1
|
Volpe C, Nymark M, Andersen T, Winge P, Lavaud J, Vadstein O. Skeletonema marinoi ecotypes show specific habitat-related responses to fluctuating light supporting high potential for growth under photobioreactor light regime. THE NEW PHYTOLOGIST 2024. [PMID: 38736026 DOI: 10.1111/nph.19788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 04/09/2024] [Indexed: 05/14/2024]
Abstract
Diatoms are a diverse group of phytoplankton usually dominating areas characterized by rapidly shifting light conditions. Because of their high growth rates and interesting biochemical profile, their biomass is considered for various commercial applications. This study aimed at identifying strains with superior growth in a photobioreactor (PBR) by screening the natural intraspecific diversity of ecotypes isolated from different habitats. We investigated the effect of PBR light fluctuating on a millisecond scale (FL, simulating the light in a PBR) on 19 ecotypes of the diatom Skeletonema marinoi isolated from the North Sea-Baltic Sea area. We compare growth, pigment ratios, phylogeny, photo-physiological variables and photoacclimation strategies between all strains and perform qPCR and absorption spectra analysis on a subset of strains. Our results show that the ecotypes responded differently to FL, and have contrasting photo-physiological and photoprotective strategies. The strains from Kattegat performed better in FL, and shared common photoacclimation and photoprotection strategies that are the results of adaptation to the specific light climate of the Kattegat area. The strains that performed better with FL conditions had a high light (HL)-acclimated phenotype coupled with unique nonphotochemical quenching features. Based on their characteristics, three strains were identified as good candidates for growth in PBRs.
Collapse
Affiliation(s)
- Charlotte Volpe
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, N-7491, Trondheim, Norway
- Department of Fisheries and New Biomarine Industry, SINTEF Ocean, N-7465, Trondheim, Norway
| | - Marianne Nymark
- Department of Fisheries and New Biomarine Industry, SINTEF Ocean, N-7465, Trondheim, Norway
- Department of Biology, Norwegian University of Science and Technology, N-7491, Trondheim, Norway
| | - Tom Andersen
- Department of Biosciences, Section for Aquatic Biology and Toxicology (AQUA), University of Oslo, N-0316, Oslo, Norway
| | - Per Winge
- Department of Biology, Norwegian University of Science and Technology, N-7491, Trondheim, Norway
| | - Johann Lavaud
- LEMAR-Laboratory of Marine Environmental Sciences, UMR6539 CNRS, Univ Brest, Ifremer, IRD, Institut Européen de la Mer, Technopôle Brest-Iroise, rue Dumont d'Urville, Plouzané, 29280, France
| | - Olav Vadstein
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, N-7491, Trondheim, Norway
| |
Collapse
|
2
|
Chaumier T, Yang F, Manirakiza E, Ait-Mohamed O, Wu Y, Chandola U, Jesus B, Piganeau G, Groisillier A, Tirichine L. Genome-wide assessment of genetic diversity and transcript variations in 17 accessions of the model diatom Phaeodactylum tricornutum. ISME COMMUNICATIONS 2024; 4:ycad008. [PMID: 38304080 PMCID: PMC10833087 DOI: 10.1093/ismeco/ycad008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/01/2023] [Accepted: 12/13/2023] [Indexed: 02/03/2024]
Abstract
Diatoms, a prominent group of phytoplankton, have a significant impact on both the oceanic food chain and carbon sequestration, thereby playing a crucial role in regulating the climate. These highly diverse organisms show a wide geographic distribution across various latitudes. In addition to their ecological significance, diatoms represent a vital source of bioactive compounds that are widely used in biotechnology applications. In the present study, we investigated the genetic and transcriptomic diversity of 17 accessions of the model diatom Phaeodactylum tricornutum including those sampled a century ago as well as more recently collected accessions. The analysis of the data reveals a higher genetic diversity and the emergence of novel clades, indicating an increasing diversity within the P. tricornutum population structure, compared to the previous study and a persistent long-term balancing selection of genes in old and newly sampled accessions. However, the study did not establish a clear link between the year of sampling and genetic diversity, thereby, rejecting the hypothesis of loss of heterozygoty in cultured strains. Transcript analysis identified novel transcript including noncoding RNA and other categories of small RNA such as PiwiRNAs. Additionally, transcripts analysis using differential expression as well as Weighted Gene Correlation Network Analysis has provided evidence that the suppression or downregulation of genes cannot be solely attributed to loss-of-function mutations. This implies that other contributing factors, such as epigenetic modifications, may play a crucial role in regulating gene expression. Our study provides novel genetic resources, which are now accessible through the platform PhaeoEpiview (https://PhaeoEpiView.univ-nantes.fr), that offer both ease of use and advanced tools to further investigate microalgae biology and ecology, consequently enriching our current understanding of these organisms.
Collapse
Affiliation(s)
| | - Feng Yang
- Nantes Université, CNRS, US2B, UMR 6286, Nantes F-44000, France
| | - Eric Manirakiza
- Nantes Université, CNRS, US2B, UMR 6286, Nantes F-44000, France
| | - Ouardia Ait-Mohamed
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, Paris 75005, France
| | - Yue Wu
- Nantes Université, CNRS, US2B, UMR 6286, Nantes F-44000, France
| | - Udita Chandola
- Nantes Université, CNRS, US2B, UMR 6286, Nantes F-44000, France
| | - Bruno Jesus
- Institut des Substances et Organismes de la Mer, ISOMer, Nantes Université, UR 2160, Nantes F-44000, France
| | - Gwenael Piganeau
- Sorbonne Université, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes, LBBM, F-66650 Banyuls-sur-Mer, France
| | | | - Leila Tirichine
- Nantes Université, CNRS, US2B, UMR 6286, Nantes F-44000, France
| |
Collapse
|
3
|
Im SH, Madhuri S, Lepetit B, Kroth PG. Functional demonstration of Aureochrome 1a proteasomal degradation after blue light incubation in the diatom Phaeodactylum tricornutum. JOURNAL OF PLANT PHYSIOLOGY 2024; 292:154148. [PMID: 38101100 DOI: 10.1016/j.jplph.2023.154148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 11/15/2023] [Accepted: 11/27/2023] [Indexed: 12/17/2023]
Abstract
Aureochromes (AUREOs) are both blue light photoreceptors and transcription factors found in diatoms and related algal groups that play a critical role in regulating gene and cell physiology. One of the AUREOs in the diatom Phaeodactylum tricornutum, PtAUREO1a, has been demonstrated to significantly influence global cellular transcription upon blue light exposure. PtAUREO1a itself is highly regulated on the gene transcription level, depending on the light conditions. However, little is known about the proteostasis of PtAUREO1a in vivo. In this study, we used quantitative immunoblot analysis to examine PtAUREO1a levels under different light conditions as well as in the presence of inhibitors for translation and proteolysis. Our results demonstrate that PtAUREO1a is rapidly degraded in response to blue light exposure after red light acclimation, while the protein has an extended protein half-life in white light conditions. Moreover, the data provide the first in vivo evidence for a functional ubiquitin-proteasome system in the model diatom P. tricornutum. Our findings provide a theoretical basis for studies on protein degradation mechanisms and the regulation of PtAUREO1a, suggesting that changing light conditions can have an impact on the PtAUREO1a protein amount by directly affecting its protein stability.
Collapse
Affiliation(s)
- Soo Hyun Im
- Plant Ecophysiology, Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany.
| | - Shvaita Madhuri
- Plant Ecophysiology, Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany
| | - Bernard Lepetit
- Plant Ecophysiology, Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany; Molecular Stress Physiology, Institute of Biological Sciences, University of Rostock, 18059, Rostock, Germany
| | - Peter G Kroth
- Plant Ecophysiology, Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany.
| |
Collapse
|
4
|
Gomes KM, Nunn BL, Chappell PD, Jenkins BD. Subcellular proteomics for determining iron-limited remodeling of plastids in the model diatom Thalassiosira pseudonana (Bacillariophyta). JOURNAL OF PHYCOLOGY 2023; 59:1085-1099. [PMID: 37615442 DOI: 10.1111/jpy.13379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 07/13/2023] [Accepted: 07/14/2023] [Indexed: 08/25/2023]
Abstract
Diatoms are important primary producers in the world's oceans, yet their growth is constrained in large regions by low bioavailable iron (Fe). Low-Fe stress-induced limitation of primary production is due to requirements for Fe in components of essential metabolic pathways including photosynthesis and other chloroplast plastid functions. Studies have shown that under low-Fe stress, diatoms alter plastid-specific processes, including components of electron transport. These physiological changes suggest changes of protein content and in protein abundances within the diatom plastid. While in silico predictions provide putative information on plastid-localized proteins, knowledge of diatom plastid proteins remains limited in comparison to well-studied model photosynthetic organisms. To address this, we employed shotgun proteomics to investigate the proteome of subcellular plastid-enriched fractions from Thalassiosira pseudonana to gain a better understanding of how the plastid proteome is remodeled in response to Fe limitation. Using mass spectrometry-based peptide identification and quantification, we analyzed T. pseudonana grown under Fe-replete and -limiting conditions. Through these analyses, we inferred the relative quantities of each protein, revealing that Fe limitation regulates major metabolic pathways in the plastid, including the Calvin cycle. Additionally, we observed changes in the expression of light-harvesting proteins. In silico localization predictions of proteins identified in this plastid-enriched proteome allowed for an in-depth comparison of theoretical versus observed plastid-localization, providing evidence for the potential of additional protein import pathways into the diatom plastid.
Collapse
Affiliation(s)
- Kristofer M Gomes
- Department of Biological Sciences, University of Rhode Island, Rhode Island, Kingston, USA
| | - Brook L Nunn
- Department of Genome Sciences, University of Washington, Washington, Seattle, USA
| | - P Dreux Chappell
- College of Marine Science, University of South Florida, Florida, St. Petersburg, USA
| | - Bethany D Jenkins
- Department of Cell and Molecular Biology, University of Rhode Island, Rhode Island, Kingston, USA
- Graduate School of Oceanography, University of Rhode Island, Rhode Island, Narragansett, USA
| |
Collapse
|
5
|
Du J, Izquierdo D, Xu HF, Beisner B, Lavaud J, Ohlund L, Sleno L, Juneau P. Responses to herbicides of Arctic and temperate microalgae grown under different light intensities. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 333:121985. [PMID: 37301455 DOI: 10.1016/j.envpol.2023.121985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 06/12/2023]
Abstract
In aquatic ecosystems, microalgae are exposed to light fluctuations at different frequencies due to daily and seasonal changes. Although concentrations of herbicides are lower in Arctic than in temperate regions, atrazine and simazine, are increasingly found in northern aquatic systems because of long-distance aerial dispersal of widespread applications in the south and antifouling biocides used on ships. The toxic effects of atrazine on temperate microalgae are well documented, but very little is known about their effects on Arctic marine microalgae in relation to their temperate counterparts after light adaptation to variable light intensities. We therefore investigated the impacts of atrazine and simazine on photosynthetic activity, PSII energy fluxes, pigment content, photoprotective ability (NPQ), and reactive oxygen species (ROS) content under three light intensities. The goal was to better understand differences in physiological responses to light fluctuations between Arctic and temperate microalgae and to determine how these different characteristics affect their responses to herbicides. The Arctic diatom Chaetoceros showed stronger light adaptation capacity than the Arctic green algae Micromonas. Atrazine and simazine inhibited the growth and photosynthetic electron transport, affected the pigment content, and disturbed the energy balance between light absorption and utilization. As a result, during high light adaptation and in the presence of herbicides, photoprotective pigments were synthesized and NPQ was highly activated. Nevertheless, these protective responses were insufficient to prevent oxidative damage caused by herbicides in both species from both regions, but at different extent depending on the species. Our study demonstrates that light is important in regulating herbicide toxicity in both Arctic and temperate microalgal strains. Moreover, eco-physiological differences in light responses are likely to support changes in the algal community, especially as the Arctic ocean becomes more polluted and bright with continued human impacts.
Collapse
Affiliation(s)
- Juan Du
- Department of Biological Sciences, Université du Québec à Montréal-GRIL-TOXEN, Succ Centre-Ville, Montréal, Canada
| | - Disney Izquierdo
- Department of Biological Sciences, Université du Québec à Montréal-GRIL-EcotoQ-TOXEN, Succ Centre-Ville, Montréal, Canada
| | - Hai-Feng Xu
- School of Life Sciences, and Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan, 430079, Hubei, China
| | - Beatrix Beisner
- Department of Biological Sciences, Groupe de Recherche Interuniversitaire en Limnologie (GRIL), Université du Québec à Montréal, Canada
| | - Johann Lavaud
- TAKUVIK International Research Laboratory IRL3376, Université Laval (Canada) - CNRS (France), Pavillon Alexandre-Vachon, 1045 Av. de la Médecine, Local 2064, G1V 0A6, Québec, Canada; LEMAR-Laboratory of Environmental Marine Sciences, UMR6539, CNRS/Univ Brest/Ifremer/IRD, Institut Universitaire Européen de La Mer, Technopôle Brest-Iroise, Rue Dumont d'Urville, 29280, Plouzané, France
| | - Leanne Ohlund
- Chemistry Department, Université du Québec à Montréal-EcotoQ-TOXEN, Succ Centre-Ville, Montreal, Quebec, H3C 3P8, Canada
| | - Lekha Sleno
- Chemistry Department, Université du Québec à Montréal-EcotoQ-TOXEN, Succ Centre-Ville, Montreal, Quebec, H3C 3P8, Canada
| | - Philippe Juneau
- Department of Biological Sciences, Université du Québec à Montréal-GRIL-EcotoQ-TOXEN, Succ Centre-Ville, Montréal, Canada.
| |
Collapse
|
6
|
Cecchin M, Simicevic J, Chaput L, Hernandez Gil M, Girolomoni L, Cazzaniga S, Remacle C, Hoeng J, Ivanov NV, Titz B, Ballottari M. Acclimation strategies of the green alga Chlorella vulgaris to different light regimes revealed by physiological and comparative proteomic analyses. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4540-4558. [PMID: 37155956 DOI: 10.1093/jxb/erad170] [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: 02/27/2023] [Accepted: 05/05/2023] [Indexed: 05/10/2023]
Abstract
Acclimation to different light regimes is at the basis of survival for photosynthetic organisms, regardless of their evolutionary origin. Previous research efforts largely focused on acclimation events occurring at the level of the photosynthetic apparatus and often highlighted species-specific mechanisms. Here, we investigated the consequences of acclimation to different irradiances in Chlorella vulgaris, a green alga that is one of the most promising species for industrial application, focusing on both photosynthetic and mitochondrial activities. Moreover, proteomic analysis of cells acclimated to high light (HL) or low light (LL) allowed identification of the main targets of acclimation in terms of differentially expressed proteins. The results obtained demonstrate photosynthetic adaptation to HL versus LL that was only partially consistent with previous findings in Chlamydomonas reinhardtii, a model organism for green algae, but in many cases similar to vascular plant acclimation events. Increased mitochondrial respiration measured in HL-acclimated cells mainly relied on alternative oxidative pathway dissipating the excessive reducing power produced due to enhanced carbon flow. Finally, proteins involved in cell metabolism, intracellular transport, gene expression, and signaling-including a heliorhodopsin homolog-were identified as strongly differentially expressed in HL versus LL, suggesting their key roles in acclimation to different light regimes.
Collapse
Affiliation(s)
- Michela Cecchin
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Jovan Simicevic
- PMI R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchâtel, Switzerland
| | - Louise Chaput
- PMI R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchâtel, Switzerland
| | - Manuel Hernandez Gil
- PMI R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchâtel, Switzerland
| | - Laura Girolomoni
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Stefano Cazzaniga
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Claire Remacle
- Genetics and Physiology of Microalgae, InBios/Phytosystems Research Unit, University of Liège, 4000 Liège, Belgium
| | - Julia Hoeng
- PMI R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchâtel, Switzerland
| | - Nikolai V Ivanov
- PMI R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchâtel, Switzerland
| | - Bjoern Titz
- PMI R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchâtel, Switzerland
| | - Matteo Ballottari
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| |
Collapse
|
7
|
Kan C, Zhao Y, Sun KM, Tang X, Zhao Y. The inhibition and recovery mechanisms of the diatom Phaeodactylum tricornutum in response to high light stress - A study combining physiological and transcriptional analysis. JOURNAL OF PHYCOLOGY 2023; 59:418-431. [PMID: 36798977 DOI: 10.1111/jpy.13323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 05/28/2023]
Abstract
By combining physiological/biochemical and transcriptional analysis, the inhibition and recovery mechanisms of Phaeodactylum tricornutum in response to extreme high light stress (1300 μmol photons · m-2 · s-1 ) were elucidated. The population growth was inhibited in the first 24 h and started to recover from 48 h. At 24 h, photoinhibition was exhibited as the changes of PSII photosynthetic parameters and decrease in cellular pigments, corresponding to the downregulation of genes encoding light-harvesting complex and pigments synthesis. Changes in those photosynthetic parameters and genes were kept until 96 h, indicating that the decrease of light absorption abilities might be one strategy for photoacclimation. In the meanwhile, we observed elevated cellular ROS levels, dead cells proportions, and upregulation of genes encoding antioxidant materials and proteasome pathway at 24 h. Those stress-related parameters and genes recovered to the controls at 96 h, indicating a stable intracellular environment after photoacclimation. Finally, genes involving carbon metabolisms were upregulated from 24 to 96 h, which ensured the energy supply for keeping high base and nucleotide excision repair abilities, leading to the recovery of cell cycle progression. We concluded that P. tricornutum could overcome photoinhibition by decreasing light-harvesting abilities, enhancing carbon metabolisms, activating anti-oxidative functions, and elevating repair abilities. The parameters of light harvesting, carbon metabolisms, and repair processes were responsible for the recovery phase, which could be considered long-term adaptive strategies for diatoms under high light stress.
Collapse
Affiliation(s)
- Chengxiang Kan
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, China
| | - Yirong Zhao
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, China
| | - Kai-Ming Sun
- Institute of Oceanographic Instrumentation, Qilu University of Technology (Shandong Academy of Sciences), Qingdao, China
| | - Xuexi Tang
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Yan Zhao
- College of Marine Life Sciences, Department of Marine Ecology, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| |
Collapse
|
8
|
Agarwal A, Levitan O, Cruz de Carvalho H, Falkowski PG. Light-dependent signal transduction in the marine diatom Phaeodactylum tricornutum. Proc Natl Acad Sci U S A 2023; 120:e2216286120. [PMID: 36897974 PMCID: PMC10089185 DOI: 10.1073/pnas.2216286120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 02/09/2023] [Indexed: 03/12/2023] Open
Abstract
Unlike most higher plants, unicellular algae can acclimate to changes in irradiance on time scales of hours to a few days. The process involves an enigmatic signaling pathway originating in the plastid that leads to coordinated changes in plastid and nuclear gene expression. To deepen our understanding of this process, we conducted functional studies to examine how the model diatom, Phaeodactylum tricornutum, acclimates to low light and sought to identify the molecules responsible for the phenomenon. We show that two transformants with altered expression of two putative signal transduction molecules, a light-specific soluble kinase and a plastid transmembrane protein, that appears to be regulated by a long noncoding natural antisense transcript, arising from the opposite strand, are physiologically incapable of photoacclimation. Based on these results, we propose a working model of the retrograde feedback in the signaling and regulation of photoacclimation in a marine diatom.
Collapse
Affiliation(s)
- Ananya Agarwal
- Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ08901
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ08901
| | - Orly Levitan
- Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ08901
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ08901
| | - Helena Cruz de Carvalho
- Institut de Biologie de l’ENS, Ecole normale supérieure, CNRS, Inserm, Université Paris Sciences & Letters, Paris75005, France
- Faculté des Sciences et Technologie, Université Paris Est-Créteil94000Créteil, France
| | - Paul G. Falkowski
- Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ08901
- Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ08854
| |
Collapse
|
9
|
Light-response in two clonal strains of the haptophyte Tisochrysis lutea: Evidence for different photoprotection strategies. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
|
10
|
Yu G, Nakajima K, Gruber A, Rio Bartulos C, Schober AF, Lepetit B, Yohannes E, Matsuda Y, Kroth PG. Mitochondrial phosphoenolpyruvate carboxylase contributes to carbon fixation in the diatom Phaeodactylum tricornutum at low inorganic carbon concentrations. THE NEW PHYTOLOGIST 2022; 235:1379-1393. [PMID: 35596716 DOI: 10.1111/nph.18268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 04/21/2022] [Indexed: 06/15/2023]
Abstract
Photosynthetic carbon fixation is often limited by CO2 availability, which led to the evolution of CO2 concentrating mechanisms (CCMs). Some diatoms possess CCMs that employ biochemical fixation of bicarbonate, similar to C4 plants, but whether biochemical CCMs are commonly found in diatoms is a subject of debate. In the diatom Phaeodactylum tricornutum, phosphoenolpyruvate carboxylase (PEPC) is present in two isoforms, PEPC1 in the plastids and PEPC2 in the mitochondria. We used real-time quantitative polymerase chain reaction, Western blots, and enzymatic assays to examine PEPC expression and PEPC activity, under low and high concentrations of dissolved inorganic carbon (DIC). We generated and analyzed individual knockout cell lines of PEPC1 and PEPC2, as well as a PEPC1/2 double-knockout strain. While we could not detect an altered phenotype in the PEPC1 knockout strains at ambient, low or high DIC concentrations, PEPC2 and the double-knockout strains grown under ambient air or lower DIC availability conditions showed reduced growth and photosynthetic affinity for DIC while behaving similarly to wild-type (WT) cells at high DIC concentrations. These mutants furthermore exhibited significantly lower 13 C/12 C ratios compared to the WT. Our data imply that in P. tricornutum at least parts of the CCM rely on biochemical bicarbonate fixation catalyzed by the mitochondrial PEPC2.
Collapse
Affiliation(s)
- Guilan Yu
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany
| | - Kensuke Nakajima
- Department of Bioscience, School of Biological and Environmental Sciences, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
| | - Ansgar Gruber
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05, České Budějovice, Czech Republic
| | | | | | - Bernard Lepetit
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany
| | | | - Yusuke Matsuda
- Department of Bioscience, School of Biological and Environmental Sciences, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
| | - Peter G Kroth
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany
| |
Collapse
|
11
|
Pajot A, Lavaud J, Carrier G, Garnier M, Saint-Jean B, Rabilloud N, Baroukh C, Bérard JB, Bernard O, Marchal L, Nicolau E. The Fucoxanthin Chlorophyll a/c-Binding Protein in Tisochrysis lutea: Influence of Nitrogen and Light on Fucoxanthin and Chlorophyll a/c-Binding Protein Gene Expression and Fucoxanthin Synthesis. FRONTIERS IN PLANT SCIENCE 2022; 13:830069. [PMID: 35251102 PMCID: PMC8891753 DOI: 10.3389/fpls.2022.830069] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 01/20/2022] [Indexed: 06/13/2023]
Abstract
We observed differences in lhc classification in Chromista. We proposed a classification of the lhcf family with two groups specific to haptophytes, one specific to diatoms, and one specific to seaweeds. Identification and characterization of the Fucoxanthin and Chlorophyll a/c-binding Protein (FCP) of the haptophyte microalgae Tisochrysis lutea were performed by similarity analysis. The FCP family contains 52 lhc genes in T. lutea. FCP pigment binding site candidates were characterized on Lhcf protein monomers of T. lutea, which possesses at least nine chlorophylls and five fucoxanthin molecules, on average, per monomer. The expression of T. lutea lhc genes was assessed during turbidostat and chemostat experiments, one with constant light (CL) and changing nitrogen phases, the second with a 12 h:12 h sinusoidal photoperiod and changing nitrogen phases. RNA-seq analysis revealed a dynamic decrease in the expression of lhc genes with nitrogen depletion. We observed that T. lutea lhcx2 was only expressed at night, suggesting that its role is to protect \cells from return of light after prolonged darkness exposure.
Collapse
Affiliation(s)
- Anne Pajot
- IFREMER, Physiology and Biotechnology of Algae Laboratory, Nantes, France
| | - Johann Lavaud
- LEMAR-Laboratoire des Sciences de l’Environnement Marin, UMR 6539, CNRS/Univ Brest/Ifremer/IRD, Institut Universitaire Européen de la Mer, Technopôle Brest-Iroise, Plouzané, France
| | - Gregory Carrier
- IFREMER, Physiology and Biotechnology of Algae Laboratory, Nantes, France
| | - Matthieu Garnier
- IFREMER, Physiology and Biotechnology of Algae Laboratory, Nantes, France
| | - Bruno Saint-Jean
- IFREMER, Physiology and Biotechnology of Algae Laboratory, Nantes, France
| | - Noémie Rabilloud
- IFREMER, Physiology and Biotechnology of Algae Laboratory, Nantes, France
| | - Caroline Baroukh
- IFREMER, Physiology and Biotechnology of Algae Laboratory, Nantes, France
| | | | - Olivier Bernard
- Université Côte d’Azur, Biocore, INRIA, CNRS, Sorbonne Université (LOV, UMR 7093), Sophia-Antipolis, France
| | | | - Elodie Nicolau
- IFREMER, Physiology and Biotechnology of Algae Laboratory, Nantes, France
| |
Collapse
|
12
|
Giovagnetti V, Jaubert M, Shukla MK, Ungerer P, Bouly JP, Falciatore A, Ruban AV. Biochemical and molecular properties of LHCX1, the essential regulator of dynamic photoprotection in diatoms. PLANT PHYSIOLOGY 2022; 188:509-525. [PMID: 34595530 PMCID: PMC8774712 DOI: 10.1093/plphys/kiab425] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 08/06/2021] [Indexed: 05/24/2023]
Abstract
Light harvesting is regulated by a process triggered by the acidification of the thylakoid lumen, known as nonphotochemical "energy-dependent quenching" (qE). In diatoms, qE is controlled by the light-harvesting complex (LHC) protein LHCX1, while the LHC stress-related (LHCSR) and photosystem II subunit S proteins are essential for green algae and plants, respectively. Here, we report a biochemical and molecular characterization of LHCX1 to investigate its role in qE. We found that, when grown under intermittent light, Phaeodactylum tricornutum forms very large qE, due to LHCX1 constitutive upregulation. This "super qE" is abolished in LHCX1 knockout mutants. Biochemical and spectroscopic analyses of LHCX1 reveal that this protein might differ in the character of binding pigments relative to the major pool of light-harvesting antenna proteins. The possibility of transient pigment binding or not binding pigments at all is discussed. Targeted mutagenesis of putative protonatable residues (D95 and E205) in transgenic P. tricornutum lines does not alter qE capacity, showing that they are not involved in sensing lumen pH, differently from residues conserved in LHCSR3. Our results suggest functional divergence between LHCX1 and LHCSR3 in qE modulation. We propose that LHCX1 evolved independently to facilitate dynamic tracking of light fluctuations in turbulent waters. The evolution of LHCX(-like) proteins in organisms with secondary red plastids, such as diatoms, might have conferred a selective advantage in the control of dynamic photoprotection, ultimately resulting in their ecological success.
Collapse
Affiliation(s)
- Vasco Giovagnetti
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Marianne Jaubert
- Laboratoire de Biologie du Chloroplaste et Perception de la Lumière Chez les Micro-algues, UMR7141, CNRS, Sorbonne Université, Institut de Biologie Physico-Chimique, Paris 75005, France
| | - Mahendra K Shukla
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Petra Ungerer
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Jean-Pierre Bouly
- Laboratoire de Biologie du Chloroplaste et Perception de la Lumière Chez les Micro-algues, UMR7141, CNRS, Sorbonne Université, Institut de Biologie Physico-Chimique, Paris 75005, France
| | - Angela Falciatore
- Laboratoire de Biologie du Chloroplaste et Perception de la Lumière Chez les Micro-algues, UMR7141, CNRS, Sorbonne Université, Institut de Biologie Physico-Chimique, Paris 75005, France
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| |
Collapse
|
13
|
Buck JM, Wünsch M, Schober AF, Kroth PG, Lepetit B. Impact of Lhcx2 on Acclimation to Low Iron Conditions in the Diatom Phaeodactylum tricornutum. FRONTIERS IN PLANT SCIENCE 2022; 13:841058. [PMID: 35371185 PMCID: PMC8967352 DOI: 10.3389/fpls.2022.841058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 01/24/2022] [Indexed: 05/09/2023]
Abstract
Iron is a cofactor of photosystems and electron carriers in the photosynthetic electron transport chain. Low concentrations of dissolved iron are, therefore, the predominant factor that limits the growth of phototrophs in large parts of the open sea like the Southern Ocean and the North Pacific, resulting in "high nutrient-low chlorophyll" (HNLC) areas. Diatoms are among the most abundant microalgae in HNLC zones. Besides efficient iron uptake mechanisms, efficient photoprotection might be one of the key traits enabling them to outcompete other algae in HNLC regions. In diatoms, Lhcx proteins play a crucial role in one of the main photoprotective mechanisms, the energy-dependent fluorescence quenching (qE). The expression of Lhcx proteins is strongly influenced by various environmental triggers. We show that Lhcx2 responds specifically and in a very sensitive manner to iron limitation in the diatom Phaeodactylum tricornutum on the same timescale as the known iron-regulated genes ISIP1 and CCHH11. By comparing Lhcx2 knockout lines with wild type cells, we reveal that a strongly increased qE under iron limitation is based on the upregulation of Lhcx2. Other observed iron acclimation phenotypes in P. tricornutum include a massively reduced chlorophyll a content/cell, a changed ratio of light harvesting and photoprotective pigments per chlorophyll a, a decreased amount of photosystem II and photosystem I cores, an increased functional photosystem II absorption cross section, and decoupled antenna complexes. H2O2 formation at photosystem I induced by high light is lowered in iron-limited cells, while the amount of total reactive oxygen species is rather increased. Our data indicate a possible reduction in singlet oxygen by Lhcx2-based qE, while the other iron acclimation phenotype parameters monitored are not affected by the amount of Lhcx2 and qE.
Collapse
|
14
|
Buck JM, Kroth PG, Lepetit B. Identification of sequence motifs in Lhcx proteins that confer qE-based photoprotection in the diatom Phaeodactylum tricornutum. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 108:1721-1734. [PMID: 34651379 DOI: 10.1111/tpj.15539] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 08/11/2021] [Indexed: 05/08/2023]
Abstract
Photosynthetic organisms in nature often experience light fluctuations. While low light conditions limit the energy uptake by algae, light absorption exceeding the maximal rate of photosynthesis may go along with enhanced formation of potentially toxic reactive oxygen species. To preempt high light-induced photodamage, photosynthetic organisms evolved numerous photoprotective mechanisms. Among these, energy-dependent fluorescence quenching (qE) provides a rapid mechanism to dissipate thermally the excessively absorbed energy. Diatoms thrive in all aquatic environments and thus belong to the most important primary producers on earth. qE in diatoms is provided by a concerted action of Lhcx proteins and the xanthophyll cycle pigment diatoxanthin. While the exact Lhcx activation mechanism of diatom qE is unknown, two lumen-exposed acidic amino acids within Lhcx proteins were proposed to function as regulatory switches upon light-induced lumenal acidification. By introducing a modified Lhcx1 lacking these amino acids into a Phaeodactylum tricornutum Lhcx1-null qE knockout line, we demonstrate that qE is unaffected by these two amino acids. Based on sequence comparisons with Lhcx4, being incapable of providing qE, we perform domain swap experiments of Lhcx4 with Lhcx1 and identify two peptide motifs involved in conferring qE. Within one of these motifs, we identify a tryptophan residue with a major influence on qE establishment. This tryptophan residue is located in close proximity to the diadinoxanthin/diatoxanthin-binding site based on the recently revealed diatom Lhc crystal structure. Our findings provide a structural explanation for the intimate link of Lhcx and diatoxanthin in providing qE in diatoms.
Collapse
Affiliation(s)
- Jochen M Buck
- Plant Ecophysiology, Department of Biology, University of Konstanz, Konstanz, 78457, Germany
| | - Peter G Kroth
- Plant Ecophysiology, Department of Biology, University of Konstanz, Konstanz, 78457, Germany
| | - Bernard Lepetit
- Plant Ecophysiology, Department of Biology, University of Konstanz, Konstanz, 78457, Germany
| |
Collapse
|
15
|
Chrysafoudi A, Maity S, Kleinekathöfer U, Daskalakis V. Robust Strategy for Photoprotection in the Light-Harvesting Antenna of Diatoms: A Molecular Dynamics Study. J Phys Chem Lett 2021; 12:9626-9633. [PMID: 34585934 DOI: 10.1021/acs.jpclett.1c02498] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Diatoms generate a large portion of the oxygen produced on earth due to their exceptional light-harvesting properties involving fucoxanthin and chlorophyll-binding proteins (FCP). At the same time, an efficient adaptation of these complexes to fluctuating light conditions is necessary to protect the diatoms against photodamage. So far, structural and dynamic data for the interaction between FCP and the photoprotective LHCX family of proteins in diatoms are lacking. In this computational study, we provide a structural basis for a remarkable pH-dependent adaptation at the molecular level. Upon binding of the LHCX1 protein to the FCP complex together with a change in pH, conformational changes within the FCP protein result in a variation of the electronic coupling in a specific chlorophyll-fucoxanthin pair, leading to a change in the exciton transfer rate by almost an order of magnitude. A common strategy for photoprotection between diatoms and higher plants is identified and discussed.
Collapse
Affiliation(s)
- Anthi Chrysafoudi
- Department of Biology, University of Crete, Voutes University Campus, GR-70013 Heraklion, Crete, Greece
| | - Sayan Maity
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Vangelis Daskalakis
- Department of Chemical Engineering, Cyprus University of Technology, 30 Archbishop Kyprianou Str., 3603 Limassol, Cyprus
| |
Collapse
|
16
|
Brown M, Milligan A, Behrenfeld M. Photoacclimation State of Thalassiosira weissflogii is not Affected by Changes in Optical Depth Under A Fluctuating Light Regime Simulating Deep Mixing 1. JOURNAL OF PHYCOLOGY 2021; 57:1212-1222. [PMID: 33590492 DOI: 10.1111/jpy.13149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 01/26/2021] [Accepted: 01/28/2021] [Indexed: 05/25/2023]
Abstract
Satellite-based remote sensing allows for global estimates of phytoplankton primary productivity by converting measurements of ocean color or photon absorption into units of carbon fixation. Models which perform this conversion often require an estimate of phytoplankton photoacclimation state such as the carbon to chlorophyll a ratio (C:Chl). Recently, our group developed a new photoacclimation model that can be applied to models of primary production. The model assumes that the phytoplankton photoacclimation state is not affected by periods of darkness during deep mixing beneath the photic zone, due to reduction in the plastoquinone pool in darkness and the subsequent deactivation of the signal for chlorophyll synthesis. In this study, we tested these assumptions by culturing the marine diatom Thalassiosira weissflogii under fluctuating light conditions simulating three different optical depths with progressively increasing deep mixing periods. The photoacclimation state, measured by the ratio of C:Chl, in T. weissflogii was not affected by changes in the length of simulated deep mixing periods. In addition, analysis of photosynthesis vs. irradiance (PE) curves showed that increases in optical depth caused decreases in both the maximum Chl-normalized rate of photosynthesis (Pbmax ) and in the slope of light-limited photosynthesis (αb ), but had no effect on the half-saturation irradiance (Ek , another metric of photoacclimation). However, measurements of chlorophyll fluorescence during simulated deep mixing did not support the hypothesis that the PQ pool was reduced during dark periods. Thus, our findings support the use of the photoacclimation model for estimating primary production while suggesting the need for further research into the mechanisms controlling photoacclimation in the upper mixed layer environment of the ocean.
Collapse
Affiliation(s)
- Matthew Brown
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, 97331, USA
| | - Allen Milligan
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, 97331, USA
| | - Michael Behrenfeld
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, 97331, USA
| |
Collapse
|
17
|
Blommaert L, Chafai L, Bailleul B. The fine-tuning of NPQ in diatoms relies on the regulation of both xanthophyll cycle enzymes. Sci Rep 2021; 11:12750. [PMID: 34140542 PMCID: PMC8211711 DOI: 10.1038/s41598-021-91483-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 05/05/2021] [Indexed: 11/09/2022] Open
Abstract
Diatoms possess an efficient mechanism to dissipate photons as heat in conditions of excess light, which is visualized as the Non-Photochemical Quenching of chlorophyll a fluorescence (NPQ). In most diatom species, NPQ is proportional to the concentration of the xanthophyll cycle pigment diatoxanthin formed from diadinoxanthin by the diadinoxanthin de-epoxidase enzyme. The reverse reaction is performed by the diatoxanthin epoxidase. Despite the xanthophyll cycle's central role in photoprotection, its regulation is not yet well understood. The proportionality between diatoxanthin and NPQ allowed us to calculate the activity of both xanthophyll cycle enzymes in the model diatom Phaeodactylum tricornutum from NPQ kinetics. From there, we explored the light-dependency of the activity of both enzymes. Our results demonstrate that a tight regulation of both enzymes is key to fine-tune NPQ: (i) the rate constant of diadinoxanthin de-epoxidation is low under a light-limiting regime but increases as photosynthesis saturates, probably due to the thylakoidal proton gradient ΔpH (ii) the rate constant of diatoxanthin epoxidation exhibits an optimum under low light and decreases in the dark due to an insufficiency of the co-factor NADPH as well as in higher light through an as yet unresolved inhibition mechanism, that is unlikely to be related to the ΔpH. We observed that the suppression of NPQ by an uncoupler was due to an accelerated diatoxanthin epoxidation enzyme rather than to the usually hypothesized inhibition of the diadinoxanthin de-epoxidation enzyme.
Collapse
Affiliation(s)
- Lander Blommaert
- Laboratory of Chloroplast Biology and Light Sensing in Microalgae, UMR 7141, Centre National de La Recherche Scientifique (CNRS), Sorbonne Université, Institut de Biologie Physico-Chimique, 75005, Paris, France. .,Department of Estuarine and Delta System, NIOZ Royal Netherlands Institute for Sea Research, PO Box 140, 4400 AC, Yerseke, The Netherlands.
| | - Lamia Chafai
- Laboratory of Chloroplast Biology and Light Sensing in Microalgae, UMR 7141, Centre National de La Recherche Scientifique (CNRS), Sorbonne Université, Institut de Biologie Physico-Chimique, 75005, Paris, France
| | - Benjamin Bailleul
- Laboratory of Chloroplast Biology and Light Sensing in Microalgae, UMR 7141, Centre National de La Recherche Scientifique (CNRS), Sorbonne Université, Institut de Biologie Physico-Chimique, 75005, Paris, France.
| |
Collapse
|
18
|
Kayanja GE, Ibrahim IM, Puthiyaveetil S. Regulation of Phaeodactylum plastid gene transcription by redox, light, and circadian signals. PHOTOSYNTHESIS RESEARCH 2021; 147:317-328. [PMID: 33387192 DOI: 10.1007/s11120-020-00811-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/03/2020] [Indexed: 06/12/2023]
Abstract
Diatoms are a diverse group of photosynthetic unicellular algae with a plastid of red-algal origin. As prolific primary producers in the ocean, diatoms fix as much carbon as all rainforests combined. The molecular mechanisms that contribute to the high photosynthetic productivity and ecological success of diatoms are however not yet fully understood. Using the model diatom Phaeodactylum tricornutum, here we show rhythmic transcript accumulation of plastid psaA, psbA, petB, and atpB genes as driven by a free running circadian clock. Treatment with the electron transport inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea overrides the circadian signal by markedly downregulating transcription of psaA, petB, and atpB genes but not the psbA gene. Changes in light quantity produce little change in plastid gene transcription while the effect of light quality seems modest with only the psaA gene responding in a pattern that is dependent on the redox state of the plastoquinone pool. The significance of these plastid transcriptional responses and the identity of the underlying genetic control systems are discussed with relevance to diatom photosynthetic acclimation.
Collapse
Affiliation(s)
- Gilbert E Kayanja
- Department of Biochemistry and Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
| | - Iskander M Ibrahim
- Department of Biochemistry and Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
| | - Sujith Puthiyaveetil
- Department of Biochemistry and Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA.
| |
Collapse
|
19
|
Divergence of photosynthetic strategies amongst marine diatoms. PLoS One 2020; 15:e0244252. [PMID: 33370327 PMCID: PMC7769462 DOI: 10.1371/journal.pone.0244252] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/07/2020] [Indexed: 11/19/2022] Open
Abstract
Marine phytoplankton, and in particular diatoms, are responsible for almost half of all primary production on Earth. Diatom species thrive from polar to tropical waters and across light environments that are highly complex to relatively benign, and so have evolved highly divergent strategies for regulating light capture and utilization. It is increasingly well established that diatoms have achieved such successful ecosystem dominance by regulating excitation energy available for generating photosynthetic energy via highly flexible light harvesting strategies. However, how different light harvesting strategies and downstream pathways for oxygen production and consumption interact to balance excitation pressure remains unknown. We therefore examined the responses of three diatom taxa adapted to inherently different light climates (estuarine Thalassioisira weissflogii, coastal Thalassiosira pseudonana and oceanic Thalassiosira oceanica) during transient shifts from a moderate to high growth irradiance (85 to 1200 μmol photons m-2 s-1). Transient high light exposure caused T. weissflogii to rapidly downregulate PSII with substantial nonphotochemical quenching, protecting PSII from inactivation or damage, and obviating the need for induction of O2 consuming (light-dependent respiration, LDR) pathways. In contrast, T. oceanica retained high excitation pressure on PSII, but with little change in RCII photochemical turnover, thereby requiring moderate repair activity and greater reliance on LDR. T. pseudonana exhibited an intermediate response compared to the other two diatom species, exhibiting some downregulation and inactivation of PSII, but high repair of PSII and induction of reversible PSII nonphotochemical quenching, with some LDR. Together, these data demonstrate a range of strategies for balancing light harvesting and utilization across diatom species, which reflect their adaptation to sustain photosynthesis under environments with inherently different light regimes.
Collapse
|
20
|
Mann M, Serif M, Wrobel T, Eisenhut M, Madhuri S, Flachbart S, Weber APM, Lepetit B, Wilhelm C, Kroth PG. The Aureochrome Photoreceptor PtAUREO1a Is a Highly Effective Blue Light Switch in Diatoms. iScience 2020; 23:101730. [PMID: 33235981 PMCID: PMC7670200 DOI: 10.1016/j.isci.2020.101730] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/30/2020] [Accepted: 10/21/2020] [Indexed: 02/08/2023] Open
Abstract
Aureochromes represent a unique type of blue light photoreceptors that possess a blue light sensing flavin-binding LOV-domain and a DNA-binding bZIP domain, thus being light-driven transcription factors. The diatom Phaeodactylum tricornutum, a member of the essential marine primary producers, possesses four aureochromes (PtAUREO1a, 1b, 1c, 2). Here we show a dramatic change in the global gene expression pattern of P. tricornutum wild-type cells after a shift from red to blue light. About 75% of the genes show significantly changed transcript levels already after 10 and 60 min of blue light exposure, which includes genes of major transcription factors as well as other photoreceptors. Very surprisingly, this light-induced regulation of gene expression is almost completely inhibited in independent PtAureo1a knockout lines. Such a massive and fast transcriptional change depending on one single photoreceptor is so far unprecedented. We conclude that PtAUREO1a plays a key role in diatoms upon blue light exposure. Blue light induces a very fast transcriptional response in the diatom P. tricornutum This strong response is almost completely inhibited when Aureochrome 1a is absent The results imply a key role of PtAureo1a in blue light-induced responses in diatoms
Collapse
Affiliation(s)
- Marcus Mann
- Institut für Biologie, Universität Leipzig, 04009 Leipzig, Germany
| | - Manuel Serif
- Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany
| | - Thomas Wrobel
- Institut für Biochemie der Pflanzen, Cluster of Excellence on Plant Science (CEPLAS), Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Marion Eisenhut
- Institut für Biochemie der Pflanzen, Cluster of Excellence on Plant Science (CEPLAS), Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Shvaita Madhuri
- Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany
| | - Samantha Flachbart
- Institut für Biochemie der Pflanzen, Cluster of Excellence on Plant Science (CEPLAS), Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Andreas P M Weber
- Institut für Biochemie der Pflanzen, Cluster of Excellence on Plant Science (CEPLAS), Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
| | - Bernard Lepetit
- Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany
| | | | - Peter G Kroth
- Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany
| |
Collapse
|
21
|
Yoshida K, Seger A, Kennedy F, McMinn A, Suzuki K. Freezing, Melting, and Light Stress on the Photophysiology of Ice Algae: Ex Situ Incubation of the Ice Algal diatom Fragilariopsis cylindrus (Bacillariophyceae) Using an Ice Tank. JOURNAL OF PHYCOLOGY 2020; 56:1323-1338. [PMID: 32464687 DOI: 10.1111/jpy.13036] [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: 06/23/2019] [Accepted: 04/27/2020] [Indexed: 06/11/2023]
Abstract
Sea ice algae contribute up to 25% of the primary productivity of polar seas and seed large-scale ice-edge blooms. Fluctuations in temperature, salinity, and light associated with the freeze/thaw cycle can significantly impact the photophysiology of ice-associated taxa. The effects of multiple co-stressors (i.e., freezing temperature and high brine salinity or sudden high light exposure) on the photophysiology of ice algae were investigated in a series of ice tank experiments with the polar diatom Fragilariopsis cylindrus under different light intensities. When algal cells were frozen into the ice, the maximum quantum yield of photosystem II photochemistry (PSII; Fv /Fm ) decreased possibly due to the damage of PSII reaction centers and/or high brine salinity stress suppressing the reduction capacity downstream of PSII. Expression of the rbcL gene was highly up-regulated, suggesting that cells initiated strategies to enhance survival upon freezing in. Algae contained within the ice-matrix displayed similar levels of Fv /Fm regardless of the light treatments. Upon melting out, cells were exposed to high light (800 μmol photons · m-2 · s-1 ), resulting in a rapid decline in Fv /Fm and significant up-regulation of non-photochemical quenching (NPQ). These results suggest that ice algae employed safety valves (i.e., NPQ) to maintain their photosynthetic capability during the sudden environmental changes. Our results infer that sea ice algae are highly adaptable when exposed to multiple co-stressors and that their success can, in part, be explained by the ability to rapidly modify their photosynthetic competence - a key factor contributing to algal bloom formation in the polar seas.
Collapse
Affiliation(s)
- Kazuhiro Yoshida
- Graduate School of Environmental Science, Hokkaido University, North 10 West 5, Kita-Ku, Sapporo, 060-0810, Japan
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Hobart, TAS, 7004, Australia
| | - Andreas Seger
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Hobart, TAS, 7004, Australia
- South Australian Research and Development Institute, 2b Hartley Grove, Urrbrae, SA, 5064, Australia
| | - Fraser Kennedy
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Hobart, TAS, 7004, Australia
| | - Andrew McMinn
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Hobart, TAS, 7004, Australia
| | - Koji Suzuki
- Faculty of Environmental Earth Science, Hokkaido University, North 10 West 5, Kita-Ku, Sapporo, 060-0810, Japan
| |
Collapse
|
22
|
|
23
|
Kuczynska P, Jemiola-Rzeminska M, Nowicka B, Jakubowska A, Strzalka W, Burda K, Strzalka K. The xanthophyll cycle in diatom Phaeodactylum tricornutum in response to light stress. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 152:125-137. [PMID: 32416342 DOI: 10.1016/j.plaphy.2020.04.043] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 04/27/2020] [Accepted: 04/30/2020] [Indexed: 05/11/2023]
Abstract
Chosen aspects of the functioning of diadinoxanthin cycle in a model diatom Phaeodactylum tricornutum grown under low light conditions (LL) and under high light conditions (HL), which cause activation of violaxanthin cycle, were examined. Heterogeneity of the kinetics of diadinoxanthin ↔ diatoxanthin conversions regulated by de-epoxidase/epoxidase enzymes was detected. Three different rates of diadinoxanthin de-epoxidation (τ > 20 min, 5 min > τ > 1.5 min and τ ≤ 1 min) were observed. Appearance and contribution of these phases depended on the light conditions and xanthophylls subpopulations in membranes. Moreover, diadinoxanthin de-epoxidation was postulated to occur in darkness and its rate was estimated to be almost two times faster (τ ≈ 14 min) than diatoxanthin-epoxidation in LL- and HL-grown diatoms collected after the dark phase of the photoperiod and exposed to very high light and subsequent darkness. The level of lipid hydroperoxides and the expression of genes encoding xanthophyll cycle enzymes was measured. Our observations suggest that isoforms of these enzymes may participate in carotenoid synthesis or be exclusively involved in xanthophyll conversions. Violaxanthin cycle pigments present in HL-acclimated diatoms change thermodynamic properties of thylakoid membranes. Zeaxanthin is known to localize preferentially in the inner part of the lipid bilayer and diatoxanthin in its outer part. The different localization of these pigments probably decide about their complementary action in protection of the membranes against reactive oxygen species.
Collapse
Affiliation(s)
- Paulina Kuczynska
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland
| | - Malgorzata Jemiola-Rzeminska
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland; Malopolska Centre of Biotechnology, Jagiellonian University, Gronostajowa 7A, 30-387, Krakow, Poland
| | - Beatrycze Nowicka
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland.
| | - Agata Jakubowska
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland
| | - Wojciech Strzalka
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland
| | - Kvetoslava Burda
- Faculty of Physics and Applied Computer Science, University of Science and Technology, Reymonta 19, 30-059, Krakow, Poland
| | - Kazimierz Strzalka
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland; Malopolska Centre of Biotechnology, Jagiellonian University, Gronostajowa 7A, 30-387, Krakow, Poland
| |
Collapse
|
24
|
Goss R, Latowski D. Lipid Dependence of Xanthophyll Cycling in Higher Plants and Algae. FRONTIERS IN PLANT SCIENCE 2020; 11:455. [PMID: 32425962 PMCID: PMC7212465 DOI: 10.3389/fpls.2020.00455] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 03/27/2020] [Indexed: 05/11/2023]
Abstract
The xanthophyll cycles of higher plants and algae represent an important photoprotection mechanism. Two main xanthophyll cycles are known, the violaxanthin cycle of higher plants, green and brown algae and the diadinoxanthin cycle of Bacillariophyceae, Xanthophyceae, Haptophyceae, and Dinophyceae. The forward reaction of the xanthophyll cycles consists of the enzymatic de-epoxidation of violaxanthin to antheraxanthin and zeaxanthin or diadinoxanthin to diatoxanthin during periods of high light illumination. It is catalyzed by the enzymes violaxanthin or diadinoxanthin de-epoxidase. During low light or darkness the back reaction of the cycle, which is catalyzed by the enzymes zeaxanthin or diatoxanthin epoxidase, restores the epoxidized xanthophylls by a re-introduction of the epoxy groups. The de-epoxidation reaction takes place in the lipid phase of the thylakoid membrane and thus, depends on the nature, three dimensional structure and function of the thylakoid lipids. As the xanthophyll cycle pigments are usually associated with the photosynthetic light-harvesting proteins, structural re-arrangements of the proteins and changes in the protein-lipid interactions play an additional role for the operation of the xanthophyll cycles. In the present review we give an introduction to the lipid and fatty acid composition of thylakoid membranes of higher plants and algae. We introduce the readers to the reaction sequences, enzymes and function of the different xanthophyll cycles. The main focus of the review lies on the lipid dependence of xanthophyll cycling. We summarize the current knowledge about the role of lipids in the solubilization of xanthophyll cycle pigments. We address the importance of the three-dimensional lipid structures for the enzymatic xanthophyll conversion, with a special focus on non-bilayer lipid phases which are formed by the main thylakoid membrane lipid monogalactosyldiacylglycerol. We additionally describe how lipids and light-harvesting complexes interact in the thylakoid membrane and how these interactions can affect the structure of the thylakoids. In a dedicated chapter we offer a short overview of current membrane models, including the concept of membrane domains. We then use these concepts to present a model of the operative xanthophyll cycle as a transient thylakoid membrane domain which is formed during high light illumination of plants or algal cells.
Collapse
Affiliation(s)
- Reimund Goss
- Department of Plant Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
| | - Dariusz Latowski
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| |
Collapse
|
25
|
Lacour T, Babin M, Lavaud J. Diversity in Xanthophyll Cycle Pigments Content and Related Nonphotochemical Quenching (NPQ) Among Microalgae: Implications for Growth Strategy and Ecology. JOURNAL OF PHYCOLOGY 2020; 56:245-263. [PMID: 31674660 DOI: 10.1111/jpy.12944] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 10/04/2019] [Indexed: 05/12/2023]
Abstract
Xanthophyll cycle-related nonphotochemical quenching (NPQ), which is present in most photoautotrophs, allows dissipation of excess light energy. Xanthophyll cycle-related NPQ depends principally on xanthophyll cycle pigments composition and their effective involvement in NPQ. Xanthophyll cycle-related NPQ is tightly controlled by environmental conditions in a species-/strain-specific manner. These features are especially relevant in microalgae living in a complex and highly variable environment. The goal of this study was to perform a comparative assessment of NPQ ecophysiologies across microalgal taxa in order to underline the specific involvement of NPQ in growth adaptations and strategies. We used both published results and data acquired in our laboratory to understand the relationships between growth conditions (irradiance, temperature, and nutrient availability), xanthophyll cycle composition, and xanthophyll cycle pigments quenching efficiency in microalgae from various taxa. We found that in diadinoxanthin-containing species, the xanthophyll cycle pigment pool is controlled by energy pressure in all species. At any given energy pressure, however, the diatoxanthin content is higher in diatoms than in other diadinoxanthin-containing species. XC pigments quenching efficiency is species-specific and decreases with acclimation to higher irradiances. We found a clear link between the natural light environment of species/ecotypes and quenching efficiency amplitude. The presence of diatoxanthin or zeaxanthin at steady state in all species examined at moderate and high irradiances suggests that cells maintain a light-harvesting capacity in excess to cope with potential decrease in light intensity.
Collapse
Affiliation(s)
| | - Marcel Babin
- Takuvik Joint International Laboratory UMI3376, CNRS (France) & ULaval (Canada), Département de Biologie, Université Laval, Pavillon Alexandre-Vachon, 1045, Avenue de la Médecine, Québec, QC, G1V 0A6, Canada
| | - Johann Lavaud
- Takuvik Joint International Laboratory UMI3376, CNRS (France) & ULaval (Canada), Département de Biologie, Université Laval, Pavillon Alexandre-Vachon, 1045, Avenue de la Médecine, Québec, QC, G1V 0A6, Canada
| |
Collapse
|
26
|
Falciatore A, Jaubert M, Bouly JP, Bailleul B, Mock T. Diatom Molecular Research Comes of Age: Model Species for Studying Phytoplankton Biology and Diversity. THE PLANT CELL 2020; 32:547-572. [PMID: 31852772 PMCID: PMC7054031 DOI: 10.1105/tpc.19.00158] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 10/18/2019] [Accepted: 12/13/2019] [Indexed: 05/08/2023]
Abstract
Diatoms are the world's most diverse group of algae, comprising at least 100,000 species. Contributing ∼20% of annual global carbon fixation, they underpin major aquatic food webs and drive global biogeochemical cycles. Over the past two decades, Thalassiosira pseudonana and Phaeodactylum tricornutum have become the most important model systems for diatom molecular research, ranging from cell biology to ecophysiology, due to their rapid growth rates, small genomes, and the cumulative wealth of associated genetic resources. To explore the evolutionary divergence of diatoms, additional model species are emerging, such as Fragilariopsis cylindrus and Pseudo-nitzschia multistriata Here, we describe how functional genomics and reverse genetics have contributed to our understanding of this important class of microalgae in the context of evolution, cell biology, and metabolic adaptations. Our review will also highlight promising areas of investigation into the diversity of these photosynthetic organisms, including the discovery of new molecular pathways governing the life of secondary plastid-bearing organisms in aquatic environments.
Collapse
Affiliation(s)
- Angela Falciatore
- Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light Sensing in Microalgae, UMR7141 Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, 75005 Paris, France
- Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, UMR7238 Sorbonne Université, 75005 Paris, France
| | - Marianne Jaubert
- Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light Sensing in Microalgae, UMR7141 Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, 75005 Paris, France
- Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, UMR7238 Sorbonne Université, 75005 Paris, France
| | - Jean-Pierre Bouly
- Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light Sensing in Microalgae, UMR7141 Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, 75005 Paris, France
- Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, UMR7238 Sorbonne Université, 75005 Paris, France
| | - Benjamin Bailleul
- Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light Sensing in Microalgae, UMR7141 Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, 75005 Paris, France
| | - Thomas Mock
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| |
Collapse
|
27
|
Dautermann O, Lyska D, Andersen-Ranberg J, Becker M, Fröhlich-Nowoisky J, Gartmann H, Krämer LC, Mayr K, Pieper D, Rij LM, Wipf HML, Niyogi KK, Lohr M. An algal enzyme required for biosynthesis of the most abundant marine carotenoids. SCIENCE ADVANCES 2020; 6:eaaw9183. [PMID: 32181334 PMCID: PMC7056318 DOI: 10.1126/sciadv.aaw9183] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 12/11/2019] [Indexed: 05/04/2023]
Abstract
Fucoxanthin and its derivatives are the main light-harvesting pigments in the photosynthetic apparatus of many chromalveolate algae and represent the most abundant carotenoids in the world's oceans, thus being major facilitators of marine primary production. A central step in fucoxanthin biosynthesis that has been elusive so far is the conversion of violaxanthin to neoxanthin. Here, we show that in chromalveolates, this reaction is catalyzed by violaxanthin de-epoxidase-like (VDL) proteins and that VDL is also involved in the formation of other light-harvesting carotenoids such as peridinin or vaucheriaxanthin. VDL is closely related to the photoprotective enzyme violaxanthin de-epoxidase that operates in plants and most algae, revealing that in major phyla of marine algae, an ancient gene duplication triggered the evolution of carotenoid functions beyond photoprotection toward light harvesting.
Collapse
Affiliation(s)
- O. Dautermann
- Institut für Molekulare Physiologie, Pflanzenbiochemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - D. Lyska
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - J. Andersen-Ranberg
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - M. Becker
- Institut für Molekulare Physiologie, Pflanzenbiochemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - J. Fröhlich-Nowoisky
- Institut für Molekulare Physiologie, Pflanzenbiochemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - H. Gartmann
- Institut für Molekulare Physiologie, Pflanzenbiochemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - L. C. Krämer
- Institut für Molekulare Physiologie, Pflanzenbiochemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - K. Mayr
- Institut für Molekulare Physiologie, Pflanzenbiochemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - D. Pieper
- Institut für Molekulare Physiologie, Pflanzenbiochemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - L. M. Rij
- Institut für Molekulare Physiologie, Pflanzenbiochemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - H. M.-L. Wipf
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - K. K. Niyogi
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - M. Lohr
- Institut für Molekulare Physiologie, Pflanzenbiochemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| |
Collapse
|
28
|
Complete genome sequence of Dyadobacter sp. 32, isolated from a culture of the freshwater diatom Cymbella microcephala. Mar Genomics 2019; 52:100720. [PMID: 31704048 DOI: 10.1016/j.margen.2019.100720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/25/2019] [Accepted: 10/18/2019] [Indexed: 11/22/2022]
Abstract
Bacteria have been shown to be involved in different species-specific interactions with eukaryotic algae such as diatoms, impacting important ecosystem processes. Recently, a strain assigned to Dyadobacter, named 'species 32', has been shown to be involved in a number of ecologically relevant diatom processes, such as biofilm formation or growth enhancement, depending on the diatom species. This bacterium was originally isolated from a culture of freshwater benthic diatoms that originated from an epilithic biofilm, in which both bacteria and diatoms coexist. A single complete circular chromosome of Dyadobacter sp. 32 was assembled with a length of 7,101,228 bp, containing 6062 protein coding genes and 3 rRNA operons. A number of interesting genetic features were found, such as a putative zeaxanthin biosynthetic gene cluster. A large number of polysaccharide utilizing gene clusters were also detected, along with genes potentially acquired from other bacteria through horizontal gene transfer, and genes previously identified in other algae-bacteria interactions. These data serve to increase our understanding of specific interactions within freshwater biofilms, and identify a number of gene targets with which to study the molecular basis of diatom-bacteria interactions.
Collapse
|
29
|
Nymark M, Volpe C, Hafskjold MCG, Kirst H, Serif M, Vadstein O, Bones AM, Melis A, Winge P. Loss of ALBINO3b Insertase Results in Truncated Light-Harvesting Antenna in Diatoms. PLANT PHYSIOLOGY 2019; 181:1257-1276. [PMID: 31467163 PMCID: PMC6836812 DOI: 10.1104/pp.19.00868] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 08/10/2019] [Indexed: 05/13/2023]
Abstract
The family of chloroplast ALBINO3 (ALB3) proteins function in the insertion and assembly of thylakoid membrane protein complexes. Loss of ALB3b in the marine diatom Phaeodactylum tricornutum leads to a striking change of cell color from the normal brown to green. A 75% decrease of the main fucoxanthin-chlorophyll a/c-binding proteins was identified in the alb3b strains as the cause of changes in the spectral properties of the mutant cells. The alb3b lines exhibit a truncated light-harvesting antenna phenotype with reduced amounts of light-harvesting pigments and require a higher light intensity for saturation of photosynthesis. Accumulation of photoprotective pigments and light-harvesting complex stress-related proteins was not negatively affected in the mutant strains, but still the capacity for nonphotochemical quenching was lower compared with the wild type. In plants and green algae, ALB3 proteins interact with members of the chloroplast signal recognition particle pathway through a Lys-rich C-terminal domain. A novel conserved C-terminal domain was identified in diatoms and other stramenopiles, questioning if ALB3b proteins have the same interaction partners as their plant/green algae homologs.
Collapse
Affiliation(s)
- Marianne Nymark
- Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - Charlotte Volpe
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | | | - Henning Kirst
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720
| | - Manuel Serif
- Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - Olav Vadstein
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - Atle Magnar Bones
- Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - Anastasios Melis
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720
| | - Per Winge
- Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| |
Collapse
|
30
|
Buck JM, Sherman J, Bártulos CR, Serif M, Halder M, Henkel J, Falciatore A, Lavaud J, Gorbunov MY, Kroth PG, Falkowski PG, Lepetit B. Lhcx proteins provide photoprotection via thermal dissipation of absorbed light in the diatom Phaeodactylum tricornutum. Nat Commun 2019; 10:4167. [PMID: 31519883 PMCID: PMC6744471 DOI: 10.1038/s41467-019-12043-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 08/16/2019] [Indexed: 11/15/2022] Open
Abstract
Diatoms possess an impressive capacity for rapidly inducible thermal dissipation of excess absorbed energy (qE), provided by the xanthophyll diatoxanthin and Lhcx proteins. By knocking out the Lhcx1 and Lhcx2 genes individually in Phaeodactylum tricornutum strain 4 and complementing the knockout lines with different Lhcx proteins, multiple mutants with varying qE capacities are obtained, ranging from zero to high values. We demonstrate that qE is entirely dependent on the concerted action of diatoxanthin and Lhcx proteins, with Lhcx1, Lhcx2 and Lhcx3 having similar functions. Moreover, we establish a clear link between Lhcx1/2/3 mediated inducible thermal energy dissipation and a reduction in the functional absorption cross-section of photosystem II. This regulation of the functional absorption cross-section can be tuned by altered Lhcx protein expression in response to environmental conditions. Our results provide a holistic understanding of the rapidly inducible thermal energy dissipation process and its mechanistic implications in diatoms. Photosynthetic organisms can dissipate excess absorbed light energy as heat to avoid photodamage. Here the authors show that induced thermal dissipation in the diatom Phaeodactylum tricornutum Pt4 is Lhcx protein-dependent and correlates with a reduced functional absorption cross-section of photosystem II.
Collapse
Affiliation(s)
- Jochen M Buck
- Plant Ecophysiology, Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Jonathan Sherman
- Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Carolina Río Bártulos
- Plant Ecophysiology, Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Manuel Serif
- Plant Ecophysiology, Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Marc Halder
- Plant Ecophysiology, Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Jan Henkel
- Plant Ecophysiology, Department of Biology, University of Konstanz, 78457, Konstanz, Germany.,Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland
| | - Angela Falciatore
- Sorbonne Université, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, F-75005, Paris, France
| | - Johann Lavaud
- UMI 3376 Takuvik, CNRS/ULaval, Département de Biologie, Pavillon Alexandre-Vachon, Université Laval, Québec (Québec), G1V 0A6, Canada
| | - Maxim Y Gorbunov
- Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Peter G Kroth
- Plant Ecophysiology, Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Paul G Falkowski
- Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Bernard Lepetit
- Plant Ecophysiology, Department of Biology, University of Konstanz, 78457, Konstanz, Germany. .,Zukunftskolleg, University of Konstanz, 78457, Konstanz, Germany.
| |
Collapse
|
31
|
Metabolic Innovations Underpinning the Origin and Diversification of the Diatom Chloroplast. Biomolecules 2019; 9:biom9080322. [PMID: 31366180 PMCID: PMC6723447 DOI: 10.3390/biom9080322] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 07/24/2019] [Accepted: 07/25/2019] [Indexed: 12/13/2022] Open
Abstract
Of all the eukaryotic algal groups, diatoms make the most substantial contributions to photosynthesis in the contemporary ocean. Understanding the biological innovations that have occurred in the diatom chloroplast may provide us with explanations to the ecological success of this lineage and clues as to how best to exploit the biology of these organisms for biotechnology. In this paper, we use multi-species transcriptome datasets to compare chloroplast metabolism pathways in diatoms to other algal lineages. We identify possible diatom-specific innovations in chloroplast metabolism, including the completion of tocopherol synthesis via a chloroplast-targeted tocopherol cyclase, a complete chloroplast ornithine cycle, and chloroplast-targeted proteins involved in iron acquisition and CO2 concentration not shared between diatoms and their closest relatives in the stramenopiles. We additionally present a detailed investigation of the chloroplast metabolism of the oil-producing diatom Fistulifera solaris, which is of industrial interest for biofuel production. These include modified amino acid and pyruvate hub metabolism that might enhance acetyl-coA production for chloroplast lipid biosynthesis and the presence of a chloroplast-localised squalene synthesis pathway unknown in other diatoms. Our data provides valuable insights into the biological adaptations underpinning an ecologically critical lineage, and how chloroplast metabolism can change even at a species level in extant algae.
Collapse
|
32
|
Mizrachi A, Graff van Creveld S, Shapiro OH, Rosenwasser S, Vardi A. Light-dependent single-cell heterogeneity in the chloroplast redox state regulates cell fate in a marine diatom. eLife 2019; 8:47732. [PMID: 31232691 PMCID: PMC6682412 DOI: 10.7554/elife.47732] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 06/18/2019] [Indexed: 12/14/2022] Open
Abstract
Diatoms are photosynthetic microorganisms of great ecological and biogeochemical importance, forming vast blooms in aquatic ecosystems. However, we are still lacking fundamental understanding of how individual cells sense and respond to diverse stress conditions, and what acclimation strategies are employed during bloom dynamics. We investigated cellular responses to environmental stress at the single-cell level using the redox sensor roGFP targeted to various organelles in the diatom Phaeodactylum tricornutum. We detected cell-to-cell variability using flow cytometry cell sorting and a microfluidics system for live imaging of oxidation dynamics. Chloroplast-targeted roGFP exhibited a light-dependent, bi-stable oxidation pattern in response to H2O2 and high light, revealing distinct subpopulations of sensitive oxidized cells and resilient reduced cells. Early oxidation in the chloroplast preceded commitment to cell death, and can be used for sensing stress cues and regulating cell fate. We propose that light-dependent metabolic heterogeneity regulates diatoms’ sensitivity to environmental stressors in the ocean. Microscopic algae, such as diatoms, are widely spread throughout the oceans, and are responsible for half of the oxygen we breathe. At certain times of the year these algae grow very rapidly to form large “blooms” that can be detected by satellites in space. These blooms are generally short-lived because the algae are either eaten by other marine organisms, run out of nutrients, or die as a result of being infected by viruses or bacteria. However, some diatom cells survive the end of the bloom and go on to generate new blooms in the future, but it is still not clear how. As the bloom collapses, diatoms experience many stressful conditions which can cause active molecules known as reactive oxygen species, or ROS for short, to accumulate inside cells. Normally growing cells also produce low amounts of ROS, which regulate various processes that are important for maintaining a cell’s health. However, high amounts of ROS can cause damage, which may lead to a cell’s death. Now, Mizrachi et al. investigated why some algae survive while others die in response to stressful conditions, focusing on the amount of ROS that accumulates within the diatom Phaeodactylum tricornutum. Laboratory experiments showed that individual cells of P. tricornutum respond differently to environmental stress, forming two distinct groups of either sensitive or resilient cells. Sensitive cells accumulated high levels of ROS within a cell compartment known as the chloroplast and eventually died. Whereas resilient cells were able to maintain low levels of ROS in the chloroplast and survived long after the other cells perished. Populations of genetically identical diatom cells also formed distinct groups of sensitive and resilient cells, demonstrating that these two opposing reactions to stress are not caused by genetic differences between cells. Lastly, Mizrachi et al. showed that how diatoms acclimate to stress depends on the amount of light they are exposed to. When in the dark, all cells became sensitive to oxidative stress, without forming distinct groups. But, when exposed to strong light that mimics the ocean surface, cells formed distinct groups within the population. This suggests that light regulates how susceptible these microscopic algae are to environmental stress. The different responses within a population may serve as a “bet-hedging” strategy, enabling at least some of the cells to survive unpredicted stressful conditions. The next challenge will be to find out whether algae growing in the oceans also use the same strategy and investigate what impact this has on diatom blooms.
Collapse
Affiliation(s)
- Avia Mizrachi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Shiri Graff van Creveld
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Orr H Shapiro
- Department of Food Quality and Safety, Institute of Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion, Israel
| | - Shilo Rosenwasser
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel.,The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Assaf Vardi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| |
Collapse
|
33
|
Büchel C. Light harvesting complexes in chlorophyll c-containing algae. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1861:148027. [PMID: 31153887 DOI: 10.1016/j.bbabio.2019.05.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/22/2019] [Accepted: 05/24/2019] [Indexed: 12/30/2022]
Abstract
Besides the so-called 'green lineage' of eukaryotic photosynthetic organisms that include vascular plants, a huge variety of different algal groups exist that also harvest light by means of membrane intrinsic light harvesting proteins (Lhc). The main taxa of these algae are the Cryptophytes, Haptophytes, Dinophytes, Chromeridae and the Heterokonts, the latter including diatoms, brown algae, Xanthophyceae and Eustigmatophyceae amongst others. Despite the similarity in Lhc proteins between vascular plants and these algae, pigmentation is significantly different since no Chl b is bound, but often replaced by Chl c, and a large diversity in carotenoids functioning in light harvesting and/or photoprotection is present. Due to the presence of Chl c in most of the taxa the name 'Chl c-containing organisms' has become common, however, Chl b-less is more precise since some harbour Lhc proteins that only bind one type of Chl, Chl a. In recent years huge progress has been made about the occurrence and function of Lhc in diatoms, so-called fucoxanthin chlorophyll proteins (FCP), where also the first molecular structure became available recently. In addition, especially energy transfer amongst the unusual pigments bound was intensively studied in many of these groups. This review summarises the present knowledge about the molecular structure, the arrangement of the different Lhc in complexes, the excitation energy transfer abilities and the involvement in photoprotection of the different Lhc systems in the so-called Chl c-containing organisms. This article is part of a Special Issue entitled Light harvesting, edited by Dr. Roberta Croce.
Collapse
Affiliation(s)
- Claudia Büchel
- Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt, Germany.
| |
Collapse
|
34
|
Vetoshkina DV, Pozdnyakova-Filatova IY, Zhurikova EM, Frolova AA, Naydov IA, Ivanov BN, Borisova-Mubarakshina MM. The Increase in Adaptive Capacity to High Illumination of Barley Plants Colonized by Rhizobacteria P. putida BS3701. APPL BIOCHEM MICRO+ 2019. [DOI: 10.1134/s0003683819020133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
35
|
Gundermann K, Wagner V, Mittag M, Büchel C. Fucoxanthin-Chlorophyll Protein Complexes of the Centric Diatom Cyclotella Meneghiniana Differ in Lhcx1 and Lhcx6_1 Content. PLANT PHYSIOLOGY 2019; 179:1779-1795. [PMID: 30733257 PMCID: PMC6446762 DOI: 10.1104/pp.18.01363] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 01/30/2019] [Indexed: 05/19/2023]
Abstract
The ecological success of diatoms, key contributors to photosynthesis, is partly based on their ability to perfectly balance efficient light harvesting and photoprotection. Diatoms contain higher numbers of antenna proteins than vascular plants for light harvesting and for photoprotection. These proteins are arranged in fucoxanthin-chlorophyll protein (FCP) complexes. The number of FCP complexes, their subunit composition, and their interactions in the thylakoid membranes remain elusive in different diatoms. We used the recently available genome sequence of the centric diatom Cyclotella cryptica to analyze gene sequences for putative light-harvesting proteins in C. meneghiniana, and to elucidate the FCP complex composition. We analyzed two pools of FCP complexes that were trimeric (FCPa) and nonameric (FCPb). FCPa was composed of four different trimeric subtypes. Two different nonameric FCPb complexes were present. All were distinguished by their polypeptide composition and partly by pigmentation. With use of a milder purification method, two fractions composed of different FCP complexes were isolated. One was enriched in FCPs incorporating the photoprotective subunit Lhcx1, such as the newly identified nonameric FCPb2 and the major trimeric FCPa4 complex, which are predetermined to be involved in energy-dependent nonphotochemical quenching. The other fraction contained mainly FCPs that were devoid of Lhcx1, FCPa3, and FCPb1. Both fractions also included small amounts of trimeric FCPa complexes with the centric diatom-specific Lhcx protein, Lhcx6_1, as subunit. Thus, the antenna organization of centric diatoms, as well as the distribution of different photoprotective Lhcx proteins, differs from that of other diatoms, as well as from plants.
Collapse
Affiliation(s)
- Kathi Gundermann
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt, Germany
| | - Volker Wagner
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University, 07743 Jena, Germany
| | - Maria Mittag
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University, 07743 Jena, Germany
| | - Claudia Büchel
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt, Germany
| |
Collapse
|
36
|
Baldisserotto C, Sabia A, Ferroni L, Pancaldi S. Biological aspects and biotechnological potential of marine diatoms in relation to different light regimens. World J Microbiol Biotechnol 2019; 35:35. [PMID: 30712106 DOI: 10.1007/s11274-019-2607-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 01/27/2019] [Indexed: 11/25/2022]
Abstract
As major primary producers in marine environments, diatoms are considered a valuable feedstock of biologically active compounds for application in several biotechnological fields. Due to their metabolic plasticity, especially for light perception and use and in order to make microalgal production more environmentally sustainable, marine diatoms are considered good candidates for the large-scale cultivation. Among physical parameters, light plays a primary role. Even if sunlight is cost-effective, the employment of artificial light becomes a winning strategy if a high-value microalgal biomass is produced. Several researches on marine diatoms are designed to study the influence of different light regimens to increase biomass production enriched in biotechnologically high-value compounds (lipids, carotenoids, proteins, polysaccharides), or with emphasised photonic properties of the frustule.
Collapse
Affiliation(s)
- Costanza Baldisserotto
- Department of Life Sciences and Biotechnology, University of Ferrara, C.so Ercole I d'Este, 32, 44121, Ferrara, Italy
| | - Alessandra Sabia
- Department of Life Sciences and Biotechnology, University of Ferrara, C.so Ercole I d'Este, 32, 44121, Ferrara, Italy
| | - Lorenzo Ferroni
- Department of Life Sciences and Biotechnology, University of Ferrara, C.so Ercole I d'Este, 32, 44121, Ferrara, Italy
| | - Simonetta Pancaldi
- Department of Life Sciences and Biotechnology, University of Ferrara, C.so Ercole I d'Este, 32, 44121, Ferrara, Italy.
| |
Collapse
|
37
|
Unique photosynthetic electron transport tuning and excitation distribution in heterokont algae. PLoS One 2019; 14:e0209920. [PMID: 30625205 PMCID: PMC6326504 DOI: 10.1371/journal.pone.0209920] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 12/13/2018] [Indexed: 01/01/2023] Open
Abstract
Heterokont algae are significant contributors to marine primary productivity. These algae have a photosynthetic machinery that shares many common features with that of Viridiplantae (green algae and land plants). Here we demonstrate, however, that the photosynthetic machinery of heterokont algae responds to light fundamentally differently than that of Viridiplantae. While exposure to high light leads to electron accumulation within the photosynthetic electron transport chain in Viridiplantae, this is not the case in heterokont algae. We use this insight to manipulate the photosynthetic electron transport chain and demonstrate that heterokont algae can dynamically distribute excitation energy between the two types of photosystems. We suggest that the reported electron transport and excitation distribution features are adaptations to the marine light environment.
Collapse
|
38
|
Stamatakis K, Broussos PI, Panagiotopoulou A, Gast RJ, Pelecanou M, Papageorgiou GC. Light-adaptive state transitions in the Ross Sea haptophyte Phaeocystis antarctica and in dinoflagellate cells hosting kleptoplasts derived from it. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1860:102-110. [PMID: 30414926 DOI: 10.1016/j.bbabio.2018.11.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 09/11/2018] [Accepted: 11/07/2018] [Indexed: 11/19/2022]
Abstract
Light state transitions (STs) is a reversible physiological process that oxygenic photosynthetic organisms use in order to minimize imbalances in the electronic excitation delivery to the reaction centers of Photosystems I and II, and thus to optimize photosynthesis. STs have been studied extensively in plants, green algae, red algae and cyanobacteria, but sparsely in algae with secondary red algal plastids, such as diatoms and haptophytes, despite their immense ecological significance. In the present work, we examine whether the haptophyte alga Phaeocystis antarctica, and dinoflagellate cells that host kleptoplasts derived from P. antarctica, both endemic in the Ross Sea, Antarctica, are capable of light adaptive STs. In these organisms, Chl a fluorescence can be excited either by direct light absorption, or indirectly by electronic excitation (EE) transfer from ultraviolet light absorbing mycosporine-like amino acids (MAAs) to Chl a (Stamatakis et al., Biochim. Biophys. Acta 1858 [2017] 189-195). Here we show that, on adaptation to PS II-selective light, dark-adapted P. antarctica cells shift from light state 1 (ST1; more EE ending up in PS II) to light state 2 (ST2; more EE ending up in PS I), as revealed by the spectral distribution of directly-excited Chl a fluorescence and by changes in the macro-organization of pigment-protein complexes evidenced by circular dichroism (CD) spectroscopy. In contrast, no STs are clearly detected in the case of the kleptoplast-hosting dinoflagellate cells, and in the case of indirectly excited Chls a, via MAAs, in P. antarctica cells.
Collapse
Affiliation(s)
- Kostas Stamatakis
- Institute of Biosciences and Applications, NCSR "Demokritos", 15310, Aghia Paraskevi Attikis, Greece.
| | - Panayiotis-Ilias Broussos
- Institute of Biosciences and Applications, NCSR "Demokritos", 15310, Aghia Paraskevi Attikis, Greece
| | - Angeliki Panagiotopoulou
- Institute of Biosciences and Applications, NCSR "Demokritos", 15310, Aghia Paraskevi Attikis, Greece
| | - Rebecca J Gast
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Maria Pelecanou
- Institute of Biosciences and Applications, NCSR "Demokritos", 15310, Aghia Paraskevi Attikis, Greece
| | - George C Papageorgiou
- Institute of Biosciences and Applications, NCSR "Demokritos", 15310, Aghia Paraskevi Attikis, Greece
| |
Collapse
|
39
|
Hao TB, Jiang T, Dong HP, Ou LJ, He X, Yang YF. Light-harvesting protein Lhcx3 is essential for high light acclimation of Phaeodactylum tricornutum. AMB Express 2018; 8:174. [PMID: 30353255 PMCID: PMC6199207 DOI: 10.1186/s13568-018-0703-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 10/19/2018] [Indexed: 12/21/2022] Open
Abstract
The light-harvesting protein complexes (Lhc) play key roles in the processes of light absorption and protection in diatoms. However, different Lhc protein carries out distinct function in photosynthesis. For now, roles of many Lhc proteins in light acclimation are largely unknown. Here, function of Lhcx3 in marine diatom Phaeodactylum tricornutum was examined by using reverse genetic technologies. The overexpression of Lhcx3 led to increased diadinoxanthin + diatoxanthin content and elevated non-photochemical fluorescence quenching (NPQ) while knockdown of Lhcx3 reduced NPQ level. In addition, the expression of Lhcx3 could be induced by blue light but not by red light. After addition of the photosynthetic inhibitor, upregulation of Lhcx3 transcript in high light could be inhibited by NH4Cl, but not by DCMU (3-(3,4-dichlorophenyl)-l,l-dim ethylurea). In contrast, DCMU addition increased expression of Lhcx3 in high light. In combination with changes of NPQ after addition of inhibitor, we concluded that the Lhcx3 played key roles in high light acclimation of diatoms. This finding will provide new clues for genetic improvement of P. tricornutum with an aim to cultivate new strains with high growth rate.
Collapse
|
40
|
Yang M, Lin X, Liu X, Zhang J, Ge F. Genome Annotation of a Model Diatom Phaeodactylum tricornutum Using an Integrated Proteogenomic Pipeline. MOLECULAR PLANT 2018; 11:1292-1307. [PMID: 30176371 DOI: 10.1016/j.molp.2018.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/26/2018] [Accepted: 08/28/2018] [Indexed: 06/08/2023]
Abstract
Diatoms comprise a diverse and ecologically important group of eukaryotic phytoplankton that significantly contributes to marine primary production and global carbon cycling. Phaeodactylum tricornutum is commonly used as a model organism for studying diatom biology. Although its genome was sequenced in 2008, a high-quality genome annotation is still not available for this diatom. Here we report the development of an integrated proteogenomic pipeline and its application for improved annotation of P. tricornutum genome using mass spectrometry (MS)-based proteomics data. Our proteogenomic analysis unambiguously identified approximately 8300 genes and revealed 606 novel proteins, 506 revised genes, 94 splice variants, 58 single amino acid variants, and a holistic view of post-translational modifications in P. tricornutum. We experimentally confirmed a subset of novel events and obtained MS evidence for more than 200 micropeptides in P. tricornutum. These findings expand the genomic landscape of P. tricornutum and provide a rich resource for the study of diatom biology. The proteogenomic pipeline we developed in this study is applicable to any sequenced eukaryote and thus represents a significant contribution to the toolset for eukaryotic proteogenomic analysis. The pipeline and its source code are freely available at https://sourceforge.net/projects/gapeproteogenomic.
Collapse
Affiliation(s)
- Mingkun Yang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Xiaohuang Lin
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100039, China
| | - Xin Liu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100039, China
| | - Jia Zhang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Feng Ge
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100039, China.
| |
Collapse
|
41
|
Kroth PG, Bones AM, Daboussi F, Ferrante MI, Jaubert M, Kolot M, Nymark M, Río Bártulos C, Ritter A, Russo MT, Serif M, Winge P, Falciatore A. Genome editing in diatoms: achievements and goals. PLANT CELL REPORTS 2018; 37:1401-1408. [PMID: 30167805 DOI: 10.1007/s00299-018-2334-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 08/07/2018] [Indexed: 05/20/2023]
Abstract
Diatoms are major components of phytoplankton and play a key role in the ecology of aquatic ecosystems. These algae are of great scientific importance for a wide variety of research areas, ranging from marine ecology and oceanography to biotechnology. During the last 20 years, the availability of genomic information on selected diatom species and a substantial progress in genetic manipulation, strongly contributed to establishing diatoms as molecular model organisms for marine biology research. Recently, tailored TALEN endonucleases and the CRISPR/Cas9 system were utilized in diatoms, allowing targeted genetic modifications and the generation of knockout strains. These approaches are extremely valuable for diatom research because breeding, forward genetic screens by random insertion, and chemical mutagenesis are not applicable to the available model species Phaeodactylum tricornutum and Thalassiosira pseudonana, which do not cross sexually in the lab. Here, we provide an overview of the genetic toolbox that is currently available for performing stable genetic modifications in diatoms. We also discuss novel challenges that need to be addressed to fully exploit the potential of these technologies for the characterization of diatom biology and for metabolic engineering.
Collapse
Affiliation(s)
- Peter G Kroth
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany.
| | - Atle M Bones
- Cell, Molecular Biology and Genomics Group, Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Fayza Daboussi
- LISBP, Université de Toulouse, CNRS, INSA, 135 Avenue de Rangueil, 31077, Toulouse, France
| | - Maria I Ferrante
- Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, Villa Comunale 1, Naples, 80121, Italy
| | - Marianne Jaubert
- Laboratoire de Biologie Computationnelle et Quantitative, Institut de Biologie Paris-Seine, Sorbonne Université, CNRS, 75005, Paris, France
| | - Misha Kolot
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 76100, Rehovot, Israel
- Department of Biochemistry and Molecular Biology, Tel-Aviv University, Tel-Aviv, 69978, Israel
| | - Marianne Nymark
- Cell, Molecular Biology and Genomics Group, Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | | | - Andrés Ritter
- Laboratoire de Biologie Computationnelle et Quantitative, Institut de Biologie Paris-Seine, Sorbonne Université, CNRS, 75005, Paris, France
| | - Monia T Russo
- Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, Villa Comunale 1, Naples, 80121, Italy
| | - Manuel Serif
- LISBP, Université de Toulouse, CNRS, INSA, 135 Avenue de Rangueil, 31077, Toulouse, France
| | - Per Winge
- Cell, Molecular Biology and Genomics Group, Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Angela Falciatore
- Laboratoire de Biologie Computationnelle et Quantitative, Institut de Biologie Paris-Seine, Sorbonne Université, CNRS, 75005, Paris, France.
| |
Collapse
|
42
|
The evolution of the photoprotective antenna proteins in oxygenic photosynthetic eukaryotes. Biochem Soc Trans 2018; 46:1263-1277. [DOI: 10.1042/bst20170304] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 07/02/2018] [Accepted: 07/04/2018] [Indexed: 12/24/2022]
Abstract
Photosynthetic organisms require rapid and reversible down-regulation of light harvesting to avoid photodamage. Response to unpredictable light fluctuations is achieved by inducing energy-dependent quenching, qE, which is the major component of the process known as non-photochemical quenching (NPQ) of chlorophyll fluorescence. qE is controlled by the operation of the xanthophyll cycle and accumulation of specific types of proteins, upon thylakoid lumen acidification. The protein cofactors so far identified to modulate qE in photosynthetic eukaryotes are the photosystem II subunit S (PsbS) and light-harvesting complex stress-related (LHCSR/LHCX) proteins. A transition from LHCSR- to PsbS-dependent qE took place during the evolution of the Viridiplantae (also known as ‘green lineage’ organisms), such as green algae, mosses and vascular plants. Multiple studies showed that LHCSR and PsbS proteins have distinct functions in the mechanism of qE. LHCX(-like) proteins are closely related to LHCSR proteins and found in ‘red lineage’ organisms that contain secondary red plastids, such as diatoms. Although LHCX proteins appear to control qE in diatoms, their role in the mechanism remains poorly understood. Here, we present the current knowledge on the functions and evolution of these crucial proteins, which evolved in photosynthetic eukaryotes to optimise light harvesting.
Collapse
|
43
|
Taddei L, Chukhutsina VU, Lepetit B, Stella GR, Bassi R, van Amerongen H, Bouly JP, Jaubert M, Finazzi G, Falciatore A. Dynamic Changes between Two LHCX-Related Energy Quenching Sites Control Diatom Photoacclimation. PLANT PHYSIOLOGY 2018; 177:953-965. [PMID: 29773581 PMCID: PMC6053010 DOI: 10.1104/pp.18.00448] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 05/04/2018] [Indexed: 05/20/2023]
Abstract
Marine diatoms are prominent phytoplankton organisms that perform photosynthesis in extremely variable environments. Diatoms possess a strong ability to dissipate excess absorbed energy as heat via nonphotochemical quenching (NPQ). This process relies on changes in carotenoid pigment composition (xanthophyll cycle) and on specific members of the light-harvesting complex family specialized in photoprotection (LHCXs), which potentially act as NPQ effectors. However, the link between light stress, NPQ, and the existence of different LHCX isoforms is not understood in these organisms. Using picosecond fluorescence analysis, we observed two types of NPQ in the pennate diatom Phaeodactylum tricornutum that were dependent on light conditions. Short exposure of low-light-acclimated cells to high light triggers the onset of energy quenching close to the core of photosystem II, while prolonged light stress activates NPQ in the antenna. Biochemical analysis indicated a link between the changes in the NPQ site/mechanism and the induction of different LHCX isoforms, which accumulate either in the antenna complexes or in the core complex. By comparing the responses of wild-type cells and transgenic lines with a reduced expression of the major LHCX isoform, LHCX1, we conclude that core complex-associated NPQ is more effective in photoprotection than is the antenna complex. Overall, our data clarify the complex molecular scenario of light responses in diatoms and provide a rationale for the existence of a degenerate family of LHCX proteins in these algae.
Collapse
Affiliation(s)
- Lucilla Taddei
- Sorbonne Université, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, F-75005 Paris, France
| | - Volha U Chukhutsina
- Laboratory of Biophysics and MicroSpectroscopy Research Facility, Wageningen University, 6700ET Wageningen, The Netherlands
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam and LaserLaB Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Bernard Lepetit
- Zukunftskolleg, Department of Plant Ecophysiology, University of Konstanz, 78457 Konstanz, Germany
| | - Giulio Rocco Stella
- Sorbonne Université, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, F-75005 Paris, France
- Department of Biotechnology, University of Verona, I-37134 Verona, Italy
| | - Roberto Bassi
- Department of Biotechnology, University of Verona, I-37134 Verona, Italy
| | - Herbert van Amerongen
- Laboratory of Biophysics and MicroSpectroscopy Research Facility, Wageningen University, 6700ET Wageningen, The Netherlands
| | - Jean-Pierre Bouly
- Sorbonne Université, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, F-75005 Paris, France
| | - Marianne Jaubert
- Sorbonne Université, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, F-75005 Paris, France
| | - Giovanni Finazzi
- Université Grenoble Alpes, Laboratoire de Physiologie Cellulaire et Végétale, Unité Mixte de Recherche 5168, Centre National de la Recherche Scientifique, Institut National Recherche Agronomique, Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biosciences et Biotechnologies de Grenoble, CEA Grenoble, F-38054 Grenoble cedex 9, France
| | - Angela Falciatore
- Sorbonne Université, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, F-75005 Paris, France
| |
Collapse
|
44
|
Giovagnetti V, Han G, Ware MA, Ungerer P, Qin X, Wang WD, Kuang T, Shen JR, Ruban AV. A siphonous morphology affects light-harvesting modulation in the intertidal green macroalga Bryopsis corticulans (Ulvophyceae). PLANTA 2018; 247:1293-1306. [PMID: 29460179 PMCID: PMC5945744 DOI: 10.1007/s00425-018-2854-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 01/20/2018] [Indexed: 05/18/2023]
Abstract
The macroalga Bryopsis corticulans relies on a sustained protective NPQ and a peculiar body architecture to efficiently adapt to the extreme light changes of intertidal shores. During low tides, intertidal algae experience prolonged high light stress. Efficient dissipation of excess light energy, measured as non-photochemical quenching (NPQ) of chlorophyll fluorescence, is therefore required to avoid photodamage. Light-harvesting regulation was studied in the intertidal macroalga Bryopsis corticulans, during high light and air exposure. Photosynthetic capacity and NPQ kinetics were assessed in different filament layers of the algal tufts and in intact chloroplasts to unravel the nature of NPQ in this siphonous green alga. We found that the morphology and pigment composition of the B. corticulans body provides functional segregation between surface sunlit filaments (protective state) and those that are underneath and undergo severe light attenuation (light-harvesting state). In the surface filaments, very high and sustained NPQ gradually formed. NPQ induction was triggered by the formation of transthylakoid proton gradient and independent of the xanthophyll cycle. PsbS and LHCSR proteins seem not to be active in the NPQ mechanism activated by this alga. Our results show that B. corticulans endures excess light energy pressure through a sustained protective NPQ, not related to photodamage, as revealed by the unusually quick restoration of photosystem II (PSII) function in the dark. This might suggest either the occurrence of transient PSII photoinactivation or a fast rate of PSII repair cycle.
Collapse
Affiliation(s)
- Vasco Giovagnetti
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Guangye Han
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Maxwell A Ware
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Petra Ungerer
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Xiaochun Qin
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Wen-Da Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Tingyun Kuang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
- Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima, Naka, Okayama, 700-8530, Japan.
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
| |
Collapse
|
45
|
Méléder V, Jesus B, Barnett A, Barillé L, Lavaud J. Microphytobenthos primary production estimated by hyperspectral reflectance. PLoS One 2018; 13:e0197093. [PMID: 29758047 PMCID: PMC5951593 DOI: 10.1371/journal.pone.0197093] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 04/26/2018] [Indexed: 11/18/2022] Open
Abstract
The use of remote sensing techniques allows monitoring of photosynthesis at the ecosystem level and improves our knowledge of plant primary productivity. The main objective of the current study was to develop a remote sensing based method to measure microphytobenthos (MPB) primary production from intertidal mudflats. This was achieved by coupling hyperspectral radiometry (reflectance, ρ and second derivative, δδ) and PAM-fluorometry (non-sequential light curves, NSLC) measurements. The latter allowed the estimation of primary production using a light use efficiency parameter (LUE) and electron transport rates (ETR) whereas ρ allowed to estimate pigment composition and optical absorption cross-section (a*). Five MPB species representative of the main growth forms: epipelic (benthic motile), epipsammic (benthic motile and non motile) and tychoplanktonic (temporarily resuspended in the water column) were submitted to increasing light intensities from dark to 1950 μmol photons.m-2.s-1. Different fluorescence patterns were observed for the three growth-forms and were linked to their xanthophyll cycle (de-epoxydation state). After spectral reflectance measurements, a* was retrieved using a radiative transfer model and several radiometric indices were tested for their capacity to predict LUE and ETR measured by PAM-fluorometry. Only one radiometric index was not species or growth-form specific, i.e. δδ496/508. This index was named MPBLUE and could be used to predict LUE and ETR. The applicability of this index was tested with simulated bands of a wide variety of hyperspectral sensors at spectral resolutions between 3 and 15 nm of Full Width at Half Maximum (FWHM).
Collapse
Affiliation(s)
- Vona Méléder
- Mer Molécules Santé (MMS)–EA 21 60, Université de Nantes, Nates, France
- * E-mail:
| | - Bruno Jesus
- Mer Molécules Santé (MMS)–EA 21 60, Université de Nantes, Nates, France
- BioISI–Biosystems & Integrative Sciences Institute, Campo Grande University of Lisboa, Faculty of Sciences, Lisboa, Portugal
| | - Alexandre Barnett
- Littoral Environnement et Sociétés (LIENSs)–UMR 7266, CNRS/Université de La Rochelle, Institut du Littoral et de l’Environnement, 2 rue Olympe de Gouges, La Rochelle, France
- Botany and Plant Science–National University of Ireland, Galway, Ireland
| | - Laurent Barillé
- Mer Molécules Santé (MMS)–EA 21 60, Université de Nantes, Nates, France
| | - Johann Lavaud
- Littoral Environnement et Sociétés (LIENSs)–UMR 7266, CNRS/Université de La Rochelle, Institut du Littoral et de l’Environnement, 2 rue Olympe de Gouges, La Rochelle, France
- Takuvik–UMI 3376, CNRS/Université Laval, Département de Biologie, Pavillon Alexandre Vachon, Québec, Canada
| |
Collapse
|
46
|
Reduced vacuolar β-1,3-glucan synthesis affects carbohydrate metabolism as well as plastid homeostasis and structure in Phaeodactylum tricornutum. Proc Natl Acad Sci U S A 2018; 115:4791-4796. [PMID: 29669920 DOI: 10.1073/pnas.1719274115] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The β-1,3-glucan chrysolaminarin is the main storage polysaccharide of diatoms. In contrast to plants and green algae, diatoms and most other algal groups do not accumulate storage polysaccharides in their plastids. The diatom Phaeodactylum tricornutum possesses only a single gene encoding a putative β-1,3-glucan synthase (PtBGS). Here, we characterize this enzyme by expressing GFP fusion proteins in P. tricornutum and by creating and investigating corresponding gene silencing mutants. We demonstrate that PtBGS is a vacuolar protein located in the tonoplast. Metabolite analyses of two mutant strains with reduced amounts of PtBGS reveal a reduction in their chrysolaminarin content and an increase of soluble sugars and lipids. This indicates that carbohydrates are shunted into alternative pathways when chrysolaminarin production is impaired. The mutant strains show reduced growth and lower photosynthetic capacities, while possessing higher photoprotective abilities than WT cells. Interestingly, a strong reduction in PtBGS expression also results in aberrations of the usually very regular thylakoid membrane patterns, including increased thylakoid thickness, reduced numbers of thylakoids per plastid, and increased numbers of lamellae per thylakoid stack. Our data demonstrate the complex intertwinement of carbohydrate storage in the vacuoles with carbohydrate metabolism, photosynthetic homeostasis, and plastid morphology.
Collapse
|
47
|
LHCSR Expression under HSP70/RBCS2 Promoter as a Strategy to Increase Productivity in Microalgae. Int J Mol Sci 2018; 19:ijms19010155. [PMID: 29303960 PMCID: PMC5796104 DOI: 10.3390/ijms19010155] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 12/24/2017] [Accepted: 12/31/2017] [Indexed: 11/17/2022] Open
Abstract
Microalgae are unicellular photosynthetic organisms considered as potential alternative sources for biomass, biofuels or high value products. However, limited biomass productivity is commonly experienced in their cultivating system despite their high potential. One of the reasons for this limitation is the high thermal dissipation of the light absorbed by the outer layers of the cultures exposed to high light caused by the activation of a photoprotective mechanism called non-photochemical quenching (NPQ). In the model organism for green algae Chlamydomonas reinhardtii, NPQ is triggered by pigment binding proteins called light-harvesting-complexes-stress-related (LHCSRs), which are over-accumulated in high light. It was recently reported that biomass productivity can be increased both in microalgae and higher plants by properly tuning NPQ induction. In this work increased light use efficiency is reported by introducing in C. reinhardtii a LHCSR3 gene under the control of Heat Shock Protein 70/RUBISCO small chain 2 promoter in a npq4 lhcsr1 background, a mutant strain knockout for all LHCSR genes. This complementation strategy leads to a low expression of LHCSR3, causing a strong reduction of NPQ induction but is still capable of protecting from photodamage at high irradiance, resulting in an improved photosynthetic efficiency and higher biomass accumulation.
Collapse
|
48
|
Kroth PG, Wilhelm C, Kottke T. An update on aureochromes: Phylogeny - mechanism - function. JOURNAL OF PLANT PHYSIOLOGY 2017; 217:20-26. [PMID: 28797596 DOI: 10.1016/j.jplph.2017.06.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 06/21/2017] [Accepted: 06/23/2017] [Indexed: 05/20/2023]
Abstract
Light is important for algae, as it warrants metabolic independence via photosynthesis. In addition to the absorption of light by the photosystems, algae possess a variety of specific photoreceptors that allow the quantification of the light fluxes as well as the assessment of light qualities. About a decade ago, aureochromes have been described in the xanthophyte alga Vaucheria frigida. These proteins represent a new type of blue light photoreceptor as they possess both a light-oxygen-voltage (LOV) domain for light reception as well as a basic region leucine zipper (bZIP) domain for DNA binding, indicating that they represent light-driven transcription factors. Aureochromes so far have been detected only in a single group of algae, photosynthetic stramenopiles, but not in any other prokaryotic or eukaryotic organisms. Recent biophysical work on aureochromes in the absence and the presence of DNA revealed the mechanism of allosteric communication between the sensor and effector domains despite their unusual inversed arrangement. Different molecular models have been proposed to describe the effect of light on DNA binding. Functional characterization of mutants of the diatom Phaeodactylum tricornutum, in which the aureochrome genes have been silenced or deleted, indicate that different aureochromes may have different functions, being involved in central processes like light acclimation and regulation of the cell cycle.
Collapse
Affiliation(s)
- Peter G Kroth
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany.
| | - Christian Wilhelm
- Institute of Biology, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany
| | - Tilman Kottke
- Department of Chemistry, Physical and Biophysical Chemistry, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| |
Collapse
|
49
|
Mann M, Serif M, Jakob T, Kroth PG, Wilhelm C. PtAUREO1a and PtAUREO1b knockout mutants of the diatom Phaeodactylum tricornutum are blocked in photoacclimation to blue light. JOURNAL OF PLANT PHYSIOLOGY 2017; 217:44-48. [PMID: 28610707 DOI: 10.1016/j.jplph.2017.05.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 05/22/2017] [Accepted: 05/29/2017] [Indexed: 05/20/2023]
Abstract
Aureochromes are blue light receptors specifically found in photosynthetic Stramenopiles (algae). Four different Aureochromes have been identified in the marine diatom Phaeodactylum tricornutum (PtAUREO 1a, 1b, 1c, and 2). Since blue light is necessary for high light acclimation in diatoms, it has been hypothesized that Aureochromes might play an important role in the light acclimation capacity of diatoms. This hypothesis was supported by an RNAi knockdown line of PtAUREO1a, which showed a phenotype different from wild type cells when grown in either blue or red light. Here, we show for the first time the phenotype and the photoacclimation reaction of TALEN-mediated knockout mutants of PtAUREO1a and PtAUREO1b, clearly proving the necessity of Aureochromes for light acclimation under blue light. However, both mutants do also show specific differences in their respective phenotypes. Hence, PtAUREO1a and 1b are not functionally redundant in photoacclimation to blue light, and their specific contribution needs to be clarified further.
Collapse
Affiliation(s)
- Marcus Mann
- Institute of Biology, Department of Plant Physiology, University of Leipzig, D-04103 Leipzig, Germany.
| | - Manuel Serif
- Plant Ecophysiology, Fachbereich Biologie, Universität Konstanz, D-78457 Konstanz, Germany
| | - Torsten Jakob
- Institute of Biology, Department of Plant Physiology, University of Leipzig, D-04103 Leipzig, Germany
| | - Peter G Kroth
- Plant Ecophysiology, Fachbereich Biologie, Universität Konstanz, D-78457 Konstanz, Germany
| | - Christian Wilhelm
- Institute of Biology, Department of Plant Physiology, University of Leipzig, D-04103 Leipzig, Germany
| |
Collapse
|
50
|
Heydarizadeh P, Boureba W, Zahedi M, Huang B, Moreau B, Lukomska E, Couzinet-Mossion A, Wielgosz-Collin G, Martin-Jézéquel V, Bougaran G, Marchand J, Schoefs B. Response of CO 2-starved diatom Phaeodactylum tricornutum to light intensity transition. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160396. [PMID: 28717022 PMCID: PMC5516105 DOI: 10.1098/rstb.2016.0396] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2017] [Indexed: 12/13/2022] Open
Abstract
In this study, we investigated the responses of Phaeodactylum tricornutum cells acclimated to 300 µmol m-2 s-1 photon flux density to an increase (1000 µmol m-2 s-1) or decrease (30 µmol m-2 s-1) in photon flux densities. The light shift occurred abruptly after 5 days of growth and the acclimation to new conditions was followed during the next 6 days at the physiological and molecular levels. The molecular data reflect a rearrangement of carbon metabolism towards the production of phosphoenolpyruvic acid (PEP) and/or pyruvate. These intermediates were used differently by the cell as a function of the photon flux density: under low light, photosynthesis was depressed while respiration was increased. Under high light, lipids and proteins accumulated. Of great interest, under high light, the genes coding for the synthesis of aromatic amino acids and phenolic compounds were upregulated suggesting that the shikimate pathway was activated.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'.
Collapse
Affiliation(s)
- Parisa Heydarizadeh
- Metabolism, Bioengineering of Microalga Molecules and Applications (MIMMA), Mer Molécules Santé, UBL, IUML-FR 3473 CNRS, University of Le Mans, 72085 Le Mans, France
| | - Wafâa Boureba
- Metabolism, Bioengineering of Microalga Molecules and Applications (MIMMA), Mer Molécules Santé, UBL, IUML-FR 3473 CNRS, University of Le Mans, 72085 Le Mans, France
| | - Morteza Zahedi
- Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, Iran
| | - Bing Huang
- Metabolism, Bioengineering of Microalga Molecules and Applications (MIMMA), Mer Molécules Santé, UBL, IUML-FR 3473 CNRS, University of Le Mans, 72085 Le Mans, France
| | - Brigitte Moreau
- Metabolism, Bioengineering of Microalga Molecules and Applications (MIMMA), Mer Molécules Santé, UBL, IUML-FR 3473 CNRS, University of Le Mans, 72085 Le Mans, France
| | - Ewa Lukomska
- IFREMER, Physiology and Biotechnology of Algae Laboratory, rue de l'Ile d'Yeu, BP 21105, 44311 Nantes, France
| | - Aurélie Couzinet-Mossion
- Faculté des Sciences Pharmaceutiques et Biologiques, Université de Nantes, Groupe Mer, Molécules, Santé-EA 2160, Institut Universitaire Mer et Littoral FR3473 CNRS, 9 rue Bias, BP 61112, 44035 Nantes Cedex 1, France
| | - Gaëtane Wielgosz-Collin
- Faculté des Sciences Pharmaceutiques et Biologiques, Université de Nantes, Groupe Mer, Molécules, Santé-EA 2160, Institut Universitaire Mer et Littoral FR3473 CNRS, 9 rue Bias, BP 61112, 44035 Nantes Cedex 1, France
| | | | - Gaël Bougaran
- IFREMER, Physiology and Biotechnology of Algae Laboratory, rue de l'Ile d'Yeu, BP 21105, 44311 Nantes, France
| | - Justine Marchand
- Metabolism, Bioengineering of Microalga Molecules and Applications (MIMMA), Mer Molécules Santé, UBL, IUML-FR 3473 CNRS, University of Le Mans, 72085 Le Mans, France
| | - Benoît Schoefs
- Metabolism, Bioengineering of Microalga Molecules and Applications (MIMMA), Mer Molécules Santé, UBL, IUML-FR 3473 CNRS, University of Le Mans, 72085 Le Mans, France
| |
Collapse
|