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Regulation of respiration when the oxygen availability changes
Kapuganti J Gupta1, Ana Zabalza, Joost T van Dongen
1Max Planck Institute of Molecular Plant Physiology, Energy Metabolism Research Group, Am Muehlenberg 1, D-14476 Potsdam, Germany.
Physiologia Plantarum
|June 25, 2009
Summary
Plants must adapt their energy metabolism to fluctuating oxygen levels. This study explores how alternative oxidase (AOX) helps maintain oxygen homeostasis and reduce reactive oxygen species (ROS) production in plant mitochondria.
Area of Science:
- Plant Physiology
- Mitochondrial Respiration
- Biochemistry
Background:
- Oxygen is crucial for plant energy metabolism, but plants lack efficient internal oxygen delivery systems.
- Plant cells must constantly adapt to varying oxygen tensions within tissues.
- Internal oxygen levels are influenced by tissue diffusion resistance and respiratory activity.
Purpose of the Study:
- To review and discuss the regulation of plant respiration in response to oxygen availability.
- To compare plant respiration regulation with that in animal mitochondria.
- To propose a hypothesis for an additional role of alternative oxidase (AOX) in oxygen homeostasis.
Main Methods:
- Literature review and commentary on existing research on plant respiration.
- Inclusion of data and theories on animal mitochondrial respiration regulation.
- Analysis of the roles of cytochrome-c oxidase (COX) and AOX in adaptive respiration.
Main Results:
- Discusses the adaptive responses of respiration involving glycolytic flux, COX, and AOX.
- Reviews conflicting viewpoints in the scientific literature regarding plant respiration.
- Proposes that AOX may play a role in maintaining mitochondrial oxygen homeostasis.
Conclusions:
- AOX may have a role in oxygen homeostasis within plant mitochondria.
- AOX's lower oxygen affinity compared to COX prevents interference with COX activity.
- AOX activity can lower free oxygen concentrations, reducing reactive oxygen species (ROS) production.
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