Lipoxygenase ZmLOX3 Enhances Salt Tolerance of Maize Under the Regulation of ZmNAC032

Abstract

Lipoxygenase (LOX) plays a critical role in plant biotic and abiotic stress responses by mediating lipid peroxidation and the production of jasmonic acid (JA). In this study, maize ZmLOX3 was identified as a positive regulator in salt stress tolerance. Overexpression of ZmLOX3 enhanced the salt tolerance of Arabidopsis. When maize seedlings were subjected to salt stress, the ZmLOX3^OE lines exhibited a better growth phenotype than the control (B104) and the zmlox3^CR (CRISPR/Cas) knockout mutants. Overexpression of ZmLOX3 improved ROS scavenging, Na⁺/K⁺ homeostasis, and cell membrane stability. Transcriptome analyses revealed that ZmLOX3^OE triggered the expression of genes involved in both the JA synthesis and signaling pathways. A transcription factor ZmNAC032 was identified via Y1H screening and was able to bind to the C[A/G]CG[T/G] sequence in the ZmLOX3 promoter and activate its expression. These findings are helpful for deciphering the function and regulatory status of ZmLOX in improving salt tolerance.