101
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Zhu X, Pan T, Zhang X, Fan L, Quintero FJ, Zhao H, Su X, Li X, Villalta I, Mendoza I, Shen J, Jiang L, Pardo JM, Qiu QS. K + Efflux Antiporters 4, 5, and 6 Mediate pH and K + Homeostasis in Endomembrane Compartments. PLANT PHYSIOLOGY 2018; 178:1657-1678. [PMID: 30309966 PMCID: PMC6288736 DOI: 10.1104/pp.18.01053] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 10/01/2018] [Indexed: 05/20/2023]
Abstract
KEA4, KEA5, and KEA6 are members of the Arabidopsis (Arabidopsis thaliana) K+ efflux antiporter (KEA) family that share high sequence similarity but whose function remains unknown. Here, we show their gene expression pattern, subcellular localization, and physiological function in Arabidopsis. KEA4, KEA5, and KEA6 had similar tissue expression patterns, and the three KEA proteins localized to the Golgi, the trans-Golgi network, and the prevacuolar compartment/multivesicular bodies, suggesting overlapping roles of these proteins in the endomembrane system. Phenotypic analyses of single, double, and triple mutants confirmed functional redundancy. The triple mutant kea4 kea5 kea6 had small rosettes, short seedlings, and was sensitive to low K+ availability and to the sodicity imposed by high salinity. Also, the kea4 kea5 kea6 mutant plants had a reduced luminal pH in the Golgi, trans-Golgi network, prevacuolar compartment, and vacuole, in accordance with the K/H exchange activity of KEA proteins. Genetic analysis indicated that KEA4, KEA5, and KEA6 as well as endosomal Na+/H+exchanger5 (NHX5) and NHX6 acted coordinately to facilitate endosomal pH homeostasis and salt tolerance. Neither cancelling nor overexpressing the vacuolar antiporters NHX1 and NHX2 in the kea4 kea5 kea6 mutant background altered the salt-sensitive phenotype. The NHX1 and NHX2 proteins in the kea4 kea5 kea6 mutant background could not suppress the acidity of the endomembrane system but brought the vacuolar pH close to wild-type values. Together, these data signify that KEA4, KEA5, and KEA6 are endosomal K+ transporters functioning in maintaining pH and ion homeostasis in the endomembrane network.
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Affiliation(s)
- Xiaojie Zhu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China 730000
| | - Ting Pan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China 730000
| | - Xiao Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China 730000
| | - Ligang Fan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China 730000
| | - Francisco J Quintero
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Cientificas, 41092 Seville, Spain
| | - Hong Zhao
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China 730000
| | - Xiaomeng Su
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China 730000
| | - Xiaojiao Li
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China 730000
| | - Irene Villalta
- Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas, 41092 Seville, Spain
| | - Imelda Mendoza
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Cientificas, 41092 Seville, Spain
| | - Jinbo Shen
- School of Life Sciences, Center for Cell and Developmental Biology, and State Key Laboratory of Agrobiotechnology, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Liwen Jiang
- School of Life Sciences, Center for Cell and Developmental Biology, and State Key Laboratory of Agrobiotechnology, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Jose M Pardo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Cientificas, 41092 Seville, Spain
| | - Quan-Sheng Qiu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China 730000
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102
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Shimakawa G, Miyake C. Oxidation of P700 Ensures Robust Photosynthesis. FRONTIERS IN PLANT SCIENCE 2018; 9:1617. [PMID: 30459798 PMCID: PMC6232666 DOI: 10.3389/fpls.2018.01617] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/18/2018] [Indexed: 05/18/2023]
Abstract
In the light, photosynthetic cells can potentially suffer from oxidative damage derived from reactive oxygen species. Nevertheless, a variety of oxygenic photoautotrophs, including cyanobacteria, algae, and plants, manage their photosynthetic systems successfully. In the present article, we review previous research on how these photoautotrophs safely utilize light energy for photosynthesis without photo-oxidative damage to photosystem I (PSI). The reaction center chlorophyll of PSI, P700, is kept in an oxidized state in response to excess light, under high light and low CO2 conditions, to tune the light utilization and dissipate the excess photo-excitation energy in PSI. Oxidation of P700 is co-operatively regulated by a number of molecular mechanisms on both the electron donor and acceptor sides of PSI. The strategies to keep P700 oxidized are diverse among a variety of photoautotrophs, which are evolutionarily optimized for their ecological niche.
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Affiliation(s)
- Ginga Shimakawa
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Chikahiro Miyake
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, Tokyo, Japan
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103
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Nikkanen L, Toivola J, Trotta A, Diaz MG, Tikkanen M, Aro E, Rintamäki E. Regulation of cyclic electron flow by chloroplast NADPH-dependent thioredoxin system. PLANT DIRECT 2018; 2:e00093. [PMID: 31245694 PMCID: PMC6508795 DOI: 10.1002/pld3.93] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 09/12/2018] [Accepted: 10/15/2018] [Indexed: 05/18/2023]
Abstract
Linear electron transport in the thylakoid membrane drives photosynthetic NADPH and ATP production, while cyclic electron flow (CEF) around photosystem I only promotes the translocation of protons from stroma to thylakoid lumen. The chloroplast NADH dehydrogenase-like complex (NDH) participates in one CEF route transferring electrons from ferredoxin back to the plastoquinone pool with concomitant proton pumping to the lumen. CEF has been proposed to balance the ratio of ATP/NADPH production and to control the redox poise particularly in fluctuating light conditions, but the mechanisms regulating the NDH complex remain unknown. We have investigated potential regulation of the CEF pathways by the chloroplast NADPH-thioredoxin reductase (NTRC) in vivo by using an Arabidopsis knockout line of NTRC as well as lines overexpressing NTRC. Here, we present biochemical and biophysical evidence showing that NTRC stimulates the activity of NDH-dependent CEF and is involved in the regulation of generation of proton motive force, thylakoid conductivity to protons, and redox balance between the thylakoid electron transfer chain and the stroma during changes in light conditions. Furthermore, protein-protein interaction assays suggest a putative thioredoxin-target site in close proximity to the ferredoxin-binding domain of NDH, thus providing a plausible mechanism for redox regulation of the NDH ferredoxin:plastoquinone oxidoreductase activity.
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Affiliation(s)
- Lauri Nikkanen
- Molecular Plant BiologyDepartment of BiochemistryUniversity of TurkuTurkuFinland
| | - Jouni Toivola
- Molecular Plant BiologyDepartment of BiochemistryUniversity of TurkuTurkuFinland
| | - Andrea Trotta
- Molecular Plant BiologyDepartment of BiochemistryUniversity of TurkuTurkuFinland
| | - Manuel Guinea Diaz
- Molecular Plant BiologyDepartment of BiochemistryUniversity of TurkuTurkuFinland
| | - Mikko Tikkanen
- Molecular Plant BiologyDepartment of BiochemistryUniversity of TurkuTurkuFinland
| | - Eva‐Mari Aro
- Molecular Plant BiologyDepartment of BiochemistryUniversity of TurkuTurkuFinland
| | - Eevi Rintamäki
- Molecular Plant BiologyDepartment of BiochemistryUniversity of TurkuTurkuFinland
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104
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Global spectroscopic analysis to study the regulation of the photosynthetic proton motive force: A critical reappraisal. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:676-683. [DOI: 10.1016/j.bbabio.2018.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 06/03/2018] [Accepted: 07/02/2018] [Indexed: 01/11/2023]
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105
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Shimakawa G, Miyake C. Changing frequency of fluctuating light reveals the molecular mechanism for P700 oxidation in plant leaves. PLANT DIRECT 2018; 2:e00073. [PMID: 31245737 PMCID: PMC6508772 DOI: 10.1002/pld3.73] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 04/05/2018] [Accepted: 06/15/2018] [Indexed: 05/19/2023]
Abstract
Natural sunlight exceeds the demand of photosynthesis such that it can cause plants to produce reactive oxygen species (ROS), which subsequently cause photo-oxidative damage. Because photosystem I (PSI) is a major source of ROS, plants actively maintain the reaction center chlorophyll of PSI(P700) oxidized under excessive light conditions to alleviate the ROS production. P700 oxidation is universally recognized in photosynthetic organisms as a physiological response to excessive light. However, it is still poorly understood how P700 oxidation is induced in response to fluctuating light with a variety of frequencies. Here, we investigated the relationships of photosynthetic parameters with P700 oxidation in Arabidopsis thaliana under a sine fluctuating light with different frequencies. As the photon flux density of the light increased, P700 was oxidized concurrently with the chlorophyll fluorescence parameter qL unless the electron acceptor side of PSI was limited. Conversely, we did not observe a proportional relationship of non-photochemical quenching with P700 oxidation. The mutant crr-2, which lacks chloroplast NADPH dehydrogenase, was impaired in P700 oxidation during light fluctuation at high, but not low frequency, unlike the pgrl1 mutant deficient in PGR5 and PGRL1 proteins, which could not oxidize P700 during light fluctuation at both high and low frequencies. Taken together, our findings suggested that the changing frequency of fluctuating light reveals the tracking performance of molecular mechanisms underlying P700 oxidation.
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Affiliation(s)
- Ginga Shimakawa
- Department of Biological and Environmental ScienceFaculty of AgricultureGraduate School of Agricultural ScienceKobe UniversityKobeJapan
| | - Chikahiro Miyake
- Department of Biological and Environmental ScienceFaculty of AgricultureGraduate School of Agricultural ScienceKobe UniversityKobeJapan
- Core Research for Environmental Science and TechnologyJapan Science and Technology AgencyTokyoJapan
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106
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Huang W, Cai YF, Wang JH, Zhang SB. Chloroplastic ATP synthase plays an important role in the regulation of proton motive force in fluctuating light. JOURNAL OF PLANT PHYSIOLOGY 2018; 226:40-47. [PMID: 29698911 DOI: 10.1016/j.jplph.2018.03.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/25/2018] [Accepted: 03/26/2018] [Indexed: 06/08/2023]
Abstract
The proton motive force (pmf) across the thylakoid membranes plays a key role for photosynthesis in fluctuating light. However, the mechanisms underlying the regulation of pmf in fluctuating light are not well known. In this study, we aimed to identify the roles of chloroplastic ATP synthase and cyclic electron flow (CEF) around photosystem I (PSI) in the regulation of the pmf in fluctuating light. To do this, we measured chlorophyll fluorescence, P700 parameters, and the electrochromic shift signal in the fluctuating light alternating between 918 (high light) and 89 (low light) μmol photons m-2 s-1 every 5 min. We found that the activity of chloroplastic ATP synthase (gH+), pmf, CEF activity, non-photochemical quenching (NPQ), and the P700 redox state changed rapidly in fluctuating light. During transition from low to high light, the decreased gH+ and the stimulation of CEF both contributed to the rapid formation of pmf, activating NPQ and optimizing the redox state of P700 in PSI. During the low-light phases, gH+ rapidly increased and the pmf declined sharply, leading to the relaxation of NPQ and down-regulation of photosynthetic control. These findings indicate that in fluctuating light the gH+ and CEF are finely regulated to modulate the pmf formation, avoiding the over-accumulation of reactive intermediates and maximizing energy use efficiency.
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Affiliation(s)
- Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Yan-Fei Cai
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, Kunming, Yunnan, China
| | - Ji-Hua Wang
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, Kunming, Yunnan, China.
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
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107
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Marchand J, Heydarizadeh P, Schoefs B, Spetea C. Ion and metabolite transport in the chloroplast of algae: lessons from land plants. Cell Mol Life Sci 2018; 75:2153-2176. [PMID: 29541792 PMCID: PMC5948301 DOI: 10.1007/s00018-018-2793-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 03/01/2018] [Accepted: 03/07/2018] [Indexed: 12/28/2022]
Abstract
Chloroplasts are endosymbiotic organelles and play crucial roles in energy supply and metabolism of eukaryotic photosynthetic organisms (algae and land plants). They harbor channels and transporters in the envelope and thylakoid membranes, mediating the exchange of ions and metabolites with the cytosol and the chloroplast stroma and between the different chloroplast subcompartments. In secondarily evolved algae, three or four envelope membranes surround the chloroplast, making more complex the exchange of ions and metabolites. Despite the importance of transport proteins for the optimal functioning of the chloroplast in algae, and that many land plant homologues have been predicted, experimental evidence and molecular characterization are missing in most cases. Here, we provide an overview of the current knowledge about ion and metabolite transport in the chloroplast from algae. The main aspects reviewed are localization and activity of the transport proteins from algae and/or of homologues from other organisms including land plants. Most chloroplast transporters were identified in the green alga Chlamydomonas reinhardtii, reside in the envelope and participate in carbon acquisition and metabolism. Only a few identified algal transporters are located in the thylakoid membrane and play role in ion transport. The presence of genes for putative transporters in green algae, red algae, diatoms, glaucophytes and cryptophytes is discussed, and roles in the chloroplast are suggested. A deep knowledge in this field is required because algae represent a potential source of biomass and valuable metabolites for industry, medicine and agriculture.
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Affiliation(s)
- Justine Marchand
- Metabolism, Bioengineering of Microalgal Molecules and Applications (MIMMA), Mer Molécules Santé, IUML, FR 3473 CNRS, Le Mans University, 72000, Le Mans, France
| | - Parisa Heydarizadeh
- Metabolism, Bioengineering of Microalgal Molecules and Applications (MIMMA), Mer Molécules Santé, IUML, FR 3473 CNRS, Le Mans University, 72000, Le Mans, France
| | - Benoît Schoefs
- Metabolism, Bioengineering of Microalgal Molecules and Applications (MIMMA), Mer Molécules Santé, IUML, FR 3473 CNRS, Le Mans University, 72000, Le Mans, France.
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, 40530, Göteborg, Sweden.
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108
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Cardona T, Shao S, Nixon PJ. Enhancing photosynthesis in plants: the light reactions. Essays Biochem 2018; 62:85-94. [PMID: 29563222 PMCID: PMC5897789 DOI: 10.1042/ebc20170015] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 01/23/2018] [Accepted: 01/29/2018] [Indexed: 12/20/2022]
Abstract
In this review, we highlight recent research and current ideas on how to improve the efficiency of the light reactions of photosynthesis in crops. We note that the efficiency of photosynthesis is a balance between how much energy is used for growth and the energy wasted or spent protecting the photosynthetic machinery from photodamage. There are reasons to be optimistic about enhancing photosynthetic efficiency, but many appealing ideas are still on the drawing board. It is envisioned that the crops of the future will be extensively genetically modified to tailor them to specific natural or artificial environmental conditions.
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Affiliation(s)
- Tanai Cardona
- Department of Life Sciences, Sir Ernst Chain Building - Wolfson Laboratories, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K
| | - Shengxi Shao
- Department of Life Sciences, Sir Ernst Chain Building - Wolfson Laboratories, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K
| | - Peter J Nixon
- Department of Life Sciences, Sir Ernst Chain Building - Wolfson Laboratories, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K.
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109
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Davis GA, Rutherford AW, Kramer DM. Hacking the thylakoid proton motive force for improved photosynthesis: modulating ion flux rates that control proton motive force partitioning into Δ ψ and ΔpH. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0381. [PMID: 28808100 DOI: 10.1098/rstb.2016.0381] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/31/2017] [Indexed: 11/12/2022] Open
Abstract
There is considerable interest in improving plant productivity by altering the dynamic responses of photosynthesis in tune with natural conditions. This is exemplified by the 'energy-dependent' form of non-photochemical quenching (qE), the formation and decay of which can be considerably slower than natural light fluctuations, limiting photochemical yield. In addition, we recently reported that rapidly fluctuating light can produce field recombination-induced photodamage (FRIP), where large spikes in electric field across the thylakoid membrane (Δψ) induce photosystem II recombination reactions that produce damaging singlet oxygen (1O2). Both qE and FRIP are directly linked to the thylakoid proton motive force (pmf), and in particular, the slow kinetics of partitioning pmf into its ΔpH and Δψ components. Using a series of computational simulations, we explored the possibility of 'hacking' pmf partitioning as a target for improving photosynthesis. Under a range of illumination conditions, increasing the rate of counter-ion fluxes across the thylakoid membrane should lead to more rapid dissipation of Δψ and formation of ΔpH. This would result in increased rates for the formation and decay of qE while resulting in a more rapid decline in the amplitudes of Δψ-spikes and decreasing 1O2 production. These results suggest that ion fluxes may be a viable target for plant breeding or engineering. However, these changes also induce transient, but substantial mismatches in the ATP : NADPH output ratio as well as in the osmotic balance between the lumen and stroma, either of which may explain why evolution has not already accelerated thylakoid ion fluxes. Overall, though the model is simplified, it recapitulates many of the responses seen in vivo, while spotlighting critical aspects of the complex interactions between pmf components and photosynthetic processes. By making the programme available, we hope to enable the community of photosynthesis researchers to further explore and test specific hypotheses.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'.
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Affiliation(s)
- Geoffry A Davis
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA.,Cell and Molecular Biology Graduate Program, Michigan State University, East Lansing, MI 48824, USA
| | | | - David M Kramer
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA .,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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110
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Kaiser E, Matsubara S, Harbinson J, Heuvelink E, Marcelis LFM. Acclimation of photosynthesis to lightflecks in tomato leaves: interaction with progressive shading in a growing canopy. PHYSIOLOGIA PLANTARUM 2018; 162:506-517. [PMID: 29125181 DOI: 10.1111/ppl.12668] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 10/20/2017] [Accepted: 10/29/2017] [Indexed: 05/23/2023]
Abstract
Plants in natural environments are often exposed to fluctuations in light intensity, and leaf-level acclimation to light may be affected by those fluctuations. Concurrently, leaves acclimated to a given light climate can become progressively shaded as new leaves emerge and grow above them. Acclimation to shade alters characteristics such as photosynthetic capacity. To investigate the interaction of fluctuating light and progressive shading, we exposed three-week old tomato (Solanum lycopersicum) plants to either lightflecks or constant light intensities. Lightflecks of 20 s length and 1000 μmol m-2 s-1 peak intensity were applied every 5 min for 16 h per day, for 3 weeks. Lightfleck and constant light treatments received identical daily light sums (15.2 mol m-2 day-1 ). Photosynthesis was monitored in leaves 2 and 4 (counting from the bottom) during canopy development throughout the experiment. Several dynamic and steady-state characteristics of photosynthesis became enhanced by fluctuating light when leaves were partially shaded by the upper canopy, but much less so when they were fully exposed to lightflecks. This was the case for CO2 -saturated photosynthesis rates in leaves 2 and 4 growing under lightflecks 14 days into the treatment period. Also, leaf 2 of plants in the lightfleck treatment showed significantly faster rates of photosynthetic induction when exposed to a stepwise change in light intensity on day 15. As the plants grew larger and these leaves became increasingly shaded, acclimation of leaf-level photosynthesis to lightflecks disappeared. These results highlight continuous acclimation of leaf photosynthesis to changing light conditions inside developing canopies.
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Affiliation(s)
- Elias Kaiser
- Horticulture and Product Physiology, Department of Plant Sciences, Wageningen University, Wageningen, the Netherlands
| | | | - Jeremy Harbinson
- Horticulture and Product Physiology, Department of Plant Sciences, Wageningen University, Wageningen, the Netherlands
| | - Ep Heuvelink
- Horticulture and Product Physiology, Department of Plant Sciences, Wageningen University, Wageningen, the Netherlands
| | - Leo F M Marcelis
- Horticulture and Product Physiology, Department of Plant Sciences, Wageningen University, Wageningen, the Netherlands
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111
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Potassium: A Vital Regulator of Plant Responses and Tolerance to Abiotic Stresses. AGRONOMY-BASEL 2018. [DOI: 10.3390/agronomy8030031] [Citation(s) in RCA: 162] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Among the plant nutrients, potassium (K) is one of the vital elements required for plant growth and physiology. Potassium is not only a constituent of the plant structure but it also has a regulatory function in several biochemical processes related to protein synthesis, carbohydrate metabolism, and enzyme activation. Several physiological processes depend on K, such as stomatal regulation and photosynthesis. In recent decades, K was found to provide abiotic stress tolerance. Under salt stress, K helps to maintain ion homeostasis and to regulate the osmotic balance. Under drought stress conditions, K regulates stomatal opening and helps plants adapt to water deficits. Many reports support the notion that K enhances antioxidant defense in plants and therefore protects them from oxidative stress under various environmental adversities. In addition, this element provides some cellular signaling alone or in association with other signaling molecules and phytohormones. Although considerable progress has been made in understanding K-induced abiotic stress tolerance in plants, the exact molecular mechanisms of these protections are still under investigation. In this review, we summarized the recent literature on the biological functions of K, its uptake, its translocation, and its role in plant abiotic stress tolerance.
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112
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Morales A, Kaiser E, Yin X, Harbinson J, Molenaar J, Driever SM, Struik PC. Dynamic modelling of limitations on improving leaf CO 2 assimilation under fluctuating irradiance. PLANT, CELL & ENVIRONMENT 2018; 41:589-604. [PMID: 29243271 DOI: 10.1111/pce.13119] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 11/24/2017] [Accepted: 12/01/2017] [Indexed: 05/21/2023]
Abstract
A dynamic model of leaf CO2 assimilation was developed as an extension of the canonical steady-state model, by adding the effects of energy-dependent non-photochemical quenching (qE), chloroplast movement, photoinhibition, regulation of enzyme activity in the Calvin cycle, metabolite concentrations, and dynamic CO2 diffusion. The model was calibrated and tested successfully using published measurements of gas exchange and chlorophyll fluorescence on Arabidopsis thaliana ecotype Col-0 and several photosynthetic mutants and transformants affecting the regulation of Rubisco activity (rca-2 and rwt43), non-photochemical quenching (npq4-1 and npq1-2), and sucrose synthesis (spsa1). The potential improvements on CO2 assimilation under fluctuating irradiance that can be achieved by removing the kinetic limitations on the regulation of enzyme activities, electron transport, and stomatal conductance were calculated in silico for different scenarios. The model predicted that the rates of activation of enzymes in the Calvin cycle and stomatal opening were the most limiting (up to 17% improvement) and that effects varied with the frequency of fluctuations. On the other hand, relaxation of qE and chloroplast movement had a strong effect on average low-irradiance CO2 assimilation (up to 10% improvement). Strong synergies among processes were found, such that removing all kinetic limitations simultaneously resulted in improvements of up to 32%.
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Affiliation(s)
- Alejandro Morales
- Centre for Crop Systems Analysis, Wageningen University & Research, Wageningen, The Netherlands
| | - Elias Kaiser
- Horticulture and Product Physiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Xinyou Yin
- Centre for Crop Systems Analysis, Wageningen University & Research, Wageningen, The Netherlands
| | - Jeremy Harbinson
- Horticulture and Product Physiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Jaap Molenaar
- Biometris, Mathematical and Statistical Methods Group, Wageningen University & Research, Wageningen, The Netherlands
| | - Steven M Driever
- Centre for Crop Systems Analysis, Wageningen University & Research, Wageningen, The Netherlands
| | - Paul C Struik
- Centre for Crop Systems Analysis, Wageningen University & Research, Wageningen, The Netherlands
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113
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Fox H, Doron-Faigenboim A, Kelly G, Bourstein R, Attia Z, Zhou J, Moshe Y, Moshelion M, David-Schwartz R. Transcriptome analysis of Pinus halepensis under drought stress and during recovery. TREE PHYSIOLOGY 2018; 38:423-441. [PMID: 29177514 PMCID: PMC5982726 DOI: 10.1093/treephys/tpx137] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 08/24/2017] [Accepted: 10/12/2017] [Indexed: 05/09/2023]
Abstract
Forest trees use various strategies to cope with drought stress and these strategies involve complex molecular mechanisms. Pinus halepensis Miller (Aleppo pine) is found throughout the Mediterranean basin and is one of the most drought-tolerant pine species. In order to decipher the molecular mechanisms that P. halepensis uses to withstand drought, we performed large-scale physiological and transcriptome analyses. We selected a mature tree from a semi-arid area with suboptimal growth conditions for clonal propagation through cuttings. We then used a high-throughput experimental system to continuously monitor whole-plant transpiration rates, stomatal conductance and the vapor pressure deficit. The transcriptomes of plants were examined at six physiological stages: pre-stomatal response, partial stomatal closure, minimum transpiration, post-irrigation, partial recovery and full recovery. At each stage, data from plants exposed to the drought treatment were compared with data collected from well-irrigated control plants. A drought-stressed P. halepensis transcriptome was created using paired-end RNA-seq. In total, ~6000 differentially expressed, non-redundant transcripts were identified between drought-treated and control trees. Cluster analysis has revealed stress-induced down-regulation of transcripts related to photosynthesis, reactive oxygen species (ROS)-scavenging through the ascorbic acid (AsA)-glutathione cycle, fatty acid and cell wall biosynthesis, stomatal activity, and the biosynthesis of flavonoids and terpenoids. Up-regulated processes included chlorophyll degradation, ROS-scavenging through AsA-independent thiol-mediated pathways, abscisic acid response and accumulation of heat shock proteins, thaumatin and exordium. Recovery from drought induced strong transcription of retrotransposons, especially the retrovirus-related transposon Tnt1-94. The drought-related transcriptome illustrates this species' dynamic response to drought and recovery and unravels novel mechanisms.
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Affiliation(s)
- Hagar Fox
- Institute of Plant Sciences, Volcani Center, ARO, Bet Dagan 50250, Israel
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | | | - Gilor Kelly
- Institute of Plant Sciences, Volcani Center, ARO, Bet Dagan 50250, Israel
| | - Ronny Bourstein
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Ziv Attia
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Jing Zhou
- Institute of Plant Sciences, Volcani Center, ARO, Bet Dagan 50250, Israel
| | - Yosef Moshe
- Institute of Plant Sciences, Volcani Center, ARO, Bet Dagan 50250, Israel
| | - Menachem Moshelion
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
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114
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Dahal K, Vanlerberghe GC. Improved chloroplast energy balance during water deficit enhances plant growth: more crop per drop. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1183-1197. [PMID: 29281082 PMCID: PMC6018952 DOI: 10.1093/jxb/erx474] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 12/07/2017] [Indexed: 05/02/2023]
Abstract
The non-energy-conserving alternative oxidase (AOX) respiration of plant mitochondria is known to interact with chloroplast photosynthesis. This may have consequences for growth, particularly under sub-optimal conditions when energy imbalances can impede photosynthesis. This hypothesis was tested by comparing the metabolism and growth of wild-type Nicotiana tabacum with that of AOX knockdown and overexpression lines during a prolonged steady-state mild to moderate water deficit. Under moderate water deficit, the AOX amount was an important determinant of the rate of both mitochondrial respiration in the light and net photosynthetic CO2 assimilation (A) at the growth irradiance. In particular, AOX respiration was necessary to maintain optimal proton and electron fluxes at the chloroplast thylakoid membrane, which in turn prevented a water-deficit-induced biochemical limitation of photosynthesis. As a result of differences in A, AOX overexpressors gained more biomass and knockdowns gained less biomass than wild-type during moderate water deficit. Biomass partitioning also differed, with the overexpressors having a higher percentage, and the knockdowns having a lower percentage, of total above-ground biomass in reproductive tissue than wild-type. The results establish that improving chloroplast energy balance by using a non-energy-conserving respiratory electron sink can increase photosynthesis and growth during prolonged water deficit.
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Affiliation(s)
- Keshav Dahal
- Department of Biological Sciences and Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Greg C Vanlerberghe
- Department of Biological Sciences and Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, Ontario, Canada
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115
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Morales A, Yin X, Harbinson J, Driever SM, Molenaar J, Kramer DM, Struik PC. In Silico Analysis of the Regulation of the Photosynthetic Electron Transport Chain in C3 Plants. PLANT PHYSIOLOGY 2018; 176:1247-1261. [PMID: 28924017 PMCID: PMC5813522 DOI: 10.1104/pp.17.00779] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 09/13/2017] [Indexed: 05/18/2023]
Abstract
We present a new simulation model of the reactions in the photosynthetic electron transport chain of C3 species. We show that including recent insights about the regulation of the thylakoid proton motive force, ATP/NADPH balancing mechanisms (cyclic and noncyclic alternative electron transport), and regulation of Rubisco activity leads to emergent behaviors that may affect the operation and regulation of photosynthesis under different dynamic environmental conditions. The model was parameterized with experimental results in the literature, with a focus on Arabidopsis (Arabidopsis thaliana). A dataset was constructed from multiple sources, including measurements of steady-state and dynamic gas exchange, chlorophyll fluorescence, and absorbance spectroscopy under different light intensities and CO2, to test predictions of the model under different experimental conditions. Simulations suggested that there are strong interactions between cyclic and noncyclic alternative electron transport and that an excess capacity for alternative electron transport is required to ensure adequate redox state and lumen pH. Furthermore, the model predicted that, under specific conditions, reduction of ferredoxin by plastoquinol is possible after a rapid increase in light intensity. Further analysis also revealed that the relationship between ATP synthesis and proton motive force was highly regulated by the concentrations of ATP, ADP, and inorganic phosphate, and this facilitated an increase in nonphotochemical quenching and proton motive force under conditions where metabolism was limiting, such as low CO2, high light intensity, or combined high CO2 and high light intensity. The model may be used as an in silico platform for future research on the regulation of photosynthetic electron transport.
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Affiliation(s)
- Alejandro Morales
- Centre for Crop Systems Analysis, Wageningen University, 6700 AK, Wageningen, The Netherlands
| | - Xinyou Yin
- Centre for Crop Systems Analysis, Wageningen University, 6700 AK, Wageningen, The Netherlands
| | - Jeremy Harbinson
- Horticulture and Product Physiology, Wageningen University, 6700 AA, Wageningen, The Netherlands
| | - Steven M Driever
- Centre for Crop Systems Analysis, Wageningen University, 6700 AK, Wageningen, The Netherlands
| | - Jaap Molenaar
- Biometris, Mathematical and Statistical Methods Group, Wageningen University, 6700 AA, Wageningen, The Netherlands
| | - David M Kramer
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48823
| | - Paul C Struik
- Centre for Crop Systems Analysis, Wageningen University, 6700 AK, Wageningen, The Netherlands
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116
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Kaiser E, Morales A, Harbinson J. Fluctuating Light Takes Crop Photosynthesis on a Rollercoaster Ride. PLANT PHYSIOLOGY 2018; 176:977-989. [PMID: 29046421 PMCID: PMC5813579 DOI: 10.1104/pp.17.01250] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/16/2017] [Indexed: 05/18/2023]
Abstract
Crops are regularly exposed to frequent irradiance fluctuations, which decrease their integrated CO2 assimilation and affect their phenotype.
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Affiliation(s)
- Elias Kaiser
- Horticulture and Product Physiology Group, Wageningen University, 6700 AA Wageningen, The Netherlands
| | - Alejandro Morales
- Centre for Crop Systems Analysis, Wageningen University, 6700 AK Wageningen, The Netherlands
| | - Jeremy Harbinson
- Horticulture and Product Physiology Group, Wageningen University, 6700 AA Wageningen, The Netherlands
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117
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Slattery RA, Walker BJ, Weber APM, Ort DR. The Impacts of Fluctuating Light on Crop Performance. PLANT PHYSIOLOGY 2018; 176:990-1003. [PMID: 29192028 PMCID: PMC5813574 DOI: 10.1104/pp.17.01234] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 11/27/2017] [Indexed: 05/18/2023]
Abstract
Rapidly changing light conditions can reduce carbon gain and productivity in field crops because photosynthetic responses to light fluctuations are not instantaneous. Plant responses to fluctuating light occur across levels of organizational complexity from entire canopies to the biochemistry of a single reaction and across orders of magnitude of time. Although light availability and variation at the top of the canopy are largely dependent on the solar angle and degree of cloudiness, lower crop canopies rely more heavily on light in the form of sunflecks, the quantity of which depends mostly on canopy structure but also may be affected by wind. The ability of leaf photosynthesis to respond rapidly to these variations in light intensity is restricted by the relatively slow opening/closing of stomata, activation/deactivation of C3 cycle enzymes, and up-regulation/down-regulation of photoprotective processes. The metabolic complexity of C4 photosynthesis creates the apparently contradictory possibilities that C4 photosynthesis may be both more and less resilient than C3 to dynamic light regimes, depending on the frequency at which these light fluctuations occur. We review the current understanding of the underlying mechanisms of these limitations to photosynthesis in fluctuating light that have shown promise in improving the response times of photosynthesis-related processes to changes in light intensity.
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Affiliation(s)
- Rebecca A Slattery
- Global Change and Photosynthesis Research Unit, Agricultural Research Service, United States Department of Agriculture, Urbana, Illinois 61801
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801
| | - Berkley J Walker
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences, Heinrich-Heine-University, Duesseldorf, Germany 40225
| | - Andreas P M Weber
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences, Heinrich-Heine-University, Duesseldorf, Germany 40225
| | - Donald R Ort
- Global Change and Photosynthesis Research Unit, Agricultural Research Service, United States Department of Agriculture, Urbana, Illinois 61801
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801
- Department of Plant Biology, University of Illinois, Urbana, Illinois 61801
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118
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Ruiz-Lau N, Sáez Á, Lanza M, Benito B. Genomic and Transcriptomic Compilation of Chloroplast Ionic Transporters of Physcomitrella patens. Study of NHAD Transporters in Na+ and K+ Homeostasis. PLANT & CELL PHYSIOLOGY 2017; 58:2166-2178. [PMID: 29036645 DOI: 10.1093/pcp/pcx150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 09/26/2017] [Indexed: 06/07/2023]
Abstract
K+ is widely used by plant cells, whereas Na+ can easily reach toxic levels during plant growth, which typically occurs in saline environments; however, the effects and functions in the chloroplast have been only roughly estimated. Traditionally, the occurrence of ionic fluxes across the chloroplast envelope or the thylakoid membranes has been mostly deduced from physiological measurements or from knowledge of chloroplast metabolism. However, many of the proteins involved in these fluxes have not yet been characterized. Based on genomic and RNA sequencing (RNA-seq) analyses, we present a comprehensive compilation of genes encoding putative ion transporters and channels expressed in the chloroplasts of the moss Physcomitrella patens, with a special emphasis on those related to Na+ and K+ fluxes. Based on the functional characterization of nhad mutants, we also discuss the putative role of NHAD transporters in Na+ homeostasis and osmoregulation of this organelle and the putative contribution of chloroplasts to salt tolerance in this moss. We demonstrate that NaCl does not affect the chloroplast functionality in Physcomitrella despite significantly modifying expression of ionic transporters and cellular morphology, specifically the chloroplast ultrastructure, revealing a high starch accumulation. Additionally, NHAD transporters apparently do not play any essential roles in salt tolerance.
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Affiliation(s)
- Nancy Ruiz-Lau
- CONACYT-Instituto Tecnológico de Tuxtla Gutiérrez, Carretera Panamericana Km 1080, Terán 29050, Tuxtla Gutiérrez, Chis, México
| | - Ángela Sáez
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo UPM, 28223-Pozuelo de Alarcón (Madrid), Spain
| | - Mónica Lanza
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo UPM, 28223-Pozuelo de Alarcón (Madrid), Spain
| | - Begoña Benito
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo UPM, 28223-Pozuelo de Alarcón (Madrid), Spain
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119
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Kaiser E, Zhou D, Heuvelink E, Harbinson J, Morales A, Marcelis LFM. Elevated CO2 increases photosynthesis in fluctuating irradiance regardless of photosynthetic induction state. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:5629-5640. [PMID: 29045757 PMCID: PMC5853276 DOI: 10.1093/jxb/erx357] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 09/25/2017] [Indexed: 05/18/2023]
Abstract
Leaves are often exposed to fluctuating irradiance, which limits assimilation. Elevated CO2 enhances dynamic photosynthesis (i.e. photosynthesis in fluctuating irradiance) beyond its effects on steady-state photosynthesis rates. Studying the role of CO2 in dynamic photosynthesis is important for understanding plant responses to changing atmospheric CO2 partial pressures. The rise of photosynthesis after a step-wise increase to 1000 μmol m-2 s-1, the loss of photosynthetic induction after irradiance decreases, and rates of photosynthesis during sinusoidal changes in irradiance were studied in tomato (Solanum lycopersicum L.) leaves, using three CO2 partial pressures (200, 400, and 800 µbar). Initial irradiance was set to 0, 50, 100, and 200 μmol m-2 s-1 to vary the initial induction state. Most responses at 200 µbar were not different from those at 400 µbar. In contrast, CO2 at 800 µbar increased the relative carbon gain by 12% after an increase in irradiance, decreased the loss of photosynthetic induction by 14%, and increased dynamic photosynthesis during sine waves by 17%, compared with 400 µbar. These effects were additional to steady-state effects of elevated CO2 on photosynthesis. The enhancement of dynamic photosynthesis rates by elevated CO2 may therefore additionally increase photosynthesis in a future, CO2-enriched climate.
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Affiliation(s)
- Elias Kaiser
- Horticulture and Product Physiology, Department of Plant Sciences, Wageningen University, AA Wageningen, The Netherlands
- Correspondence:
| | - Dianfan Zhou
- Horticulture and Product Physiology, Department of Plant Sciences, Wageningen University, AA Wageningen, The Netherlands
| | - Ep Heuvelink
- Horticulture and Product Physiology, Department of Plant Sciences, Wageningen University, AA Wageningen, The Netherlands
| | - Jeremy Harbinson
- Horticulture and Product Physiology, Department of Plant Sciences, Wageningen University, AA Wageningen, The Netherlands
| | - Alejandro Morales
- Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University, AK Wageningen, The Netherlands
| | - Leo F M Marcelis
- Horticulture and Product Physiology, Department of Plant Sciences, Wageningen University, AA Wageningen, The Netherlands
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120
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Wang Y, Wu WH. Regulation of potassium transport and signaling in plants. CURRENT OPINION IN PLANT BIOLOGY 2017; 39:123-128. [PMID: 28710919 DOI: 10.1016/j.pbi.2017.06.006] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 06/12/2017] [Accepted: 06/12/2017] [Indexed: 05/06/2023]
Abstract
As an essential macronutrient, potassium (K+) plays crucial roles in diverse physiological processes during plant growth and development. The K+ concentration in soils is relatively low and fluctuating. Plants are able to perceive external K+ changes and generate chemical and physical signals in plant cells. The signals can be transducted across the plasma membrane and into the cytosol, and eventually regulates the downstream targets, particularly K+ channels and transporters. As a result, K+ homeostasis in plant cells is modulated, which facilitates plant adaptation to K+ deficient conditions. This minireview focuses on the latest research progress in the diverse functions of K+ channels and transporters as well as their regulatory mechanisms in plant response to low-K+ stress.
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Affiliation(s)
- Yi Wang
- State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Wei-Hua Wu
- State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, China Agricultural University, Beijing 100193, China.
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121
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A chloroplast thylakoid lumen protein is required for proper photosynthetic acclimation of plants under fluctuating light environments. Proc Natl Acad Sci U S A 2017; 114:E8110-E8117. [PMID: 28874535 DOI: 10.1073/pnas.1712206114] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Despite our increasingly sophisticated understanding of mechanisms ensuring efficient photosynthesis under laboratory-controlled light conditions, less is known about the regulation of photosynthesis under fluctuating light. This is important because-in nature-photosynthetic organisms experience rapid and extreme changes in sunlight, potentially causing deleterious effects on photosynthetic efficiency and productivity. Here we report that the chloroplast thylakoid lumenal protein MAINTENANCE OF PHOTOSYSTEM II UNDER HIGH LIGHT 2 (MPH2; encoded by At4g02530) is required for growth acclimation of Arabidopsis thaliana plants under controlled photoinhibitory light and fluctuating light environments. Evidence is presented that mph2 mutant light stress susceptibility results from a defect in photosystem II (PSII) repair, and our results are consistent with the hypothesis that MPH2 is involved in disassembling monomeric complexes during regeneration of dimeric functional PSII supercomplexes. Moreover, mph2-and previously characterized PSII repair-defective mutants-exhibited reduced growth under fluctuating light conditions, while PSII photoprotection-impaired mutants did not. These findings suggest that repair is not only required for PSII maintenance under static high-irradiance light conditions but is also a regulatory mechanism facilitating photosynthetic adaptation under fluctuating light environments. This work has implications for improvement of agricultural plant productivity through engineering PSII repair.
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122
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Spetea C, Herdean A, Allorent G, Carraretto L, Finazzi G, Szabo I. An update on the regulation of photosynthesis by thylakoid ion channels and transporters in Arabidopsis. PHYSIOLOGIA PLANTARUM 2017; 161:16-27. [PMID: 28332210 DOI: 10.1111/ppl.12568] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/08/2017] [Accepted: 02/20/2017] [Indexed: 05/07/2023]
Abstract
In natural, variable environments, plants rapidly adjust photosynthesis for optimal balance between light absorption and utilization. There is increasing evidence suggesting that ion fluxes across the chloroplast thylakoid membrane play an important role in this regulation by affecting the proton motive force and consequently photosynthesis and thylakoid membrane ultrastructure. This article presents an update on the thylakoid ion channels and transporters characterized in Arabidopsis thaliana as being involved in these processes, as well as an outlook at the evolutionary conservation of their functions in other photosynthetic organisms. This is a contribution to shed light on the thylakoid network of ion fluxes and how they help plants to adjust photosynthesis in variable light environments.
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Affiliation(s)
- Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, 40530, Sweden
| | - Andrei Herdean
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, 40530, Sweden
| | - Guillaume Allorent
- Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, Centre National de la Recherche Scientifique (CNRS), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut National Recherche Agronomique (INRA), Institut de Biosciences et Biotechnologie de Grenoble (BIG), Université Grenoble Alpes (UGA), Grenoble, 38100, France
| | - Luca Carraretto
- Department of Biology, University of Padova, Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy
| | - Giovanni Finazzi
- Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, Centre National de la Recherche Scientifique (CNRS), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut National Recherche Agronomique (INRA), Institut de Biosciences et Biotechnologie de Grenoble (BIG), Université Grenoble Alpes (UGA), Grenoble, 38100, France
| | - Ildikò Szabo
- Department of Biology, University of Padova, Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy
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123
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Ahmad RA, Dietzel L. Relaxation of cellular K + gradients by valinomycin induces diatoxanthin accumulation in Cyclotella meneghiniana cells and alters FCPa fluorescence yield in vitro. PHYSIOLOGIA PLANTARUM 2017; 161:171-180. [PMID: 28664565 DOI: 10.1111/ppl.12599] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/14/2017] [Accepted: 06/23/2017] [Indexed: 06/07/2023]
Abstract
Regulation of photosynthetic light harvesting involves all major thylakoid membrane complexes. One important factor is the proton motive force (pmf) driving ATP production. Its proton gradient (ΔpH) component regulates the high energy quenching. Potassium ions largely contribute to the formation of the electric field (ΔΨ). ΔΨ and ΔpH partially compensate each other to form pmf. Whilst in plants considerable progress has been made in analyzing the interplay of H+ and K+ gradients, in diatoms knowledge in this field is still scarce. We relaxed cellular K+ gradients by valinomycin in Cyclotella meneghiniana. We observed a slow decrease of PSII maximum quantum yield in the dark upon valinomycin addition correlating with diatoxanthin accumulation which we attribute to the breakdown of organellar K+ gradients (either plastid or mitochondria) which might compensate for the loss of the K+ gradient by adjustment of the thylakoid pH in a secondary step. This response is reversible when ΔpH is relaxed. Similarly, we found higher non-photochemical quenching (NPQ) caused by higher DT accumulation in the steady state in valinomycin-treated cells. In vitro fucoxanthin chlorophyll a (FCPa) antenna complexes in liposomes with natural lipid composition showed a decrease in fluorescence yield if a K+ gradient is built up. The effect reversed by relaxing the gradient. We interpret these fluorescence changes with surface charge dynamics and FCPa organization in the membrane rather than a direct influence of K+ gradients on FCPa complexes. Both experiments reveal that K+ gradients might contribute to fine tuning of light harvesting capacity in relation to pmf in diatoms.
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Affiliation(s)
- Rana A Ahmad
- Institute of Molecular Biosciences, Department of Plant Cell Physiology, Goethe University Frankfurt, Frankfurt 60438, Germany
| | - Lars Dietzel
- Institute of Molecular Biosciences, Department of Plant Cell Physiology, Goethe University Frankfurt, Frankfurt 60438, Germany
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124
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Crisp PA, Ganguly DR, Smith AB, Murray KD, Estavillo GM, Searle I, Ford E, Bogdanović O, Lister R, Borevitz JO, Eichten SR, Pogson BJ. Rapid Recovery Gene Downregulation during Excess-Light Stress and Recovery in Arabidopsis. THE PLANT CELL 2017; 29:1836-1863. [PMID: 28705956 PMCID: PMC5590493 DOI: 10.1105/tpc.16.00828] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 06/22/2017] [Accepted: 07/11/2017] [Indexed: 05/19/2023]
Abstract
Stress recovery may prove to be a promising approach to increase plant performance and, theoretically, mRNA instability may facilitate faster recovery. Transcriptome (RNA-seq, qPCR, sRNA-seq, and PARE) and methylome profiling during repeated excess-light stress and recovery was performed at intervals as short as 3 min. We demonstrate that 87% of the stress-upregulated mRNAs analyzed exhibit very rapid recovery. For instance, HSP101 abundance declined 2-fold every 5.1 min. We term this phenomenon rapid recovery gene downregulation (RRGD), whereby mRNA abundance rapidly decreases promoting transcriptome resetting. Decay constants (k) were modeled using two strategies, linear and nonlinear least squares regressions, with the latter accounting for both transcription and degradation. This revealed extremely short half-lives ranging from 2.7 to 60.0 min for 222 genes. Ribosome footprinting using degradome data demonstrated RRGD loci undergo cotranslational decay and identified changes in the ribosome stalling index during stress and recovery. However, small RNAs and 5'-3' RNA decay were not essential for recovery of the transcripts examined, nor were any of the six excess light-associated methylome changes. We observed recovery-specific gene expression networks upon return to favorable conditions and six transcriptional memory types. In summary, rapid transcriptome resetting is reported in the context of active recovery and cellular memory.
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Affiliation(s)
- Peter A Crisp
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University Canberra, Acton ACT 0200, Australia
- Department of Plant and Microbial Biology, University of Minnesota, Saint Paul, Minnesota 55108
| | - Diep R Ganguly
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University Canberra, Acton ACT 0200, Australia
| | - Aaron B Smith
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University Canberra, Acton ACT 0200, Australia
| | - Kevin D Murray
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University Canberra, Acton ACT 0200, Australia
| | - Gonzalo M Estavillo
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University Canberra, Acton ACT 0200, Australia
- CSIRO Agriculture and Food, Black Mountain, Canberra ACT 2601, Australia
| | - Iain Searle
- School of Biological Sciences, The University of Adelaide, SA 5005, Australia
| | - Ethan Ford
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth WA 6009, Australia
| | - Ozren Bogdanović
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth WA 6009, Australia
- Harry Perkins Institute of Medical Research, Perth WA 6009, Australia
| | - Ryan Lister
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth WA 6009, Australia
- Harry Perkins Institute of Medical Research, Perth WA 6009, Australia
| | - Justin O Borevitz
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University Canberra, Acton ACT 0200, Australia
| | - Steven R Eichten
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University Canberra, Acton ACT 0200, Australia
| | - Barry J Pogson
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University Canberra, Acton ACT 0200, Australia
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Takagi D, Amako K, Hashiguchi M, Fukaki H, Ishizaki K, Goh T, Fukao Y, Sano R, Kurata T, Demura T, Sawa S, Miyake C. Chloroplastic ATP synthase builds up a proton motive force preventing production of reactive oxygen species in photosystem I. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 91:306-324. [PMID: 28380278 DOI: 10.1111/tpj.13566] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 03/29/2017] [Accepted: 04/03/2017] [Indexed: 05/19/2023]
Abstract
Over-reduction of the photosynthetic electron transport (PET) chain should be avoided, because the accumulation of reducing electron carriers produces reactive oxygen species (ROS) within photosystem I (PSI) in thylakoid membranes and causes oxidative damage to chloroplasts. To prevent production of ROS in thylakoid membranes the H+ gradient (ΔpH) needs to be built up across the thylakoid membranes to suppress the over-reduction state of the PET chain. In this study, we aimed to identify the critical component that stimulates ΔpH formation under illumination in higher plants. To do this, we screened ethyl methane sulfonate (EMS)-treated Arabidopsis thaliana, in which the formation of ΔpH is impaired and the PET chain caused over-reduction under illumination. Subsequently, we isolated an allelic mutant that carries a missense mutation in the γ-subunit of chloroplastic CF0 CF1 -ATP synthase, named hope2. We found that hope2 suppressed the formation of ΔpH during photosynthesis because of the high H+ efflux activity from the lumenal to stromal side of the thylakoid membranes via CF0 CF1 -ATP synthase. Furthermore, PSI was in a more reduced state in hope2 than in wild-type (WT) plants, and hope2 was more vulnerable to PSI photoinhibition than WT under illumination. These results suggested that chloroplastic CF0 CF1 -ATP synthase adjusts the redox state of the PET chain, especially for PSI, by modulating H+ efflux activity across the thylakoid membranes. Our findings suggest the importance of the buildup of ΔpH depending on CF0 CF1 -ATP synthase to adjust the redox state of the reaction center chlorophyll P700 in PSI and to suppress the production of ROS in PSI during photosynthesis.
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Affiliation(s)
- Daisuke Takagi
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, 7 Gobancho, Chiyoda-ku, Tokyo, 102-0076, Japan
| | - Katsumi Amako
- Faculty of Nutrition, Kobe Gakuin University, Kobe, 651-2180, Japan
| | - Masaki Hashiguchi
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
| | - Hidehiro Fukaki
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
| | - Kimitsune Ishizaki
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
| | - Tatsuaki Goh
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
| | - Yoichiro Fukao
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, 630-0192, Japan
| | - Ryosuke Sano
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, 630-0192, Japan
| | - Tetsuya Kurata
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, 630-0192, Japan
- Graduate School of Life Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 980-8578, Japan
| | - Taku Demura
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, 630-0192, Japan
| | - Shinichiro Sawa
- Graduate School of Science and Technology, Kumamoto University, Kurokami, Tyuou-ku, Kumamoto, 860-8555, Japan
| | - Chikahiro Miyake
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, 7 Gobancho, Chiyoda-ku, Tokyo, 102-0076, Japan
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126
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Szabò I, Spetea C. Impact of the ion transportome of chloroplasts on the optimization of photosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3115-3128. [PMID: 28338935 DOI: 10.1093/jxb/erx063] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Ions play fundamental roles in all living cells, and their gradients are often essential to fuel transport, regulate enzyme activities, and transduce energy within cells. Regulation of their homeostasis is essential for cell metabolism. Recent results indicate that modulation of ion fluxes might also represent a useful strategy to regulate one of the most important physiological processes taking place in chloroplasts, photosynthesis. Photosynthesis is highly regulated, due to its unique role as a cellular engine for growth in the light. Controlling the balance between ATP and NADPH synthesis is a critical task, and availability of these molecules can limit the overall photosynthetic yield. Photosynthetic organisms optimize photosynthesis in low light, where excitation energy limits CO2 fixation, and minimize photo-oxidative damage in high light by dissipating excess photons. Despite extensive studies of these phenomena, the mechanism governing light utilization in plants is still poorly understood. In this review, we provide an update of the recently identified chloroplast-located ion channels and transporters whose function impacts photosynthetic efficiency in plants.
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Affiliation(s)
- Ildikò Szabò
- Department of Biology, University of Padova, Italy; CNR Institute of Neuroscience, Padova, Italy
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, 40530 Gothenburg, Sweden
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127
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Bose J, Munns R, Shabala S, Gilliham M, Pogson B, Tyerman SD. Chloroplast function and ion regulation in plants growing on saline soils: lessons from halophytes. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3129-3143. [PMID: 28472512 DOI: 10.1093/jxb/erx142] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Salt stress impacts multiple aspects of plant metabolism and physiology. For instance it inhibits photosynthesis through stomatal limitation, causes excessive accumulation of sodium and chloride in chloroplasts, and disturbs chloroplast potassium homeostasis. Most research on salt stress has focused primarily on cytosolic ion homeostasis with few studies of how salt stress affects chloroplast ion homeostasis. This review asks the question whether membrane-transport processes and ionic relations are differentially regulated between glycophyte and halophyte chloroplasts and whether this contributes to the superior salt tolerance of halophytes. The available literature indicates that halophytes can overcome stomatal limitation by switching to CO2 concentrating mechanisms and increasing the number of chloroplasts per cell under saline conditions. Furthermore, salt entry into the chloroplast stroma may be critical for grana formation and photosystem II activity in halophytes but not in glycophytes. Salt also inhibits some stromal enzymes (e.g. fructose-1,6-bisphosphatase) to a lesser extent in halophyte species. Halophytes accumulate more chloride in chloroplasts than glycophytes and appear to use sodium in functional roles. We propose the molecular identities of candidate transporters that move sodium, chloride and potassium across chloroplast membranes and discuss how their operation may regulate photochemistry and photosystem I and II activity in chloroplasts.
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Affiliation(s)
- Jayakumar Bose
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
| | - Rana Munns
- Australian Research Council Centre of Excellence in Plant Energy Biology, and School of Agriculture and Environment, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Sergey Shabala
- School of Land and Food, University of Tasmania, Private Bag 54, Hobart, TAS 7001, Australia
| | - Matthew Gilliham
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
| | - Barry Pogson
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Stephen D Tyerman
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
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128
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Armbruster U, Correa Galvis V, Kunz HH, Strand DD. The regulation of the chloroplast proton motive force plays a key role for photosynthesis in fluctuating light. CURRENT OPINION IN PLANT BIOLOGY 2017; 37:56-62. [PMID: 28426975 DOI: 10.1016/j.pbi.2017.03.012] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/23/2017] [Accepted: 03/24/2017] [Indexed: 05/22/2023]
Abstract
Plants use sunlight as their primary energy source. During photosynthesis, absorbed light energy generates reducing power by driving electron transfer reactions. These are coupled to the transfer of protons into the thylakoid lumen, generating a proton motive force (pmf) required for ATP synthesis. Sudden alterations in light availability have to be met by regulatory mechanisms to avoid the over-accumulation of reactive intermediates and maximize energy efficiency. Here, the acidification of the lumen, as an intermediate product of photosynthesis, plays an important role by regulating photosynthesis in response to excitation energy levels. Recent findings reveal pmf regulation and the modulation of its composition as key determinants for efficient photosynthesis, plant growth, and survival in fluctuating light environments.
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Affiliation(s)
- Ute Armbruster
- Regulation of Photosynthesis Group, Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany.
| | - Viviana Correa Galvis
- Regulation of Photosynthesis Group, Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Hans-Henning Kunz
- Plant Physiology, School of Biological Sciences, Washington State University, P.O. Box 644236, Pullman, WA 99164-4236, USA
| | - Deserah D Strand
- Organelle Biology and Biotechnology Group, Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
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129
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Alric J, Johnson X. Alternative electron transport pathways in photosynthesis: a confluence of regulation. CURRENT OPINION IN PLANT BIOLOGY 2017; 37:78-86. [PMID: 28426976 DOI: 10.1016/j.pbi.2017.03.014] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/23/2017] [Accepted: 03/28/2017] [Indexed: 05/19/2023]
Abstract
Photosynthetic reactions proceed along a linear electron transfer chain linking water oxidation at photosystem II (PSII) to CO2 reduction in the Calvin-Benson-Bassham cycle. Alternative pathways poise the electron carriers along the chain in response to changing light, temperature and CO2 inputs, under prolonged hydration stress and during development. We describe recent literature that reports the physiological functions of new molecular players. Such highlights include the flavodiiron proteins and their important role in the green lineage. The parsing of the proton-motive force between ΔpH and Δψ, regulated in many different ways (cyclic electron flow, ATPsynthase conductivity, ion/H+ transporters), is comprehensively reported. This review focuses on an integrated description of alternative electron transfer pathways and how they contribute to photosynthetic productivity in the context of plant fitness to the environment.
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Affiliation(s)
- Jean Alric
- CEA, CNRS, Aix-Marseille Université, Institut de Biosciences et Biotechnologies Aix-Marseille, UMR 7265, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, Saint-Paul-lez-Durance F-13108, France
| | - Xenie Johnson
- CEA, CNRS, Aix-Marseille Université, Institut de Biosciences et Biotechnologies Aix-Marseille, UMR 7265, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, Saint-Paul-lez-Durance F-13108, France.
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130
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Rehman HM, Nawaz MA, Shah ZH, Daur I, Khatoon S, Yang SH, Chung G. In-Depth Genomic and Transcriptomic Analysis of Five K + Transporter Gene Families in Soybean Confirm Their Differential Expression for Nodulation. FRONTIERS IN PLANT SCIENCE 2017; 8:804. [PMID: 28588592 PMCID: PMC5440519 DOI: 10.3389/fpls.2017.00804] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 04/28/2017] [Indexed: 05/27/2023]
Abstract
Plants have evolved a sophisticated network of K+ transport systems to regulate growth and development. Limited K+ resources are now forcing us to investigate how plant demand can be satisfied. To answer this complex question, we must understand the genomic and transcriptomic portfolio of K+ transporters in plants. Here, we have identified 70 putative K+ transporter genes from soybean, including 29 HAK/KT/KUP genes, 16 genes encoding voltage-gated K+ channels, 9 TPK/KCO genes, 4 HKT genes, and 12 KEA genes. To clarify the molecular evolution of each family in soybean, we analyzed their phylogeny, mode of duplication, exon structures and splice sites, and paralogs. Additionally, ortholog clustering and syntenic analysis across five other dicots further explored the evolution of these gene families and indicated that the soybean data is suitable as a model for all other legumes. Available microarray data sets from Genevestigator about nodulation was evaluated and further confirmed with the RNA sequencing data available by a web server. For each family, expression models were designed based on Transcripts Per Kilobase Million (TPM) values; the outcomes indicated differential expression linked to nodulation and confirmed the genes' putative roles. In-depth studies such as ours provides the basis for understanding K+ inventories in all other plants.
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Affiliation(s)
- Hafiz M. Rehman
- Department of Biotechnology, Chonnam National UniversityYeosu, South Korea
| | - Muhammad A. Nawaz
- Department of Biotechnology, Chonnam National UniversityYeosu, South Korea
| | - Zahid Hussain Shah
- Department of Arid Land Agriculture, King Abdul-Aziz UniversityJeddah, Saudi Arabia
| | - Ihsanullah Daur
- Department of Arid Land Agriculture, King Abdul-Aziz UniversityJeddah, Saudi Arabia
| | - Sadia Khatoon
- Department of Biosciences, University of WahWah Cantt, Pakistan
| | - Seung Hwan Yang
- Department of Biotechnology, Chonnam National UniversityYeosu, South Korea
| | - Gyuhwa Chung
- Department of Biotechnology, Chonnam National UniversityYeosu, South Korea
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131
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Hoecker N, Leister D, Schneider A. Plants contain small families of UPF0016 proteins including the PHOTOSYNTHESIS AFFECTED MUTANT71 transporter. PLANT SIGNALING & BEHAVIOR 2017; 12:e1278101. [PMID: 28075225 PMCID: PMC5351731 DOI: 10.1080/15592324.2016.1278101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
PHOTOSYNTHESIS AFFECTED MUTANT71 (PAM71) is an integral thylakoid membrane protein that functions in manganese uptake into the lumen. Manganese is needed in the thylakoid lumen to build up the inorganic Mn4CaO5 cluster, the catalytic center for water oxidation, and is hence indispensable for oxygen evolution. A recent study revealed that PAM71 is well conserved in plants and shares homology to GCR1 DEPENDENT TRANSLATION FACTOR1 (GDT1) and TRANSMEMBRANE PROTEIN 165 (TMEM165) in Saccharomyces cerevisiae and Homo sapiens, respectively. In most eukaryotes only single members of this family, designated "Uncharacterized Protein Family 0016" (UPF0016), are present; however, plant genomes contain genes for several UPF0016 proteins. In Arabidopsis thaliana, this protein family comprises 5 members, which mainly differ in their N-terminal regions. PAM71 and its closest homolog PAM71-HL possess chloroplast transit peptides at their N-terminus. Two of the remaining 3 members are derived from a segmental chromosomal duplication event and lack an N-terminal extension. Thus, plants have evolved UPF0016 members residing in various compartments of the cell, whereas in non-plant eukaryotes just a Golgi localization occurs. The identification of PAM71 as a candidate Mn2+ transporter opens the question on the function of the remaining plant members. Here we resume briefly our current knowledge of UPF0016 members in Arabidopsis in comparison to their yeast and human UPF0016 members.
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Affiliation(s)
- Natalie Hoecker
- Department of Biology I, Plant Sciences, Ludwig-Maximilians Universität München, Martinsried, Germany
| | - Dario Leister
- Department of Biology I, Plant Sciences, Ludwig-Maximilians Universität München, Martinsried, Germany
| | - Anja Schneider
- Department of Biology I, Plant Sciences, Ludwig-Maximilians Universität München, Martinsried, Germany
- CONTACT Anja Schneider
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132
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Wang C, Yamamoto H, Narumiya F, Munekage YN, Finazzi G, Szabo I, Shikanai T. Fine-tuned regulation of the K + /H + antiporter KEA3 is required to optimize photosynthesis during induction. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 89:540-553. [PMID: 27783435 DOI: 10.1111/tpj.13405] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 10/17/2016] [Accepted: 10/17/2016] [Indexed: 05/22/2023]
Abstract
KEA3 is a thylakoid membrane localized K+ /H+ antiporter that regulates photosynthesis by modulating two components of proton motive force (pmf), the proton gradient (∆pH) and the electric potential (∆ψ). We identified a mutant allele of KEA3, disturbed proton gradient regulation (dpgr) based on its reduced non-photochemical quenching (NPQ) in artificial (CO2 -free with low O2 ) air. This phenotype was enhanced in the mutant backgrounds of PSI cyclic electron transport (pgr5 and crr2-1). In ambient air, reduced NPQ was observed during induction of photosynthesis in dpgr, the phenotype that was enhanced after overnight dark adaptation. In contrast, the knockout allele of kea3-1 exhibited a high-NPQ phenotype during steady state in ambient air. Consistent with this kea3-1 phenotype in ambient air, the membrane topology of KEA3 indicated a proton efflux from the thylakoid lumen to the stroma. The dpgr heterozygotes showed a semidominant and dominant phenotype in artificial and ambient air, respectively. In dpgr, the protein level of KEA3 was unaffected but the downregulation of its activity was probably disturbed. Our findings suggest that fine regulation of KEA3 activity is necessary for optimizing photosynthesis.
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Affiliation(s)
- Caijuan Wang
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
- CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo, 102-0076, Japan
| | - Fumika Narumiya
- Graduate School of Sciences, Nara Institute of Science and Technology, Ikoma, Nara, 630-0101, Japan
- Sakai City Institute of Public Health, Sakai, Osaka, 590-0953, Japan
| | - Yuri Nakajima Munekage
- Graduate School of Sciences, Nara Institute of Science and Technology, Ikoma, Nara, 630-0101, Japan
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sandan, Hyogo, 669-1337, Japan
| | - Giovanni Finazzi
- UMR 5168 Laboratoire de Physiologie Cellulaire Végétale (LPCV) CNRS/UJF/INRA/CEA, Institut de Recherches en Technologies et Sciences pour le Vivant (iRTSV), CEA Grenoble, 38054, Grenoble, France
| | - Ildiko Szabo
- Department of Biology, University of Padova, Padova, 35121, Italy
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
- CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo, 102-0076, Japan
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133
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Shikanai T, Yamamoto H. Contribution of Cyclic and Pseudo-cyclic Electron Transport to the Formation of Proton Motive Force in Chloroplasts. MOLECULAR PLANT 2017; 10:20-29. [PMID: 27575692 DOI: 10.1016/j.molp.2016.08.004] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 07/28/2016] [Accepted: 08/08/2016] [Indexed: 05/05/2023]
Abstract
Photosynthetic electron transport is coupled to proton translocation across the thylakoid membrane, resulting in the formation of a trans-thylakoid proton gradient (ΔpH) and membrane potential (Δψ). Ion transporters and channels localized to the thylakoid membrane regulate the contribution of each component to the proton motive force (pmf). Although both ΔpH and Δψ contribute to ATP synthesis as pmf, only ΔpH downregulates photosynthetic electron transport via the acidification of the thylakoid lumen by inducing thermal dissipation of excessive absorbed light energy from photosystem II antennae and slowing down of the electron transport through the cytochrome b6f complex. To optimize the tradeoff between efficient light energy utilization and protection of both photosystems against photodamage, plants have to regulate the pmf amplitude and its components, ΔpH and Δψ. Cyclic electron transport around photosystem I (PSI) is a major regulator of the pmf amplitude by generating pmf independently of the net production of NADPH by linear electron transport. Chloroplast ATP synthase relaxes pmf for ATP synthesis, and its activity should be finely tuned for maintaining the size of the pmf during steady-state photosynthesis. Pseudo-cyclic electron transport mediated by flavodiiron protein (Flv) forms a large electron sink, which is essential for PSI photoprotection in fluctuating light in cyanobacteria. Flv is conserved from cyanobacteria to gymnosperms but not in angiosperms. The Arabidopsis proton gradient regulation 5 (pgr5) mutant is defective in the main pathway of PSI cyclic electron transport. By introducing Physcomitrella patens genes encoding Flvs, the function of PSI cyclic electron transport was substituted by that of Flv-dependent pseudo-cyclic electron transport. In transgenic plants, the size of the pmf was complemented to the wild-type level but the contribution of ΔpH to the total pmf was lower than that in the wild type. In the pgr5 mutant, the size of the pmf was drastically lowered by the absence of PSI cyclic electron transport. In the mutant, ΔpH occupied the majority of pmf, suggesting the presence of a mechanism for the homeostasis of luminal pH in the light. To avoid damage to photosynthetic electron transport by periods of excess solar energy, plants employ an intricate regulatory network involving alternative electron transport pathways, ion transporters/channels, and pH-dependent mechanisms for downregulating photosynthetic electron transport.
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Affiliation(s)
- Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 Japan; CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076 Japan.
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 Japan; CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076 Japan
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134
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Thormählen I, Zupok A, Rescher J, Leger J, Weissenberger S, Groysman J, Orwat A, Chatel-Innocenti G, Issakidis-Bourguet E, Armbruster U, Geigenberger P. Thioredoxins Play a Crucial Role in Dynamic Acclimation of Photosynthesis in Fluctuating Light. MOLECULAR PLANT 2017; 10:168-182. [PMID: 27940305 DOI: 10.1016/j.molp.2016.11.012] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 11/14/2016] [Accepted: 11/24/2016] [Indexed: 05/22/2023]
Abstract
Sunlight represents the energy source for photosynthesis and plant growth. When growing in the field, plant photosynthesis has to manage strong fluctuations in light intensities. Regulation based on the thioredoxin (Trx) system is believed to ensure light-responsive control of photosynthetic reactions in the chloroplast. However, direct evidence for a role of this system in regulating dynamic acclimation of photosynthesis in fluctuating conditions is largely lacking. In this report we show that the ferredoxin-dependent Trxs m1 and m2 as well as the NADPH-dependent NTRC are both indispensable for photosynthetic acclimation in fluctuating light intensities. Arabidopsis mutants with combined deficiency in Trxs m1 and m2 show wild-type growth and photosynthesis under constant light condition, while photosynthetic parameters are strongly modified in rapidly alternating high and low light. Two independent trxm1m2 mutants show lower photosynthetic efficiency in high light, but surprisingly significantly higher photosynthetic efficiency in low light. Our data suggest that a main target of Trx m1 and m2 is the NADP-malate dehydrogenase involved in export of excess reductive power from the chloroplast. The decreased photosynthetic efficiency in the high-light peaks may thus be explained by a reduced capacity of the trxm1m2 mutants in the rapid light activation of this enzyme. In the ntrc mutant, dynamic responses of non-photochemical quenching of excitation energy and plastoquinone reduction state both were strongly attenuated in fluctuating light intensities, leading to a massive decrease in PSII quantum efficiency and a specific decrease in plant growth under these conditions. This is likely due to the decreased ability of the ntrc mutant to control the stromal NADP(H) redox poise. Taken together, our results indicate that NTRC is indispensable in ensuring the full range of dynamic responses of photosynthesis to optimize photosynthesis and maintain growth in fluctuating light, while Trxs m1 and m2 are indispensable for full activation of photosynthesis in the high-light periods but negatively affect photosynthetic efficiency in the low-light periods of fluctuating light.
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Affiliation(s)
- Ina Thormählen
- Department Biologie I, Ludwig-Maximilians-Universität München, Grosshaderner Straße 2-4, 82152 Martinsried, Germany
| | - Arkadiusz Zupok
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Department 3, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Josephin Rescher
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Department 3, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Jochen Leger
- Department Biologie I, Ludwig-Maximilians-Universität München, Grosshaderner Straße 2-4, 82152 Martinsried, Germany
| | - Stefan Weissenberger
- Department Biologie I, Ludwig-Maximilians-Universität München, Grosshaderner Straße 2-4, 82152 Martinsried, Germany
| | - Julia Groysman
- Department Biologie I, Ludwig-Maximilians-Universität München, Grosshaderner Straße 2-4, 82152 Martinsried, Germany
| | - Anne Orwat
- Department Biologie I, Ludwig-Maximilians-Universität München, Grosshaderner Straße 2-4, 82152 Martinsried, Germany
| | - Gilles Chatel-Innocenti
- Institute of Plant Sciences Paris Saclay (IPS2), UMR 9213/UMR1403, Université Paris Sud, CNRS, INRA, Université d'Evry, Université Paris Diderot, Sorbonne Paris Cité, Bâtiment 630, 91405 Orsay, France
| | - Emmanuelle Issakidis-Bourguet
- Institute of Plant Sciences Paris Saclay (IPS2), UMR 9213/UMR1403, Université Paris Sud, CNRS, INRA, Université d'Evry, Université Paris Diderot, Sorbonne Paris Cité, Bâtiment 630, 91405 Orsay, France
| | - Ute Armbruster
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Department 3, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Peter Geigenberger
- Department Biologie I, Ludwig-Maximilians-Universität München, Grosshaderner Straße 2-4, 82152 Martinsried, Germany.
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135
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Kress E, Jahns P. The Dynamics of Energy Dissipation and Xanthophyll Conversion in Arabidopsis Indicate an Indirect Photoprotective Role of Zeaxanthin in Slowly Inducible and Relaxing Components of Non-photochemical Quenching of Excitation Energy. FRONTIERS IN PLANT SCIENCE 2017; 8:2094. [PMID: 29276525 PMCID: PMC5727089 DOI: 10.3389/fpls.2017.02094] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 11/24/2017] [Indexed: 05/03/2023]
Abstract
The dynamics of non-photochemical quenching (NPQ) of chlorophyll fluorescence and the dynamics of xanthophyll conversion under different actinic light conditions were studied in intact leaves of Arabidopsis thaliana. NPQ induction was investigated during up to 180 min illumination at 450, 900, and 1,800 μmol photons m-2 s-1 (μE) and NPQ relaxation after 5, 30, 90, or 180 min of pre-illumination at the same light intensities. The comparison of wild-type plants with mutants affected either in xanthophyll conversion (npq1 and npq2) or PsbS expression (npq4 and L17) or lumen acidification (pgr1) indicated that NPQ states with similar, but not identical characteristics are induced at longer time range (15-60 min) in wild-type and mutant plants. In genotypes with an active xanthophyll conversion, the dynamics of two slowly (10-60 min) inducible and relaxing NPQ components were found to be kinetically correlated with zeaxanthin formation and epoxidation, respectively. However, the extent of NPQ was independent of the amount of zeaxanthin, since higher NPQ values were inducible with increasing actinic light intensities without pronounced changes in the zeaxanthin amount. These data support an indirect role of zeaxanthin in pH-independent NPQ states rather than a specific direct function of zeaxanthin as quencher in long-lasting NPQ processes. Such an indirect function might be related to an allosteric regulation of NPQ processes by zeaxanthin (e.g., through interaction of zeaxanthin at the surface of proteins) or a general photoprotective function of zeaxanthin in the lipid phase of the membrane (e.g., by modulation of the membrane fluidity or by acting as antioxidant). The found concomitant down-regulation of zeaxanthin epoxidation and recovery of photosystem II activity ensures that zeaxanthin is retained in the thylakoid membrane as long as photosystem II activity is inhibited or down-regulated. This regulation supports the view that zeaxanthin can be considered as a kind of light stress memory in chloroplasts, allowing a rapid reactivation of photoprotective NPQ processes in case of recurrent light stress periods.
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136
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Kaňa R, Govindjee. Role of Ions in the Regulation of Light-Harvesting. FRONTIERS IN PLANT SCIENCE 2016; 7:1849. [PMID: 28018387 PMCID: PMC5160696 DOI: 10.3389/fpls.2016.01849] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/23/2016] [Indexed: 03/03/2024]
Abstract
Regulation of photosynthetic light harvesting in the thylakoids is one of the major key factors affecting the efficiency of photosynthesis. Thylakoid membrane is negatively charged and influences both the structure and the function of the primarily photosynthetic reactions through its electrical double layer (EDL). Further, there is a heterogeneous organization of soluble ions (K+, Mg2+, Cl-) attached to the thylakoid membrane that, together with fixed charges (negatively charged amino acids, lipids), provides an electrical field. The EDL is affected by the valence of the ions and interferes with the regulation of "state transitions," protein interactions, and excitation energy "spillover" from Photosystem II to Photosystem I. These effects are reflected in changes in the intensity of chlorophyll a fluorescence, which is also a measure of photoprotective non-photochemical quenching (NPQ) of the excited state of chlorophyll a. A triggering of NPQ proceeds via lumen acidification that is coupled to the export of positive counter-ions (Mg2+, K+) to the stroma or/and negative ions (e.g., Cl-) into the lumen. The effect of protons and anions in the lumen and of the cations (Mg2+, K+) in the stroma are, thus, functionally tightly interconnected. In this review, we discuss the consequences of the model of EDL, proposed by Barber (1980b) Biochim Biophys Acta 594:253-308) in light of light-harvesting regulation. Further, we explain differences between electrostatic screening and neutralization, and we emphasize the opposite effect of monovalent (K+) and divalent (Mg2+) ions on light-harvesting and on "screening" of the negative charges on the thylakoid membrane; this effect needs to be incorporated in all future models of photosynthetic regulation by ion channels and transporters.
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Affiliation(s)
- Radek Kaňa
- Institute of Microbiology, Academy of Sciences of the CzechiaTřeboň, Czechia
- Faculty of Science, Institute of Chemistry and Biochemistry, University of South BohemiaČeské Budějovice, Czechia
| | - Govindjee
- Center of Biophysics and Quantitative Biology, Department of Biochemistry, Department of Plant Biology, University of Illinois at Urbana-ChampaignUrbana, IL, USA
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137
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Dana S, Herdean A, Lundin B, Spetea C. Each of the chloroplast potassium efflux antiporters affects photosynthesis and growth of fully developed Arabidopsis rosettes under short-day photoperiod. PHYSIOLOGIA PLANTARUM 2016; 158:483-491. [PMID: 27080934 DOI: 10.1111/ppl.12452] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 03/08/2016] [Accepted: 03/12/2016] [Indexed: 06/05/2023]
Abstract
In Arabidopsis thaliana, the chloroplast harbors three potassium efflux antiporters (KEAs), namely KEA1 and KEA2 in the inner envelope and KEA3 in the thylakoid membrane. They may play redundant physiological roles as in our previous analyses of young developing Arabidopsis rosettes under long-day photoperiod (16 h light per day), chloroplast kea single mutants resembled the wild-type plants, whereas kea1kea2 and kea1kea2kea3 mutants were impaired in chloroplast development and photosynthesis resulting in stunted growth. Here, we aimed to study whether chloroplast KEAs play redundant roles in chloroplast function of older Arabidopsis plants with fully developed rosettes grown under short-day photoperiod (8 h light per day). Under these conditions, we found defects in photosynthesis and growth in the chloroplast kea single mutants, and most dramatic defects in the kea1kea2 double mutant. The mechanism behind these defects in the single mutants involves reduction in the electron transport rate (kea1 and kea3), and stomata conductance (kea1, kea2 and kea3), which in turn affect CO2 fixation rates. The kea1kea2 mutant, in addition to these alterations, displayed reduced levels of photosynthetic machinery. Taken together, our data suggest that, in addition to the previously reported roles in chloroplast development in young rosettes, each chloroplast KEA affects photosynthesis and growth of Arabidopsis fully developed rosettes.
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Affiliation(s)
- Somnath Dana
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Andrei Herdean
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Björn Lundin
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
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138
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Berthouly-Salazar C, Thuillet AC, Rhoné B, Mariac C, Ousseini IS, Couderc M, Tenaillon MI, Vigouroux Y. Genome scan reveals selection acting on genes linked to stress response in wild pearl millet. Mol Ecol 2016; 25:5500-5512. [PMID: 27664976 DOI: 10.1111/mec.13859] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 09/06/2016] [Indexed: 02/06/2023]
Abstract
Uncovering genomic regions involved in adaption is a major goal in evolutionary biology. High-throughput sequencing now makes it possible to tackle this challenge in nonmodel species. Yet, despite the increasing number of methods targeted to specifically detect genomic footprints of selection, the complex demography of natural populations often causes high rates of false positive in gene discoveries. The aim of this study was to identify climate adaptations in wild pearl millet populations, Cenchrus americanus ssp. monodii. We focused on two climate gradients, one in Mali and one in Niger. We used a two-step strategy to limit false-positive outliers. First, we considered gradients as biological replicates and performed RNA sequencing of four populations at the extremities. We combined four methods-three based on differentiation among populations and one based on diversity patterns within populations-to identify outlier SNPs from a set of 87 218 high-quality SNPs. Among 11 155 contigs of pearl millet reference transcriptome, 540 exhibited selection signals as evidenced by at least one of the four methods. In a second step, we genotyped 762 samples in 11 additional populations distributed along the gradients using SNPs from the detected contigs and random SNPs as control. We further assessed selection on this large data set using a differentiation-based method and a method based on correlations with environmental variables based. Four contigs displayed consistent signatures between the four extreme and 11 additional populations, two of which were linked to abiotic and biotic stress responses.
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Affiliation(s)
- Cécile Berthouly-Salazar
- Institut de Recherche pour le Développement (IRD), UMR Diversité, Adaptation et Développement des Plantes (DIADE), 34394, Montpellier Cedex 5, France. .,LMI LAPSE, Campus de Bel Air, route des Hydrocarbures, Dakar, Senegal.
| | - Anne-Céline Thuillet
- Institut de Recherche pour le Développement (IRD), UMR Diversité, Adaptation et Développement des Plantes (DIADE), 34394, Montpellier Cedex 5, France
| | - Bénédicte Rhoné
- Institut de Recherche pour le Développement (IRD), UMR Diversité, Adaptation et Développement des Plantes (DIADE), 34394, Montpellier Cedex 5, France.,Université Lyon 1, CNRS, UMR5558, Laboratoire de Biométrie et Biologie Evolutive, F-69622, Villeurbanne, France
| | - Cédric Mariac
- Institut de Recherche pour le Développement (IRD), UMR Diversité, Adaptation et Développement des Plantes (DIADE), 34394, Montpellier Cedex 5, France
| | - Issaka Salia Ousseini
- Institut de Recherche pour le Développement (IRD), UMR Diversité, Adaptation et Développement des Plantes (DIADE), 34394, Montpellier Cedex 5, France
| | - Marie Couderc
- Institut de Recherche pour le Développement (IRD), UMR Diversité, Adaptation et Développement des Plantes (DIADE), 34394, Montpellier Cedex 5, France
| | - Maud I Tenaillon
- Génétique Quantitative et Evolution - Le Moulon, INRA - Université Paris-Sud - CNRS - AgroParisTech, Université Paris-Saclay, Ferme du Moulon, 91190, Gif-sur-Yvette, France
| | - Yves Vigouroux
- Institut de Recherche pour le Développement (IRD), UMR Diversité, Adaptation et Développement des Plantes (DIADE), 34394, Montpellier Cedex 5, France
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139
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Davis GA, Kanazawa A, Schöttler MA, Kohzuma K, Froehlich JE, Rutherford AW, Satoh-Cruz M, Minhas D, Tietz S, Dhingra A, Kramer DM. Limitations to photosynthesis by proton motive force-induced photosystem II photodamage. eLife 2016. [PMID: 27697149 DOI: 10.7554/elife.16921.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023] Open
Abstract
The thylakoid proton motive force (pmf) generated during photosynthesis is the essential driving force for ATP production; it is also a central regulator of light capture and electron transfer. We investigated the effects of elevated pmf on photosynthesis in a library of Arabidopsis thaliana mutants with altered rates of thylakoid lumen proton efflux, leading to a range of steady-state pmf extents. We observed the expected pmf-dependent alterations in photosynthetic regulation, but also strong effects on the rate of photosystem II (PSII) photodamage. Detailed analyses indicate this effect is related to an elevated electric field (Δψ) component of the pmf, rather than lumen acidification, which in vivo increased PSII charge recombination rates, producing singlet oxygen and subsequent photodamage. The effects are seen even in wild type plants, especially under fluctuating illumination, suggesting that Δψ-induced photodamage represents a previously unrecognized limiting factor for plant productivity under dynamic environmental conditions seen in the field.
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Affiliation(s)
- Geoffry A Davis
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
- Graduate Program of Cell and Molecular Biology, Michigan State University, East Lansing, United States
| | - Atsuko Kanazawa
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
- Department of Chemistry, Michigan State University, East Lansing, United States
| | | | - Kaori Kohzuma
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | - John E Froehlich
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | | | - Mio Satoh-Cruz
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | - Deepika Minhas
- Department of Horticulture, Washington State University, Pullman, United States
| | - Stefanie Tietz
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | - Amit Dhingra
- Department of Horticulture, Washington State University, Pullman, United States
| | - David M Kramer
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, United States
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140
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Davis GA, Kanazawa A, Schöttler MA, Kohzuma K, Froehlich JE, Rutherford AW, Satoh-Cruz M, Minhas D, Tietz S, Dhingra A, Kramer DM. Limitations to photosynthesis by proton motive force-induced photosystem II photodamage. eLife 2016; 5. [PMID: 27697149 PMCID: PMC5050024 DOI: 10.7554/elife.16921] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 09/08/2016] [Indexed: 12/20/2022] Open
Abstract
The thylakoid proton motive force (pmf) generated during photosynthesis is the essential driving force for ATP production; it is also a central regulator of light capture and electron transfer. We investigated the effects of elevated pmf on photosynthesis in a library of Arabidopsis thaliana mutants with altered rates of thylakoid lumen proton efflux, leading to a range of steady-state pmf extents. We observed the expected pmf-dependent alterations in photosynthetic regulation, but also strong effects on the rate of photosystem II (PSII) photodamage. Detailed analyses indicate this effect is related to an elevated electric field (Δψ) component of the pmf, rather than lumen acidification, which in vivo increased PSII charge recombination rates, producing singlet oxygen and subsequent photodamage. The effects are seen even in wild type plants, especially under fluctuating illumination, suggesting that Δψ-induced photodamage represents a previously unrecognized limiting factor for plant productivity under dynamic environmental conditions seen in the field. DOI:http://dx.doi.org/10.7554/eLife.16921.001
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Affiliation(s)
- Geoffry A Davis
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States.,Graduate Program of Cell and Molecular Biology, Michigan State University, East Lansing, United States
| | - Atsuko Kanazawa
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States.,Department of Chemistry, Michigan State University, East Lansing, United States
| | | | - Kaori Kohzuma
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | - John E Froehlich
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | | | - Mio Satoh-Cruz
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | - Deepika Minhas
- Department of Horticulture, Washington State University, Pullman, United States
| | - Stefanie Tietz
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States
| | - Amit Dhingra
- Department of Horticulture, Washington State University, Pullman, United States
| | - David M Kramer
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, United States.,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, United States
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141
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Duan Z, Kong F, Zhang L, Li W, Zhang J, Peng L. A bestrophin-like protein modulates the proton motive force across the thylakoid membrane in Arabidopsis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2016; 58:848-858. [PMID: 26947269 PMCID: PMC5074266 DOI: 10.1111/jipb.12475] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 03/03/2016] [Indexed: 05/20/2023]
Abstract
During photosynthesis, photosynthetic electron transport generates a proton motive force (pmf) across the thylakoid membrane, which is used for ATP biosynthesis via ATP synthase in the chloroplast. The pmf is composed of an electric potential (ΔΨ) and an osmotic component (ΔpH). Partitioning between these components in chloroplasts is strictly regulated in response to fluctuating environments. However, our knowledge of the molecular mechanisms that regulate pmf partitioning is limited. Here, we report a bestrophin-like protein (AtBest), which is critical for pmf partitioning. While the ΔpH component was slightly reduced in atbest, the ΔΨ component was much greater in this mutant than in the wild type, resulting in less efficient activation of nonphotochemical quenching (NPQ) upon both illumination and a shift from low light to high light. Although no visible phenotype was observed in the atbest mutant in the greenhouse, this mutant exhibited stronger photoinhibition than the wild type when grown in the field. AtBest belongs to the bestrophin family proteins, which are believed to function as chloride (Cl- ) channels. Thus, our findings reveal an important Cl- channel required for ion transport and homeostasis across the thylakoid membrane in higher plants. These processes are essential for fine-tuning photosynthesis under fluctuating environmental conditions.
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Affiliation(s)
- Zhikun Duan
- Key Laboratory of Photobiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fanna Kong
- Key Laboratory of Photobiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lin Zhang
- Key Laboratory of Photobiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenjing Li
- Key Laboratory of Photobiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Jiao Zhang
- Key Laboratory of Photobiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Lianwei Peng
- Key Laboratory of Photobiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
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142
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Carmody M, Waszczak C, Idänheimo N, Saarinen T, Kangasjärvi J. ROS signalling in a destabilised world: A molecular understanding of climate change. JOURNAL OF PLANT PHYSIOLOGY 2016; 203:69-83. [PMID: 27364884 DOI: 10.1016/j.jplph.2016.06.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 06/13/2016] [Accepted: 06/14/2016] [Indexed: 05/29/2023]
Abstract
Climate change results in increased intensity and frequency of extreme abiotic and biotic stress events. In plants, reactive oxygen species (ROS) accumulate in proportion to the level of stress and are major signalling and regulatory metabolites coordinating growth, defence, acclimation and cell death. Our knowledge of ROS homeostasis, sensing, and signalling is therefore key to understanding the impacts of climate change at the molecular level. Current research is uncovering new insights into temporal-spatial, cell-to-cell and systemic ROS signalling pathways, particularly how these affect plant growth, defence, and more recently acclimation mechanisms behind stress priming and long term stress memory. Understanding the stabilising and destabilising factors of ROS homeostasis and signalling in plants exposed to extreme and fluctuating stress will concomitantly reveal how to address future climate change challenges in global food security and biodiversity management.
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Affiliation(s)
- Melanie Carmody
- Division of Plant Biology, Viikki Plant Science Centre, Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland.
| | - Cezary Waszczak
- Division of Plant Biology, Viikki Plant Science Centre, Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland.
| | - Niina Idänheimo
- Division of Plant Biology, Viikki Plant Science Centre, Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland.
| | - Timo Saarinen
- Division of Plant Biology, Viikki Plant Science Centre, Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland.
| | - Jaakko Kangasjärvi
- Division of Plant Biology, Viikki Plant Science Centre, Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland; Distinguished Scientist Fellowship Program, College of Science, King Saud University, Riyadh, Saudi Arabia.
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143
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Aranda-Sicilia MN, Aboukila A, Armbruster U, Cagnac O, Schumann T, Kunz HH, Jahns P, Rodríguez-Rosales MP, Sze H, Venema K. Envelope K+/H+ Antiporters AtKEA1 and AtKEA2 Function in Plastid Development. PLANT PHYSIOLOGY 2016; 172:441-9. [PMID: 27443603 PMCID: PMC5074627 DOI: 10.1104/pp.16.00995] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 07/19/2016] [Indexed: 05/04/2023]
Abstract
It is well established that thylakoid membranes of chloroplasts convert light energy into chemical energy, yet the development of chloroplast and thylakoid membranes is poorly understood. Loss of function of the two envelope K(+)/H(+) antiporters AtKEA1 and AtKEA2 was shown previously to have negative effects on the efficiency of photosynthesis and plant growth; however, the molecular basis remained unclear. Here, we tested whether the previously described phenotypes of double mutant kea1kea2 plants are due in part to defects during early chloroplast development in Arabidopsis (Arabidopsis thaliana). We show that impaired growth and pigmentation is particularly evident in young expanding leaves of kea1kea2 mutants. In proliferating leaf zones, chloroplasts contain much lower amounts of photosynthetic complexes and chlorophyll. Strikingly, AtKEA1 and AtKEA2 proteins accumulate to high amounts in small and dividing plastids, where they are specifically localized to the two caps of the organelle separated by the fission plane. The unusually long amino-terminal domain of 550 residues that precedes the antiport domain appears to tether the full-length AtKEA2 protein to the two caps. Finally, we show that the double mutant contains 30% fewer chloroplasts per cell. Together, these results show that AtKEA1 and AtKEA2 transporters in specific microdomains of the inner envelope link local osmotic, ionic, and pH homeostasis to plastid division and thylakoid membrane formation.
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Affiliation(s)
- María Nieves Aranda-Sicilia
- Departimento de Bioquímica, Biología Celular, y Molecular de Plantas, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain (M.N.A.-S., A.A., O.C., M.P.R.-R., K.V.);Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, California 94720 (U.A.);Institute of Plant Biochemistry, Heinrich-Heine-University Düsseldorf, D-40225 Duesseldorf, Germany (T.S., P.J.);School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236 (H.-H.K.); andDepartment of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742 (H.S.)
| | - Ali Aboukila
- Departimento de Bioquímica, Biología Celular, y Molecular de Plantas, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain (M.N.A.-S., A.A., O.C., M.P.R.-R., K.V.);Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, California 94720 (U.A.);Institute of Plant Biochemistry, Heinrich-Heine-University Düsseldorf, D-40225 Duesseldorf, Germany (T.S., P.J.);School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236 (H.-H.K.); andDepartment of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742 (H.S.)
| | - Ute Armbruster
- Departimento de Bioquímica, Biología Celular, y Molecular de Plantas, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain (M.N.A.-S., A.A., O.C., M.P.R.-R., K.V.);Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, California 94720 (U.A.);Institute of Plant Biochemistry, Heinrich-Heine-University Düsseldorf, D-40225 Duesseldorf, Germany (T.S., P.J.);School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236 (H.-H.K.); andDepartment of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742 (H.S.)
| | - Olivier Cagnac
- Departimento de Bioquímica, Biología Celular, y Molecular de Plantas, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain (M.N.A.-S., A.A., O.C., M.P.R.-R., K.V.);Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, California 94720 (U.A.);Institute of Plant Biochemistry, Heinrich-Heine-University Düsseldorf, D-40225 Duesseldorf, Germany (T.S., P.J.);School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236 (H.-H.K.); andDepartment of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742 (H.S.)
| | - Tobias Schumann
- Departimento de Bioquímica, Biología Celular, y Molecular de Plantas, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain (M.N.A.-S., A.A., O.C., M.P.R.-R., K.V.);Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, California 94720 (U.A.);Institute of Plant Biochemistry, Heinrich-Heine-University Düsseldorf, D-40225 Duesseldorf, Germany (T.S., P.J.);School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236 (H.-H.K.); andDepartment of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742 (H.S.)
| | - Hans-Henning Kunz
- Departimento de Bioquímica, Biología Celular, y Molecular de Plantas, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain (M.N.A.-S., A.A., O.C., M.P.R.-R., K.V.);Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, California 94720 (U.A.);Institute of Plant Biochemistry, Heinrich-Heine-University Düsseldorf, D-40225 Duesseldorf, Germany (T.S., P.J.);School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236 (H.-H.K.); andDepartment of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742 (H.S.)
| | - Peter Jahns
- Departimento de Bioquímica, Biología Celular, y Molecular de Plantas, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain (M.N.A.-S., A.A., O.C., M.P.R.-R., K.V.);Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, California 94720 (U.A.);Institute of Plant Biochemistry, Heinrich-Heine-University Düsseldorf, D-40225 Duesseldorf, Germany (T.S., P.J.);School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236 (H.-H.K.); andDepartment of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742 (H.S.)
| | - María Pilar Rodríguez-Rosales
- Departimento de Bioquímica, Biología Celular, y Molecular de Plantas, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain (M.N.A.-S., A.A., O.C., M.P.R.-R., K.V.);Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, California 94720 (U.A.);Institute of Plant Biochemistry, Heinrich-Heine-University Düsseldorf, D-40225 Duesseldorf, Germany (T.S., P.J.);School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236 (H.-H.K.); andDepartment of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742 (H.S.)
| | - Heven Sze
- Departimento de Bioquímica, Biología Celular, y Molecular de Plantas, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain (M.N.A.-S., A.A., O.C., M.P.R.-R., K.V.);Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, California 94720 (U.A.);Institute of Plant Biochemistry, Heinrich-Heine-University Düsseldorf, D-40225 Duesseldorf, Germany (T.S., P.J.);School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236 (H.-H.K.); andDepartment of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742 (H.S.)
| | - Kees Venema
- Departimento de Bioquímica, Biología Celular, y Molecular de Plantas, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain (M.N.A.-S., A.A., O.C., M.P.R.-R., K.V.);Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, California 94720 (U.A.);Institute of Plant Biochemistry, Heinrich-Heine-University Düsseldorf, D-40225 Duesseldorf, Germany (T.S., P.J.);School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236 (H.-H.K.); andDepartment of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742 (H.S.)
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144
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Rapid hyperosmotic-induced Ca2+ responses in Arabidopsis thaliana exhibit sensory potentiation and involvement of plastidial KEA transporters. Proc Natl Acad Sci U S A 2016; 113:E5242-9. [PMID: 27528686 DOI: 10.1073/pnas.1519555113] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Plants experience hyperosmotic stress when faced with saline soils and possibly with drought stress, but it is currently unclear how plant roots perceive this stress in an environment of dynamic water availabilities. Hyperosmotic stress induces a rapid rise in intracellular Ca(2+) concentrations ([Ca(2+)]i) in plants, and this Ca(2+) response may reflect the activities of osmo-sensory components. Here, we find in the reference plant Arabidopsis thaliana that the rapid hyperosmotic-induced Ca(2+) response exhibited enhanced response magnitudes after preexposure to an intermediate hyperosmotic stress. We term this phenomenon "osmo-sensory potentiation." The initial sensing and potentiation occurred in intact plants as well as in roots. Having established a quantitative understanding of wild-type responses, we investigated effects of pharmacological inhibitors and candidate channel/transporter mutants. Quintuple mechano-sensitive channels of small conductance-like (MSL) plasma membrane-targeted channel mutants as well as double mid1-complementing activity (MCA) channel mutants did not affect the response. Interestingly, however, double mutations in the plastid K(+) exchange antiporter (KEA) transporters kea1kea2 and a single mutation that does not visibly affect chloroplast structure, kea3, impaired the rapid hyperosmotic-induced Ca(2+) responses. These mutations did not significantly affect sensory potentiation of the response. These findings suggest that plastids may play an important role in early steps mediating the response to hyperosmotic stimuli. Together, these findings demonstrate that the plant osmo-sensory components necessary to generate rapid osmotic-induced Ca(2+) responses remain responsive under varying osmolarities, endowing plants with the ability to perceive the dynamic intensities of water limitation imposed by osmotic stress.
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145
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Kaiser E, Morales A, Harbinson J, Heuvelink E, Prinzenberg AE, Marcelis LFM. Metabolic and diffusional limitations of photosynthesis in fluctuating irradiance in Arabidopsis thaliana. Sci Rep 2016; 6:31252. [PMID: 27502328 PMCID: PMC4977489 DOI: 10.1038/srep31252] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/11/2016] [Indexed: 11/09/2022] Open
Abstract
A better understanding of the metabolic and diffusional limitations of photosynthesis in fluctuating irradiance can help identify targets for improving crop yields. We used different genotypes of Arabidopsis thaliana to characterise the importance of Rubisco activase (Rca), stomatal conductance (gs), non-photochemical quenching of chlorophyll fluorescence (NPQ) and sucrose phosphate synthase (SPS) on photosynthesis in fluctuating irradiance. Leaf gas exchange and chlorophyll fluorescence were measured in leaves exposed to stepwise increases and decreases in irradiance. rwt43, which has a constitutively active Rubisco enzyme in different irradiance intensities (except in darkness), showed faster increases than the wildtype, Colombia-0, in photosynthesis rates after step increases in irradiance. rca-2, having decreased Rca concentration, showed lower rates of increase. In aba2-1, high gs increased the rate of change after stepwise irradiance increases, while in C24, low gs tended to decrease it. Differences in rates of change between Colombia-0 and plants with low levels of NPQ (npq1-2, npq4-1) or SPS (spsa1) were negligible. In Colombia-0, the regulation of Rubisco activation and of gs were therefore limiting for photosynthesis in fluctuating irradiance, while levels of NPQ or SPS were not. This suggests Rca and gs as targets for improvement of photosynthesis of plants in fluctuating irradiance.
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Affiliation(s)
- Elias Kaiser
- Horticulture and Product Physiology Group, Department of Plant Sciences, Wageningen University, PO Box 16, 6700 AA Wageningen, The Netherlands
| | - Alejandro Morales
- Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University, PO Box 430, 6700 AK Wageningen, The Netherlands
| | - Jeremy Harbinson
- Horticulture and Product Physiology Group, Department of Plant Sciences, Wageningen University, PO Box 16, 6700 AA Wageningen, The Netherlands
| | - Ep Heuvelink
- Horticulture and Product Physiology Group, Department of Plant Sciences, Wageningen University, PO Box 16, 6700 AA Wageningen, The Netherlands
| | - Aina E Prinzenberg
- Horticulture and Product Physiology Group, Department of Plant Sciences, Wageningen University, PO Box 16, 6700 AA Wageningen, The Netherlands.,Laboratory of Genetics, Department of Plant Sciences, Wageningen University, PO Box 16, 6700 AA Wageningen, The Netherlands
| | - Leo F M Marcelis
- Horticulture and Product Physiology Group, Department of Plant Sciences, Wageningen University, PO Box 16, 6700 AA Wageningen, The Netherlands
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146
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Armbruster U, Leonelli L, Correa Galvis V, Strand D, Quinn EH, Jonikas MC, Niyogi KK. Regulation and Levels of the Thylakoid K+/H+ Antiporter KEA3 Shape the Dynamic Response of Photosynthesis in Fluctuating Light. PLANT & CELL PHYSIOLOGY 2016; 57:1557-1567. [PMID: 27335350 PMCID: PMC4937787 DOI: 10.1093/pcp/pcw085] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 04/24/2016] [Indexed: 05/22/2023]
Abstract
Crop canopies create environments of highly fluctuating light intensities. In such environments, photoprotective mechanisms and their relaxation kinetics have been hypothesized to limit photosynthetic efficiency and therefore crop yield potential. Here, we show that overexpression of the Arabidopsis thylakoid K+/H+ antiporter KEA3 accelerates the relaxation of photoprotective energy-dependent quenching after transitions from high to low light in Arabidopsis and tobacco. This, in turn, enhances PSII quantum efficiency in both organisms, supporting that in wild-type plants, residual light energy quenching following a high to low light transition represents a limitation to photosynthetic efficiency in fluctuating light. This finding underscores the potential of accelerating quenching relaxation as a building block for improving photosynthetic efficiency in the field. Additionally, by overexpressing natural KEA3 variants with modification to the C-terminus, we show that KEA3 activity is regulated by a mechanism involving its lumen-localized C-terminus, which lowers KEA3 activity in high light. This regulatory mechanism fine-tunes the balance between photoprotective energy dissipation in high light and maximum quantum yield in low light, likely to be critical for efficient photosynthesis in fluctuating light conditions.
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Affiliation(s)
- Ute Armbruster
- Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
- Carnegie Institution for Science, Department of Plant Biology, Stanford, CA 94305, USA
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Lauriebeth Leonelli
- Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Viviana Correa Galvis
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Deserah Strand
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Erica H Quinn
- Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Martin C Jonikas
- Carnegie Institution for Science, Department of Plant Biology, Stanford, CA 94305, USA
| | - Krishna K Niyogi
- Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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147
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Herdean A, Teardo E, Nilsson AK, Pfeil BE, Johansson ON, Ünnep R, Nagy G, Zsiros O, Dana S, Solymosi K, Garab G, Szabó I, Spetea C, Lundin B. A voltage-dependent chloride channel fine-tunes photosynthesis in plants. Nat Commun 2016; 7:11654. [PMID: 27216227 PMCID: PMC4890181 DOI: 10.1038/ncomms11654] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 04/16/2016] [Indexed: 11/17/2022] Open
Abstract
In natural habitats, plants frequently experience rapid changes in the intensity of sunlight. To cope with these changes and maximize growth, plants adjust photosynthetic light utilization in electron transport and photoprotective mechanisms. This involves a proton motive force (PMF) across the thylakoid membrane, postulated to be affected by unknown anion (Cl(-)) channels. Here we report that a bestrophin-like protein from Arabidopsis thaliana functions as a voltage-dependent Cl(-) channel in electrophysiological experiments. AtVCCN1 localizes to the thylakoid membrane, and fine-tunes PMF by anion influx into the lumen during illumination, adjusting electron transport and the photoprotective mechanisms. The activity of AtVCCN1 accelerates the activation of photoprotective mechanisms on sudden shifts to high light. Our results reveal that AtVCCN1, a member of a conserved anion channel family, acts as an early component in the rapid adjustment of photosynthesis in variable light environments.
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Affiliation(s)
- Andrei Herdean
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Enrico Teardo
- Department of Biology, University of Padova, Padova 35121, Italy
| | - Anders K. Nilsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Bernard E. Pfeil
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Oskar N. Johansson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Renáta Ünnep
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen 5232, Switzerland
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest 1121, Hungary
| | - Gergely Nagy
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen 5232, Switzerland
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest 1121, Hungary
| | - Ottó Zsiros
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged 6701, Hungary
| | - Somnath Dana
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Katalin Solymosi
- Department of Plant Anatomy, Eötvös Loránd University, Budapest 1117, Hungary
| | - Győző Garab
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged 6701, Hungary
| | - Ildikó Szabó
- Department of Biology, University of Padova, Padova 35121, Italy
- CNR Neuroscience Institute, Padova 35121, Italy
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Björn Lundin
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
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148
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Zhou H, Qi K, Liu X, Yin H, Wang P, Chen J, Wu J, Zhang S. Genome-wide identification and comparative analysis of the cation proton antiporters family in pear and four other Rosaceae species. Mol Genet Genomics 2016; 291:1727-42. [DOI: 10.1007/s00438-016-1215-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 05/06/2016] [Indexed: 11/28/2022]
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149
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Czerny DD, Padmanaban S, Anishkin A, Venema K, Riaz Z, Sze H. Protein architecture and core residues in unwound α-helices provide insights to the transport function of plant AtCHX17. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1983-1998. [PMID: 27179641 DOI: 10.1016/j.bbamem.2016.05.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/13/2016] [Accepted: 05/08/2016] [Indexed: 01/27/2023]
Abstract
Using Arabidopsis thaliana AtCHX17 as an example, we combine structural modeling and mutagenesis to provide insights on its protein architecture and transport function which is poorly characterized. This approach is based on the observation that protein structures are significantly more conserved in evolution than linear sequences, and mechanistic similarities among diverse transporters are emerging. Two homology models of AtCHX17 were obtained that show a protein fold similar to known structures of bacterial Na(+)/H(+) antiporters, EcNhaA and TtNapA. The distinct secondary and tertiary structure models highlighted residues at positions potentially important for CHX17 activity. Mutagenesis showed that asparagine-N200 and aspartate-D201 inside transmembrane5 (TM5), and lysine-K355 inside TM10 are critical for AtCHX17 activity. We reveal previously unrecognized threonine-T170 and lysine-K383 as key residues at unwound regions in the middle of TM4 and TM11 α-helices, respectively. Mutation of glutamate-E111 located near the membrane surface inhibited AtCHX17 activity, suggesting a role in pH sensing. The long carboxylic tail of unknown purpose has an alternating β-sheet and α-helix secondary structure that is conserved in prokaryote universal stress proteins. These results support the overall architecture of AtCHX17 and identify D201, N200 and novel residues T170 and K383 at the functional core which likely participates in ion recognition, coordination and/or translocation, similar to characterized cation/H(+) exchangers. The core of AtCHX17 models according to EcNhaA and TtNapA templates faces inward and outward, respectively, which may reflect two conformational states of the alternating access transport mode for proteins belonging to the plant CHX family.
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Affiliation(s)
- Daniel D Czerny
- Department of Cell Biology and Molecular Genetics (DC, SP, ZR, HS), University of Maryland, College Park, MD 20742, USA
| | - Senthilkumar Padmanaban
- Department of Cell Biology and Molecular Genetics (DC, SP, ZR, HS), University of Maryland, College Park, MD 20742, USA
| | - Andriy Anishkin
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Kees Venema
- Dpto de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, c/. Profesor Albareda 1, 18008Granada, Spain
| | - Zoya Riaz
- Department of Cell Biology and Molecular Genetics (DC, SP, ZR, HS), University of Maryland, College Park, MD 20742, USA
| | - Heven Sze
- Department of Cell Biology and Molecular Genetics (DC, SP, ZR, HS), University of Maryland, College Park, MD 20742, USA; Maryland Agricultural Experiment Station, Department of Plant Science and Landscape Architecture (HS), University of Maryland, College Park, MD 20742, USA.
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150
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Abstract
Jonikas’ career jumps have advanced Chlamydomonas systems biology.
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