Elevated Zeaxanthin Bound to Oligomeric LHCII Enhances the Resistance ofArabidopsisto Photooxidative Stress by a Lipid-protective, Antioxidant Mechanism

摘要: The xanthophyll cycle has a major role in protecting plants from photooxidative stress, although the mechanism of its action is unclear. Here, we have investigated Arabidopsis overexpressing gene encoding β-carotene hydroxylase, containing nearly three times amount carotenoids present wild-type. In high light at low temperature wild-type exhibited symptoms severe oxidative stress: lipid peroxidation, chlorophyll bleaching, and photoinhibition. transformed plants, which accumulate over twice as much zeaxanthin wild-type, these were significantly ameliorated. capacity non-photochemical quenching not different compared with therefore an enhancement this process cannot be cause stress tolerant phenotype. Rather, it concluded that results antioxidant effect zeaxanthin. 80–90% violaxanthin was localized to oligomeric LHCII fraction prepared thylakoid membranes. binding pigments intact membranes confirmed by resonance Raman spectroscopy. Based on structural model LHCII, suggest protein/lipid interface active site for activity zeaxanthin, mediates tolerance protection bound lipids.