Genotype-Specific Features of Cold-Induced Sweetening Process Regulation in Potato Varieties Nikulinsky, Symfonia, and Nevsky

—In this study, we performed expression analysis of genes associated with cold-induced sweetening in potato tubers: vacuolar invertase ( Pain-1 ), sucrose synthase ( SUS4 ), and invertase inhibitor ( InvInh2 ). Potato varieties Nikulinsky, Symfonia, and Nevsky were used. All three varieties were found to accumulate sugars at low temperatures; the maximum accumulation of reducing sugars was observed at 4°C. It was found that the expression pattern of genes associated with cold-induced sweetening differs depending on the variety and storage duration. The increased expression of vacuolar invertase and its inhibitor is more pronounced at the beginning of storage period, whereas the increased expression of sucrose synthase is more pronounced after 3 months of storage. At early storage periods, high expression of invertase and low expression of inhibitor is observed in the Dutch variety Symfonia, and vice versa in the Russian varieties Nikulinsky and Nevsky. The involvement of the studied genes in the process of cold-induced sweetening is discussed.