Grape-derived flavour compounds and some flavour precursors modified during fermentation, wine evolution and ageing, are fundamental in determining the organoleptic parameters used to define wine quality as the aromatic quality, persistency and complexity are wine characteristics that may influence consumer choice. Although hundreds of secondary metabolites that potentially contribute to wine flavour have been detected in grapes, the knowledge of the biosynthesis of many of these compounds is not well understood and only a few genes involved in flavour pathways have been functionally characterised. The aim of this research is the selection of grape aroma candidate genes by analysis of correlation between gene expression and aroma accumulation trends during berry development of ‘Aleatico’, ‘Moscato bianco’ and ‘Sangiovese’ grapevine varieties cultivated in Tuscany. Samples of flowers and berry at different developmental stages, from fruit set to technological ripening, have been analysed for their aroma content and the expression of some genes predicted to be involved in grape flavour pathways. The aroma compounds have been extracted by SPE and SPME procedures and analysed by GS-MS, while the expression of characterised grape aroma genes and some candidate genes have been analysed by real-time RT-PCR. The analysis reveal that monoterpenes and benzene derivatives are mostly synthesised in flowers and in ripening berries but also in green berries, C13-norisoprenoids are mainly synthesised during ripening, while sesquiterpenes are largely synthesised in flowers [1, 2, 3]. Among the analysed genes, some showed a peak of expression in flowers, while others are expressed during berry ripening [1, 2, 3]. In particular, a candidate sesquiterpene synthases was expressed in flowers of all three analysed varieties and showed a good correlation with farnesene accumulation in flowers buds and open flowers, a putative monoterpene synthase that is expressed when linalool accumulates during ripening, another putative monoterpene synthase that is expressed when geraniol accumulates during ripening, and a putative epoxidase with an expression that matched with linalool oxides accumulation during ripening. In conclusion, the analysis of correlations between aroma accumulation and gene expression has allowed the identification of candidate genes potentially involved in grape aroma compound biosynthesis on which has been focused the functional characterisation by analysis of enzymatic activity of recombinant proteins.
Aroma accumulation trends during berry development and selection of grape aroma candidate genes suitable for functional characterization
D'ONOFRIO, CLAUDIO
2010-01-01
Abstract
Grape-derived flavour compounds and some flavour precursors modified during fermentation, wine evolution and ageing, are fundamental in determining the organoleptic parameters used to define wine quality as the aromatic quality, persistency and complexity are wine characteristics that may influence consumer choice. Although hundreds of secondary metabolites that potentially contribute to wine flavour have been detected in grapes, the knowledge of the biosynthesis of many of these compounds is not well understood and only a few genes involved in flavour pathways have been functionally characterised. The aim of this research is the selection of grape aroma candidate genes by analysis of correlation between gene expression and aroma accumulation trends during berry development of ‘Aleatico’, ‘Moscato bianco’ and ‘Sangiovese’ grapevine varieties cultivated in Tuscany. Samples of flowers and berry at different developmental stages, from fruit set to technological ripening, have been analysed for their aroma content and the expression of some genes predicted to be involved in grape flavour pathways. The aroma compounds have been extracted by SPE and SPME procedures and analysed by GS-MS, while the expression of characterised grape aroma genes and some candidate genes have been analysed by real-time RT-PCR. The analysis reveal that monoterpenes and benzene derivatives are mostly synthesised in flowers and in ripening berries but also in green berries, C13-norisoprenoids are mainly synthesised during ripening, while sesquiterpenes are largely synthesised in flowers [1, 2, 3]. Among the analysed genes, some showed a peak of expression in flowers, while others are expressed during berry ripening [1, 2, 3]. In particular, a candidate sesquiterpene synthases was expressed in flowers of all three analysed varieties and showed a good correlation with farnesene accumulation in flowers buds and open flowers, a putative monoterpene synthase that is expressed when linalool accumulates during ripening, another putative monoterpene synthase that is expressed when geraniol accumulates during ripening, and a putative epoxidase with an expression that matched with linalool oxides accumulation during ripening. In conclusion, the analysis of correlations between aroma accumulation and gene expression has allowed the identification of candidate genes potentially involved in grape aroma compound biosynthesis on which has been focused the functional characterisation by analysis of enzymatic activity of recombinant proteins.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
