A better understanding of the molecular effects of salinity stress is key to improving salt tolerance in Zea mays. In this study, we combined phenotyping with transcript profiling and network analysis to study genotype-specific differences in salt tolerance in Zea mays.
An extensive phenotypic screening identified two genotypes with an extreme phenotypic difference in tolerance towards salt stress. RNA-seq analysis of the selected salt-tolerant (R9) and salt-sensitive (S46) genotype was performed to unveil the molecular mechanism underlying the difference in salt tolerance. GO enrichment and network analysis on the results of the expression analysis identified phosphorylation-dependent signaling processes, ion transportation, oxidation-reduction, glutathione and tryptophan metabolism as the main processes different between the selected tolerant and sensitive genotypes. Genes belonging to the subnetwork enriched for phosphorylation and kinase activity shared a common regulatory element in their promoter region, which matched the binding site of an Arabidopsis TF with known role in salt-stress response.
Network-based transcriptome analysis of two maize genotypes identified pathways associated with differences in genotype-specific salt tolerance and identified a link between transcriptional and posttranslational regulation of salt tolerance.