Grape terpenoids: flavor importance, genetic regulation, and future potential

Terpenes significantly affect the flavor and quality of grapes and wine. This review summarizes recent research on terpenoids with regard to grape wine. Although, the grapevine terpene synthase gene family is the largest identified, genetic modifications involving terpenes to improve wine flavor have received little attention. Key enzyme modulation alters metabolite production. Over the last decade, the heterologous manipulation of grape glycosidase has been used to alter terpenoids, and cytochrome P450s may affect terpene synthesis. Metabolic and genetic engineering can further modify terpenoid metabolism, while using transgenic grapevines (trait transfer to the plant) could yield more flavorful wine. We also discuss traits involved in wine aroma quality, and the strategies that can be used to improve grapevine breeding technology.