Characterizing vineyard-specific differences in Pinot Noir grape composition in relation to soil properties and rhizosphere microbial communities.

BACKGROUND: Grape berry chemical composition is closely linked to wine quality and provides important information for vineyard management. However, the relationships between berry composition, vineyard soil conditions and rhizosphere microbial communities remain insufficiently understood. This study evaluated the associations among soil physicochemical properties, rhizosphere bacterial and fungal communities, and berry amino acid and phenolic composition in two adjacent Pinot Noir (Vitis vinifera L.) vineyards over two vintages. RESULTS: Individual berry amino acids and phenolic compounds showed clear vineyard differences. Under this two-vineyard field design, the vineyard with higher soil pH and cation exchange capacity (CEC) had higher berry amino acid concentrations (e.g., arginine and glutamine), whereas the vineyard with higher exchangeable Mn showed higher concentrations of phenolic compounds (e.g., catechin, epicatechin, and delphinidin-3-glucoside). Integrated analyses further indicated that soil pH, cation exchange capacity, exchangeable Mn and bacterial community structure were among the variables most closely associated with vineyard differences in berry composition. Rhizosphere bacterial community structure was associated with berry amino acid composition, whereas fungal communities showed weaker relationships with berry composition. CONCLUSION: This field-based case study shows that vineyard-specific differences in Pinot Noir grape amino acid and phenolic composition co-varied with soil physicochemical properties and rhizosphere bacterial community structure. Soil pH, CEC, exchangeable Mn, and bacterial community structure were identified as candidate variables associated with grape compositional differences. The results provide a basis for future mechanistic studies integrating soil nutrient dynamics, vine nutrient status, microbial functional traits, and grape metabolite development. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.