Regulatory effect of exogenous melatonin on the expression of enzyme genes in the AsA-GSH cycle and nitrogen metabolism in rice seedlings under NaCl stress

In this study, the regulatory effect of exogenous melatonin on the expression of genes related to the AsA-GSH cycle and nitrogen metabolism in seedlings under NaCl stress was determined; the homology between enzyme genes and similar genes in other species was analyzed by applying different concentrations of exogenous melatonin to rice seedlings under NaCl stress; and the morphology and physiological indicators of seedlings were determined. Exogenous melatonin was found to upregulate the expression of OsGR3 , OsGPX1 , OsNR2 , OsGS1 , and OsGOGAT1 in seedlings under NaCl stress, which enhanced the enzyme activities of the AsA-GSH cycle and nitrogen metabolism, ultimately reducing the content of reactive oxygen species (ROS) and improving the photosynthetic rate and nitrogen efficiency. A high homology was found when rice OsGR3 , OsGPX1 , OsNR2 , OsGS1, and OsGOGAT1 were compared with similar genes in Arabidopsis thaliana , Hordeum vulgare , Zea mays , and Sorghum bicolor . Further, the location of the gene on the chromosome, the similar gene structure, GO annotation, and KEGG metabolic pathways were explained by the functions and metabolic processes of OsGR3 , OsGPX1 , OsNR2 , OsGS1 , and OsGOGAT1 . Overall, our findings indicate that exogenous melatonin participates in the regulation of enzyme gene expression during the AsA-GSH cycle and nitrogen metabolism, ultimately affecting the activities of related enzymes and alleviating the oxidative damage induced by ROS in seedlings.