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Huang W, Suorsa M, Zhang SB. In vivo regulation of thylakoid proton motive force in immature leaves. PHOTOSYNTHESIS RESEARCH 2018; 138:207-218. [PMID: 30056561 DOI: 10.1007/s11120-018-0565-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 07/24/2018] [Indexed: 06/08/2023]
Abstract
In chloroplast, proton motive force (pmf) is critical for ATP synthesis and photoprotection. To prevent photoinhibition of photosynthetic apparatus, proton gradient (ΔpH) across the thylakoid membranes needs to be built up to minimize the production of reactive oxygen species (ROS) in thylakoid membranes. However, the regulation of thylakoid pmf in immature leaves is little known. In this study, we compared photosynthetic electron sinks, P700 redox state, non-photochemical quenching (NPQ), and electrochromic shift (ECS) signal in immature and mature leaves of a cultivar of Camellia. The immature leaves displayed lower linear electron flow and cyclic electron flow, but higher levels of NPQ and P700 oxidation ratio under high light. Meanwhile, we found that pmf and ΔpH were higher in the immature leaves. Furthermore, the immature leaves showed significantly lower thylakoid proton conductivity than mature leaves. These results strongly indicated that immature leaves can build up enough ΔpH by modulating proton efflux from the lumenal side to the stromal side of thylakoid membranes, which is essential to prevent photoinhibition via thermal energy dissipation and photosynthetic control of electron transfer. This study highlights that the activity of chloroplast ATP synthase is a key safety valve for photoprotection in immature leaves.
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Affiliation(s)
- Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China.
| | | | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
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52
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Huang W, Tikkanen M, Cai YF, Wang JH, Zhang SB. Chloroplastic ATP synthase optimizes the trade-off between photosynthetic CO2 assimilation and photoprotection during leaf maturation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:1067-1074. [DOI: 10.1016/j.bbabio.2018.06.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/03/2018] [Accepted: 06/08/2018] [Indexed: 11/24/2022]
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Virlouvet L, Avenson TJ, Du Q, Zhang C, Liu N, Fromm M, Avramova Z, Russo SE. Dehydration Stress Memory: Gene Networks Linked to Physiological Responses During Repeated Stresses of Zea mays. FRONTIERS IN PLANT SCIENCE 2018; 9:1058. [PMID: 30087686 PMCID: PMC6066539 DOI: 10.3389/fpls.2018.01058] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 06/28/2018] [Indexed: 05/19/2023]
Abstract
Stress memory refers to the observation that an initial, sub-lethal stress alters plants' responses to subsequent stresses. Previous transcriptome analyses of maize seedlings exposed to a repeated dehydration stress has revealed the existence of transcriptional stress memory in Zea mays. Whether drought-related physiological responses also display memory and how transcriptional memory translates into physiological memory are fundamental questions that are still unanswered. Using a systems-biology approach we investigate whether/how transcription memory responses established in the genome-wide analysis of Z. mays correlate with 14 physiological parameters measured during a repeated exposure of maize seedlings to dehydration stress. Co-expression network analysis revealed ten gene modules correlating strongly with particular physiological processes, and one module displaying strong, yet divergent, correlations with several processes suggesting involvement of these genes in coordinated responses across networks. Two processes key to the drought response, stomatal conductance and non-photochemical quenching, displayed contrasting memory patterns that may reflect trade-offs related to metabolic costs versus benefits of cellular protection. The main contribution of this study is the demonstration of coordinated changes in transcription memory responses at the genome level and integrated physiological responses at the cellular level upon repetitive stress exposures. The results obtained by the network-based systems analysis challenge the commonly held view that short-term physiological responses to stress are primarily mediated biochemically.
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Affiliation(s)
- Laetitia Virlouvet
- Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE, United States
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | | | - Qian Du
- School of Biological Sciences, University of Nebraska, Lincoln, NE, United States
| | - Chi Zhang
- School of Biological Sciences, University of Nebraska, Lincoln, NE, United States
| | - Ning Liu
- Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE, United States
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Michael Fromm
- Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE, United States
| | - Zoya Avramova
- School of Biological Sciences, University of Nebraska, Lincoln, NE, United States
| | - Sabrina E. Russo
- School of Biological Sciences, University of Nebraska, Lincoln, NE, United States
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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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55
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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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Huang W, Zhang SB, Liu T. Moderate Photoinhibition of Photosystem II Significantly Affects Linear Electron Flow in the Shade-Demanding Plant Panax notoginseng. FRONTIERS IN PLANT SCIENCE 2018; 9:637. [PMID: 29868090 PMCID: PMC5962726 DOI: 10.3389/fpls.2018.00637] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 04/25/2018] [Indexed: 05/17/2023]
Abstract
Although photoinhibition of photosystem II (PSII) frequently occurs under natural growing conditions, knowledge about the effect of moderate photoinhibition on linear electron flow (LEF) remains controversial. Furthermore, mechanisms underlying the decrease in LEF upon PSII photoinhibition are not well clarified. We examined how selective PSII photoinhibition influenced LEF in the attached leaves of shade-demanding plant Panax notoginseng. After leaves were exposed to a high level of light (2258 μmol photons m-2 s-1) for 30 and 60 min, the maximum quantum yield of PSII (Fv/Fm) decreased by 17 and 23%, respectively, whereas the maximum photo-oxidizable P700 (Pm) remained stable. Therefore, this species displayed selective PSII photodamage under strong illumination. After these treatments, LEF was significantly decreased under all light levels but acidification of the thylakoid lumen changed only slightly. Furthermore, the decrease in LEF under low light was positively correlated with the extent of PSII photoinhibition. Thus, the decline in LEF was not caused by the enhancement of lumenal acidification, but was induced by a decrease in PSII activity. These results indicate that residual PSII activity is an important determinant of LEF in this shade-adapted species, and they provide new insight into how strong illumination affects the growth of shade-demanding plants.
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Affiliation(s)
- Wei Huang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Shi-Bao Zhang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Tao Liu
- National Local Joint Engineering Research Center on Germplasm Utilization and Innovation of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, Kunming, China
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57
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Shimakawa G, Shaku K, Miyake C. Reduction-Induced Suppression of Electron Flow (RISE) Is Relieved by Non-ATP-Consuming Electron Flow in Synechococcus elongatus PCC 7942. Front Microbiol 2018; 9:886. [PMID: 29867800 PMCID: PMC5949335 DOI: 10.3389/fmicb.2018.00886] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 04/18/2018] [Indexed: 01/13/2023] Open
Abstract
Photosynthetic organisms oxidize P700 to suppress the production of reactive oxygen species (ROS) in photosystem I (PSI) in response to the lower efficiency of photosynthesis under high light and low CO2 conditions. Previously, we found a positive relationship between reduction of plastoquinone (PQ) pool and oxidation of P700, which we named reduction-induced suppression of electron flow (RISE). In the RISE model, we proposed that the highly reduced state of the PQ pool suppresses Q-cycle turnover to oxidize P700 in PSI. Here, we tested whether RISE was relieved by the oxidation of the PQ pool, but not by the dissipation of the proton gradient (ΔpH) across the thylakoid membrane. Formation of ΔpH can also suppress electron flow to P700, because acidification on the luminal side of the thylakoid membrane lowers oxidation of reduced PQ in the cytochrome b6/f complex. We drove photosynthetic electron transport using H2O2-scavenging peroxidase reactions. Peroxidase reduces H2O2 with electron donors regenerated along the photosynthetic electron transport system, thereby promoting the formation of ΔpH. Addition of H2O2 to the cyanobacterium Synechococcus elongatus PCC 7942 under low CO2 conditions induced photochemical quenching of chlorophyll fluorescence, enhanced NADPH fluorescence and reduced P700. Thus, peroxidase reactions relieved the RISE mechanism, indicating that P700 oxidation can be induced only by the reduction of PQ to suppress the production of ROS in PSI. Overall, our data suggest that RISE regulates the redox state of P700 in PSI in cooperation with ΔpH regulation.
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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
| | - Keiichiro Shaku
- 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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58
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Huang W, Yang YJ, Zhang SB, Liu T. Cyclic Electron Flow around Photosystem I Promotes ATP Synthesis Possibly Helping the Rapid Repair of Photodamaged Photosystem II at Low Light. FRONTIERS IN PLANT SCIENCE 2018; 9:239. [PMID: 29535751 PMCID: PMC5834426 DOI: 10.3389/fpls.2018.00239] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 02/09/2018] [Indexed: 05/03/2023]
Abstract
In higher plants, moderate photoinhibition of photosystem II (PSII) leads to a stimulation of cyclic electron flow (CEF) at low light, which is accompanied by an increase in the P700 oxidation ratio. However, the specific role of CEF stimulation at low light is not well known. Furthermore, the mechanism underlying this increase in P700 oxidation ratio at low light is unclear. To address these questions, intact leaves of the shade-adapted plant Panax notoginseng were treated at 2258 μmol photons m-2 s-1 for 30 min to induce PSII photoinhibition. Before and after this high-light treatment, PSI and PSII activity, the energy quenching in PSII, the redox state of PSI and proton motive force (pmf) at a low light of 54 μmol photons m-2 s-1 were determined at the steady state. After high-light treatment, electron flow through PSII (ETRII) significantly decreased but CEF was remarkably stimulated. The P700 oxidation ratio significantly increased but non-photochemical quenching changed negligibly. Concomitantly, the total pmf decreased significantly and the proton gradient (ΔpH) across the thylakoid membrane remained stable. Furthermore, the P700 oxidation ratio was negatively correlated with the value of ETRII. These results suggest that upon PSII photoinhibition, CEF is stimulated to increase the ATP synthesis, facilitating the rapid repair of photodamaged PSII. The increase in P700 oxidation ratio at low light cannot be explained by the change in pmf, but is primarily controlled by electron transfer from PSII.
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Affiliation(s)
- Wei Huang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Ying-Jie Yang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Shi-Bao Zhang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Tao Liu
- National-Local Joint Engineering Research Center on Germplasm Utilization and Innovation of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, Kunming, China
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59
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Da Q, Sun T, Wang M, Jin H, Li M, Feng D, Wang J, Wang HB, Liu B. M-type thioredoxins are involved in the xanthophyll cycle and proton motive force to alter NPQ under low-light conditions in Arabidopsis. PLANT CELL REPORTS 2018; 37:279-291. [PMID: 29080907 DOI: 10.1007/s00299-017-2229-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 10/18/2017] [Indexed: 06/07/2023]
Abstract
M-type thioredoxins are required to regulate zeaxanthin epoxidase activity and to maintain the steady-state level of the proton motive force, thereby influencing NPQ properties under low-light conditions in Arabidopsis. Non-photochemical quenching (NPQ) helps protect photosynthetic organisms from photooxidative damage via the non-radiative dissipation of energy as heat. Energy-dependent quenching (qE) is a major constituent of NPQ. However, the mechanism underlying the regulation of qE is not well understood. In this study, we demonstrate that the m-type thioredoxins TRX-m1, TRX-m2, and TRX-m4 (TRX-ms) interact with the xanthophyll cycle enzyme zeaxanthin epoxidase (ZE) and are required for maintaining the redox-dependent stabilization of ZE by regulating its intermolecular disulfide bridges. Reduced ZE activity and accumulated zeaxanthin levels were observed under TRX-ms deficiency. Furthermore, concurrent deficiency of TRX-ms resulted in a significant increase in proton motive force (pmf) and acidification of the thylakoid lumen under low irradiance, perhaps due to the significantly reduced ATP synthase activity under TRX-ms deficiency. The increased pmf, combined with acidification of the thylakoid lumen and the accumulation of zeaxanthin, ultimately contribute to the elevated stable qE in VIGS-TRX-m2m4/m1 plants under low-light conditions. Taken together, these results indicate that TRX-ms are involved in regulating NPQ-dependent photoprotection in Arabidopsis.
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Affiliation(s)
- Qingen Da
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Ting Sun
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Menglong Wang
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Honglei Jin
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Mengshu Li
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Dongru Feng
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Jinfa Wang
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Hong-Bin Wang
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Bing Liu
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China.
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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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61
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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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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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63
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Abramson BW, Kachel B, Kramer DM, Ducat DC. Increased Photochemical Efficiency in Cyanobacteria via an Engineered Sucrose Sink. PLANT & CELL PHYSIOLOGY 2016; 57:2451-2460. [PMID: 27742883 DOI: 10.1093/pcp/pcw169] [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: 08/12/2016] [Accepted: 09/25/2016] [Indexed: 06/06/2023]
Abstract
In plants, a limited capacity to utilize or export the end-products of the Calvin-Benson cycle (CB) from photosynthetically active source cells to non-photosynthetic sink cells can result in reduced carbon capture and photosynthetic electron transport (PET), and lowered photochemical efficiency. The down-regulation of photosynthesis caused by reduced capacity to utilize photosynthate has been termed 'sink limitation'. Recently, several cyanobacterial and algal strains engineered to overproduce target metabolites have exhibited increased photochemistry, suggesting that possible source-sink regulatory mechanisms may be involved. We directly examined photochemical properties following induction of a heterologous sucrose 'sink' in the unicellular cyanobacterium Synechococcus elongatus PCC 7942. We show that total photochemistry increases proportionally to the experimentally controlled rate of sucrose export. Importantly, the quantum yield of PSII (ΦII) increases in response to sucrose export while the PET chain becomes more oxidized from less PSI acceptor-side limitation, suggesting increased CB activity and a decrease in sink limitation. Enhanced photosynthetic activity and linear electron flow are detectable within hours of induction of the heterologous sink and are independent of pigmentation alterations or the ionic/osmotic effects of the induction system. These observations provide direct evidence that secretion of heterologous carbon bioproducts can be used as an alternative approach to improve photosynthetic efficiency, presumably by by-passing sink limitation. Our results also suggest that engineered microalgal production strains are valuable alternative models for examining photosynthetic sink limitation because they enable greater control and monitoring of metabolite fluxes relative to plants.
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Affiliation(s)
- Bradley W Abramson
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
- Department of Cell and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Benjamin Kachel
- Department of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - David M Kramer
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Daniel C Ducat
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
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64
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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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65
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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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66
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Takagi D, Hashiguchi M, Sejima T, Makino A, Miyake C. Photorespiration provides the chance of cyclic electron flow to operate for the redox-regulation of P700 in photosynthetic electron transport system of sunflower leaves. PHOTOSYNTHESIS RESEARCH 2016; 129:279-90. [PMID: 27116126 DOI: 10.1007/s11120-016-0267-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 04/18/2016] [Indexed: 05/24/2023]
Abstract
To elucidate the molecular mechanism to oxidize the reaction center chlorophyll, P700, in PSI, we researched the effects of partial pressure of O2 (pO2) on photosynthetic characteristic parameters in sunflower (Helianthus annuus L.) leaves. Under low CO2 conditions, the oxidation of P700 was stimulated; however the decrease in pO2 suppressed its oxidation. Electron fluxes in PSII [Y(II)] and PSI [Y(I)] showed pO2-dependence at low CO2 conditions. H(+)-consumption rate, estimated from Y(II) and CO2-fixation/photorespiration rates (JgH(+)), showed the positive curvature relationship with the dissipation rate of electrochromic shift signal (V H (+) ), which indicates H(+)-efflux rate from lumen to stroma in chloroplasts. Therefore, these electron fluxes contained, besides CO2-fixation/photorespiration-dependent electron fluxes, non-H(+)-consumption electron fluxes including Mehler-ascorbate peroxidase (MAP)-pathway. Y(I) that was larger than Y(II) surely implies the functioning of cyclic electron flow (CEF). Both MAP-pathway and CEF were suppressed at lower pO2, with plastoquinone-pool reduced. That is, photorespiration prepares the redox-poise of photosynthetic electron transport system for CEF activity as an electron sink. Excess Y(II), [ΔY(II)] giving the curvature relationship with V H (+) , and excess Y(I) [ΔCEF] giving the difference between Y(I) and Y(II) were used as an indicator of MAP-pathway and CEF activity, respectively. Although ΔY(II) was negligible and did not show positive relationship to the oxidation-state of P700, ΔCEF showed positive linear relationship to the oxidation-state of P700. These facts indicate that CEF cooperatively with photorespiration regulates the redox-state of P700 to suppress the over-reduction in PSI under environmental stress conditions.
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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
| | - 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
| | - Takehiro Sejima
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
| | - Amane Makino
- Department of Applied Plant Science, Graduate School of Agricultural Science, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 981-8555, 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.
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67
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Yang JT, Preiser AL, Li Z, Weise SE, Sharkey TD. Triose phosphate use limitation of photosynthesis: short-term and long-term effects. PLANTA 2016; 243:687-98. [PMID: 26620947 DOI: 10.1007/s00425-015-2436-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 11/16/2015] [Indexed: 05/02/2023]
Abstract
MAIN CONCLUSION The triose phosphate use limitation was studied using long-term and short term changes in capacity. The TPU limitation caused increased proton motive force; long-term TPU limitation additionally reduced other photosynthetic components. Photosynthetic responses to CO2 can be interpreted primarily as being limited by the amount or activity of Rubisco or the capacity for ribulose bisphosphate regeneration, but at high rates of photosynthesis a third response is often seen. Photosynthesis becomes insensitive to CO2 or even declines with increasing CO2, and this behavior has been associated with a limitation of export of carbon from the Calvin-Benson cycle. It is often called the triose phosphate use (TPU) limitation. We studied the long-term consequences of this limitation using plants engineered to have reduced capacity for starch or sucrose synthesis. We studied short-term consequences using temperature as a method for changing the balance of carbon fixation capacity and TPU. A long-term and short-term TPU limitation resulted in an increase in proton motive force (PMF) in the thylakoids. Once a TPU limitation was reached, any further increases in CO2 was met with a further increase in the PMF but no increase or little increase in net assimilation of CO2. A long-term TPU limitation resulted in reduced Rubisco and RuBP regeneration capacity. We hypothesize that TPU, Rubisco activity, and RuBP regeneration are regulated so that TPU is normally in slight excess of what is required, and that this results in more effective regulation than if TPU were in large excess.
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Affiliation(s)
- Jennifer T Yang
- Department of Biochemistry and Molecular Biology, Michigan State University, 201 Biochemistry, 603 Wilson Rd, East Lansing, MI, 48824, USA
- Intercollege Program of Plant Biology, The Pennsylvania State University, State College, PA, 16802, USA
| | - Alyssa L Preiser
- Department of Biochemistry and Molecular Biology, Michigan State University, 201 Biochemistry, 603 Wilson Rd, East Lansing, MI, 48824, USA
| | - Ziru Li
- Department of Biochemistry and Molecular Biology, Michigan State University, 201 Biochemistry, 603 Wilson Rd, East Lansing, MI, 48824, USA
| | - Sean E Weise
- Department of Biochemistry and Molecular Biology, Michigan State University, 201 Biochemistry, 603 Wilson Rd, East Lansing, MI, 48824, USA
| | - Thomas D Sharkey
- Department of Biochemistry and Molecular Biology, Michigan State University, 201 Biochemistry, 603 Wilson Rd, East Lansing, MI, 48824, USA.
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68
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Herdean A, Nziengui H, Zsiros O, Solymosi K, Garab G, Lundin B, Spetea C. The Arabidopsis Thylakoid Chloride Channel AtCLCe Functions in Chloride Homeostasis and Regulation of Photosynthetic Electron Transport. FRONTIERS IN PLANT SCIENCE 2016; 7:115. [PMID: 26904077 PMCID: PMC4746265 DOI: 10.3389/fpls.2016.00115] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 01/21/2016] [Indexed: 05/20/2023]
Abstract
Chloride ions can be translocated across cell membranes through Cl(-) channels or Cl(-)/H(+) exchangers. The thylakoid-located member of the Cl(-) channel CLC family in Arabidopsis thaliana (AtCLCe) was hypothesized to play a role in photosynthetic regulation based on the initial photosynthetic characterization of clce mutant lines. The reduced nitrate content of Arabidopsis clce mutants suggested a role in regulation of plant nitrate homeostasis. In this study, we aimed to further investigate the role of AtCLCe in the regulation of ion homeostasis and photosynthetic processes in the thylakoid membrane. We report that the size and composition of proton motive force were mildly altered in two independent Arabidopsis clce mutant lines. Most pronounced effects in the clce mutants were observed on the photosynthetic electron transport of dark-adapted plants, based on the altered shape and associated parameters of the polyphasic OJIP kinetics of chlorophyll a fluorescence induction. Other alterations were found in the kinetics of state transition and in the macro-organization of photosystem II supercomplexes, as indicated by circular dichroism measurements. Pre-treatment with KCl but not with KNO3 restored the wild-type photosynthetic phenotype. Analyses by transmission electron microscopy revealed a bow-like arrangement of the thylakoid network and a large thylakoid-free stromal region in chloroplast sections from the dark-adapted clce plants. Based on these data, we propose that AtCLCe functions in Cl(-) homeostasis after transition from light to dark, which affects chloroplast ultrastructure and regulation of photosynthetic electron transport.
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Affiliation(s)
- Andrei Herdean
- Department of Biological and Environmental Sciences, University of GothenburgGothenburg, Sweden
| | - Hugues Nziengui
- Department of Biological and Environmental Sciences, University of GothenburgGothenburg, Sweden
| | - Ottó Zsiros
- Biological Research Center, Hungarian Academy of SciencesSzeged, Hungary
| | - Katalin Solymosi
- Department of Plant Anatomy, Eötvös Loránd UniversityBudapest, Hungary
| | - Győző Garab
- Biological Research Center, Hungarian Academy of SciencesSzeged, Hungary
| | - Björn Lundin
- Department of Biological and Environmental Sciences, University of GothenburgGothenburg, Sweden
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of GothenburgGothenburg, Sweden
- *Correspondence: Cornelia Spetea
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69
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Karlsson PM, Herdean A, Adolfsson L, Beebo A, Nziengui H, Irigoyen S, Ünnep R, Zsiros O, Nagy G, Garab G, Aronsson H, Versaw WK, Spetea C. The Arabidopsis thylakoid transporter PHT4;1 influences phosphate availability for ATP synthesis and plant growth. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 84:99-110. [PMID: 26255788 DOI: 10.1111/tpj.12962] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 07/14/2015] [Accepted: 08/03/2015] [Indexed: 05/24/2023]
Abstract
The Arabidopsis phosphate transporter PHT4;1 was previously localized to the chloroplast thylakoid membrane. Here we investigated the physiological consequences of the absence of PHT4;1 for photosynthesis and plant growth. In standard growth conditions, two independent Arabidopsis knockout mutant lines displayed significantly reduced leaf size and biomass but normal phosphorus content. When mutants were grown in high-phosphate conditions, the leaf phosphorus levels increased and the growth phenotype was suppressed. Photosynthetic measurements indicated that in the absence of PHT4;1 stromal phosphate was reduced to levels that limited ATP synthase activity. This resulted in reduced CO2 fixation and accumulation of soluble sugars, limiting plant growth. The mutants also displayed faster induction of non-photochemical quenching than the wild type, in line with the increased contribution of ΔpH to the proton-motive force across thylakoids. Small-angle neutron scattering showed a smaller lamellar repeat distance, whereas circular dichroism spectroscopy indicated a perturbed long-range order of photosystem II (PSII) complexes in the mutant thylakoids. The absence of PHT4;1 did not alter the PSII repair cycle, as indicated by wild-type levels of phosphorylation of PSII proteins, inactivation and D1 protein degradation. Interestingly, the expression of genes for several thylakoid proteins was downregulated in the mutants, but the relative levels of the corresponding proteins were either not affected or could not be discerned. Based on these data, we propose that PHT4;1 plays an important role in chloroplast phosphate compartmentation and ATP synthesis, which affect plant growth. It also maintains the ionic environment of thylakoids, which affects the macro-organization of complexes and induction of photoprotective mechanisms.
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Affiliation(s)
- Patrik M Karlsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, Gothenburg, 405 30, Sweden
| | - Andrei Herdean
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, Gothenburg, 405 30, Sweden
| | - Lisa Adolfsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, Gothenburg, 405 30, Sweden
| | - Azeez Beebo
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, Gothenburg, 405 30, Sweden
| | - Hugues Nziengui
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, Gothenburg, 405 30, Sweden
| | - Sonia Irigoyen
- Department of Biology, Texas A&M University, 3258, TAMU College Station, TX, 77843, USA
| | - Renáta Ünnep
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen PSI, 5232, Switzerland
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Box 49, Budapest, H-1525, Hungary
| | - Ottó Zsiros
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Box 521, Szeged, H-6701, Hungary
| | - Gergely Nagy
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen PSI, 5232, Switzerland
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Box 49, Budapest, H-1525, Hungary
| | - Győző Garab
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Box 521, Szeged, H-6701, Hungary
| | - Henrik Aronsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, Gothenburg, 405 30, Sweden
| | - Wayne K Versaw
- Department of Biology, Texas A&M University, 3258, TAMU College Station, TX, 77843, USA
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, Gothenburg, 405 30, Sweden
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70
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Tsabari O, Nevo R, Meir S, Carrillo LR, Kramer DM, Reich Z. Differential effects of ambient or diminished CO2 and O2 levels on thylakoid membrane structure in light-stressed plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 81:884-894. [PMID: 25619921 DOI: 10.1111/tpj.12774] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 01/13/2015] [Accepted: 01/14/2015] [Indexed: 06/04/2023]
Abstract
Over-reduction of the photosynthetic electron transport chain may severely damage the photosynthetic apparatus as well as other constituents of the chloroplast and the cell. Here, we exposed Arabidopsis leaves to saturating light either under normal atmospheric conditions or under CO2--and O2 -limiting conditions, which greatly increase excitation and electron pressures by draining terminal electron acceptors. The two treatments were found to have very different, often opposing, effects on the structure of the thylakoid membranes, including the width of the granal lumenal compartment. Modulation of the latter is proposed to be related to movements of ions across the thylakoid membrane, which alter the relative osmolarity of the lumen and stroma and affect the partitioning of the proton motive force into its electrical and osmotic components. The resulting changes in thylakoid organization and lumenal width should facilitate the repair of photodamaged photosystem II complexes in response to light stress under ambient conditions, but are expected to inhibit the repair cycle when the light stress occurs concurrently with CO2 and O2 depletion. Under the latter conditions, the changes in thylakoid structure are predicted to complement other processes that restrict the flow of electrons into the high-potential chain, thus moderating the production of deleterious reactive oxygen species at photosystem I.
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Affiliation(s)
- Onie Tsabari
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, 76100, Israel
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71
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Rühle T, Leister D. Assembly of F1F0-ATP synthases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:849-60. [PMID: 25667968 DOI: 10.1016/j.bbabio.2015.02.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 01/28/2015] [Accepted: 02/02/2015] [Indexed: 12/31/2022]
Abstract
F1F0-ATP synthases are multimeric protein complexes and common prerequisites for their correct assembly are (i) provision of subunits in appropriate relative amounts, (ii) coordination of membrane insertion and (iii) avoidance of assembly intermediates that uncouple the proton gradient or wastefully hydrolyse ATP. Accessory factors facilitate these goals and assembly occurs in a modular fashion. Subcomplexes common to bacteria and mitochondria, but in part still elusive in chloroplasts, include a soluble F1 intermediate, a membrane-intrinsic, oligomeric c-ring, and a membrane-embedded subcomplex composed of stator subunits and subunit a. The final assembly step is thought to involve association of the preformed F1-c10-14 with the ab2 module (or the ab8-stator module in mitochondria)--mediated by binding of subunit δ in bacteria or OSCP in mitochondria, respectively. Despite the common evolutionary origin of F1F0-ATP synthases, the set of auxiliary factors required for their assembly in bacteria, mitochondria and chloroplasts shows clear signs of evolutionary divergence. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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Affiliation(s)
- Thilo Rühle
- Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-Universität München (LMU), Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany.
| | - Dario Leister
- Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-Universität München (LMU), Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany.
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72
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Chaux F, Peltier G, Johnson X. A security network in PSI photoprotection: regulation of photosynthetic control, NPQ and O2 photoreduction by cyclic electron flow. FRONTIERS IN PLANT SCIENCE 2015; 6:875. [PMID: 26528325 PMCID: PMC4606052 DOI: 10.3389/fpls.2015.00875] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/02/2015] [Indexed: 05/18/2023]
Abstract
Cyclic electron flow (CEF) around PSI regulates acceptor-side limitations and has multiple functions in the green alga, Chlamydomonas reinhardtii. Here we draw on recent and historic literature and concentrate on its role in Photosystem I (PSI) photoprotection, outlining causes and consequences of damage to PSI and CEF's role as an avoidance mechanism. We outline two functions of CEF in PSI photoprotection that are both linked to luminal acidification: firstly, its action on Photosystem II with non-photochemical quenching and photosynthetic control and secondly, its action in poising the stroma to overcome acceptor-side limitation by rebalancing NADPH and ATP ratios for carbon fixation.
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Affiliation(s)
- Frédéric Chaux
- CEA, Direction des Sciences du Vivant, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, Saint-Paul-lez-Durance, France
- UMR Biologie Végétale et Microbiologie Environnementale, Centre National de la Recherche Scientifique, Saint-Paul-lez-Durance, France
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Aix Marseille Université, Saint-Paul-lez-Durance, France
| | - Gilles Peltier
- CEA, Direction des Sciences du Vivant, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, Saint-Paul-lez-Durance, France
- UMR Biologie Végétale et Microbiologie Environnementale, Centre National de la Recherche Scientifique, Saint-Paul-lez-Durance, France
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Aix Marseille Université, Saint-Paul-lez-Durance, France
| | - Xenie Johnson
- CEA, Direction des Sciences du Vivant, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, Saint-Paul-lez-Durance, France
- UMR Biologie Végétale et Microbiologie Environnementale, Centre National de la Recherche Scientifique, Saint-Paul-lez-Durance, France
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Aix Marseille Université, Saint-Paul-lez-Durance, France
- *Correspondence: Xenie Johnson,
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73
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Wang C, Yamamoto H, Shikanai T. Role of cyclic electron transport around photosystem I in regulating proton motive force. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1847:931-8. [PMID: 25481109 DOI: 10.1016/j.bbabio.2014.11.013] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 11/13/2014] [Accepted: 11/20/2014] [Indexed: 10/24/2022]
Abstract
In addition to ∆pH formed across the thylakoid membrane, membrane potential contributes to proton motive force (pmf) in chloroplasts. However, the regulation of photosynthetic electron transport is mediated solely by ∆pH. To assess the contribution of two cyclic electron transport pathways around photosystem I (one depending on PGR5/PGRL1 and one on NDH) to pmf formation, electrochromic shift (ECS) was analyzed in the Arabidopsis pgr5 mutant, NDH-defective mutants (ndhs and crr4-2), and their double mutants (ndhs pgr5 and crr4-2 pgr5). In pgr5, the size of the pmf, as represented by ECSt, was reduced by 30% to 47% compared with that in the wild type (WT). A gH+ parameter, which is considered to represent the activity of ATP synthase, was enhanced at high light intensities. However, gH+ recovered to its low-light levels after 20 min in the dark, implying that the elevation in gH+ is due to the disturbed regulation of ATP synthase rather than to photodamage. After long dark adaptation more than 2 h, gH+ was higher in pgr5 than in the WT. During induction of photosynthesis, gH+ was more rapidly elevated in pgr5 than that in the WT. Both results suggest that ATP synthase is not fully inactivated in the dark in pgr5. In the NDH-deficient mutants, ECSt was slightly but significantly lower than in the WT, whereas gH+ was not affected. In the double mutants, ECSt was even lower than in pgr5. These results suggest that both PGR5/PGRL1- and NDH-dependent pathways contribute to pmf formation, although to different extents. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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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
| | - 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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74
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Schöttler MA, Tóth SZ. Photosynthetic complex stoichiometry dynamics in higher plants: environmental acclimation and photosynthetic flux control. FRONTIERS IN PLANT SCIENCE 2014; 5:188. [PMID: 24860580 PMCID: PMC4026699 DOI: 10.3389/fpls.2014.00188] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 04/22/2014] [Indexed: 05/02/2023]
Abstract
The composition of the photosynthetic apparatus of higher plants is dynamically adjusted to long-term changes in environmental conditions such as growth light intensity and light quality, and to changing metabolic demands for ATP and NADPH imposed by stresses and leaf aging. By changing photosynthetic complex stoichiometry, a long-term imbalance between the photosynthetic production of ATP and NADPH and their metabolic consumption is avoided, and cytotoxic side reactions are minimized. Otherwise, an excess capacity of the light reactions, relative to the demands of primary metabolism, could result in a disturbance of cellular redox homeostasis and an increased production of reactive oxygen species, leading to the destruction of the photosynthetic apparatus and the initiation of cell death programs. In this review, changes of the abundances of the different constituents of the photosynthetic apparatus in response to environmental conditions and during leaf ontogenesis are summarized. The contributions of the different photosynthetic complexes to photosynthetic flux control and the regulation of electron transport are discussed.
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Affiliation(s)
- Mark A. Schöttler
- Max Planck Institute of Molecular Plant PhysiologyPotsdam-Golm, Germany
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75
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Long-term and short-term responses of the photosynthetic electron transport to fluctuating light. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2014; 137:89-99. [PMID: 24776379 DOI: 10.1016/j.jphotobiol.2014.02.016] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 02/19/2014] [Accepted: 02/22/2014] [Indexed: 12/26/2022]
Abstract
Light energy absorbed by chloroplasts drives photosynthesis. When absorbed light is in excess, the thermal dissipation systems of excess energy are induced and the photosynthetic electron flow is regulated, both contributing to suppression of reactive oxygen species production and photodamages. Various regulation mechanisms of the photosynthetic electron flow and energy dissipation systems have been revealed. However, most of such knowledge has been obtained by the experiments conducted under controlled conditions with constant light, whereas natural light condition is drastically fluctuated. To understand photosynthesis in nature, we need to clarify not only the mechanisms that raise photosynthetic efficiency but those for photoprotection in fluctuating light. Although these mechanisms appear to be well balanced, regulatory mechanisms achieving the balance is little understood. Recently, some pioneering studies have provided new insight into the regulatory mechanisms in fluctuating light. In this review, firstly, the possible mechanisms involved in regulation of the photosynthetic electron flow in fluctuating light are presented. Next, we introduce some recent studies focusing on the photosynthetic electron flow in fluctuating light. Finally, we discuss how plants effectively cope with fluctuating light showing our recent results.
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76
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Kohzuma K, Dal Bosco C, Meurer J, Kramer DM. Light- and metabolism-related regulation of the chloroplast ATP synthase has distinct mechanisms and functions. J Biol Chem 2013; 288:13156-63. [PMID: 23486473 DOI: 10.1074/jbc.m113.453225] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The chloroplast CF0-CF1-ATP synthase (ATP synthase) is activated in the light and inactivated in the dark by thioredoxin-mediated redox modulation of a disulfide bridge on its γ subunit. The activity of the ATP synthase is also fine-tuned during steady-state photosynthesis in response to metabolic changes, e.g. altering CO2 levels to adjust the thylakoid proton gradient and thus the regulation of light harvesting and electron transfer. The mechanism of this fine-tuning is unknown. We test here the possibility that it also involves redox modulation. We found that modifying the Arabidopsis thaliana γ subunit by mutating three highly conserved acidic amino acids, D211V, E212L, and E226L, resulted in a mutant, termed mothra, in which ATP synthase which lacked light-dark regulation had relatively small effects on maximal activity in vivo. In situ equilibrium redox titrations and thiol redox-sensitive labeling studies showed that the γ subunit disulfide/sulfhydryl couple in the modified ATP synthase has a more reducing redox potential and thus remains predominantly oxidized under physiological conditions, implying that the highly conserved acidic residues in the γ subunit influence thiol redox potential. In contrast to its altered light-dark regulation, mothra retained wild-type fine-tuning of ATP synthase activity in response to changes in ambient CO2 concentrations, indicating that the light-dark- and metabolic-related regulation occur through different mechanisms, possibly via small molecule allosteric effectors or covalent modification.
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Affiliation(s)
- Kaori Kohzuma
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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77
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Thioredoxin-insensitive plastid ATP synthase that performs moonlighting functions. Proc Natl Acad Sci U S A 2012; 109:3293-8. [PMID: 22328157 DOI: 10.1073/pnas.1115728109] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The chloroplast ATP synthase catalyzes the light-driven synthesis of ATP and acts as a key feedback regulatory component of photosynthesis. Arabidopsis possesses two homologues of the regulatory γ subunit of the ATP synthase, encoded by the ATPC1 and ATPC2 genes. Using a series of mutants, we show that both these subunits can support photosynthetic ATP synthesis in vivo with similar specific activities, but that in wild-type plants, only γ(1) is involved in ATP synthesis in photosynthesis. The γ(1)-containing ATP synthase shows classical light-induced redox regulation, whereas the mutant expressing only γ(2)-ATP synthase (gamma exchange-revised ATP synthase, gamera) shows equally high ATP synthase activity in the light and dark. In situ redox titrations demonstrate that the regulatory thiol groups on γ(2)-ATP synthase remain reduced under physiological conditions but can be oxidized by the strong oxidant diamide, implying that the redox potential for the thiol/disulphide transition in γ(2) is substantially higher than that for γ(1). This regulatory difference may be attributed to alterations in the residues near the redox-active thiols. We propose that γ(2)-ATP synthase functions to catalyze ATP hydrolysis-driven proton translocation in nonphotosynthetic plastids, maintaining a sufficient transthylakoid proton gradient to drive protein translocation or other processes. Consistent with this interpretation, ATPC2 is predominantly expressed in the root, whereas modifying its expression results in alteration of root hair development. Phylogenetic analysis suggests that γ(2) originated from ancient gene duplication, resulting in divergent evolution of functionally distinct ATP synthase complexes in dicots and mosses.
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78
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Foyer CH, Neukermans J, Queval G, Noctor G, Harbinson J. Photosynthetic control of electron transport and the regulation of gene expression. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:1637-61. [PMID: 22371324 DOI: 10.1093/jxb/ers013] [Citation(s) in RCA: 273] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The term 'photosynthetic control' describes the short- and long-term mechanisms that regulate reactions in the photosynthetic electron transport (PET) chain so that the rate of production of ATP and NADPH is coordinated with the rate of their utilization in metabolism. At low irradiances these mechanisms serve to optimize light use efficiency, while at high irradiances they operate to dissipate excess excitation energy as heat. Similarly, the production of ATP and NADPH in ratios tailored to meet demand is finely tuned by a sophisticated series of controls that prevents the accumulation of high NAD(P)H/NAD(P) ratios and ATP/ADP ratios that would lead to potentially harmful over-reduction and inactivation of PET chain components. In recent years, photosynthetic control has also been extrapolated to the regulation of gene expression because mechanisms that are identical or similar to those that serve to regulate electron flow through the PET chain also coordinate the regulated expression of genes encoding photosynthetic proteins. This requires coordinated gene expression in the chloroplasts, mitochondria, and nuclei, involving complex networks of forward and retrograde signalling pathways. Photosynthetic control operates to control photosynthetic gene expression in response to environmental and metabolic changes. Mining literature data on transcriptome profiles of C(3) and C(4) leaves from plants grown under high atmospheric carbon dioxide (CO(2)) levels compared with those grown with ambient CO(2) reveals that the transition to higher photorespiratory conditions in C(3) plants enhances the expression of genes associated with cyclic electron flow pathways in Arabidopsis thaliana, consistent with the higher ATP requirement (relative to NADPH) of photorespiration.
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Affiliation(s)
- Christine H Foyer
- Centre for Plant Sciences, Faculty of Biology, University of Leeds, Leeds LS2 9JT, UK.
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79
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Zhang R, Kramer DM, Cruz JA, Struck KR, Sharkey TD. The effects of moderately high temperature on zeaxanthin accumulation and decay. PHOTOSYNTHESIS RESEARCH 2011; 108:171-81. [PMID: 21785990 DOI: 10.1007/s11120-011-9672-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Accepted: 07/08/2011] [Indexed: 05/31/2023]
Abstract
Moderately high temperature reduces photosynthetic capacities of leaves with large effects on thylakoid reactions of photosynthesis, including xanthophyll conversion in the lipid phase of the thylakoid membrane. In previous studies, we have found that leaf temperature of 40°C increased zeaxanthin accumulation in dark-adapted, intact tobacco leaves following a brief illumination, but did not change the amount of zeaxanthin in light-adatped leaves. To investigate heat effects on zeaxanthin accumulation and decay, zeaxanthin level was monitored optically in dark-adapted, intact tobacco and Arabidopsis thaliana leaves at either 23 or 40°C under 45-min illumination. Heated leaves had more zeaxanthin following 3-min light but had less or comparable amounts of zeaxanthin by the end of 45 min of illumination. Zeaxanthin accumulated faster at light initiation and decayed faster upon darkening in leaves at 40°C than leaves at 23°C, indicating that heat increased the activities of both violaxanthin de-epoxidase (VDE) and zeaxanthin epoxidase (ZE). In addition, our optical measurement demonstrated in vivo that weak light enhances zeaxanthin decay relative to darkness in intact leaves of tobacco and Arabidopsis, confirming previous observations in isolated spinach chloroplasts. However, the maximum rate of decay is similar for weak light and darkness, and we used the maximum rate of decay following darkness as a measure of the rate of ZE during steady-state light. A simulation indicated that high temperature should cause a large shift in the pH dependence of the amount of zeaxanthin in leaves because of differential effects on VDE and ZE. This allows for the reduction in ΔpH caused by heat to be offset by increased VDE activity relative to ZE.
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Affiliation(s)
- Ru Zhang
- Department of Plant Biology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA 94305, USA.
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80
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Yamori W, Takahashi S, Makino A, Price GD, Badger MR, von Caemmerer S. The roles of ATP synthase and the cytochrome b6/f complexes in limiting chloroplast electron transport and determining photosynthetic capacity. PLANT PHYSIOLOGY 2011; 155:956-62. [PMID: 21177473 PMCID: PMC3032479 DOI: 10.1104/pp.110.168435] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 12/16/2010] [Indexed: 05/18/2023]
Abstract
In C(3) plants, CO(2) assimilation is limited by ribulose 1,5-bisphosphate (RuBP) regeneration rate at high CO(2). RuBP regeneration rate in turn is determined by either the chloroplast electron transport capacity to generate NADPH and ATP or the activity of Calvin cycle enzymes involved in regeneration of RuBP. Here, transgenic tobacco (Nicotiana tabacum 'W38') expressing an antisense gene directed at the transcript of either the Rieske iron-sulfur protein of the cytochrome (Cyt) b(6)/f complex or the δ-subunit of chloroplast ATP synthase have been used to investigate the effect of a reduction of these complexes on chloroplast electron transport rate (ETR). Reductions in δ-subunit of ATP synthase content did not alter chlorophyll, Cyt b(6)/f complex, or Rubisco content, but reduced ETR estimated either from measurements of chlorophyll fluorescence or CO(2) assimilation rates at high CO(2). Plants with low ATP synthase content exhibited higher nonphotochemical quenching and achieved higher ETR per ATP synthase than the wild type. The proportional increase in ETR per ATP synthase complex was greatest at 35°C, showing that the ATP synthase activity can vary in vivo. In comparison, there was no difference in the ETR per Cyt b(6)/f complex in plants with reduced Cyt b(6)/f content and the wild type. The ETR decreased more drastically with reductions in Cyt b(6)/f complex than ATP synthase content. This suggests that chloroplast ETR is more limited by Cyt b(6)/f than ATP synthase content and is a potential target for enhancing photosynthetic capacity in crops.
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Affiliation(s)
- Wataru Yamori
- Molecular Plant Physiology Cluster, Plant Science Division, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia.
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81
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Livingston AK, Kanazawa A, Cruz JA, Kramer DM. Regulation of cyclic electron flow in C₃ plants: differential effects of limiting photosynthesis at ribulose-1,5-bisphosphate carboxylase/oxygenase and glyceraldehyde-3-phosphate dehydrogenase. PLANT, CELL & ENVIRONMENT 2010; 33:1779-88. [PMID: 20545877 DOI: 10.1111/j.1365-3040.2010.02183.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Cyclic electron flow around photosystem I (CEF1) is thought to augment chloroplast ATP production to meet metabolic needs. Very little is known about the induction and regulation of CEF1. We investigated the effects on CEF1 of antisense suppression of the Calvin-Benson enzymes glyceraldehyde-3-phosphate dehydrogenase (gapR), and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) small subunit (SSU), in tobacco (Nicotiana tabacum cv. Wisconsin 38). The gapR, but not ssuR, mutants showed substantial increases in CEF1, demonstrating that specific intermediates, rather than slowing of assimilation, induce CEF1. Both types of mutant showed increases in steady-state transthylakoid proton motive force (pmf) and subsequent activation of the photoprotective q(E) response. With gapR, the increased pmf was caused both by up-regulation of CEF1 and down-regulation of the ATP synthase. In ssuR, the increased pmf was attributed entirely to a decrease in ATP synthase activity, as previously seen in wild-type plants when CO₂ levels were decreased. Comparison of major stromal metabolites in gapR, ssuR and hcef1, a mutant with decreased fructose 1,6-bisphosphatase activity, showed that neither the ATP/ADP ratio, nor major Calvin-Benson cycle intermediates can directly account for the activation of CEF1, suggesting that chloroplast redox status or reactive oxygen species regulate CEF1.
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Affiliation(s)
- Aaron K Livingston
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340, USA
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82
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Livingston AK, Cruz JA, Kohzuma K, Dhingra A, Kramer DM. An Arabidopsis mutant with high cyclic electron flow around photosystem I (hcef) involving the NADPH dehydrogenase complex. THE PLANT CELL 2010; 22:221-33. [PMID: 20081115 PMCID: PMC2828696 DOI: 10.1105/tpc.109.071084] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 12/02/2009] [Accepted: 12/23/2009] [Indexed: 05/18/2023]
Abstract
Cyclic electron flow (CEFI) has been proposed to balance the chloroplast energy budget, but the pathway, mechanism, and physiological role remain unclear. We isolated a new class of mutant in Arabidopsis thaliana, hcef for high CEF1, which shows constitutively elevated CEF1. The first of these, hcef1, was mapped to chloroplast fructose-1,6-bisphosphatase. Crossing hcef1 with pgr5, which is deficient in the antimycin A-sensitive pathway for plastoquinone reduction, resulted in a double mutant that maintained the high CEF1 phenotype, implying that the PGR5-dependent pathway is not involved. By contrast, crossing hcef1 with crr2-2, deficient in thylakoid NADPH dehydrogenase (NDH) complex, results in a double mutant that is highly light sensitive and lacks elevated CEF1, suggesting that NDH plays a direct role in catalyzing or regulating CEF1. Additionally, the NdhI component of the NDH complex was highly expressed in hcef1, whereas other photosynthetic complexes, as well as PGR5, decreased. We propose that (1) NDH is specifically upregulated in hcef1, allowing for increased CEF1; (2) the hcef1 mutation imposes an elevated ATP demand that may trigger CEF1; and (3) alternative mechanisms for augmenting ATP cannot compensate for the loss of CEF1 through NDH.
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Affiliation(s)
- Aaron K. Livingston
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
| | - Jeffrey A. Cruz
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
| | - Kaori Kohzuma
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
| | - Amit Dhingra
- Horticulture and Landscape Architecture, Washington State University, Pullman, Washington 99164-6340
| | - David M. Kramer
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
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83
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Zhang R, Cruz JA, Kramer DM, Magallanes-Lundback ME, Dellapenna D, Sharkey TD. Moderate heat stress reduces the pH component of the transthylakoid proton motive force in light-adapted, intact tobacco leaves. PLANT, CELL & ENVIRONMENT 2009; 32:1538-47. [PMID: 19558623 DOI: 10.1111/j.1365-3040.2009.02018.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We measured the DeltaPsi and DeltapH components of the transthylakoid proton motive force (pmf) in light-adapted, intact tobacco leaves in response to moderate heat. The DeltaPsi causes an electrochromic shift (ECS) in carotenoid absorbance spectra. The light-dark difference spectrum has a peak at 518 nm and the two components of the pmf were separated by following the ECS for 25 s after turning the light off. The ECS signal was deconvoluted by subtracting the effects of zeaxanthin formation (peak at 505 nm) and the qE-related absorbance changes (peak at 535 nm) from a signal measured at 520 nm. Heat reduced DeltapH while DeltaPsi slightly increased. Elevated temperature accelerated ECS decay kinetics likely reflecting heat-induced increases in proton conductance and ion movement. Energy-dependent quenching (qE) was reduced by heat. However, the reduction of qE was less than expected given the loss of DeltapH. Zeaxanthin did not increase with heat in light-adapted leaves but it was higher than would be predicted given the reduced DeltapH found at high temperature. The results indicate that moderate heat stress can have very large effects on thylakoid reactions.
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Affiliation(s)
- Ru Zhang
- Department of Botany, University of Wisconsin-Madison, Madison, WI 53706, USA
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84
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Kiirats O, Cruz JA, Edwards GE, Kramer DM. Feedback limitation of photosynthesis at high CO 2 acts by modulating the activity of the chloroplast ATP synthase. FUNCTIONAL PLANT BIOLOGY : FPB 2009; 36:893-901. [PMID: 32688700 DOI: 10.1071/fp09129] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Accepted: 08/11/2009] [Indexed: 06/11/2023]
Abstract
It was previously shown that photosynthetic electron transfer is controlled under low CO2 via regulation of the chloroplast ATP synthase. In the current work, we studied the regulation of photosynthesis under feedback limiting conditions, where photosynthesis is limited by the capacity to utilise triose-phosphate for synthesis of end products (starch or sucrose), in a starch-deficient mutant of Nicotiana sylvestris Speg. & Comes. At high CO2, we observed feedback control that was progressively reversed by increasing O2 levels from 2 to 40%. The activity of the ATP synthase, probed in vivo by the dark-interval relaxation kinetics of the electrochromic shift, was proportional to the O2-induced increases in O2 evolution from PSII (JO2), as well as the sum of Rubisco oxygenation (vo) and carboxylation (vc) rates. The altered ATP synthase activity led to changes in the light-driven proton motive force, resulting in regulation of the rate of plastoquinol oxidation at the cytochrome b6f complex, quantitatively accounting for the observed control of photosynthetic electron transfer. The ATP content of the cell decreases under feedback limitation, suggesting that the ATP synthesis was downregulated to a larger extent than ATP consumption. This likely resulted in slowing of ribulose bisphosphate regeneration and JO2). Overall, our results indicate that, just as at low CO2, feedback limitations control the light reactions of photosynthesis via regulation of the ATP synthase, and can be reconciled with regulation via stromal Pi, or an unknown allosteric affector.
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Affiliation(s)
- Olavi Kiirats
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4238, USA
| | - Jeffrey A Cruz
- Institute of Biological Chemistry, 339 Clark Hall, Washington State University, Pullman, WA 99164-6340, USA
| | - Gerald E Edwards
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4238, USA
| | - David M Kramer
- Institute of Biological Chemistry, 339 Clark Hall, Washington State University, Pullman, WA 99164-6340, USA
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85
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Kohzuma K, Cruz JA, Akashi K, Hoshiyasu S, Munekage YN, Yokota A, Kramer DM. The long-term responses of the photosynthetic proton circuit to drought. PLANT, CELL & ENVIRONMENT 2009; 32:209-19. [PMID: 19021886 DOI: 10.1111/j.1365-3040.2008.01912.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Proton motive force (pmf) across thylakoid membranes is not only for harnessing solar energy for photosynthetic CO(2) fixation, but also for triggering feedback regulation of photosystem II antenna. The mechanisms for balancing these two roles of the proton circuit under the long-term environmental stress, such as prolonged drought, have been poorly understood. In this study, we report on the response of wild watermelon thylakoid 'proton circuit' to drought stress using both in vivo spectroscopy and molecular analyses of the representative photosynthetic components. Although drought stress led to enhanced proton flux via a approximately 34% increase in cyclic electron flow around photosystem I (PS I), an observed approximately fivefold decrease in proton conductivity, g(H)(+), across thylakoid membranes suggested that decreased ATP synthase activity was the major factor for sustaining elevated q(E). Western blotting analyses revealed that ATP synthase content decreased significantly, suggesting that quantitative control of the complex plays a pivotal role in down-regulation of g(H)(+). The expression level of cytochrome b(6)f complex - another key control point in photosynthesis - also declined, probably to prevent excess-reduction of PS I electron acceptors. We conclude that plant acclimation to long-term environmental stress involves global changes in the photosynthetic proton circuit, in which ATP synthase represents the key control point for regulating the relationship between electron transfer and pmf.
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Affiliation(s)
- Kaori Kohzuma
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan
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86
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Takizawa K, Takahashi S, Hüner NPA, Minagawa J. Salinity affects the photoacclimation of Chlamydomonas raudensis Ettl UWO241. PHOTOSYNTHESIS RESEARCH 2009; 99:195-203. [PMID: 19137412 DOI: 10.1007/s11120-008-9397-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 12/23/2008] [Indexed: 05/09/2023]
Abstract
Chlamydomonas raudensis Ettl UWO241, a natural variant of C. raudensis, is deficient in state transitions. Its habitat, the deepest layer of Lake Bonney in Antarctica, features low irradiance, low temperature, and high salinity. Although psychrophily and low-light acclimation of this green alga has been described, very little information is available on the effect of salinity. Here, we demonstrate that this psychrophile is halotolerant, not halophilic, and it shows energy redistribution between photosystem I and II based on energy spillover under low-salt conditions. Furthermore, we revealed that C. raudensis exhibits higher non-photochemical quenching in comparison with the mesophile Chlamydomonas reinhardtii, when grown with low-salt, which is due to the lower proton conductivity across the thylakoid membrane. Significance of the C. raudensis UWO241 traits found in the low salinity culture are implicated with their natural habitats, including the high salinity and extremely stable light environments.
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Affiliation(s)
- Kenji Takizawa
- Institute of Low Temperature Science, Hokkaido University, Sapporo, 060-0819, Japan
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87
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Lawlor DW, Tezara W. Causes of decreased photosynthetic rate and metabolic capacity in water-deficient leaf cells: a critical evaluation of mechanisms and integration of processes. ANNALS OF BOTANY 2009; 103:561-79. [PMID: 19155221 PMCID: PMC2707350 DOI: 10.1093/aob/mcn244] [Citation(s) in RCA: 293] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 08/27/2008] [Accepted: 11/10/2008] [Indexed: 05/18/2023]
Abstract
BACKGROUND Water deficit (WD) decreases photosynthetic rate (A) via decreased stomatal conductance to CO(2) (g(s)) and photosynthetic metabolic potential (A(pot)). The relative importance of g(s) and A(pot), and how they are affected by WD, are reviewed with respect to light intensity and to experimental approaches. SCOPE AND CONCLUSIONS With progressive WD, A decreases as g(s) falls. Under low light during growth and WD, A is stimulated by elevated CO(2), showing that metabolism (A(pot)) is not impaired, but at high light A is not stimulated, showing inhibition. At a given intercellular CO(2) concentration (C(i)) A decreases, showing impaired metabolism (A(pot)). The C(i) and probably chloroplast CO(2) concentration (C(c)), decreases and then increases, together with the equilibrium CO(2) concentration, with greater WD. Estimation of C(c) and internal (mesophyll) conductance (g(i)) is considered uncertain. Photosystem activity is unaffected until very severe WD, maintaining electron (e(-)) transport (ET) and reductant content. Low A, together with photorespiration (PR), which is maintained or decreased, provides a smaller sink for e(-)(,) causing over-energization of energy transduction. Despite increased non-photochemical quenching (NPQ), excess energy and e(-) result in generation of reactive oxygen species (ROS). Evidence is considered that ROS damages ATP synthase so that ATP content decreases progressively with WD. Decreased ATP limits RuBP production by the Calvin cycle and thus A(pot). Rubisco activity is unlikely to determine A(pot). Sucrose synthesis is limited by lack of substrate and impaired enzyme regulation. With WD, PR decreases relative to light respiration (R(L)), and mitochondria consume reductant and synthesise ATP. With progressing WD at low A, R(L) increases C(i) and C(c). This review emphasises the effects of light intensity, considers techniques, and develops a qualitative model of photosynthetic metabolism under WD that explains many observations: testable hypotheses are suggested.
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Affiliation(s)
- David W Lawlor
- Plant Sciences, Centre for Crop Improvement, Rothamsted Research, Harpenden, Herts, UK.
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Abstract
Plants and algae often absorb too much light-more than they can actually use in photosynthesis. To prevent photo-oxidative damage and to acclimate to changes in their environment, photosynthetic organisms have evolved direct and indirect mechanisms for sensing and responding to excess light. Photoreceptors such as phototropin, neochrome, and cryptochrome can sense excess light directly and relay signals for chloroplast movement and gene expression responses. Indirect sensing of excess light through biochemical and metabolic signals can be transduced into local responses within chloroplasts, into changes in nuclear gene expression via retrograde signaling pathways, or even into systemic responses, all of which are associated with photoacclimation.
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Affiliation(s)
- Zhirong Li
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
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89
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Guo B, Irigoyen S, Fowler TB, Versaw WK. Differential expression and phylogenetic analysis suggest specialization of plastid-localized members of the PHT4 phosphate transporter family for photosynthetic and heterotrophic tissues. PLANT SIGNALING & BEHAVIOR 2008; 3:784-90. [PMID: 19513231 PMCID: PMC2634373 DOI: 10.4161/psb.3.10.6666] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Accepted: 07/23/2008] [Indexed: 05/20/2023]
Abstract
Plastids rely on multiple phosphate (Pi) transport activities to support and control a wide range of metabolic processes, including photosynthesis and carbon partitioning. Five of the six members of the PHT4 family of Pi transporters in Arabidopsis thaliana (PHT4;1-PHT4;5) are confirmed or predicted plastid proteins. As a step towards identifying the roles of individual PHT4 Pi transporters in chloroplast and non-photosynthetic plastid Pi dynamics, we used promoter-reporter gene fusions and quantitative RT-PCR studies, respectively, to determine spatial and diurnal gene expression patterns. PHT4;1 and PHT4;4 were both expressed predominantly in photosynthetic tissues, although expression of PHT4;1 was circadian and PHT4;4 was induced by light. PHT4;3 and PHT4;5 were expressed mainly in leaf phloem. PHT4;2 was expressed throughout the root, and exhibited a diurnal pattern with peak transcript levels in the dark. The remaining member of this gene family, PHT4;6, encodes a Golgi-localized protein and was expressed ubiquitously. The overlapping but distinct expression patterns for these genes suggest specialized roles for the encoded transporters in multiple types of differentiated plastids. Phylogenetic analysis revealed conservation of each of the orthologous members of the PHT4 family in Arabidopsis and rice, which is consistent with specialization, and suggests that the individual members of this transporter family diverged prior to the divergence of monocots and dicots.
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Affiliation(s)
- Biwei Guo
- Department of Biology; Texas A&M University; College Station, Texas USA
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Pavón LR, Lundh F, Lundin B, Mishra A, Persson BL, Spetea C. Arabidopsis ANTR1 Is a Thylakoid Na+-dependent Phosphate Transporter. J Biol Chem 2008; 283:13520-7. [DOI: 10.1074/jbc.m709371200] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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