Biology subjects

Griggs, R. G.

Publications and source records attributed to Griggs, R. G..

3 recordsLinked to original sources

bioRxiv2025

Spatial heterogeneity and microbial terroir: balancing dispersal limitation and cultivar as drivers of microbial diversity in viticulture

The microbial communities inhabiting grapevines and wines exhibit spatiotemporal patterns linked to region, climate, and cultivar. However, the degree of spatial heterogeneity within and between vineyards and its relationship to cultivar-associated biodiversity selection has not been studied previously. We combined high-density sampling of grapevine microbiota (N = 230) with spatial modeling and satellite imagery in two experiments: (i) two monoclonal Chardonnay vineyards to examine spatial heterogeneity in a genetically homogenous population; and (ii) three old-vine vineyards interplanted with mixed cultivars to investigate the relative effects of spatial distance and cultivar on the microbiota. Contrary to expectations based on monoclonal vineyards, cultivar effects were not apparent in mixed-cultivar vineyards. Instead, we demonstrate extensive spatial variation in the bacterial and fungal communities inhabiting individual grapevines and vineyards, and that community similarity is correlated with spatial distance within and between vineyards. This suggests that dispersal limitation may play an important role in shaping grapevine microbiota, as well as cumulative diversity within the vineyard ecosystem (gamma diversity), with implications for both plant health and wine quality. Spatial models can identify abnormalities in microbial communities, such as contaminant sources within vineyards, and future studies examining microbiota in agricultural settings should account for spatial variation within the study design, e.g., by sufficiently dense spatial sampling or collection of grape musts to avoid undersampling bias. These findings add to the complicated story of microbial biogeography associated with winegrowing and wine quality (microbial terroir), highlighting the roles of dispersal and potential microclimate effects in agricultural settings.

microbiology↗

bioRxiv2025

The Genetic Basis of Microbiome Recruitment in Grapevine and its Association with Fermentative and Pathogenic Taxa

O_LIWhile grapevine is an exceptional perennial model for studying host-microbiome interactions, the host genomes role in microbiome assembly is often masked by environmental factors. This research provides a first insight into the genetic mechanisms shaping berry-associated microbial communities. C_LIO_LIUsing QTL mapping in a newly established population of 140 F1-progeny grapevine genotypes in a complete random block design, we were able to control abiotic effects and investigate how the host genome influences grape berry-associated bacterial and fungal communities. C_LIO_LIWe identify significant associations between various microorganisms and the grape genome, including pathogenic fungi such as Botrytis spp. and fermentative yeasts such as Saccharomyces cerevisiae. Many of these taxa map to the same genetic loci associated with plant immune responses, suggesting that specific genetic loci broadly influence microbial community assembly in fruits. C_LIO_LIOur findings demonstrate that grapevine genetics significantly shape the microbiome, even under varying environmental conditions; moreover, that broad, rather than known symbiont-specific mechanisms control microbial colonization of fruit, revealing an emergent "domino" effect with implications for plant-fungal-bacterial interactions. We provide a framework for understanding genotype-microbiome interactions in perennial plants, enabling future targeted experiments to establish causal relationships in microbiome recruitment and offer a potential avenue for breeding programs advancing sustainable viticulture. C_LI

microbiology↗

bioRxiv2025

A tale of two vineyards: parsing site-specific differences in bacterial and fungal communities of wine grapes from proximal vineyards, and their changes during processing in a single winery

Wine is a microbial product, naturally transformed through fermentation by a consortium of fungi and bacteria that originate from the vineyard and the cellar, in addition to any microorganisms that are intentionally inoculated. Previous work has shown that grapevine-associated microbiota follow distinct biogeographic patterns, associated with climate and soil properties, and that even neighboring vineyards can harbor distinct microbial communities, but it is unclear whether these differences persist when controlling for variations in farming practices, cultivar, and climate, and whether site-specific microbial profiles change during processing in the winery. Here we investigated the bacterial and fungal microbiota of fruit pre- and post-harvest from two nearby vineyards planted to a single variety, geographically close to one another, and farmed the same way, and then processed in a single winery. These communities subtly changed during processing yet retained distinct site-specific signatures, indicating a partial contribution of the winery environment to the microbiota of grape must and juice pre-fermentation. We also profiled the microbiota of key microbial sources in the winery environment, including fruit flies and processing equipment, demonstrating that the microbiota at these sites reflect contact with plant material, harbor communities distinct from fruit, and appear to partially contribute to the fermentation assemblage, especially via the contribution of fermentative yeasts that are rare or missing in the vineyard environment. These results bolster previous reports of site-specific microbial signatures in winegrowing and make a first estimation of the changes to the grape-associated microbiome during early processing. ImportanceNative wine fermentations are driven by microbes carried over from the vineyard or introduced in the winery. In this study, we tracked the microbiome dynamics of wine fermentations from two Chardonnay vineyards planted in close proximity to examine the relative contribution of vineyard- and winery-resident microbiota on microbial succession during wine fermentation. By tracking microbial changes from vineyard to winery, we show that the winery environment, including processing equipment and fruit flies, contributes to the fermentation microbiome but does not override vineyard-specific microbial differences. These findings support the concept of microbial terroir and highlight the importance of vineyard microbiomes in shaping wine fermentation. This work advances our understanding of how microbial diversity influences wine production and provides insight into the ecological dynamics of fermentation. By identifying key microbial sources and their contributions, this study lays the groundwork for future microbiome research in viticulture and wine making.

microbiology↗