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Goggin FL, Fischer HD. Singlet oxygen signalling and its potential roles in plant biotic interactions. PLANT, CELL & ENVIRONMENT 2024; 47:1957-1970. [PMID: 38372069 DOI: 10.1111/pce.14851] [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: 11/13/2023] [Revised: 01/25/2024] [Accepted: 01/27/2024] [Indexed: 02/20/2024]
Abstract
Singlet oxygen (SO) is among the most potent reactive oxygen species, and readily oxidizes proteins, lipids and DNA. It can be generated at the plant surface by phototoxins in the epidermis, acting as a direct defense against pathogens and herbivores (including humans). SO can also accumulate within mitochondria, peroxisomes, cytosol and the nucleus through multiple enzymatic and nonenzymatic processes. However, the majority of research on intracellular SO generation in plants has focused on transfer of light energy to triplet oxygen by photopigments from the chloroplast. SO accumulates in response to diverse stresses that perturb chloroplast metabolism, and while its high reactivity limits diffusion distances, it participates in retrograde signalling through the EXECUTER1 sensor, generation of carotenoid metabolites and possibly other unknown pathways. SO thereby reprogrammes nuclear gene expression and modulates hormone signalling and programmed cell death. While SO signalling has long been known to regulate plant responses to high-light stress, recent literature also suggests a role in plant interactions with insects, bacteria and fungi. The goals of this review are to provide a brief overview of SO, summarize evidence for its involvement in biotic stress responses and discuss future directions for the study of SO in defense signalling.
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Affiliation(s)
- Fiona L Goggin
- Department of Entomology and Plant Pathology, University of Arkansas System Division of Agriculture, Fayetteville, Arkansas, USA
| | - Hillary D Fischer
- Department of Entomology and Plant Pathology, University of Arkansas System Division of Agriculture, Fayetteville, Arkansas, USA
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2
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Tikhonov AN. The cytochrome b 6f complex: plastoquinol oxidation and regulation of electron transport in chloroplasts. PHOTOSYNTHESIS RESEARCH 2024; 159:203-227. [PMID: 37369875 DOI: 10.1007/s11120-023-01034-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023]
Abstract
In oxygenic photosynthetic systems, the cytochrome b6f (Cytb6f) complex (plastoquinol:plastocyanin oxidoreductase) is a heart of the hub that provides connectivity between photosystems (PS) II and I. In this review, the structure and function of the Cytb6f complex are briefly outlined, being focused on the mechanisms of a bifurcated (two-electron) oxidation of plastoquinol (PQH2). In plant chloroplasts, under a wide range of experimental conditions (pH and temperature), a diffusion of PQH2 from PSII to the Cytb6f does not limit the intersystem electron transport. The overall rate of PQH2 turnover is determined mainly by the first step of the bifurcated oxidation of PQH2 at the catalytic site Qo, i.e., the reaction of electron transfer from PQH2 to the Fe2S2 cluster of the high-potential Rieske iron-sulfur protein (ISP). This point has been supported by the quantum chemical analysis of PQH2 oxidation within the framework of a model system including the Fe2S2 cluster of the ISP and surrounding amino acids, the low-potential heme b6L, Glu78 and 2,3,5-trimethylbenzoquinol (the tail-less analog of PQH2). Other structure-function relationships and mechanisms of electron transport regulation of oxygenic photosynthesis associated with the Cytb6f complex are briefly outlined: pH-dependent control of the intersystem electron transport and the regulatory balance between the operation of linear and cyclic electron transfer chains.
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Affiliation(s)
- Alexander N Tikhonov
- Department of Biophysics, Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russian Federation, 119991.
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3
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Tikhonov AN. Electron Transport in Chloroplasts: Regulation and Alternative Pathways of Electron Transfer. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1438-1454. [PMID: 38105016 DOI: 10.1134/s0006297923100036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/09/2023] [Accepted: 07/09/2023] [Indexed: 12/19/2023]
Abstract
This work represents an overview of electron transport regulation in chloroplasts as considered in the context of structure-function organization of photosynthetic apparatus in plants. Main focus of the article is on bifurcated oxidation of plastoquinol by the cytochrome b6f complex, which represents the rate-limiting step of electron transfer between photosystems II and I. Electron transport along the chains of non-cyclic, cyclic, and pseudocyclic electron flow, their relationships to generation of the trans-thylakoid difference in electrochemical potentials of protons in chloroplasts, and pH-dependent mechanisms of regulation of the cytochrome b6f complex are considered. Redox reactions with participation of molecular oxygen and ascorbate, alternative mediators of electron transport in chloroplasts, have also been discussed.
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Law SSY, Miyamoto T, Numata K. Organelle-targeted gene delivery in plants by nanomaterials. Chem Commun (Camb) 2023. [PMID: 37183975 DOI: 10.1039/d3cc00962a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Genetic engineering of plants has revolutionized agriculture and has had a significant impact on our everyday life. It has allowed for the production of crops with longer shelf lives, enhanced yields and resistance to pests and disease. The application of nanomaterials in plant genetic engineering has further augmented these programs with higher delivery efficiencies, biocompatibility and the potential for plant regeneration. In particular, subcellular targeting using nanomaterials has recently become possible with the cutting-edge developments within nanomaterials, but remains challenging despite the promise in organellar engineering for the introduction of useful traits and the elucidation of subcellular interactions. This feature article provides an overview of nanomaterial delivery within plants and highlights the application of recent progress in nanomaterials for subcellular organelle-targeted delivery.
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Affiliation(s)
- Simon Sau Yin Law
- Biomacromolecules Research Team, RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan.
| | - Takaaki Miyamoto
- Biomacromolecules Research Team, RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan.
| | - Keiji Numata
- Biomacromolecules Research Team, RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan.
- Department of Material Chemistry, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
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Ichikawa S, Ishikawa K, Miyakawa H, Kodama Y. Live-cell imaging of the chloroplast outer envelope membrane using fluorescent dyes. PLANT DIRECT 2022; 6:e462. [PMID: 36398034 PMCID: PMC9666008 DOI: 10.1002/pld3.462] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 10/15/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
UNLABELLED Chloroplasts are organelles composed of sub-organellar compartments-stroma, thylakoids, and starch granules-and are surrounded by outer and inner envelope membranes (OEM and IEM, respectively). The chloroplast OEM and IEM play key roles not only as a barrier separating the chloroplast components from the cytosol but also in the interchange of numerous metabolites and proteins between the chloroplast interior and the cytosol. Fluorescent protein markers for the chloroplast OEM have been widely used to visualize the outermost border of chloroplasts. However, the use of marker proteins requires an established cellular genetic transformation method, which limits the plant species in which marker proteins can be used. Moreover, the high accumulation of OEM marker proteins often elicits abnormal morphological phenotypes of the OEM. Because the OEM can currently only be visualized using exogenous marker proteins, the behaviors of the chloroplast and/or its OEM remain unknown in wild-type cells of various plant species. Here, we visualized the OEM using live-cell staining with the fluorescent dyes rhodamine B and Nile red in several plant species, including crops. We propose rhodamine B and Nile red as new tools for visualizing the chloroplast OEM in living plant cells that do not require genetic transformation. SIGNIFICANCE STATEMENT We established a live-cell imaging method to visualize the chloroplast outer envelope membrane by staining living cells with fluorescent dyes. This method does not require genetic transformation and allows the observation of the chloroplast outer envelope membrane in various plant species.
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Affiliation(s)
- Shintaro Ichikawa
- Center for Bioscience Research and EducationUtsunomiya UniversityTochigiJapan
- Graduate School of Regional Development and CreativityUtsunomiya UniversityTochigiJapan
| | - Kazuya Ishikawa
- Center for Bioscience Research and EducationUtsunomiya UniversityTochigiJapan
| | - Hitoshi Miyakawa
- Center for Bioscience Research and EducationUtsunomiya UniversityTochigiJapan
- Graduate School of Regional Development and CreativityUtsunomiya UniversityTochigiJapan
| | - Yutaka Kodama
- Center for Bioscience Research and EducationUtsunomiya UniversityTochigiJapan
- Graduate School of Regional Development and CreativityUtsunomiya UniversityTochigiJapan
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6
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Sun Y, Zang Y, Chen J, Shang S, Wang J, Liu Q, Tang X. The differing responses of central carbon cycle metabolism in male and female Sargassum thunbergii to ultraviolet-B radiation. FRONTIERS IN PLANT SCIENCE 2022; 13:904943. [PMID: 36262652 PMCID: PMC9574197 DOI: 10.3389/fpls.2022.904943] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 09/08/2022] [Indexed: 06/16/2023]
Abstract
The enhancement of ultraviolet-B radiation (UV-B) radiation reaching the Earth's surface due to ozone layer depletion is an important topic. Macroalgal species growing in the intertidal zone are often directly exposed to UV-B radiation periodically as the tide changes. In order to better understand the response of macroalgae to UV-B stressed condition, we studied the dominant dioecious intertidal macroalgae Sargassum thunbergii. After consecutive UV-B radiation treatments, we used metabonomics models to analyze and compare the maximum photosynthetic electron transport rate (ETRmax), central carbon cycle metabolism (CCCM) gene expression level, CCCM enzymic activities [pyruvate dehydrogenase and citrate synthase (PDH and CS)], and carbon-based metabolite (including pyruvate, soluble sugar, total amino acid, and lipids) content in male and female S. thunbergii. The results showed that under low and high UV-B radiation, the ETRmax values and six targeted CCCM gene expression levels were significantly higher in males than in females. Under high UV-B radiation, only the CS activity was significantly higher in males than in females. There was no significant difference in PDH activity between males and females. The CCCM models constructed using the metabonomics analysis demonstrate that S. thunbergii males and females exhibit obvious gender differences in their responses to UV-B radiation, providing us with a new understanding of the macroalgal gender differences under UV-B radiation, as past investigations always underestimated their diecious characteristics.
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Affiliation(s)
- Yan Sun
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Yu Zang
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China
| | - Jun Chen
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Shuai Shang
- College of Biological and Environmental Engineering, Binzhou University, Binzhou, China
| | - Jing Wang
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Qian Liu
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xuexi Tang
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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7
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Ustynyuk LY, Tikhonov AN. Plastoquinol Oxidation: Rate-Limiting Stage in the Electron Transport Chain of Chloroplasts. BIOCHEMISTRY (MOSCOW) 2022; 87:1084-1097. [DOI: 10.1134/s0006297922100029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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8
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Melkikh AV, Sutormina MI. From leaves to roots: Biophysical models of transport of substances in plants. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2022; 169-170:53-83. [PMID: 35114180 DOI: 10.1016/j.pbiomolbio.2022.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/25/2022] [Accepted: 01/27/2022] [Indexed: 12/19/2022]
Abstract
The transport processes of substances in various plant tissues are extremely diverse. However, models aimed at elucidating the mechanisms of such processes are almost absent in the literature. A unified view of all these transport processes is necessary, considering the laws of statistical physics and thermodynamics. A model of active ion transport was constructed based on the laws of statistical physics. Using this model, we traced the entire pathway of substances and energy in a plant. The pathway included aspects of the production of energy in the process of photosynthesis, consumption of energy to obtain nutrients from the soil, transport of such substances to the main organelles of all types of plant cells, the rise of water with dissolved substances along the trunk to the leaves, and the evaporation of water, accompanied by a change in the percentage of isotopes caused by different rates of evaporation. Models of ion transport in the chloroplasts and mitochondria of plant cells have been constructed. A generalized model comprising plant cells and their vacuoles was analyzed. A model of the transport of substances in the roots of plants was also developed. Based on this model, the problem of transport of substances in tall trees has been considered. The calculated concentrations of ions in the vacuoles of cells and resting potentials agreed well with the experimental data.
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Affiliation(s)
- A V Melkikh
- Ural Federal University, Yekaterinburg, Russia.
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9
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Arzac MI, Fernández-Marín B, García-Plazaola JI. More than just lipid balls: quantitative analysis of plastoglobule attributes and their stress-related responses. PLANTA 2022; 255:62. [PMID: 35141783 PMCID: PMC8828631 DOI: 10.1007/s00425-022-03848-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 01/28/2022] [Indexed: 05/15/2023]
Abstract
Plastoglobules are ubiquitous under non-stress conditions and their morphology, closely related to their composition, changes differently depending on the specific stress that the plant undergoes. Plastoglobules are lipoprotein structures attached to thylakoid membranes, which participate in chloroplast metabolism and stress responses. Their structure contains a coating lipid monolayer and a hydrophobic core that differ in composition. Their function in chloroplasts has been studied focussing on their composition. However, we currently lack a comprehensive study that quantitatively evaluates the occurrence and morphology of plastoglobules. Following a literature search strategy, we quantified the main morphological attributes of plastoglobules from photosynthetic chloroplasts of more than 1000 TEM images published over the last 53 years, covering more than 100 taxa and 15 stress types. The analysis shows that plastoglobules under non-stress conditions are spherical, with an average diameter of 100-200 nm and cover less than 3% of the chloroplast cross-section area. This percentage rises under almost every type of stress, particularly in senescence. Interestingly, an apparent trade-off between increasing either the number or the diameter of plastoglobules governs this response. Our results show that plastoglobules are ubiquitous in chloroplasts of higher plants under non-stress conditions. Besides, provided the specific molecular composition of the core and coat of plastoglobules, we conclude that specific stress-related variation in plastoglobules attributes may allow inferring precise responses of the chloroplast metabolism.
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Affiliation(s)
- Miren I. Arzac
- Department Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - Beatriz Fernández-Marín
- Department Botany, Ecology and Plant Physiology, University of La Laguna (ULL), 38200 Tenerife, Spain
| | - José I. García-Plazaola
- Department Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
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10
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Zhu D, Xiong H, Wu J, Zheng C, Lu D, Zhang L, Xu X. Protein Targeting Into the Thylakoid Membrane Through Different Pathways. Front Physiol 2022; 12:802057. [PMID: 35095563 PMCID: PMC8790069 DOI: 10.3389/fphys.2021.802057] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/07/2021] [Indexed: 01/19/2023] Open
Abstract
In higher plants, chloroplasts are essential semi-autonomous organelles with complex compartments. As part of these sub-organellar compartments, the sheet-like thylakoid membranes contain abundant light-absorbing chlorophylls bound to the light-harvesting proteins and to some of the reaction center proteins. About half of the thylakoid membrane proteins are encoded by nuclear genes and synthesized in the cytosol as precursors before being imported into the chloroplast. After translocation across the chloroplast envelope by the Toc/Tic system, these proteins are subsequently inserted into or translocated across the thylakoid membranes through distinct pathways. The other half of thylakoid proteins are encoded by the chloroplast genome, synthesized in the stroma and integrated into the thylakoid through a cotranslational process. Much progress has been made in identification and functional characterization of new factors involved in protein targeting into the thylakoids, and new insights into this process have been gained. In this review, we introduce the distinct transport systems mediating the translocation of substrate proteins from chloroplast stroma to the thylakoid membrane, and present the recent advances in the identification of novel components mediating these pathways. Finally, we raise some unanswered questions involved in the targeting of chloroplast proteins into the thylakoid membrane, along with perspectives for future research.
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Affiliation(s)
- Dan Zhu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Haibo Xiong
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Jianghao Wu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Canhui Zheng
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Dandan Lu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Lixin Zhang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Xiumei Xu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
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11
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Nozue H, Shigarami T, Fukuda S, Chino T, Saruta R, Shirai K, Nozue M, Kumazaki S. Growth-phase dependent morphological alteration in higher plant thylakoid is accompanied by changes in both photodamage and repair rates. PHYSIOLOGIA PLANTARUM 2021; 172:1983-1996. [PMID: 33786842 DOI: 10.1111/ppl.13408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 02/18/2021] [Accepted: 03/23/2021] [Indexed: 06/12/2023]
Abstract
Thylakoid membranes of young leaves consist of grana and stroma lamellae (stroma-grana [SG] structure). The SG thylakoid is gradually converted into isolated grana (IG), almost lacking the stroma lamellae during growth. This morphological alteration was found to cause a reduction in maximum photosynthetic rate and an enhancement of photoinhibition in photosystem II (PSII). In situ microspectrometric measurements of chlorophyll fluorescence in individual chloroplasts suggested an increase of the PSII/PSI ratio in IG thylakoids of mature leaves. Western blot analysis of isolated IG thylakoids showed relative increases in some PSII components, including the core protein (D1) and light-harvesting components CP24 and Lhcb2. Notably, a nonphotochemical quenching-related factor in the PSII supercomplex, PsbS, decreased by 40%. Changes in the high light response of PSII were detected through parameters of pulse-amplitude modulation fluorometry. Chlorophyll fluorescence lifetime indicated an increase of fluorescence quantum yield in IG. A minimal photodamage-repair rate analysis on a lincomycin treatment of the leaves indicated that repair rate constant of IG is slower than that of SG, while photodamage rate of IG is higher than that of SG. These results suggest that IG thylakoids are relatively sensitive to high light, which is not only due to a higher photodamage rate caused by some rearrangements of PS complexes, but also to the retarded PSII repair that may result from the lack of stroma lamellae. The IG thylakoids found among many plant species thus seem to be an adaptive form to low light environments, although their physiological roles still remain unclear.
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Affiliation(s)
- Hatsumi Nozue
- Research Center for Advanced Plant Factory (SU-PLAF), Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan
| | - Takashi Shigarami
- Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan
| | - Shinji Fukuda
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Takayuki Chino
- Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan
| | - Ryouta Saruta
- Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan
| | - Kana Shirai
- Research Center for Advanced Plant Factory (SU-PLAF), Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan
| | - Masayuki Nozue
- Research Center for Advanced Plant Factory (SU-PLAF), Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan
- Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan
| | - Shigeichi Kumazaki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan
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12
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Barros Junior UO, Lima MDR, Alsahli AA, Lobato AKS. Unraveling the roles of brassinosteroids in alleviating drought stress in young Eucalyptus urophylla plants: Implications on redox homeostasis and photosynthetic apparatus. PHYSIOLOGIA PLANTARUM 2021; 172:748-761. [PMID: 33247448 DOI: 10.1111/ppl.13291] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 11/20/2020] [Accepted: 11/24/2020] [Indexed: 05/20/2023]
Abstract
Water deficit is the most limiting abiotic stress to plants because it affects several physiological and biochemical processes. Brassinosteroids, including 24-epibrassinolide (EBR), are steroids that regulate growth and positively act on gas exchange. This research aims to determine whether EBR can attenuate the negative effects of water deficit, revealing possible contributions of this steroid on photosynthetic machinery of young Eucalyptus urophylla plants under water deficit. The experiment had a completely randomized factorial design with two water conditions (control and water deficit) and three levels of EBR (0, 50, and 100 nM EBR). Water deficit caused a decrease in the levels of total chlorophyll and carotenoids, but these photosynthetic pigments increased by 135 and 226%, respectively, in plants sprayed with EBR when compared to the water deficit + 0 nM EBR treatment. Regarding the antioxidant system, 100 nM EBR induced significant increments in superoxide dismutase (42%), catalase (52%), ascorbate peroxidase (147%), and peroxidase (204%). Steroid application in E. urophylla plants exposed to water deficit increased the effective quantum yield of the photosystem II (PSII) photochemistry and electron transport rate. However, interestingly, it decreased the nonphotochemical quenching and relative energy excess at the PSII level, indicating improvements related to PSII efficiency. This research revealed that application of 100 nM EBR attenuated the negative effects caused by water deficit, being explained by the positive repercussions on antioxidant enzyme activities, chloroplastic pigments, PSII efficiency, electron flux, and net photosynthetic rate.
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Affiliation(s)
- Udson O Barros Junior
- Núcleo de Pesquisa Vegetal Básica e Aplicada, Universidade Federal Rural da Amazônia, Paragominas, Pará, Brazil
| | - Michael D R Lima
- Núcleo de Pesquisa Vegetal Básica e Aplicada, Universidade Federal Rural da Amazônia, Paragominas, Pará, Brazil
| | - Abdulaziz A Alsahli
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Allan K S Lobato
- Núcleo de Pesquisa Vegetal Básica e Aplicada, Universidade Federal Rural da Amazônia, Paragominas, Pará, Brazil
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13
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Vershubskii AV, Tikhonov AN. Structural and Functional Aspects of Electron Transport Thermoregulation and ATP Synthesis in Chloroplasts. BIOCHEMISTRY (MOSCOW) 2021; 86:92-104. [PMID: 33705285 DOI: 10.1134/s0006297921010090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The review is focused on analysis of the mechanisms of temperature-dependent regulation of electron transport and ATP synthesis in chloroplasts of higher plants. Importance of photosynthesis thermoregulation is determined by the fact that plants are ectothermic organisms, whose own temperature depends on the ambient temperature. The review discusses the effects of temperature on the following processes in thylakoid membranes: (i) photosystem 2 activity and plastoquinone reduction; (ii) electron transfer from plastoquinol (via the cytochrome b6f complex and plastocyanin) to photosystem 1; (iii) transmembrane proton transfer; and (iv) ATP synthesis. The data on the relationship between the functional properties of chloroplasts (photosynthetic transfer of electrons and protons, functioning of ATP synthase) and structural characteristics of membrane lipids (fluidity) obtained by electron paramagnetic resonance studies are presented.
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14
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Nishimura K, Nakagawa R, Hachisuga C, Nakajima Munekage Y. Deciphering the Proteotoxic Stress Responses Triggered by the Perturbed Thylakoid Proteostasis in Arabidopsis. PLANTS 2021; 10:plants10030519. [PMID: 33802194 PMCID: PMC8001255 DOI: 10.3390/plants10030519] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 11/30/2022]
Abstract
Here, we explored heat dependent thylakoid FtsH protease substrates and investigated proteotoxicity induced by thermal damage and processive protease dysfunction on the thylakoid membrane. Through our thylakoid enriched proteome analysis and biochemical experiments, carbonylated stromal proteins were suggested as possible FtsH targets. Furthermore, we observed in the thylakoid fractions in the absence of FtsH stromal reactive oxygen species-detoxifying enzymes, as well as heat shock proteins and chaperones, which are known to be upregulated at the transcriptional level when this protease is absent, which is called the damaged protein response, resembling unfolded protein response in eukaryotic cells. Interestingly, the thylakoid-enriched high-density fractions included stromal translation factors and RNA-binding proteins, along with aminoacyl-tRNA synthetase, reminiscent of the formation of stress granules. Unexpectedly, extraplastid proteins such as mitochondrial chaperones, peroxidase, tricarboxylic acid cycle and respiratory chain enzymes, as well as cytosolic ribosomes, translation factors, heat shock proteins, antioxidants and metabolic enzymes, were also found deposited in the high-density fractions depending on the loss of thylakoid FtsH, with more prominent effects of thermal stress on the cytosolic proteins. This may reflect intracellular adaptation to the proteotoxic influences from the organelle.
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Affiliation(s)
- Kenji Nishimura
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda 669-1337, Hyogo, Japan; (C.H.); (Y.N.M.)
- Correspondence: ; Tel.: +81-79-565-7351
| | - Reiko Nakagawa
- Laboratory for Phyloinformatics in RIKEN Center for Biosystems Dynamics Research (BDR), Kobe 650-0047, Hyogo, Japan;
| | - Chisato Hachisuga
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda 669-1337, Hyogo, Japan; (C.H.); (Y.N.M.)
| | - Yuri Nakajima Munekage
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda 669-1337, Hyogo, Japan; (C.H.); (Y.N.M.)
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15
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Applications of reticular diversity in metal–organic frameworks: An ever-evolving state of the art. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2020.213655] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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16
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Anand A, Pandi G. Noncoding RNA: An Insight into Chloroplast and Mitochondrial Gene Expressions. Life (Basel) 2021; 11:life11010049. [PMID: 33450961 PMCID: PMC7828403 DOI: 10.3390/life11010049] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 12/28/2020] [Accepted: 01/05/2021] [Indexed: 12/22/2022] Open
Abstract
Regulation of gene expression in any biological system is a complex process with many checkpoints at the transcriptional, post-transcriptional and translational levels. The control mechanism is mediated by various protein factors, secondary metabolites and a newly included regulatory member, i.e., noncoding RNAs (ncRNAs). It is known that ncRNAs modulate the mRNA or protein profiles of the cell depending on the degree of complementary and context of the microenvironment. In plants, ncRNAs are essential for growth and development in normal conditions by controlling various gene expressions and have emerged as a key player to guard plants during adverse conditions. In order to have smooth functioning of the plants under any environmental pressure, two very important DNA-harboring semi-autonomous organelles, namely, chloroplasts and mitochondria, are considered as main players. These organelles conduct the most crucial metabolic pathways that are required to maintain cell homeostasis. Thus, it is imperative to explore and envisage the molecular machineries responsible for gene regulation within the organelles and their coordination with nuclear transcripts. Therefore, the present review mainly focuses on ncRNAs origination and their gene regulation in chloroplasts and plant mitochondria.
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Affiliation(s)
- Asha Anand
- Correspondence: (A.A.); (G.P.); Tel.: +91-452-245-8230 (G.P.)
| | - Gopal Pandi
- Correspondence: (A.A.); (G.P.); Tel.: +91-452-245-8230 (G.P.)
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17
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Rantala M, Rantala S, Aro EM. Composition, phosphorylation and dynamic organization of photosynthetic protein complexes in plant thylakoid membrane. Photochem Photobiol Sci 2021; 19:604-619. [PMID: 32297616 DOI: 10.1039/d0pp00025f] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The photosystems (PS), catalyzing the photosynthetic reactions of higher plants, are unevenly distributed in the thylakoid membrane: PSII, together with its light harvesting complex (LHC)II, is enriched in the appressed grana stacks, while PSI-LHCI resides in the non-appressed stroma thylakoids, which wind around the grana stacks. The two photosystems interact in a third membrane domain, the grana margins, which connect the grana and stroma thylakoids and allow the loosely bound LHCII to serve as an additional antenna for PSI. The light harvesting is balanced by reversible phosphorylation of LHCII proteins. Nevertheless, light energy also damages PSII and the repair process is regulated by reversible phosphorylation of PSII core proteins. Here, we discuss the detailed composition and organization of PSII-LHCII and PSI-LHCI (super)complexes in the thylakoid membrane of angiosperm chloroplasts and address the role of thylakoid protein phosphorylation in dynamics of the entire protein complex network of the photosynthetic membrane. Finally, we scrutinize the phosphorylation-dependent dynamics of the protein complexes in context of thylakoid ultrastructure and present a model on the reorganization of the entire thylakoid network in response to changes in thylakoid protein phosphorylation.
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Affiliation(s)
- Marjaana Rantala
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520, Turku, Finland
| | - Sanna Rantala
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520, Turku, Finland
| | - Eva-Mari Aro
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520, Turku, Finland.
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18
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Tikhonov AN, Vershubskii AV. Temperature-dependent regulation of electron transport and ATP synthesis in chloroplasts in vitro and in silico. PHOTOSYNTHESIS RESEARCH 2020; 146:299-329. [PMID: 32780309 DOI: 10.1007/s11120-020-00777-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/21/2020] [Indexed: 06/11/2023]
Abstract
The significance of temperature-dependent regulation of photosynthetic apparatus (PSA) is determined by the fact that plant temperature changes with environmental temperature. In this work, we present a brief overview of temperature-dependent regulation of photosynthetic processes in class B chloroplasts (thylakoids) and analyze these processes using a computer model that takes into account the key stages of electron and proton transport coupled to ATP synthesis. The rate constants of partial reactions were parametrized on the basis of experimental temperature dependences of partial photosynthetic processes: (1) photosystem II (PSII) turnover and plastoquinone (PQ) reduction, (2) the plastoquinol (PQH2) oxidation by the cytochrome (Cyt) b6f complex, (3) the ATP synthase activity, and (4) the proton leak from the thylakoid lumen. We consider that PQH2 oxidation is the rate-limiting step in the intersystem electron transport. The parametrization of the rate constants of these processes is based on earlier experimental data demonstrating strong correlations between the functional and structural properties of thylakoid membranes that were probed with the lipid-soluble spin labels embedded into the membranes. Within the framework of our model, we could adequately describe a number of experimental temperature dependences of photosynthetic reactions in thylakoids. Computer modeling of electron and proton transport coupled to ATP synthesis supports the notion that PQH2 oxidation by the Cyt b6f complex and proton pumping into the lumen are the basic temperature-dependent processes that determine the overall electron flux from PSII to molecular oxygen and the net ATP synthesis upon variations of temperature. The model describes two branches of the temperature dependence of the post-illumination reduction of [Formula: see text] characterized by different activation energies (about 60 and ≤ 3.5 kJ mol-1). The model predicts the bell-like temperature dependence of ATP formation, which arises from the balance of several factors: (1) the thermo-induced acceleration of electron transport through the Cyt b6f complex, (2) deactivation of PSII photochemistry at sufficiently high temperatures, and (3) acceleration of the passive proton outflow from the thylakoid lumen bypassing the ATP synthase complex. The model describes the temperature dependence of experimentally measured parameter P/2e, determined as the ratio between the rates of ATP synthesis and pseudocyclic electron transport (H2O → PSII → PSI → O2).
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Affiliation(s)
- Alexander N Tikhonov
- Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russia.
- N.M. Emanuel Institute of Biochemical Physics of Russian Academy of Sciences, Moscow, Russia.
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19
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Staehelin LA, Paolillo DJ. A brief history of how microscopic studies led to the elucidation of the 3D architecture and macromolecular organization of higher plant thylakoids. PHOTOSYNTHESIS RESEARCH 2020; 145:237-258. [PMID: 33017036 PMCID: PMC7541383 DOI: 10.1007/s11120-020-00782-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 08/28/2020] [Indexed: 05/30/2023]
Abstract
Microscopic studies of chloroplasts can be traced back to the year 1678 when Antonie van Leeuwenhoek reported to the Royal Society in London that he saw green globules in grass leaf cells with his single-lens microscope. Since then, microscopic studies have continued to contribute critical insights into the complex architecture of chloroplast membranes and how their structure relates to function. This review is organized into three chronological sections: During the classic light microscope period (1678-1940), the development of improved microscopes led to the identification of green grana, a colorless stroma, and a membrane envelope. More recent (1990-2020) chloroplast dynamic studies have benefited from laser confocal and 3D-structured illumination microscopy. The development of the transmission electron microscope (1940-2000) and thin sectioning techniques demonstrated that grana consist of stacks of closely appressed grana thylakoids interconnected by non-appressed stroma thylakoids. When the stroma thylakoids were shown to spiral around the grana stacks as multiple right-handed helices, it was confirmed that the membranes of a chloroplast are all interconnected. Freeze-fracture and freeze-etch methods verified the helical nature of the stroma thylakoids, while also providing precise information on how the electron transport chain and ATP synthase complexes are non-randomly distributed between grana and stroma membrane regions. The last section (2000-2020) focuses on the most recent discoveries made possible by atomic force microscopy of hydrated membranes, and electron tomography and cryo-electron tomography of cryofixed thylakoids. These investigations have provided novel insights into thylakoid architecture and plastoglobules (summarized in a new thylakoid model), while also producing molecular-scale views of grana and stroma thylakoids in which individual functional complexes can be identified.
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Affiliation(s)
- L Andrew Staehelin
- Department of Molecular, Cellular and Developmental Biology, UCB 347, University of Colorado, Boulder, CO, 80309-0347, USA.
| | - Dominick J Paolillo
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
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20
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Plastocyanin is the long-range electron carrier between photosystem II and photosystem I in plants. Proc Natl Acad Sci U S A 2020; 117:15354-15362. [PMID: 32541018 DOI: 10.1073/pnas.2005832117] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In photosynthetic electron transport, large multiprotein complexes are connected by small diffusible electron carriers, the mobility of which is challenged by macromolecular crowding. For thylakoid membranes of higher plants, a long-standing question has been which of the two mobile electron carriers, plastoquinone or plastocyanin, mediates electron transport from stacked grana thylakoids where photosystem II (PSII) is localized to distant unstacked regions of the thylakoids that harbor PSI. Here, we confirm that plastocyanin is the long-range electron carrier by employing mutants with different grana diameters. Furthermore, our results explain why higher plants have a narrow range of grana diameters since a larger diffusion distance for plastocyanin would jeopardize the efficiency of electron transport. In the light of recent findings that the lumen of thylakoids, which forms the diffusion space of plastocyanin, undergoes dynamic swelling/shrinkage, this study demonstrates that plastocyanin diffusion is a crucial regulatory element of plant photosynthetic electron transport.
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21
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Wietrzynski W, Schaffer M, Tegunov D, Albert S, Kanazawa A, Plitzko JM, Baumeister W, Engel BD. Charting the native architecture of Chlamydomonas thylakoid membranes with single-molecule precision. eLife 2020; 9:53740. [PMID: 32297859 PMCID: PMC7164959 DOI: 10.7554/elife.53740] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 04/03/2020] [Indexed: 12/18/2022] Open
Abstract
Thylakoid membranes scaffold an assortment of large protein complexes that work together to harness the energy of light. It has been a longstanding challenge to visualize how the intricate thylakoid network organizes these protein complexes to finely tune the photosynthetic reactions. Previously, we used in situ cryo-electron tomography to reveal the native architecture of thylakoid membranes (Engel et al., 2015). Here, we leverage technical advances to resolve the individual protein complexes within these membranes. Combined with a new method to visualize membrane surface topology, we map the molecular landscapes of thylakoid membranes inside green algae cells. Our tomograms provide insights into the molecular forces that drive thylakoid stacking and reveal that photosystems I and II are strictly segregated at the borders between appressed and non-appressed membrane domains. This new approach to charting thylakoid topology lays the foundation for dissecting photosynthetic regulation at the level of single protein complexes within the cell.
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Affiliation(s)
- Wojciech Wietrzynski
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, Neuherberg, Germany.,Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Miroslava Schaffer
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Dimitry Tegunov
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Sahradha Albert
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Atsuko Kanazawa
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, United States
| | - Jürgen M Plitzko
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Benjamin D Engel
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, Neuherberg, Germany.,Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
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22
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Mai KKK, Gao P, Kang BH. Electron Microscopy Views of Dimorphic Chloroplasts in C4 Plants. FRONTIERS IN PLANT SCIENCE 2020; 11:1020. [PMID: 32719711 PMCID: PMC7350421 DOI: 10.3389/fpls.2020.01020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 06/22/2020] [Indexed: 05/02/2023]
Abstract
C4 plants enhance photosynthesis efficiency by concentrating CO2 to the site of Rubisco action. Chloroplasts in C4 plants exhibit structural dimorphism because thylakoid architectures vary depending on energy requirements. Advances in electron microscopy imaging capacity and sample preparation technologies allowed characterization of thylakoid structures and their macromolecular arrangements with unprecedented precision mostly in C3 plants. The thylakoid is assembled during chloroplast biogenesis through collaboration between the plastid and nuclear genomes. Recently, the membrane dynamics involved in the assembly process has been investigated with 3D electron microscopy, and molecular factors required for thylakoid construction have been characterized. The two classes of chloroplasts in C4 plants arise from common precursors, but little is known about how a single type of chloroplasts grow, divide, and differentiate to mature into distinct chloroplasts. Here, we outline the thylakoid structure and its assembly processes in C3 plants to discuss ultrastructural analyses of dimorphic chloroplast biogenesis in C4 plant species. Future directions for electron microscopy research of C4 photosynthetic systems are also proposed.
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23
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Bussi Y, Shimoni E, Weiner A, Kapon R, Charuvi D, Nevo R, Efrati E, Reich Z. Fundamental helical geometry consolidates the plant photosynthetic membrane. Proc Natl Acad Sci U S A 2019; 116:22366-22375. [PMID: 31611387 PMCID: PMC6825288 DOI: 10.1073/pnas.1905994116] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Plant photosynthetic (thylakoid) membranes are organized into complex networks that are differentiated into 2 distinct morphological and functional domains called grana and stroma lamellae. How the 2 domains join to form a continuous lamellar system has been the subject of numerous studies since the mid-1950s. Using different electron tomography techniques, we found that the grana and stroma lamellae are connected by an array of pitch-balanced right- and left-handed helical membrane surfaces of different radii and pitch. Consistent with theoretical predictions, this arrangement is shown to minimize the surface and bending energies of the membranes. Related configurations were proposed to be present in the rough endoplasmic reticulum and in dense nuclear matter phases theorized to exist in neutron star crusts, where the right- and left-handed helical elements differ only in their handedness. Pitch-balanced helical elements of alternating handedness may thus constitute a fundamental geometry for the efficient packing of connected layers or sheets.
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Affiliation(s)
- Yuval Bussi
- Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
- Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Eyal Shimoni
- Department of Chemical Research Support, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Allon Weiner
- Centre d'Immunologie et des Maladies Infectieuses, Cimi-Paris, INSERM, Sorbonne Université, 75013 Paris, France
| | - Ruti Kapon
- Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Dana Charuvi
- Institute of Plant Sciences, Agricultural Research Organization - Volcani Center, 7505101 Rishon LeZion, Israel
| | - Reinat Nevo
- Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Efi Efrati
- Department of Physics of Complex Systems, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Ziv Reich
- Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel;
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24
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Macroorganisation and flexibility of thylakoid membranes. Biochem J 2019; 476:2981-3018. [DOI: 10.1042/bcj20190080] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 09/19/2019] [Accepted: 10/03/2019] [Indexed: 02/07/2023]
Abstract
Abstract
The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.
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25
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Gacek DA, Holleboom C, Tietz S, Kirchhoff H, Walla PJ. PsbS‐dependent and ‐independent mechanisms regulate carotenoid‐chlorophyll energy coupling in grana thylakoids. FEBS Lett 2019; 593:3190-3197. [DOI: 10.1002/1873-3468.13586] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/18/2019] [Accepted: 08/05/2019] [Indexed: 01/26/2023]
Affiliation(s)
- Daniel A. Gacek
- Department of Biophysical Chemistry Institute for Physical and Theoretical Chemistry Technische Universität Braunschweig Germany
| | - Christoph‐Peter Holleboom
- Department of Biophysical Chemistry Institute for Physical and Theoretical Chemistry Technische Universität Braunschweig Germany
| | - Stefanie Tietz
- Institute of Biological Chemistry Washington State University Pullman WA USA
- DOE Plant Research Laboratory Michigan State University East Lansing MI USA
| | - Helmut Kirchhoff
- Institute of Biological Chemistry Washington State University Pullman WA USA
| | - Peter Jomo Walla
- Department of Biophysical Chemistry Institute for Physical and Theoretical Chemistry Technische Universität Braunschweig Germany
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26
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Kirchhoff H. Chloroplast ultrastructure in plants. THE NEW PHYTOLOGIST 2019; 223:565-574. [PMID: 30721547 DOI: 10.1111/nph.15730] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 01/25/2019] [Indexed: 05/23/2023]
Abstract
The chloroplast organelle in mesophyll cells of higher plants represents a sunlight-driven metabolic factory that eventually fuels life on our planet. Knowledge of the ultrastructure and the dynamics of this unique organelle is essential to understanding its function in an ever-changing and challenging environment. Recent technological developments promise unprecedented insights into chloroplast architecture and its functionality. The review highlights these new methodical approaches and provides structural models based on recent findings about the plasticity of the thylakoid membrane system in response to different light regimes. Furthermore, the potential role of the lipid droplets plastoglobuli is discussed. It is emphasized that detailed structural insights are necessary on different levels ranging from molecules to entire membrane systems for a holistic understanding of chloroplast function.
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Affiliation(s)
- Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, WA, 99164-6340, USA
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27
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Suslichenko IS, Tikhonov AN. Photo-reducible plastoquinone pools in chloroplasts of Tradescentia plants acclimated to high and low light. FEBS Lett 2019; 593:788-798. [PMID: 30896038 DOI: 10.1002/1873-3468.13366] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 02/28/2019] [Accepted: 03/19/2019] [Indexed: 11/09/2022]
Abstract
In photosynthetic systems of oxygenic type, plastoquinone (PQ) molecules are reduced by photosystem II (PSII). The turnover of PQ determines the rate of PSII operation. PQ molecules are present in surplus with respect to PSII. In this work, using the pulse amplitude modulation-fluorometry technique, we quantified photo-reducible PQ pools in chloroplasts of two contrasting ecotypes of Tradescantia, acclimated either to low light (~ 100 μmol photons·m-2 ·s-1 , LL) or to high light (~ 1000 μmol photons·m-2 ·s-1 , HL). The LL-grown plants are characterized by higher capacity of rapidly reducible PQ pool ([PQ]0 /[PSII] ≈ 8) as compared to HL-grown plants of both species ([PQ]0 /[PSII] ≈ 4). The elevated content of PQ in LL plants favours photosynthetic electron flow at low-solar irradiance.
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Affiliation(s)
| | - Alexander N Tikhonov
- Faculty of Physics, M.V.Lomonosov Moscow State University, Russia.,N.M.Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
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28
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Foshati S, Ekramzadeh M. Thylakoids: A Novel Food-Derived Supplement for Obesity - A Mini-Review. INT J VITAM NUTR RES 2019; 90:169-178. [PMID: 30829138 DOI: 10.1024/0300-9831/a000556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nowadays, overweight and obesity are major epidemic health problems that can bring about some other health issues such as cardiovascular disease which is the first cause of mortality worldwide. Thylakoids are disc-like membranes responsible for photosynthetic light reactions in chloroplasts of green plants. Although only a few animal and human studies have been conducted regarding the impact of thylakoids on overweight- and obesity-related factors, all of them have resulted in positive outcomes. These outcomes are as follows: increment of satiety response; suppression of hunger sensations, particularly hedonic hunger; reduction of body weight and fat; promotion of glucose homeostasis; decrease in serum lipids; attenuation of oxidative stress and inflammation; and modulation of gut microbiota, notably by increasing some helpful bacteria such as Lactobacillus reuteri. It seems that some of these useful effects are related to retarded absorption of dietary fat and carbohydrate caused by thylakoids. There is still a need for more well-designed studies.
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Affiliation(s)
- Sahar Foshati
- Nutrition and Food Sciences Research Center, Department of Clinical Nutrition, School of Nutrition and Food Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Maryam Ekramzadeh
- Nutrition and Food Sciences Research Center, Department of Clinical Nutrition, School of Nutrition and Food Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
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29
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Rea G, Antonacci A, Lambreva MD, Mattoo AK. Features of cues and processes during chloroplast-mediated retrograde signaling in the alga Chlamydomonas. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 272:193-206. [PMID: 29807591 DOI: 10.1016/j.plantsci.2018.04.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/04/2018] [Accepted: 04/23/2018] [Indexed: 06/08/2023]
Abstract
Retrograde signaling is an intracellular communication process defined by cues generated in chloroplast and mitochondria which traverse membranes to their destination in the nucleus in order to regulate nuclear gene expression and protein synthesis. The coding and decoding of such organellar message(s) involve gene medleys and metabolic components about which more is known in higher plants than the unicellular organisms such as algae. Chlamydomonas reinhardtii is an oxygenic microalgal model for genetic and physiological studies. It harbors a single chloroplast and is amenable for generating mutants. The focus of this review is on studies that delineate retrograde signaling in Chlamydomonas vis a vis higher plants. Thus, communication networks between chloroplast and nucleus involving photosynthesis- and ROS-generated signals, functional tetrapyrrole biosynthesis intermediates, and Ca2+-signaling that modulate nuclear gene expression in this alga are discussed. Conceptually, different signaling components converge to regulate either the same or functionally-overlapping gene products.
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Affiliation(s)
- Giuseppina Rea
- Institute of Crystallography, National Research Council of Italy, Via Salaria Km 29, 3 00015 Monterotondo Scalo, Rome, Italy
| | - Amina Antonacci
- Institute of Crystallography, National Research Council of Italy, Via Salaria Km 29, 3 00015 Monterotondo Scalo, Rome, Italy
| | - Maya D Lambreva
- Institute of Crystallography, National Research Council of Italy, Via Salaria Km 29, 3 00015 Monterotondo Scalo, Rome, Italy
| | - Autar K Mattoo
- The Henry A Wallace Agricultural Research Centre, U.S. Department of Agriculture, Sustainable Agricultural Systems Laboratory, Beltsville, MD 20705, USA.
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30
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Gomez MK, Singh J, Acharya P, Jayaprakasha GK, Patil BS. Identification and Quantification of Phytochemicals, Antioxidant Activity, and Bile Acid-Binding Capacity of Garnet Stem Dandelion (Taraxacum officinale). J Food Sci 2018; 83:1569-1578. [PMID: 29802721 DOI: 10.1111/1750-3841.14169] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 03/19/2018] [Accepted: 03/28/2018] [Indexed: 01/19/2023]
Abstract
Dandelion (Taraxacum officinale) var. Garnet Stem was harvested from Texas and New Jersey for identification, quantification of phytochemicals, measurement of free radical scavenging activity, and bile acid binding capacity. The red midrib and petioles were extracted with methanol or ethanol and with or without water in combination with four different acids such as formic, hydrochloric, acetic, and citric acid. LC-ESI-HR-QTOF-MS was used to identify four anthocyanins including cyanidin-3-glucoside, cyanidin-3-(6-malonyl)-glucoside (A-1), cyanidin-3-(6-malonyl)-glucoside (A-2), and peonidin-3-(malonyl)-glucoside for the 1st time. In New Jersey samples, vitamin C and β-carotene were highest in the leaf blades versus whole leaf and petioles. Samples from Texas had highest amount of lutein, violaxanthin, and chlorophyll a and b in leaf blades versus whole leaf and petioles. Maximum DPPH free scavenging activity was found in MeOH: water: acid (80:19:1) and the combination of FA with EtOH: water: acid (80:19:1) demonstrated the higher level of total phenolic. Among six bile acids, sodium chenodeoxycholate was bound maximum in both Texas and New Jersey samples. This is the first report of anthocyanin identification from the midvein and petiole of Garnet Stem dandelion and results suggested that the phytochemicals and nutrients are highest in the leaf but may vary the amount depending on harvest location. PRACTICAL APPLICATION Four anthocyanins in the red midrib and petioles of Garnet Stem could be a potential source for antioxidants and can be used as a source of natural food color.
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Affiliation(s)
- Maricella K Gomez
- Vegetable and Fruit Improvement Center, Dept. of Horticultural Sciences, Texas A&M Univ., 1500 Research Parkway, Suite A120, College Station, TX 77845, U.S.A
| | - Jashbir Singh
- Vegetable and Fruit Improvement Center, Dept. of Horticultural Sciences, Texas A&M Univ., 1500 Research Parkway, Suite A120, College Station, TX 77845, U.S.A
| | - Pratibha Acharya
- Vegetable and Fruit Improvement Center, Dept. of Horticultural Sciences, Texas A&M Univ., 1500 Research Parkway, Suite A120, College Station, TX 77845, U.S.A
| | - G K Jayaprakasha
- Vegetable and Fruit Improvement Center, Dept. of Horticultural Sciences, Texas A&M Univ., 1500 Research Parkway, Suite A120, College Station, TX 77845, U.S.A
| | - Bhimanagouda S Patil
- Vegetable and Fruit Improvement Center, Dept. of Horticultural Sciences, Texas A&M Univ., 1500 Research Parkway, Suite A120, College Station, TX 77845, U.S.A
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Abstract
This chapter presents an overview of structural properties of the cytochrome (Cyt) b 6 f complex and its functioning in chloroplasts. The Cyt b 6 f complex stands at the crossroad of photosynthetic electron transport pathways, providing connectivity between Photosystem (PSI) and Photosysten II (PSII) and pumping protons across the membrane into the thylakoid lumen. After a brief review of the chloroplast electron transport chain, the consideration is focused on the structural organization of the Cyt b 6 f complex and its interaction with plastoquinol (PQH2, reduced form of plastoquinone), a mediator of electron transfer from PSII to the Cyt b 6 f complex. The processes of PQH2 oxidation by the Cyt b 6 f complex have been considered within the framework of the Mitchell's Q-cycle. The overall rate of the intersystem electron transport is determined by PQH2 turnover at the quinone-binding site Qo of the Cyt b 6 f complex. The rate of PQH2 oxidation is controlled by the intrathylakoid pHin, which value determines the protonation/deprotonation events in the Qo-center. Two other regulatory mechanisms associated with the Cyt b 6 f complex are briefly overviewed: (i) redistribution of electron fluxes between alternative (linear and cyclic) pathways, and (ii) "state transitions" related to redistribution of solar energy between PSI and PSII.
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Affiliation(s)
- Alexander F. Mason
- School of Chemistry, the Australian Centre for Nanomedicine and the ARC Centre of Excellence in Convergent Bio‐Nano Science and TechnologyThe University of New South WalesSydney Australia
| | - Pall Thordarson
- School of Chemistry, the Australian Centre for Nanomedicine and the ARC Centre of Excellence in Convergent Bio‐Nano Science and TechnologyThe University of New South WalesSydney Australia
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Liu K, Yuan C, Zou Q, Xie Z, Yan X. Self-Assembled Zinc/Cystine-Based Chloroplast Mimics Capable of Photoenzymatic Reactions for Sustainable Fuel Synthesis. Angew Chem Int Ed Engl 2017; 56:7876-7880. [DOI: 10.1002/anie.201704678] [Citation(s) in RCA: 163] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Kai Liu
- State Key Laboratory of Biochemical Engineering; Institute of Process Engineering; Chinese Academy of Sciences; 100190 Beijing China
- University of Chinese Academy of Sciences; 100049 Beijing China
| | - Chengqian Yuan
- State Key Laboratory of Biochemical Engineering; Institute of Process Engineering; Chinese Academy of Sciences; 100190 Beijing China
- Center for Mesoscience; Institute of Process Engineering; Chinese Academy of Sciences; 100190 Beijing China
| | - Qianli Zou
- State Key Laboratory of Biochemical Engineering; Institute of Process Engineering; Chinese Academy of Sciences; 100190 Beijing China
| | - Zengchun Xie
- State Key Laboratory of Biochemical Engineering; Institute of Process Engineering; Chinese Academy of Sciences; 100190 Beijing China
| | - Xuehai Yan
- State Key Laboratory of Biochemical Engineering; Institute of Process Engineering; Chinese Academy of Sciences; 100190 Beijing China
- Center for Mesoscience; Institute of Process Engineering; Chinese Academy of Sciences; 100190 Beijing China
- University of Chinese Academy of Sciences; 100049 Beijing China
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35
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Liu K, Yuan C, Zou Q, Xie Z, Yan X. Self-Assembled Zinc/Cystine-Based Chloroplast Mimics Capable of Photoenzymatic Reactions for Sustainable Fuel Synthesis. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201704678] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kai Liu
- State Key Laboratory of Biochemical Engineering; Institute of Process Engineering; Chinese Academy of Sciences; 100190 Beijing China
- University of Chinese Academy of Sciences; 100049 Beijing China
| | - Chengqian Yuan
- State Key Laboratory of Biochemical Engineering; Institute of Process Engineering; Chinese Academy of Sciences; 100190 Beijing China
- Center for Mesoscience; Institute of Process Engineering; Chinese Academy of Sciences; 100190 Beijing China
| | - Qianli Zou
- State Key Laboratory of Biochemical Engineering; Institute of Process Engineering; Chinese Academy of Sciences; 100190 Beijing China
| | - Zengchun Xie
- State Key Laboratory of Biochemical Engineering; Institute of Process Engineering; Chinese Academy of Sciences; 100190 Beijing China
| | - Xuehai Yan
- State Key Laboratory of Biochemical Engineering; Institute of Process Engineering; Chinese Academy of Sciences; 100190 Beijing China
- Center for Mesoscience; Institute of Process Engineering; Chinese Academy of Sciences; 100190 Beijing China
- University of Chinese Academy of Sciences; 100049 Beijing China
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Liu H, Xia Y, Cai W, Zhang Y, Zhang X, Du S. Enantioselective oxidative stress and oxidative damage caused by Rac- and S-metolachlor to Scenedesmus obliquus. CHEMOSPHERE 2017; 173:22-30. [PMID: 28104477 DOI: 10.1016/j.chemosphere.2017.01.028] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 12/07/2016] [Accepted: 01/04/2017] [Indexed: 06/06/2023]
Abstract
The rational use and environmental security of chiral pesticides has gained the interest of many researchers. The enantioselective effects of Rac- and S-metolachlor on oxidative stress in Scenedesmus obliquus were determined in this study. Stronger green fluorescence was observed in response to S-metolachlor treatment than to Rac-metolachlor treatment, suggesting that more reactive oxygen species (ROS) were stimulated by S-metolachlor. ROS levels following S-metolachlor treatment were 1.92-, 8.31-, and 1.08-times higher than those observed following Rac-metolachlor treatment at 0.1, 0.2, and 0.3 mg/L, respectively. Superoxide dismutase (SOD) and catalase (CAT) were stimulated with increasing herbicide concentrations, with S-metolachlor exhibiting a greater effect. Oxidative damage in terms of chlorophyll (Chl) content, cellular membrane permeability, and cellular ultrastructures of S. obliquus were investigated. Chla and Chlb contents in algae treated with Rac-metolachlor were 2-6-fold higher than those in algae treated with S-metolachlor at 0.1, 0.2, and 0.3 mg/L. The cellular membrane permeability of algae exposed to 0.3 mg/L Rac- and S-metolachlor was 6.19- and 42.5-times that of the control. Correlation analysis implied that ROS are the major factor responsible for the oxidative damage caused by Rac- and S-metolachlor. Damage to the chloroplasts and cell membrane of S. obliquus, low production of starch granules, and an increased number of vacuoles were observed upon ultrastructural morphology analysis by transmission electron microscope. These results indicate that S-metolachlor has a greater effect on S. obliquus than Rac-metolachlor.
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Affiliation(s)
- Huijun Liu
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China.
| | - YiLu Xia
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Weidan Cai
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China; Environmental Science Research & Design Institute of Taizhou City, China
| | - Yina Zhang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Xiaoqiang Zhang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Shaoting Du
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China.
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Vershubskii AV, Trubitsin BV, Priklonskii VI, Tikhonov AN. Lateral heterogeneity of the proton potential along the thylakoid membranes of chloroplasts. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:388-401. [DOI: 10.1016/j.bbamem.2016.11.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 11/20/2016] [Accepted: 11/29/2016] [Indexed: 02/06/2023]
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Takemura K, Kamachi H, Kume A, Fujita T, Karahara I, Hanba YT. A hypergravity environment increases chloroplast size, photosynthesis, and plant growth in the moss Physcomitrella patens. JOURNAL OF PLANT RESEARCH 2017; 130:181-192. [PMID: 27896464 PMCID: PMC6105216 DOI: 10.1007/s10265-016-0879-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 10/24/2016] [Indexed: 06/06/2023]
Abstract
The physiological and anatomical responses of bryophytes to altered gravity conditions will provide crucial information for estimating how plant physiological traits have evolved to adapt to significant increases in the effects of gravity in land plant history. We quantified changes in plant growth and photosynthesis in the model plant of mosses, Physcomitrella patens, grown under a hypergravity environment for 25 days or 8 weeks using a custom-built centrifuge equipped with a lighting system. This is the first study to examine the response of bryophytes to hypergravity conditions. Canopy-based plant growth was significantly increased at 10×g, and was strongly affected by increases in plant numbers. Rhizoid lengths for individual gametophores were significantly increased at 10×g. Chloroplast diameters (major axis) and thicknesses (minor axis) in the leaves of P. patens were also increased at 10×g. The area-based photosynthesis rate of P. patens was also enhanced at 10×g. Increases in shoot numbers and chloroplast sizes may elevate the area-based photosynthesis rate under hypergravity conditions. We observed a decrease in leaf cell wall thickness under hypergravity conditions, which is in contrast to previous findings obtained using angiosperms. Since mosses including P. patens live in dense populations, an increase in canopy-based plant numbers may be effective to enhance the toughness of the population, and, thus, represents an effective adaptation strategy to a hypergravity environment for P. patens.
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Affiliation(s)
- Kaori Takemura
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
| | - Hiroyuki Kamachi
- Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan
| | - Atsushi Kume
- Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan
| | - Tomomichi Fujita
- Faculty of Science, Hokkaido University, Kita-ku, Sapporo, 060-0810, Japan
| | - Ichirou Karahara
- Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan
| | - Yuko T Hanba
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan.
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39
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Charuvi D, Nevo R, Kaplan-Ashiri I, Shimoni E, Reich Z. Studying the Supramolecular Organization of Photosynthetic Membranes within Freeze-fractured Leaf Tissues by Cryo-scanning Electron Microscopy. J Vis Exp 2016:54066. [PMID: 27403565 PMCID: PMC4993236 DOI: 10.3791/54066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Cryo-scanning electron microscopy (SEM) of freeze-fractured samples allows investigation of biological structures at near native conditions. Here, we describe a technique for studying the supramolecular organization of photosynthetic (thylakoid) membranes within leaf samples. This is achieved by high-pressure freezing of leaf tissues, freeze-fracturing, double-layer coating and finally cryo-SEM imaging. Use of the double-layer coating method allows acquiring high magnification (>100,000X) images with minimal beam damage to the frozen-hydrated samples as well as minimal charging effects. Using the described procedures we investigated the alterations in supramolecular distribution of photosystem and light-harvesting antenna protein complexes that take place during dehydration of the resurrection plant Craterostigma pumilum, in situ.
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Affiliation(s)
- Dana Charuvi
- Department of Biological Chemistry, Weizmann Institute of Science; Institute of Plant Sciences, Agricultural Research Organization, Volcani Center;
| | - Reinat Nevo
- Department of Biological Chemistry, Weizmann Institute of Science
| | | | - Eyal Shimoni
- Department of Chemical Research Support, Weizmann Institute of Science
| | - Ziv Reich
- Department of Biological Chemistry, Weizmann Institute of Science
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40
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Fingerprinting the macro-organisation of pigment-protein complexes in plant thylakoid membranes in vivo by circular-dichroism spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1479-1489. [PMID: 27154055 DOI: 10.1016/j.bbabio.2016.04.287] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 04/30/2016] [Indexed: 11/24/2022]
Abstract
Macro-organisation of the protein complexes in plant thylakoid membranes plays important roles in the regulation and fine-tuning of photosynthetic activity. These delicate structures might, however, undergo substantial changes during isolating the thylakoid membranes or during sample preparations, e.g., for electron microscopy. Circular-dichroism (CD) spectroscopy is a non-invasive technique which can thus be used on intact samples. Via excitonic and psi-type CD bands, respectively, it carries information on short-range excitonic pigment-pigment interactions and the macro-organisation (chiral macrodomains) of pigment-protein complexes (psi, polymer or salt-induced). In order to obtain more specific information on the origin of the major psi-type CD bands, at around (+)506, (-)674 and (+)690nm, we fingerprinted detached leaves and isolated thylakoid membranes of wild-type and mutant plants and also tested the effects of different environmental conditions in vivo. We show that (i) the chiral macrodomains disassemble upon mild detergent treatments, but not after crosslinking the protein complexes; (ii) in different wild-type leaves of dicotyledonous and monocotyledonous angiosperms the CD features are quite robust, displaying very similar excitonic and psi-type bands, suggesting similar protein composition and (macro-) organisation of photosystem II (PSII) supercomplexes in the grana; (iii) the main positive psi-type bands depend on light-harvesting protein II contents of the membranes; (iv) the (+)506nm band appears only in the presence of PSII-LHCII supercomplexes and does not depend on the xanthophyll composition of the membranes. Hence, CD spectroscopy can be used to detect different macro-domains in the thylakoid membranes with different outer antenna compositions in vivo.
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Ruban AV, Johnson MP. Visualizing the dynamic structure of the plant photosynthetic membrane. NATURE PLANTS 2015; 1:15161. [PMID: 27251532 DOI: 10.1038/nplants.2015.161] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 09/29/2015] [Indexed: 05/28/2023]
Abstract
The chloroplast thylakoid membrane is the site for the initial steps of photosynthesis that convert solar energy into chemical energy, ultimately powering almost all life on earth. The heterogeneous distribution of protein complexes within the membrane gives rise to an intricate three-dimensional structure that is nonetheless extremely dynamic on a timescale of seconds to minutes. These dynamics form the basis for the regulation of photosynthesis, and therefore the adaptability of plants to different environments. High-resolution microscopy has in recent years begun to provide new insights into the structural dynamics underlying a number of regulatory processes such as membrane stacking, photosystem II repair, photoprotective energy dissipation, state transitions and alternative electron transfer. Here we provide an overview of the essentials of thylakoid membrane structure in plants, and consider how recent advances, using a range of microscopies, have substantially increased our knowledge of the thylakoid dynamic structure. We discuss both the successes and limitations of the currently available techniques and highlight newly emerging microscopic methods that promise to move the field beyond the current 'static' view of membrane organization based on frozen snapshots to a 'live' view of functional membranes imaged under native aqueous conditions at ambient temperature and responding dynamically to external stimuli.
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Affiliation(s)
- Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
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42
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Belgio E, Ungerer P, Ruban AV. Light-harvesting superstructures of green plant chloroplasts lacking photosystems. PLANT, CELL & ENVIRONMENT 2015; 38:2035-47. [PMID: 25737144 DOI: 10.1111/pce.12528] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 02/23/2015] [Indexed: 05/26/2023]
Abstract
The light-harvesting antenna of higher plant photosystem II (LHCII) is the major photosynthetic membrane component encoded by an entire family of homologous nuclear genes. On the contrary, the great majority of proteins of photosystems and electron transport components are encoded by the chloroplast genome. In this work, we succeeded in gradually inhibiting the expression of the chloroplast genes that led to the disappearance of the photosystem complexes, mimicking almost total photoinhibition. The treated plants, despite displaying only some early signs of senescence, sustained their metabolism and growth for several weeks. The only major remaining membrane component was LHCII antenna that formed superstructures - stacks of dozens of thylakoids or supergrana. Freeze-fracture electron microscopy revealed specific organization, directly displaying frequently bifurcated membranes with reduced or totally absent photosystem II (PSII) reaction centre complexes. Our findings show that it is possible to accumulate large amounts of light-harvesting membranes, organized into three-dimensional structures, in the absence of reaction centre complexes. This points to the reciprocal role of LHCII and PSII in self-assembly of the three-dimensional matrix of the photosynthetic membrane, dictating its size and flexible adaptation to the light environment.
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Affiliation(s)
- Erica Belgio
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Petra Ungerer
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
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43
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Pérez-Escobar OA, Balbuena JA, Gottschling M. Rumbling Orchids: How To Assess Divergent Evolution Between Chloroplast Endosymbionts and the Nuclear Host. Syst Biol 2015; 65:51-65. [DOI: 10.1093/sysbio/syv070] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 09/15/2015] [Indexed: 01/17/2023] Open
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44
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Larom S, Kallmann D, Saper G, Pinhassi R, Rothschild A, Dotan H, Ankonina G, Schuster G, Adir N. The Photosystem II D1-K238E mutation enhances electrical current production using cyanobacterial thylakoid membranes in a bio-photoelectrochemical cell. PHOTOSYNTHESIS RESEARCH 2015; 126:161-9. [PMID: 25588957 DOI: 10.1007/s11120-015-0075-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 01/02/2015] [Indexed: 05/12/2023]
Abstract
The conversion of solar energy (SEC) to storable chemical energy by photosynthesis has been performed by photosynthetic organisms, including oxygenic cyanobacteria for over 3 billion years. We have previously shown that crude thylakoid membranes from the cyanobacterium Synechocytis sp. PCC 6803 can reduce the electron transfer (ET) protein cytochrome c even in the presence of the PSII inhibitor DCMU. Mutation of lysine 238 of the Photosystem II D1 protein to glutamic acid increased the cytochrome reduction rates, indicating the possible position of this unknown ET pathway. In this contribution, we show that D1-K238E is rather unique, as other mutations to K238, or to other residues in the same vicinity, are not as successful in cytochrome c reduction. This observation indicates the sensitivity of ET reactions to minor changes. As the next step in obtaining useful SEC from biological material, we describe the use of crude Synechocystis membranes in a bio-photovoltaic cell containing an N-acetyl cysteine-modified gold electrode. We show the production of significant current for prolonged time durations, in the presence of DCMU. Surprisingly, the presence of cytochrome c was not found to be necessary for ET to the bio-voltaic cell.
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Affiliation(s)
- Shirley Larom
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Dan Kallmann
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Grand Technion Energy Program, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Faculty of Material Science and Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Gadiel Saper
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Grand Technion Energy Program, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Faculty of Material Science and Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Roy Pinhassi
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Grand Technion Energy Program, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Faculty of Material Science and Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Avner Rothschild
- Faculty of Material Science and Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Hen Dotan
- Faculty of Material Science and Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Guy Ankonina
- Photovoltaics Lab, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Gadi Schuster
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel.
| | - Noam Adir
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel.
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45
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Ware MA, Giovagnetti V, Belgio E, Ruban AV. PsbS protein modulates non-photochemical chlorophyll fluorescence quenching in membranes depleted of photosystems. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 152:301-7. [PMID: 26233261 DOI: 10.1016/j.jphotobiol.2015.07.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 07/22/2015] [Accepted: 07/23/2015] [Indexed: 01/21/2023]
Abstract
Plants with varying levels of PsbS protein were grown on lincomycin. Enhanced levels of non-photochemical fluorescence quenching (NPQ) in over-expressers of the protein have been observed. This was accompanied by increased amplitude of the irreversible NPQ component, qI, previously considered to reflect mainly photoinhibition of PSII reaction centres (RCII). However, since RCIIs were largely absent the observed qI is likely to originate from the LHCII antenna. In chloroplasts of over-expressers of PsbS grown on lincomycin an abnormally large NPQ (∼7) was characterised by a 0.34 ns average chlorophyll fluorescence lifetime. Yet the lifetime in the Fm state was similar to that of wild-type plants. 77K fluorescence emission spectra revealed a specific 700 nm peak typical of LHCII aggregates as well as quenching of the PSI fluorescence at 730 nm. The aggregated state manifested itself as a clear change in the distance between LHCII complexes detected by freeze-fracture electron microscopy. Grana thylakoids in the quenched state revealed 3 times more aggregated LHCII particles compared to the dark-adapted state. Overall, the results directly demonstrate the importance of LHCII aggregation in the NPQ mechanism and show that the PSII supercomplex structure plays no role in formation of the observed quenching.
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Affiliation(s)
- Maxwell A Ware
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Vasco Giovagnetti
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Erica Belgio
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
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46
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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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Engel BD, Schaffer M, Kuhn Cuellar L, Villa E, Plitzko JM, Baumeister W. Native architecture of the Chlamydomonas chloroplast revealed by in situ cryo-electron tomography. eLife 2015; 4. [PMID: 25584625 PMCID: PMC4292175 DOI: 10.7554/elife.04889] [Citation(s) in RCA: 167] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 12/08/2014] [Indexed: 12/19/2022] Open
Abstract
Chloroplast function is orchestrated by the organelle's intricate architecture. By combining cryo-focused ion beam milling of vitreous Chlamydomonas cells with cryo-electron tomography, we acquired three-dimensional structures of the chloroplast in its native state within the cell. Chloroplast envelope inner membrane invaginations were frequently found in close association with thylakoid tips, and the tips of multiple thylakoid stacks converged at dynamic sites on the chloroplast envelope, implicating lipid transport in thylakoid biogenesis. Subtomogram averaging and nearest neighbor analysis revealed that RuBisCO complexes were hexagonally packed within the pyrenoid, with ∼15 nm between their centers. Thylakoid stacks and the pyrenoid were connected by cylindrical pyrenoid tubules, physically bridging the sites of light-dependent photosynthesis and light-independent carbon fixation. Multiple parallel minitubules were bundled within each pyrenoid tubule, possibly serving as conduits for the targeted one-dimensional diffusion of small molecules such as ATP and sugars between the chloroplast stroma and the pyrenoid matrix. DOI:http://dx.doi.org/10.7554/eLife.04889.001 Many organisms can harvest light to produce their own energy through a process called photosynthesis. In plant and algal cells, photosynthesis takes place within the chloroplasts, which are compartments that contain stacks of structures called thylakoids. Inside the thylakoids, proteins absorb energy from light and convert it into biochemical energy that can be used by the cell. This energy then powers a series of reactions that result in carbon dioxide being incorporated into energy-rich sugars. The enzyme RuBisCO is essential for this process, and is believed to be the most abundant protein on Earth. In land plants, RuBisCO is found throughout the chloroplast, but in algae it is limited to a specialized area called the pyrenoid. Much of our current knowledge of chloroplast structure comes from transmission electron microscopy (TEM) images. However, the traditional methods used to prepare cells for TEM can damage their internal structures. Also, previous studies have focused primarily on the chloroplasts of land plants, even though aquatic organisms—including the alga Chlamydomonas—account for over 50% of photosynthesis on the planet. Here, Engel et al. provide the first three-dimensional structures of Chlamydomonas chloroplasts in their natural state. They used several recently-developed techniques to study cells that were preserved in a close-to-living condition. The cells were rapidly frozen, thinned with a technique called cryo-focused ion beam milling, and then imaged by a type of TEM called cryo-electron tomography. The three-dimensional images provide many insights into the Chlamydomonas chloroplast, including evidence that lipids and proteins move between the membrane that surrounds the chloroplast—called the chloroplast envelope—and the tips of the thylakoids. These images show how thylakoids may be built by the transport of molecules from the chloroplast envelope. In addition, the images reveal the detailed structures of the tubes that connect the thylakoids to the pyrenoid, which could explain how the two stages of photosynthesis (light harvesting and the conversion of carbon dioxide) can be coordinated even though they occur at different places within the chloroplast. Engel et al. also observed that RuBisCO enzymes are arranged in a hexagonal pattern inside the pyrenoid, but are spaced too far apart to make direct contact with each other. To understand how the pyrenoid is assembled, a future goal will be to determine what causes RuBisCO to be arranged in this way. DOI:http://dx.doi.org/10.7554/eLife.04889.002
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Affiliation(s)
- Benjamin D Engel
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Miroslava Schaffer
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Luis Kuhn Cuellar
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Elizabeth Villa
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Jürgen M Plitzko
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
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Engel BD, Schaffer M, Kuhn Cuellar L, Villa E, Plitzko JM, Baumeister W. Native architecture of the Chlamydomonas chloroplast revealed by in situ cryo-electron tomography. eLife 2015. [PMID: 25584625 DOI: 10.7554/elife.04889#sthash.yy91intr.dpuf] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Chloroplast function is orchestrated by the organelle's intricate architecture. By combining cryo-focused ion beam milling of vitreous Chlamydomonas cells with cryo-electron tomography, we acquired three-dimensional structures of the chloroplast in its native state within the cell. Chloroplast envelope inner membrane invaginations were frequently found in close association with thylakoid tips, and the tips of multiple thylakoid stacks converged at dynamic sites on the chloroplast envelope, implicating lipid transport in thylakoid biogenesis. Subtomogram averaging and nearest neighbor analysis revealed that RuBisCO complexes were hexagonally packed within the pyrenoid, with ~15 nm between their centers. Thylakoid stacks and the pyrenoid were connected by cylindrical pyrenoid tubules, physically bridging the sites of light-dependent photosynthesis and light-independent carbon fixation. Multiple parallel minitubules were bundled within each pyrenoid tubule, possibly serving as conduits for the targeted one-dimensional diffusion of small molecules such as ATP and sugars between the chloroplast stroma and the pyrenoid matrix.
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Affiliation(s)
- Benjamin D Engel
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Miroslava Schaffer
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Luis Kuhn Cuellar
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Elizabeth Villa
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Jürgen M Plitzko
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
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Brillouet JM. On the Role of Chloroplasts in the Polymerization of Tannins in Tracheophyta: A Monograph. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/ajps.2015.69140] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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50
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Ford RC, Holzenburg A. Organization of protein complexes and a mechanism for grana formation in photosynthetic membranes as revealed by cryo-electron microscopy. CRYSTAL RESEARCH AND TECHNOLOGY 2014. [DOI: 10.1002/crat.201300116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- R. C. Ford
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences; The University of Manchester; Manchester M13 9PT UK
| | - A. Holzenburg
- Microscopy and Imaging Center, Department of Biology, and Department of Biochemistry & Biophysics; Texas A&M University; College Station, TX 77843-2257 USA
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