1
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Krämer C, Boehm CR, Liu J, Ting MKY, Hertle AP, Forner J, Ruf S, Schöttler MA, Zoschke R, Bock R. Removal of the large inverted repeat from the plastid genome reveals gene dosage effects and leads to increased genome copy number. NATURE PLANTS 2024; 10:923-935. [PMID: 38802561 PMCID: PMC11208156 DOI: 10.1038/s41477-024-01709-9] [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: 11/22/2023] [Accepted: 04/24/2024] [Indexed: 05/29/2024]
Abstract
The chloroplast genomes of most plants and algae contain a large inverted repeat (IR) region that separates two single-copy regions and harbours the ribosomal RNA operon. We have addressed the functional importance of the IR region by removing an entire copy of the 25.3-kb IR from the tobacco plastid genome. Using plastid transformation and subsequent selectable marker gene elimination, we precisely excised the IR, thus generating plants with a substantially reduced plastid genome size. We show that the lack of the IR results in a mildly reduced plastid ribosome number, suggesting a gene dosage benefit from the duplicated presence of the ribosomal RNA operon. Moreover, the IR deletion plants contain an increased number of plastid genomes, suggesting that genome copy number is regulated by measuring total plastid DNA content rather than by counting genomes. Together, our findings (1) demonstrate that the IR can enhance the translation capacity of the plastid, (2) reveal the relationship between genome size and genome copy number, and (3) provide a simplified plastid genome structure that will facilitate future synthetic biology applications.
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Affiliation(s)
- Carolin Krämer
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Christian R Boehm
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Jinghan Liu
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | | | - Alexander P Hertle
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Joachim Forner
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Stephanie Ruf
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Mark A Schöttler
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Reimo Zoschke
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany.
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2
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Gu L. Optimizing the electron transport chain to sustainably improve photosynthesis. PLANT PHYSIOLOGY 2023; 193:2398-2412. [PMID: 37671674 PMCID: PMC10663115 DOI: 10.1093/plphys/kiad490] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 07/28/2023] [Accepted: 08/11/2023] [Indexed: 09/07/2023]
Abstract
Genetically improving photosynthesis is a key strategy to boosting crop production to meet the rising demand for food and fuel by a rapidly growing global population in a warming climate. Many components of the photosynthetic apparatus have been targeted for genetic modification for improving photosynthesis. Successful translation of these modifications into increased plant productivity in fluctuating environments will depend on whether the electron transport chain (ETC) can support the increased electron transport rate without risking overreduction and photodamage. At present atmospheric conditions, the ETC appears suboptimal and will likely need to be modified to support proposed photosynthetic improvements and to maintain energy balance. Here, I derive photochemical equations to quantify the transport capacity and the corresponding reduction level based on the kinetics of redox reactions along the ETC. Using these theoretical equations and measurements from diverse C3/C4 species across environments, I identify several strategies that can simultaneously increase the transport capacity and decrease the reduction level of the ETC. These strategies include increasing the abundances of reaction centers, cytochrome b6f complexes, and mobile electron carriers, improving their redox kinetics, and decreasing the fraction of secondary quinone-nonreducing photosystem II reaction centers. I also shed light on several previously unexplained experimental findings regarding the physiological impacts of the abundances of the cytochrome b6f complex and plastoquinone. The model developed, and the insights generated from it facilitate the development of sustainable photosynthetic systems for greater crop yields.
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Affiliation(s)
- Lianhong Gu
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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3
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Vidal‐Meireles A, Kuntam S, Széles E, Tóth D, Neupert J, Bock R, Tóth SZ. The lifetime of the oxygen-evolving complex subunit PSBO depends on light intensity and carbon availability in Chlamydomonas. PLANT, CELL & ENVIRONMENT 2023; 46:422-439. [PMID: 36320098 PMCID: PMC10100022 DOI: 10.1111/pce.14481] [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: 08/22/2022] [Revised: 10/13/2022] [Accepted: 10/14/2022] [Indexed: 06/16/2023]
Abstract
PSBO is essential for the assembly of the oxygen-evolving complex in plants and green algae. Despite its importance, we lack essential information on its lifetime and how it depends on the environmental conditions. We have generated nitrate-inducible PSBO amiRNA lines in the green alga Chlamydomonas reinhardtii. Transgenic strains grew normally under non-inducing conditions, and their photosynthetic performance was comparable to the control strain. Upon induction of the PSBO amiRNA constructs, cell division halted. In acetate-containing medium, cellular PSBO protein levels decreased by 60% within 24 h in the dark, by 75% in moderate light, and in high light, the protein completely degraded. Consequently, the photosynthetic apparatus became strongly damaged, probably due to 'donor-side-induced photoinhibition', and cellular ultrastructure was also severely affected. However, in the absence of acetate during induction, PSBO was remarkably stable at all light intensities and less substantial changes occurred in photosynthesis. Our results demonstrate that the lifetime of PSBO strongly depends on the light intensity and carbon availability, and thus, on the metabolic status of the cells. We also confirm that PSBO is required for photosystem II stability in C. reinhardtii and demonstrate that its specific loss also entails substantial changes in cell morphology and cell cycle.
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Affiliation(s)
- André Vidal‐Meireles
- Laboratory for Molecular Photobioenergetics, Biological Research CentreInstitute of Plant BiologySzegedHungary
- Present address:
Institute of Plant Biology and Biotechnology (IBBP), Westfälische Wilhelms‐Universität Münster (WWU)MünsterGermany
| | - Soujanya Kuntam
- Laboratory for Molecular Photobioenergetics, Biological Research CentreInstitute of Plant BiologySzegedHungary
| | - Eszter Széles
- Laboratory for Molecular Photobioenergetics, Biological Research CentreInstitute of Plant BiologySzegedHungary
- Doctoral School of BiologyUniversity of SzegedSzegedHungary
| | - Dávid Tóth
- Laboratory for Molecular Photobioenergetics, Biological Research CentreInstitute of Plant BiologySzegedHungary
- Doctoral School of BiologyUniversity of SzegedSzegedHungary
| | - Juliane Neupert
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
| | - Ralph Bock
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
| | - Szilvia Z. Tóth
- Laboratory for Molecular Photobioenergetics, Biological Research CentreInstitute of Plant BiologySzegedHungary
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4
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Loiacono FV, Walther D, Seeger S, Thiele W, Gerlach I, Karcher D, Schöttler MA, Zoschke R, Bock R. Emergence of Novel RNA-Editing Sites by Changes in the Binding Affinity of a Conserved PPR Protein. Mol Biol Evol 2022; 39:6760358. [PMID: 36227729 PMCID: PMC9750133 DOI: 10.1093/molbev/msac222] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/23/2022] [Accepted: 10/07/2022] [Indexed: 01/07/2023] Open
Abstract
RNA editing converts cytidines to uridines in plant organellar transcripts. Editing typically restores codons for conserved amino acids. During evolution, specific C-to-U editing sites can be lost from some plant lineages by genomic C-to-T mutations. By contrast, the emergence of novel editing sites is less well documented. Editing sites are recognized by pentatricopeptide repeat (PPR) proteins with high specificity. RNA recognition by PPR proteins is partially predictable, but prediction is often inadequate for PPRs involved in RNA editing. Here we have characterized evolution and recognition of a recently gained editing site. We demonstrate that changes in the RNA recognition motifs that are not explainable with the current PPR code allow an ancient PPR protein, QED1, to uniquely target the ndhB-291 site in Brassicaceae. When expressed in tobacco, the Arabidopsis QED1 edits 33 high-confident off-target sites in chloroplasts and mitochondria causing a spectrum of mutant phenotypes. By manipulating the relative expression levels of QED1 and ndhB-291, we show that the target specificity of the PPR protein depends on the RNA:protein ratio. Finally, our data suggest that the low expression levels of PPR proteins are necessary to ensure the specificity of editing site selection and prevent deleterious off-target editing.
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Affiliation(s)
- F Vanessa Loiacono
- Department of Organelle Biology, Biotechnology and Molecular Ecophysiology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Dirk Walther
- Department of Organelle Biology, Biotechnology and Molecular Ecophysiology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Stefanie Seeger
- Department of Organelle Biology, Biotechnology and Molecular Ecophysiology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Wolfram Thiele
- Department of Organelle Biology, Biotechnology and Molecular Ecophysiology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Ines Gerlach
- Department of Organelle Biology, Biotechnology and Molecular Ecophysiology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Daniel Karcher
- Department of Organelle Biology, Biotechnology and Molecular Ecophysiology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Mark Aurel Schöttler
- Department of Organelle Biology, Biotechnology and Molecular Ecophysiology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Reimo Zoschke
- Department of Organelle Biology, Biotechnology and Molecular Ecophysiology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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5
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Sandoval-Ibáñez O, Rolo D, Ghandour R, Hertle AP, Armarego-Marriott T, Sampathkumar A, Zoschke R, Bock R. De-etiolation-induced protein 1 (DEIP1) mediates assembly of the cytochrome b 6f complex in Arabidopsis. Nat Commun 2022; 13:4045. [PMID: 35831297 PMCID: PMC9279372 DOI: 10.1038/s41467-022-31758-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 07/01/2022] [Indexed: 11/26/2022] Open
Abstract
The conversion of light energy to chemical energy by photosynthesis requires the concerted action of large protein complexes in the thylakoid membrane. Recent work has provided fundamental insights into the three-dimensional structure of these complexes, but how they are assembled from hundreds of parts remains poorly understood. Particularly little is known about the biogenesis of the cytochrome b6f complex (Cytb6f), the redox-coupling complex that interconnects the two photosystems. Here we report the identification of a factor that guides the assembly of Cytb6f in thylakoids of chloroplasts. The protein, DE-ETIOLATION-INDUCED PROTEIN 1 (DEIP1), resides in the thylakoid membrane and is essential for photoautotrophic growth. Knock-out mutants show a specific loss of Cytb6f, and are defective in complex assembly. We demonstrate that DEIP1 interacts with the two cytochrome subunits of the complex, PetA and PetB, and mediates the assembly of intermediates in Cytb6f biogenesis. The identification of DEIP1 provides an entry point into the study of the assembly pathway of a crucial complex in photosynthetic electron transfer. The Cytb6f complex is a multi-subunit enzyme that couples the two photosystems during the light reactions of photosynthesis. Here the authors show that the thylakoid-localized DEIP1 protein interacts with the PetA and PetB subunits, and is essential for Cytb6f complex assembly in Arabidopsis.
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Affiliation(s)
- Omar Sandoval-Ibáñez
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - David Rolo
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Rabea Ghandour
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Alexander P Hertle
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Tegan Armarego-Marriott
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Arun Sampathkumar
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Reimo Zoschke
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany.
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6
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Effect of Elevated Temperature and Excess Light on Photosynthetic Efficiency, Pigments, and Proteins in the Field-Grown Sunflower during Afternoon. HORTICULTURAE 2022. [DOI: 10.3390/horticulturae8050392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study examined the photosynthetic responses of two sunflower hybrids to elevated temperatures and excess light intensity in the flowering stage by measuring the chlorophyll a fluorescence (ChlF) under morning and afternoon field conditions to determine the photosynthetic pigment contents and the relative accumulation of photosynthetic proteins. The morning environmental conditions were considered optimal, while the afternoon was characterised by elevated temperatures and excess light intensity. The minimum fluorescence intensity (F0), the electron-flux-reducing end electron acceptors at the photosystem I acceptor side per reaction centre (RE0/RC), and the D1 protein had significant, high, and positive correlations with the environmental conditions, which indicates that they were the most useful in the sunflower-stress-response research. In hybrid 7, the elevated temperatures and the excess light intensity resulted in the inactivation of the oxygen-evolving complex, which was indicated by the positive L, K, and J steps, the increase in the maximum quantum yield of PSII (TR0/ABS), the decrease in the electron transport further than the primary acceptor QA (ET0/(TR0-ET0)), the reduction in the performance index (PIABS), and the higher relative accumulation of the light-harvesting complex of the photosystem (LHCII). Hybrid 4 had smaller changes in the fluorescence curves in phases O–J and J–I, and especially in steps L, K, J, and I, and a higher PIABS, which indicates a more efficient excitation energy under the unfavourable conditions. As the tested parameters were sensitive enough to determine the significant differences between the sunflower hybrids in their photosynthetic responses to the elevated temperatures and excess light intensity in the flowering stage, they can be considered useful selection criteria. The development of more adaptable sunflower hybrids encourages sustainable sunflower production under stressful growing conditions.
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7
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Oung HMO, Mukhopadhyay R, Svoboda V, Charuvi D, Reich Z, Kirchhoff H. Differential response of the photosynthetic machinery to dehydration in older and younger resurrection plants. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1566-1580. [PMID: 34747457 DOI: 10.1093/jxb/erab485] [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: 08/05/2021] [Accepted: 11/03/2021] [Indexed: 06/13/2023]
Abstract
A group of vascular plants called homoiochlorophyllous resurrection plants evolved unique capabilities to protect their photosynthetic machinery against desiccation-induced damage. This study examined whether the ontogenetic status of the resurrection plant Craterostigma pumilum has an impact on how the plant responds to dehydration at the thylakoid membrane level to prepare cells for the desiccated state. Thus, younger plants (<4 months) were compared with their older (>6 months) counterparts. Ultrastructural analysis provided evidence that younger plants suppressed senescence-like programs that are realized in older plants. During dehydration, older plants degrade specific subunits of the photosynthetic apparatus such as the D1 subunit of PSII and subunits of the cytochrome b6f complex. The latter leads to a controlled down-regulation of linear electron transport. In contrast, younger plants increased photoprotective high-energy quenching mechanisms and maintained a high capability to replace damaged D1 subunits. It follows that depending on the ontogenetic state, either more degradation-based or more photoprotective mechanisms are employed during dehydration of Craterostigma pumilum.
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Affiliation(s)
- Hui Min Olivia Oung
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Roma Mukhopadhyay
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Vaclav Svoboda
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Dana Charuvi
- Institute of Plant Sciences, Agricultural Research Organization - Volcani Institute, Rishon LeZion 7505101, Israel
| | - Ziv Reich
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
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8
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Dong C, Qu G, Guo J, Wei F, Gao S, Sun Z, Jin L, Sun X, Rochaix JD, Miao Y, Wang R. Rational design of geranylgeranyl diphosphate synthase enhances carotenoid production and improves photosynthetic efficiency in Nicotiana tabacum. Sci Bull (Beijing) 2022; 67:315-327. [PMID: 36546080 DOI: 10.1016/j.scib.2021.07.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/01/2021] [Accepted: 06/24/2021] [Indexed: 01/06/2023]
Abstract
Restricted genetic diversity can supply only a limited number of elite genes for modern plant cultivation and transgenesis. In this study, we demonstrate that rational design enables the engineering of geranylgeranyl diphosphate synthase (NtGGPPS), an enzyme of the methylerythritol phosphate pathway (MEP) in the model plant Nicotiana tabacum. As the crucial bottleneck in carotenoid biosynthesis, NtGGPPS1 interacts with phytoene synthase (NtPSY1) to channel GGPP into the production of carotenoids. Loss of this enzyme in the ntggpps1 mutant leads to decreased carotenoid accumulation. With the aim of enhancing NtGGPPS1 activity, we undertook structure-guided rational redesign of its substrate binding pocket in combination with sequence alignment. The activity of the designed NtGGPPS1 (a pentuple mutant of five sites V154A/I161L/F218Y/I209S/V233E, d-NtGGPPS1) was measured by a high-throughput colorimetric assay. d-NtGGPPS1 exhibited significantly higher conversion of IPP and each co-substrate (DMAPP ~1995.5-fold, GPP ~25.9-fold, and FPP ~16.7-fold) for GGPP synthesis compared with wild-type NtGGPPS1. Importantly, the transient and stable expression of d-NtGGPPS1 in the ntggpps1 mutant increased carotenoid levels in leaves, improved photosynthetic efficiency, and increased biomass relative to NtGGPPS1. These findings provide a firm basis for the engineering of GGPPS and will facilitate the development of quality and yield traits. Our results open the door for the structure-guided rational design of elite genes in higher plants.
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Affiliation(s)
- Chen Dong
- Zhengzhou Tobacco Research Institute, Zhengzhou 450001, China; Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475001, China; College of Biological Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Ge Qu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Jinggong Guo
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475001, China
| | - Fang Wei
- School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Shuwen Gao
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475001, China
| | - Zhoutong Sun
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Lifeng Jin
- Zhengzhou Tobacco Research Institute, Zhengzhou 450001, China
| | - Xuwu Sun
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475001, China
| | - Jean-David Rochaix
- Departments of Molecular Biology and Plant Biology, University of Geneva, Geneva 1211, Switzerland
| | - Yuchen Miao
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475001, China.
| | - Ran Wang
- Zhengzhou Tobacco Research Institute, Zhengzhou 450001, China; School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China.
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9
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Romand S, Abdelkefi H, Lecampion C, Belaroussi M, Dussenne M, Ksas B, Citerne S, Caius J, D'Alessandro S, Fakhfakh H, Caffarri S, Havaux M, Field B. A guanosine tetraphosphate (ppGpp) mediated brake on photosynthesis is required for acclimation to nitrogen limitation in Arabidopsis. eLife 2022; 11:e75041. [PMID: 35156611 PMCID: PMC8887892 DOI: 10.7554/elife.75041] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
Abstract
Guanosine pentaphosphate and tetraphosphate (together referred to as ppGpp) are hyperphosphorylated nucleotides found in bacteria and the chloroplasts of plants and algae. In plants and algae artificial ppGpp accumulation can inhibit chloroplast gene expression, and influence photosynthesis, nutrient remobilization, growth, and immunity. However, it is so far unknown whether ppGpp is required for abiotic stress acclimation in plants. Here, we demonstrate that ppGpp biosynthesis is necessary for acclimation to nitrogen starvation in Arabidopsis. We show that ppGpp is required for remodeling the photosynthetic electron transport chain to downregulate photosynthetic activity and for protection against oxidative stress. Furthermore, we demonstrate that ppGpp is required for coupling chloroplastic and nuclear gene expression during nitrogen starvation. Altogether, our work indicates that ppGpp is a pivotal regulator of chloroplast activity for stress acclimation in plants.
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Affiliation(s)
- Shanna Romand
- Aix-Marseille University, CEA, CNRS, BIAM, LGBP TeamMarseilleFrance
| | - Hela Abdelkefi
- Aix-Marseille University, CEA, CNRS, BIAM, LGBP TeamMarseilleFrance
- University of Tunis El Manar, Faculty of Sciences of Tunis, Laboratory of Molecular Genetics, Immunology and BiotechnologyTunisTunisia
| | - Cécile Lecampion
- Aix-Marseille University, CEA, CNRS, BIAM, LGBP TeamMarseilleFrance
| | | | - Melanie Dussenne
- Aix-Marseille University, CEA, CNRS, BIAM, LGBP TeamMarseilleFrance
| | - Brigitte Ksas
- Aix-Marseille University, CEA, CNRS, BIAM, SAVE TeamSaint-Paul-lez-DuranceFrance
| | - Sylvie Citerne
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, INRAE Centre de Versailles-Grignon, Université Paris-SaclayVersaillesFrance
| | - Jose Caius
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2)OrsayFrance
- Université de Paris, CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2)OrsayFrance
| | | | - Hatem Fakhfakh
- University of Tunis El Manar, Faculty of Sciences of Tunis, Laboratory of Molecular Genetics, Immunology and BiotechnologyTunisTunisia
- University of Carthage, Faculty of Sciences of BizerteBizerteTunisia
| | - Stefano Caffarri
- Aix-Marseille University, CEA, CNRS, BIAM, LGBP TeamMarseilleFrance
| | - Michel Havaux
- Aix-Marseille University, CEA, CNRS, BIAM, SAVE TeamSaint-Paul-lez-DuranceFrance
| | - Ben Field
- Aix-Marseille University, CEA, CNRS, BIAM, LGBP TeamMarseilleFrance
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10
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Lan Y, Chen Q, Kong M, Liu Y, Lyu MJA, Perveen S, Mi H. PetM Is Essential for the Stabilization and Function of the Cytochrome b6f Complex in Arabidopsis. PLANT & CELL PHYSIOLOGY 2021; 62:1603-1614. [PMID: 34283246 DOI: 10.1093/pcp/pcab116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 07/16/2021] [Accepted: 07/20/2021] [Indexed: 06/13/2023]
Abstract
The cytochrome b6f (cyt b6f) acts as a common linker of electron transport between photosystems I and II in oxygenic photosynthesis. PetM, one of eight subunits of the cyt b6f complex, is a small hydrophobic subunit at the outside periphery, the functional mechanism of which remains to be elucidated in higher plants. In this work, we found that unlike the PetM mutant in Synechocystis sp. PCC 6803, the Arabidopsis thaliana PetM mutant showed a bleached phenotype with yellowish leaves, block of photosynthetic electron transport and loss of photo-autotrophy, similar to the Arabidopsis PetC mutant. Although PetM is relatively conserved between higher plants and cyanobacteria, Synechocystis PetM could not rescue the PetM-knockout phenotype in Arabidopsis. We provide evidence that the Synechocystis PetM did not stably bind to the Arabidopsis cyt b6f complex. Based on these results, we suggest that PetM is required by Arabidopsis to maintain the function of the cyt b6f complex, likely through its close link with core subunits to form a tight 'fence' that stabilizes the core of the complex.
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Affiliation(s)
- Yixin Lan
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qi Chen
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai 200032, China
| | - Mengmeng Kong
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai 200032, China
| | - Yanyun Liu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ming-Ju Amy Lyu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai 200032, China
| | - Shahnaz Perveen
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai 200032, China
| | - Hualing Mi
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai 200032, China
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11
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Krantz M, Legen J, Gao Y, Zoschke R, Schmitz-Linneweber C, Klipp E. Modeling indicates degradation of mRNA and protein as a potential regulation mechanisms during cold acclimation. JOURNAL OF PLANT RESEARCH 2021; 134:873-883. [PMID: 33891223 PMCID: PMC8245363 DOI: 10.1007/s10265-021-01294-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 03/31/2021] [Indexed: 05/21/2023]
Abstract
Plants are constantly exposed to temperature fluctuations, which have direct effects on all cellular reactions because temperature influences reaction likelihood and speed. Chloroplasts are crucial to temperature acclimation responses of plants, due to their photosynthetic reactions whose products play a central role in plant metabolism. Consequently, chloroplasts serve as sensors of temperature changes and are simultaneously major targets of temperature acclimation. The core subunits of the complexes involved in the light reactions of photosynthesis are encoded in the chloroplast. As a result, it is assumed that temperature acclimation in plants requires regulatory responses in chloroplast gene expression and protein turnover. We conducted western blot experiments to assess changes in the accumulation of two photosynthetic complexes (PSII, and Cytb6f complex) and the ATP synthase in tobacco plants over two days of acclimation to low temperature. Surprisingly, the concentration of proteins within the chloroplast varied negligibly compared to controls. To explain this observation, we used a simplified Ordinary Differential Equation (ODE) model of transcription, translation, mRNA degradation and protein degradation to explain how the protein concentration can be kept constant. This model takes into account temperature effects on these processes. Through simulations of the ODE model, we show that mRNA and protein degradation are possible targets for control during temperature acclimation. Our model provides a basis for future directions in research and the analysis of future results.
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Affiliation(s)
- Maria Krantz
- Theoretical Biophysics, Institute of Biology, Faculty of Life Sciences, Humboldt-Universität zu Berlin, 10099, Berlin, Germany
| | - Julia Legen
- Molecular Genetics, Institute of Biology, Faculty of Life Sciences, Humboldt-Universität zu Berlin, 10099, Berlin, Germany
| | - Yang Gao
- Translational Regulation in Plants, Max Planck Institute of Moleculare Plant Physiology, 14476, Potsdam, Germany
| | - Reimo Zoschke
- Translational Regulation in Plants, Max Planck Institute of Moleculare Plant Physiology, 14476, Potsdam, Germany
| | - Christian Schmitz-Linneweber
- Molecular Genetics, Institute of Biology, Faculty of Life Sciences, Humboldt-Universität zu Berlin, 10099, Berlin, Germany
| | - Edda Klipp
- Theoretical Biophysics, Institute of Biology, Faculty of Life Sciences, Humboldt-Universität zu Berlin, 10099, Berlin, Germany.
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12
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Satyanarayan MB, Zhao J, Zhang J, Yu F, Lu Y. Functional relationships of three NFU proteins in the biogenesis of chloroplastic iron-sulfur clusters. PLANT DIRECT 2021; 5:e00303. [PMID: 33553997 PMCID: PMC7851846 DOI: 10.1002/pld3.303] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 12/27/2020] [Accepted: 12/28/2020] [Indexed: 05/14/2023]
Abstract
Iron-sulfur clusters are required in a variety of biological processes. Biogenesis of iron-sulfur clusters includes assembly of iron-sulfur clusters on scaffold complexes and transfer of iron-sulfur clusters to recipient apoproteins by iron-sulfur carriers, such as nitrogen-fixation-subunit-U (NFU)-type proteins. Arabidopsis thaliana has three plastid-targeted NFUs: NFU1, NFU2, and NFU3. We previously discovered that nfu2 -/- nfu3 -/- mutants are embryo lethal. The lack of viable nfu2 -/- nfu3 -/- mutants posed a serious challenge. To overcome this problem, we characterized nfu2-1 -/- nfu3-2+/- and nfu2-1+/- nfu3-2 -/- sesquimutants. Simultaneous loss-of-function mutations in NFU2 and NFU3 have an additive effect on the declines of 4Fe-4S-containing PSI core subunits. Consequently, the sesquimutants had much lower PSI and PSII activities, much less chlorophyll, and much smaller plant sizes, than nfu2-1 and nfu3-2 single mutants. These observations are consistent with proposed roles of NFU3 and NFU2 in the biogenesis of chloroplastic 4Fe-4S. By performing spectroscopic and in vitro reconstitution experiments, we found that NFU1 may act as a carrier for chloroplastic 4Fe-4S and 3Fe-4S clusters. In line with this hypothesis, loss-of-function mutations in NFU1 resulted in significant declines in 4Fe-4S- and 3Fe-4S-containing chloroplastic proteins. The declines of PSI activity and 4Fe-4S-containing PSI core subunits in nfu1 mutants indicate that PSI is the main target of NFU1 action. The reductions in 4Fe-4S-containing PSI core proteins and PSI activity in nfu3-2, nfu2-1, and nfu1 single mutants suggest that all three plastid-targeted NFU proteins contribute to the biogenesis of chloroplastic 4Fe-4S clusters. Although different insertion sites of T-DNA lines may cause variations in phenotypic results, mutation severity could be an indicator of the relative importance of the gene product. Our results are consistent with the hypothesis that NFU3 contributes more than NFU2 and NFU2 contributes more than NFU1 to the production of 4Fe-4S-containing PSI core subunits.
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Affiliation(s)
- Manasa B. Satyanarayan
- Department of Biological SciencesWestern Michigan UniversityKalamazooMIUSA
- Present address:
Charles River LaboratoriesMattawanMIUSA
| | - Jun Zhao
- Department of Biological SciencesWestern Michigan UniversityKalamazooMIUSA
- Present address:
State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life SciencesNorthwest A&F UniversityYanglingChina
| | - Jessica Zhang
- Department of Biological SciencesWestern Michigan UniversityKalamazooMIUSA
| | - Fei Yu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life SciencesNorthwest A&F UniversityYanglingChina
| | - Yan Lu
- Department of Biological SciencesWestern Michigan UniversityKalamazooMIUSA
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13
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Moreno JC, Mi J, Agrawal S, Kössler S, Turečková V, Tarkowská D, Thiele W, Al-Babili S, Bock R, Schöttler MA. Expression of a carotenogenic gene allows faster biomass production by redesigning plant architecture and improving photosynthetic efficiency in tobacco. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:1967-1984. [PMID: 32623777 DOI: 10.1111/tpj.14909] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/23/2020] [Indexed: 05/11/2023]
Abstract
Because carotenoids act as accessory pigments in photosynthesis, play a key photoprotective role and are of major nutritional importance, carotenogenesis has been a target for crop improvement. Although carotenoids are important precursors of phytohormones, previous genetic manipulations reported little if any effects on biomass production and plant development, but resulted in specific modifications in carotenoid content. Unexpectedly, the expression of the carrot lycopene β-cyclase (DcLCYB1) in Nicotiana tabacum cv. Xanthi not only resulted in increased carotenoid accumulation, but also in altered plant architecture characterized by longer internodes, faster plant growth, early flowering and increased biomass. Here, we have challenged these transformants with a range of growth conditions to determine the robustness of their phenotype and analyze the underlying mechanisms. Transgenic DcLCYB1 lines showed increased transcript levels of key genes involved in carotenoid, chlorophyll, gibberellin (GA) and abscisic acid (ABA) biosynthesis, but also in photosynthesis-related genes. Accordingly, their carotenoid, chlorophyll, ABA and GA contents were increased. Hormone application and inhibitor experiments confirmed the key role of altered GA/ABA contents in the growth phenotype. Because the longer internodes reduce shading of mature leaves, induction of leaf senescence was delayed, and mature leaves maintained a high photosynthetic capacity. This increased total plant assimilation, as reflected in higher plant yields under both fully controlled constant and fluctuating light, and in non-controlled conditions. Furthermore, our data are a warning that engineering of isoprenoid metabolism can cause complex changes in phytohormone homeostasis and therefore plant development, which have not been sufficiently considered in previous studies.
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Affiliation(s)
- Juan C Moreno
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - Jianing Mi
- King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Shreya Agrawal
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - Stella Kössler
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - Veronika Turečková
- Laboratory of Growth Regulators, The Czech Academy of Sciences, Institute of Experimental Botany & Palacký University, Šlechtitelů 27, Olomouc, CZ-78371, Czech Republic
| | - Danuše Tarkowská
- Laboratory of Growth Regulators, The Czech Academy of Sciences, Institute of Experimental Botany & Palacký University, Šlechtitelů 27, Olomouc, CZ-78371, Czech Republic
| | - Wolfram Thiele
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - Salim Al-Babili
- King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Ralph Bock
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - Mark Aurel Schöttler
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
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14
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Agrawal S, Karcher D, Ruf S, Bock R. The Functions of Chloroplast Glutamyl-tRNA in Translation and Tetrapyrrole Biosynthesis. PLANT PHYSIOLOGY 2020; 183:263-276. [PMID: 32071153 PMCID: PMC7210637 DOI: 10.1104/pp.20.00009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 01/31/2020] [Indexed: 06/02/2023]
Abstract
The chloroplast glutamyl-tRNA (tRNAGlu) is unique in that it has two entirely different functions. In addition to acting in translation, it serves as the substrate of glutamyl-tRNA reductase (GluTR), the enzyme catalyzing the committed step in the tetrapyrrole biosynthetic pathway. How the tRNAGlu pool is distributed between the two pathways and whether tRNAGlu allocation limits tetrapyrrole biosynthesis and/or protein biosynthesis remains poorly understood. We generated a series of transplastomic tobacco (Nicotiana tabacum) plants to alter tRNAGlu expression levels and introduced a point mutation into the plastid trnE gene, which has been reported to uncouple protein biosynthesis from tetrapyrrole biosynthesis in chloroplasts of the protist Euglena gracilis We show that, rather than comparable uncoupling of the two pathways, the trnE mutation is lethal in tobacco because it inhibits tRNA processing, thus preventing translation of Glu codons. Ectopic expression of the mutated trnE gene uncovered an unexpected inhibition of glutamyl-tRNA reductase by immature tRNAGlu We further demonstrate that whereas overexpression of tRNAGlu does not affect tetrapyrrole biosynthesis, reduction of GluTR activity through inhibition by tRNAGlu precursors causes tetrapyrrole synthesis to become limiting in early plant development when active photosystem biogenesis provokes a high demand for de novo chlorophyll biosynthesis. Taken together, our findings provide insight into the roles of tRNAGlu at the intersection of protein biosynthesis and tetrapyrrole biosynthesis.
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Affiliation(s)
- Shreya Agrawal
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Daniel Karcher
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Stephanie Ruf
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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15
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Schuster M, Gao Y, Schöttler MA, Bock R, Zoschke R. Limited Responsiveness of Chloroplast Gene Expression during Acclimation to High Light in Tobacco. PLANT PHYSIOLOGY 2020; 182:424-435. [PMID: 31636102 PMCID: PMC6945831 DOI: 10.1104/pp.19.00953] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 10/08/2019] [Indexed: 05/21/2023]
Abstract
Acclimation to changing light intensities poses major challenges to plant metabolism and has been shown to involve regulatory adjustments in chloroplast gene expression. However, this regulation has not been examined at a plastid genome-wide level and for many genes, it is unknown whether their expression responds to altered light intensities. Here, we applied comparative ribosome profiling and transcriptomic experiments to analyze changes in chloroplast transcript accumulation and translation in leaves of tobacco (Nicotiana tabacum) seedlings after transfer from moderate light to physiological high light. Our time-course data revealed almost unaltered chloroplast transcript levels and only mild changes in ribosome occupancy during 2 d of high light exposure. Ribosome occupancy on the psbA mRNA (encoding the D1 reaction center protein of PSII) increased and that on the petG transcript decreased slightly after high light treatment. Transfer from moderate light to high light did not induce substantial alterations in ribosome pausing. Transfer experiments from low light to high light conditions resulted in strong PSII photoinhibition and revealed the distinct light-induced activation of psbA translation, which was further confirmed by reciprocal shift experiments. In low-light-to-high-light shift experiments, as well as reciprocal treatments, the expression of all other chloroplast genes remained virtually unaltered. Altogether, our data suggest that low light-acclimated plants upregulate the translation of a single chloroplast gene, psbA, during acclimation to high light. Our results indicate that psbA translation activation occurs already at moderate light intensities. Possible reasons for the otherwise mild effects of light intensity changes on gene expression in differentiated chloroplasts are discussed.
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Affiliation(s)
- Maja Schuster
- Department III, Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Yang Gao
- Department III, Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Mark Aurel Schöttler
- Department III, Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Department III, Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Reimo Zoschke
- Department III, Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
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16
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Loiacono FV, Thiele W, Schöttler MA, Tillich M, Bock R. Establishment of a Heterologous RNA Editing Event in Chloroplasts. PLANT PHYSIOLOGY 2019; 181:891-900. [PMID: 31519789 PMCID: PMC6836845 DOI: 10.1104/pp.19.00922] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 08/31/2019] [Indexed: 05/18/2023]
Abstract
In chloroplasts and plant mitochondria, specific cytidines in mRNAs are posttranscriptionally converted to uridines by RNA editing. Editing sites are recognized by nucleus-encoded RNA-binding proteins of the pentatricopeptide repeat (PPR) family, which bind upstream of the editing site in a sequence-specific manner and direct the editing activity to the target position. Editing sites have been lost many times during evolution by C-to-T mutations. Loss of an editing site is thought to be accompanied by loss or degeneration of its cognate PPR protein. Consequently, foreign editing sites are usually not recognized when introduced into species lacking the site. Previously, the spinach (Spinacia oleracea) psbF-26 editing site was introduced into the tobacco (Nicotiana tabacum) plastid genome. Tobacco lacks the psbF-26 site and cannot edit it. Expression of the "unedited" PsbF protein resulted in impaired PSII function. In Arabidopsis (Arabidopsis thaliana), the PPR protein LPA66 is required for editing at psbF-26. Here, we show that introduction of the Arabidopsis LPA66 reconstitutes editing of the spinach psbF-26 site in tobacco and restores a wild-type-like phenotype. Our findings define the minimum requirements for establishing new RNA editing sites and suggest that the evolutionary dynamics of editing patterns is largely explained by coevolution of editing sites and PPR proteins.
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Affiliation(s)
- Filomena Vanessa Loiacono
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Wolfram Thiele
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Mark Aurel Schöttler
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Michael Tillich
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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17
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Wang YY, Wang Y, Li GZ, Hao L. Salicylic acid-altering Arabidopsis plant response to cadmium exposure: Underlying mechanisms affecting antioxidation and photosynthesis-related processes. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 169:645-653. [PMID: 30496997 DOI: 10.1016/j.ecoenv.2018.11.062] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 11/09/2018] [Accepted: 11/15/2018] [Indexed: 06/09/2023]
Abstract
Previous studies have demonstrated that the genetic modification of basal salicylic acid (SA) level changed Arabidopsis plant response to cadmium (Cd) stress, but the mechanisms remain evaluated. In this study, Arabidopsis wild type (WT) and its SA-reducing transgenic line nahG (naphthalene hydroxylase G), SA-accumulating mutant snc1 (suppressor of nonexpressor of PR gene, constitutive 1) were exposed to 50 μM Cd2+ for 48 h or 7 d (just for assessing plant growth). The Cd treatment increased the expression levels of SA biosynthesis-related genes leading to enhanced SA accumulations in plant leaves, which was further confirmed by the expression patterns of SA marker genes. Cadmium accumulation was much higher in the Cd-exposed roots than in leaves, but was not affected by SA levels. Exposure to Cd inhibited plant growth of both aerial parts and roots, to a greater degree in snc1, and a lesser extent in nahG as compared with WT. Although Cd treatment increased plant antioxidative capacity, oxidative damage happened, especially to snc1 plants. Photoinhibition occurred in Cd-stressed plants leading to a decrease in photosynthetic activity, with a greater degree in snc1, while a lesser in nahG, as indicated by the changes of several key photosynthetic parameters. We comprehensively analyzed the expression profiles of photosynthesis-related genes, and observed a positive correlation between Cd tolerance and gene expression levels, wherein the transcription levels of two electron transport-related genes and two amylase-encoding genes were all up-regulated in nahG plants after Cd treatment, implying a significance of the related processes in this genotype against Cd stress.
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Affiliation(s)
- Yuan-Yuan Wang
- College of Life Science, Shenyang Normal University, Shenyang 110034, China
| | - Yu Wang
- College of Life Science, Shenyang Normal University, Shenyang 110034, China
| | - Guang-Zhe Li
- College of Life Science, Shenyang Normal University, Shenyang 110034, China.
| | - Lin Hao
- College of Life Science, Shenyang Normal University, Shenyang 110034, China.
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18
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Simkin AJ, López-Calcagno PE, Raines CA. Feeding the world: improving photosynthetic efficiency for sustainable crop production. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:1119-1140. [PMID: 30772919 PMCID: PMC6395887 DOI: 10.1093/jxb/ery445] [Citation(s) in RCA: 224] [Impact Index Per Article: 44.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/27/2018] [Indexed: 05/18/2023]
Abstract
A number of recent studies have provided strong support demonstrating that improving the photosynthetic processes through genetic engineering can provide an avenue to improve yield potential. The major focus of this review is on improvement of the Calvin-Benson cycle and electron transport. Consideration is also given to how altering regulatory process may provide an additional route to increase photosynthetic efficiency. Here we summarize some of the recent successes that have been observed through genetic manipulation of photosynthesis, showing that, in both the glasshouse and the field, yield can be increased by >40%. These results provide a clear demonstration of the potential for increasing yield through improvements in photosynthesis. In the final section, we consider the need to stack improvement in photosynthetic traits with traits that target the yield gap in order to provide robust germplasm for different crops across the globe.
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Affiliation(s)
- Andrew J Simkin
- NIAB EMR, New Road, East Malling, Kent, UK
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester, UK
| | | | - Christine A Raines
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester, UK
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19
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Naumann M, Hubberten HM, Watanabe M, Hänsch R, Schöttler MA, Hoefgen R. Sulfite Reductase Co-suppression in Tobacco Reveals Detoxification Mechanisms and Downstream Responses Comparable to Sulfate Starvation. FRONTIERS IN PLANT SCIENCE 2018; 9:1423. [PMID: 30374361 PMCID: PMC6196246 DOI: 10.3389/fpls.2018.01423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 09/07/2018] [Indexed: 05/30/2023]
Abstract
Sulfite reductase (SIR) is a key enzyme in higher plants in the assimilatory sulfate reduction pathway. SIR, being exclusively localized in plastids, catalyzes the reduction of sulfite (SO3 2-) to sulfide (S2-) and is essential for plant life. We characterized transgenic plants leading to co-suppression of the SIR gene in tobacco (Nicotiana tabacum cv. Samsun NN). Co-suppression resulted in reduced but not completely extinguished expression of SIR and in a reduction of SIR activity to about 20-50% of the activity in control plants. The reduction of SIR activity caused chlorotic and necrotic phenotypes in tobacco leaves, but with varying phenotype strength even among clones and increasing from young to old leaves. In transgenic plants compared to control plants, metabolite levels upstream of SIR accumulated, such as sulfite, sulfate and thiosulfate. The levels of downstream metabolites were reduced, such as cysteine, glutathione (GSH) and methionine. This metabolic signature resembles a sulfate deprivation phenotype as corroborated by the fact that O-acetylserine (OAS) accumulated. Further, chlorophyll contents, photosynthetic electron transport, and the contents of carbohydrates such as starch, sucrose, fructose, and glucose were reduced. Amino acid compositions were altered in a complex manner due to the reduction of contents of cysteine, and to some extent methionine. Interestingly, sulfide levels remained constant indicating that sulfide homeostasis is crucial for plant performance and survival. Additionally, this allows concluding that sulfide does not act as a signal in this context to control sulfate uptake and assimilation. The accumulation of upstream compounds hints at detoxification mechanisms and, additionally, a control exerted by the downstream metabolites on the sulfate uptake and assimilation system. Co-suppression lines showed increased sensitivity to additionally imposed stresses probably due to the accumulation of reactive compounds because of insufficient detoxification in combination with reduced GSH levels.
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Affiliation(s)
- Marcel Naumann
- Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
- Division of Quality of Plant Products, Department of Crop Sciences, University of Göttingen, Göttingen, Germany
| | | | - Mutsumi Watanabe
- Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
- Nara Institute of Science and Technology, Ikoma, Japan
| | - Robert Hänsch
- Department of Plant Biology, Technische Universität Braunschweig, Braunschweig, Germany
| | | | - Rainer Hoefgen
- Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
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20
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Patil M, Seifert S, Seiler F, Soll J, Schwenkert S. FZL is primarily localized to the inner chloroplast membrane however influences thylakoid maintenance. PLANT MOLECULAR BIOLOGY 2018; 97:421-433. [PMID: 29951988 DOI: 10.1007/s11103-018-0748-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 06/05/2018] [Indexed: 06/08/2023]
Abstract
FZL is primarily localized to the chloroplast inner envelope and not to the thylakoids, but nevertheless affects the maintenance of thylakoid membranes and photosynthetic protein complexes. The fuzzy-onion-like protein (FZL) is a membrane-bound dynamin-like GTPase located in the chloroplast. We have investigated the chloroplast sub-localization of the endogenous FZL protein and found it to be primarily localized to the inner envelope. Moreover, we observed that mature leaves of fzl mutants start to turn pale, especially in the midvein area of the leaves, 11 days after germination. We therefore assessed their photosynthetic performance as well as the accumulation of thylakoid membrane proteins and complexes after the initial appearance of the phenotype. Interestingly, we could observe a significant decrease in amounts of the cytochrome b6f complex in 20-day-old mutants, which was also reflected in an impaired electron transport rate as well as a more oxidized P700 redox state. Analysis of differences in transcriptome datasets obtained before and after onset of the phenotype, revealed large-scale changes in gene expression after the phenotype became visible. In summary, we propose that FZL, despite its localization in the inner chloroplast envelope has an important role in thylakoid maintenance in mature and aging leaves.
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Affiliation(s)
- Manali Patil
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse. 2-4, 82152, Planegg-Martinsried, Germany
- Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377, Munich, Germany
| | - Stephanie Seifert
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse. 2-4, 82152, Planegg-Martinsried, Germany
| | - Franka Seiler
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse. 2-4, 82152, Planegg-Martinsried, Germany
| | - Jürgen Soll
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse. 2-4, 82152, Planegg-Martinsried, Germany
- Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377, Munich, Germany
| | - Serena Schwenkert
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse. 2-4, 82152, Planegg-Martinsried, Germany.
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21
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Extensive gain and loss of photosystem I subunits in chromerid algae, photosynthetic relatives of apicomplexans. Sci Rep 2017; 7:13214. [PMID: 29038514 PMCID: PMC5643376 DOI: 10.1038/s41598-017-13575-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 09/26/2017] [Indexed: 12/16/2022] Open
Abstract
In oxygenic photosynthesis the initial photochemical processes are carried out by photosystem I (PSI) and II (PSII). Although subunit composition varies between cyanobacterial and plastid photosystems, the core structures of PSI and PSII are conserved throughout photosynthetic eukaryotes. So far, the photosynthetic complexes have been characterised in only a small number of organisms. We performed in silico and biochemical studies to explore the organization and evolution of the photosynthetic apparatus in the chromerids Chromera velia and Vitrella brassicaformis, autotrophic relatives of apicomplexans. We catalogued the presence and location of genes coding for conserved subunits of the photosystems as well as cytochrome b6f and ATP synthase in chromerids and other phototrophs and performed a phylogenetic analysis. We then characterised the photosynthetic complexes of Chromera and Vitrella using 2D gels combined with mass-spectrometry and further analysed the purified Chromera PSI. Our data suggest that the photosynthetic apparatus of chromerids underwent unique structural changes. Both photosystems (as well as cytochrome b6f and ATP synthase) lost several canonical subunits, while PSI gained one superoxide dismutase (Vitrella) or two superoxide dismutases and several unknown proteins (Chromera) as new regular subunits. We discuss these results in light of the extraordinarily efficient photosynthetic processes described in Chromera.
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Simkin AJ, McAusland L, Lawson T, Raines CA. Overexpression of the RieskeFeS Protein Increases Electron Transport Rates and Biomass Yield. PLANT PHYSIOLOGY 2017; 175:134-145. [PMID: 28754840 DOI: 10.1101/133702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/27/2017] [Indexed: 05/22/2023]
Abstract
In this study, we generated transgenic Arabidopsis (Arabidopsis thaliana) plants overexpressing the Rieske FeS protein (PetC), a component of the cytochrome b6f (cyt b6f) complex. Increasing the levels of this protein resulted in concomitant increases in the levels of cyt f (PetA) and cyt b6 (PetB), core proteins of the cyt b6f complex. Interestingly, an increase in the levels of proteins in both the photosystem I (PSI) and PSII complexes also was seen in the Rieske FeS overexpression plants. Although the mechanisms leading to these changes remain to be identified, the transgenic plants presented here provide novel tools to explore this. Importantly, overexpression of the Rieske FeS protein resulted in substantial and significant impacts on the quantum efficiency of PSI and PSII, electron transport, biomass, and seed yield in Arabidopsis plants. These results demonstrate the potential for manipulating electron transport processes to increase crop productivity.
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Affiliation(s)
- Andrew J Simkin
- School of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Lorna McAusland
- School of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Tracy Lawson
- School of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Christine A Raines
- School of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
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23
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Simkin AJ, McAusland L, Lawson T, Raines CA. Overexpression of the RieskeFeS Protein Increases Electron Transport Rates and Biomass Yield. PLANT PHYSIOLOGY 2017; 175:134-145. [PMID: 28754840 PMCID: PMC5580758 DOI: 10.1104/pp.17.00622] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/27/2017] [Indexed: 05/18/2023]
Abstract
In this study, we generated transgenic Arabidopsis (Arabidopsis thaliana) plants overexpressing the Rieske FeS protein (PetC), a component of the cytochrome b6f (cyt b6f) complex. Increasing the levels of this protein resulted in concomitant increases in the levels of cyt f (PetA) and cyt b6 (PetB), core proteins of the cyt b6f complex. Interestingly, an increase in the levels of proteins in both the photosystem I (PSI) and PSII complexes also was seen in the Rieske FeS overexpression plants. Although the mechanisms leading to these changes remain to be identified, the transgenic plants presented here provide novel tools to explore this. Importantly, overexpression of the Rieske FeS protein resulted in substantial and significant impacts on the quantum efficiency of PSI and PSII, electron transport, biomass, and seed yield in Arabidopsis plants. These results demonstrate the potential for manipulating electron transport processes to increase crop productivity.
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Affiliation(s)
- Andrew J Simkin
- School of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Lorna McAusland
- School of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Tracy Lawson
- School of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Christine A Raines
- School of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
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24
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Wittenberg G, Järvi S, Hojka M, Tóth SZ, Meyer EH, Aro EM, Schöttler MA, Bock R. Identification and characterization of a stable intermediate in photosystem I assembly in tobacco. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 90:478-490. [PMID: 28161893 DOI: 10.1111/tpj.13505] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 01/29/2017] [Accepted: 01/31/2017] [Indexed: 05/06/2023]
Abstract
Photosystem I (PSI) is the most efficient bioenergetic nanomachine in nature and one of the largest membrane protein complexes known. It is composed of 18 protein subunits that bind more than 200 co-factors and prosthetic groups. While the structure and function of PSI have been studied in great detail, very little is known about the PSI assembly process. In this work, we have characterized a PSI assembly intermediate in tobacco plants, which we named PSI*. We found PSI* to contain only a specific subset of the core subunits of PSI. PSI* is particularly abundant in young leaves where active thylakoid biogenesis takes place. Moreover, PSI* was found to overaccumulate in PsaF-deficient mutant plants, and we show that re-initiation of PsaF synthesis promotes the maturation of PSI* into PSI. The attachment of antenna proteins to PSI also requires the transition from PSI* to mature PSI. Our data could provide a biochemical entry point into the challenging investigation of PSI biogenesis and allow us to improve the model for the assembly pathway of PSI in thylakoid membranes of vascular plants.
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Affiliation(s)
- Gal Wittenberg
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476, Potsdam-Golm, Germany
| | - Sari Järvi
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Marta Hojka
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476, Potsdam-Golm, Germany
| | - Szilvia Z Tóth
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476, Potsdam-Golm, Germany
| | - Etienne H Meyer
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476, Potsdam-Golm, Germany
| | - Eva-Mari Aro
- Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014, Turku, Finland
| | - Mark A Schöttler
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476, Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476, Potsdam-Golm, Germany
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25
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Zhu H, Zeng LD, Yi XP, Peng CL, Zhang WF, Chow WS. The half-life of the cytochrome bf complex in leaves of pea plants after transfer from moderately-high growth light to low light. FUNCTIONAL PLANT BIOLOGY : FPB 2017; 44:351-357. [PMID: 32480569 DOI: 10.1071/fp16222] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/24/2016] [Indexed: 05/14/2023]
Abstract
The content of cytochrome (cyt) bf complex is the main rate-limiting factor that determines light- and CO2-saturated photosynthetic capacity. A study of the half-life of the cyt f content in leaves was conducted whereby Pisum sativum L. plants, grown in moderately high light (HL), were transferred to low light (LL). The cyt f content in fully-expanded leaves decreased steadily over the 2 weeks after the HL-to-LL transfer, whereas control leaves in HL retained their high contents. The difference between the time courses of HL-to-LL plants and control HL plants represents the time course of loss of cyt f content, with a half-life of 1.7 days, which is >3-fold shorter than that reported for tobacco leaves at constant growth irradiance using an RNA interference approach (Hojka et al. 2014). After transfer to LL (16h photoperiod), pea plants were re-exposed to HL for 0, 1.5h or 5h during the otherwise LL photoperiod, but the cyt f content of fully-expanded leaves declined practically at the same rate regardless of whether HL was re-introduced for 0, 1.5h or 5h during each 16h LL photoperiod. It appears that fully-expanded leaves, having matured under HL, were unable to increase their cyt f content when re-introduced to HL. These findings are relevant to any attempts to maintain a high photosynthetic capacity when the growth irradiance is temporarily decreased by shading or overcast weather.
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Affiliation(s)
- Hui Zhu
- School of Life Science and Food Technology, Hanshan Normal University, Chaozhou City 521041, Guangdong Province, PR China
| | - Ling-Da Zeng
- Department of Life Sciences, Huizhou University, Huizhou City 516007, Guangdong Province, PR China
| | - Xiao-Ping Yi
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China
| | - Chang-Lian Peng
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, College of Life Sciences, South China Normal University, Guangzhou 510631, PR China
| | - Wang-Feng Zhang
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China
| | - Wah Soon Chow
- Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
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26
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Schöttler MA, Thiele W, Belkius K, Bergner SV, Flügel C, Wittenberg G, Agrawal S, Stegemann S, Ruf S, Bock R. The plastid-encoded PsaI subunit stabilizes photosystem I during leaf senescence in tobacco. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:1137-1155. [PMID: 28180288 PMCID: PMC5429015 DOI: 10.1093/jxb/erx009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
PsaI is the only subunit of PSI whose precise physiological function has not yet been elucidated in higher plants. While PsaI is involved in PSI trimerization in cyanobacteria, trimerization was lost during the evolution of the eukaryotic PSI, and the entire PsaI side of PSI underwent major structural remodelling to allow for binding of light harvesting complex II antenna proteins during state transitions. Here, we have generated a tobacco (Nicotiana tabacum) knockout mutant of the plastid-encoded psaI gene. We show that PsaI is not required for the redox reactions of PSI. Neither plastocyanin oxidation nor the processes at the PSI acceptor side are impaired in the mutant, and both linear and cyclic electron flux rates are unaltered. The PSI antenna cross section is unaffected, state transitions function normally, and binding of other PSI subunits to the reaction centre is not compromised. Under a wide range of growth conditions, the mutants are phenotypically and physiologically indistinguishable from wild-type tobacco. However, in response to high-light and chilling stress, and especially during leaf senescence, PSI content is reduced in the mutants, indicating that the I-subunit plays a role in stabilizing PSI complexes.
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Affiliation(s)
- Mark Aurel Schöttler
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Wolfram Thiele
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Karolina Belkius
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Sonja Verena Bergner
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Claudia Flügel
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Gal Wittenberg
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Shreya Agrawal
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Sandra Stegemann
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Stephanie Ruf
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
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27
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Nath K, Wessendorf RL, Lu Y. A Nitrogen-Fixing Subunit Essential for Accumulating 4Fe-4S-Containing Photosystem I Core Proteins. PLANT PHYSIOLOGY 2016; 172:2459-2470. [PMID: 27784767 PMCID: PMC5129733 DOI: 10.1104/pp.16.01564] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 10/25/2016] [Indexed: 05/07/2023]
Abstract
Nitrogen-fixation-subunit-U (NFU)-type proteins have been shown to be involved in the biogenesis of iron-sulfur clusters. We investigated the molecular function of a chloroplastic NFU-type iron-sulfur scaffold protein, NFU3, in Arabidopsis (Arabidopsis thaliana) using genetics approaches. Loss-of-function mutations in the NFU3 gene caused yellow pigmentation in leaves, reductions in plant size, leaf size, and growth rate, delay in flowering and seeding, and decreases in seed production. Biochemical and physiological analyses indicated that these defects are due to the substantial reductions in the abundances of 4Fe-4S-containing photosystem I (PSI) core subunits PsaA (where Psa stands for PSI), PsaB, and PsaC and a nearly complete loss of PSI activity. In addition to the substantial decreases in the amounts of PSI core proteins, the content of 3Fe-4S-containing ferredoxin-dependent glutamine oxoglutarate aminotransferases declined significantly in the nfu3 mutants. Furthermore, the absorption spectrum of the recombinant NFU3 protein showed features characteristic of 4Fe-4S and 3Fe-4S clusters, and the in vitro reconstitution experiment indicated an iron-sulfur scaffold function of NFU3. These data demonstrate that NFU3 is involved in the assembly and transfer of 4Fe-4S and 3Fe-4S clusters and that NFU3 is required for the accumulation of 4Fe-4S- and 3Fe-4S-containing proteins, especially 4Fe-4S-containing PSI core subunits, in the Arabidopsis chloroplast.
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Affiliation(s)
- Krishna Nath
- Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008-5410
| | - Ryan L Wessendorf
- Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008-5410
| | - Yan Lu
- Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan 49008-5410
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28
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Vanlerberghe GC, Martyn GD, Dahal K. Alternative oxidase: a respiratory electron transport chain pathway essential for maintaining photosynthetic performance during drought stress. PHYSIOLOGIA PLANTARUM 2016; 157:322-37. [PMID: 27080742 DOI: 10.1111/ppl.12451] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 03/11/2016] [Indexed: 05/19/2023]
Abstract
Photosynthesis and respiration are the hubs of energy metabolism in plants. Drought strongly perturbs photosynthesis as a result of both diffusive limitations resulting from stomatal closure, and in some cases biochemical limitations that are associated with a reduced abundance of key photosynthetic components. The effects of drought on respiration, particularly respiration in the light (RL ), are less understood. The plant mitochondrial electron transport chain includes a non-energy conserving terminal oxidase called alternative oxidase (AOX). Several studies have shown that drought increases AOX transcript, protein and maximum capacity. Here we review recent studies comparing wild-type (WT) tobacco to transgenic lines with altered AOX protein amount. Specifically during drought, RL was compromised in AOX knockdown plants and enhanced in AOX overexpression plants, compared with WT. Significantly, these differences in RL were accompanied by dramatic differences in photosynthetic performance. Knockdown of AOX increased the susceptibility of photosynthesis to drought-induced biochemical limitations, while overexpression of AOX delayed the development of such biochemical limitations, compared with WT. Overall, the results indicate that AOX is essential to maintaining RL during drought, and that this non-energy conserving respiration maintains photosynthesis during drought by promoting energy balance in the chloroplast. This review also outlines several areas for future research, including the possibility that enhancement of non-energy conserving respiratory electron sinks may be a useful biotechnological approach to increase plant performance during stress.
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Affiliation(s)
- Greg C Vanlerberghe
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, M1C1A4, Canada
- Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, ON, M1C1A4, Canada
| | - Greg D Martyn
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, M1C1A4, Canada
- Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, ON, M1C1A4, Canada
| | - Keshav Dahal
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, M1C1A4, Canada
- Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, ON, M1C1A4, Canada
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29
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Raven JA. Implications of mutation of organelle genomes for organelle function and evolution. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:5639-50. [PMID: 26077836 DOI: 10.1093/jxb/erv298] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Organelle genomes undergo more variation, including that resulting from damage, than eukaryotic nuclear genomes, or bacterial genomes, under the same conditions. Recent advances in characterizing the changes to genomes of chloroplasts and mitochondria of Zea mays should, when applied more widely, help our understanding of how damage to organelle genomes relates to how organelle function is maintained through the life of individuals and in succeeding generations. Understanding of the degree of variation in the changes to organelle DNA and its repair among photosynthetic organisms might help to explain the variations in the rate of nucleotide substitution among organelle genomes. Further studies of organelle DNA variation, including that due to damage and its repair might also help us to understand why the extent of DNA turnover in the organelles is so much greater than that in their bacterial (cyanobacteria for chloroplasts, proteobacteria for mitochondria) relatives with similar rates of production of DNA-damaging reactive oxygen species. Finally, from the available data, even the longest-lived organelle-encoded proteins, and the RNAs needed for their synthesis, are unlikely to maintain organelle function for much more than a week after the complete loss of organelle DNA.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK †School of Plant Biology, University of Western Australia, M048, 35 Stirling Highway, Crawley, WA 6009, Australia
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30
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Schöttler MA, Tóth SZ, Boulouis A, Kahlau S. Photosynthetic complex stoichiometry dynamics in higher plants: biogenesis, function, and turnover of ATP synthase and the cytochrome b6f complex. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:2373-400. [PMID: 25540437 DOI: 10.1093/jxb/eru495] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
During plant development and in response to fluctuating environmental conditions, large changes in leaf assimilation capacity and in the metabolic consumption of ATP and NADPH produced by the photosynthetic apparatus can occur. To minimize cytotoxic side reactions, such as the production of reactive oxygen species, photosynthetic electron transport needs to be adjusted to the metabolic demand. The cytochrome b6f complex and chloroplast ATP synthase form the predominant sites of photosynthetic flux control. Accordingly, both respond strongly to changing environmental conditions and metabolic states. Usually, their contents are strictly co-regulated. Thereby, the capacity for proton influx into the lumen, which is controlled by electron flux through the cytochrome b6f complex, is balanced with proton efflux through ATP synthase, which drives ATP synthesis. We discuss the environmental, systemic, and metabolic signals triggering the stoichiometry adjustments of ATP synthase and the cytochrome b6f complex. The contribution of transcriptional and post-transcriptional regulation of subunit synthesis, and the importance of auxiliary proteins required for complex assembly in achieving the stoichiometry adjustments is described. Finally, current knowledge on the stability and turnover of both complexes is summarized.
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Affiliation(s)
- Mark Aurel Schöttler
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Szilvia Z Tóth
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Alix Boulouis
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Sabine Kahlau
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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31
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Charuvi D, Nevo R, Shimoni E, Naveh L, Zia A, Adam Z, Farrant JM, Kirchhoff H, Reich Z. Photoprotection conferred by changes in photosynthetic protein levels and organization during dehydration of a homoiochlorophyllous resurrection plant. PLANT PHYSIOLOGY 2015; 167:1554-65. [PMID: 25713340 PMCID: PMC4378169 DOI: 10.1104/pp.114.255794] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 02/20/2015] [Indexed: 05/18/2023]
Abstract
During desiccation, homoiochlorophyllous resurrection plants retain most of their photosynthetic apparatus, allowing them to resume photosynthetic activity quickly upon water availability. These plants rely on various mechanisms to prevent the formation of reactive oxygen species and/or protect their tissues from the damage they inflict. In this work, we addressed the issue of how homoiochlorophyllous resurrection plants deal with the problem of excessive excitation/electron pressures during dehydration using Craterostigma pumilum as a model plant. To investigate the alterations in the supramolecular organization of photosynthetic protein complexes, we examined cryoimmobilized, freeze-fractured leaf tissues using (cryo)scanning electron microscopy. These examinations revealed rearrangements of photosystem II (PSII) complexes, including a lowered density during moderate dehydration, consistent with a lower level of PSII proteins, as shown by biochemical analyses. The latter also showed a considerable decrease in the level of cytochrome f early during dehydration, suggesting that initial regulation of the inhibition of electron transport is achieved via the cytochrome b6f complex. Upon further dehydration, PSII complexes are observed to arrange into rows and semicrystalline arrays, which correlates with the significant accumulation of sucrose and the appearance of inverted hexagonal lipid phases within the membranes. As opposed to PSII and cytochrome f, the light-harvesting antenna complexes of PSII remain stable throughout the course of dehydration. Altogether, these results, along with photosynthetic activity measurements, suggest that the protection of retained photosynthetic components is achieved, at least in part, via the structural rearrangements of PSII and (likely) light-harvesting antenna complexes into a photochemically quenched state.
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Affiliation(s)
- Dana Charuvi
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Reinat Nevo
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Eyal Shimoni
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Leah Naveh
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Ahmad Zia
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Zach Adam
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Jill M Farrant
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Helmut Kirchhoff
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
| | - Ziv Reich
- Department of Biological Chemistry (D.C., R.N., Z.R.) and Electron Microscopy Unit (E.S.), Weizmann Institute of Science, Rehovot 76100, Israel;Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (L.N., Z.A.);Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (A.Z., H.K.); andDepartment of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa (J.M.F.)
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