PpCaM7 and PpCAMTA5 Synergistically Mitigate Chilling-Induced Browning by Suppressing Reactive Oxygen Species Synthesis in Peach Fruit

This study investigated the potential regulatory mechanisms influencing chilling injury in peach fruit under various storage temperatures (0 ℃ and 5 ℃) and calcium treatments (calcium chloride (CaCl2) and trifluoperazine (TFP)). The results showed that 0 ℃ storage and CaCl2 treatment activated the expression of PpCAMTA5, while repressed the expression of PpNAC25, PpPAO, PpRBOHA, PpRBOHC, and PpRBOHD, and reduced hydrogen peroxide (H2O2) content. This concerted regulation effectively suppressed chilling-induced browning in peach fruit during cold storage. However, the opposite effects were presented in TFP-treated fruit. Additionally, the interaction between PpCaM7 and PpCAMTA5 inhibited PpNAC25-mediated transcriptional activation of PpPAO, PpRBOHA, PpRBOHC, and PpRBOHD. Thus, these results suggested that the PpCaM7-PpCAMTA5 complex mitigates chilling injury in peach fruit via inhibiting reactive oxygen species (ROS) production.