Can transcriptomics shed light on the "old-vine" character of wines?
In South Africa, there is a newfound interest in old vineyards, and the exceptional wines produced from them. These wines are generally accepted as having more depth and complexity than young-vineyard wines, thus the term old vine tends to be used on wine labels as an indication of a superior, high-quality wine. However, there is only anecdotal evidence that these wines are truly of a higher standard. This study is the first scientific research into the so-called old-vine wine character, aiming to determine any significant differences in gene expression in leaves and berries of young and old clonal vines, at the time of harvest. Gene expression of 40-year-old and 7-year-old vines, growing in a commercial 'Pinotage' vineyard, and used for the production of such premium wines, was analysed as the first step towards elucidating the origins of the old-vine character. RNA-seq analysis identified 925 genes differentially expressed between young and old vines. Many of these transcripts are involved in metabolic pathways active during fruit ripening. A general trend was observed towards delayed berry ripening in old vines. Berries of these vines also had a lower sugar concentration and higher titratable acids at the time of harvest compared with young-vine berries. Collectively, these results would suggest that berries of old vines take longer to ripen, possibly allowing for the accumulation of volatile aromas that influence berry flavour.
Coetzee, B., Maree, H.J. and Burger, J.T. (2019). Can transcriptomics shed light on the "old-vine" character of wines?. Acta Hortic. 1248, 487-496
RNA-seq, differential gene expression, grapevine, Pinotage, berry ripening