Effects of mesoclimate and microclimate variations mediated by high altitude and row orientation on sucrose metabolism and anthocyanin synthesis in grape berries

Climate change and extreme weather pose significant challenges to the traditional viticulture regions. Emerging high-altitude grape-producing regions with diverse orientations have shown great potential in coping with this challenge. Stable, high-quality wine grape production may be achieved by synchronizing the meso- and microclimate. To clarify the role of high altitude and row orientation in meso- and microclimate and the response of berries to it, we evaluated seven years (2012-2018) of climate data, two years of basic grape (Cabernet Sauvignon, Vitis vinifera L.) quality, and one-year microclimate from veraison to harvest. By comparing two locations (Sidon 2 047 m, Sinon 2 208 m) in Yunnan Province, China, we found that the average temperature has been stable at approximately 15 °C for seven years, with no extreme weather or, noticeable global warming. The Light intensity (LI) in the north-south (NS) was more balanced than the east-west (EW) direction, and the east-west to the south (EW-S) canopy side was almost higher than the other sides. High LI was associated with high photosynthetically active radiation (PAR), ultraviolet (UV), and infrared (IR) light and vice versa. The north-south to the east (NS-E) and east-west to the north (EW-N) sides were characterized by lower LI and higher UV and IR light, and higher total anthocyanin content. Most anthocyanin synthesis-related genes, for example, VvF3'H and VvF3'5'H, were highly expressed in NS-E from veraison to maturity. Perhaps UV and IR light induced their expression. This study provides new insights on the role of differently orientated rows in controlling grape quality due to varied light quality. The findings are globally significant, particularly in the context of climate change, and offer fresh insights into berry physiological responses and decision-making for the management of existing vineyards.