Aroma accumulation trends during berry development and selection of grape aroma candidate genes suitable for functional characterization

Abstract

Grape flavour management in the vineyard requires knowledge of the derivation of individual flavour and aroma characteristics and the effects that different concentrations and interactions between these compounds have on flavour potential. But, although hundreds of secondary metabolites that potentially contribute to wine flavour have been detected in grapes, knowledge of the biosynthesis of these compounds and the effects of growth conditions on their accumulation is not well understood. The aim of this research is the discovery of candidate genes thought to contribute to the volatile profiles of grapes by an analysis of correlations between flavour compound concentration and gene expression levels in flowers and during berry development of ‘Aleatico’, ‘Moscato bianco’ and ‘Sangiovese’ cultivated in Tuscany. The results demonstrate that the analysis of correlation among flavour compounds and gene expression patterns in flower and during berry development is a powerful tool for selection of most promising candidate genes involved in terpene biosynthesis pathways. The analysis of the above correlations in ‘Aleatico’, ‘Moscato bianco’ and ‘Sangiovese’ has allowed us to identify a putative a-farnesene synthase, a candidate linalool synthase gene expressed in flowers and during berry ripening and a putative geraniol synthase gene expressed during berry ripening. We are now working towards the functional characterization of these Vitis vinifera genes involved in terpene pathways.