PpZAT10 negatively regulates peach cold resistance predominantly mediated by inhibiting VIN activity

Sucrose is an important contributor to resist chilling stress during peach storage at low temperatures, but the underlying regulatory mechanism of sugar metabolism is still elusive. In this study, using peach fruit, we investigated how the zinc finger protein, PpZAT10 regulates vacuolar invertase (VIN), a regulator of sucrose metabolism. The expression of PpZAT10 is positively responsive to low temperature. When transient overexpressed PpZAT10 in peach fruit, the expression of PpVIN2 expression was not significantly affected, but VIN activity was enhanced. Yeast one-hybrid, electrophoretic mobility shift assays, and dual-luciferase assays demonstrated that PpZAT10 can bind the PpVIN2 promoter and thereby suppress its transcription. Yeast two-hybrid, bimolecular fluorescence complementation (BiFC), and recombinant protein analysis showed that PpZAT10 directly interacts with PpVIN2, and via this interaction, enhances the activity of PpVIN2. Our results demonstrate that PpZAT10 regulates VIN2 at the transcriptional level and the protein level, but protein-protein interaction may be the more important way to regulate VIN activity and indirectly of sucrose metabolism in peach fruit.