PROTON GRADIENT REGULATION 5 enables efficient C4 photosynthesis under fluctuating light.

ABSTRACT: PROTON GRADIENT REGULATION 5 (PGR5) plays a critical role in generating proton motive force across thylakoid membranes and supporting photoprotection under fluctuating light in C3 plants. It is proposed that this function is achieved by regulating cyclic electron flow around Photosystem I. During the evolutionary transition from C3 to C4 photosynthesis, PGR5 abundance in leaves has increased, coinciding with an enhancement in cyclic electron flow rate. To investigate the role of PGR5 in C4 photosynthesis and photoprotection, we generated Setaria viridis (a model C4 monocot) lines with null pgr5 alleles. We demonstrate that loss of PGR5 severely impairs the establishment of proton motive force, photosynthetic control, and energy-dependent non-photochemical quenching at high irradiances, lea

SUBMITTER: Woodford R 

PROVIDER: S-EPMC12541380 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature