•Proteomic analysis was conducted on root tissues from a T-DNA insert mutant of osmybcc-1(also known as OsMYBc) and its wildtype after being exposed to salt stress for 12 h. Results showed that the wildtype accumulated and excluded more K+in the leaf tips, and proteomics results revealed 8523 proteins of which 7598 were quantifiable.•DEPs enriched in DNA repair and recombinase pathways were found in mutants compared to wildtypes without salt treatment. Reactive nitrogen species response was enriched in mutants with salt treatment.•The ion and anion transmembrane transporters were down regulated and enriched in both the mutant and wildtype in response to salt stress and 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 were more tolerant to salt stress than its gene knockout mutant nrt2.1.