Physiological and transcriptomic characterization of cold acclimation in endodormant grapevine under different temperature regimes

Changes in temperature during the dormant season, such as the unusual cold or warmth linked to climate change, can affect cold acclimation and endanger the viability of the grape and wine industry. To tackle this problem, we carried out two experiments in a controlled environment to examine the effects of various temperature conditions on the process of cold acclimation in grapevine buds during endodormancy, using transcriptomic monitoring through 3'RNA-seq. Overall design: In Experiment 1, grapevine buds in endodormancy were exposed to controlled temperatures of 22 °C, 11 °C, 7 °C, 4 °C, and 2 °C, and samples were collected at regular intervals of 7, 13, 20, 26, 34, 41, 55, and 69 days after treatment from growth chambers. Experiment 2 was conducted simultaneously with Experiment 1 but divided into two phases: phase I and phase II. In phase I, cuttings taken from the same sample used in Experiment 1 were exposed to constant temperatures of 11°C, 7 °C, and 2 °C in separate growth chambers, starting from 0 days after collection and ending at 26 days after collection. In phase II, which started at day 26 and ended at day 69 after collection, single node cuttings from the 11 °C, 7 °C, and 2 °C treatments were transferred to another growth chamber and subjected to a temperature fluctuation treatment with a mean temperature of 7 °C and a daily variation of ±5 °C (maximum of 12 °C and minimum of 2 °C).