The invention relates to a method for determining the role of the 
methylation site change of potato StALDH 
gene in low 
temperature stress, which includes the analysis of 
DNA methylation site of StALDHgene under low 
temperature stress, the analysis of expression level of StALDH 
gene under low 
temperature stress and the analysis of NbALDH function in 
plant development and response to low temperature stress. A low temperature stress response mechanism of potato is study from 
epigenetics field, A method for isolate genes invol in response to low temperature stress and changes of their methylationsites was developed, Therefore, cultivating potato varieties with 
cold tolerance and freeze resistance can 
resist the adverse effects of sudden low temperature on potato production, broaden the research on potato tolerance to low temperature stress, and have very important theoretical basis and practical guiding significance for ensuring high yield and stable harvest of potato in China. At the same time, it provides a theoretical reference for the role of 
DNA methylation modification in the response of other plants to stress.