Transcriptome analysis of Upland Cotton revealed novel pathways to scavenge reactive oxygen species (ROS) responding to Na2SO4 tolerance

To explore the mechanisms of cotton response to Na2SO4 stress, we used next-generation sequencing (NGS) technology to study transcriptional changes of cotton under the treatment of 300 mmol• L-1 Na2SO4 solution at 12 h and the control with water at 12 h. A total of 15,524, 20,409 and 12,146 differentially expressed genes (DEGs) were identified in cotton roots, stems and leaves between treatment and control, respectively. Gene ontology (GO) analysis indicated the enrichment of DEGs involved in various stimuli or stress responses. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that DEGs associated with plant hormone signal transduction, plant-pathogen interaction, and Starch and sucrose metabolites were regulated in response to the Na2SO4 stress. We further analyzed genes enriched in ROS (reactive oxygen species) scavenging system including osmotic stress and ion toxicity were significantly up-regulated. In addition, analysis for sulfur metabolism, results in to identification of two rate limiting enzymes APR and OASTL during synthesis of GSH from SO42-. The analysis of the expression profiles of diverse tissues under Na2SO4 stress and identification of relevant key hub genes in a network crosstalk will provide a strong foundation and valuable clues for genetic improvements of cotton in response to various salt stresses. Overall design: The transcriptional levels of cotton was tested in cotton roots, stems and leaves between the treatment of 300 mmol• L-1 Na2SO4 solution at 12 h and the control with water at 12 h.