title: Multisignal control of expression of the LHCX protein family in the marine diatom Phaeodactylum tricornutum.
abstract: Diatoms are phytoplanktonic organisms that grow successfully in the ocean where light conditions are highly variable. Studies of the molecular mechanisms of light acclimation in the marine diatom Phaeodactylum tricornutum show that carotenoid de-epoxidation enzymes and LHCX1, a member of the light-harvesting protein family, both contribute to dissipate excess light energy through non-photochemical quenching (NPQ). In this study, we investigate the role of the other members of the LHCX family in diatom stress responses. Our analysis of available genomic data shows that the presence of multiple LHCX genes is a conserved feature of diatom species living in different ecological niches. Moreover, an analysis of the levels of four P. tricornutum LHCX transcripts in relation to protein expression and photosynthetic activity indicates that LHCXs are differentially regulated under different light intensities and nutrient starvation, mostly modulating NPQ capacity. We conclude that multiple abiotic stress signals converge to regulate the LHCX content of cells, providing a way to fine-tune light harvesting and photoprotection. Moreover, our data indicate that the expansion of the LHCX gene family reflects functional diversification of its members which could benefit cells responding to highly variable ocean environments.
authors.affiliation: Sorbonne Universités, UPMC, Institut de Biologie Paris-Seine, CNRS, Laboratoire de Biologie Computationnelle et Quantitative, 15 rue de l'Ecole de Médecine, 75006 Paris, France.
authors.forename: Lucilla
authors.initials: L
authors.lastname: Taddei
authors.affiliation: Sorbonne Universités, UPMC, Institut de Biologie Paris-Seine, CNRS, Laboratoire de Biologie Computationnelle et Quantitative, 15 rue de l'Ecole de Médecine, 75006 Paris, France Department of Biotechnology, University of Verona, Strada Le Grazie, I-37134 Verona, Italy.
authors.forename: Giulio Rocco
authors.initials: GR
authors.lastname: Stella
authors.affiliation: Sorbonne Universités, UPMC, Institut de Biologie Paris-Seine, CNRS, Laboratoire de Biologie Computationnelle et Quantitative, 15 rue de l'Ecole de Médecine, 75006 Paris, France Institute of Biosciences and BioResources, CNR, Via P. Castellino 111, 80131 Naples, Italy Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Rogato
authors.affiliation: Institut de Biologie Physico-Chimique, UMR 7141 CNRS-UPMC, 13 rue Pierre et Marie Curie, 75005 Paris, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Bailleul
authors.affiliation: Sorbonne Universités, UPMC, Institut de Biologie Paris-Seine, CNRS, Laboratoire de Biologie Computationnelle et Quantitative, 15 rue de l'Ecole de Médecine, 75006 Paris, France.
authors.forename: Antonio Emidio
authors.initials: AE
authors.lastname: Fortunato
authors.affiliation: Sorbonne Universités, UPMC, Institut de Biologie Paris-Seine, CNRS, Laboratoire de Biologie Computationnelle et Quantitative, 15 rue de l'Ecole de Médecine, 75006 Paris, France.
authors.forename: Rossella
authors.initials: R
authors.lastname: Annunziata
authors.affiliation: Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy.
authors.forename: Remo
authors.initials: R
authors.lastname: Sanges
authors.affiliation: Sorbonne Universités, UPMC, Institut de Biologie Paris-Seine, CNRS, Laboratoire de Biologie Computationnelle et Quantitative, 15 rue de l'Ecole de Médecine, 75006 Paris, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Thaler
authors.affiliation: Zukunftskolleg, Department of Plant Ecophysiology, University of Konstanz, D-78457 Konstanz, Germany.
authors.forename: Bernard
authors.initials: B
authors.lastname: Lepetit
authors.affiliation: UMI 3376 TAKUVIK, CNRS/Université Laval, Département de Biologie, Pavillon Alexandre-Vachon, 1045 avenue de la Médecine, Québec (Québec) G1V 0A6, Canada.
authors.forename: Johann
authors.initials: J
authors.lastname: Lavaud
authors.affiliation: Sorbonne Universités, UPMC, Institut de Biologie Paris-Seine, CNRS, Laboratoire de Biologie Computationnelle et Quantitative, 15 rue de l'Ecole de Médecine, 75006 Paris, France.
authors.forename: Marianne
authors.initials: M
authors.lastname: Jaubert
authors.affiliation: Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, Centre National de la Recherche Scientifique (CNRS), Institut National Recherche Agronomique (INRA), Université Grenoble Alpes, Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut de Biosciences et Biotechnologies de Grenoble, (BIG), CEA Grenoble, F-38054 Grenoble cedex 9, France.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Finazzi
authors.affiliation: Sorbonne Universités, UPMC, Institut de Biologie Paris-Seine, CNRS, Laboratoire de Biologie Computationnelle et Quantitative, 15 rue de l'Ecole de Médecine, 75006 Paris, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Bouly
authors.affiliation: Sorbonne Universités, UPMC, Institut de Biologie Paris-Seine, CNRS, Laboratoire de Biologie Computationnelle et Quantitative, 15 rue de l'Ecole de Médecine, 75006 Paris, France angela.falciatore@upmc.fr.
authors.forename: Angela
authors.initials: A
authors.lastname: Falciatore
mesh_terms: D020418:Algal Proteins / Q000235:genetics* / Q000378:metabolism; D017377:Diatoms / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D045342:Light-Harvesting Protein Complexes / Q000235:genetics* / Q000378:metabolism; D010788:Photosynthesis; D010839:Phytoplankton / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D020418:Algal Proteins; D045342:Light-Harvesting Protein Complexes
keywords: Dark; LHCX; gene expression; iron starvation; light; marine diatom; nitrogen starvation; non-photochemical quenching.