Maize Aldehyde Decarbonylase 1 Gene (ZmCER1) Positively Regulates Salt and Drought Tolerance by Improving Wax Synthesis and Reactive Oxygen Species Detoxification.

Maize (Zea mays L.) is a vital global crop whose productivity is severely threatened by abiotic stresses. Epicuticular waxes provide a hydrophobic barrier that protects land plants from environmental stresses. However, the role of key wax biosynthetic enzymes, such as aldehyde decarbonylase CER1, in maize stress adaptation remains unclear. In this study, we performed a functional characterization of ZmCER1 in maize. Our results show that the overexpression of ZmCER1 in both Arabidopsis and maize substantially improved tolerance to these abiotic stresses. Under stress conditions, the transgenic plants displayed better growth performance, elevated activities of antioxidant enzymes, and reduced levels of oxidative damage markers. Additionally, the alkane content-especially that of C29 and C31-was significantly increased in the ZmCER1OE lines. Through a yeast two-hybrid screening (Y2H screening), we identified the peroxisomal membrane protein ZmPEX14 as an interacting partner of ZmCER1, and the interaction was further confirmed by luciferase complementation (LUC) and bimolecular fluorescence complementation (BiFC) assays. We propose a model wherein ZmCER1 enhances stress tolerance not only by reinforcing the cuticular wax barrier but also by potentially regulating reactive oxygen species (ROS) detoxification via association with ZmPEX14. Collectively, our findings establish ZmCER1 as a key regulator of abiotic stress tolerance in maize and a promising candidate for the molecular breeding of stress-resilient crops.