Microbial terroir in winegrowing: revisiting the role of microbial biogeography in terroir expression

ABSTRACT The concept of microbial terroir posits that microbial biogeography pre- and post-harvest contributes to regional variation in the sensory properties of wines and some other foods. Since the introduction of this concept, the field has rapidly advanced and accumulated strong evidence that regionally distinct microbial communities contribute to characteristic wine qualities. Biogeographic patterns of vineyard microbiomes by now have been documented across all major wine-producing regions, improving our understanding of microbial sources and dispersal, as well as the abiotic and biotic factors that shape community composition. Here, we summarize recent developments in microbial terroir research in winegrowing and address common misconceptions. Spatiotemporal environmental variation influences the composition of vineyard microbial communities, and we examine the specific reservoirs and contributing drivers of this diversity. We showcase how microbial biogeography, particularly the diversity of non- Saccharomyces species, influences fermentation dynamics and resulting wine characteristics and how this expression of terroir is further impacted by the winery environment and winemaking practices. Ultimately, we identify remaining knowledge gaps and discuss potential directions for future research to better understand the ecological and functional roles of microbial communities in viticulture and winemaking.