StSN2 interacts with the brassinosteroid signaling suppressor StBIN2 to maintain tuber dormancy.

After harvest, potato tubers undergo an important period of dormancy, which significantly impacts potato quality and seed vigor. has been reported as a key gene for maintaining tuber dormancy; in this study, we explored the molecular mechanism by which maintains dormancy. StBIN2 was first identified as a candidate protein that interacts with StSN2 by co-immunoprecipitation/mass spectrometry, and both qPCR and enzyme activity experiments showed that can promote the StBIN2 expression and activity. In addition, the interaction between StSN2 and StBIN2 was verified by yeast two-hybrid, luciferase complementation experiments and co-immunoprecipitation. Bioinformatics analysis and site-directed mutagenesis confirmed the critical role of cysteine residues of StBIN2 in its binding to StSN2. Similar to that of , overexpression of extended the dormancy of potato tuber. Interaction between StSN2 and StBIN2 increased the activity of the StBIN2 enzyme, inhibited the expression of , and suppressed BR signaling. On the contrary, this interaction promoted the expression of // and , key genes of ABA signaling, and the phosphorylation of , thereby promoting ABA signaling. Altogether, our results indicate that StSN2 interacts with StBIN2 through key cysteine residues and StBIN2 maintains tuber dormancy by affecting ABA and BR signaling. Findings of this research offer new insights into the molecular mechanism by which StSN2 maintains potato tuber dormancy through interaction with StSIN2 and provide guidance for potato improvement.