Photoreceptor-induced LHL4 protects photosystem II in Chlamydomonas reinhardtii

ABSTRACT: Photosynthesis, the fundamental process using light energy to convert CO2 to organic matter, is vital for life on Earth. It relies on capturing light through light-harvesting complexes in photosystems I and II and converting light energy into chemical energy. Composition and organization of photosystem core complexes are well conserved across evolution, and are highly susceptible to photodamage. Consequently, a large diversity of photoprotective mechanisms have evolved in photoautotrophs, finely tuned for the specific light conditions. Light Harvesting Complex protein family (LHC and LHC-like families) have acquired a dual function during evolution. Members of the LHC antenna complexes of photosystems capture light energy whereas others dissipate excess energy that cannot be harnessed for photosynthesis. This process mainly occurs through non photochemical quenching (NPQ). In this work, we focus on the LHL4 protein, which is induced by UV-B and blue light photoreceptor signaling pathways in the model green microalgae Chlamydomonas reinhardtii. Our work demonstrates that alongside established NPQ effectors, LHL4 plays a key role in photoprotection, preventing singlet oxygen accumulation in photosystem II and thereby promoting cell survival upon light stress. LHL4 protective function is distinct from that of NPQ-related proteins, since it directly binds to the transient monomeric form of the core photosystem II complex, safeguarding its integrity. Our LHL4 characterization expands our understanding of the interplay between light harvesting and photoprotection mechanisms upon light stress in photosynthetic microalgae.

INSTRUMENT(S): Orbitrap Exploris 480

ORGANISM(S): Chlamydomonas Reinhardtii

TISSUE(S): Photosynthetic Cell

SUBMITTER: Pascal Albanese  

LAB HEAD: Pascal Albanese

PROVIDER: PXD049352 | Pride | 2025-01-28

REPOSITORIES: Pride