title: The redox state of the apoplast influences the acclimation of photosynthesis and leaf metabolism to changing irradiance.
abstract: The redox state of the apoplast is largely determined by ascorbate oxidase (AO) activity. The influence of AO activity on leaf acclimation to changing irradiance was explored in wild-type (WT) and transgenic tobacco (Nicotiana tobaccum) lines containing either high [pumpkin AO (PAO)] or low [tobacco AO (TAO)] AO activity at low [low light (LL); 250 μmol m-2s-1] and high [high light (HL); 1600 μmol m-2s-1] irradiance and following the transition from HL to LL. AO activities changed over the photoperiod, particularly in the PAO plants. AO activity had little effect on leaf ascorbate, which was significantly higher under HL than under LL. Apoplastic ascorbate/dehydroascorbate (DHA) ratios and threonate levels were modified by AO activity. Despite decreased levels of transcripts encoding ascorbate synthesis enzymes, leaf ascorbate increased over the first photoperiod following the transition from HL to LL, to much higher levels than LL-grown plants. Photosynthesis rates were significantly higher in the TAO leaves than in WT or PAO plants grown under HL but not under LL. Sub-sets of amino acids and fatty acids were lower in TAO and WT leaves than in the PAO plants under HL, and following the transition to LL. Light acclimation processes are therefore influenced by the apoplastic as well as chloroplastic redox state.
authors.affiliation: Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
authors.forename: Barbara
authors.initials: B
authors.lastname: Karpinska
authors.affiliation: Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.|College of Forestry, Henan Agricultural University, Zhengzhou, 450002, China.
authors.forename: Kaiming
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
authors.forename: Brwa
authors.initials: B
authors.lastname: Rasool
authors.affiliation: Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
authors.forename: Daria
authors.initials: D
authors.lastname: Pastok
authors.affiliation: Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK.
authors.forename: Jenny
authors.initials: J
authors.lastname: Morris
authors.affiliation: Information and Computational Sciences, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK.
authors.forename: Susan R
authors.initials: SR
authors.lastname: Verrall
authors.affiliation: Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK.
authors.forename: Pete E
authors.initials: PE
authors.lastname: Hedley
authors.affiliation: Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK.
authors.forename: Robert D
authors.identifier: 0000-0001-5465-3814
authors.initials: RD
authors.lastname: Hancock
authors.affiliation: Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
authors.forename: Christine H
authors.identifier: 0000-0001-5989-6989
authors.initials: CH
authors.lastname: Foyer
mesh_terms: D000064:Acclimatization; D001204:Ascorbate Oxidase / Q000235:genetics / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism; D008027:Light; D010084:Oxidation-Reduction; D010788:Photosynthesis; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects
chemical_list: D010940:Plant Proteins; D001204:Ascorbate Oxidase; D001205:Ascorbic Acid
keywords: ascorbate; light acclimation; photosynthesis; redox regulation; transcriptome