Multi-omics analysis revealed key metabolic pathway responses in maize seedlings under cadmium stress

Cd contamination poses a serious threat to maize production by inducing oxidative stress and disrupting vital physiological processes. This study systematically investigated the time-dependent dynamic responses of maize seedlings to Cd stress. Physiological assessments revealed that Cd stress triggered excessive accumulation of ROS. MDA levels in roots increased significantly at all time points, whereas shoots exhibited a delayed accumulation pattern. The activities of antioxidant enzymes (SOD, CAT, and POD) displayed distinct tissue- and time-specific responses. Transcriptomic profiling identified 8789 DEGs that exhibited sustained expression changes across stress durations.These DEGs were significantly enriched in pathways related to photosynthesis, secondary metabolism, and antioxidant defense. Metabolomic analyses detected 286, 158, and 371 DAMs at corresponding time points. Key metabolites, such as salicylic alcohol glucoside and coumaroylquinic acid, were strongly associated with oxidative stress regulation. Integrated transcriptome–metabolome analysis demonstrated that plant hormone signaling, together with the TCA cycle, glycerophospholipid metabolism, phenylpropanoid biosynthesis, and glutathione metabolism, coordinately contribute to Cd detoxification. This occurs by forming a multilayered defense network. These findings reveal the time-dependent adaptive strategies of maize under Cd stress and provide valuable insights for the development of Cd-tolerant maize cultivars.