51
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Mungpakdee S, Shinzato C, Takeuchi T, Kawashima T, Koyanagi R, Hisata K, Tanaka M, Goto H, Fujie M, Lin S, Satoh N, Shoguchi E. Massive gene transfer and extensive RNA editing of a symbiotic dinoflagellate plastid genome. Genome Biol Evol 2014; 6:1408-22. [PMID: 24881086 PMCID: PMC4079212 DOI: 10.1093/gbe/evu109] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Genome sequencing of Symbiodinium minutum revealed that 95 of 109 plastid-associated genes have been transferred to the nuclear genome and subsequently expanded by gene duplication. Only 14 genes remain in plastids and occur as DNA minicircles. Each minicircle (1.8–3.3 kb) contains one gene and a conserved noncoding region containing putative promoters and RNA-binding sites. Nine types of RNA editing, including a novel G/U type, were discovered in minicircle transcripts but not in genes transferred to the nucleus. In contrast to DNA editing sites in dinoflagellate mitochondria, which tend to be highly conserved across all taxa, editing sites employed in DNA minicircles are highly variable from species to species. Editing is crucial for core photosystem protein function. It restores evolutionarily conserved amino acids and increases peptidyl hydropathy. It also increases protein plasticity necessary to initiate photosystem complex assembly.
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Affiliation(s)
- Sutada Mungpakdee
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Japan
| | - Chuya Shinzato
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Japan
| | - Takeshi Takeuchi
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Japan
| | - Takeshi Kawashima
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Japan
| | - Ryo Koyanagi
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, JapanDNA Sequencing Section, Okinawa Institute of Science and Technology Graduate University, Japan
| | - Kanako Hisata
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Japan
| | - Makiko Tanaka
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Japan
| | - Hiroki Goto
- DNA Sequencing Section, Okinawa Institute of Science and Technology Graduate University, Japan
| | - Manabu Fujie
- DNA Sequencing Section, Okinawa Institute of Science and Technology Graduate University, Japan
| | - Senjie Lin
- Department of Marine Sciences, University of Connecticut
| | - Nori Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Japan
| | - Eiichi Shoguchi
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Japan
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Schöttler MA, Tóth SZ. Photosynthetic complex stoichiometry dynamics in higher plants: environmental acclimation and photosynthetic flux control. FRONTIERS IN PLANT SCIENCE 2014; 5:188. [PMID: 24860580 PMCID: PMC4026699 DOI: 10.3389/fpls.2014.00188] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 04/22/2014] [Indexed: 05/02/2023]
Abstract
The composition of the photosynthetic apparatus of higher plants is dynamically adjusted to long-term changes in environmental conditions such as growth light intensity and light quality, and to changing metabolic demands for ATP and NADPH imposed by stresses and leaf aging. By changing photosynthetic complex stoichiometry, a long-term imbalance between the photosynthetic production of ATP and NADPH and their metabolic consumption is avoided, and cytotoxic side reactions are minimized. Otherwise, an excess capacity of the light reactions, relative to the demands of primary metabolism, could result in a disturbance of cellular redox homeostasis and an increased production of reactive oxygen species, leading to the destruction of the photosynthetic apparatus and the initiation of cell death programs. In this review, changes of the abundances of the different constituents of the photosynthetic apparatus in response to environmental conditions and during leaf ontogenesis are summarized. The contributions of the different photosynthetic complexes to photosynthetic flux control and the regulation of electron transport are discussed.
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Affiliation(s)
- Mark A. Schöttler
- Max Planck Institute of Molecular Plant PhysiologyPotsdam-Golm, Germany
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53
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Heyneke E, Luschin-Ebengreuth N, Krajcer I, Wolkinger V, Müller M, Zechmann B. Dynamic compartment specific changes in glutathione and ascorbate levels in Arabidopsis plants exposed to different light intensities. BMC PLANT BIOLOGY 2013; 13:104. [PMID: 23865417 PMCID: PMC3728233 DOI: 10.1186/1471-2229-13-104] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 07/16/2013] [Indexed: 05/03/2023]
Abstract
BACKGROUND Excess light conditions induce the generation of reactive oxygen species (ROS) directly in the chloroplasts but also cause an accumulation and production of ROS in peroxisomes, cytosol and vacuoles. Antioxidants such as ascorbate and glutathione occur in all cell compartments where they detoxify ROS. In this study compartment specific changes in antioxidant levels and related enzymes were monitored among Arabidopsis wildtype plants and ascorbate and glutathione deficient mutants (vtc2-1 and pad2-1, respectively) exposed to different light intensities (50, 150 which was considered as control condition, 300, 700 and 1,500 μmol m(-2) s(-1)) for 4 h and 14 d. RESULTS The results revealed that wildtype plants reacted to short term exposure to excess light conditions with the accumulation of ascorbate and glutathione in chloroplasts, peroxisomes and the cytosol and an increased activity of catalase in the leaves. Long term exposure led to an accumulation of ascorbate and glutathione mainly in chloroplasts. In wildtype plants an accumulation of ascorbate and hydrogen peroxide (H2O2) could be observed in vacuoles when exposed to high light conditions. The pad2-1 mutant reacted to long term excess light exposure with an accumulation of ascorbate in peroxisomes whereas the vtc2-1 mutant reacted with an accumulation of glutathione in the chloroplasts (relative to the wildtype) and nuclei during long term high light conditions indicating an important role of these antioxidants in these cell compartments for the protection of the mutants against high light stress. CONCLUSION The results obtained in this study demonstrate that the accumulation of ascorbate and glutathione in chloroplasts, peroxisomes and the cytosol is an important reaction of plants to short term high light stress. The accumulation of ascorbate and H2O2 along the tonoplast and in vacuoles during these conditions indicates an important route for H2O2 detoxification under these conditions.
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Affiliation(s)
- Elmien Heyneke
- Department of Lothar Willmitzer, Max-Planck-Institute of Molecular Plant Physiology, Golm, 14476, Germany
| | - Nora Luschin-Ebengreuth
- Institute for Electron Microscopy and Fine Structure Research, Graz University of Technology, Steyrergasse 17, Graz, 8010, Austria
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
| | - Iztok Krajcer
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
| | - Volker Wolkinger
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
| | - Maria Müller
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
| | - Bernd Zechmann
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
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Chi W, Ma J, Zhang L. Regulatory factors for the assembly of thylakoid membrane protein complexes. Philos Trans R Soc Lond B Biol Sci 2013; 367:3420-9. [PMID: 23148269 DOI: 10.1098/rstb.2012.0065] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Major multi-protein photosynthetic complexes, located in thylakoid membranes, are responsible for the capture of light and its conversion into chemical energy in oxygenic photosynthetic organisms. Although the structures and functions of these photosynthetic complexes have been explored, the molecular mechanisms underlying their assembly remain elusive. In this review, we summarize current knowledge of the regulatory components involved in the assembly of thylakoid membrane protein complexes in photosynthetic organisms. Many of the known regulatory factors are conserved between prokaryotes and eukaryotes, whereas others appear to be newly evolved or to have expanded predominantly in eukaryotes. Their specific features and fundamental differences in cyanobacteria, green algae and land plants are discussed.
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Affiliation(s)
- Wei Chi
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, People's Republic of China
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55
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Tikkanen M, Grieco M, Nurmi M, Rantala M, Suorsa M, Aro EM. Regulation of the photosynthetic apparatus under fluctuating growth light. Philos Trans R Soc Lond B Biol Sci 2013; 367:3486-93. [PMID: 23148275 DOI: 10.1098/rstb.2012.0067] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Safe and efficient conversion of solar energy to metabolic energy by plants is based on tightly inter-regulated transfer of excitation energy, electrons and protons in the photosynthetic machinery according to the availability of light energy, as well as the needs and restrictions of metabolism itself. Plants have mechanisms to enhance the capture of energy when light is limited for growth and development. Also, when energy is in excess, the photosynthetic machinery slows down the electron transfer reactions in order to prevent the production of reactive oxygen species and the consequent damage of the photosynthetic machinery. In this opinion paper, we present a partially hypothetical scheme describing how the photosynthetic machinery controls the flow of energy and electrons in order to enable the maintenance of photosynthetic activity in nature under continual fluctuations in white light intensity. We discuss the roles of light-harvesting II protein phosphorylation, thermal dissipation of excess energy and the control of electron transfer by cytochrome b(6)f, and the role of dynamically regulated turnover of photosystem II in the maintenance of the photosynthetic machinery. We present a new hypothesis suggesting that most of the regulation in the thylakoid membrane occurs in order to prevent oxidative damage of photosystem I.
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Affiliation(s)
- Mikko Tikkanen
- Molecular Plant Biology, Department of Biochemistry and Food Chemistry, University of Turku, Turku, Finland
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56
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Shibata Y, Katoh W, Tahara Y. Study of cell-differentiation and assembly of photosynthetic proteins during greening of etiolated Zea mays leaves using confocal fluorescence microspectroscopy at liquid-nitrogen temperature. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:520-8. [DOI: 10.1016/j.bbabio.2013.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 01/31/2013] [Accepted: 02/06/2013] [Indexed: 10/27/2022]
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Lyska D, Meierhoff K, Westhoff P. How to build functional thylakoid membranes: from plastid transcription to protein complex assembly. PLANTA 2013; 237:413-28. [PMID: 22976450 PMCID: PMC3555230 DOI: 10.1007/s00425-012-1752-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 08/10/2012] [Indexed: 05/06/2023]
Abstract
Chloroplasts are the endosymbiotic descendants of cyanobacterium-like prokaryotes. Present genomes of plant and green algae chloroplasts (plastomes) contain ~100 genes mainly encoding for their transcription-/translation-machinery, subunits of the thylakoid membrane complexes (photosystems II and I, cytochrome b (6) f, ATP synthase), and the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. Nevertheless, proteomic studies have identified several thousand proteins in chloroplasts indicating that the majority of the plastid proteome is not encoded by the plastome. Indeed, plastid and host cell genomes have been massively rearranged in the course of their co-evolution, mainly through gene loss, horizontal gene transfer from the cyanobacterium/chloroplast to the nucleus of the host cell, and the emergence of new nuclear genes. Besides structural components of thylakoid membrane complexes and other (enzymatic) complexes, the nucleus provides essential factors that are involved in a variety of processes inside the chloroplast, like gene expression (transcription, RNA-maturation and translation), complex assembly, and protein import. Here, we provide an overview on regulatory factors that have been described and characterized in the past years, putting emphasis on mechanisms regulating the expression and assembly of the photosynthetic thylakoid membrane complexes.
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Affiliation(s)
- Dagmar Lyska
- Entwicklungs- und Molekularbiologie der Pflanzen, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, Düsseldorf, Germany.
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Dall'Osto L, Piques M, Ronzani M, Molesini B, Alboresi A, Cazzaniga S, Bassi R. The Arabidopsis nox mutant lacking carotene hydroxylase activity reveals a critical role for xanthophylls in photosystem I biogenesis. THE PLANT CELL 2013; 25:591-608. [PMID: 23396829 PMCID: PMC3608780 DOI: 10.1105/tpc.112.108621] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Revised: 01/15/2013] [Accepted: 01/18/2013] [Indexed: 05/05/2023]
Abstract
Carotenes, and their oxygenated derivatives xanthophylls, are essential components of the photosynthetic apparatus. They contribute to the assembly of photosynthetic complexes and participate in light absorption and chloroplast photoprotection. Here, we studied the role of xanthophylls, as distinct from that of carotenes, by characterizing a no xanthophylls (nox) mutant of Arabidopsis thaliana, which was obtained by combining mutations targeting the four carotenoid hydroxylase genes. nox plants retained α- and β-carotenes but were devoid in xanthophylls. The phenotype included depletion of light-harvesting complex (LHC) subunits and impairment of nonphotochemical quenching, two effects consistent with the location of xanthophylls in photosystem II antenna, but also a decreased efficiency of photosynthetic electron transfer, photosensitivity, and lethality in soil. Biochemical analysis revealed that the nox mutant was specifically depleted in photosystem I function due to a severe deficiency in PsaA/B subunits. While the stationary level of psaA/B transcripts showed no major differences between genotypes, the stability of newly synthesized PsaA/B proteins was decreased and translation of psaA/B mRNA was impaired in nox with respect to wild-type plants. We conclude that xanthophylls, besides their role in photoprotection and LHC assembly, are also needed for photosystem I core translation and stability, thus making these compounds indispensable for autotrophic growth.
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Affiliation(s)
- Luca Dall'Osto
- Dipartimento di Biotecnologie, Università di Verona, 37134 Verona, Italy.
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59
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Hanson MR, Gray BN, Ahner BA. Chloroplast transformation for engineering of photosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:731-42. [PMID: 23162121 DOI: 10.1093/jxb/ers325] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Many efforts are underway to engineer improvements in photosynthesis to meet the challenges of increasing demands for food and fuel in rapidly changing environmental conditions. Various transgenes have been introduced into either the nuclear or plastid genomes in attempts to increase photosynthetic efficiency. We examine the current knowledge of the critical features that affect levels of expression of plastid transgenes and protein accumulation in transplastomic plants, such as promoters, 5' and 3' untranslated regions, RNA-processing sites, translation signals and amino acid sequences that affect protein turnover. We review the prior attempts to manipulate the properties of ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) through plastid transformation. We illustrate how plastid operons could be created for expression of the multiple genes needed to introduce new pathways or enzymes to enhance photosynthetic rates or reduce photorespiration. We describe here the past accomplishments and future prospects for manipulating plant enzymes and pathways to enhance carbon assimilation through plastid transformation.
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Affiliation(s)
- Maureen R Hanson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
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60
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Nickelsen J, Zerges W. Thylakoid biogenesis has joined the new era of bacterial cell biology. FRONTIERS IN PLANT SCIENCE 2013; 4:458. [PMID: 24312109 PMCID: PMC3826073 DOI: 10.3389/fpls.2013.00458] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 10/25/2013] [Indexed: 05/20/2023]
Affiliation(s)
- Jörg Nickelsen
- Molecular Plant Sciences, Ludwig-Maximillians-UniversityPlanegg-Martinsried, Germany
- *Correspondence: ;
| | - William Zerges
- Biology Department, Concordia UniversityMontreal, QC, Canada
- *Correspondence: ;
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61
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Nickelsen J, Rengstl B. Photosystem II assembly: from cyanobacteria to plants. ANNUAL REVIEW OF PLANT BIOLOGY 2013; 64:609-35. [PMID: 23451783 DOI: 10.1146/annurev-arplant-050312-120124] [Citation(s) in RCA: 220] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Photosystem II (PSII) is an integral-membrane, multisubunit complex that initiates electron flow in oxygenic photosynthesis. The biogenesis of this complex machine involves the concerted assembly of at least 20 different polypeptides as well as the incorporation of a variety of inorganic and organic cofactors. Many factors have recently been identified that constitute an integrative network mediating the stepwise assembly of PSII components. One recurring theme is the subcellular organization of the assembly process in specialized membranes that form distinct biogenesis centers. Here, we review our current knowledge of the molecular components and events involved in PSII assembly and their high degree of evolutionary conservation.
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Affiliation(s)
- Jörg Nickelsen
- Molekulare Pflanzenwissenschaften, Biozentrum Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany.
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62
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Suorsa M, Grieco M, Järvi S, Gollan PJ, Kangasjärvi S, Tikkanen M, Aro EM. PGR5 ensures photosynthetic control to safeguard photosystem I under fluctuating light conditions. PLANT SIGNALING & BEHAVIOR 2013; 8:e22741. [PMID: 23221748 PMCID: PMC3745580 DOI: 10.4161/psb.22741] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 11/01/2012] [Indexed: 05/19/2023]
Abstract
In a plant's natural environment, the intensity of light can change rapidly due to sunflecks, cloudiness and intermittent shading. Fluctuations between high and low illumination phases expose the photosynthetic machinery to rapidly changing signals that can be overlapping or contradictory, and accordingly plants have developed astute acclimation strategies to maintain optimal photosynthetic performance in these conditions. Continuous exposure to high light induces an array of protective mechanisms at anatomical, chemical and molecular levels, but when high light phases are short, such as under fluctuating light conditions, the protective strategies that afford protection to constant high light are not employed by plants. One mechanism that is engaged under both constant and fluctuating high light is the photosynthetic control of the Cyt b 6f complex, which prevents hyper-reduction of the electron transfer chain in order to protect PSI from photodamage. The PGR5 protein was recently shown to play an indispensable role in this protective mechanism. This review revisits the findings of earlier studies into photosynthetic control and places PGR5 within the broader context of photoprotection and light acclimation strategies.
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64
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Liu J, Yang H, Lu Q, Wen X, Chen F, Peng L, Zhang L, Lu C. PsbP-domain protein1, a nuclear-encoded thylakoid lumenal protein, is essential for photosystem I assembly in Arabidopsis. THE PLANT CELL 2012; 24:4992-5006. [PMID: 23221595 PMCID: PMC3556971 DOI: 10.1105/tpc.112.106542] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
To gain insights into the molecular details of photosystem I (PSI) biogenesis, we characterized the PsbP-domain protein1 (ppd1) mutant of Arabidopsis thaliana that specifically lacks PSI activity. Deletion of PPD1 results in an inability of the mutant to grow photoautotrophically and a specific loss of the stable PSI complex. Unaltered transcription and translation of plastid-encoded PSI genes indicate that PPD1 acts at the posttranslational level. In vivo protein labeling experiments reveal that the rate of synthesis of PSI reaction center proteins PsaA/B in ppd1 is comparable to that of wild-type plants, whereas the rate of turnover of PsaA/B proteins is higher in ppd1 than in wild-type plants. With increasing leaf age, PPD1 content decreases considerably, while PSI content remains constant. PPD1 is a nuclear-encoded thylakoid lumenal protein and is associated with PSI but is not an integral subunit of PSI. Biochemical and molecular analyses reveal that PPD1 interacts directly and specifically with PsaB and PsaA. Yeast two-hybrid experiments show that PPD1 interacts with some lumenal loops of PsaB and PsaA. Our results suggest that PPD1 is a PSI assembly factor that assists the proper folding and integration of PsaB and PsaA into the thylakoid membrane.
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Affiliation(s)
- Jun Liu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huixia Yang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Qingtao Lu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xiaogang Wen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Fan Chen
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Lianwei Peng
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Lixin Zhang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- National Center for Plant Gene Research, Beijing 100093, China
| | - Congming Lu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- National Center for Plant Gene Research, Beijing 100093, China
- Address correspondence to
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Komenda J, Sobotka R, Nixon PJ. Assembling and maintaining the Photosystem II complex in chloroplasts and cyanobacteria. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:245-51. [PMID: 22386092 DOI: 10.1016/j.pbi.2012.01.017] [Citation(s) in RCA: 176] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 01/30/2012] [Accepted: 01/30/2012] [Indexed: 05/20/2023]
Abstract
Plants, algae and cyanobacteria grow because of their ability to use sunlight to extract electrons from water. This vital reaction is catalysed by the Photosystem II (PSII) complex, a large multi-subunit pigment-protein complex embedded in the thylakoid membrane. Recent results show that assembly of PSII occurs in a step-wise fashion in defined regions of the membrane system, involves conserved auxiliary factors and is closely coupled to chlorophyll biosynthesis. PSII is also repaired following damage by light. FtsH proteases play an important role in selectively removing damaged proteins from the complex, both in chloroplasts and cyanobacteria, whilst undamaged subunits and pigments are recycled. The chloroplastic Deg proteases play a supplementary role in PSII repair.
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Affiliation(s)
- Josef Komenda
- Institute of Microbiology, Laboratory of Photosynthesis, Opatovický mlýn, Třeboň, Czech Republic
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Krech K, Ruf S, Masduki FF, Thiele W, Bednarczyk D, Albus CA, Tiller N, Hasse C, Schöttler MA, Bock R. The plastid genome-encoded Ycf4 protein functions as a nonessential assembly factor for photosystem I in higher plants. PLANT PHYSIOLOGY 2012; 159:579-91. [PMID: 22517411 PMCID: PMC3375926 DOI: 10.1104/pp.112.196642] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 04/17/2012] [Indexed: 05/18/2023]
Abstract
Photosystem biogenesis in the thylakoid membrane is a highly complicated process that requires the coordinated assembly of nucleus-encoded and chloroplast-encoded protein subunits as well as the insertion of hundreds of cofactors, such as chromophores (chlorophylls, carotenoids) and iron-sulfur clusters. The molecular details of the assembly process and the identity and functions of the auxiliary factors involved in it are only poorly understood. In this work, we have characterized the chloroplast genome-encoded ycf4 (for hypothetical chloroplast reading frame no. 4) gene, previously shown to encode a protein involved in photosystem I (PSI) biogenesis in the unicellular green alga Chlamydomonas reinhardtii. Using stable transformation of the chloroplast genome, we have generated ycf4 knockout plants in the higher plant tobacco (Nicotiana tabacum). Although these mutants are severely affected in their photosynthetic performance, they are capable of photoautotrophic growth, demonstrating that, different from Chlamydomonas, the ycf4 gene product is not essential for photosynthesis. We further show that ycf4 knockout plants are specifically deficient in PSI accumulation. Unaltered expression of plastid-encoded PSI genes and biochemical analyses suggest a posttranslational action of the Ycf4 protein in the PSI assembly process. With increasing leaf age, the contents of Ycf4 and Y3IP1, another auxiliary factor involved in PSI assembly, decrease strongly, whereas PSI contents remain constant, suggesting that PSI is highly stable and that its biogenesis is restricted to young leaves.
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Affiliation(s)
- Katharina Krech
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | - Stephanie Ruf
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | - Fifi F. Masduki
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | - Wolfram Thiele
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | | | - Christin A. Albus
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | - Nadine Tiller
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | - Claudia Hasse
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | - Mark A. Schöttler
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D–14476 Potsdam-Golm, Germany
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Börner T. Regulation of plant primary metabolism. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:1309-10. [PMID: 21601945 DOI: 10.1016/j.jplph.2011.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/28/2011] [Indexed: 05/30/2023]
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