title: Singlet oxygen and non-photochemical quenching contribute to oxidation of the plastoquinone-pool under high light stress in Arabidopsis.
abstract: The redox state of plastoquinone-pool in chloroplasts is crucial for driving many responses to variable environment, from short-term effects to those at the gene expression level. In the present studies, we showed for the first time that the plastoquinone-pool undergoes relatively fast oxidation during high light stress of low light-grown Arabidopsis plants. This oxidation was not caused by photoinhibition of photosystem II, but mainly by singlet oxygen generated in photosystem II and non-photochemical quenching in light harvesting complex antenna of the photosystem, as revealed in experiments with a singlet oxygen scavenger and with Arabidopsis npq4 mutant. The latter mechanism suppresses the influx of electrons to the plastoquinone-pool preventing its excessive reduction. The obtained results are of crucial importance in light of the function of the redox state of the plastoquinone-pool in triggering many high light-stimulated physiological responses of plants.
authors.affiliation: Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland. jerzy.kruk@uj.edu.pl
authors.forename: Jerzy
authors.initials: J
authors.lastname: Kruk
authors.forename: Renata
authors.initials: R
authors.lastname: Szymańska
mesh_terms: D017360:Arabidopsis / Q000502:physiology* / Q000528:radiation effects*; D002734:Chlorophyll / Q000378:metabolism; D004852:Epoxy Compounds / Q000378:metabolism; D008027:Light; D010084:Oxidation-Reduction / Q000528:radiation effects; D055668:Photochemical Processes / Q000528:radiation effects*; D045332:Photosystem II Protein Complex / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism / Q000528:radiation effects; D010971:Plastoquinone / Q000378:metabolism*; D011789:Quantum Theory; D026082:Singlet Oxygen / Q000378:metabolism*; D013312:Stress, Physiological / Q000528:radiation effects*
chemical_list: D004852:Epoxy Compounds; D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D026082:Singlet Oxygen; D010971:Plastoquinone