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Rey P, Henri P, Alric J, Blanchard L, Viola S. Participation of the stress-responsive CDSP32 thioredoxin in the modulation of chloroplast ATP-synthase activity in Solanum tuberosum. PLANT, CELL & ENVIRONMENT 2024. [PMID: 39189948 DOI: 10.1111/pce.15101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Revised: 08/06/2024] [Accepted: 08/09/2024] [Indexed: 08/28/2024]
Abstract
Plant thioredoxins (TRXs) are involved in numerous metabolic and signalling pathways, such as light-dependent regulation of photosynthesis. The atypical TRX CDSP32, chloroplastic drought-induced stress protein of 32 kDa, includes two TRX-fold domains and participates in responses to oxidative stress as an electron donor to other thiol reductases. Here, we further characterised potato lines modified for CDSP32 expression to clarify the physiological roles of the TRX. Upon high salt treatments, modified lines displayed changes in the abundance and redox status of CDSP32 antioxidant partners, and exhibited sensitivity to combined saline-alkaline stress. In non-stressed plants overexpressing CDSP32, a lower abundance of photosystem II subunits and ATP-synthase γ subunit was noticed. The CDSP32 co-suppressed line showed altered chlorophyll a fluorescence induction and impaired regulation of the transthylakoid membrane potential during dark/light and light/dark transitions. These data, in agreement with the previously reported interaction between CDSP32 and ATP-synthase γ subunit, suggest that CDSP32 affects the redox regulation of ATP-synthase activity. Consistently, modelling of protein complex 3-D structure indicates that CDSP32 could constitute a suitable partner of ATP-synthase γ subunit. We discuss the roles of the TRX in the regulation of both photosynthetic activity and enzymatic antioxidant network in relation with environmental conditions.
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Affiliation(s)
- Pascal Rey
- Aix Marseille University, CEA, CNRS, BIAM, Photosynthesis & Environment (P&E) Team, Saint Paul, France
| | - Patricia Henri
- Aix Marseille University, CEA, CNRS, BIAM, Photosynthesis & Environment (P&E) Team, Saint Paul, France
| | - Jean Alric
- Aix Marseille University, CEA, CNRS, BIAM, Photosynthesis & Environment (P&E) Team, Saint Paul, France
| | - Laurence Blanchard
- Aix Marseille University, CEA, CNRS, BIAM, Molecular and Environmental Microbiology (MEM) Team, Saint Paul, France
| | - Stefania Viola
- Aix Marseille University, CEA, CNRS, BIAM, Photosynthesis & Environment (P&E) Team, Saint Paul, France
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Chen Q, Xiao Y, Wu Z, Ming Y, Xiao W, Wang HB, Jin HL. m-Type thioredoxin regulates cytochrome b6f complex of photosynthesis. PLANT PHYSIOLOGY 2024; 194:1294-1298. [PMID: 38051963 DOI: 10.1093/plphys/kiad646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 11/09/2023] [Accepted: 11/09/2023] [Indexed: 12/07/2023]
Abstract
Depleting m-type thioredoxin disrupts plant cell redox, impacting cytochrome b6f in photosynthesis, hindering photosynthesis, and stunting growth.
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Affiliation(s)
- Qi Chen
- Institute of Medical Plant Physiology and Ecology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
- College of Biology and Food Engineering, Guangdong University of Education, Guangzhou 510225, China
| | - Yixian Xiao
- Institute of Medical Plant Physiology and Ecology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Zeyi Wu
- Institute of Medical Plant Physiology and Ecology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Yu Ming
- Institute of Medical Plant Physiology and Ecology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Wang Xiao
- College of Biology and Food Engineering, Guangdong University of Education, Guangzhou 510225, China
| | - Hong-Bin Wang
- Institute of Medical Plant Physiology and Ecology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Guangzhou University of Chinese Medicine), Ministry of Education, Guangzhou 510006, China
| | - Hong-Lei Jin
- Institute of Medical Plant Physiology and Ecology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
- Guangzhou Key Laboratory of Chinese Medicine Research on Prevention and Treatment of Osteoporosis, The Third Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou 510375, China
- State Key Laboratory of Traditional Chinese Medicine Syndrome, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
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Adams WW, Stewart JJ, Polutchko SK, Cohu CM, Muller O, Demmig-Adams B. Foliar Phenotypic Plasticity Reflects Adaptation to Environmental Variability. PLANTS (BASEL, SWITZERLAND) 2023; 12:2041. [PMID: 37653958 PMCID: PMC10224448 DOI: 10.3390/plants12102041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/10/2023] [Accepted: 05/18/2023] [Indexed: 09/02/2023]
Abstract
Arabidopsis thaliana ecotypes adapted to native habitats with different daylengths, temperatures, and precipitation were grown experimentally under seven combinations of light intensity and leaf temperature to assess their acclimatory phenotypic plasticity in foliar structure and function. There were no differences among ecotypes when plants developed under moderate conditions of 400 µmol photons m-2 s-1 and 25 °C. However, in response to more extreme light or temperature regimes, ecotypes that evolved in habitats with pronounced differences in either the magnitude of changes in daylength or temperature or in precipitation level exhibited pronounced adjustments in photosynthesis and transpiration, as well as anatomical traits supporting these functions. Specifically, when grown under extremes of light intensity (100 versus 1000 µmol photons m-2 s-1) or temperature (8 °C versus 35 °C), ecotypes from sites with the greatest range of daylengths and temperature over the growing season exhibited the greatest differences in functional and structural features related to photosynthesis (light- and CO2-saturated capacity of oxygen evolution, leaf dry mass per area or thickness, phloem cells per minor vein, and water-use efficiency of CO2 uptake). On the other hand, the ecotype from the habitat with the lowest precipitation showed the greatest plasticity in features related to water transport and loss (vein density, ratio of water to sugar conduits in foliar minor veins, and transpiration rate). Despite these differences, common structure-function relationships existed across all ecotypes and growth conditions, with significant positive, linear correlations (i) between photosynthetic capacity (ranging from 10 to 110 µmol O2 m-2 s-1) and leaf dry mass per area (from 10 to 75 g m-2), leaf thickness (from 170 to 500 µm), and carbohydrate-export infrastructure (from 6 to 14 sieve elements per minor vein, from 2.5 to 8 µm2 cross-sectional area per sieve element, and from 16 to 82 µm2 cross-sectional area of sieve elements per minor vein); (ii) between transpiration rate (from 1 to 17 mmol H2O m-2 s-1) and water-transport infrastructure (from 3.5 to 8 tracheary elements per minor vein, from 13.5 to 28 µm2 cross-sectional area per tracheary element, and from 55 to 200 µm2 cross-sectional area of tracheary elements per minor vein); (iii) between the ratio of transpirational water loss to CO2 fixation (from 0.2 to 0.7 mol H2O to mmol-1 CO2) and the ratio of water to sugar conduits in minor veins (from 0.4 to 1.1 tracheary to sieve elements, from 4 to 6 µm2 cross-sectional area of tracheary to sieve elements, and from 2 to 6 µm2 cross-sectional area of tracheary elements to sieve elements per minor vein); (iv) between sugar conduits and sugar-loading cells; and (v) between water conducting and sugar conducting cells. Additionally, the proportion of water conduits to sugar conduits was greater for all ecotypes grown experimentally under warm-to-hot versus cold temperature. Thus, developmental acclimation to the growth environment included ecotype-dependent foliar structural and functional adjustments resulting in multiple common structural and functional relationships.
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Affiliation(s)
- William W. Adams
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA; (J.J.S.); (S.K.P.); (B.D.-A.)
| | - Jared J. Stewart
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA; (J.J.S.); (S.K.P.); (B.D.-A.)
| | - Stephanie K. Polutchko
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA; (J.J.S.); (S.K.P.); (B.D.-A.)
| | - Christopher M. Cohu
- Environmental Science and Technology, Colorado Mesa University, Grand Junction, CO 81502, USA;
| | - Onno Muller
- Pflanzenwissenschaften (IBG-2), Institut für Bio- und Geowissenschaften, Forschungszentrum Jülich, 52428 Jülich, Germany;
| | - Barbara Demmig-Adams
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA; (J.J.S.); (S.K.P.); (B.D.-A.)
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Delgado-Requerey V, Cejudo FJ, González MC. The Functional Relationship between NADPH Thioredoxin Reductase C, 2-Cys Peroxiredoxins, and m-Type Thioredoxins in the Regulation of Calvin-Benson Cycle and Malate-Valve Enzymes in Arabidopsis. Antioxidants (Basel) 2023; 12:antiox12051041. [PMID: 37237907 DOI: 10.3390/antiox12051041] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/28/2023] [Accepted: 04/29/2023] [Indexed: 05/28/2023] Open
Abstract
The concerted regulation of chloroplast biosynthetic pathways and NADPH extrusion via malate valve depends on f and m thioredoxins (Trxs). The finding that decreased levels of the thiol-peroxidase 2-Cys peroxiredoxin (Prx) suppress the severe phenotype of Arabidopsis mutants lacking NADPH-dependent Trx reductase C (NTRC) and Trxs f uncovered the central function of the NTRC-2-Cys-Prx redox system in chloroplast performance. These results suggest that Trxs m are also regulated by this system; however, the functional relationship between NTRC, 2-Cys Prxs, and m-type Trxs is unknown. To address this issue, we generated Arabidopsis thaliana mutants combining deficiencies in NTRC, 2-Cys Prx B, Trxs m1, and m4. The single trxm1 and trxm4 mutants showed a wild-type phenotype, growth retardation being noticed only in the trxm1m4 double mutant. Moreover, the ntrc-trxm1m4 mutant displayed a more severe phenotype than the ntrc mutant, as shown by the impaired photosynthetic performance, altered chloroplast structure, and defective light-dependent reduction in the Calvin-Benson cycle and malate-valve enzymes. These effects were suppressed by the decreased contents of 2-Cys Prx, since the quadruple ntrc-trxm1m4-2cpb mutant displayed a wild-type-like phenotype. These results show that the activity of m-type Trxs in the light-dependent regulation of biosynthetic enzymes and malate valve is controlled by the NTRC-2-Cys-Prx system.
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Affiliation(s)
- Víctor Delgado-Requerey
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas, Avenida Américo Vespucio 49, 41092 Sevilla, Spain
| | - Francisco Javier Cejudo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas, Avenida Américo Vespucio 49, 41092 Sevilla, Spain
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, 41012 Sevilla, Spain
| | - María-Cruz González
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas, Avenida Américo Vespucio 49, 41092 Sevilla, Spain
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, 41012 Sevilla, Spain
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Zhou J, Song T, Zhou H, Zhang M, Li N, Xiang J, Zhang X. Genome-wide identification, characterization, evolution, and expression pattern analyses of the typical thioredoxin gene family in wheat ( Triticum aestivum L.). FRONTIERS IN PLANT SCIENCE 2022; 13:1020584. [PMID: 36618641 PMCID: PMC9813791 DOI: 10.3389/fpls.2022.1020584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
Typical thioredoxin (TRX) plays an important role in maintaining redox balance in plants. However, the typical TRX genes in wheat still need to be comprehensively and deeply studied. In this research, a total of 48 typical TaTRX genes belonging to eight subtypes were identified via a genome-wide search in wheat, and the gene structures, protein conserved motifs, and protein 3D structures of the same subtype were very similar. Evolutionary analysis showed that there are two pairs of tandem duplication genes and 14 clusters of segmental duplication genes in typical TaTRX family members; TaTRX15, TaTRX36, and TaTRX42 had positive selection compared with the orthologs of their ancestral species; rice and maize have 11 and 13 orthologous typical TRXs with wheat, respectively. Gene Ontology (GO) analysis indicated that typical TaTRXs were involved in maintaining redox homeostasis in wheat cells. Estimation of ROS content, determination of antioxidant enzyme activity, and gene expression analysis in a line overexpressing one typical TaTRX confirmed that TRX plays an important role in maintaining redox balance in wheat. A predictive analysis of cis-acting elements in the promoter region showed that typical TaTRXs were extensively involved in various hormone metabolism and response processes to stress. The results predicted using public databases or verified using RT-qPCR show that typical TaTRXs were able to respond to biotic and abiotic stresses, and their expression in wheat was spatiotemporal. A total of 16 wheat proteins belonging to four different families interacting with typical TaTRXs were predicted. The above comprehensive analysis of typical TaTRX genes can enrich our understanding of this gene family in wheat and provide valuable insights for further gene function research.
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Affiliation(s)
- Jianfei Zhou
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China
| | - Tianqi Song
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China
| | - Hongwei Zhou
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China
| | - Mingfei Zhang
- Academy of Agricultural Sciences/Key Laboratory of Agro-Ecological Protection & Exploitation and Utilization of Animal and Plant Resources, ChiFeng University, Chifeng, Inner Mongolia, China
| | - Nan Li
- Academy of Agricultural Sciences/Key Laboratory of Agro-Ecological Protection & Exploitation and Utilization of Animal and Plant Resources, ChiFeng University, Chifeng, Inner Mongolia, China
| | - Jishan Xiang
- Academy of Agricultural Sciences/Key Laboratory of Agro-Ecological Protection & Exploitation and Utilization of Animal and Plant Resources, ChiFeng University, Chifeng, Inner Mongolia, China
| | - Xiaoke Zhang
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China
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Chen Q, Xiao Y, Ming Y, Peng R, Hu J, Wang HB, Jin HL. Quantitative proteomics reveals redox-based functional regulation of photosynthesis under fluctuating light in plants. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:2168-2186. [PMID: 35980302 DOI: 10.1111/jipb.13348] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Photosynthesis involves a series of redox reactions and is the major source of reactive oxygen species in plant cells. Fluctuating light (FL) levels, which occur commonly in natural environments, affect photosynthesis; however, little is known about the specific effects of FL on the redox regulation of photosynthesis. Here, we performed global quantitative mapping of the Arabidopsis thaliana cysteine thiol redox proteome under constant light and FL conditions. We identified 8857 redox-switched thiols in 4350 proteins, and 1501 proteins that are differentially modified depending on light conditions. Notably, proteins related to photosynthesis, especially photosystem I (PSI), are operational thiol-switching hotspots. Exposure of wild-type A. thaliana to FL resulted in decreased PSI abundance, stability, and activity. Interestingly, in response to PSI photodamage, more of the PSI assembly factor PSA3 dynamically switches to the reduced state. Furthermore, the Cys199 and Cys200 sites in PSA3 are necessary for its full function. Moreover, thioredoxin m (Trx m) proteins play roles in redox switching of PSA3, and are required for PSI activity and photosynthesis. This study thus reveals a mechanism for redox-based regulation of PSI under FL, and provides insight into the dynamic acclimation of photosynthesis in a changing environment.
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Affiliation(s)
- Qi Chen
- Institute of Medical Plant Physiology and Ecology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Yixian Xiao
- Institute of Medical Plant Physiology and Ecology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Yu Ming
- Institute of Medical Plant Physiology and Ecology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Rong Peng
- Institute of Medical Plant Physiology and Ecology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Jiliang Hu
- Institute of Medical Plant Physiology and Ecology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Hong-Bin Wang
- Institute of Medical Plant Physiology and Ecology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Hong-Lei Jin
- Institute of Medical Plant Physiology and Ecology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
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Sahrawy M, Fernández-Trijueque J, Vargas P, Serrato AJ. Comprehensive Expression Analyses of Plastidial Thioredoxins of Arabidopsis thaliana Indicate a Main Role of Thioredoxin m2 in Roots. Antioxidants (Basel) 2022; 11:antiox11071365. [PMID: 35883856 PMCID: PMC9311637 DOI: 10.3390/antiox11071365] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 11/16/2022] Open
Abstract
Thioredoxins (TRXs) f and m are redox proteins that regulate key chloroplast processes. The existence of several isoforms of TRXs f and m indicates that these redox players have followed a specialization process throughout evolution. Current research efforts are focused on discerning the signalling role of the different TRX types and their isoforms in chloroplasts. Nonetheless, little is known about their function in non-photosynthetic plastids. For this purpose, we have carried out comprehensive expression analyses by using Arabidopsis thaliana TRXf (f1 and f2) and TRXm (m1, m2, m3 and m4) genes translationally fused to the green fluorescence protein (GFP). These analyses showed that TRX m has different localisation patterns inside chloroplasts, together with a putative dual subcellular localisation of TRX f1. Apart from mesophyll cells, these TRXs were also observed in reproductive organs, stomatal guard cells and roots. We also investigated whether photosynthesis, stomatal density and aperture or root structure were affected in the TRXs f and m loss-of-function Arabidopsis mutants. Remarkably, we immunodetected TRX m2 and the Calvin−Benson cycle fructose-1,6-bisphosphatase (cFBP1) in roots. After carrying out in vitro redox activation assays of cFBP1 by plastid TRXs, we propose that cFBP1 might be activated by TRX m2 in root plastids.
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Light Intensity- and Spectrum-Dependent Redox Regulation of Plant Metabolism. Antioxidants (Basel) 2022; 11:antiox11071311. [PMID: 35883801 PMCID: PMC9312225 DOI: 10.3390/antiox11071311] [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: 05/20/2022] [Revised: 06/24/2022] [Accepted: 06/27/2022] [Indexed: 11/29/2022] Open
Abstract
Both light intensity and spectrum (280–800 nm) affect photosynthesis and, consequently, the formation of reactive oxygen species (ROS) during photosynthetic electron transport. ROS, together with antioxidants, determine the redox environment in tissues and cells, which in turn has a major role in the adjustment of metabolism to changes in environmental conditions. This process is very important since there are great spatial (latitude, altitude) and temporal (daily, seasonal) changes in light conditions which are accompanied by fluctuations in temperature, water supply, and biotic stresses. The blue and red spectral regimens are decisive in the regulation of metabolism because of the absorption maximums of chlorophylls and the sensitivity of photoreceptors. Based on recent publications, photoreceptor-controlled transcription factors such as ELONGATED HYPOCOTYL5 (HY5) and changes in the cellular redox environment may have a major role in the coordinated fine-tuning of metabolic processes during changes in light conditions. This review gives an overview of the current knowledge of the light-associated redox control of basic metabolic pathways (carbon, nitrogen, amino acid, sulphur, lipid, and nucleic acid metabolism), secondary metabolism (terpenoids, flavonoids, and alkaloids), and related molecular mechanisms. Light condition-related reprogramming of metabolism is the basis for proper growth and development of plants; therefore, its better understanding can contribute to more efficient crop production in the future.
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Shi Y, Ke X, Yang X, Liu Y, Hou X. Plants response to light stress. J Genet Genomics 2022; 49:735-747. [DOI: 10.1016/j.jgg.2022.04.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/13/2022] [Accepted: 04/26/2022] [Indexed: 11/30/2022]
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Current Knowledge on Mechanisms Preventing Photosynthesis Redox Imbalance in Plants. Antioxidants (Basel) 2021; 10:antiox10111789. [PMID: 34829660 PMCID: PMC8614926 DOI: 10.3390/antiox10111789] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 10/28/2021] [Accepted: 11/05/2021] [Indexed: 12/03/2022] Open
Abstract
Photosynthesis includes a set of redox reactions that are the source of reducing power and energy for the assimilation of inorganic carbon, nitrogen and sulphur, thus generating organic compounds, and oxygen, which supports life on Earth. As sessile organisms, plants have to face continuous changes in environmental conditions and need to adjust the photosynthetic electron transport to prevent the accumulation of damaging oxygen by-products. The balance between photosynthetic cyclic and linear electron flows allows for the maintenance of a proper NADPH/ATP ratio that is adapted to the plant’s needs. In addition, different mechanisms to dissipate excess energy operate in plants to protect and optimise photosynthesis under adverse conditions. Recent reports show an important role of redox-based dithiol–disulphide interchanges, mediated both by classical and atypical chloroplast thioredoxins (TRXs), in the control of these photoprotective mechanisms. Moreover, membrane-anchored TRX-like proteins, such as HCF164, which transfer electrons from stromal TRXs to the thylakoid lumen, play a key role in the regulation of lumenal targets depending on the stromal redox poise. Interestingly, not all photoprotective players were reported to be under the control of TRXs. In this review, we discuss recent findings regarding the mechanisms that allow an appropriate electron flux to avoid the detrimental consequences of photosynthesis redox imbalances.
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