We Prefer Them Old: Epigenetic Control of Wine Quality in Response to Grapevine Age

Wines produced from ‘young’ grapevines allegedly lack the complexity and quality of ‘old’ vine wines. There is increasing evidence that epigenetic mechanisms such as DNA methylation contribute to important agronomic traits. While genetic traits are fixed during the life cycle of an individual, environmental exposure and stochastic processes during development lead to changes in methylation, which can induce new phenotypes. This study aims to understand how age induced methylation variation contributes to changes in wine chemical composition. Sensory assessment of the aroma profile of fruit from last vintage from young (25 years old) and old (125+) vines was undertaken to determine which aroma attributes provide enhanced quality to wine from old vines. Using a systems biology and NGS approach, we investigated the grapevine genome, transcriptome and methylome to understand the non-genetic effect that vine age has on wine quality. Bisulfite NGS and comparative analyses were carried out to identify differentially methylated genes and their effect on biosynthesis pathways. Candidate gene expression changes were then confirmed using NGS RNAseq.