Redox‐mediated structural and functional switching of C‐repeat binding factors enhances plant cold tolerance
Seong Dong Wi, Eun Seon Lee, Joung Hun Park, Ho Byoung Chae, Seol Ki Paeng, Su Bin Bae, Thi Kieu Anh Phan, Woe‐Yeon Kim, Dae‐Jin Yun, Sang Yeol Lee
Abstract
C-repeat binding factors (CBFs) are key cold-responsive transcription factors that play pleiotropic roles in the cold acclimation, growth, and development of plants. Cold-sensitive cbf knockout mutants and cold-tolerant CBF overexpression lines exhibit abnormal phenotypes at warm temperatures, suggesting that CBF activity is precisely regulated, and a critical threshold level must be maintained for proper plant growth under normal conditions. Cold-inducible CBFs also exist in warm-climate plants but as inactive disulfide-bonded oligomers. However, upon translocation to the nucleus under a cold snap, the h2-isotype of cytosolic thioredoxin (Trx-h2), reduces the oxidized (inactive) CBF oligomers and the newly synthesized CBF monomers, thus producing reduced (active) CBF monomers. Thus, the redox-dependent structural switching and functional activation of CBFs protect plants under cold stress.