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Hüner NPA, Ivanov AG, Szyszka-Mroz B, Savitch LV, Smith DR, Kata V. Photostasis and photosynthetic adaptation to polar life. PHOTOSYNTHESIS RESEARCH 2024; 161:51-64. [PMID: 38865029 DOI: 10.1007/s11120-024-01104-7] [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: 04/24/2024] [Accepted: 05/29/2024] [Indexed: 06/13/2024]
Abstract
Photostasis is the light-dependent maintenance of energy balance associated with cellular homeostasis in photoautotrophs. We review evidence that illustrates how photosynthetic adaptation in polar photoautrophs such as aquatic green algae, cyanobacteria, boreal conifers as well as terrestrial angiosperms exhibit an astonishing plasticity in structure and function of the photosynthetic apparatus. This plasticity contributes to the maintenance of photostasis, which is essential for the long-term survival in the seemingly inhospitable Antarctic and Arctic habitats. However, evidence indicates that polar photoautrophic species exhibit different functional solutions for the maintenance of photostasis. We suggest that this reflects, in part, the genetic diversity symbolized by inherent genetic redundancy characteristic of polar photoautotrophs which enhances their survival in a thermodynamically challenging environment.
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Affiliation(s)
- Norman P A Hüner
- Department of Biology, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada.
| | - Alexander G Ivanov
- Department of Biology, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl. 21, Sofia, 1113, Bulgaria
| | - Beth Szyszka-Mroz
- Department of Biology, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
| | - Leonid V Savitch
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, K1A OC6, Canada
| | - David R Smith
- Department of Biology, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
| | - Victoria Kata
- Department of Biology, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
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2
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Deore P, Tsang Min Ching SJ, Nitschke MR, Rudd D, Brumley DR, Hinde E, Blackall LL, van Oppen MJH. Unique photosynthetic strategies employed by closely related Breviolum minutum strains under rapid short-term cumulative heat stress. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:4005-4023. [PMID: 38636949 PMCID: PMC11233414 DOI: 10.1093/jxb/erae170] [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: 11/20/2023] [Accepted: 04/17/2024] [Indexed: 04/20/2024]
Abstract
The thermal tolerance of symbiodiniacean photo-endosymbionts largely underpins the thermal bleaching resilience of their cnidarian hosts such as corals and the coral model Exaiptasia diaphana. While variation in thermal tolerance between species is well documented, variation between conspecific strains is understudied. We compared the thermal tolerance of three closely related strains of Breviolum minutum represented by two internal transcribed spacer region 2 profiles (one strain B1-B1o-B1g-B1p and the other two strains B1-B1a-B1b-B1g) and differences in photochemical and non-photochemical quenching, de-epoxidation state of photopigments, and accumulation of reactive oxygen species under rapid short-term cumulative temperature stress (26-40 °C). We found that B. minutum strains employ distinct photoprotective strategies, resulting in different upper thermal tolerances. We provide evidence for previously unknown interdependencies between thermal tolerance traits and photoprotective mechanisms that include a delicate balancing of excitation energy and its dissipation through fast relaxing and state transition components of non-photochemical quenching. The more thermally tolerant B. minutum strain (B1-B1o-B1g-B1p) exhibited an enhanced de-epoxidation that is strongly linked to the thylakoid membrane melting point and possibly membrane rigidification minimizing oxidative damage. This study provides an in-depth understanding of photoprotective mechanisms underpinning thermal tolerance in closely related strains of B. minutum.
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Affiliation(s)
- Pranali Deore
- School of BioSciences, The University of Melbourne, Parkville 3010, Victoria, Australia
| | | | - Matthew R Nitschke
- Australian Institute of Marine Science, Townsville 4810, Queensland, Australia
- School of Biological Sciences, Victoria University of Wellington, Wellington 6102, New Zealand
| | - David Rudd
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Douglas R Brumley
- School of Mathematics and Statistics, The University of Melbourne, Parkville 3010, Victoria, Australia
| | - Elizabeth Hinde
- School of Physics, The University of Melbourne, Parkville 3010, Victoria, Australia
| | - Linda L Blackall
- School of BioSciences, The University of Melbourne, Parkville 3010, Victoria, Australia
| | - Madeleine J H van Oppen
- School of BioSciences, The University of Melbourne, Parkville 3010, Victoria, Australia
- Australian Institute of Marine Science, Townsville 4810, Queensland, Australia
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3
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Liu M, Wang Y, Zhang H, Hao Y, Wu H, Shen H, Zhang P. Mechanisms of photoprotection in overwintering evergreen conifers: Sustained quenching of chlorophyll fluorescence. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 210:108638. [PMID: 38653096 DOI: 10.1016/j.plaphy.2024.108638] [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: 11/12/2023] [Revised: 04/15/2024] [Accepted: 04/16/2024] [Indexed: 04/25/2024]
Abstract
Evergreen conifers growing in high-latitude regions must endure prolonged winters that are characterized by sub-zero temperatures combined with light, conditions that can cause significant photooxidative stress. Understanding overwintering mechanisms is crucial for addressing winter adversity in temperate forest ecosystems and enhancing the ability of conifers to adapt to climate change. This review synthesizes the current understanding of the photoprotective mechanisms that conifers employ to mitigate photooxidative stress, particularly non-photochemical "sustained quenching", the mechanism of which is hypothesized to be a recombination or deformation of the original mechanism employed by conifers in response to short-term low temperature and intense light stress in the past. Based on this hypothesis, scattered studies in this field are assembled and integrated into a complete mechanism of sustained quenching embedded in the adaptation process of plant physiology. It also reveals which parts of the whole system have been verified in conifers and which have only been verified in non-conifers, and proposes specific directions for future research. The functional implications of studies of non-coniferous plant species for the study of coniferous trees are also considered, as a wide range of plant responses lead to sustained quenching, even among different conifer species. In addition, the review highlights the challenges of measuring sustained quenching and discusses the application of ultrafast-time-resolved fluorescence and decay-associated spectra for the elucidation of photosynthetic principles.
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Affiliation(s)
- Mingyu Liu
- College of Forestry, Northeast Forestry University, Harbin, 150040, China.
| | - Yu Wang
- College of Life Sciences, Northeast Forestry University, Harbin, 150040, China.
| | - Huihui Zhang
- College of Life Sciences, Northeast Forestry University, Harbin, 150040, China.
| | - Yuanqin Hao
- College of Forestry, Northeast Forestry University, Harbin, 150040, China.
| | - Haibo Wu
- College of Forestry, Northeast Forestry University, Harbin, 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management, Ministry of Education, Northeast Forestry University, Harbin, 150040, China; State Forestry and Grassland Administration Engineering Technology Research Center of Korean Pine, Harbin, 150040, China.
| | - Hailong Shen
- College of Forestry, Northeast Forestry University, Harbin, 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management, Ministry of Education, Northeast Forestry University, Harbin, 150040, China; State Forestry and Grassland Administration Engineering Technology Research Center of Korean Pine, Harbin, 150040, China.
| | - Peng Zhang
- College of Forestry, Northeast Forestry University, Harbin, 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management, Ministry of Education, Northeast Forestry University, Harbin, 150040, China; State Forestry and Grassland Administration Engineering Technology Research Center of Korean Pine, Harbin, 150040, China.
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4
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Zhao LS, Wang N, Li K, Li CY, Guo JP, He FY, Liu GM, Chen XL, Gao J, Liu LN, Zhang YZ. Architecture of symbiotic dinoflagellate photosystem I-light-harvesting supercomplex in Symbiodinium. Nat Commun 2024; 15:2392. [PMID: 38493166 PMCID: PMC10944487 DOI: 10.1038/s41467-024-46791-x] [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: 10/19/2023] [Accepted: 03/11/2024] [Indexed: 03/18/2024] Open
Abstract
Symbiodinium are the photosynthetic endosymbionts for corals and play a vital role in supplying their coral hosts with photosynthetic products, forming the nutritional foundation for high-yield coral reef ecosystems. Here, we determine the cryo-electron microscopy structure of Symbiodinium photosystem I (PSI) supercomplex with a PSI core composed of 13 subunits including 2 previously unidentified subunits, PsaT and PsaU, as well as 13 peridinin-Chl a/c-binding light-harvesting antenna proteins (AcpPCIs). The PSI-AcpPCI supercomplex exhibits distinctive structural features compared to their red lineage counterparts, including extended termini of PsaD/E/I/J/L/M/R and AcpPCI-1/3/5/7/8/11 subunits, conformational changes in the surface loops of PsaA and PsaB subunits, facilitating the association between the PSI core and peripheral antennae. Structural analysis and computational calculation of excitation energy transfer rates unravel specific pigment networks in Symbiodinium PSI-AcpPCI for efficient excitation energy transfer. Overall, this study provides a structural basis for deciphering the mechanisms governing light harvesting and energy transfer in Symbiodinium PSI-AcpPCI supercomplexes adapted to their symbiotic ecosystem, as well as insights into the evolutionary diversity of PSI-LHCI among various photosynthetic organisms.
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Affiliation(s)
- Long-Sheng Zhao
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
- Marine Biotechnology Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao, 266237, China
| | - Ning Wang
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Kang Li
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao, 266237, China
| | - Chun-Yang Li
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao, 266237, China
| | - Jian-Ping Guo
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China
| | - Fei-Yu He
- Marine Biotechnology Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Gui-Ming Liu
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Institute of Biotechnology, Beijing Academy of Agriculture and Forestry Sciences, 100097, Beijing, China
| | - Xiu-Lan Chen
- Marine Biotechnology Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao, 266237, China
| | - Jun Gao
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Lu-Ning Liu
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China.
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK.
| | - Yu-Zhong Zhang
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China.
- Marine Biotechnology Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China.
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao, 266237, China.
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5
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Bhattacharya D, Stephens TG, Chille EE, Benites LF, Chan CX. Facultative lifestyle drives diversity of coral algal symbionts. Trends Ecol Evol 2024; 39:239-247. [PMID: 37953106 DOI: 10.1016/j.tree.2023.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 11/14/2023]
Abstract
The photosynthetic symbionts of corals sustain biodiverse reefs in nutrient-poor, tropical waters. Recent genomic data illuminate the evolution of coral symbionts under genome size constraints and suggest that retention of the facultative lifestyle, widespread among these algae, confers a selective advantage when compared with a strict symbiotic existence. We posit that the coral symbiosis is analogous to a 'bioreactor' that selects winner genotypes and allows them to rise to high numbers in a sheltered habitat prior to release by the coral host. Our observations lead to a novel hypothesis, the 'stepping-stone model', which predicts that local adaptation under both the symbiotic and free-living stages, in a stepwise fashion, accelerates coral alga diversity and the origin of endemic strains and species.
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Affiliation(s)
- Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901, USA.
| | - Timothy G Stephens
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901, USA
| | - Erin E Chille
- Ecology and Evolution Graduate Program, Rutgers University, New Brunswick, NJ 08901, USA
| | - L Felipe Benites
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901, USA
| | - Cheong Xin Chan
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, 4072, QLD, Australia.
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6
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Yokono M, Kim E, Minagawa J. The binding of light-harvesting antennae to PsaB suppresses the PSII to PSI spillover. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148995. [PMID: 37433365 DOI: 10.1016/j.bbabio.2023.148995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/15/2023] [Accepted: 07/05/2023] [Indexed: 07/13/2023]
Affiliation(s)
- Makio Yokono
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki, Japan; Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies, Okazaki, Japan.
| | - Eunchul Kim
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki, Japan; Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies, Okazaki, Japan
| | - Jun Minagawa
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki, Japan; Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies, Okazaki, Japan
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7
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Herdean A, Hall C, Hughes DJ, Kuzhiumparambil U, Diocaretz BC, Ralph PJ. Temperature mapping of non-photochemical quenching in Chlorella vulgaris. PHOTOSYNTHESIS RESEARCH 2023; 155:191-202. [PMID: 36417105 PMCID: PMC9879819 DOI: 10.1007/s11120-022-00981-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 10/25/2022] [Indexed: 06/16/2023]
Abstract
Light intensity and temperature independently impact all parts of the photosynthetic machinery in plants and algae. Yet to date, the vast majority of pulse amplitude modulated (PAM) chlorophyll a fluorescence measurements have been performed at well-defined light intensities, but rarely at well-defined temperatures. In this work, we show that PAM measurements performed at various temperatures produce vastly different results in the chlorophyte Chlorella vulgaris. Using a recently developed Phenoplate technique to map quantum yield of Photosystem II (Y(II)) and non-photochemical quenching (NPQ) as a function of temperature, we show that the fast-relaxing NPQ follows an inverse normal distribution with respect to temperature and appears insensitive to previous temperature acclimation. The slow-relaxing or residual NPQ after 5 minutes of dark recovery follows a normal distribution similar to Y(II) but with a peak in the higher temperature range. Surprisingly, higher slow- and fast-relaxing NPQ values were observed in high-light relative to low-light acclimated cultures. Y(II) values peaked at the adaptation temperature regardless of temperature or light acclimation. Our novel findings show the complete temperature working spectrum of Y(II) and how excess energy quenching is managed across a wide range of temperatures in the model microalgal species C. vulgaris. Finally, we draw attention to the fact that the effect of the temperature component in PAM measurements has been wildly underestimated, and results from experiments at room temperature can be misleading.
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Affiliation(s)
- Andrei Herdean
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia.
| | - Christopher Hall
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia
| | - David J Hughes
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia
| | | | | | - Peter J Ralph
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia
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8
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González-Guerrero LA, Vásquez-Elizondo RM, López-Londoño T, Hernán G, Iglesias-Prieto R, Enríquez S. Validation of parameters and protocols derived from chlorophyll a fluorescence commonly utilised in marine ecophysiological studies. FUNCTIONAL PLANT BIOLOGY : FPB 2022; 49:517-532. [PMID: 34372966 DOI: 10.1071/fp21101] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
This study documents the first validation of the suitability of the most common parameters and protocols used in marine ecophysiology to characterise photosynthesis by means of chlorophyll a fluorescence tools. We demonstrate that the effective yield of PSII (ΔF /F m ') is significantly underestimated when using short inductions times (≤1 min) following the rapid light curve protocol (RLC). The consequent electron transport rates (ETR) underestimations are species-specific and highly variable with irradiance and the photoacclimatory condition of the sample. Our analysis also questions the use of relative descriptors (relETR), as they not only overestimate photosynthesis, but overlook one of the fundamental components of the photosynthetic response: light absorption regulation. Absorptance determinations were fundamental to characterise the ETR response of low-pigmented seagrass leaves, and also uncovered relevant differences between two coral species and the accclimatory response of a cultured dinoflagellate to temperature. ETR and oxygen evolution determinations showed close correlations for all organisms tested with the expected slope of 4 e- per O2 molecule evolved, when correct photosynthesis inductions and light absorption determinations were applied. However, ETR curves cannot be equated to conventional photosynthetic response to irradiance (P vs E ) curves, and caution is needed when using ETR to characterise photosynthesis rates above photosynthesis saturation (E k ). This validation strongly supports the utility of fluorescence tools, underlining the need to correct two decades of propagation of erroneous concepts, protocols and parameters in marine eco-physiology. We aim also to emphasise the importance of optical descriptions for understanding photosynthesis, and for interpreting fluorescence measurements. In combination with conventional gross photosynthesis (GPS) approaches, optical characterisations open an extraordinary opportunity to determine two central parameters of photosynthesis performance: the quantum yield (φmax ) of the process and its minimum quantum requirements (1/φmax ). The combination of both approaches potentiates the possibilities of chlorophyll a fluorescence tools to characterise marine photosynthesis biodiversity.
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Affiliation(s)
| | - Román M Vásquez-Elizondo
- Laboratory of Photobiology of coral reef primary producers, Unidad Académica de Sistemas Arrecifales Puerto Morelos, Universidad Nacional Autónoma de México (UNAM), Apartado Postal 13, 77500 Cancún, Mexico; and Present address: Laboratorio de Ficología Aplicada, Departamento de Recursos del Mar, CINVESTAV, Mérida
| | | | - Gema Hernán
- Laboratory of Photobiology of coral reef primary producers, Unidad Académica de Sistemas Arrecifales Puerto Morelos, Universidad Nacional Autónoma de México (UNAM), Apartado Postal 13, 77500 Cancún, Mexico
| | | | - Susana Enríquez
- Laboratory of Photobiology of coral reef primary producers, Unidad Académica de Sistemas Arrecifales Puerto Morelos, Universidad Nacional Autónoma de México (UNAM), Apartado Postal 13, 77500 Cancún, Mexico; and Corresponding author
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9
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Bleaching physiology: who's the 'weakest link' - host vs. symbiont? Emerg Top Life Sci 2022; 6:17-32. [PMID: 35179208 DOI: 10.1042/etls20210228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 01/20/2022] [Accepted: 02/01/2022] [Indexed: 11/17/2022]
Abstract
Environmental stress, such as an increase in the sea surface temperature, triggers coral bleaching, a profound dysfunction of the mutualist symbiosis between the host cnidarians and their photosynthetic dinoflagellates of the Family Symbiodiniaceae. Because of climate change, mass coral bleaching events will increase in frequency and severity in the future, threatening the persistence of this iconic marine ecosystem at global scale. Strategies adapted to coral reefs preservation and restoration may stem from the identification of the succession of events and of the different molecular and cellular contributors to the bleaching phenomenon. To date, studies aiming to decipher the cellular cascade leading to temperature-related bleaching, emphasized the involvement of reactive species originating from compromised bioenergetic pathways (e.g. cellular respiration and photosynthesis). These molecules are responsible for damage to various cellular components causing the dysregulation of cellular homeostasis and the breakdown of symbiosis. In this review, we synthesize the current knowledge available in the literature on the cellular mechanisms caused by thermal stress, which can initiate or participate in the cell cascade leading to the loss of symbionts, with a particular emphasis on the role of each partner in the initiating processes.
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10
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Ivanov AG, Krol M, Savitch LV, Szyszka-Mroz B, Roche J, Sprott DP, Selstam E, Wilson KW, Gardiner R, Öquist G, Hurry VM, Hüner NPA. The decreased PG content of pgp1 inhibits PSI photochemistry and limits reaction center and light-harvesting polypeptide accumulation in response to cold acclimation. PLANTA 2022; 255:36. [PMID: 35015152 DOI: 10.1007/s00425-022-03819-0] [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: 08/10/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
Decreased PG constrains PSI activity due to inhibition of transcript and polypeptide abundance of light-harvesting and reaction center polypeptides generating a reversible, yellow phenotype during cold acclimation of pgp1. Cold acclimation of the Arabidopsis pgp1 mutant at 5 °C resulted in a pale-yellow phenotype with abnormal chloroplast ultrastructure compared to its green phenotype upon growth at 20 °C despite a normal cold-acclimation response at the transcript level. In contrast, wild type maintained its normal green phenotype and chloroplast ultrastructure irrespective of growth temperature. In contrast to cold acclimation of WT, growth of pgp1 at 5 °C limited the accumulation of Lhcbs and Lhcas assessed by immunoblotting. However, a novel 43 kD polypeptide of Lhcb1 as well as a 29 kD polypeptide of Lhcb3 accumulated in the soluble fraction which was absent in the thylakoid membrane fraction of cold-acclimated pgp1 which was not observed in WT. Cold acclimation of pgp1 destabilized the Chl-protein complexes associated with PSI and predisposed energy distribution in favor of PSII rather than PSI compared to the WT. Functionally, in vivo PSI versus PSII photochemistry was inhibited in cold-acclimated pgp1 to a greater extent than in WT relative to controls. Greening of the pale-yellow pgp1 was induced when cold-acclimated pgp1 was shifted from 5 to 20 °C which resulted in a marked decrease in excitation pressure to a level comparable to WT. Concomitantly, Lhcbs and Lhcas accumulated with a simultaneous decrease in the novel 43 and 29kD polypeptides. We conclude that the reduced levels of phosphatidyldiacylglycerol in the pgp1 limit the capacity of the mutant to maintain the structure and function of its photosynthetic apparatus during cold acclimation. Thus, maintenance of normal thylakoid phosphatidyldiacylglycerol levels is essential to stabilize the photosynthetic apparatus during cold acclimation.
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Affiliation(s)
- Alexander G Ivanov
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7, Canada
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl. 21, 1113, Sofia, Bulgaria
| | - Marianna Krol
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Leonid V Savitch
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, K1A OC6, Canada
| | - Beth Szyszka-Mroz
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Jessica Roche
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7, Canada
- , 6/136 Austin St, Mt. Victoria, Wellington, 6011, New Zealand
| | - D P Sprott
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, K1A OC6, Canada
| | - Eva Selstam
- Department of Plant Physiology, Umeå Plant Science Centre, University of Umeå, 90187, Umeå, Sweden
| | - Kenneth W Wilson
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Richard Gardiner
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Gunnar Öquist
- Department of Plant Physiology, Umeå Plant Science Centre, University of Umeå, 90187, Umeå, Sweden
| | - Vaughan M Hurry
- Department of Plant Physiology, Umeå Plant Science Centre, University of Umeå, 90187, Umeå, Sweden
| | - Norman P A Hüner
- Department of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, ON, N6A 5B7, Canada.
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11
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Wang H, Wu F, Li M, Zhu X, Shi C, Shao C, Ding G. Structure and chlorophyll fluorescence of heteroblastic foliage affect first-year growth in Pinus massoniana Lamb. seedlings. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 170:206-217. [PMID: 34906903 DOI: 10.1016/j.plaphy.2021.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/22/2021] [Accepted: 12/07/2021] [Indexed: 06/14/2023]
Abstract
Pine seedlings exhibit heteroblastic foliage (primary and secondary needles) during seedling development. However, few trials have studied how heteroblastic foliage influences pine seedling growth by seasonal variation. This study first investigated the anatomical differences between the primary and secondary needles of one-year-old Pinus massoniana seedlings. We measured chlorophyll fluorescence (ChlF) and evaluated the photoprotective mechanisms and light energy partitioning of these heteroblastic leaves from September to November. The results showed that the primary needles, as juvenile foliage, had a greater fraction of mesophyll tissue and stomata. In addition, the primary needles had two vascular bundles, and shorter distance from xylem and phloem to mesophyll cells, exhibiting a luxury growth strategy of rapidly obtaining high returns. The ChlF parameters indicated that the primary needles maintained a relatively high level of photoprotection by thermal dissipation (nonphotochemical quenching (NPQ)) and nonregulated energy dissipation (Y(NO)). The secondary needles, representing mature foliage, had greater area of xylem and phloem tissues. The contents of Chl b and carotenoids (Car) significantly increased in November, promoting φPo and photoprotection, which suggested that the secondary needles were more resistant to low temperatures. During the whole light response process of secondary needles, the increases in the electron transfer rate (ETR) and light energy utilization efficiency (α) helped to increase the actual photosynthetic quantum yield (Y(II)) by reducing energy dissipation by decreasing the proportion of regulated energy dissipation (Y(NPQ)) and Y(NO). Given the sensitivity of this heteroblastic foliage to environmental changes, the practical use and extension of P. massoniana for afforestation purposes should be carried out with caution.
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Affiliation(s)
- Haoyun Wang
- Institute for Forest Resources and Environment of Guizhou, Guizhou University, Guiyang, 550025, China; Key Laboratory of Forest Cultivation in Plateau Mountain of Guizhou Province, Guizhou University, Guiyang, 550025, China; College of Forestry, Guizhou University, Guiyang, 550025, China
| | - Feng Wu
- Institute for Forest Resources and Environment of Guizhou, Guizhou University, Guiyang, 550025, China; Key Laboratory of Forest Cultivation in Plateau Mountain of Guizhou Province, Guizhou University, Guiyang, 550025, China; College of Forestry, Guizhou University, Guiyang, 550025, China.
| | - Min Li
- College of Forestry, Guizhou University, Guiyang, 550025, China
| | - Xiaokun Zhu
- College of Forestry, Guizhou University, Guiyang, 550025, China
| | - Changshuang Shi
- College of Forestry, Guizhou University, Guiyang, 550025, China
| | - Changchang Shao
- College of Forestry, Guizhou University, Guiyang, 550025, China
| | - Guijie Ding
- Institute for Forest Resources and Environment of Guizhou, Guizhou University, Guiyang, 550025, China; Key Laboratory of Forest Cultivation in Plateau Mountain of Guizhou Province, Guizhou University, Guiyang, 550025, China; College of Forestry, Guizhou University, Guiyang, 550025, China.
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12
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Williams A, Pathmanathan JS, Stephens TG, Su X, Chiles EN, Conetta D, Putnam HM, Bhattacharya D. Multi-omic characterization of the thermal stress phenome in the stony coral Montipora capitata. PeerJ 2021; 9:e12335. [PMID: 34824906 PMCID: PMC8590396 DOI: 10.7717/peerj.12335] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 09/28/2021] [Indexed: 11/22/2022] Open
Abstract
Background Corals, which form the foundation of biodiverse reef ecosystems, are under threat from warming oceans. Reefs provide essential ecological services, including food, income from tourism, nutrient cycling, waste removal, and the absorption of wave energy to mitigate erosion. Here, we studied the coral thermal stress response using network methods to analyze transcriptomic and polar metabolomic data generated from the Hawaiian rice coral Montipora capitata. Coral nubbins were exposed to ambient or thermal stress conditions over a 5-week period, coinciding with a mass spawning event of this species. The major goal of our study was to expand the inventory of thermal stress-related genes and metabolites present in M. capitata and to study gene-metabolite interactions. These interactions provide the foundation for functional or genetic analysis of key coral genes as well as provide potentially diagnostic markers of pre-bleaching stress. A secondary goal of our study was to analyze the accumulation of sex hormones prior to and during mass spawning to understand how thermal stress may impact reproductive success in M. capitata. Methods M. capitata was exposed to thermal stress during its spawning cycle over the course of 5 weeks, during which time transcriptomic and polar metabolomic data were collected. We analyzed these data streams individually, and then integrated both data sets using MAGI (Metabolite Annotation and Gene Integration) to investigate molecular transitions and biochemical reactions. Results Our results reveal the complexity of the thermal stress phenome in M. capitata, which includes many genes involved in redox regulation, biomineralization, and reproduction. The size and number of modules in the gene co-expression networks expanded from the initial stress response to the onset of bleaching. The later stages involved the suppression of metabolite transport by the coral host, including a variety of sodium-coupled transporters and a putative ammonium transporter, possibly as a response to reduction in algal productivity. The gene-metabolite integration data suggest that thermal treatment results in the activation of animal redox stress pathways involved in quenching molecular oxygen to prevent an overabundance of reactive oxygen species. Lastly, evidence that thermal stress affects reproductive activity was provided by the downregulation of CYP-like genes and the irregular production of sex hormones during the mass spawning cycle. Overall, redox regulation and metabolite transport are key components of the coral animal thermal stress phenome. Mass spawning was highly attenuated under thermal stress, suggesting that global climate change may negatively impact reproductive behavior in this species.
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Affiliation(s)
- Amanda Williams
- Microbial Biology Graduate Program, Rutgers University, New Brunswick, United States
| | - Jananan S Pathmanathan
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, United States
| | - Timothy G Stephens
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, United States
| | - Xiaoyang Su
- Department of Medicine, Division of Endocrinology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, United States.,Metabolomics Shared Resource, Rutgers Cancer Institute of New Jersey, Rutgers University,New Brunswick, United States
| | - Eric N Chiles
- Metabolomics Shared Resource, Rutgers Cancer Institute of New Jersey, Rutgers University,New Brunswick, United States
| | - Dennis Conetta
- Department of Biological Sciences, University of Rhode Island, Kingston, United States
| | - Hollie M Putnam
- Department of Biological Sciences, University of Rhode Island, Kingston, United States
| | - Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, United States
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13
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Phenoplate: An innovative method for assessing interacting effects of temperature and light on non-photochemical quenching in microalgae under chemical stress. N Biotechnol 2021; 66:89-96. [PMID: 34715374 DOI: 10.1016/j.nbt.2021.10.004] [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: 05/13/2021] [Revised: 10/21/2021] [Accepted: 10/23/2021] [Indexed: 10/20/2022]
Abstract
Rapid light curves are one of the most widely used methods for assessing the physiological state of photosynthetic organisms. While the method has been applied in a range of physiological studies over the last 20 years, little progress has been made in adapting it for the new age of multi-parametric phenotyping. In order to advance research that is aimed at evaluating the physiological impact of multiple factors, the Phenoplate was developed: a simultaneous assessment of temperature and light gradients. It was used to measure rapid light curves of three marine microalgae across a temperature gradient and altered phosphate availability. The results revealed that activation of photoprotective mechanisms occurred with high efficiency at lower temperatures, and relaxation of photoprotection was negatively impacted above a certain temperature threshold in Tetraselmis sp. It was observed that Thalassiosira pseudonana and Nannochloropsis oceanica exhibited two unique delayed non-photochemical quenching signatures: in combinations of low light with low temperature, and darkness with high temperature, respectively. These findings demonstrate that the Phenoplate approach can be used as a rapid and simple tool to gain insight into the photobiology of microalgae.
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14
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Bag P, Chukhutsina V, Zhang Z, Paul S, Ivanov AG, Shutova T, Croce R, Holzwarth AR, Jansson S. Direct energy transfer from photosystem II to photosystem I confers winter sustainability in Scots Pine. Nat Commun 2020; 11:6388. [PMID: 33319777 PMCID: PMC7738668 DOI: 10.1038/s41467-020-20137-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 11/13/2020] [Indexed: 11/24/2022] Open
Abstract
Evergreen conifers in boreal forests can survive extremely cold (freezing) temperatures during long dark winter and fully recover during summer. A phenomenon called "sustained quenching" putatively provides photoprotection and enables their survival, but its precise molecular and physiological mechanisms are not understood. To unveil them, here we have analyzed seasonal adjustment of the photosynthetic machinery of Scots pine (Pinus sylvestris) trees by monitoring multi-year changes in weather, chlorophyll fluorescence, chloroplast ultrastructure, and changes in pigment-protein composition. Analysis of Photosystem II and Photosystem I performance parameters indicate that highly dynamic structural and functional seasonal rearrangements of the photosynthetic apparatus occur. Although several mechanisms might contribute to 'sustained quenching' of winter/early spring pine needles, time-resolved fluorescence analysis shows that extreme down-regulation of photosystem II activity along with direct energy transfer from photosystem II to photosystem I play a major role. This mechanism is enabled by extensive thylakoid destacking allowing for the mixing of PSII with PSI complexes. These two linked phenomena play crucial roles in winter acclimation and protection.
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Affiliation(s)
- Pushan Bag
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Volha Chukhutsina
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Department of Life Sciences, Imperial College London, London, UK
| | - Zishan Zhang
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Shandong, China
| | - Suman Paul
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Alexander G Ivanov
- Department of Biology, University of Western Ontario, London, Ontario, Canada
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Tatyana Shutova
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Roberta Croce
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Alfred R Holzwarth
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
| | - Stefan Jansson
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden.
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15
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Velitchkova M, Popova AV, Faik A, Gerganova M, Ivanov AG. Low temperature and high light dependent dynamic photoprotective strategies in Arabidopsis thaliana. PHYSIOLOGIA PLANTARUM 2020; 170:93-108. [PMID: 32315446 DOI: 10.1111/ppl.13111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 06/11/2023]
Abstract
Arabidopsis thaliana has been recognized as a chilling tolerant species based on analysis of resistance to low temperature stress, however, the mechanisms involved in this tolerance are not yet clarified. The low temperature-induced effects are exacerbated when plants are exposed to low temperatures in the presence of high light irradiance but the experimental data on the impact of light intensity during cold stress and its influence during recovery from stress are rather limited. The main objective of this study was to re-examine the photosynthetic responses of A. thaliana plants to short term (6 days) low temperature stress (12/10°C) under optimal (150 μmol m-2 s-1 ) and high light (500 μmol m-2 s-1 ) intensity and the subsequent recovery from the stress. Simultaneous measurements of the in vivo and in vitro functional performance of both photosystem II (PSII) and photosystem I (PSI), as well as, net photosynthesis, low temperature (77 K) chlorophyll fluorescence and immunoblot analysis of the relative abundance of PSII and PSI reaction center proteins were used to evaluate the role of light in the development of possible protective mechanisms during low temperature stress and the consequent recovery from exposure to low temperature and different light intensities. The results presented clearly suggest that Arabidopsis plants can employ a number of highly dynamic photoprotective strategies depending on the light intensity. These strategies include one based on LHCII quenching and two other quenching mechanisms localized within the PSII and PSI reaction centers, which are all expressed to different extent depending on the severity of the photoinhibitory treatments under low temperature stress conditions.
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Affiliation(s)
- Maya Velitchkova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev str. Bl. 21, 1113, Sofia, Bulgaria
| | - Antoaneta V Popova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev str. Bl. 21, 1113, Sofia, Bulgaria
| | - Aygyun Faik
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev str. Bl. 21, 1113, Sofia, Bulgaria
| | - Milena Gerganova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev str. Bl. 21, 1113, Sofia, Bulgaria
| | - Alexander G Ivanov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev str. Bl. 21, 1113, Sofia, Bulgaria
- Department of Biology, University of Western Ontario, 1151 Richmond Str. N, London, Ontario, N6A 5B7, Canada
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17
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Sun F, Yang H, Wang G, Shi Q. Combination Analysis of Metatranscriptome and Metagenome Reveal the Composition and Functional Response of Coral Symbionts to Bleaching During an El Niño Event. Front Microbiol 2020; 11:448. [PMID: 32265879 PMCID: PMC7104784 DOI: 10.3389/fmicb.2020.00448] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 03/02/2020] [Indexed: 01/12/2023] Open
Abstract
With the abnormal rise in ocean temperatures globally in recent years, coral bleaching is becoming common and serious. However, the response mechanisms and processes of coral symbionts to bleaching are not well understood. In this study, metagenomics and metatranscriptomics were used to explore the composition of coral symbionts and their functions in response to coral bleaching. All four bleaching coral species displayed a significant reduction of the abundance and function of Dinophyceae-like eukaryotes at the DNA and RNA levels. However, different species of bleaching coral have their own characteristic symbiotic components. Bleaching Acropora tenuis and Goniastrea minuta corals exhibited a very high abundance of prokaryotes and associated gene functions, especially for opportunistic bacteria. In contrast, algae and fungi were identified as the main microbial associate components and had relatively high RNA abundance in bleaching Pocillopora verrucosa and Pocillopora meandrina. Different coral species, whether unbleached or bleaching, have the same symbiotic taxa that perform the same biological functions in vivo. Different stages of bleaching, or transitional states, were identified by different genome content and functional gene abundance among bleaching corals. These stages should be considered in future coral bleaching studies to accurately determine symbiont structure and function. An implicit hypothesis is that there is a causal relationship between the stability of eukaryotic communities and coral bleaching.
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Affiliation(s)
- Fulin Sun
- South China Sea Institute of Oceanology, Institute of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China.,State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,Daya Bay Marine Biology Research Station, Chinese Academy of Sciences, Shenzhen, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Hongqiang Yang
- South China Sea Institute of Oceanology, Institute of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China.,Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,Nansha Marine Ecological and Environmental Research Station, Chinese Academy of Sciences, Sansha, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Guan Wang
- South China Sea Institute of Oceanology, Institute of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China.,Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Qi Shi
- South China Sea Institute of Oceanology, Institute of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China.,Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
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18
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Alves Monteiro HJ, Brahmi C, Mayfield AB, Vidal-Dupiol J, Lapeyre B, Le Luyer J. Molecular mechanisms of acclimation to long-term elevated temperature exposure in marine symbioses. GLOBAL CHANGE BIOLOGY 2020; 26:1271-1284. [PMID: 31692206 DOI: 10.1111/gcb.14907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 10/02/2019] [Indexed: 06/10/2023]
Abstract
Seawater temperature rise in French Polynesia has repeatedly resulted in the bleaching of corals and giant clams. Because giant clams possess distinctive ectosymbiotic features, they represent a unique and powerful model for comparing molecular pathways involved in (a) maintenance of symbiosis and (b) acquisition of thermotolerance among coral reef organisms. Herein, we explored the physiological and transcriptomic responses of the clam hosts and their photosynthetically active symbionts over a 65 day experiment in which clams were exposed to either normal or environmentally relevant elevated seawater temperatures. Additionally, we used metabarcoding data coupled with in situ sampling/survey data to explore the relative importance of holobiont adaptation (i.e., a symbiont community shift) versus acclimation (i.e., physiological changes at the molecular level) in the clams' responses to environmental change. We finally compared transcriptomic data to publicly available genomic datasets for Symbiodiniaceae dinoflagellates (both cultured and in hospite with the coral Pocillopora damicornis) to better tease apart the responses of both hosts and specific symbiont genotypes in this mutualistic association. Gene module preservation analysis revealed that the function of the symbionts' photosystem II was impaired at high temperature, and this response was also found across all holobionts and Symbiodiniaceae lineages examined. Similarly, epigenetic modulation appeared to be a key response mechanism for symbionts in hospite with giant clams exposed to high temperatures, and such modulation was able to distinguish thermotolerant from thermosensitive Cladocopium goreaui ecotypes; epigenetic processes may, then, represent a promising research avenue for those interested in coral reef conservation in this era of changing global climate.
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Affiliation(s)
| | - Chloé Brahmi
- Université de la Polynésie Française, UMR Ecosystèmes Insulaires Océaniens, Ifremer, ILM, IRD, Tahiti, Polynésie Française
| | - Anderson B Mayfield
- National Museum of Marine Biology and Aquarium, Checheng, Taiwan
- Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration, Miami, FL, USA
| | | | - Bruno Lapeyre
- EPHE-CNRS-UPVD, USR3278-CRIOBE, Labex CORAIL, Moorea, Polynésie Française
| | - Jérémy Le Luyer
- IFREMER, UMR Ecosystèmes Insulaires Océaniens, UPF, ILM, IRD, Tahiti, Polynésie Française
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19
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Hadjioannou L, Jimenez C, Rottier C, Sfenthourakis S, Ferrier-Pagès C. Response of the temperate scleractinian coral Cladocora caespitosa to high temperature and long-term nutrient enrichment. Sci Rep 2019; 9:14229. [PMID: 31578398 PMCID: PMC6775152 DOI: 10.1038/s41598-019-50716-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 09/13/2019] [Indexed: 12/11/2022] Open
Abstract
Anthropogenic nutrient enrichment and increased seawater temperatures are responsible for coral reef decline. In particular, they disrupt the relationship between corals and their dinoflagellate symbionts (bleaching). However, some coral species can afford either high temperatures or nutrient enrichment and their study can bring new insights into how corals acclimate or adapt to stressors. Here, we focused on the role of the nutrient history in influencing the response of the Mediterranean scleractinian coral Cladocora caespitosa to thermal stress. Colonies living naturally in nutrient-poor (<0.5 µM nitrogen, <0.2 µM phosphorus, LN) and nutrient-rich (ca. 10–20 µM nitrogen, 0.4 µM phosphorus, HN) locations were sampled, maintained under the right nutrient conditions, and exposed to a temperature increase from 17 °C to 24 °C and 29 °C. While both HN and LN colonies decreased their concentrations of symbionts and/or photosynthetic pigments, HN colonies were able to maintain significant higher rates of net and gross photosynthesis at 24 °C compared to LN colonies. In addition, while there was no change in protein concentration in HN corals during the experiment, proteins continuously decreased in LN corals with increased temperature. These results are important in that they show that nutrient history can influence the response of scleractinian corals to thermal stress. Further investigations of under-studied coral groups are thus required in the future to understand the processes leading to coral resistance to environmental perturbations.
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Affiliation(s)
- Louis Hadjioannou
- Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus. .,Enalia Physis Environmental Research Centre, (ENALIA), Acropoleos 2, Aglantzia 2101, Nicosia, Cyprus.
| | - Carlos Jimenez
- Enalia Physis Environmental Research Centre, (ENALIA), Acropoleos 2, Aglantzia 2101, Nicosia, Cyprus.,Energy, Environment and Water Research Centre (EEWRC) of The Cyprus Institute, Nicosia, Cyprus
| | - Cecile Rottier
- Marine Department, Ecophysiology team, Centre Scientifique de Monaco, Monaco, 98000, Monaco
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20
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Kaňa R, Kotabová E, Šedivá B, Kuthanová Trsková E. Photoprotective strategies in the motile cryptophyte alga Rhodomonas salina-role of non-photochemical quenching, ions, photoinhibition, and cell motility. Folia Microbiol (Praha) 2019; 64:691-703. [PMID: 31352667 DOI: 10.1007/s12223-019-00742-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 07/15/2019] [Indexed: 12/20/2022]
Abstract
We explored photoprotective strategies in a cryptophyte alga Rhodomonas salina. This cryptophytic alga represents phototrophs where chlorophyll a/c antennas in thylakoids are combined with additional light-harvesting system formed by phycobiliproteins in the chloroplast lumen. The fastest response to excessive irradiation is induction of non-photochemical quenching (NPQ). The maximal NPQ appears already after 20 s of excessive irradiation. This initial phase of NPQ is sensitive to Ca2+ channel inhibitor (diltiazem) and disappears, also, in the presence of non-actin, an ionophore for monovalent cations. The prolonged exposure to high light of R. salina cells causes photoinhibition of photosystem II (PSII) that can be further enhanced when Ca2+ fluxes are inhibited by diltiazem. The light-induced reduction in PSII photochemical activity is smaller when compared with immotile diatom Phaeodactylum tricornutum. We explain this as a result of their different photoprotective strategies. Besides the protective role of NPQ, the motile R. salina also minimizes high light exposure by increased cell velocity by almost 25% percent (25% from 82 to 104 μm/s). We suggest that motility of algal cells might have a photoprotective role at high light because algal cell rotation around longitudinal axes changes continual irradiation to periodically fluctuating light.
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Affiliation(s)
- Radek Kaňa
- Institute of Microbiology, Centre ALGATECH, Czech Academy of Sciences, Třeboň, Czech Republic.
| | - Eva Kotabová
- Institute of Microbiology, Centre ALGATECH, Czech Academy of Sciences, Třeboň, Czech Republic
| | - Barbora Šedivá
- Institute of Microbiology, Centre ALGATECH, Czech Academy of Sciences, Třeboň, Czech Republic
| | - Eliška Kuthanová Trsková
- Institute of Microbiology, Centre ALGATECH, Czech Academy of Sciences, Třeboň, Czech Republic.,Student of Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
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21
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Nimmo IC, Barbrook AC, Lassadi I, Chen JE, Geisler K, Smith AG, Aranda M, Purton S, Waller RF, Nisbet RER, Howe CJ. Genetic transformation of the dinoflagellate chloroplast. eLife 2019; 8:45292. [PMID: 31317866 PMCID: PMC6639071 DOI: 10.7554/elife.45292] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 07/06/2019] [Indexed: 01/02/2023] Open
Abstract
Coral reefs are some of the most important and ecologically diverse marine environments. At the base of the reef ecosystem are dinoflagellate algae, which live symbiotically within coral cells. Efforts to understand the relationship between alga and coral have been greatly hampered by the lack of an appropriate dinoflagellate genetic transformation technology. By making use of the plasmid-like fragmented chloroplast genome, we have introduced novel genetic material into the dinoflagellate chloroplast genome. We have shown that the introduced genes are expressed and confer the expected phenotypes. Genetically modified cultures have been grown for 1 year with subculturing, maintaining the introduced genes and phenotypes. This indicates that cells continue to divide after transformation and that the transformation is stable. This is the first report of stable chloroplast transformation in dinoflagellate algae.
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Affiliation(s)
- Isabel C Nimmo
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Adrian C Barbrook
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Imen Lassadi
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Jit Ern Chen
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.,Jeffrey Sachs Center on Sustainable Development, Sunway University, Bandar Sunway, Malaysia
| | - Katrin Geisler
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Alison G Smith
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Manuel Aranda
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Saul Purton
- Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Ross F Waller
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - R Ellen R Nisbet
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Christopher J Howe
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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22
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Chukhutsina VU, Holzwarth AR, Croce R. Time-resolved fluorescence measurements on leaves: principles and recent developments. PHOTOSYNTHESIS RESEARCH 2019; 140:355-369. [PMID: 30478711 PMCID: PMC6509100 DOI: 10.1007/s11120-018-0607-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 11/15/2018] [Indexed: 05/03/2023]
Abstract
Photosynthesis starts when a pigment in the photosynthetic antennae absorbs a photon. The electronic excitation energy is then transferred through the network of light-harvesting pigments to special chlorophyll (Chl) molecules in the reaction centres, where electron transfer is initiated. Energy transfer and primary electron transfer processes take place on timescales ranging from femtoseconds to nanoseconds, and can be monitored in real time via time-resolved fluorescence spectroscopy. This method is widely used for measurements on unicellular photosynthetic organisms, isolated photosynthetic membranes, and individual complexes. Measurements on intact leaves remain a challenge due to their high structural heterogeneity, high scattering, and high optical density, which can lead to optical artefacts. However, detailed information on the dynamics of these early steps, and the underlying structure-function relationships, is highly informative and urgently required in order to get deeper insights into the physiological regulation mechanisms of primary photosynthesis. Here, we describe a current methodology of time-resolved fluorescence measurements on intact leaves in the picosecond to nanosecond time range. Principles of fluorescence measurements on intact leaves, possible sources of alterations of fluorescence kinetics and the ways to overcome them are addressed. We also describe how our understanding of the organisation and function of photosynthetic proteins and energy flow dynamics in intact leaves can be enriched through the application of time-resolved fluorescence spectroscopy on leaves. For that, an example of a measurement on Zea mays leaves is presented.
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Affiliation(s)
- Volha U Chukhutsina
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam and LaserLaB Amsterdam, 1081 HV, Amsterdam, The Netherlands
| | - Alfred R Holzwarth
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam and LaserLaB Amsterdam, 1081 HV, Amsterdam, The Netherlands
| | - Roberta Croce
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam and LaserLaB Amsterdam, 1081 HV, Amsterdam, The Netherlands.
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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: 47] [Impact Index Per Article: 9.4] [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.
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Affiliation(s)
- Claudia Büchel
- Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt, Germany.
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Morris LA, Voolstra CR, Quigley KM, Bourne DG, Bay LK. Nutrient Availability and Metabolism Affect the Stability of Coral-Symbiodiniaceae Symbioses. Trends Microbiol 2019; 27:678-689. [PMID: 30987816 DOI: 10.1016/j.tim.2019.03.004] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/28/2019] [Accepted: 03/13/2019] [Indexed: 01/19/2023]
Abstract
Coral reefs rely upon the highly optimized coral-Symbiodiniaceae symbiosis, making them sensitive to environmental change and susceptible to anthropogenic stress. Coral bleaching is predominantly attributed to photo-oxidative stress, yet nutrient availability and metabolism underpin the stability of symbioses. Recent studies link symbiont proliferation under nutrient enrichment to bleaching; however, the interactions between nutrients and symbiotic stability are nuanced. Here, we demonstrate how bleaching is regulated by the forms and ratios of available nutrients and their impacts on autotrophic carbon metabolism, rather than algal symbiont growth. By extension, historical nutrient conditions mediate host-symbiont compatibility and bleaching tolerance over proximate and evolutionary timescales. Renewed investigations into the coral nutrient metabolism will be required to truly elucidate the cellular mechanisms leading to coral bleaching.
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Affiliation(s)
- Luke A Morris
- AIMS@JCU, Australian Institute of Marine Science, College of Science and Engineering, James Cook University, Townsville, Australia; Australian Institute of Marine Science, Townsville, Australia; College of Science and Engineering, James Cook University, Townsville, Australia. https://twitter.com/ReefLuke
| | - Christian R Voolstra
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia. https://twitter.com/reefgenomics
| | - Kate M Quigley
- AIMS@JCU, Australian Institute of Marine Science, College of Science and Engineering, James Cook University, Townsville, Australia; Australian Institute of Marine Science, Townsville, Australia. https://twitter.com/la__cientifica
| | - David G Bourne
- AIMS@JCU, Australian Institute of Marine Science, College of Science and Engineering, James Cook University, Townsville, Australia; Australian Institute of Marine Science, Townsville, Australia; College of Science and Engineering, James Cook University, Townsville, Australia
| | - Line K Bay
- AIMS@JCU, Australian Institute of Marine Science, College of Science and Engineering, James Cook University, Townsville, Australia; Australian Institute of Marine Science, Townsville, Australia.
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Guzman C, Han X, Shoguchi E, Chormaic SN. Fluorescence from a single Symbiodinium cell. Methods Appl Fluoresc 2018; 6:035003. [DOI: 10.1088/2050-6120/aaba89] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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26
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27
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Suggett DJ, Warner ME, Leggat W. Symbiotic Dinoflagellate Functional Diversity Mediates Coral Survival under Ecological Crisis. Trends Ecol Evol 2017; 32:735-745. [DOI: 10.1016/j.tree.2017.07.013] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 07/30/2017] [Accepted: 07/31/2017] [Indexed: 11/30/2022]
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28
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Flori S, Jouneau PH, Bailleul B, Gallet B, Estrozi LF, Moriscot C, Bastien O, Eicke S, Schober A, Bártulos CR, Maréchal E, Kroth PG, Petroutsos D, Zeeman S, Breyton C, Schoehn G, Falconet D, Finazzi G. Plastid thylakoid architecture optimizes photosynthesis in diatoms. Nat Commun 2017. [PMID: 28631733 PMCID: PMC5481826 DOI: 10.1038/ncomms15885] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Photosynthesis is a unique process that allows independent colonization of the land by plants and of the oceans by phytoplankton. Although the photosynthesis process is well understood in plants, we are still unlocking the mechanisms evolved by phytoplankton to achieve extremely efficient photosynthesis. Here, we combine biochemical, structural and in vivo physiological studies to unravel the structure of the plastid in diatoms, prominent marine eukaryotes. Biochemical and immunolocalization analyses reveal segregation of photosynthetic complexes in the loosely stacked thylakoid membranes typical of diatoms. Separation of photosystems within subdomains minimizes their physical contacts, as required for improved light utilization. Chloroplast 3D reconstruction and in vivo spectroscopy show that these subdomains are interconnected, ensuring fast equilibration of electron carriers for efficient optimum photosynthesis. Thus, diatoms and plants have converged towards a similar functional distribution of the photosystems although via different thylakoid architectures, which likely evolved independently in the land and the ocean. Phytoplankton and plant plastids have distinct evolutionary origins and membrane organization. Here Flori et al. show that diatom photosynthetic complexes spatially segregate into interconnected subdomains within loose thylakoid stacks enabling fast diffusion of electron carriers and efficient photosynthesis
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Affiliation(s)
- Serena Flori
- Université Grenoble Alpes (UGA), Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, Centre National de la Recherche Scientifique (CNRS), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut National de la Recherche Agronomique (INRA), Institut de Biosciences et Biotechnologie de Grenoble (BIG), CEA-Grenoble, 38000 Grenoble, France
| | - Pierre-Henri Jouneau
- Laboratoire d'Etudes des Matériaux par Microscopie Avancée, Institut Nanosciences et Cryogénie, Service de Physique des Matériaux et Microstructures, CEA-Grenoble, 38000 Grenoble Cédex 9, France
| | - Benjamin Bailleul
- Institut de Biologie Physico-Chimique (IBPC), UMR 7141, CNRS and Université Pierre et Marie Curie (UPMC), 75005 Paris, France
| | - Benoit Gallet
- CNRS, UMR 5075 CNRS, CEA, UGA, Institut de Biologie Structurale, 38000 Grenoble, France
| | - Leandro F Estrozi
- CNRS, UMR 5075 CNRS, CEA, UGA, Institut de Biologie Structurale, 38000 Grenoble, France
| | - Christine Moriscot
- CNRS, UMR 5075 CNRS, CEA, UGA, Institut de Biologie Structurale, 38000 Grenoble, France
| | - Olivier Bastien
- Université Grenoble Alpes (UGA), Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, Centre National de la Recherche Scientifique (CNRS), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut National de la Recherche Agronomique (INRA), Institut de Biosciences et Biotechnologie de Grenoble (BIG), CEA-Grenoble, 38000 Grenoble, France
| | - Simona Eicke
- Plant Biochemistry, Department of Biology, ETH Zurich, CH-8092 Zürich, Switzerland
| | - Alexander Schober
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | | | - Eric Maréchal
- Université Grenoble Alpes (UGA), Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, Centre National de la Recherche Scientifique (CNRS), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut National de la Recherche Agronomique (INRA), Institut de Biosciences et Biotechnologie de Grenoble (BIG), CEA-Grenoble, 38000 Grenoble, France
| | - Peter G Kroth
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Dimitris Petroutsos
- Université Grenoble Alpes (UGA), Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, Centre National de la Recherche Scientifique (CNRS), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut National de la Recherche Agronomique (INRA), Institut de Biosciences et Biotechnologie de Grenoble (BIG), CEA-Grenoble, 38000 Grenoble, France
| | - Samuel Zeeman
- Plant Biochemistry, Department of Biology, ETH Zurich, CH-8092 Zürich, Switzerland
| | - Cécile Breyton
- CNRS, UMR 5075 CNRS, CEA, UGA, Institut de Biologie Structurale, 38000 Grenoble, France
| | - Guy Schoehn
- CNRS, UMR 5075 CNRS, CEA, UGA, Institut de Biologie Structurale, 38000 Grenoble, France
| | - Denis Falconet
- Université Grenoble Alpes (UGA), Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, Centre National de la Recherche Scientifique (CNRS), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut National de la Recherche Agronomique (INRA), Institut de Biosciences et Biotechnologie de Grenoble (BIG), CEA-Grenoble, 38000 Grenoble, France
| | - Giovanni Finazzi
- Université Grenoble Alpes (UGA), Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, Centre National de la Recherche Scientifique (CNRS), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut National de la Recherche Agronomique (INRA), Institut de Biosciences et Biotechnologie de Grenoble (BIG), CEA-Grenoble, 38000 Grenoble, France
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Differential Impacts of Land-Based Sources of Pollution on the Microbiota of Southeast Florida Coral Reefs. Appl Environ Microbiol 2017; 83:AEM.03378-16. [PMID: 28341673 PMCID: PMC5411493 DOI: 10.1128/aem.03378-16] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 02/28/2017] [Indexed: 01/21/2023] Open
Abstract
Coral reefs are dynamic ecosystems known for decades to be endangered due, in large part, to anthropogenic impacts from land-based sources of pollution (LBSP). In this study, we utilized an Illumina-based next-generation sequencing approach to characterize prokaryotic and fungal communities from samples collected off the southeast coast of Florida. Water samples from coastal inlet discharges, oceanic outfalls of municipal wastewater treatment plants, treated wastewater effluent before discharge, open ocean samples, and coral tissue samples (mucus and polyps) were characterized to determine the relationships between microbial communities in these matrices and those in reef water and coral tissues. Significant differences in microbial communities were noted among all sample types but varied between sampling areas. Contamination from outfalls was found to be the greatest potential source of LBSP influencing native microbial community structure among all reef samples, although pollution from inlets was also noted. Notably, reef water and coral tissue communities were found to be more greatly impacted by LBSP at southern reefs, which also experienced the most degradation during the course of the study. The results of this study provide new insights into how microbial communities from LBSP can impact coral reefs in southeast Florida and suggest that wastewater outfalls may have a greater influence on the microbial diversity and structure of these reef communities than do contaminants carried in runoff, although the influences of runoff and coastal inlet discharge on coral reefs are still substantial. IMPORTANCE Coral reefs are known to be endangered due to sewage discharge and to runoff of nutrients, pesticides, and other substances associated with anthropogenic activity. Here, we used next-generation sequencing to characterize the microbial communities of potential contaminant sources in order to determine how environmental discharges of microbiota and their genetic material may influence the microbiomes of coral reef communities and coastal receiving waters. Runoff delivered through inlet discharges impacted coral microbial communities, but impacts from oceanic outfalls carrying treated wastewater were greater. Geographic differences in the degree of impact suggest that coral microbiomes may be influenced by the microbiological quality of treated wastewater.
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Zeaxanthin-dependent nonphotochemical quenching does not occur in photosystem I in the higher plant Arabidopsis thaliana. Proc Natl Acad Sci U S A 2017; 114:4828-4832. [PMID: 28416696 DOI: 10.1073/pnas.1621051114] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nonphotochemical quenching (NPQ) is the process that protects the photosynthetic apparatus of plants and algae from photodamage by dissipating as heat the energy absorbed in excess. Studies on NPQ have almost exclusively focused on photosystem II (PSII), as it was believed that NPQ does not occur in photosystem I (PSI). Recently, Ballottari et al. [Ballottari M, et al. (2014) Proc Natl Acad Sci USA 111:E2431-E2438], analyzing PSI particles isolated from an Arabidopsis thaliana mutant that accumulates zeaxanthin constitutively, have reported that this xanthophyll can efficiently induce chlorophyll fluorescence quenching in PSI. In this work, we have checked the biological relevance of this finding by analyzing WT plants under high-light stress conditions. By performing time-resolved fluorescence measurements on PSI isolated from Arabidopsis thaliana WT in dark-adapted and high-light-stressed (NPQ) states, we find that the fluorescence kinetics of both PSI are nearly identical. To validate this result in vivo, we have measured the kinetics of PSI directly on leaves in unquenched and NPQ states; again, no differences were observed. It is concluded that PSI does not undergo NPQ in biologically relevant conditions in Arabidopsis thaliana The possible role of zeaxanthin in PSI photoprotection is discussed.
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Schumann T, Paul S, Melzer M, Dörmann P, Jahns P. Plant Growth under Natural Light Conditions Provides Highly Flexible Short-Term Acclimation Properties toward High Light Stress. FRONTIERS IN PLANT SCIENCE 2017; 8:681. [PMID: 28515734 PMCID: PMC5413563 DOI: 10.3389/fpls.2017.00681] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 04/13/2017] [Indexed: 05/18/2023]
Abstract
Efficient acclimation to different growth light intensities is essential for plant fitness. So far, most studies on light acclimation have been conducted with plants grown under different constant light regimes, but more recent work indicated that acclimation to fluctuating light or field conditions may result in different physiological properties of plants. Thale cress (Arabidopsis thaliana) was grown under three different constant light intensities (LL: 25 μmol photons m-2 s-1; NL: 100 μmol photons m-2 s-1; HL: 500 μmol photons m-2 s-1) and under natural fluctuating light (NatL) conditions. We performed a thorough characterization of the morphological, physiological, and biochemical properties focusing on photo-protective mechanisms. Our analyses corroborated the known properties of LL, NL, and HL plants. NatL plants, however, were found to combine characteristics of both LL and HL grown plants, leading to efficient and unique light utilization capacities. Strikingly, the high energy dissipation capacity of NatL plants correlated with increased dynamics of thylakoid membrane reorganization upon short-term acclimation to excess light. We conclude that the thylakoid membrane organization and particularly the light-dependent and reversible unstacking of grana membranes likely represent key factors that provide the basis for the high acclimation capacity of NatL grown plants to rapidly changing light intensities.
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Affiliation(s)
- Tobias Schumann
- Plant Biochemistry, Heinrich-Heine-University DüsseldorfDüsseldorf, Germany
| | - Suman Paul
- Department of Plant Physiology, Umeå UniversityUmeå, Sweden
| | - Michael Melzer
- Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK)Seeland, Germany
| | - Peter Dörmann
- Molecular Biotechnology/Biochemistry, Institute of Molecular Physiology and Biotechnology of Plants (IMBIO), Rheinische Friedrich-Wilhelms-University BonnBonn, Germany
| | - Peter Jahns
- Plant Biochemistry, Heinrich-Heine-University DüsseldorfDüsseldorf, Germany
- *Correspondence: Peter Jahns
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Rehman AU, Szabó M, Deák Z, Sass L, Larkum A, Ralph P, Vass I. Symbiodinium sp. cells produce light-induced intra- and extracellular singlet oxygen, which mediates photodamage of the photosynthetic apparatus and has the potential to interact with the animal host in coral symbiosis. THE NEW PHYTOLOGIST 2016; 212:472-484. [PMID: 27321415 DOI: 10.1111/nph.14056] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 05/08/2016] [Indexed: 06/06/2023]
Abstract
Coral bleaching is an important environmental phenomenon, whose mechanism has not yet been clarified. The involvement of reactive oxygen species (ROS) has been implicated, but direct evidence of what species are involved, their location and their mechanisms of production remains unknown. Histidine-mediated chemical trapping and singlet oxygen sensor green (SOSG) were used to detect intra- and extracellular singlet oxygen ((1) O2 ) in Symbiodinium cultures. Inhibition of the Calvin-Benson cycle by thermal stress or high light promotes intracellular (1) O2 formation. Histidine addition, which decreases the amount of intracellular (1) O2 , provides partial protection against photosystem II photoinactivation and chlorophyll (Chl) bleaching. (1) O2 production also occurs in cell-free medium of Symbiodinium cultures, an effect that is enhanced under heat and light stress and can be attributed to the excretion of (1) O2 -sensitizing metabolites from the cells. Confocal microscopy imaging using SOSG showed most extracellular (1) O2 around the cell surface, but it is also produced across the medium distant from the cells. We demonstrate, for the first time, both intra- and extracellular (1) O2 production in Symbiodinium cultures. Intracellular (1) O2 is associated with photosystem II photodamage and pigment bleaching, whereas extracellular (1) O2 has the potential to mediate the breakdown of symbiotic interaction between zooxanthellae and their animal host during coral bleaching.
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Affiliation(s)
- Ateeq Ur Rehman
- Institute of Plant Biology, Biological Research Center of the Hungarian Academy of Sciences, PO Box 521, H-6701, Szeged, Hungary
| | - Milán Szabó
- Plant Functional Biology and Climate Change Cluster (C3), University of Technology Sydney, PO Box 123, Broadway, NSW, 2007, Australia
- Division of Plant Sciences, Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Acton, ACT, 2601, Australia
| | - Zsuzsanna Deák
- Institute of Plant Biology, Biological Research Center of the Hungarian Academy of Sciences, PO Box 521, H-6701, Szeged, Hungary
| | - László Sass
- Institute of Plant Biology, Biological Research Center of the Hungarian Academy of Sciences, PO Box 521, H-6701, Szeged, Hungary
| | - Anthony Larkum
- Plant Functional Biology and Climate Change Cluster (C3), University of Technology Sydney, PO Box 123, Broadway, NSW, 2007, Australia
| | - Peter Ralph
- Plant Functional Biology and Climate Change Cluster (C3), University of Technology Sydney, PO Box 123, Broadway, NSW, 2007, Australia
| | - Imre Vass
- Institute of Plant Biology, Biological Research Center of the Hungarian Academy of Sciences, PO Box 521, H-6701, Szeged, Hungary.
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