For an overall evaluation of the protein redox status in grxs12 leaves, the iodoTMT-based redox proteomics approach was employed. After protein extraction, the free thiols in Cys were NEM-blocked, and then the Cys thiols with reversible oxidations such as sulfenic acids (-SOH), S-glutathionylation (-SSG), and disulfide bonds were reduced by DTT. Finally, the newly generated thiols in Cys were specifically labeled with iodoTMT-tags. The redox proteomics identified 227 peptides (162 proteins) exhibited changes in the redox status in grxs12 mutants compared to WT, including 88 more oxidized peptides and 139 less oxidized peptides.