Researchers have identified a new control process in photosynthesis within the green alga Chlamydomonas reinhardtii that aids adaptation to varying light levels. The findings, reported in Nature Plants, detail how a protein interaction between the cytochrome b6f complex and the kinase STT7 manages the photosynthetic system. This process supports state transitions that balance the two photosystems to maintain efficient energy production under changing sunlight. The kinase STT7 phosphorylates a subunit of the cytochrome b6f complex known as PetD at threonine 4, creating a feedback loop that deactivates the kinase and prevents excess activity. The study combined genetic approaches, performance measurements, and biochemical tests to confirm the role of the N-terminal region of PetD. Teams from the University of Münster, Stanford University, and Sorbonne Université contributed to the work.
