1. Disulfide reductase activity of thioredoxin-h2 imparts cold tolerance in Arabidopsis
- Author
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Eun Seon Lee, Seong Dong Wi, Sang Yeol Lee, Kieu Anh Thi Phan, Seol Ki Paeng, Su Bin Bae, Joung Hun Park, and Ho Byoung Chae
- Subjects
animal structures ,Mutant ,Thioredoxin h ,Biophysics ,Arabidopsis ,Reductase ,Biochemistry ,Serine ,Gene Expression Regulation, Plant ,medicine ,Molecular Biology ,biology ,Chemistry ,Arabidopsis Proteins ,Cold-Shock Response ,Wild type ,Active site ,Cell Biology ,biology.organism_classification ,biology.protein ,Cold sensitivity ,Thioredoxin ,medicine.symptom ,Oxidation-Reduction - Abstract
Many thioredoxin-h (Trx-h) proteins, cytosolic isotypes of Trxs, have been functionally characterized in plants; however, the physiological function of Arabidopsis Trx-h2, which harbors two active site cysteine (Cys) residues and an N-terminal extension peptide containing a fatty acid acylation site, remains unclear. In this study, we investigated the physiological function of Trx-h2 by performing several abiotic stress treatments using trx-h1-3 knockout mutant lines, and found that the reductase function of Trx-h2 is critical for cold resistance in Arabidopsis. Plants overexpressing Trx-h2 in the trx-h2 mutant background (Trx-h2OE/trx-h2) showed strong cold tolerant phenotypes compared with Col-0 (wild type) and trx-h2 mutant plants. By contrast, Trx-h2(C/S)OE/trx-h2 plants expressing a variant Trx-h2 protein, in which both active site Cys residues were substituted by serine (Ser) residues, showed high cold sensitivity, similar to trx-h2 plants. Moreover, cold-responsive (COR) genes were highly up-regulated in Trx-h2OE/trx-h2 plants but not in trx-h2 and Trx-h2(C/S)OE/trx-h2 plants under cold conditions. These results explicitly suggest that the cytosolic Trx-h2 protein relays the external cold stress signal to downstream cold defense signaling cascades through its protein disulfide reductase function.
- Published
- 2021