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Joli N, Concia L, Mocaer K, Guterman J, Laude J, Guerin S, Sciandra T, Bruyant F, Ait-Mohamed O, Beguin M, Forget MH, Bourbousse C, Lacour T, Bailleul B, Nef C, Savoie M, Tremblay JE, Campbell DA, Lavaud J, Schwab Y, Babin M, Bowler C. Hypometabolism to survive the long polar night and subsequent successful return to light in the diatom Fragilariopsis cylindrus. THE NEW PHYTOLOGIST 2024; 241:2193-2208. [PMID: 38095198 DOI: 10.1111/nph.19387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 10/17/2023] [Indexed: 02/09/2024]
Abstract
Diatoms, the main eukaryotic phytoplankton of the polar marine regions, are essential for the maintenance of food chains specific to Arctic and Antarctic ecosystems, and are experiencing major disturbances under current climate change. As such, it is fundamental to understand the physiological mechanisms and associated molecular basis of their endurance during the long polar night. Here, using the polar diatom Fragilariopsis cylindrus, we report an integrative analysis combining transcriptomic, microscopic and biochemical approaches to shed light on the strategies used to survive the polar night. We reveal that in prolonged darkness, diatom cells enter a state of quiescence with reduced metabolic and transcriptional activity, during which no cell division occurs. We propose that minimal energy is provided by respiration and degradation of protein, carbohydrate and lipid stores and that homeostasis is maintained by autophagy in prolonged darkness. We also report internal structural changes that manifest the morphological acclimation of cells to darkness, including the appearance of a large vacuole. Our results further show that immediately following a return to light, diatom cells are able to use photoprotective mechanisms and rapidly resume photosynthesis, demonstrating the remarkable robustness of polar diatoms to prolonged darkness at low temperature.
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Affiliation(s)
- Nathalie Joli
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
| | - Lorenzo Concia
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
| | - Karel Mocaer
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL) & Collaboration for Joint PhD Degree between the European Molecular Biology Laboratory and the Heidelberg University, Faculty of Biosciences, 69117, Heidelberg, Germany
| | - Julie Guterman
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
| | - Juliette Laude
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
| | - Sebastien Guerin
- Takuvik International Research Laboratory, Université Laval (Canada) & CNRS (France), Département de Biologie and Québec-Océan, Université Laval, Québec, QC, G1V 0A6, Canada
| | - Theo Sciandra
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
- Takuvik International Research Laboratory, Université Laval (Canada) & CNRS (France), Département de Biologie and Québec-Océan, Université Laval, Québec, QC, G1V 0A6, Canada
| | - Flavienne Bruyant
- Takuvik International Research Laboratory, Université Laval (Canada) & CNRS (France), Département de Biologie and Québec-Océan, Université Laval, Québec, QC, G1V 0A6, Canada
| | - Ouardia Ait-Mohamed
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
| | - Marine Beguin
- Takuvik International Research Laboratory, Université Laval (Canada) & CNRS (France), Département de Biologie and Québec-Océan, Université Laval, Québec, QC, G1V 0A6, Canada
| | - Marie-Helene Forget
- Takuvik International Research Laboratory, Université Laval (Canada) & CNRS (France), Département de Biologie and Québec-Océan, Université Laval, Québec, QC, G1V 0A6, Canada
| | - Clara Bourbousse
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
| | - Thomas Lacour
- Laboratoire PHYSiologie des micro ALGues (PDG-ODE-PHYTOX-PHYSALG), Centre Atlantique, 44 311, Nantes, France
| | - Benjamin Bailleul
- Laboratory of Chloroplast Biology and Light Sensing in Microalgae, Institut de Biologie Physico Chimique, CNRS, Sorbonne Université, Paris, 75005, France
| | - Charlotte Nef
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
| | - Mireille Savoie
- Département de Biologie, Université Laval, Québec, QC, G1V 0A6, Canada
| | | | | | - Johann Lavaud
- Takuvik International Research Laboratory, Université Laval (Canada) & CNRS (France), Département de Biologie and Québec-Océan, Université Laval, Québec, QC, G1V 0A6, Canada
- UMR 6539 LEMAR-Laboratory of Environmental Marine Sciences, CNRS/Univ Brest/Ifremer/IRD, IUEM-Institut Européen de la Mer, Technopôle Brest-Iroise, rue Dumont d'Urville, 29280, Plouzané, France
| | - Yannick Schwab
- Cell Biology and Biophysics Unit and Electron Microscopy Core Facility, European Molecular Biology Laboratory (EMBL), 69117, Heidelberg, Germany
| | - Marcel Babin
- Takuvik International Research Laboratory, Université Laval (Canada) & CNRS (France), Département de Biologie and Québec-Océan, Université Laval, Québec, QC, G1V 0A6, Canada
| | - Chris Bowler
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
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Ait-Mohamed O, Novák Vanclová AMG, Joli N, Liang Y, Zhao X, Genovesio A, Tirichine L, Bowler C, Dorrell RG. PhaeoNet: A Holistic RNAseq-Based Portrait of Transcriptional Coordination in the Model Diatom Phaeodactylum tricornutum. FRONTIERS IN PLANT SCIENCE 2020; 11:590949. [PMID: 33178253 PMCID: PMC7596299 DOI: 10.3389/fpls.2020.590949] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/15/2020] [Indexed: 05/04/2023]
Abstract
Transcriptional coordination is a fundamental component of prokaryotic and eukaryotic cell biology, underpinning the cell cycle, physiological transitions, and facilitating holistic responses to environmental stress, but its overall dynamics in eukaryotic algae remain poorly understood. Better understanding of transcriptional partitioning may provide key insights into the primary metabolism pathways of eukaryotic algae, which frequently depend on intricate metabolic associations between the chloroplasts and mitochondria that are not found in plants. Here, we exploit 187 publically available RNAseq datasets generated under varying nitrogen, iron and phosphate growth conditions to understand the co-regulatory principles underpinning transcription in the model diatom Phaeodactylum tricornutum. Using WGCNA (Weighted Gene Correlation Network Analysis), we identify 28 merged modules of co-expressed genes in the P. tricornutum genome, which show high connectivity and correlate well with previous microarray-based surveys of gene co-regulation in this species. We use combined functional, subcellular localization and evolutionary annotations to reveal the fundamental principles underpinning the transcriptional co-regulation of genes implicated in P. tricornutum chloroplast and mitochondrial metabolism, as well as the functions of diverse transcription factors underpinning this co-regulation. The resource is publically available as PhaeoNet, an advanced tool to understand diatom gene co-regulation.
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Affiliation(s)
- Ouardia Ait-Mohamed
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Anna M. G. Novák Vanclová
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Nathalie Joli
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Yue Liang
- Department of Oceanography, Dalhousie University, Halifax, NS, Canada
| | - Xue Zhao
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
- Université de Nantes, CNRS, UFIP, UMR 6286, Nantes, France
| | - Auguste Genovesio
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Leila Tirichine
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
- Université de Nantes, CNRS, UFIP, UMR 6286, Nantes, France
- *Correspondence: Leila Tirichine,
| | - Chris Bowler
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
- Chris Bowler,
| | - Richard G. Dorrell
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
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