Identification of potential metabolites responsible for cold tolerance in buds of Vitis amurensis

Cold tolerance is one of the important traits for grapevine, especially in regions with extremely low temperatures in winter. Vitis amurensis is wild species in the Vitis genus with excellent cold hardiness compared with Vitis vinifera. However, metabolites that contribute to the cold tolerance of V. amurensis remain unknown. Here, the metabolomics of buds from V. amurensis 'Zuoshan-1' during cold acclimation (CA) were identified, and cold-sensitive cultivar (V. vinifera 'Jingzaojing') was used as the control. The buds were collected in October, November, and December in 2016 and 2018. The cold hardiness of the buds increased during CA in the two grapevines. However, browning was observed only in V. vinifera buds at temperature below −10 °C. Among detected metabolites from buds, 443 metabolites were overlapped between two years. Forty-four and thirty differentially accumulated metabolites (DAMs) were identified in V. amurensis and V. vinifera, respectively. Ten DAMs including monoacylglycerol (MAG, 18 : 2) isomer1, trehalose 6-phosphate, and D-glucose showed identical variations in the two grapevines, indicating conserved CA responses within the Vitis genus. Eighteen DAMs exhibited higher accumulation in V. amurensis than in V. vinifera. Maltotetraose, D-glucoronic acid, L-aspartic acid, azelaic acid, and 4-hydroxybenzoic acid were reported to accumulate during CA in other plants. Enhanced cold tolerance was detected in grapevine leaves with exogenous 5 mmol · L-1 L-aspartic acid and 1% proanthocyanidins. Potential contributions of other DAMs found in V. amurensis such as Cyanidin 3-O-glucoside need to be further elucidated. Thus, eighteen metabolites accumulated in V. amurensis can be used for practical application in improvement of cold resistance in grapevine. Our findings provide new insights into understanding the cold hardiness of V. amurensis.