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Kim RG, Huang W, Findinier J, Bunbury F, Redekop P, Shrestha R, Grismer TS, Vilarrasa-Blasi J, Jinkerson RE, Fakhimi N, Fauser F, Jonikas MC, Onishi M, Xu SL, Grossman AR. Chloroplast Methyltransferase Homolog RMT2 is Involved in Photosystem I Biogenesis. bioRxiv 2024:2023.12.21.572672. [PMID: 38187728 PMCID: PMC10769443 DOI: 10.1101/2023.12.21.572672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Oxygen (O2), a dominant element in the atmosphere and essential for most life on Earth, is produced by the photosynthetic oxidation of water. However, metabolic activity can cause accumulation of reactive O2 species (ROS) and severe cell damage. To identify and characterize mechanisms enabling cells to cope with ROS, we performed a high-throughput O2 sensitivity screen on a genome-wide insertional mutant library of the unicellular alga Chlamydomonas reinhardtii. This screen led to identification of a gene encoding a protein designated Rubisco methyltransferase 2 (RMT2). Although homologous to methyltransferases, RMT2 has not been experimentally demonstrated to have methyltransferase activity. Furthermore, the rmt2 mutant was not compromised for Rubisco (first enzyme of Calvin-Benson Cycle) levels but did exhibit a marked decrease in accumulation/activity of photosystem I (PSI), which causes light sensitivity, with much less of an impact on other photosynthetic complexes. This mutant also shows increased accumulation of Ycf3 and Ycf4, proteins critical for PSI assembly. Rescue of the mutant phenotype with a wild-type (WT) copy of RMT2 fused to the mNeonGreen fluorophore indicates that the protein localizes to the chloroplast and appears to be enriched in/around the pyrenoid, an intrachloroplast compartment present in many algae that is packed with Rubisco and potentially hypoxic. These results indicate that RMT2 serves an important role in PSI biogenesis which, although still speculative, may be enriched around or within the pyrenoid.
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Affiliation(s)
- Rick G. Kim
- Department of Biosphere Science and Engineering, Carnegie Institution for Science, Stanford, CA 94305, USA
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Weichao Huang
- Department of Biosphere Science and Engineering, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Justin Findinier
- Department of Biosphere Science and Engineering, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Freddy Bunbury
- Department of Biosphere Science and Engineering, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Petra Redekop
- Department of Biosphere Science and Engineering, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Ruben Shrestha
- Department of Biosphere Science and Engineering, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - TaraBryn S Grismer
- Department of Biosphere Science and Engineering, Carnegie Institution for Science, Stanford, CA 94305, USA
| | | | - Robert E. Jinkerson
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA
| | - Neda Fakhimi
- Department of Biosphere Science and Engineering, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Friedrich Fauser
- Department of Biosphere Science and Engineering, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Martin C. Jonikas
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540, USA
| | - Masayuki Onishi
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Shou-Ling Xu
- Department of Biosphere Science and Engineering, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Arthur R. Grossman
- Department of Biosphere Science and Engineering, Carnegie Institution for Science, Stanford, CA 94305, USA
- Department of Biology, Stanford University, Stanford, CA 94305, USA
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Saroussi S, Redekop P, Karns DAJ, Thomas DC, Wittkopp TM, Posewitz MC, Grossman AR. Restricting electron flow at cytochrome b6f when downstream electron acceptors are severely limited. Plant Physiol 2023; 192:789-804. [PMID: 36960590 PMCID: PMC10231464 DOI: 10.1093/plphys/kiad185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 06/01/2023]
Abstract
Photosynthetic organisms frequently experience abiotic stress that restricts their growth and development. Under such circumstances, most absorbed solar energy cannot be used for CO2 fixation and can cause the photoproduction of reactive oxygen species (ROS) that can damage the photosynthetic reaction centers of PSI and PSII, resulting in a decline in primary productivity. This work describes a biological "switch" in the green alga Chlamydomonas reinhardtii that reversibly restricts photosynthetic electron transport (PET) at the cytochrome b6f (Cyt b6f) complex when the capacity for accepting electrons downstream of PSI is severely limited. We specifically show this restriction in STARCHLESS6 (sta6) mutant cells, which cannot synthesize starch when they are limited for nitrogen (growth inhibition) and subjected to a dark-to-light transition. This restriction represents a form of photosynthetic control that causes diminished electron flow to PSI and thereby prevents PSI photodamage but does not appear to rely on a ΔpH. Furthermore, when electron flow is restricted, the plastid alternative oxidase (PTOX) becomes active, functioning as an electron valve that dissipates some excitation energy absorbed by PSII and allows the formation of a proton motive force (PMF) that would drive some ATP production (potentially sustaining PSII repair and nonphotochemical quenching [NPQ]). The restriction at the Cyt b6f complex can be gradually relieved with continued illumination. This study provides insights into how PET responds to a marked reduction in availability of downstream electron acceptors and the protective mechanisms involved.
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Affiliation(s)
- Shai Saroussi
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Petra Redekop
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Devin A J Karns
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Dylan C Thomas
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Tyler M Wittkopp
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Matthew C Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Arthur R Grossman
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
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3
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Águila Ruiz-Sola M, Flori S, Yuan Y, Villain G, Sanz-Luque E, Redekop P, Tokutsu R, Küken A, Tsichla A, Kepesidis G, Allorent G, Arend M, Iacono F, Finazzi G, Hippler M, Nikoloski Z, Minagawa J, Grossman AR, Petroutsos D. Light-independent regulation of algal photoprotection by CO 2 availability. Nat Commun 2023; 14:1977. [PMID: 37031262 PMCID: PMC10082802 DOI: 10.1038/s41467-023-37800-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 03/30/2023] [Indexed: 04/10/2023] Open
Abstract
Photosynthetic algae have evolved mechanisms to cope with suboptimal light and CO2 conditions. When light energy exceeds CO2 fixation capacity, Chlamydomonas reinhardtii activates photoprotection, mediated by LHCSR1/3 and PSBS, and the CO2 Concentrating Mechanism (CCM). How light and CO2 signals converge to regulate these processes remains unclear. Here, we show that excess light activates photoprotection- and CCM-related genes by altering intracellular CO2 concentrations and that depletion of CO2 drives these responses, even in total darkness. High CO2 levels, derived from respiration or impaired photosynthetic fixation, repress LHCSR3/CCM genes while stabilizing the LHCSR1 protein. Finally, we show that the CCM regulator CIA5 also regulates photoprotection, controlling LHCSR3 and PSBS transcript accumulation while inhibiting LHCSR1 protein accumulation. This work has allowed us to dissect the effect of CO2 and light on CCM and photoprotection, demonstrating that light often indirectly affects these processes by impacting intracellular CO2 levels.
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Affiliation(s)
- M Águila Ruiz-Sola
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG-LPCV, 38000, Grenoble, France
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Sevilla, Spain
| | - Serena Flori
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG-LPCV, 38000, Grenoble, France
| | - Yizhong Yuan
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG-LPCV, 38000, Grenoble, France
| | - Gaelle Villain
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG-LPCV, 38000, Grenoble, France
| | - Emanuel Sanz-Luque
- The Carnegie Institution for Science, Department of Plant Biology, Stanford, CA, 94305, USA
- University of Cordoba, Department of Biochemistry and Molecular Biology, Cordoba, Spain
| | - Petra Redekop
- The Carnegie Institution for Science, Department of Plant Biology, Stanford, CA, 94305, USA
| | - Ryutaro Tokutsu
- Division of Environmental photobiology, National Institute for Basic Biology (NIBB), Nishigonaka 38, Myodaiji, Okazaki, 444-8585, Japan
| | - Anika Küken
- Bioinformatics Group, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
- Max-Planck-Institute of Molecular Plant Physiology, Potsdam, Golm, Germany
| | - Angeliki Tsichla
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG-LPCV, 38000, Grenoble, France
| | - Georgios Kepesidis
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG-LPCV, 38000, Grenoble, France
| | - Guillaume Allorent
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG-LPCV, 38000, Grenoble, France
| | - Marius Arend
- Bioinformatics Group, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
- Max-Planck-Institute of Molecular Plant Physiology, Potsdam, Golm, Germany
| | - Fabrizio Iacono
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG-LPCV, 38000, Grenoble, France
| | - Giovanni Finazzi
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG-LPCV, 38000, Grenoble, France
| | - Michael Hippler
- Institute of Plant Biology and Biotechnology, Westfälische Wilhelms Universität, 48143, Münster, Germany
| | - Zoran Nikoloski
- Bioinformatics Group, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
- Max-Planck-Institute of Molecular Plant Physiology, Potsdam, Golm, Germany
| | - Jun Minagawa
- Division of Environmental photobiology, National Institute for Basic Biology (NIBB), Nishigonaka 38, Myodaiji, Okazaki, 444-8585, Japan
| | - Arthur R Grossman
- The Carnegie Institution for Science, Department of Plant Biology, Stanford, CA, 94305, USA
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Huang W, Krishnan A, Plett A, Meagher M, Linka N, Wang Y, Ren B, Findinier J, Redekop P, Fakhimi N, Kim RG, Karns DA, Boyle N, Posewitz MC, Grossman AR. Chlamydomonas mutants lacking chloroplast TRIOSE PHOSPHATE TRANSPORTER3 are metabolically compromised and light-sensitive. Plant Cell 2023:koad095. [PMID: 36970811 DOI: 10.1093/plcell/koad095] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 03/08/2023] [Accepted: 03/23/2023] [Indexed: 06/18/2023]
Abstract
Modulation of photoassimilate export from the chloroplast is essential for controlling the distribution of fixed carbon in the cell and maintaining optimum photosynthetic rates. In this study we identified chloroplast TRIOSE PHOSPHATE/PHOSPHATE TRANSLOCATOR2 (CreTPT2) and CreTPT3 in the green alga Chlamydomonas (Chlamydomonas reinhardtii), which exhibit similar substrate specificities but whose encoding genes are differentially expressed over the diurnal cycle. We focused mostly on CreTPT3 because of its high level of expression and the severe phenotype exhibited by tpt3 relative to tpt2 mutants. Null mutants for CreTPT3 had a pleiotropic phenotype that affected growth, photosynthetic activities, metabolite profiles, carbon partitioning, and organelle-specific accumulation of H2O2. These analyses demonstrated that CreTPT3 is a dominant conduit on the chloroplast envelope for the transport of photoassimilates. In addition, CreTPT3 can serve as a safety valve that moves excess reductant out of the chloroplast and appears to be essential for preventing cells from experiencing oxidative stress and accumulating reactive oxygen species, even under low/moderate light intensities. Finally, our studies indicate subfunctionalization of the CreTPT transporters and suggest that there are differences in managing the export of photoassimilates from the chloroplasts of Chlamydomonas and vascular plants.
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Affiliation(s)
- Weichao Huang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Anagha Krishnan
- Department of Chemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Anastasija Plett
- Institute of Plant Biochemistry, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Michelle Meagher
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | - Nicole Linka
- Institute of Plant Biochemistry, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Yongsheng Wang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
- School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Bijie Ren
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Justin Findinier
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Petra Redekop
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Neda Fakhimi
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Rick G Kim
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Devin A Karns
- Department of Chemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Nanette Boyle
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | - Matthew C Posewitz
- Department of Chemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Arthur R Grossman
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
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5
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Redekop P, Sanz-Luque E, Yuan Y, Villain G, Petroutsos D, Grossman AR. Transcriptional regulation of photoprotection in dark-to-light transition-More than just a matter of excess light energy. Sci Adv 2022; 8:eabn1832. [PMID: 35658034 PMCID: PMC9166400 DOI: 10.1126/sciadv.abn1832] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 04/18/2022] [Indexed: 05/22/2023]
Abstract
In nature, photosynthetic organisms are exposed to different light spectra and intensities depending on the time of day and atmospheric and environmental conditions. When photosynthetic cells absorb excess light, they induce nonphotochemical quenching to avoid photodamage and trigger expression of "photoprotective" genes. In this work, we used the green alga Chlamydomonas reinhardtii to assess the impact of light intensity, light quality, photosynthetic electron transport, and carbon dioxide on induction of the photoprotective genes (LHCSR1, LHCSR3, and PSBS) during dark-to-light transitions. Induction (mRNA accumulation) occurred at very low light intensity and was independently modulated by blue and ultraviolet B radiation through specific photoreceptors; only LHCSR3 was strongly controlled by carbon dioxide levels through a putative enhancer function of CIA5, a transcription factor that controls genes of the carbon concentrating mechanism. We propose a model that integrates inputs of independent signaling pathways and how they may help the cells anticipate diel conditions and survive in a dynamic light environment.
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Affiliation(s)
- Petra Redekop
- Department of Plant Biology, The Carnegie Institution for Science, 260 Panama St, Stanford, CA 94305, USA
- Corresponding author. (E.S.-L.); (P.R.)
| | - Emanuel Sanz-Luque
- Department of Plant Biology, The Carnegie Institution for Science, 260 Panama St, Stanford, CA 94305, USA
- Department of Biochemistry and Molecular Biology, University of Cordoba, 14071 Cordoba, Spain
- Corresponding author. (E.S.-L.); (P.R.)
| | - Yizhong Yuan
- Université Grenoble Alpes, CNRS, CEA, INRAe, IRIG-LPCV, 38000 Grenoble, France
| | - Gaelle Villain
- Université Grenoble Alpes, CNRS, CEA, INRAe, IRIG-LPCV, 38000 Grenoble, France
| | - Dimitris Petroutsos
- Université Grenoble Alpes, CNRS, CEA, INRAe, IRIG-LPCV, 38000 Grenoble, France
| | - Arthur R. Grossman
- Department of Plant Biology, The Carnegie Institution for Science, 260 Panama St, Stanford, CA 94305, USA
- Department of Biology, Stanford University, Stanford, CA 94305, USA
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6
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Redekop P, Rothhausen N, Rothhausen N, Melzer M, Mosebach L, Dülger E, Bovdilova A, Caffarri S, Hippler M, Jahns P. PsbS contributes to photoprotection in Chlamydomonas reinhardtii independently of energy dissipation. Biochimica et Biophysica Acta (BBA) - Bioenergetics 2020; 1861:148183. [DOI: 10.1016/j.bbabio.2020.148183] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/19/2020] [Accepted: 03/09/2020] [Indexed: 02/06/2023]
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Correa-Galvis V, Redekop P, Guan K, Griess A, Truong TB, Wakao S, Niyogi KK, Jahns P. Photosystem II Subunit PsbS Is Involved in the Induction of LHCSR Protein-dependent Energy Dissipation in Chlamydomonas reinhardtii. J Biol Chem 2016; 291:17478-87. [PMID: 27358399 DOI: 10.1074/jbc.m116.737312] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Indexed: 12/19/2022] Open
Abstract
Non-photochemical quenching of excess excitation energy is an important photoprotective mechanism in photosynthetic organisms. In Arabidopsis thaliana, a high quenching capacity is constitutively present and depends on the PsbS protein. In the green alga Chlamydomonas reinhardtii, non-photochemical quenching becomes activated upon high light acclimation and requires the accumulation of light harvesting complex stress-related (LHCSR) proteins. Expression of the PsbS protein in C. reinhardtii has not been reported yet. Here, we show that PsbS is a light-induced protein in C. reinhardtii, whose accumulation under high light is further controlled by CO2 availability. PsbS accumulated after several hours of high light illumination at low CO2 At high CO2, however, PsbS was only transiently expressed under high light and was degraded after 1 h of high light exposure. PsbS accumulation correlated with an enhanced non-photochemical quenching capacity in high light-acclimated cells grown at low CO2 However, PsbS could not compensate for the function of LHCSR in an LHCSR-deficient mutant. Knockdown of PsbS accumulation led to reduction of both non-photochemical quenching capacity and LHCSR3 accumulation. Our data suggest that PsbS is essential for the activation of non-photochemical quenching in C. reinhardtii, possibly by promoting conformational changes required for activation of LHCSR3-dependent quenching in the antenna of photosystem II.
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Affiliation(s)
- Viviana Correa-Galvis
- From the Plant Biochemistry, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Petra Redekop
- From the Plant Biochemistry, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Katharine Guan
- Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, and
| | - Annika Griess
- From the Plant Biochemistry, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Thuy B Truong
- Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, and
| | - Setsuko Wakao
- Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, and
| | - Krishna K Niyogi
- Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, and Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Peter Jahns
- From the Plant Biochemistry, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany,
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