Salt induced protein dynamics in young rice roots of osmybcc-1 mutant and its involvement in salt stress

Plants experiencing salt stress often exhibit an ionic homeostasis disorder as a primary symptom. Transcription factor OsMYBc positively regulates OsHKT1;1 to control Na+ accumulation in rice shoots. In this study, root tissues from a T -DNA insert mutant of osmybcc-1 (also known as OsMYBc) and its wild type were analyzed using proteomic methods after being exposed to salt stress for 12 h. Physiological results showed that the wildtype accumulated and excluded more K+ in the leaf tips. Proteomics results revealed 8523 proteins were identified and 7598 were quantifiable. Differentially expressed proteins (DEPs) that were enriched in DNA repair and recombinase pathways were found when comparing mutants with wild types without salt treatment. However, DEPs involved in response to reactive nitrogen species were enriched in the mutant after salt treatment. Moreover, DEPs in response to reactive nitrogen species such as high-affinity nitrate transporter family member (NRT) were enriched when comparing mutants with wild types and with salt treatment as well. Additionally, the ion and anion transmembrane transporters were downregulated and enriched in both the mutant and wildtype in response to salt stress. The RNA abundance changes observed in genes related to reactive nitrogen species response and ion and anion transmembrane transport were consistent with the proteomic results. The NRT2.1- overexpressing rice was more tolerant to salt stress than its gene knockout mutant nrt2.1. These findings highlighted protein dynamics in roots in response to salt stress, as well as the providing of some potential targets for MYB transcription factor in salt stress mitigation.