The overall goal is to obtain mechanistic understanding of how early leaf removal in grapevine (ELR) impacts grape quality and plant production by integratingphysiology,metabolomicsandtranscriptomicstools. The hypothesis is that ELR will activate the plant defense system through jasmonates biosynthetic pathway as response to abiotic stress induced by the vine canopy management techique. In addition, ELR will modify the biosynthesis of flavonoids through the early activation of the abscisic acid (ABA) pathway as consequence of the ELR induced-stress, enhancing color compounds accumulation, particularly the PA. The outright knowledge of the biochemistry patterns and accumulation of GSM will unveil potential agronomic strategies to improve the quality of grapevine produced in cool climates.Specific aims are to:Aim1.Evaluate photosynthetic capacity of the grapevine under ELR in red cultivars (Merlot and Pinot noir) over twogrowing seasons.Aim2. Study the color specialized metabolome and its association with abiotic stress markers (ABA, JA, SA, IAA, GA3,) as a resilience response.Aim3. Assess the transcriptional regulation ofphenylpropanoid-related enzymes (i.e. tannin polymer enzymes: leucoanthocyanidin reductase (LAR) and anthocyanidin reductase (ANR); and two transcription factors (MybPA1 and MybPA2) as result of abiotic stress(Figure 1).