Salt tolerance evaluation and transcriptome analysis of maize mutant caspl2b2

Salt stress-sensitive mutants are crucial genetic materials for studying the genetic basis and molecular mechanisms of salt tolerance in crops. In this study, the maize inbred line LY8405 and the mutant caspl2b2 were used to investigate phenotype, physiological, and biochemical indices at the seedling stage under normal growth and salt stress conditions. The results showed that, compared to LY8405, the survival rate of caspl2b2 significantly decreased under salt stress, and the growth of aboveground parts was notably inhibited. The content of Na+ ions and malondialdehyde (MDA) in aboveground parts significantly increased, while transpiration rate, stomatal conductance, and intercellular CO2 concentration also increased significantly. Conversely, the net photosynthetic rate significantly decreased. To uncover the molecular basis of the phenotypic differences under salt stress, transcriptome analysis was performed on leaf tissues of LY8405 and caspl2b2 under normal growth and salt stress conditions. The results revealed that differentially expressed genes (DEGs) were mainly concentrated in glutathione transferase activity, glutathione metabolism, REDOX enzyme activity, and cell homeostasis, with glutathione metabolism being the most significant. This study not only provides important germplasm resources for the genetic basis analysis of crop salt tolerance, but also lays a foundation for the identification of salt tolerance genes and the analysis of genetic regulatory networks.