Redox-dependent structural switch and CBF activation confer freezing tolerance in plants

Area of Science:

• Plant Biology
• Molecular Biology
• Biochemistry

Background:

• Cold-responsive C-repeat-binding transcription factors (CBFs) regulate cold tolerance and plant growth.
• Thioredoxin h2 (Trx-h2), a cytosolic redox protein, interacts with CBF1 and is anchored via myristoylation.
• Cold exposure triggers demyristoylation and nuclear translocation of Trx-h2.

Purpose of the Study:

• To elucidate the mechanism of cold-induced activation of CBFs by Trx-h2.
• To investigate the role of Trx-h2 in plant cold tolerance.

Main Methods:

• Investigated protein interactions between Trx-h2 and CBF1.
• Analyzed the subcellular localization of Trx-h2 under cold stress.
• Assessed the impact of Trx-h2 manipulation on cold tolerance in Arabidopsis.

Main Results:

• Demyristoylated Trx-h2 translocates to the nucleus upon cold exposure.
• Nuclear Trx-h2 reduces oxidized CBFs, activating them for gene expression.
• Trx-h2 overexpression lines exhibit significantly enhanced cold tolerance compared to null mutants.

Conclusions:

• Cold-mediated redox changes activate CBFs through Trx-h2-dependent structural switching.
• This mechanism confers plant cold tolerance by regulating cold-responsive gene expression.