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ROS production and signalling in chloroplasts: cornerstones and evolving concepts
Christine H Foyer1, Guy Hanke2
1School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, B15 2TT, UK.
The Plant Journal : for Cell and Molecular Biology
|June 6, 2022
Summary
Reactive oxygen species (ROS) produced during photosynthesis act as signals. Chloroplasts sense environmental changes and transmit these redox signals to the nucleus via ROS.
Area of Science:
- Plant Physiology
- Photosynthesis
- Cellular Signaling
Background:
- Reactive oxygen species (ROS), including singlet oxygen, superoxide (O2●-), and hydrogen peroxide (H2O2), are key indicators of cellular activity.
- Oxygenic photosynthesis generates substantial ROS, reflecting the functional status of the electron transport system and overall metabolism.
- Chloroplasts are recognized as crucial environmental sensors, with photosynthetic ROS production driving retrograde signaling to the nucleus.
Purpose of the Study:
- To investigate the role of reactive oxygen species (ROS) in chloroplast-to-nucleus retrograde signaling.
- To understand how the photosynthetic electron transport chain (PETC) regulates ROS production and signal transduction.
- To elucidate the mechanisms by which chloroplasts sense environmental cues and communicate them to the nucleus.
Main Methods:
- Analysis of ROS production by different complexes within the photosynthetic electron transport chain (PETC).
- Investigation of the regulation of superoxide (O2●-) production in relation to light availability and stromal redox state.
- Identification of sulfhydryl-containing proteins and peptides acting as hydrogen peroxide (H2O2) sensors and signal transducers.
Main Results:
- Photosynthetic electron transport chain (PETC) components regulate superoxide (O2●-) production based on light energy and stromal redox status.
- Chloroplasts contain numerous sulfhydryl-containing proteins capable of sensing hydrogen peroxide (H2O2) and participating in signal transduction.
- ROS signaling pathways are initiated when ROS are produced near or interact with appropriate sensing proteins.
Conclusions:
- Regulated delivery of ROS from the PETC to stromal redox machinery is essential for transmitting environmental redox signals to the nucleus.
- Chloroplast antioxidant systems play a dual role in either propagating ROS signals or scavenging excess ROS.
- Redox changes in stromal carbohydrate metabolism are integral to chloroplast signaling pathways.
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