Subtilisin-like protease 4 regulates cold tolerance through cell wall modification in rice

Area of Science:

• Plant Biology
• Molecular Genetics
• Abiotic Stress Response

Background:

• Rice (Oryza sativa) is vulnerable to cold, particularly during seedling development.
• Understanding cold tolerance mechanisms in rice is crucial, yet limited genes are identified.
• Plant subtilisin-like proteases (SUBs/SBTs) are enzymes involved in plant growth and stress responses.

Purpose of the Study:

• To investigate the role of the rice SUB gene family in cold stress response.
• To determine if SUB4 is involved in regulating cold tolerance in rice seedlings.

Main Methods:

• Generated a loss-of-function mutant for the SUB4 gene.
• Assessed cold tolerance of sub4 mutant seedlings through survival rates and physiological measurements.
• Conducted transcriptomic analysis to identify differentially expressed genes in response to cold stress.

Main Results:

• The sub4 mutant showed significantly enhanced cold tolerance at the seedling stage.
• Physiological improvements in the mutant included reduced electrolyte conductivity and malondialdehyde, and increased antioxidant enzyme activity.
• Transcriptomic data indicated SUB4 affects cold-responsive genes related to metabolism, signal transduction, and notably, cell wall functions.

Conclusions:

• SUB4 negatively regulates cold response in rice seedlings.
• The mechanism may involve SUB4's influence on cell wall organization and related processes.
• This study identifies SUB4 as a potential target for improving rice cold hardiness.