Transcriptomics Provides a Genetic Signature of Vineyard Site and Offers Insight into Vintage-Independent Inoculated...

Area of Science:

• Microbiology
• Genomics
• Enology

Background:

• Wine fermentation involves a complex microbiome influenced by vineyard origin.
• Understanding the role of this microbiome in wine quality and regional distinctiveness is crucial for the wine industry.

Purpose of the Study:

• To investigate the relationship between microbial DNA in grape must and active gene expression during primary fermentation.
• To identify vineyard-specific genetic signatures that may influence fermentation outcomes and wine characteristics.

Main Methods:

• Ribosomal DNA amplicon sequencing of grape musts.
• RNA sequencing of eukaryotic transcripts during primary fermentation of inoculated wine yeast (Saccharomyces cerevisiae RC212).
• Analysis of microbial community composition and gene expression patterns across 15 vineyards over two vintages.

Main Results:

• Fungal organisms detected by DNA sequencing were largely inactive during primary fermentation and did not significantly affect the inoculated yeast's gene expression.
• Unique genetic signatures, including Saccharomyces cerevisiae gene expression patterns related to nitrogen, sulfur, and thiamine metabolism, were associated with specific vineyard sites and regions.
• These genetic signatures were predictive of vineyard site and region, offering insights into environmental factors impacting fermentation.

Conclusions:

• The presence of microbial DNA in grape must does not necessarily indicate active participation in primary wine fermentation.
• Vineyard site and region exert an influence on fermentation through specific genetic signatures in the inoculated yeast.
• These findings provide a basis for understanding how vineyard environment contributes to regional wine distinctiveness and fermentation outcomes.