Response of ‘Merlot’ grape berry quality and metabolome to meteorological factors at both low and high altitudes

To illustrate the adaptability and quality characteristics of ‘Merlot’ grape berries in high altitude production areas, the metabolites contents and metabolomics of ‘Merlot’ grape berries were analyzed in relation to meteorological factors at low (41 m) and high (2 343 m) altitude wine-producing areas. In this investigation, meteorological factors at low/high-altitude of wine-producing areas were monitored by GPRS-based system. The pH and contents of soluble solids, total acid content, reducing sugars, anthocyanin, total phenol, tannin, flavonoid, flavone and proteins of ‘Merlot’ grape berries were determined. Furthermore, GC/TOF-MS technique was used to analyze the difference in metabolome of ‘Merlot’ grape berries between different altitudes. The results showed that average daily sunshine duration, total radiation during grapes growth period, average daily radiation, average daily temperature difference, average daily temperature and effective cumulative temperature during growth period were higher in high-altitude than those in low-altitude regions. The contents of soluble solid, tannin and reducing sugars of ‘Merlot’ grape berries increased, while the contents of total phenols and anthocyanin decreased in high-altitude wine-producing area, compared with those in low-altitude wine-producing area. Metabolic pathway analysis indicated that ‘Merlot’ grape berries in high-altitude wine-producing area accumulated more amino acids, organic acids, alcohols, polyphenols and sugars than those in low-altitude wine-producing area. Metabolic pathway enrichment analysis showed that 8 amino acid metabolome pathways, 4 carbohydrate metabolome pathways, 3 lipid metabolome pathways and 3 nitrogen metabolome pathways of ‘Merlot’ grape berries were regulated in high-altitude region. DCCA (Detrended Canonical Correspondence Analysis) indicated that average daily sunshine duration, total radiation, average daily radiation, average daily temperature difference, average daily temperature and effective cumulative temperature during growth period were the driving factors of ‘Merlot’ berries quality and metabolites. In conclusion, climatic factors were the main driving factors inducing metabolite differences between ‘Merlot’ grapes berries growing in low- and high-altitude regions. Thus, to adjust metabolites profiles and metabolic pathways was a kind of strategies of ‘Merlot’ grapes for adapting to high altitude ecological environments.