OsbZIP83-OsCOMT15 module confers melatonin-ameliorated cold tolerance in rice.

Area of Science:

• Plant Biology
• Molecular Biology
• Biochemistry

Background:

• Cold stress is a major abiotic challenge for crops.
• Melatonin (Mel) is known to improve plant cold tolerance, but its precise regulatory mechanisms are unclear.

Purpose of the Study:

• To elucidate the molecular mechanism of Mel-mediated cold tolerance in rice.
• To identify key genes and transcription factors involved in this process.

Main Methods:

• Gene knockout and overexpression in rice.
• Analysis of gene expression under cold stress.
• Measurement of melatonin content.
• Identification of transcription factor binding sites.

Main Results:

• OsCOMT15 was identified as a cold-responsive gene crucial for Mel biosynthesis and rice cold tolerance.
• OsbZIP83, a bZIP transcription factor, directly regulates OsCOMT15 expression.
• OsbZIP83 also activates known cold-responsive genes (OsDREB1A and OsDREB1G).
• Loss-of-function mutants showed cold hypersensitivity and reduced Mel levels, while overexpression lines showed enhanced tolerance.

Conclusions:

• The OsbZIP83-OsDREB1s/OsCOMT15 regulatory module is essential for rice cold tolerance.
• This module orchestrates Mel synthesis and cold response pathways.
• Findings offer insights into plant hormone responses to cold and strategies for crop improvement.