Integrating Functional Genomics With Salinity and Water Deficit Stress Responses in Wine Grape - Vitis Vinifera

Abstract

Wine grape (Vitis vinifera) is the world’s most important fruit crop both in terms of crop production and economic value. For most crops, water deficit stress has negative implications for production and quality. For wine grape, however, vegetative growth is more sensitive to water-deficit stress than fruit growth. Thus, moderate water-deficit can positively influence the quality of wine produced from grapes harvested from vines grown under regulated (water) deficit irrigation (RDI) and partial root zone drying (PRD) conditions. However, the interaction between water deficit stress and berry composition is complicated by the ability to accurately measure water potential under field conditions and can be influenced by many parameters including timing of stress application within a season and across several seasons, grapevine variety and canopy, leaf to fruit ratio, and soil structure. The mechanistic basis for observed quality differences are poorly understood. However, recent studies using integrated transcriptome and metabolome data sets have revealed potential underlying changes in gene expression and determinants of fruit characteristics that explain the major effects that water deficit treatment can be expected to have on wine quality. Major responses include gene expression changes resulting in alterations in sugar content, anthocyanin accumulation, and decreased organic acid accumulation