Loss of PSAE redirects PGRL1 to photosystem I and enhances PGR5-dependent cyclic electron transfer in Arabidopsis
Degen, G. E.; Park, E.; Johnson, M.
Plant Signaling
Every tomato plant you've ever saved from afternoon sun stress is running the same protective circuit this study just cracked open — and understanding it could lead to crops that handle brutal summer heat without wilting or losing yield.
Inside every green leaf, sunlight powers two different energy pathways. This study found that when one tiny protein piece is missing from a plant's light-capturing machinery, the plant automatically reroutes more energy through a backup loop that acts like a pressure-relief valve, preventing damage during intense light. The key player in this rerouting is a protein called PGRL1, which physically moved closer to the light-harvesting complex when the first protein was absent — like a traffic cop switching lanes.
Key Findings
Loss of the PSAE subunit in Arabidopsis strongly enhances cyclic electron transfer primarily through the PGR5-dependent pathway, not the NDH pathway.
PGRL1 protein redistributes from a mixed membrane location to become predominantly associated with photosystem I in psae1-3 mutants, providing a structural explanation for the enhanced cyclic flow.
Plants lacking both PSAE and NDH (psae1-3 ndho double mutants) maintained elevated proton flux but showed significantly reduced CO2 fixation and growth, revealing that NDH still makes a meaningful physiological contribution when the PSI acceptor side is disrupted.
chevron_right Technical Summary
Scientists discovered that removing a specific protein from photosystem I in Arabidopsis plants shifts the cell's energy routing—boosting a secondary power loop that helps protect the plant from light damage and maintain efficient carbon capture.
Abstract Preview
Electrons energised by light energy at photosystem I (PSI) primarily enter the linear photosynthetic electron transfer (LET) or cyclic electron transfer (CET) pathway. The balance between LET and C...
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