CsZAT10-Mediated Nitric Oxide Signalling Pathway Is Involved in Melatonin-Induced Chilling Tolerance in Cucumber.

Area of Science:

• Plant Science
• Abiotic Stress Physiology
• Molecular Biology

Background:

• Chilling stress significantly impacts cucumber yield.
• Melatonin (MT) is known to modulate plant stress responses.
• The specific molecular interaction between MT and nitric oxide (NO) in cucumber under chilling stress is not well understood.

Purpose of the Study:

• To elucidate the molecular mechanism linking melatonin (MT) and nitric oxide (NO) in cucumber plants subjected to chilling stress.
• To investigate the role of the CsZAT10 transcription factor in mediating MT's effects on chilling tolerance.
• To understand how the CsZAT10-CsGSNOR-NO module contributes to NO homeostasis under chilling conditions.

Main Methods:

• Overexpression and suppression of key genes (CsASMT, CsZAT10) in cucumber plants.
• Measurement of endogenous melatonin, nitric oxide (NO), lipid peroxidation, and reactive oxygen species (ROS).
• Analysis of gene expression (CsGSNOR) and transcription factor binding (CsZAT10 to CsGSNOR promoter).

Main Results:

• Overexpression of melatonin biosynthesis gene CsASMT increased chilling tolerance, decreased NO accumulation, and upregulated CsGSNOR expression.
• CsZAT10 was identified as a transcription factor that directly binds to the CsGSNOR promoter.
• Overexpression of CsZAT10 enhanced chilling resistance by activating CsGSNOR and mediating NO homeostasis, while its suppression reduced tolerance.

Conclusions:

• Melatonin enhances cucumber chilling tolerance through the regulation of the CsZAT10-CsGSNOR-NO module.
• The CsZAT10 transcription factor plays a crucial role in mediating melatonin's protective effects against chilling stress by controlling NO homeostasis.
• This study reveals a novel molecular pathway for melatonin-mediated cold stress adaptation in cucumber.