in the area of “Prosecco di Conegliano-Valdobbiadene” DOCG five strains were chosen and sprayed on two vineyard of the same wine-making region: one was cultivated using conventional practices and the other grown under organic farming methods. Bark and leaf samples were collected and added to synthetic must. After fermentation yeasts were isolated and mtDNA analysis was performed to identify the inoculated strains. Conclusions: The presence of the introduced strains was monitored 10 days and 2 months after yeast culture spray. Results on strain ability to colonize grapevine bark are also reported.