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Vilyanen D, Pavlov I, Naydov I, Ivanov B, Kozuleva M. Peculiarities of DNP-INT and DBMIB as inhibitors of the photosynthetic electron transport. PHOTOSYNTHESIS RESEARCH 2024; 161:79-92. [PMID: 38108927 DOI: 10.1007/s11120-023-01063-5] [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: 09/30/2023] [Accepted: 11/13/2023] [Indexed: 12/19/2023]
Abstract
Inhibitory analysis is a useful tool for studying cytochrome b6f complex in the photosynthetic electron transport chain. Here, we examine the inhibitory efficiency of two widely used inhibitors of the plastoquinol oxidation in the cytochrome b6f complex, namely 2,4-dinitrophenyl ether of 2-iodo-4-nitrothymol (DNP-INT) and 2,5-dibromo-3-methyl-6-isopropylbenzoquinone (DBMIB). Using isolated thylakoids from pea and arabidopsis, we demonstrate that inhibitory activity of DNP-INT and DBMIB is enhanced by increasing irradiance, and this effect is due to the increase in the rate of electron transport. However, the accumulation of protons in the thylakoid lumen at low light intensity has opposite effects on the inhibitory activity of DNP-INT and DBMIB, namely increasing the activity of DNP-INT and restricting the activity of DBMIB. These results allow for the refinement of the conditions under which the use of these inhibitors leads to the complete inhibition of plastoquinol oxidation in the cytochrome b6f complex, thereby broadening our understanding of the operation of the cytochrome b6f complex under conditions of steady-state electron transport.
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Affiliation(s)
- Daria Vilyanen
- Federal Research Center, Institute of Basic Biological Problems of the Russian Academy of Sciences, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, Russia
| | - Ilya Pavlov
- Saint Petersburg State University, Saint Petersburg, Russia
| | - Ilya Naydov
- Federal Research Center, Institute of Basic Biological Problems of the Russian Academy of Sciences, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, Russia
| | - Boris Ivanov
- Federal Research Center, Institute of Basic Biological Problems of the Russian Academy of Sciences, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, Russia
| | - Marina Kozuleva
- Federal Research Center, Institute of Basic Biological Problems of the Russian Academy of Sciences, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, Russia.
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2
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Li A, You T, Pang X, Wang Y, Tian L, Li X, Liu Z. Structural basis for an early stage of the photosystem II repair cycle in Chlamydomonas reinhardtii. Nat Commun 2024; 15:5211. [PMID: 38890314 PMCID: PMC11189392 DOI: 10.1038/s41467-024-49532-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 06/10/2024] [Indexed: 06/20/2024] Open
Abstract
Photosystem II (PSII) catalyzes water oxidation and plastoquinone reduction by utilizing light energy. It is highly susceptible to photodamage under high-light conditions and the damaged PSII needs to be restored through a process known as the PSII repair cycle. The detailed molecular mechanism underlying the PSII repair process remains mostly elusive. Here, we report biochemical and structural features of a PSII-repair intermediate complex, likely arrested at an early stage of the PSII repair process in the green alga Chlamydomonas reinhardtii. The complex contains three protein factors associated with a damaged PSII core, namely Thylakoid Enriched Factor 14 (TEF14), Photosystem II Repair Factor 1 (PRF1), and Photosystem II Repair Factor 2 (PRF2). TEF14, PRF1 and PRF2 may facilitate the release of the manganese-stabilizing protein PsbO, disassembly of peripheral light-harvesting complexes from PSII and blockage of the QB site, respectively. Moreover, an α-tocopherol quinone molecule is located adjacent to the heme group of cytochrome b559, potentially fulfilling a photoprotective role by preventing the generation of reactive oxygen species.
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Affiliation(s)
- Anjie Li
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Centre for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Tingting You
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, 310024, China
| | - Xiaojie Pang
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Yidi Wang
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Centre for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Lijin Tian
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Xiaobo Li
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, 310024, China.
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, 310024, China.
| | - Zhenfeng Liu
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Centre for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 101408, China.
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3
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Dragoev SG. Lipid Peroxidation in Muscle Foods: Impact on Quality, Safety and Human Health. Foods 2024; 13:797. [PMID: 38472909 DOI: 10.3390/foods13050797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 02/07/2024] [Accepted: 02/13/2024] [Indexed: 03/14/2024] Open
Abstract
The issue of lipid changes in muscle foods under the action of atmospheric oxygen has captured the attention of researchers for over a century. Lipid oxidative processes initiate during the slaughtering of animals and persist throughout subsequent technological processing and storage of the finished product. The oxidation of lipids in muscle foods is a phenomenon extensively deliberated in the scientific community, acknowledged as one of the pivotal factors affecting their quality, safety, and human health. This review delves into the nature of lipid oxidation in muscle foods, highlighting mechanisms of free radical initiation and the propagation of oxidative processes. Special attention is given to the natural antioxidant protective system and dietary factors influencing the stability of muscle lipids. The review traces mechanisms inhibiting oxidative processes, exploring how changes in lipid oxidative substrates, prooxidant activity, and the antioxidant protective system play a role. A critical review of the oxidative stability and safety of meat products is provided. The impact of oxidative processes on the quality of muscle foods, including flavour, aroma, taste, colour, and texture, is scrutinised. Additionally, the review monitors the effect of oxidised muscle foods on human health, particularly in relation to the autooxidation of cholesterol. Associations with coronary cardiovascular disease, brain stroke, and carcinogenesis linked to oxidative stress, and various infections are discussed. Further studies are also needed to formulate appropriate technological solutions to reduce the risk of chemical hazards caused by the initiation and development of lipid peroxidation processes in muscle foods.
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Affiliation(s)
- Stefan G Dragoev
- Department of Meat and Fish Technology, Technological Faculty, University of Food Technologies, 26 Maritza Blvd., 4002 Plovdiv, Bulgaria
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4
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Morales M, Munné-Bosch S. Hormonal response to recurrent seasonal stress in coastal and mountain scabiouses growing in their natural habitat: linking ABA and jasmonates with photoprotection. PHYSIOLOGIA PLANTARUM 2024; 176:e14265. [PMID: 38556740 DOI: 10.1111/ppl.14265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/06/2024] [Accepted: 03/08/2024] [Indexed: 04/02/2024]
Abstract
Plant species distribution across ecosystems is influenced by multiple environmental factors, and recurrent seasonal stress events can act as natural selection agents for specific plant traits and limit species distribution. For that, studies aiming at understanding how environmental constraints affect adaptive mechanisms of taxonomically closely related species are of great interest. We chose two Scabiosa species inhabiting contrasting environments: the coastal scabious S. atropurpurea, typically coping with hot-dry summers in a Mediterranean climate, and the mountain scabious S. columbaria facing cold winters in an oceanic climate. A set of functional traits was examined to assess plant performance in these congeneric species from contrasting natural habitats. Both S. atropurpurea and S. columbaria appeared to be perfectly adapted to their environment in terms of adjustments in stomatal closure, CO2 assimilation rate and water use efficiency over the seasons. However, an unexpected dry period during winter followed by the typical Mediterranean hot-dry summer forced S. atropurpurea plants to deploy a set of photoprotective responses during summer. Aside from reductions in leaf water content and Fv/Fm, photoprotective molecules (carotenoids, α-tocopherol and anthocyanins) per unit of chlorophyll increased, mostly as a consequence of a severe chlorophyll loss. The profiling of stress-related hormones (ABA, salicylic acid and jasmonates) revealed associations between ABA and the bioactive jasmonoyl-isoleucine with the underlying photoprotective response to recurrent seasonal stress in S. atropurpurea. We conclude that jasmonates may be used together with ABA as a functional trait that may, at least in part, help understand plant responses to recurrent seasonal stress in the current frame of global climate change.
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Affiliation(s)
- Melanie Morales
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Universitat de Barcelona, Barcelona, Spain
- Institut de Recerca en Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Spain
| | - Sergi Munné-Bosch
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Universitat de Barcelona, Barcelona, Spain
- Institut de Recerca en Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Spain
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5
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Villadangos S, Munné-Bosch S. Acclimation to a combination of water deficit and nutrient deprivation through simultaneous increases in abscisic acid and bioactive jasmonates in the succulent plant Sempervivum tectorum L. JOURNAL OF PLANT PHYSIOLOGY 2023; 287:154040. [PMID: 37364405 DOI: 10.1016/j.jplph.2023.154040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/12/2023] [Accepted: 06/12/2023] [Indexed: 06/28/2023]
Abstract
Activation of hormonal responses defines the drought acclimation ability of plants and may condition their survival. However, aside ABA, little is known about the possible contribution of other phytohormones, such as jasmonates and salicylates, in the response of CAM plants to water deficit. Here, we aimed to study the physiological mechanisms underlying the stress tolerance of house leek (Sempervivum tectorum L.), a CAM plant adapted to survive harsh environments, to a combination of water deficit and nutrient deprivation. We exposed plants to the combination of these two abiotic stresses by withholding nutrient solution for 10 weeks and monitored their physiological response every two weeks by measuring various stress makers together with the accumulation of stress-related phytohormones and photoprotective molecules, such as tocopherols (vitamin E). Results showed that ABA content increased by 4.2-fold after four weeks of water deficit to keep later constant up to 10 weeks of stress, variations that occurred concomitantly with reductions in the relative leaf water content, which decreased by up to 20% only. The bioactive jasmonate, jasmonoyl-isoleucine was the other stress-related phytohormone that simultaneously increased under stress together with ABA. While contents of salicylic acid and the jasmonoyl-isoleucine precursors, 12-oxo-phytodienoic acid and jasmonic acid decreased with water deficit, those of jasmonoyl-isoleucine increased 3.6-fold at four weeks of stress. The contents of ABA and jasmonoyl-isoleucine correlated positively between them and with the content of α-tocopherol per unit of chlorophyll, thus suggesting a photoprotective activation role. It is concluded that S. tectorum not only withstands a combination of water deficit and nutrient deprivation for 10 weeks without any symptom of damage but also activates effective defense strategies through the simultaneous accumulation of ABA and the bioactive jasmonate form, jasmonoyl-isoleucine.
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Affiliation(s)
- Sabina Villadangos
- Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, Universitat de Barcelona, Avinguda Diagonal 643, 08028, Barcelona, Spain; Institute of Research in Biodiversity (IRBio), Universitat de Barcelona, Avinguda Diagonal 643, 08028, Spain
| | - Sergi Munné-Bosch
- Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, Universitat de Barcelona, Avinguda Diagonal 643, 08028, Barcelona, Spain; Institute of Research in Biodiversity (IRBio), Universitat de Barcelona, Avinguda Diagonal 643, 08028, Spain.
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6
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Kozuleva MA, Ivanov BN. Superoxide Anion Radical Generation in Photosynthetic Electron Transport Chain. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1045-1060. [PMID: 37758306 DOI: 10.1134/s0006297923080011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/16/2023] [Accepted: 06/18/2023] [Indexed: 10/03/2023]
Abstract
This review analyzes data available in the literature on the rates, characteristics, and mechanisms of oxygen reduction to a superoxide anion radical at the sites of photosynthetic electron transport chain where this reduction has been established. The existing assumptions about the role of the components of these sites in this process are critically examined using thermodynamic approaches and results of the recent studies. The process of O2 reduction at the acceptor side of PSI, which is considered the main site of this process taking place in the photosynthetic chain, is described in detail. Evolution of photosynthetic apparatus in the context of controlling the leakage of electrons to O2 is explored. The reasons limiting application of the results obtained with the isolated segments of the photosynthetic chain to estimate the rates of O2 reduction at the corresponding sites in the intact thylakoid membrane are discussed.
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Affiliation(s)
- Marina A Kozuleva
- Institute of Basic Biological Problems, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| | - Boris N Ivanov
- Institute of Basic Biological Problems, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
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7
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Mesa T, Munné-Bosch S. α-Tocopherol in chloroplasts: Nothing more than an antioxidant? CURRENT OPINION IN PLANT BIOLOGY 2023; 74:102400. [PMID: 37311290 DOI: 10.1016/j.pbi.2023.102400] [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: 03/31/2023] [Revised: 05/10/2023] [Accepted: 05/15/2023] [Indexed: 06/15/2023]
Abstract
Among the eight forms of vitamin E, only tocopherols are essential compounds that are distributed throughout the entire plant kingdom, with α-tocopherol being the most predominant form in photosynthetic tissues. At the cellular level, α-tocopherol is of special relevance inside the chloroplast, where it eliminates singlet oxygen and modulates lipid peroxidation. This is of utmost relevance since tocopherols are the only antioxidants that counteract lipid peroxidation. Moreover, at the whole-plant level, α-tocopherol appears to modulate several physiological processes from germination to senescence. The antioxidant role of α-tocopherol at the cellular level can have profound effects at the whole-plant level, including the modulation of physiological processes that are apparently not related to redox processes and could be considered non-antioxidant functions. Here, we discuss whether non-antioxidant functions of α-tocopherol at the whole-plant level are mediated by its antioxidant role in chloroplasts and the regulation of redox processes at the cellular level.
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Affiliation(s)
- Tania Mesa
- Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Faculty of Biology, Av. Diagonal 643, E-08028, Barcelona, Spain
| | - Sergi Munné-Bosch
- Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Faculty of Biology, Av. Diagonal 643, E-08028, Barcelona, Spain; Research Institute of Nutrition and Food Safety, University of Barcelona, Faculty of Biology, Av. Diagonal 643, E-08028, Barcelona, Spain.
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8
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Calderon RH, de Vitry C, Wollman FA, Niyogi KK. Rubredoxin 1 promotes the proper folding of D1 and is not required for heme b 559 assembly in Chlamydomonas photosystem II. J Biol Chem 2023; 299:102968. [PMID: 36736898 PMCID: PMC9986647 DOI: 10.1016/j.jbc.2023.102968] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 02/04/2023] Open
Abstract
Photosystem II (PSII), the water:plastoquinone oxidoreductase of oxygenic photosynthesis, contains a heme b559 iron whose axial ligands are provided by histidine residues from the α (PsbE) and β (PsbF) subunits. PSII assembly depends on accessory proteins that facilitate the step-wise association of its protein and pigment components into a functional complex, a process that is challenging to study due to the low accumulation of assembly intermediates. Here, we examined the putative role of the iron[1Fe-0S]-containing protein rubredoxin 1 (RBD1) as an assembly factor for cytochrome b559, using the RBD1-lacking 2pac mutant from Chlamydomonas reinhardtii, in which the accumulation of PSII was rescued by the inactivation of the thylakoid membrane FtsH protease. To this end, we constructed the double mutant 2pac ftsh1-1, which harbored PSII dimers that sustained its photoautotrophic growth. We purified PSII from the 2pac ftsh1-1 background and found that α and β cytochrome b559 subunits are still present and coordinate heme b559 as in the WT. Interestingly, immunoblot analysis of dark- and low light-grown 2pac ftsh1-1 showed the accumulation of a 23-kDa fragment of the D1 protein, a marker typically associated with structural changes resulting from photodamage of PSII. Its cleavage occurs in the vicinity of a nonheme iron which binds to PSII on its electron acceptor side. Altogether, our findings demonstrate that RBD1 is not required for heme b559 assembly and point to a role for RBD1 in promoting the proper folding of D1, possibly via delivery or reduction of the nonheme iron during PSII assembly.
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Affiliation(s)
- Robert H Calderon
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA; Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden.
| | - Catherine de Vitry
- Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 7141, Centre National de la Recherche Scientifique and Sorbonne Université, Institut de Biologie Physico-Chimique, Paris, France
| | - Francis-André Wollman
- Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 7141, Centre National de la Recherche Scientifique and Sorbonne Université, Institut de Biologie Physico-Chimique, Paris, France
| | - Krishna K Niyogi
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA; Howard Hughes Medical Institute, University of California, Berkeley, California, USA
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9
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Pandey J, Devadasu E, Saini D, Dhokne K, Marriboina S, Raghavendra AS, Subramanyam R. Reversible changes in structure and function of photosynthetic apparatus of pea (Pisum sativum) leaves under drought stress. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 113:60-74. [PMID: 36377283 DOI: 10.1111/tpj.16034] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 11/08/2022] [Indexed: 06/16/2023]
Abstract
The effects of drought on photosynthesis have been extensively studied, whereas those on thylakoid organization are limited. We observed a significant decline in gas exchange parameters of pea (Pisum sativum) leaves under progressive drought stress. Chl a fluorescence kinetics revealed the reduction of photochemical efficiency of photosystem (PS)II and PSI. The non-photochemical quenching (NPQ) and the levels of PSII subunit PSBS increased. Furthermore, the light-harvesting complexes (LHCs) and some of the PSI and PSII core proteins were disassembled in drought conditions, whereas these complexes were reassociated during recovery. By contrast, the abundance of supercomplexes of PSII-LHCII and PSII dimer were reduced, whereas LHCII monomers increased following the change in the macro-organization of thylakoids. The stacks of thylakoids were loosely arranged in drought-affected plants, which could be attributed to changes in the supercomplexes of thylakoids. Severe drought stress caused a reduction of both LHCI and LHCII and a few reaction center proteins of PSI and PSII, indicating significant disorganization of the photosynthetic machinery. After 7 days of rewatering, plants recovered well, with restored chloroplast thylakoid structure and photosynthetic efficiency. The correlation of structural changes with leaf reactive oxygen species levels indicated that these changes were associated with the production of reactive oxygen species.
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Affiliation(s)
- Jayendra Pandey
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Elsinraju Devadasu
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Deepak Saini
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Kunal Dhokne
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Sureshbabu Marriboina
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Agepati S Raghavendra
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Rajagopal Subramanyam
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
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Havaux M. Review of Lipid Biomarkers and Signals of Photooxidative Stress in Plants. Methods Mol Biol 2023; 2642:111-128. [PMID: 36944875 DOI: 10.1007/978-1-0716-3044-0_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
The degree of unsaturation of plant lipids is high, making them sensitive to oxidation. They thus constitute primary targets of reactive oxygen species and oxidative stress. Moreover, the hydroperoxides generated during lipid peroxidation decompose in a variety of secondary products which can propagate oxidative stress or trigger signaling mechanisms. Both primary and secondary products of lipid oxidation are helpful markers of oxidative stress in plants. This chapter describes a number of methods that have been developed to measure those biomarkers and signals, with special emphasis on the monitoring of photooxidative stress. Depending on their characteristics, those lipid markers provide information not only on the oxidation status of plant tissues but also on the origin of lipid peroxidation, the localization of the damage, or the type of reactive oxygen species involved.
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Affiliation(s)
- Michel Havaux
- Aix-Marseille University, CEA, CNRS, UMR7265, Bioscience and Biotechnology Institute of Aix-Marseille, CEA/Cadarache, Saint-Paul-lez-Durance, France.
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11
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Foyer CH, Hanke G. ROS production and signalling in chloroplasts: cornerstones and evolving concepts. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:642-661. [PMID: 35665548 PMCID: PMC9545066 DOI: 10.1111/tpj.15856] [Citation(s) in RCA: 68] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/27/2022] [Accepted: 06/02/2022] [Indexed: 05/05/2023]
Abstract
Reactive oxygen species (ROS) such as singlet oxygen, superoxide (O2●- ) and hydrogen peroxide (H2 O2 ) are the markers of living cells. Oxygenic photosynthesis produces ROS in abundance, which act as a readout of a functional electron transport system and metabolism. The concept that photosynthetic ROS production is a major driving force in chloroplast to nucleus retrograde signalling is embedded in the literature, as is the role of chloroplasts as environmental sensors. The different complexes and components of the photosynthetic electron transport chain (PETC) regulate O2●- production in relation to light energy availability and the redox state of the stromal Cys-based redox systems. All of the ROS generated in chloroplasts have the potential to act as signals and there are many sulphhydryl-containing proteins and peptides in chloroplasts that have the potential to act as H2 O2 sensors and function in signal transduction. While ROS may directly move out of the chloroplasts to other cellular compartments, ROS signalling pathways can only be triggered if appropriate ROS-sensing proteins are present at or near the site of ROS production. Chloroplast antioxidant systems serve either to propagate these signals or to remove excess ROS that cannot effectively be harnessed in signalling. The key challenge is to understand how regulated ROS delivery from the PETC to the Cys-based redox machinery is organised to transmit redox signals from the environment to the nucleus. Redox changes associated with stromal carbohydrate metabolism also play a key role in chloroplast signalling pathways.
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Affiliation(s)
- Christine H. Foyer
- School of Biosciences, College of Life and Environmental SciencesUniversity of BirminghamEdgbastonB15 2TTUK
| | - Guy Hanke
- School of Biological and Chemical SciencesQueen Mary University of LondonMile End RoadLondonE1 4NSUK
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Chen Z, Qiu S, Li M, Zhou D, Ge S. Instant Inhibition and Subsequent Self-Adaptation of Chlorella sp. Toward Free Ammonia Shock in Wastewater: Physiological and Genetic Responses. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:9641-9650. [PMID: 35737736 DOI: 10.1021/acs.est.1c08001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Free ammonia (FA) has been recently demonstrated as the primary stress factor suppressing microalgal activities in high-ammonium wastewater. However, its inhibition mechanism and microalgal self-adaptive regulations remain unknown. This study revealed an initial inhibition and subsequent self-adaptation of a wastewater-indigenous Chlorella sp. exposed to FA shock. Mutual physiological and transcriptome analysis indicated that genetic information processing, photosynthesis, and nutrient metabolism were the most influenced metabolic processes. Specifically, for the inhibition behavior, DNA damage was indicated by the significantly up-regulated related genes, leading to the activation of cell cycle checkpoints, programmed apoptosis, and suppressed microalgal growth; FA shock inhibited the photosynthetic activities including both light and dark reactions and photoprotection through non-photochemical quenching; ammonium uptake was also suppressed with the inhibited glutamine synthetase/glutamine α-oxoglutarate aminotransferase cycle and the inactivated glutamate dehydrogenase pathway. With respect to microalgal self-adaptation, DNA damage possibly enhanced overall cell viability through reprogramming the cell fate; recovered nutrient uptake provided substances for self-adaptation activities including amino acid biosynthesis, energy production and storage, and genetic information processing; elevated light reactions further promoted self-adaptation through photodamage repair, photoprotection, and antioxidant systems. These findings enrich our knowledge of microalgal molecular responses to FA shock, facilitating the development of engineering optimization strategies for the microalgal wastewater bioremediation system.
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Affiliation(s)
- Zhipeng Chen
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing, 210094 Jiangsu, China
| | - Shuang Qiu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing, 210094 Jiangsu, China
| | - Mengting Li
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing, 210094 Jiangsu, China
| | - Di Zhou
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing, 210094 Jiangsu, China
| | - Shijian Ge
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing, 210094 Jiangsu, China
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Kale RS, Seep JL, Sallans L, Frankel LK, Bricker TM. Oxidative modification of LHC II associated with photosystem II and PS I-LHC I-LHC II membranes. PHOTOSYNTHESIS RESEARCH 2022; 152:261-274. [PMID: 35179681 DOI: 10.1007/s11120-022-00902-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 02/01/2022] [Indexed: 05/22/2023]
Abstract
Under aerobic conditions the production of Reactive Oxygen Species (ROS) by electron transport chains is unavoidable, and occurs in both autotrophic and heterotrophic organisms. In photosynthetic organisms both Photosystem II (PS II) and Photosystem I (PS I), in addition to the cytochrome b6/f complex, are demonstrated sources of ROS. All of these membrane protein complexes exhibit oxidative damage when isolated from field-grown plant material. An additional possible source of ROS in PS I and PS II is the distal, chlorophyll-containing light-harvesting array LHC II, which is present in both photosystems. These serve as possible sources of 1O2 produced by the interaction of 3O2 with 3chl* produced by intersystem crossing. We have hypothesized that amino acid residues close to the sites of ROS generation will be more susceptible to oxidative modification than distant residues. In this study, we have identified oxidized amino acid residues in a subset of the spinach LHC II proteins (Lhcb1 and Lhcb2) that were associated with either PS II membranes (i.e. BBYs) or PS I-LHC I-LHC II membranes, both of which were isolated from field-grown spinach. We identified oxidatively modified residues by high-resolution tandem mass spectrometry. Interestingly, two different patterns of oxidative modification were evident for the Lhcb1 and Lhcb2 proteins from these different sources. In the LHC II associated with PS II membranes, oxidized residues were identified to be located on the stromal surface of Lhcb1 and, to a much lesser extent, Lhcb2. Relatively few oxidized residues were identified as buried in the hydrophobic core of these proteins. The LHC II associated with PS I-LHC I-LHC II membranes, however, exhibited fewer surface-oxidized residues but, rather a large number of oxidative modifications buried in the hydrophobic core regions of both Lhcb1 and Lhcb2, adjacent to the chlorophyll prosthetic groups. These results appear to indicate that ROS, specifically 1O2, can modify the Lhcb proteins associated with both photosystems and that the LHC II associated with PS II membranes represent a different population from the LHC II associated with PS I-LHC I-LHC II membranes.
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Affiliation(s)
- Ravindra S Kale
- Department of Biological Sciences, Biochemistry and Molecular Biology Section, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Jacob L Seep
- Department of Biological Sciences, Biochemistry and Molecular Biology Section, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Larry Sallans
- The Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, OH, 45221, USA
| | - Laurie K Frankel
- Department of Biological Sciences, Biochemistry and Molecular Biology Section, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Terry M Bricker
- Department of Biological Sciences, Biochemistry and Molecular Biology Section, Louisiana State University, Baton Rouge, LA, 70803, USA.
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14
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Pospíšil P, Kumar A, Prasad A. Reactive oxygen species in photosystem II: relevance for oxidative signaling. PHOTOSYNTHESIS RESEARCH 2022; 152:245-260. [PMID: 35644020 DOI: 10.1007/s11120-022-00922-x] [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: 12/03/2021] [Accepted: 04/30/2022] [Indexed: 06/15/2023]
Abstract
Reactive oxygen species (ROS) are formed in photosystem II (PSII) under various types of abiotic and biotic stresses. It is considered that ROS play a role in chloroplast-to-nucleus retrograde signaling, which changes the nuclear gene expression. However, as ROS lifetime and diffusion are restricted due to the high reactivity towards biomolecules (lipids, pigments, and proteins) and the spatial specificity of signal transduction is low, it is not entirely clear how ROS might transduce signal from the chloroplasts to the nucleus. Biomolecule oxidation was formerly connected solely with damage; nevertheless, the evidence appears that oxidatively modified lipids and pigments are be involved in chloroplast-to-nucleus retrograde signaling due to their long diffusion distance. Moreover, oxidatively modified proteins show high spatial specificity; however, their role in signal transduction from chloroplasts to the nucleus has not been proven yet. The review attempts to summarize and evaluate the evidence for the involvement of ROS in oxidative signaling in PSII.
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Affiliation(s)
- Pavel Pospíšil
- Department of Biophysics, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic.
| | - Aditya Kumar
- Department of Biophysics, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
| | - Ankush Prasad
- Department of Biophysics, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
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15
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Regulation of the generation of reactive oxygen species during photosynthetic electron transport. Biochem Soc Trans 2022; 50:1025-1034. [PMID: 35437580 DOI: 10.1042/bst20211246] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/31/2022] [Accepted: 04/04/2022] [Indexed: 11/17/2022]
Abstract
Light capture by chlorophylls and photosynthetic electron transport bury the risk of the generation of reactive oxygen species (ROS) including singlet oxygen, superoxide anion radicals and hydrogen peroxide. Rapid changes in light intensity, electron fluxes and accumulation of strong oxidants and reductants increase ROS production. Superoxide is mainly generated at the level of photosystem I while photosystem II is the main source of singlet oxygen. ROS can induce oxidative damage of the photosynthetic apparatus, however, ROS are also important to tune processes inside the chloroplast and participate in retrograde signalling regulating the expression of genes involved in acclimation responses. Under most physiological conditions light harvesting and photosynthetic electron transport are regulated to keep the level of ROS at a non-destructive level. Photosystem II is most prone to photoinhibition but can be quickly repaired while photosystem I is protected in most cases. The size of the transmembrane proton gradient is central for the onset of mechanisms that protect against photoinhibition. The proton gradient allows dissipation of excess energy as heat in the antenna systems and it regulates electron transport. pH-dependent slowing down of electron donation to photosystem I protects it against ROS generation and damage. Cyclic electron transfer and photoreduction of oxygen contribute to the size of the proton gradient. The yield of singlet oxygen production in photosystem II is regulated by changes in the midpoint potential of its primary quinone acceptor. In addition, numerous antioxidants inside the photosystems, the antenna and the thylakoid membrane quench or scavenge ROS.
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16
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Multi-Fold Enhancement of Tocopherol Yields Employing High CO2 Supplementation and Nitrate Limitation in Native Isolate Monoraphidium sp. Cells 2022; 11:cells11081315. [PMID: 35455994 PMCID: PMC9032582 DOI: 10.3390/cells11081315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/25/2022] [Accepted: 03/25/2022] [Indexed: 02/04/2023] Open
Abstract
Tocopherols are the highly active form of the antioxidant molecules involved in scavenging of free radicals and protect the cell membranes from reactive oxygen species (ROS). In the present study, we focused on employing carbon supplementation with varying nitrate concentrations to enhance the total tocopherol yields in the native isolate Monoraphidium sp. CABeR41. The total tocopherol productivity of NRHC (Nitrate replete + 3% CO2) supplemented was (306.14 µg·L−1 d−1) which was nearly 2.5-fold higher compared to NRVLC (Nitrate replete + 0.03% CO2) (60.35 µg·L−1 d−1). The best tocopherol productivities were obtained in the NLHC (Nitrate limited + 3% CO2) supplemented cells (734.38 µg·L−1 d−1) accompanied by a significant increase in cell biomass (2.65-fold) and total lipids (6.25-fold). Further, global metabolomics using gas chromatography-mass spectrometry (GC-MS) was done in the defined conditions to elucidate the molecular mechanism during tocopherol accumulation. In the present study, the Monoraphidium sp. responded to nitrogen limitation by increase in nitrogen assimilation, with significant upregulation in gamma-Aminobutyric acid (GABA). Moreover, the tricarboxylic acid (TCA) cycle upregulation depicted increased availability of carbon skeletons and reducing power, which is leading to increased biomass yields along with the other biocommodities. In conclusion, our study depicts valorization of carbon dioxide as a cost-effective alternative for the enhancement of biomass along with tocopherols and other concomitant products like lipids and carotenoids in the indigenous strain Monoraphidium sp., as an industrial potential strain with relevance in nutraceuticals and pharmaceuticals.
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17
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Zulfiqar F, Ashraf M. Antioxidants as modulators of arsenic-induced oxidative stress tolerance in plants: An overview. JOURNAL OF HAZARDOUS MATERIALS 2022; 427:127891. [PMID: 34848065 DOI: 10.1016/j.jhazmat.2021.127891] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 11/14/2021] [Accepted: 11/21/2021] [Indexed: 05/24/2023]
Abstract
Arsenic (As) is a highly toxic contaminant in the environment. Although both inorganic and organic types of arsenic exist in the environment, the most common inorganic forms of As that adversely affect plants are arsenite (As III) and arsenate (As V). Despite no evidence for As being essential for plant growth, exposure of roots to this element can cause its uptake primarily via transporters responsible for the transport of essential mineral nutrients. Arsenic exposure even at low concentrations disturbs the plant normal functioning via excessive generation of reactive oxygen species, a condition known as oxidative stress leading to an imbalance in the redox system of the plant. This is associated with considerable damage to the cell components thereby impairing normal cellular functions and activation of several cell survival and cell death pathways. To counteract this oxidative disorder, plants possess natural defense mechanisms such as chemical species and enzymatic antioxidants. This review considers how different types of antioxidants participate in the oxidative defense mechanism to alleviate As stress in plants. Since the underlying phenomena of oxidative stress tolerance are not yet fully elucidated, the potential for "Omics" technologies to uncover molecular mechanisms are discussed. Various strategies to improve As-induced oxidative tolerance in plants such as exogenous supplementation of effective growth regulators, protectant chemicals, transgenic approaches, and genome editing are also discussed thoroughly in this review.
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Affiliation(s)
- Faisal Zulfiqar
- Department of Horticultural Sciences, Faculty of Agriculture and Environment, The Islamia University of Bahawalpur, Bahawalpur 63100, Pakistan.
| | - Muhammad Ashraf
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan
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18
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Ozaki H, Takagi D, Mizokami Y, Tokida T, Nakamura H, Sakai H, Hasegawa T, Noguchi K. Low N level increases the susceptibility of PSI to photoinhibition induced by short repetitive flashes in leaves of different rice varieties. PHYSIOLOGIA PLANTARUM 2022; 174:e13644. [PMID: 35112363 DOI: 10.1111/ppl.13644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/28/2022] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
The recovery from photoinhibition is much slower in photosystem (PS) I than in PSII; therefore, the susceptibility of PSI to photoinhibition is important with respect to photosynthetic production under special physiological conditions. Previous studies have shown that repetitive short-pulse (rSP) illumination selectively induces PSI photoinhibition. Depending on the growth light intensity or the variety/species of the plant, PSI photoinhibition is different, but the underlying mechanisms remain unknown. Here, we aimed to clarify whether the differences in the susceptibility of PSI to photoinhibition depend on environmental factors or on rice varieties and which physiological properties of the plant are related to this susceptibility. We exposed mature leaves of rice plants to rSP illumination. We examined the effects of elevated CO2 concentration and low N during growth on the susceptibility of PSI to photoinhibition and compared it in 12 different varieties. We fitted the decrease in the quantum yield of PSI during rSP illumination and estimated a parameter indicating susceptibility. Low N level increased susceptibility, whereas elevated CO2 concentration did not. The susceptibility differed among different rice varieties, and many indica varieties showed higher susceptibility than the temperate japonica varieties. Susceptibility was negatively correlated with the total chlorophyll content and N content. However, the decrease in P m ' value, an indicator of damaged PSI, was positively correlated with chlorophyll content. This suggests that in leaves with a larger electron transport capacity, the overall PSI activity may be less susceptible to photoinhibition, but more damaged PSI may accumulate during rSP illumination.
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Affiliation(s)
- Hiroshi Ozaki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Daisuke Takagi
- Department of Biological and Environmental Science, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
- Faculty of Agriculture, Setsunan University, Osaka, Japan
| | - Yusuke Mizokami
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Takeshi Tokida
- Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization (NARO), Ibaraki, Japan
| | | | - Hidemitsu Sakai
- Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization (NARO), Ibaraki, Japan
| | - Toshihiro Hasegawa
- Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization (NARO), Ibaraki, Japan
| | - Ko Noguchi
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
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19
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Munné-Bosch S, Puig S, Fenollosa E, Casadesús A, Fernández E. Vitamin E protects from lipid peroxidation during winter stress in the seagrass Cymodocea nodosa. PLANTA 2022; 255:41. [PMID: 35038021 PMCID: PMC8763757 DOI: 10.1007/s00425-022-03825-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
Adjustments in the antenna size and α-tocopherol contents provide protection from sustained damage in leaves of a seagrass, while low vitamin E contents appear to be enough to protect rhizomes (which appear to be more cold tolerant than leaves). Despite low temperatures can adversely affect the proper growth and development of marine angiosperms, by, among other processes, increasing reactive oxygen species production and causing oxidative damage to lipid membranes, the role of vitamin E in seagrasses, such as Cymodocea nodosa has not been explored thus far. Here, we aimed to better understand the possible role of this chain-breaking (peroxyl radical-trapping) antioxidant in response to low temperatures, and most particularly in relation to the occurrence of photo-inhibition and lipid peroxidation. Low temperatures caused an important desiccation of leaves, but not of rhizomes, which were much more tolerant to cold stress than leaves. Cold stress during winter was associated with chlorophyll loss and transient photo-inhibition, as indicated by reversible reductions in the Fv/Fm ratio. Adjustments in pigment antenna size and vitamin E contents per unit of chlorophyll during winter may help protect the photosynthetic apparatus from sustained photo-inhibitory damage and lipid peroxidation events in leaves. Rhizomes also accumulated significant amounts of vitamin E, although to a much lesser extent than leaves, and kept protected from lipid peroxidation during winter, as indicated by malondialdehyde contents, a product from secondary lipid peroxidation. It is concluded that vitamin E can help protect both leaves and rhizomes from lipid peroxidation, although cold stress during winter can cause transient photo-inhibition of the photosynthetic apparatus, in C. nodosa.
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Affiliation(s)
- Sergi Munné-Bosch
- Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
- Research Institute of Biodiversity (IrBio), Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
| | - Sandra Puig
- Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - Erola Fenollosa
- Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
- Research Institute of Biodiversity (IrBio), Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - Andrea Casadesús
- Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
- Research Institute of Biodiversity (IrBio), Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - Estrella Fernández
- Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
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20
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Li M, Kim C. Chloroplast ROS and stress signaling. PLANT COMMUNICATIONS 2022; 3:100264. [PMID: 35059631 PMCID: PMC8760138 DOI: 10.1016/j.xplc.2021.100264] [Citation(s) in RCA: 78] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/25/2021] [Accepted: 11/05/2021] [Indexed: 05/23/2023]
Abstract
Chloroplasts overproduce reactive oxygen species (ROS) under unfavorable environmental conditions, and these ROS are implicated in both signaling and oxidative damage. There is mounting evidence for their roles in translating environmental fluctuations into distinct physiological responses, but their targets, signaling cascades, and mutualism and antagonism with other stress signaling cascades and within ROS signaling remain poorly understood. Great efforts made in recent years have shed new light on chloroplast ROS-directed plant stress responses, from ROS perception to plant responses, in conditional mutants of Arabidopsis thaliana or under various stress conditions. Some articles have also reported the mechanisms underlying the complexity of ROS signaling pathways, with an emphasis on spatiotemporal regulation. ROS and oxidative modification of affected target proteins appear to induce retrograde signaling pathways to maintain chloroplast protein quality control and signaling at a whole-cell level using stress hormones. This review focuses on these seemingly interconnected chloroplast-to-nucleus retrograde signaling pathways initiated by ROS and ROS-modified target molecules. We also discuss future directions in chloroplast stress research to pave the way for discovering new signaling molecules and identifying intersectional signaling components that interact in multiple chloroplast signaling pathways.
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21
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Zeng W, Mostafa S, Lu Z, Jin B. Melatonin-Mediated Abiotic Stress Tolerance in Plants. FRONTIERS IN PLANT SCIENCE 2022; 13:847175. [PMID: 35615125 PMCID: PMC9125191 DOI: 10.3389/fpls.2022.847175] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 04/19/2022] [Indexed: 05/07/2023]
Abstract
Melatonin is a multi-functional molecule that is ubiquitous in all living organisms. Melatonin performs essential roles in plant stress tolerance; its application can reduce the harmful effects of abiotic stresses. Plant melatonin biosynthesis, which usually occurs within chloroplasts, and its related metabolic pathways have been extensively characterized. Melatonin regulates plant stress responses by directly inhibiting the accumulation of reactive oxygen and nitrogen species, and by indirectly affecting stress response pathways. In this review, we summarize recent research concerning melatonin biosynthesis, metabolism, and antioxidation; we focus on melatonin-mediated tolerance to abiotic stresses including drought, waterlogging, salt, heat, cold, heavy metal toxicity, light and others. We also examine exogenous melatonin treatment in plants under abiotic stress. Finally, we discuss future perspectives in melatonin research and its applications in plants.
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Affiliation(s)
- Wen Zeng
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Salma Mostafa
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
- Department of Floriculture, Faculty of Agriculture, Alexandria University, Alexandria, Egypt
| | - Zhaogeng Lu
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
- *Correspondence: Zhaogeng Lu,
| | - Biao Jin
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
- Biao Jin,
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22
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Photosynthetic Linear Electron Flow Drives CO 2 Assimilation in Maize Leaves. Int J Mol Sci 2021; 22:ijms22094894. [PMID: 34063101 PMCID: PMC8124781 DOI: 10.3390/ijms22094894] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 05/02/2021] [Accepted: 05/04/2021] [Indexed: 12/24/2022] Open
Abstract
Photosynthetic organisms commonly develop the strategy to keep the reaction center chlorophyll of photosystem I, P700, oxidized for preventing the generation of reactive oxygen species in excess light conditions. In photosynthesis of C4 plants, CO2 concentration is kept at higher levels around ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) by the cooperation of the mesophyll and bundle sheath cells, which enables them to assimilate CO2 at higher rates to survive under drought stress. However, the regulatory mechanism of photosynthetic electron transport for P700 oxidation is still poorly understood in C4 plants. Here, we assessed gas exchange, chlorophyll fluorescence, electrochromic shift, and near infrared absorbance in intact leaves of maize (a NADP-malic enzyme C4 subtype species) in comparison with mustard, a C3 plant. Instead of the alternative electron sink due to photorespiration in the C3 plant, photosynthetic linear electron flow was strongly suppressed between photosystems I and II, dependent on the difference of proton concentration across the thylakoid membrane (ΔpH) in response to the suppression of CO2 assimilation in maize. Linear relationships among CO2 assimilation rate, linear electron flow, P700 oxidation, ΔpH, and the oxidation rate of ferredoxin suggested that the increase of ΔpH for P700 oxidation was caused by the regulation of proton conductance of chloroplast ATP synthase but not by promoting cyclic electron flow. At the scale of intact leaves, the ratio of PSI to PSII was estimated almost 1:1 in both C3 and C4 plants. Overall, the photosynthetic electron transport was regulated for P700 oxidation in maize through the same strategies as in C3 plants only except for the capacity of photorespiration despite the structural and metabolic differences in photosynthesis between C3 and C4 plants.
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