Multi-omics analysis reveals molecular mechanisms of maize responses to hexavalent chromium toxicity

Hexavalent chromium [Cr(VI)] is a highly toxic heavy metal that adversely affects plant growth and food safety. Here, we investigated the molecular responses of maize seedlings (hybrid Zhengdan958(ZD958) and parental lines Chang7-2(C72) and Zheng58(Z58)) to 20 mg/L Cr(VI) stress using transcriptomic and proteomic analyses. Cr(VI) treatment induced 1226 commonly upregulated and 655 downregulated genes across all three genotypes, with upregulated genes enriched in stress- and defense-related processes (oxidative stress, xenobiotic response, hormone signaling) and downregulated genes associated with growth and development (cell wall biosynthesis, organ morphogenesis). Proteomic analysis showed similar patterns, highlighting key modules mediating Cr(VI) tolerance. Antioxidant genes (catalase3, glutaredoxin14, acco2, acco5) were significantly upregulated, indicating activation of ROS-scavenging pathways. These results reveal coordinated transcriptional and proteomic responses that protect maize against Cr(VI)-induced oxidative stress while suppressing growth, providing candidate genes and pathways for breeding maize with enhanced tolerance to heavy metal-contaminated soils.