title: The diatom Phaeodactylum tricornutum adjusts nonphotochemical fluorescence quenching capacity in response to dynamic light via fine-tuned Lhcx and xanthophyll cycle pigment synthesis.
abstract: Diatoms contain a highly flexible capacity to dissipate excessively absorbed light by nonphotochemical fluorescence quenching (NPQ) based on the light-induced conversion of diadinoxanthin (Dd) into diatoxanthin (Dt) and the presence of Lhcx proteins. Their NPQ fine regulation on the molecular level upon a shift to dynamic light conditions is unknown. We investigated the regulation of Dd + Dt amount, Lhcx gene and protein synthesis and NPQ capacity in the diatom Phaeodactylum tricornutum after a change from continuous low light to 3 d of sine (SL) or fluctuating (FL) light conditions. Four P. tricornutum strains with different NPQ capacities due to different expression of Lhcx1 were included. All strains responded to dynamic light comparably, independently of initial NPQ capacity. During SL, NPQ capacity was strongly enhanced due to a gradual increase of Lhcx2 and Dd + Dt amount. During FL, cells enhanced their NPQ capacity on the first day due to increased Dd + Dt, Lhcx2 and Lhcx3; already by the second day light acclimation was accomplished. While quenching efficiency of Dt was strongly lowered during SL conditions, it remained high throughout the whole FL exposure. Our results highlight a more balanced and cost-effective photoacclimation strategy of P. tricornutum under FL than under SL conditions.
authors.affiliation: UMR7266 'LIENSs', CNRS Université de La Rochelle, Institut du Littoral et de l'Environnement, 2 rue Olympe de Gouges, La Rochelle, 17000, France.|Zukunftskolleg, Pflanzliche Ökophysiologie, Universität Konstanz, Konstanz, 78457, Germany.
authors.forename: Bernard
authors.initials: B
authors.lastname: Lepetit
authors.affiliation: UMR7266 'LIENSs', CNRS Université de La Rochelle, Institut du Littoral et de l'Environnement, 2 rue Olympe de Gouges, La Rochelle, 17000, France.
authors.forename: Gautier
authors.initials: G
authors.lastname: Gélin
authors.affiliation: UMR7266 'LIENSs', CNRS Université de La Rochelle, Institut du Littoral et de l'Environnement, 2 rue Olympe de Gouges, La Rochelle, 17000, France.
authors.forename: Mariana
authors.initials: M
authors.lastname: Lepetit
authors.affiliation: Zukunftskolleg, Pflanzliche Ökophysiologie, Universität Konstanz, Konstanz, 78457, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Sturm
authors.affiliation: Zukunftskolleg, Pflanzliche Ökophysiologie, Universität Konstanz, Konstanz, 78457, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Vugrinec
authors.affiliation: Institute of Biosciences and BioResources, CNR, Via P. Castellino 111, Naples, 80131, Italy.|Stazione Zoologica Anton Dohrn Villa Comunale, Naples, 80121, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Rogato
authors.affiliation: Zukunftskolleg, Pflanzliche Ökophysiologie, Universität Konstanz, Konstanz, 78457, Germany.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Kroth
authors.affiliation: Laboratoire de Biologie Computationnelle et Quantitative, Sorbonne Universités, UPMC, Institut de Biologie Paris-Seine, CNRS, 15 rue de l'Ecole de Médecine, Paris, 75006, France.
authors.forename: Angela
authors.initials: A
authors.lastname: Falciatore
authors.affiliation: UMR7266 'LIENSs', CNRS Université de La Rochelle, Institut du Littoral et de l'Environnement, 2 rue Olympe de Gouges, La Rochelle, 17000, France.|Département de Biologie, UMI 3376 TAKUVIK, CNRS/Université Laval, Pavillon Alexandre-Vachon, 1045 avenue de la Médecine, Québec, QC, G1V 0A6, Canada.
authors.forename: Johann
authors.initials: J
authors.lastname: Lavaud
mesh_terms: D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D017377:Diatoms / Q000378:metabolism* / Q000528:radiation effects*; D005453:Fluorescence; D015964:Gene Expression Regulation, Bacterial; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D010788:Photosynthesis / Q000528:radiation effects; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D024341:Xanthophylls / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D045342:Light-Harvesting Protein Complexes; D012333:RNA, Messenger; D024341:Xanthophylls; D002734:Chlorophyll; C033808:diadinoxanthin; C103105:diatoxanthin; D000077194:Chlorophyll A
keywords: Lhcx; Phaeodactylum tricornutum; diatoms; dynamic light; nonphotochemical fluorescence quenching (NPQ); photoprotection; xanthophyll cycle