ERF transcription factor PpRAP2.12 activates PpVIN2 expression in peach fruit and reduces tolerance to cold stress

The vacuolar invertase gene PpVIN2 negatively regulates cold resistance in peach fruit by promoting sucrose degradation. However, the regulatory mechanisms that control PpVIN2 transcription are not yet understood. In this study, we identified an ethylene-responsive transcription factor (ERF) in a yeast one-hybrid library screen using the PpVIN2 promoter (PpVIN2pro) as bait. ERF PpRAP2.12 directly binds to the ACCGAC cis-element in the PpVIN2pro region, resulting in enhanced promoter activity. In peach fruit, transient overexpression of PpRAP2.12 increases PpVIN2 expression and vacuolar invertase (VIN) activity and decreases sucrose levels. Ectopic expression of PpRAP2.12 in tobacco reduces tolerance to cold stress, resulting in a lower survival rate, higher NtVIN expression and VIN enzymatic activity, and elevated production of reactive oxygen species. Together, these findings suggest that PpRAP2.12 binds to PpVIN2pro and positively regulates its activity to promote sucrose degradation. PpRAP2.12 thus functions as a negative regulator of plant defenses against chilling stress, and may provide a target for mitigating chilling injury in peach fruit.