The Plastid Lipocalin LCNP Is Required for Sustained Photoprotective Energy Dissipation in Arabidopsis

Alizée Malnoë (1, 2) , Alex Schultink (2) , Sanya Shahrasbi (2) , Dominique Rumeau (3) , Michel Havaux (4) , Krishna K Niyogi (5, 2)

1 PMMC - Physiologie membranaire et moléculaire du chloroplaste
2 LBNL - Lawrence Berkeley National Laboratory [Berkeley]
3 PPV - Protéines de Protection des Végétaux
4 PEPSS - Plant Environmental Physiology and Stress Signaling
5 Department of Plant and Microbial Biology [Berkeley]

Light utilization is finely tuned in photosynthetic organisms to prevent cellular damage. The dissipation of excess absorbed light energy, a process termed nonphotochemical quenching (NPQ), plays an important role in photoprotection. Little is known about the sustained or slowly reversible form(s) of NPQ and whether they are photoprotective, in part due to the lack of mutants. The Arabidopsis thaliana suppressor of quenching1 (soq1) mutant exhibits enhanced sustained NPQ, which we term qH. To identify molecular players involved in qH, we screened for suppressors of soq1 and isolated mutants affecting either chlorophyllide a oxygenase or the chloroplastic lipocalin, now renamed plastid lipocalin (LCNP). Analysis of the mutants confirmed that qH is localized to the peripheral antenna (LHCII) of photosystem II and demonstrated that LCNP is required for qH, either directly (by forming NPQ sites) or indirectly (by modifying the LHCII membrane environment). qH operates under stress conditions such as cold and high light and is photoprotective, as it reduces lipid peroxidation levels. We propose that, under stress conditions, LCNP protects the thylakoid membrane by enabling sustained NPQ in LHCII, thereby preventing singlet oxygen stress.

Domaines: Botanique

Alizée Malnoë, Alex Schultink, Sanya Shahrasbi, Dominique Rumeau, Michel Havaux, et al.. The Plastid Lipocalin LCNP Is Required for Sustained Photoprotective Energy Dissipation in Arabidopsis. The Plant cell, 2018, 30 (1), pp.196-208. ⟨10.1105/tpc.17.00536⟩. ⟨hal-01856102⟩