Analysis of the expression of terpene synthase genes in relation to aroma content in two aromatic Vitis vinifera varieties

Abstract

Grape (Vitis vinifera L.) flavour management in the vineyard requires knowledge of the derivation of individual flavour and aroma characteristics. Some of the most prevalent wine grape aroma constituents are terpenoids and this study represents a wide report about grape terpene synthase (TPS) gene transcript profiling in different tissues of two aromatic grapevine varieties, particularly flowers and developing berries, correlated with the accumulation patterns of free aroma compounds. All investigated genes belonging to the TPS-a and TPS-b subfamilies reached the highest expression in accordance with the peak of accumulation of the respective compounds. In the TPS-g subfamily, only one of the genes characterised for linalool synthases showed major transcript abundance in ripening berries, whereas the only geraniol synthase had a peak of expression in green berries and at the beginning of ripening, when geraniol concentration started to increase and overcome the linalool concentration. The genes identified in this study as being mainly responsible for linalool and geraniol synthesis during berry development, and the phenological phases in which they are mostly expressed, should be of interest to viticulturists and wine makers to improve decision making along the chain of production.

Study of the terpene profile at harvest and during berry development of Vitis vinifera L. aromatic varieties Aleatico, Brachetto, Malvasia di Candia aromatica and Moscato bianco

“…). The absence of a unique and clear trend of the ratio among geraniol, linalool and α ‐terpineol derivatives in the four varieties, confirms the independence of the biosynthesis of these three important aromatic compounds, as previously supported by gene expression analysis …”

“…B). Considering that at the end of ripening, the water accumulation is weak or absent, and that there may also be a loss of water as a consequence of over‐ripening, the decrease in aroma concentration detected during the last period of ripening could be due to an increase in the degradation rate, or a possible decrease in biosynthesis, as previously highlighted by gene expression analysis …”

“…These aroma substances are synthesised throughout the berry's development and are qualitatively and quantitatively influenced by environmental and agricultural factors …”

Influence of vineyard altitude on Glera grape ripening (Vitis vinifera L.): effects on aroma evolution and wine sensory profile

“…Several studies suggest that the period between véraison and harvest is the most important for biosynthesis, accumulation and preservation of grape aroma compounds. The result of the present study revealed that, at both sites and in both years, the synthesis of all the three classes of volatiles started before véraison, indicating that the activation of their biosynthetic pathways can occur in the first stages of berry development …”

Influence of cluster thinning and girdling on aroma composition in ‘Jumeigui’ table grape

“…Similarly, the transcript abundance of VvCSLinNer gene, which was reported as the key gene involved in linalool accumulation 8,12 , was very low throughout the ripening period except the onset of véraison, but was uncorrelated with linalool accumulation. The similar low expression levels of VvCSLinNer gene were found in ripening berries of other cultivars 11,43,44 . Therefore, these inconsistent reports on the same gene might due to the different cultivars and climatic conditions.…”