Biochemistry of grape berries: post-genomics approaches to uncover the effects of water deficits on ripening

Dissertation presented to obtain the Ph.D degree in Biochemistry, Plant Physiology

Grapevine (Vitis vinifera L.) is one of the most important fruit crops worldwide. In Europe, high-quality wine producing areas are traditionally non-irrigated. However, irrigation has become a wide-spread agronomical practice to overcome the deleterious effects of drought, high temperature and high evaporative demand that vines can be exposed to during the growing season. This is particularly true in the Mediterranean area, where the foreseen scenario predicts that water deficit may become a limiting factor in wine production and quality. Paradoxically, the imposition of mild to moderate water deficit (WD) via e.g. water deficit irrigation has been regarded as an agronomical tool that manipulates berry sensory characteristics, while maintaining yield. Grape berries, which are described as non-climacteric fruits, undergo a complex biochemical suite of alterations during development and ripening that remain poorly understood, including the molecular events that control the onset of ripening. At harvest, grape berry quality is largely dependent on the sugar/acids balance within the berry flesh, and on phenolic compounds (e.g. flavonoids) in the grape skin, which contribute to wine colour, aroma and flavour.(...)

PhD Fellowship SFRH/BD/30344/2006 from ‘Fundação para a Ciência e a Tecnologia’ (FCT) and ‘Fundo Social Europeu’ in the scope of ‘Quadro Comunitário de Apoio’.