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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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Stahl-Rommel S, Kalra I, D'Silva S, Hahn MM, Popson D, Cvetkovska M, Morgan-Kiss RM. Cyclic electron flow (CEF) and ascorbate pathway activity provide constitutive photoprotection for the photopsychrophile, Chlamydomonas sp. UWO 241 (renamed Chlamydomonas priscuii). PHOTOSYNTHESIS RESEARCH 2022; 151:235-250. [PMID: 34609708 DOI: 10.1007/s11120-021-00877-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 09/13/2021] [Indexed: 06/13/2023]
Abstract
Under environmental stress, plants and algae employ a variety of strategies to protect the photosynthetic apparatus and maintain photostasis. To date, most studies on stress acclimation have focused on model organisms which possess limited to no tolerance to stressful extremes. We studied the ability of the Antarctic alga Chlamydomonas sp. UWO 241 (UWO 241) to acclimate to low temperature, high salinity or high light. UWO 241 maintained robust growth and photosynthetic activity at levels of temperature (2 °C) and salinity (700 mM NaCl) which were nonpermissive for a mesophilic sister species, Chlamydomonas raudensis SAG 49.72 (SAG 49.72). Acclimation in the mesophile involved classic mechanisms, including downregulation of light harvesting and shifts in excitation energy between photosystem I and II. In contrast, UWO 241 exhibited high rates of PSI-driven cyclic electron flow (CEF) and a larger capacity for nonphotochemical quenching (NPQ). Furthermore, UWO 241 exhibited constitutively high activity of two key ascorbate cycle enzymes, ascorbate peroxidase and glutathione reductase and maintained a large ascorbate pool. These results matched the ability of the psychrophile to maintain low ROS under short-term photoinhibition conditions. We conclude that tight control over photostasis and ROS levels are essential for photosynthetic life to flourish in a native habitat of permanent photooxidative stress. We propose to rename this organism Chlamydomonas priscuii.
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Affiliation(s)
- Sarah Stahl-Rommel
- Department of Microbiology, Miami University, Oxford, OH, 45045, USA
- JES Tech, Houston, TX, 77058, USA
| | - Isha Kalra
- Department of Microbiology, Miami University, Oxford, OH, 45045, USA
| | - Susanna D'Silva
- Department of Microbiology, Miami University, Oxford, OH, 45045, USA
| | - Mark M Hahn
- Department of Microbiology, Miami University, Oxford, OH, 45045, USA
| | - Devon Popson
- Department of Microbiology, Miami University, Oxford, OH, 45045, USA
| | - Marina Cvetkovska
- Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
| | - Rachael M Morgan-Kiss
- Department of Microbiology, Miami University, Oxford, OH, 45045, USA.
- Department of Microbiology, Miami University, 700 E High St., 212 Pearson Hall, Oxford, OH, 45056, USA.
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Hüner NPA, Smith DR, Cvetkovska M, Zhang X, Ivanov AG, Szyszka-Mroz B, Kalra I, Morgan-Kiss R. Photosynthetic adaptation to polar life: Energy balance, photoprotection and genetic redundancy. JOURNAL OF PLANT PHYSIOLOGY 2022; 268:153557. [PMID: 34922115 DOI: 10.1016/j.jplph.2021.153557] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/27/2021] [Accepted: 10/24/2021] [Indexed: 06/14/2023]
Abstract
The persistent low temperature that characterize polar habitats combined with the requirement for light for all photoautotrophs creates a conundrum. The absorption of too much light at low temperature can cause an energy imbalance that decreases photosynthetic performance that has a negative impact on growth and can affect long-term survival. The goal of this review is to survey the mechanism(s) by which polar photoautotrophs maintain cellular energy balance, that is, photostasis to overcome the potential for cellular energy imbalance in their low temperature environments. Photopsychrophiles are photosynthetic organisms that are obligately adapted to low temperature (0⁰- 15 °C) but usually die at higher temperatures (≥20 °C). In contrast, photopsychrotolerant species can usually tolerate and survive a broad range of temperatures (5⁰- 40 °C). First, we summarize the basic concepts of excess excitation energy, energy balance, photoprotection and photostasis and their importance to survival in polar habitats. Second, we compare the photoprotective mechanisms that underlie photostasis and survival in aquatic cyanobacteria and green algae as well as terrestrial Antarctic and Arctic plants. We show that polar photopsychrophilic and photopsychrotolerant organisms attain energy balance at low temperature either through a regulated reduction in the efficiency of light absorption or through enhanced capacity to consume photosynthetic electrons by the induction of O2 as an alternative electron acceptor. Finally, we compare the published genomes of three photopsychrophilic and one photopsychrotolerant alga with five mesophilic green algae including the model green alga, Chlamydomonas reinhardtii. We relate our genomic analyses to photoprotective mechanisms that contribute to the potential attainment of photostasis. Finally, we discuss how the observed genomic redundancy in photopsychrophilic genomes may confer energy balance, photoprotection and resilience to their harsh polar environment. Primary production in aquatic, Antarctic and Arctic environments is dependent on diverse algal and cyanobacterial communities. Although mosses and lichens dominate the Antarctic terrestrial landscape, only two extant angiosperms exist in the Antarctic. The identification of a single 'molecular key' to unravel adaptation of photopsychrophily and photopsychrotolerance remains elusive. Since these photoautotrophs represent excellent biomarkers to assess the impact of global warming on polar ecosystems, increased study of these polar photoautotrophs remains essential.
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Affiliation(s)
- Norman P A Hüner
- Dept. of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, N6A 5B7, Canada.
| | - David R Smith
- Dept. of Biology, University of Western Ontario, London, N6A 5B7, Canada.
| | | | - Xi Zhang
- Dept. of Biology, University of Western Ontario, London, N6A 5B7, Canada.
| | - Alexander G Ivanov
- Dept. of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, N6A 5B7, Canada; Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, 1113, Bulgaria.
| | - Beth Szyszka-Mroz
- Dept. of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, N6A 5B7, Canada.
| | - Isha Kalra
- Dept. of Microbiology, Miami University of Ohio, Oxford, OH, 45056, USA.
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Occurrence, Evolution and Specificities of Iron-Sulfur Proteins and Maturation Factors in Chloroplasts from Algae. Int J Mol Sci 2021; 22:ijms22063175. [PMID: 33804694 PMCID: PMC8003979 DOI: 10.3390/ijms22063175] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 02/25/2021] [Accepted: 03/17/2021] [Indexed: 01/08/2023] Open
Abstract
Iron-containing proteins, including iron-sulfur (Fe-S) proteins, are essential for numerous electron transfer and metabolic reactions. They are present in most subcellular compartments. In plastids, in addition to sustaining the linear and cyclic photosynthetic electron transfer chains, Fe-S proteins participate in carbon, nitrogen, and sulfur assimilation, tetrapyrrole and isoprenoid metabolism, and lipoic acid and thiamine synthesis. The synthesis of Fe-S clusters, their trafficking, and their insertion into chloroplastic proteins necessitate the so-called sulfur mobilization (SUF) protein machinery. In the first part, we describe the molecular mechanisms that allow Fe-S cluster synthesis and insertion into acceptor proteins by the SUF machinery and analyze the occurrence of the SUF components in microalgae, focusing in particular on the green alga Chlamydomonas reinhardtii. In the second part, we describe chloroplastic Fe-S protein-dependent pathways that are specific to Chlamydomonas or for which Chlamydomonas presents specificities compared to terrestrial plants, putting notable emphasis on the contribution of Fe-S proteins to chlorophyll synthesis in the dark and to the fermentative metabolism. The occurrence and evolutionary conservation of these enzymes and pathways have been analyzed in all supergroups of microalgae performing oxygenic photosynthesis.
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Zhang X, Cvetkovska M, Morgan-Kiss R, Hüner NPA, Smith DR. Draft genome sequence of the Antarctic green alga Chlamydomonas sp. UWO241. iScience 2021; 24:102084. [PMID: 33644715 PMCID: PMC7887394 DOI: 10.1016/j.isci.2021.102084] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/08/2020] [Accepted: 01/14/2021] [Indexed: 11/22/2022] Open
Abstract
Antarctica is home to an assortment of psychrophilic algae, which have evolved various survival strategies for coping with their frigid environments. Here, we explore Antarctic psychrophily by examining the ∼212 Mb draft nuclear genome of the green alga Chlamydomonas sp. UWO241, which resides within the water column of a perennially ice-covered, hypersaline lake. Like certain other Antarctic algae, UWO241 encodes a large number (≥37) of ice-binding proteins, putatively originating from horizontal gene transfer. Even more striking, UWO241 harbors hundreds of highly similar duplicated genes involved in diverse cellular processes, some of which we argue are aiding its survival in the Antarctic via gene dosage. Gene and partial gene duplication appear to be an ongoing phenomenon within UWO241, one which might be mediated by retrotransposons. Ultimately, we consider how such a process could be associated with adaptation to extreme environments but explore potential non-adaptive hypotheses as well. Chlamydomonas sp. UWO241 is a green alga originating from Lake Bonney, Antarctica We present a draft nuclear genome sequence of UWO241 (∼212 Mb). The UWO genome contains hundreds of highly similar duplicated genes These duplicates, we argue, might be involved in cold adaptation
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Affiliation(s)
- Xi Zhang
- Department of Biology, University of Western Ontario, London, ON N6A 5B7, Canada
| | - Marina Cvetkovska
- Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | | | - Norman P A Hüner
- Department of Biology, University of Western Ontario, London, ON N6A 5B7, Canada
| | - David Roy Smith
- Department of Biology, University of Western Ontario, London, ON N6A 5B7, Canada
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Young JN, Schmidt K. It's what's inside that matters: physiological adaptations of high-latitude marine microalgae to environmental change. THE NEW PHYTOLOGIST 2020; 227:1307-1318. [PMID: 32391569 DOI: 10.1111/nph.16648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 03/23/2020] [Indexed: 05/13/2023]
Abstract
Marine microalgae within seawater and sea ice fuel high-latitude ecosystems and drive biogeochemical cycles through the fixation and export of carbon, uptake of nutrients, and production and release of oxygen and organic compounds. High-latitude marine environments are characterized by cold temperatures, dark winters and a strong seasonal cycle. Within this environment a number of diverse and dynamic habitats exist, particularly in association with the formation and melt of sea ice, with distinct microalgal communities that transition with the season. Algal physiology is a crucial component, both responding to the dynamic environment and in turn influencing its immediate physicochemical environment. As high-latitude oceans shift into new climate regimes the analysis of seasonal responses may provide insights into how microalgae will respond to long-term environmental change. This review discusses recent developments in our understanding of how the physiology of high-latitude marine microalgae is regulated over a polar seasonal cycle, with a focus on ice-associated (sympagic) algae. In particular, physiologies that impact larger scale processes will be explored, with an aim to improve our understanding of current and future ecosystems and biogeochemical cycles.
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Affiliation(s)
- Jodi N Young
- School of Oceanography, University of Washington, Seattle, WA, 98195, USA
| | - Katrin Schmidt
- School of Oceanography, University of Washington, Seattle, WA, 98195, USA
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Smith DR, Cvetkovska M, Hüner NPA, Morgan-Kiss R. Presence and absence of light-independent chlorophyll biosynthesis among Chlamydomonas green algae in an ice-covered Antarctic lake. Commun Integr Biol 2019; 12:148-150. [PMID: 31666915 PMCID: PMC6802932 DOI: 10.1080/19420889.2019.1676611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/12/2019] [Accepted: 09/13/2019] [Indexed: 12/03/2022] Open
Abstract
The cold, permanently ice-covered waters of Lake Bonney, Antarctica, may seem like an uninviting place for an alga, but they are home to a diversity of photosynthetic life, including Chlamydomonas sp. UWO241, a psychrophile residing in the deep photic zone. Recently, we found that UWO241 has lost the genes responsible for light-independent chlorophyll biosynthesis, which is surprising given that this green alga comes from a light-limited environment and experiences extended periods of darkness during the Antarctic winter. Why discard such a process? We argued that it might be linked to the very high dissolved oxygen concentration of Lake Bonney at the depth at which UWO241 is found. Oxygen is the Achilles’ heel of the key enzyme involved in light-independent chlorophyll biosynthesis: DPOR. If this hypothesis is true, then other algae in Lake Bonney should also be susceptible to losing DPOR, such as Chlamydomonas sp. ICE-MDV, which predominantly resides in the chemocline, a depth with an even higher oxygen concentration than that where UWO241 exists. Here, we report that, contrary to our earlier prediction, ICE-MDV has maintained the genes encoding DPOR. We briefly discuss the implications of this finding in relation to the loss of light-independent chlorophyll synthesis in UWO241.
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Affiliation(s)
- David Roy Smith
- Department of Biology, University of Western Ontario, London, Ontario, Canada
| | - Marina Cvetkovska
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Norman P A Hüner
- Department of Biology, University of Western Ontario, London, Ontario, Canada
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