Abstract

Humans have been making wine for thousands of years and microorganisms play an integral
part in this process as they not only drive fermentation, but also significantly influence the
flavour, aroma, and quality of finished wines. Since fruits are ephemeral, they cannot comprise a permanent microbial habitat; thus, an age-old unanswered question concerns the origin of fruit and ferment associated microbes. Here we use next-generation sequencing approaches to examine and quantify the roles of native forests, vineyard soil,
bark, and fruit habitats as sources of fungal diversity in ferments. We show that aspects of
microbial communities in harvested juice and ferments vary significantly across regions, and
that while vineyard fungi account for ~40% of the source of this diversity, uncultivated ecosystems outside of vineyards also prove a significant source. We also show that while communities in harvested juice resemble those found on grapes, these increasingly resemble fungi present on vine bark as the ferment proceeds.