Tesi di dottorato di ricerca
DE LORENZIS, GABRIELLA
CHARACTERIZATION OF AROMA BIOSYNTHETIC PATHWAYS IN VITIS VINIFERA
Settore scientifico disciplinare
Corso di studi
SCIENZA DELLE PRODUZIONI VEGETALI ECO-COMPATIBILI
tutor Dott. D'Onofrio, Claudio
- volatile compounds
- terpene synthase
- Moscato bianco
Data inizio appello
Data di rilascio
Varietal aroma plays a significant role in defining the wine aroma, but there are insufficient knownledges about their biosynthesis and evolution during berries development, especially in herbaceous phase. To know the evolution of aromatic compounds during all phases of berries development it is crucial for understanding the way to manage the grapes aromatic potential in the vineyard for improving wine aromatic profile. <br>The present work describes the changes in terpenes (monoterpenes and sesquiterpenes), C13-noriprenoids, C6-alcohols and benenoids levels in flower buds, flowers and during berries development from fruit set to ripening, of two different Vitis vinifera L. cultivars: “Moscato bianco” and “Sangiovese”. In the same samples the expression patterns of some flavour candidate genes were measured in order to study the correlation between these putative genes and volatile compounds accumulation.<br>Another aspect of this reaserch has been focused on the effects of vine canopy microclimate on berries aroma composition: in “Ciliegiolo” and “Sangiovese” cultivars basal leaves have been removed at fruit set or at véraison to valuate possible differences in grape flavour conten.<br>The aromatic compounds were detected in flower buds, flowers and in all stages of Moscato bianco and Sangiovese berry development. Aromatic compounds content reached the highest value during flowering and at full maturation. The flavor profile of Moscato bianco grapes appeared mainly characterized to compounds monoterpenes, while the presence of other classes of aroma identified (sesquiterpenes, norisoprenoids, aliphatic alcohols and benzene derivatives) was not very relevant; during flowering we observed the highest value of sesquiterpenes content. The flavor profile of Sangiovese grapes appeared mainly characterized by monoterpenes and norisoprenoids; such as in Moscato bianco, we have been observed the highest accumulation sesquiterpenes in flowers. The terpenes content in flowers and during berry ripening coincided with expression increase of genes involved in the biosynthesis of monoterpenes and sesquiterpenes. Abundance of terpene synthases transcripts (monoterpenes and sesquiterpenes synthase), detected in flower buds and open flowers and showed hight correlation with monoterpenes and sesquiterpenes contents in preflowering and during flowering, could be involved in the formation of flower volatile compounds. While terpene synthases transcripts detected after flowering could be involved in the formation of berry volatile compounds. Absence of sesquiterpenes detected during ripening suggested a specific role of these terpene synthase in moterpenes formation of ripe berry. Based on gene expression results, among gene showing a good correlation between aromatic content and gene expression, we selected 3 genes to focus functional characterization analysis. <br>Leaf removal during fruit set in both Sangiovese and Ciliegiolo lead and increase in monoterpenes and especially in C13-norisoprenoids aroma. C13-norisoprenoids increase following leaf removal confirmed the hypothesis that these compounds derive from carotenoids degratation, favoured by sunshine. These results contribuited to establish that vine canopy management is effective in the modulation of aroma berry composition and consequently in wine sensory quality.
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