Transcriptional variation analysis of Arabidopsis ecotypes in response to drought and salt stresses dissects commonly regulated networks

Salinity and drought conditions commonly result in osmotic and oxidative stresses, while salinity additionally causes ionic stress. In this study, we identified specific genes regulated by osmotic and ionic stresses in five Arabidopsis ecotypes. Shahdara (SHA) and C24 ecotypes were more tolerant to salt and drought stresses at the seedling growth stage, as evidenced by lower water loss rate, lower electrolyte leakage, and higher survival rate when compared to the other three ecotypes under drought and salinity conditions. Transcriptomic analysis revealed that 3700 and 2242 genes were differentially regulated by salt and osmotic stresses, respectively. Totally 78.1% of upregulated and 62.0% of downregulated genes by osmotic stress were also commonly regulated by salt stress. Gene ontology term enrichment analysis showed that auxin indole-3-acetic acid (IAA), abscisic acid, cytokinin, and gibberellic acid pathways were regulated by the osmotic stress, while IAA, jasmonic acid, and ethylene pathways were changed by the ionic stress. The nutrient and water uptake pathways were regulated by both the osmotic and ionic stresses, whereas ion transportation and kinase pathways were modulated by the ionic stress. Additionally, we characterized bHLH61 as a negative regulator in response to salt and drought stresses. This study provided new clues of plant responses to salt and drought stresses.

Automated summary

Salinity and drought conditions lead to osmotic and oxidative stresses, with salinity also causing ionic stress. Through transcriptomic analysis, specific genes regulated by these stresses in five Arabidopsis ecotypes were identified, with SHA and C24 ecotypes showing greater tolerance. The study revealed common regulation of genes by osmotic and ionic stresses, and highlighted pathways affected by these stresses, providing new insights into plant responses to salt and drought stresses.