The ascorbate-glutathione cycle coming of age

Area of Science:

• Plant Physiology
• Biochemistry
• Cellular Signaling

Background:

• The ascorbate-glutathione cycle and water/water cycle are established systems for managing reactive oxygen species (ROS) generated during plant metabolism.
• Emerging research reveals expanded roles for these cycles and their enzymes beyond ROS detoxification.

Purpose of the Study:

• To review current knowledge on the ascorbate-glutathione cycle and water/water cycle in plants.
• To highlight the involvement of these cycles in plant growth, development, and defense signaling pathways.
• To discuss the 'moonlighting' functions and post-translational modifications of the enzymes within these cycles.

Main Methods:

• Literature review and synthesis of recent research findings.
• Analysis of the role of ascorbate-glutathione and water/water cycles in plant signaling.
• Examination of enzyme post-translational modifications and protein interactions.

Main Results:

• Ascorbate-glutathione and water/water cycles are integral to ROS homeostasis.
• Enzymes in these cycles participate in intrinsic plant signaling pathways regulating growth, development, and defense.
• Enzymes exhibit 'moonlighting' functions, are post-translationally modified, and interact extensively with other signaling proteins.

Conclusions:

• The ascorbate-glutathione cycle is central to cellular redox systems, integrating plant signaling.
• These cycles are critical for energy-sensitive communication across cellular compartments.
• Understanding these cycles provides insight into plant adaptation and stress responses.