title: Lipid and carotenoid cooperation-driven adaptation to light and temperature stress in Synechocystis sp. PCC6803.
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 was 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.
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, H-6701 Szeged, Hungary. Electronic address: zakar.tomas@brc.mta.hu.
authors.forename: Tomas
authors.initials: T
authors.lastname: Zakar
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, H-6701 Szeged, Hungary. Electronic address: hermaneva91@yahoo.com.
authors.forename: Eva
authors.initials: E
authors.lastname: Herman
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, H-6701 Szeged, Hungary. Electronic address: vajravel.sindhujaa@brc.mta.hu.
authors.forename: Sindhujaa
authors.initials: S
authors.lastname: Vajravel
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, H-6701 Szeged, Hungary. Electronic address: kovacs.laszlo@brc.mta.hu.
authors.forename: Laszlo
authors.initials: L
authors.lastname: Kovacs
authors.affiliation: Centre Algatech, Institute of Microbiology, Academy of Sciences, 37981 Treboň, Czech Republic. Electronic address: knoppova@alga.cz.
authors.forename: Jana
authors.initials: J
authors.lastname: Knoppová
authors.affiliation: Centre Algatech, Institute of Microbiology, Academy of Sciences, 37981 Treboň, Czech Republic. Electronic address: komenda@alga.cz.
authors.forename: Josef
authors.initials: J
authors.lastname: Komenda
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, H-6701 Szeged, Hungary. Electronic address: domonkos.ildiko@brc.mta.hu.
authors.forename: Ildiko
authors.initials: I
authors.lastname: Domonkos
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, H-6701 Szeged, Hungary. Electronic address: kis.mihaly@brc.mta.hu.
authors.forename: Mihaly
authors.initials: M
authors.lastname: Kis
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, H-6701 Szeged, Hungary. Electronic address: gombos.zoltan@brc.mta.hu.
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Gombos
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, H-6701 Szeged, Hungary. Electronic address: laczkodobos.hajnalka@brc.mta.hu.
authors.forename: Hajnalka
authors.initials: H
authors.lastname: Laczko-Dobos
mesh_terms: D000222:Adaptation, Physiological; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects* / Q000648:ultrastructure; D005838:Genotype; D008027:Light; D050356:Lipid Metabolism / Q000235:genetics / Q000528:radiation effects; D008563:Membrane Lipids / Q000378:metabolism / Q000528:radiation effects*; D009154:Mutation; D010641:Phenotype; D010788:Photosynthesis / Q000235:genetics / Q000528:radiation effects*; D045331:Photosystem I Protein Complex / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D013312:Stress, Physiological; D046939:Synechocystis / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects* / Q000648:ultrastructure; D013696:Temperature; D020524:Thylakoids / Q000378:metabolism / Q000528:radiation effects; D013997:Time Factors; D024341:Xanthophylls / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D019207:beta Carotene / Q000378:metabolism / Q000528:radiation effects
chemical_list: D008563:Membrane Lipids; D045331:Photosystem I Protein Complex; D024341:Xanthophylls; D019207:beta Carotene
keywords: Cyanobacteria; Lipid remodeling; Lipid-carotenoid-protein interactions; Photoinhibition; Temperature stress; Xanthophylls