1. Lipid and carotenoid cooperation-driven adaptation to light and temperature stress in Synechocystis sp. PCC6803
- Author
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Mihály Kis, Zoltán Gombos, Jana Knoppová, Josef Komenda, László Kovács, Ildikó Domonkos, Sindhujaa Vajravel, Tomas Zakar, Eva Herman, and Hajnalka Laczkó-Dobos
- Subjects
0106 biological sciences ,0301 basic medicine ,Cyanobacteria ,Time Factors ,Photoinhibition ,Genotype ,Light ,Mutant ,Biophysics ,Xanthophylls ,Photosystem I ,Photosynthesis ,Thylakoids ,01 natural sciences ,Biochemistry ,Article ,Membrane Lipids ,03 medical and health sciences ,Stress, Physiological ,Carotenoid ,chemistry.chemical_classification ,Photosystem I Protein Complex ,biology ,Cell Membrane ,Synechocystis ,Temperature ,Cell Biology ,Lipid Metabolism ,beta Carotene ,biology.organism_classification ,Adaptation, Physiological ,Phenotype ,030104 developmental biology ,chemistry ,Xanthophyll ,Mutation ,010606 plant biology & botany - Abstract
Polyunsaturated lipids are important components of photosynthetic membranes. Xanthophylls are the main photoprotective agents, can assist in protection against light stress, and are crucial in the recovery from photoinhibition. We generated the xanthophyll- and polyunsaturated lipid-deficient ROAD mutant of Synechocystis sp. PCC6803 (Synechocystis) in order to study the little-known cooperative effects of lipids and carotenoids (Cars). Electron microscopic investigations confirmed that in the absence of xanthophylls the S-layer of the cellular envelope is missing. In wild-type (WT) cells, as well as the xanthophyll-less (RO), polyunsaturated lipid-less (AD), and the newly constructed ROAD mutants the lipid and Car compositions were determined by MS and HPLC, respectively. We found that, relative to the WT, the lipid composition of the mutants was remodeled and the Car content changed accordingly. In the mutants the ratio of non-bilayer-forming (NBL) to bilayer-forming (BL) lipids were found considerably lower. Xanthophyll to β-carotene ratio increased in the AD mutant. In vitro and in vivo methods demonstrated that saturated, monounsaturated lipids and xanthophylls may stabilize the trimerization of Photosystem I (PSI). Fluorescence induction and oxygen-evolving activity measurements revealed increased light sensitivity of RO cells compared to those of the WT. ROAD showed a robust increase in light susceptibility and reduced recovery capability, especially at moderate low (ML) and moderate high (MH) temperatures, indicating a cooperative effect of xanthophylls and polyunsaturated lipids. We suggest that both lipid unsaturation and xanthophylls are required for providing the proper structure and functioning of the membrane environment that protects against light and temperature stress.
- Published
- 2017