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Zhang X, Chen J, Wang W, Zhu L. Photosynthetic mechanisms of carbon fixation reduction in rice by cadmium and polycyclic aromatic hydrocarbons. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 344:123436. [PMID: 38281573 DOI: 10.1016/j.envpol.2024.123436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/21/2024] [Accepted: 01/21/2024] [Indexed: 01/30/2024]
Abstract
Environmental pollutants interfere with plant photosynthesis, thus reduce the crop yield and carbon storage capacity of farmland. This study comparatively explored the effects and mechanisms of polycyclic aromatic hydrocarbons (PAHs, e.g., phenanthrene, pyrene, and benzo[a]pyrene) and cadmium (Cd) on the carbon fixation capacity of rice throughout the growth period. Cd posed severer inhibition on the net carbon fixation of rice than PAHs, with the inhibition rates of 1.40-14.8-fold over PAHs at the concentrations of 0.5 or 5 mg/kg soil. Ribulose diphosphate carboxylase/oxygenase (Rubisco) involved in the Calvin cycle was identified as the common target of these pollutants to inhibit the photosynthetic carbon fixation. Further investigation demonstrated that the different inhibitory effects of Cd and PAHs was resulted from their different interference on the dual catalysis function (carboxylation and oxygenation) of Rubisco. Cd disturbed the balance of the intercellular CO2/O2, thus promoting the oxygenation and inhibiting the carboxylation of the substrate of Rubisco. Under the stress of Cd, the downstream metabolites (e.g. glycolate, glyoxylate, and serine) of Rubisco oxygenation were upregulated by over 2.01-3.24-fold, whereas the carboxylation efficiency (Vcmax) was decreased by 5.58-29.3%. Comparatively, PAHs inhibited both the carboxylation and oxygenation by down-regulating the expression of Rubisco coding gene (OsRBCS2, Log2FC < -2). This study broadens the understanding of the mechanisms of different environmental pollutants on the carbon fixation, providing valuable information for the quantitative estimation of their impacts on the farmland carbon sink. The results would be constructive to develop strategies for eliminating the adverse effects of contaminants and assist the carbon-neutral programs.
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Affiliation(s)
- Xinru Zhang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang, 310058, China
| | - Jie Chen
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang, 310058, China
| | - Wei Wang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang, 310058, China
| | - Lizhong Zhu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang, 310058, China.
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2
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Ludwig M, Hartwell J, Raines CA, Simkin AJ. The Calvin-Benson-Bassham cycle in C 4 and Crassulacean acid metabolism species. Semin Cell Dev Biol 2024; 155:10-22. [PMID: 37544777 DOI: 10.1016/j.semcdb.2023.07.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 07/03/2023] [Accepted: 07/25/2023] [Indexed: 08/08/2023]
Abstract
The Calvin-Benson-Bassham (CBB) cycle is the ancestral CO2 assimilation pathway and is found in all photosynthetic organisms. Biochemical extensions to the CBB cycle have evolved that allow the resulting pathways to act as CO2 concentrating mechanisms, either spatially in the case of C4 photosynthesis or temporally in the case of Crassulacean acid metabolism (CAM). While the biochemical steps in the C4 and CAM pathways are known, questions remain on their integration and regulation with CBB cycle activity. The application of omic and transgenic technologies is providing a more complete understanding of the biochemistry of C4 and CAM species and will also provide insight into the CBB cycle in these plants. As the global population increases, new solutions are required to increase crop yields and meet demands for food and other bioproducts. Previous work in C3 species has shown that increasing carbon assimilation through genetic manipulation of the CBB cycle can increase biomass and yield. There may also be options to improve photosynthesis in species using C4 photosynthesis and CAM through manipulation of the CBB cycle in these plants. This is an underexplored strategy and requires more basic knowledge of CBB cycle operation in these species to enable approaches for increased productivity.
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Affiliation(s)
- Martha Ludwig
- School of Molecular Sciences, University of Western Australia, Perth, Western Australia, Australia.
| | - James Hartwell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | | | - Andrew J Simkin
- University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK; School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
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3
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Gregory LM, Tejera-Nieves M, Walker BJ. Measuring and Quantifying Characteristics of the Post-illumination Burst. Methods Mol Biol 2024; 2792:115-124. [PMID: 38861082 DOI: 10.1007/978-1-0716-3802-6_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
Leaf-level gas exchange enables accurate measurements of net CO2 assimilation in the light, as well as CO2 respiration in the dark. Net positive CO2 assimilation in the light indicates that the gain of carbon by photosynthesis offsets the photorespiratory loss of CO2 and respiration of CO2 in the light (RL), while the CO2 respired in the dark is mainly attributed to respiration in the dark (RD). Measuring the CO2 release specifically from photorespiration in the light is challenging since net CO2 assimilation involves three concurrent processes (the velocity of rubisco carboxylation; vc, velocity of rubisco oxygenation; vo, and RL). However, by employing a rapid light-dark transient, it is possible to transiently measure some of the CO2 release from photorespiration without the background of vc-based assimilation in the dark. This method is commonly known as the post-illumination CO2 burst (PIB) and results in a "burst" of CO2 immediately after the transition to the dark. This burst can be quantitatively characterized using several approaches. Here, we describe how to set up a PIB measurement and provide some guidelines on how to analyze and interpret the data obtained using a PIB analysis application developed in R.
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Affiliation(s)
- Luke M Gregory
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - Mauricio Tejera-Nieves
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA
| | - Berkley J Walker
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI, USA.
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA.
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA.
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4
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Fu X, Walker BJ. Using Dynamic Gas Exchange Measurements During Oxygen Transients to Study Nonsteady-State Photorespiration. Methods Mol Biol 2024; 2792:175-184. [PMID: 38861087 DOI: 10.1007/978-1-0716-3802-6_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
Leaf-level gas exchange is widely used to investigate the largest carbon fluxes in illuminated leaves, offering a nondestructive way to investigate the impact of photorespiration on plant carbon balance. Modern commercial gas exchange systems allow high temporal resolution measurements under changing environments, aiding the development of nonsteady-state approaches for measuring dynamic photosynthetic responses. Here, we describe a nonsteady-state technique for acquiring the dynamic response of net CO2 assimilation to changes in photorespiratory fluxes manipulated by O2 mole fractions. This technique allows for the screening of plant genotypes with variations in their efficiencies of photorespiration under nonsteady-state conditions.
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Affiliation(s)
- Xinyu Fu
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
| | - Berkley J Walker
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI, USA.
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA.
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5
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Abadie C, Lalande J, Tcherkez G. Combining Gas Exchange and Rapid Quenching of Leaf Tissue for Mass Spectrometry and NMR Analysis Using an External Chamber. Methods Mol Biol 2024; 2792:195-208. [PMID: 38861089 DOI: 10.1007/978-1-0716-3802-6_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
We describe here a method to study and manipulate photorespiration in intact illuminated leaves. When the CO2/O2 mole fraction ratio changes, instant sampling is critical, to quench leaf metabolism and thus trace rapid metabolic modification due to gaseous conditions. To do so, we combine 13CO2 labeling and gas exchange, using a large custom leaf chamber to facilitate fast sampling by direct liquid nitrogen spraying. Moreover, the use of a high chamber surface area (about 130 cm2) allows one to sample a large amount of leaf material to carry out 13C-nuclear magnetic resonance (NMR) analysis and complementary analyses, such as isotopic analyses by high-resolution mass spectrometry (by both GC and LC-MS). 13C-NMR gives access to absolute 13C amounts at the specific carbon atom position in the labeled molecules and thereby provides an estimate of 13C-flux of photorespiratory intermediates. Since NMR analysis is not very sensitive and can miss minor metabolites, GC or LC-MS analyses are useful to monitor metabolites at low concentrations. Furthermore, 13C-NMR and high-resolution LC-MS allow to estimate isotopologue distribution in response to 13CO2 labeling while modifying photorespiration activity.
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Affiliation(s)
- Cyril Abadie
- Institut de Recherche en Horticulture et Semences, Université d'Angers, Beaucouzé, France
| | - Julie Lalande
- Institut de Recherche en Horticulture et Semences, Université d'Angers, Beaucouzé, France
| | - Guillaume Tcherkez
- Institut de Recherche en Horticulture et Semences, Université d'Angers, Beaucouzé, France.
- Research School of Biology, Australian National University, Canberra, ACT, Australia.
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6
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Lloyd MK, Stein RA, Ibarra DE, Barclay RS, Wing SL, Stahle DW, Dawson TE, Stolper DA. Isotopic clumping in wood as a proxy for photorespiration in trees. Proc Natl Acad Sci U S A 2023; 120:e2306736120. [PMID: 37931112 PMCID: PMC10655223 DOI: 10.1073/pnas.2306736120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 09/22/2023] [Indexed: 11/08/2023] Open
Abstract
Photorespiration can limit gross primary productivity in terrestrial plants. The rate of photorespiration relative to carbon fixation increases with temperature and decreases with atmospheric [CO2]. However, the extent to which this rate varies in the environment is unclear. Here, we introduce a proxy for relative photorespiration rate based on the clumped isotopic composition of methoxyl groups (R-O-CH3) in wood. Most methoxyl C-H bonds are formed either during photorespiration or the Calvin cycle and thus their isotopic composition may be sensitive to the mixing ratio of these pathways. In water-replete growing conditions, we find that the abundance of the clumped isotopologue 13CH2D correlates with temperature (18-28 °C) and atmospheric [CO2] (280-1000 ppm), consistent with a common dependence on relative photorespiration rate. When applied to a global dataset of wood, we observe global trends of isotopic clumping with climate and water availability. Clumped isotopic compositions are similar across environments with temperatures below ~18 °C. Above ~18 °C, clumped isotopic compositions in water-limited and water-replete trees increasingly diverge. We propose that trees from hotter climates photorespire substantially more than trees from cooler climates. How increased photorespiration is managed depends on water availability: water-replete trees export more photorespiratory metabolites to lignin whereas water-limited trees either export fewer overall or direct more to other sinks that mitigate water stress. These disparate trends indicate contrasting responses of photorespiration rate (and thus gross primary productivity) to a future high-[CO2] world. This work enables reconstructing photorespiration rates in the geologic past using fossil wood.
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Affiliation(s)
- Max K. Lloyd
- Department of Earth and Planetary Science, University of California, Berkeley, CA94720
- Department of Geosciences, The Pennsylvania State University, University Park, PA16802
| | - Rebekah A. Stein
- Department of Earth and Planetary Science, University of California, Berkeley, CA94720
- Department of Chemistry and Physical Sciences, Quinnipiac University, Hamden, CT06518
| | - Daniel E. Ibarra
- Department of Earth and Planetary Science, University of California, Berkeley, CA94720
- Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, RI02912
| | - Richard S. Barclay
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC20560
| | - Scott L. Wing
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC20560
| | - David W. Stahle
- Department of Geosciences, University of Arkansas, Fayetteville, AR72701
| | - Todd E. Dawson
- Department of Integrative Biology, University of California, Berkeley, CA94720
| | - Daniel A. Stolper
- Department of Earth and Planetary Science, University of California, Berkeley, CA94720
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7
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Meng X, Bai S, Wang S, Pan Y, Chen K, Xie K, Wang M, Guo S. The sensitivity of photosynthesis to magnesium deficiency differs between rice ( Oryza sativa L.) and cucumber ( Cucumis sativus L.). FRONTIERS IN PLANT SCIENCE 2023; 14:1164866. [PMID: 37123833 PMCID: PMC10141327 DOI: 10.3389/fpls.2023.1164866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 03/27/2023] [Indexed: 05/03/2023]
Abstract
Magnesium is an essential macronutrient for plant photosynthesis, and in response to Mg deficiency, dicots appear more sensitive than monocots. Under Mg deficiency, we investigated the causes of differing photosynthetic sensitivities in a dicot and a monocot species. Rice (Oryza sativa L.) and cucumber (Cucumis sativus L.) were grown in hydroponic culture to explore their physiological responses to Mg deficiency stress. Both Mg-deficient rice and cucumber plants exhibited lower biomass, leaf area, Mg concentration, and chlorophyll content (Chl) compared with Mg-sufficient plants. However, a more marked decline in Chl and carotenoid content (Car) occurred in cucumber. A lower CO2 concentration in chloroplasts (C c) was accompanied by a decrease in the maximum rate of electron transport (J max) and the maximum rate of ribulose 1,5-bisphosphate carboxylation (V cmax), restricting CO2 utilization in Mg-deficient plants. Rice and cucumber photorespiration rate (P r) increased under Mg deficiency. Additionally, for cucumber, Car and non-photochemical quenching (NPQ) were reduced under lower Mg supply. Meanwhile, cucumber Mg deficiency significantly increased the fraction of absorbed light energy dissipated by an additional quenching mechanism (Φf,D). Under Mg deficiency, suppressed photosynthesis was attributed to comprehensive restrictions of mesophyll conductance (g m), J max, and V cmax. Cucumber was more sensitive to Mg deficiency than rice due to lower NPQ, higher rates of electron transport to alternative pathways, and subsequently, photooxidation damage.
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Affiliation(s)
- Xusheng Meng
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Song Bai
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Shiyu Wang
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Yonghui Pan
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Kehao Chen
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Kailiu Xie
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
- School of Land Resources and Environment, Jiangxi Agricultural University, Nanchang, China
| | - Min Wang
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
| | - Shiwei Guo
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, China
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8
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Sharkey TD. The discovery of rubisco. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:510-519. [PMID: 35689795 DOI: 10.1093/jxb/erac254] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/09/2022] [Indexed: 06/15/2023]
Abstract
Rubisco is possibly the most important enzyme on Earth, certainly in terms of amount. This review describes the initial reports of ribulose 1,5-bisphosphate carboxylating activity. Discoveries of core concepts are described, including its quaternary structure, the requirement for post-translational modification, and its role as an oxygenase as well as a carboxylase. Finally, the requirement for numerous chaperonins for assembly of rubisco in plants is described.
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Affiliation(s)
- Thomas D Sharkey
- MSU-DOE Plant Research Laboratory, Plant Resilience Institute, and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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9
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Mulero G, Jiang D, Bonfil DJ, Helman D. Use of thermal imaging and the photochemical reflectance index (PRI) to detect wheat response to elevated CO 2 and drought. PLANT, CELL & ENVIRONMENT 2023; 46:76-92. [PMID: 36289576 PMCID: PMC10098568 DOI: 10.1111/pce.14472] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 09/05/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
The spectral-based photochemical reflectance index (PRI) and leaf surface temperature (Tleaf ) derived from thermal imaging are two indicative metrics of plant functioning. The relationship of PRI with radiation-use efficiency (RUE) and Tleaf with leaf transpiration could be leveraged to monitor crop photosynthesis and water use from space. Yet, it is unclear how such relationships will change under future high carbon dioxide concentrations ([CO2 ]) and drought. Here we established an [CO2 ] enrichment experiment in which three wheat genotypes were grown at ambient (400 ppm) and elevated (550 ppm) [CO2 ] and exposed to well-watered and drought conditions in two glasshouse rooms in two replicates. Leaf transpiration (Tr ) and latent heat flux (LE) were derived to assess evaporative cooling, and RUE was calculated from assimilation and radiation measurements on several dates along the season. Simultaneous hyperspectral and thermal images were taken at~ $\unicode{x0007E}$ 1.5 m from the plants to derive PRI and the temperature difference between the leaf and its surrounding air (∆ $\unicode{x02206}$ Tleaf-air ). We found significant PRI and RUE and∆ $\unicode{x02206}$ Tleaf-air and Tr correlations, with no significant differences among the genotypes. A PRI-RUE decoupling was observed under drought at ambient [CO2 ] but not at elevated [CO2 ], likely due to changes in photorespiration. For a LE range of 350 W m-2 , the ΔTleaf-air range was~ $\unicode{x0007E}$ 10°C at ambient [CO2 ] and only~ $\unicode{x0007E}$ 4°C at elevated [CO2 ]. Thicker leaves in plants grown at elevated [CO2 ] suggest higher leaf water content and consequently more efficient thermoregulation at high [CO2 ] conditions. In general, Tleaf was maintained closer to the ambient temperature at elevated [CO2 ], even under drought. PRI, RUE, ΔTleaf -air , and Tr decreased linearly with canopy depth, displaying a single PRI-RUE and ΔTleaf -air Tr model through the canopy layers. Our study shows the utility of these sensing metrics in detecting wheat responses to future environmental changes.
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Affiliation(s)
- Gabriel Mulero
- Department of Soil & Water Sciences, Institute of Environmental Sciences, The Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of JerusalemRehovotIsrael
| | - Duo Jiang
- Department of Soil & Water Sciences, Institute of Environmental Sciences, The Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of JerusalemRehovotIsrael
| | - David J. Bonfil
- Department of Vegetable and Field Crop ResearchAgricultural Research Organization, Gilat Research CenterGilatIsrael
| | - David Helman
- Department of Soil & Water Sciences, Institute of Environmental Sciences, The Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of JerusalemRehovotIsrael
- The Advanced School for Environmental StudiesThe Hebrew University of JerusalemJerusalemIsrael
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10
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Bergman ME, Evans SE, Davis B, Hamid R, Bajwa I, Jayathilake A, Chahal AK, Phillips MA. An Arabidopsis GCMS chemical ionization technique to quantify adaptive responses in central metabolism. PLANT PHYSIOLOGY 2022; 189:2072-2090. [PMID: 35512197 PMCID: PMC9342981 DOI: 10.1093/plphys/kiac207] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 04/05/2022] [Indexed: 05/06/2023]
Abstract
We present a methodology to survey central metabolism in 13CO2-labeled Arabidopsis (Arabidopsis thaliana) rosettes by ammonia positive chemical ionization-gas chromatography-mass spectrometry. This technique preserves the molecular ion cluster of methyloxime/trimethylsilyl-derivatized analytes up to 1 kDa, providing unambiguous nominal mass assignment of >200 central metabolites and 13C incorporation rates into a subset of 111 from the tricarboxylic acid (TCA) cycle, photorespiratory pathway, amino acid metabolism, shikimate pathway, and lipid and sugar metabolism. In short-term labeling assays, we observed plateau labeling of ∼35% for intermediates of the photorespiratory cycle except for glyoxylate, which reached only ∼4% labeling and was also present at molar concentrations several fold lower than other photorespiratory intermediates. This suggests photorespiratory flux may involve alternate intermediate pools besides the generally accepted route through glyoxylate. Untargeted scans showed that in illuminated leaves, noncyclic TCA cycle flux and citrate export to the cytosol revert to a cyclic flux mode following methyl jasmonate (MJ) treatment. MJ also caused a block in the photorespiratory transamination of glyoxylate to glycine. Salicylic acid treatment induced the opposite effects in both cases, indicating the antagonistic relationship of these defense signaling hormones is preserved at the metabolome level. We provide complete chemical ionization spectra for 203 Arabidopsis metabolites from central metabolism, which uniformly feature the unfragmented pseudomolecular ion as the base peak. This unbiased, soft ionization technique is a powerful screening tool to identify adaptive metabolic trends in photosynthetic tissue and represents an important advance in methodology to measure plant metabolic flux.
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Affiliation(s)
- Matthew E Bergman
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada M5S 3G5
| | - Sonia E Evans
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada M5S 3G5
| | - Benjamin Davis
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada M5S 3G5
| | - Rehma Hamid
- Department of Biology, University of Toronto—Mississauga, Mississauga, Ontario, Canada L5L 1C6
| | - Ibadat Bajwa
- Department of Biology, University of Toronto—Mississauga, Mississauga, Ontario, Canada L5L 1C6
| | - Amreetha Jayathilake
- Department of Biology, University of Toronto—Mississauga, Mississauga, Ontario, Canada L5L 1C6
| | - Anmol Kaur Chahal
- Department of Biology, University of Toronto—Mississauga, Mississauga, Ontario, Canada L5L 1C6
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11
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Reimport of carbon from cytosolic and vacuolar sugar pools into the Calvin-Benson cycle explains photosynthesis labeling anomalies. Proc Natl Acad Sci U S A 2022; 119:e2121531119. [PMID: 35259011 PMCID: PMC8931376 DOI: 10.1073/pnas.2121531119] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SignificancePhotosynthesis metabolites are quickly labeled when 13CO2 is fed to leaves, but the time course of labeling reveals additional contributing processes involved in the metabolic dynamics of photosynthesis. The existence of three such processes is demonstrated, and a metabolic flux model is developed to explore and characterize them. The model is consistent with a slow return of carbon from cytosolic and vacuolar sugars into the Calvin-Benson cycle through the oxidative pentose phosphate pathway. Our results provide insight into how carbon assimilation is integrated into the metabolic network of photosynthetic cells with implications for global carbon fluxes.
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12
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Basu D, South PF. Design and Analysis of Native Photorespiration Gene Motifs of Promoter Untranslated Region Combinations Under Short Term Abiotic Stress Conditions. FRONTIERS IN PLANT SCIENCE 2022; 13:828729. [PMID: 35251099 PMCID: PMC8888687 DOI: 10.3389/fpls.2022.828729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 01/18/2022] [Indexed: 05/09/2023]
Abstract
Quantitative traits are rarely controlled by a single gene, thereby making multi-gene transformation an indispensable component of modern synthetic biology approaches. However, the shortage of unique gene regulatory elements (GREs) for the robust simultaneous expression of multiple nuclear transgenes is a major bottleneck that impedes the engineering of complex pathways in plants. In this study, we compared the transcriptional efficacies of a comprehensive list of well-documented promoter and untranslated region (UTR) sequences side by side. The strength of GREs was examined by a dual-luciferase assay in conjunction with transient expression in tobacco. In addition, we created suites of new GREs with higher transcriptional efficacies by combining the best performing promoter-UTR sequences. We also tested the impact of elevated temperature and high irradiance on the effectiveness of these GREs. While constitutive promoters ensure robust expression of transgenes, they lack spatiotemporal regulations exhibited by native promoters. Here, we present a proof-of-principle study on the characterization of synthetic promoters based on cis-regulatory elements of three key photorespiratory genes. This conserved biochemical process normally increases under elevated temperature, low CO2, and high irradiance stress conditions and results in ∼25% loss in fixed CO2. To select stress-responsive cis-regulatory elements involved in photorespiration, we analyzed promoters of two chloroplast transporters (AtPLGG1 and AtBASS6) and a key plastidial enzyme, AtPGLP using PlantPAN3.0 and AthaMap. Our results suggest that these motifs play a critical role for PLGG1, BASS6, and PGLP in mediating response to elevated temperature and high-intensity light stress. These findings will not only enable the advancement of metabolic and genetic engineering of photorespiration but will also be instrumental in related synthetic biology approaches.
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Affiliation(s)
| | - Paul F. South
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States
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13
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Nayak L, Panda D, Dash GK, Lal MK, Swain P, Baig MJ, Kumar A. A chloroplast Glycolate catabolic pathway bypassing the endogenous photorespiratory cycle enhances photosynthesis, biomass and yield in rice (Oryza sativa L.). PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 314:111103. [PMID: 34895540 DOI: 10.1016/j.plantsci.2021.111103] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/27/2021] [Accepted: 10/27/2021] [Indexed: 05/21/2023]
Abstract
Photorespiration accounts for 20-50 % reduction in grain yield in C3 crops. The process is essential to remove 2-phosphoglycolate produced due to the oxygenation activity of the ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCO) enzyme. Attempts were made to improve photosynthesis through enriched CO2 concentration by installing numerous photorespiratory bypass modules in the chloroplast of several crops. In this study, we have introduced Escherichia coli glycolate catabolic pathway (ECGC) into rice chloroplast to bypass photorespiration partially (PB) or completely (FB). Five genes encoding glyoxylate carboligase (GCL), tartronic semialdehyde reductase (TSR), and three subunits of glycolate dehydrogenase (GDH) were introduced to get FB plants, whereas only the three subunits of GDH were introduced to get PB plants. Southern analysis confirmed stable integration of the transgenes and their expression was confirmed by RT-qPCR analysis in the T3 progenies. Both FB and PB transformed lines exhibited increased photosynthetic efficiency, biomass, and grain yield than wild type (WT) with empty vector control. The introduction of ECGC pathway favoured the carboxylase activity of RuBisCO while decreasing its oxygenase activity fostering the functioning of Calvin-Benson cycle and resulting in an increased carbon-assimilation that was manifested in their superior architecture and harvest index. These findings will support rice and related cereal crop breeding programs to increase yield under elevated temperature and arid conditions.
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Affiliation(s)
- Lopamudra Nayak
- Division of Crop Physiology and Biochemistry, ICAR- National Rice Research Institute (ICAR-NRRI), Cuttack, 753006, Odisha, India
| | - Darshan Panda
- Division of Crop Physiology and Biochemistry, ICAR- National Rice Research Institute (ICAR-NRRI), Cuttack, 753006, Odisha, India
| | - Goutam Kumar Dash
- Division of Crop Physiology and Biochemistry, ICAR- National Rice Research Institute (ICAR-NRRI), Cuttack, 753006, Odisha, India
| | - Milan Kumar Lal
- Division of Crop Physiology, Biochemistry and Post-Harvest Technology, ICAR-Central Potato Research Insititute (ICAR-CPRI), Shimla, 171001, Himachal Pradesh, India
| | - Padmini Swain
- Division of Crop Physiology and Biochemistry, ICAR- National Rice Research Institute (ICAR-NRRI), Cuttack, 753006, Odisha, India
| | - M J Baig
- Division of Crop Physiology and Biochemistry, ICAR- National Rice Research Institute (ICAR-NRRI), Cuttack, 753006, Odisha, India.
| | - Awadhesh Kumar
- Division of Crop Physiology and Biochemistry, ICAR- National Rice Research Institute (ICAR-NRRI), Cuttack, 753006, Odisha, India.
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14
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Sun Y, Li Y, Li Y, Wang M, Mur LAJ, Shen Q, Guo S. Nitrate mediated resistance against Fusarium infection in cucumber plants acts via photorespiration. PLANT, CELL & ENVIRONMENT 2021; 44:3412-3431. [PMID: 34181268 DOI: 10.1111/pce.14140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 06/20/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
Fusarium wilt is one of the major biotic factors limiting cucumber (Cucumis sativus L.) growth and yield. The outcomes of cucumber-Fusarium interactions can be influenced by the form of nitrogen nutrition (nitrate [NO3- ] or ammonium [NH4+ ]); however, the physiological mechanisms of N-regulated cucumber disease resistance are still largely unclear. Here, we investigated the relationship between nitrogen forms and cucumber resistance to Fusarium infection. Our results showed that on Fusarium infection, NO3- feeding decreased the levels of the fungal toxin, fusaric acid, leaf membrane oxidative, organelle damage and disease-associated loss in photosynthesis. Metabolomic analysis and gas-exchange measurements linked NO3- mediated plant defence with enhanced leaf photorespiration rates. Cucumber plants sprayed with the photorespiration inhibitor isoniazid were more susceptible to Fusarium and there was a negative correlation between photorespiration rate and leaf membrane injury. However, there were positive correlations between photorespiration rate, NO3- assimilation and the tricarboxylic acid (TCA) cycle. This provides a potential electron sink or the peroxisomal H2 O2 catalysed by glycolate oxidase. We suggest that the NO3- nutrition enhanced cucumber resistance against Fusarium infection was associated with photorespiration. Our findings provide a novel insight into a mechanism involving the interaction of photorespiration with nitrogen forms to drive wider defence.
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Affiliation(s)
- Yuming Sun
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Centre for Organic-based Fertilizers, Jiangsu Collaborative Innovation Centre for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, China
- Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, China
| | - Yingrui Li
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Centre for Organic-based Fertilizers, Jiangsu Collaborative Innovation Centre for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, China
| | - Yong Li
- Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Min Wang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Centre for Organic-based Fertilizers, Jiangsu Collaborative Innovation Centre for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, China
| | - Luis Alejandro Jose Mur
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, UK
| | - Qirong Shen
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Centre for Organic-based Fertilizers, Jiangsu Collaborative Innovation Centre for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, China
| | - Shiwei Guo
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Centre for Organic-based Fertilizers, Jiangsu Collaborative Innovation Centre for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, China
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15
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Wieloch T. The next phase in the development of 13C isotopically non-stationary metabolic flux analysis. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:6087-6090. [PMID: 34131712 PMCID: PMC8483781 DOI: 10.1093/jxb/erab292] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
This viewpoint devises recommendations for future studies utilizing 13C isotopically non-stationary metabolic flux analysis to characterize plant metabolism. Most importantly, it highlights the necessity for model validation.
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Affiliation(s)
- Thomas Wieloch
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
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16
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Abstract
Photorespiration results in a large amount of leaf photosynthesis consumption. However, there are few studies on the response of photorespiration to multi-factors. In this study, a machine learning model for the photorespiration rate of cucumber leaves’ response to multi-factors was established. It provides a theoretical basis for studies related to photorespiration. Machine learning models of different methods were designed and compared. The photorespiration rate was expressed as the difference between the photosynthetic rate at 2% O2 and 21% O2 concentrations. The results show that the XGBoost models had the best fit performance with an explained variance score of 0.970 for both photosynthetic rate datasets measured using air and 2% O2, with mean absolute errors of 0.327 and 0.181, root mean square errors of 1.607 and 1.469, respectively, and coefficients of determination of 0.970 for both. In addition, this study indicates the importance of the features of temperature, humidity and the physiological status of the leaves for predicted results of photorespiration. The model established in this study performed well, with high accuracy and generalization ability. As a preferable exploration of the research on photorespiration rate simulation, it has theoretical significance and application prospects.
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17
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Osei-Bonsu I, McClain AM, Walker BJ, Sharkey TD, Kramer DM. The roles of photorespiration and alternative electron acceptors in the responses of photosynthesis to elevated temperatures in cowpea. PLANT, CELL & ENVIRONMENT 2021; 44:2290-2307. [PMID: 33555066 PMCID: PMC11176259 DOI: 10.1111/pce.14026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 11/13/2020] [Accepted: 11/20/2020] [Indexed: 05/02/2023]
Abstract
We explored the effects, on photosynthesis in cowpea (Vigna unguiculata) seedlings, of high temperature and light-environmental stresses that often co-occur under field conditions and can have greater impact on photosynthesis than either by itself. We observed contrasting responses in the light and carbon assimilatory reactions, whereby in high temperature, the light reactions were stimulated while CO2 assimilation was substantially reduced. There were two striking observations. Firstly, the primary quinone acceptor (QA ), a measure of the regulatory balance of the light reactions, became more oxidized with increasing temperature, suggesting increased electron sink capacity, despite the reduced CO2 fixation. Secondly, a strong, O2 -dependent inactivation of assimilation capacity, consistent with down-regulation of rubisco under these conditions. The dependence of these effects on CO2 , O2 and light led us to conclude that both photorespiration and an alternative electron acceptor supported increased electron flow, and thus provided photoprotection under these conditions. Further experiments showed that the increased electron flow was maintained by rapid rates of PSII repair, particularly at combined high light and temperature. Overall, the results suggest that photodamage to the light reactions can be avoided under high light and temperatures by increasing electron sink strength, even when assimilation is strongly suppressed.
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Affiliation(s)
- Isaac Osei-Bonsu
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Horticulture Division, CSIR-Crops Research Institute, Kumasi, Ghana
| | - Alan M McClain
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Berkley J Walker
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
| | - Thomas D Sharkey
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - David M Kramer
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
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18
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Photorespiration: The Futile Cycle? PLANTS 2021; 10:plants10050908. [PMID: 34062784 PMCID: PMC8147352 DOI: 10.3390/plants10050908] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 04/29/2021] [Accepted: 04/29/2021] [Indexed: 12/03/2022]
Abstract
Photorespiration, or C2 photosynthesis, is generally considered a futile cycle that potentially decreases photosynthetic carbon fixation by more than 25%. Nonetheless, many essential processes, such as nitrogen assimilation, C1 metabolism, and sulfur assimilation, depend on photorespiration. Most studies of photosynthetic and photorespiratory reactions are conducted with magnesium as the sole metal cofactor despite many of the enzymes involved in these reactions readily associating with manganese. Indeed, when manganese is present, the energy efficiency of these reactions may improve. This review summarizes some commonly used methods to quantify photorespiration, outlines the influence of metal cofactors on photorespiratory enzymes, and discusses why photorespiration may not be as wasteful as previously believed.
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19
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Schiestl‐Aalto P, Stangl ZR, Tarvainen L, Wallin G, Marshall J, Mäkelä A. Linking canopy-scale mesophyll conductance and phloem sugar δ 13 C using empirical and modelling approaches. THE NEW PHYTOLOGIST 2021; 229:3141-3155. [PMID: 33222199 PMCID: PMC7986199 DOI: 10.1111/nph.17094] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 11/16/2020] [Indexed: 05/26/2023]
Abstract
Interpreting phloem carbohydrate or xylem tissue carbon isotopic composition as measures of water-use efficiency or past tree productivity requires in-depth knowledge of the factors altering the isotopic composition within the pathway from ambient air to phloem contents and tree ring. One of least understood of these factors is mesophyll conductance (gm ). We formulated a dynamic model describing the leaf photosynthetic pathway including seven alternative gm descriptions and a simple transport of sugars from foliage down the trunk. We parameterised the model for a boreal Scots pine stand and compared simulated gm responses with weather variations. We further compared the simulated δ13 C of new photosynthates among the different gm descriptions and against measured phloem sugar δ13 C. Simulated gm estimates of the seven descriptions varied according to weather conditions, resulting in varying estimates of phloem δ13 C during cold/moist and warm/dry periods. The model succeeded in predicting a drought response and a postdrought release in phloem sugar δ13 C indicating suitability of the model for inverse prediction of leaf processes from phloem isotopic composition. We suggest short-interval phloem sampling during and after extreme weather conditions to distinguish between mesophyll conductance drivers for future model development.
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Affiliation(s)
- Pauliina Schiestl‐Aalto
- Institute for Atmospheric and Earth System Research (INAR)/Forest SciencesHelsinki00014Finland
- Department of Forest Ecology and ManagementSLUUmeå901 83Sweden
| | | | - Lasse Tarvainen
- Department of Biological and Environmental SciencesUniversity of GothenburgGothenburg405 30Sweden
| | - Göran Wallin
- Department of Biological and Environmental SciencesUniversity of GothenburgGothenburg405 30Sweden
| | - John Marshall
- Department of Forest Ecology and ManagementSLUUmeå901 83Sweden
| | - Annikki Mäkelä
- Institute for Atmospheric and Earth System Research (INAR)/Forest SciencesHelsinki00014Finland
- Department of Forest Ecology and ManagementSLUUmeå901 83Sweden
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20
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13C Isotope Labelling to Follow the Flux of Photorespiratory Intermediates. PLANTS 2021; 10:plants10030427. [PMID: 33668274 PMCID: PMC7996249 DOI: 10.3390/plants10030427] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 02/18/2021] [Accepted: 02/19/2021] [Indexed: 12/04/2022]
Abstract
Measuring the carbon flux through metabolic pathways in intact illuminated leaves remains challenging because of, e.g., isotopic dilution by endogenous metabolites, the impossibility to reach isotopic steady state, and the occurrence of multiple pools. In the case of photorespiratory intermediates, our knowledge of the partitioning between photorespiratory recycling, storage, and utilization by other pathways is thus rather limited. There has been some controversy as to whether photorespiratory glycine and serine may not be recycled, thus changing the apparent stoichiometric coefficient between photorespiratory O2 fixation and CO2 release. We describe here an isotopic method to trace the fates of glycine, serine and glycerate, taking advantage of positional 13C content with NMR and isotopic analyses by LC–MS. This technique is well-adapted to show that the proportion of glycerate, serine and glycine molecules escaping photorespiratory recycling is very small.
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21
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刘 爽. Response of C<sub>3</sub> Plants Leaf Enzymes to Nitrogen Addition. INTERNATIONAL JOURNAL OF ECOLOGY 2021. [DOI: 10.12677/ije.2021.102038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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22
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Emerging research in plant photosynthesis. Emerg Top Life Sci 2020; 4:137-150. [PMID: 32573736 DOI: 10.1042/etls20200035] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/03/2020] [Accepted: 06/05/2020] [Indexed: 12/27/2022]
Abstract
Photosynthesis involves capturing light energy and, most often, converting it to chemical energy stored as reduced carbon. It is the source of food, fuel, and fiber and there is a resurgent interest in basic research on photosynthesis. Plants make excellent use of visible light energy; leaves are ideally suited to optimize light use by having a large area per amount of material invested and also having leaf angles to optimize light utilization. It is thought that plants do not use green light but in fact they use green light better than blue light under some conditions. Leaves also have mechanisms to protect against excess light and how these work in a stochastic light environment is currently a very active area of current research. The speed at which photosynthesis can begin when leaves are first exposed to light and the speed of induction of protective mechanisms, as well as the speed at which protective mechanisms dissipate when light levels decline, have recently been explored. Research is also focused on reducing wasteful processes such as photorespiration, when oxygen instead of carbon dioxide is used. Some success has been reported in altering the path of carbon in photorespiration but on closer inspection there appears to be unforeseen effects contributing to the good news. The stoichiometry of interaction of light reactions with carbon metabolism is rigid and the time constants vary tremendously presenting large challenges to regulatory mechanisms. Regulatory mechanisms will be the topic of photosynthesis research for some time to come.
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23
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Busch FA. Photorespiration in the context of Rubisco biochemistry, CO 2 diffusion and metabolism. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:919-939. [PMID: 31910295 DOI: 10.1111/tpj.14674] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 12/20/2019] [Accepted: 01/03/2020] [Indexed: 05/11/2023]
Abstract
Photorespiratory metabolism is essential for plants to maintain functional photosynthesis in an oxygen-containing environment. Because the oxygenation reaction of Rubisco is followed by the loss of previously fixed carbon, photorespiration is often considered a wasteful process and considerable efforts are aimed at minimizing the negative impact of photorespiration on the plant's carbon uptake. However, the photorespiratory pathway has also many positive aspects, as it is well integrated within other metabolic processes, such as nitrogen assimilation and C1 metabolism, and it is important for maintaining the redox balance of the plant. The overall effect of photorespiratory carbon loss on the net CO2 fixation of the plant is also strongly influenced by the physiology of the leaf related to CO2 diffusion. This review outlines the distinction between Rubisco oxygenation and photorespiratory CO2 release as a basis to evaluate the costs and benefits of photorespiration.
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Affiliation(s)
- Florian A Busch
- Research School of Biology and ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Acton, ACT, 2601, Australia
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24
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Simkin AJ. Genetic Engineering for Global Food Security: Photosynthesis and Biofortification. PLANTS (BASEL, SWITZERLAND) 2019; 8:E586. [PMID: 31835394 PMCID: PMC6963231 DOI: 10.3390/plants8120586] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 12/04/2019] [Accepted: 12/05/2019] [Indexed: 12/18/2022]
Abstract
Increasing demands for food and resources are challenging existing markets, driving a need to continually investigate and establish crop varieties with improved yields and health benefits. By the later part of the century, current estimates indicate that a >50% increase in the yield of most of the important food crops including wheat, rice and barley will be needed to maintain food supplies and improve nutritional quality to tackle what has become known as 'hidden hunger'. Improving the nutritional quality of crops has become a target for providing the micronutrients required in remote communities where dietary variation is often limited. A number of methods to achieve this have been investigated over recent years, from improving photosynthesis through genetic engineering, to breeding new higher yielding varieties. Recent research has shown that growing plants under elevated [CO2] can lead to an increase in Vitamin C due to changes in gene expression, demonstrating one potential route for plant biofortification. In this review, we discuss the current research being undertaken to improve photosynthesis and biofortify key crops to secure future food supplies and the potential links between improved photosynthesis and nutritional quality.
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Affiliation(s)
- Andrew John Simkin
- Genetics, Genomics and Breeding, NIAB EMR, East Malling, Kent, ME19 6BJ, UK
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25
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Ye ZP, Liu YG, Kang HJ, Duan HL, Chen XM, Zhou SX. Comparing two measures of leaf photorespiration rate across a wide range of light intensities. JOURNAL OF PLANT PHYSIOLOGY 2019; 240:153002. [PMID: 31254740 DOI: 10.1016/j.jplph.2019.153002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 06/17/2019] [Accepted: 06/17/2019] [Indexed: 06/09/2023]
Abstract
Suppression of photorespiration by low O2 concentrations (Method 1) and simultaneous measurements of gas exchange and chlorophyll fluorescence (Method 2) are often used to estimate leaf photorespiration rate (Rp) of C3 plants. However, it is largely unknown whether Method 1 and Method 2 can be used equivalently in estimating Rp. Using a field experiment on two wheat cultivars (T. aestivum JM22 and T. aestivum Z39-118) whose leaf gas exchange and chlorophyll fluorescence at low and normal O2 concentrations (2% versus 21% O2) were simultaneously measured across a wide range of light intensities (I), this study assessed the impacts of the two measures on Rp and its response under changing irradiance conditions. All the above quantities increased with the increasing I until reaching the cultivar-specific maximum values and the corresponding saturation light intensities. However, there were significant differences between Rp estimated by Method 1 and Method 2 at the I range from 150 to 2000 μmol m-2 s-1 for T. aestivum JM22 and from 150 to 1000 μmol m-2 s-1 for T. aestivum Z39-118. These findings demonstrated that the two methods cannot be used equivalently under changing irradiance conditions.
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Affiliation(s)
- Zi-Piao Ye
- Maths and Physics College, Jinggangshan University, Ji'an 343009, Jiangxi, China
| | - Yu-Guo Liu
- Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China
| | - Hua-Jing Kang
- Wenzhou Vocational College of Science and Technology, Wenzhou 325006, Zhejiang, China
| | - Hong-Lang Duan
- Jiangxi Provincial Key Laboratory for Restoration of Degraded Ecosystems & Watershed Ecohydrology, Nanchang Institute of Technology, Nanchang 330099, China
| | - Xian-Mao Chen
- Soil Fertilizer and Environmental Resources Institute, Jiangxi Academy of Agricultural Sciences, Nanchang 330200, Jiangxi, China.
| | - Shuang-Xi Zhou
- The New Zealand Institute for Plant and Food Research Limited, Hawke's Bay 4130, New Zealand.
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26
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Knebl A, Domes R, Yan D, Popp J, Trumbore S, Frosch T. Fiber-Enhanced Raman Gas Spectroscopy for 18O- 13C-Labeling Experiments. Anal Chem 2019; 91:7562-7569. [PMID: 31050402 DOI: 10.1021/acs.analchem.8b05684] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Stable isotopes are used in ecology to track and disentangle different processes and pathways. Especially for studies focused on the gas exchange of plants, sensing techniques that offer oxygen (O2) and carbon dioxide (CO2) sensitivity with isotopic discrimination are highly sought after. Addressing this challenge, fiber-enhanced Raman gas spectroscopy is introduced as a fast optical technique directly combining 13CO2 and 12CO2 as well as 18O2 and 16O2 measurements in one instrument. We demonstrate how a new type of optical hollow-core fiber, the so-called revolver fiber, is utilized for enhanced Raman gas sensing. Carbon dioxide and oxygen isotopologues were measured at concentrations expected when using 13C- and 18O-labeled gases in plant experiments. Limits of detection have been determined to be 25 ppm for CO2 and 150 ppm for O2. The combination of measurements with different integration times allows the creation of highly resolved broadband spectra. With the help of calculations based on density functional theory, the line at 1512 cm-1 occurring in the oxygen spectrum is assigned to 18O16O. The relative abundances of the isotopologues 18O16O and nitrogen 15N14N were in good agreement with typical values. For CO2, fiber-enhanced Raman spectra show the Fermi diad and hotbands of 12C16O2, 13C16O2, and 12C18O16O. Several weak lines were observed, and the line at 1426 cm-1 was identified as originating from the (0 4 0 2) → (0 2 0 2) transition of 12C16O2. With the demonstrated sensitivity and discriminatory power, fiber-enhanced Raman spectroscopy is a possible alternative means to investigate plant metabolism, directly combining 13CO2 and 12CO2 measurements with 18O2 and 16O2 measurements in one instrument. The presented method thus has large potential for basic analytical investigations as well as for applications in the environmental sciences.
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Affiliation(s)
- Andreas Knebl
- Leibniz Institute of Photonic Technology , 07745 Jena , Germany.,Max-Planck-Institute for Biogeochemistry , 07745 Jena , Germany
| | - Robert Domes
- Leibniz Institute of Photonic Technology , 07745 Jena , Germany
| | - Di Yan
- Leibniz Institute of Photonic Technology , 07745 Jena , Germany
| | - Juergen Popp
- Leibniz Institute of Photonic Technology , 07745 Jena , Germany.,Institute of Physical Chemistry & Abbe Center of Photonics , Friedrich Schiller University , 07743 Jena , Germany
| | - Susan Trumbore
- Max-Planck-Institute for Biogeochemistry , 07745 Jena , Germany
| | - Torsten Frosch
- Leibniz Institute of Photonic Technology , 07745 Jena , Germany.,Institute of Physical Chemistry & Abbe Center of Photonics , Friedrich Schiller University , 07743 Jena , Germany
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27
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Simkin AJ, López-Calcagno PE, Raines CA. Feeding the world: improving photosynthetic efficiency for sustainable crop production. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:1119-1140. [PMID: 30772919 PMCID: PMC6395887 DOI: 10.1093/jxb/ery445] [Citation(s) in RCA: 213] [Impact Index Per Article: 42.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/27/2018] [Indexed: 05/18/2023]
Abstract
A number of recent studies have provided strong support demonstrating that improving the photosynthetic processes through genetic engineering can provide an avenue to improve yield potential. The major focus of this review is on improvement of the Calvin-Benson cycle and electron transport. Consideration is also given to how altering regulatory process may provide an additional route to increase photosynthetic efficiency. Here we summarize some of the recent successes that have been observed through genetic manipulation of photosynthesis, showing that, in both the glasshouse and the field, yield can be increased by >40%. These results provide a clear demonstration of the potential for increasing yield through improvements in photosynthesis. In the final section, we consider the need to stack improvement in photosynthetic traits with traits that target the yield gap in order to provide robust germplasm for different crops across the globe.
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Affiliation(s)
- Andrew J Simkin
- NIAB EMR, New Road, East Malling, Kent, UK
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester, UK
| | | | - Christine A Raines
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester, UK
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28
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Tomeo NJ, Rosenthal DM. Photorespiration differs among Arabidopsis thaliana ecotypes and is correlated with photosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:5191-5204. [PMID: 30053111 PMCID: PMC6184796 DOI: 10.1093/jxb/ery274] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 07/16/2018] [Indexed: 05/19/2023]
Abstract
A greater understanding of natural variation in photosynthesis will inform strategies for crop improvement by revealing overlooked opportunities. We use Arabidopsis thaliana ecotypes as a model system to assess (i) how photosynthesis and photorespiration covary and (ii) how mesophyll conductance influences water use efficiency (WUE). Phenotypic variation in photorespiratory CO2 efflux was correlated with assimilation rates and two metrics of photosynthetic capacity (i.e. VCmax and Jmax); however, genetic correlations were not detected between photosynthesis and photorespiration. We found standing genetic variation-as broad-sense heritability-for most photosynthetic traits, including photorespiration. Genetic correlation between photosynthetic electron transport and carboxylation capacities indicates that these traits are genetically constrained. Winter ecotypes had greater mesophyll conductance, maximum carboxylation capacity, maximum electron transport capacity, and leaf structural robustness when compared with spring ecotypes. Stomatal conductance varied little in winter ecotypes, leading to a positive correlation between integrated WUE and mesophyll conductance. Thus, variation in mesophyll conductance can modulate WUE among A. thaliana ecotypes without a significant loss in assimilation. Genetic correlations between traits supplying energy and carbon to the Calvin-Benson cycle are consistent with biochemical models, suggesting that selection on either of these traits would improve all of them. Similarly, the lack of a genetic correlation between photosynthesis and photorespiration suggests that the positive scaling of these two traits can be broken.
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Affiliation(s)
- Nicholas J Tomeo
- Ohio University, Department of Environmental and Plant Biology, Athens, OH, USA
| | - David M Rosenthal
- Ohio University, Department of Environmental and Plant Biology, Athens, OH, USA
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29
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Bar-Even A. Daring metabolic designs for enhanced plant carbon fixation. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 273:71-83. [PMID: 29907311 DOI: 10.1016/j.plantsci.2017.12.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/16/2017] [Accepted: 12/16/2017] [Indexed: 05/07/2023]
Abstract
Increasing agricultural productivity is one of the major challenges our society faces. While multiple strategies to enhance plant carbon fixation have been suggested, and partially implemented, most of them are restricted to relatively simple modifications of endogenous metabolism, i.e., "low hanging fruit". Here, I portray the next generation of metabolic solutions to increase carbon fixation rate and yield. These strategies involve major rewiring of central metabolism, including dividing Rubisco's catalysis between several enzymes, replacing Rubisco with a different carboxylation reaction, substituting the Calvin Cycle with alternative carbon fixation pathways, and engineering photorespiration bypass routes that do not release carbon. While the barriers for implementing these elaborated metabolic architectures are quite significant, if we truly want to revolutionize carbon fixation, only daring engineering efforts will lead the way.
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Affiliation(s)
- Arren Bar-Even
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany.
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30
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Yu H, Li X, Duchoud F, Chuang DS, Liao JC. Augmenting the Calvin-Benson-Bassham cycle by a synthetic malyl-CoA-glycerate carbon fixation pathway. Nat Commun 2018; 9:2008. [PMID: 29789614 PMCID: PMC5964204 DOI: 10.1038/s41467-018-04417-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 04/19/2018] [Indexed: 11/21/2022] Open
Abstract
The Calvin–Benson–Bassham (CBB) cycle is presumably evolved for optimal synthesis of C3 sugars, but not for the production of C2 metabolite acetyl-CoA. The carbon loss in producing acetyl-CoA from decarboxylation of C3 sugar limits the maximum carbon yield of photosynthesis. Here we design a synthetic malyl-CoA-glycerate (MCG) pathway to augment the CBB cycle for efficient acetyl-CoA synthesis. This pathway converts a C3 metabolite to two acetyl-CoA by fixation of one additional CO2 equivalent, or assimilates glyoxylate, a photorespiration intermediate, to produce acetyl-CoA without net carbon loss. We first functionally demonstrate the design of the MCG pathway in vitro and in Escherichia coli. We then implement the pathway in a photosynthetic organism Synechococcus elongates PCC7942, and show that it increases the intracellular acetyl-CoA pool and enhances bicarbonate assimilation by roughly 2-fold. This work provides a strategy to improve carbon fixation efficiency in photosynthetic organisms. Improving carbon fixation efficiency and reducing carbon loss have been long term goals for people working on photosynthetic organism improvement. Here, the authors design a synthetic malyl-CoA-glycerate pathway for efficient acetyl-CoA synthesis and verify its function in vitro, in E. coli and in cyanobacterium.
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Affiliation(s)
- Hong Yu
- UCLA-DOE Institute of Genomics and Proteomics, 420 Westwood Plaza, Los Angeles, CA, 90095, USA.,Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Xiaoqian Li
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Fabienne Duchoud
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Derrick S Chuang
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA, 90095, USA
| | - James C Liao
- Academia Sinica, 128 Academia Road, Section 2, 115, Taipei, Taiwan.
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31
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Rodríguez-Calcerrada J, Rodrigues AM, Perdiguero P, António C, Atkin OK, Li M, Collada C, Gil L. A molecular approach to drought-induced reduction in leaf CO 2 exchange in drought-resistant Quercus ilex. PHYSIOLOGIA PLANTARUM 2018; 162:394-408. [PMID: 28984911 DOI: 10.1111/ppl.12649] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 09/20/2017] [Accepted: 10/03/2017] [Indexed: 06/07/2023]
Abstract
Drought-induced reduction of leaf gas exchange entails a complex regulation of the plant leaf metabolism. We used a combined molecular and physiological approach to understand leaf photosynthetic and respiratory responses of 2-year-old Quercus ilex seedlings to drought. Mild drought stress resulted in glucose accumulation while net photosynthetic CO2 uptake (Pn ) remained unchanged, suggesting a role of glucose in stress signaling and/or osmoregulation. Simple sugars and sugar alcohols increased throughout moderate-to-very severe drought stress conditions, in parallel to a progressive decline in Pn and the quantum efficiency of photosystem II; by contrast, minor changes occurred in respiration rates until drought stress was very severe. At very severe drought stress, 2-oxoglutarate dehydrogenase complex gene expression significantly decreased, and the abundance of most amino acids dramatically increased, especially that of proline and γ-aminobutyric acid (GABA) suggesting enhanced protection against oxidative damage and a reorganization of the tricarboxylic cycle acid cycle via the GABA shunt. Altogether, our results point to Q. ilex drought tolerance being linked to signaling and osmoregulation by hexoses during early stages of drought stress, and enhanced protection against oxidative damage by polyols and amino acids under severe drought stress.
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Affiliation(s)
- Jesús Rodríguez-Calcerrada
- Forest History, Physiology and Genetics Research Group, School of Forestry Engineering, Technical University of Madrid, Madrid 28040, Spain
| | - Ana M Rodrigues
- Plant Metabolomics Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | - Pedro Perdiguero
- Forest History, Physiology and Genetics Research Group, School of Forestry Engineering, Technical University of Madrid, Madrid 28040, Spain
- Forest Biotech Laboratory, Instituto de Biologia Experimental e Tecnológica, iBET, 2781-901 Oeiras, Portugal
| | - Carla António
- Plant Metabolomics Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | - Owen K Atkin
- ARC Centre of Excellence in Plant Energy Biology, Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, 2601, Australia
| | - Meng Li
- Forest History, Physiology and Genetics Research Group, School of Forestry Engineering, Technical University of Madrid, Madrid 28040, Spain
| | - Carmen Collada
- Forest History, Physiology and Genetics Research Group, School of Forestry Engineering, Technical University of Madrid, Madrid 28040, Spain
| | - Luis Gil
- Forest History, Physiology and Genetics Research Group, School of Forestry Engineering, Technical University of Madrid, Madrid 28040, Spain
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32
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Busch FA, Sage RF, Farquhar GD. Plants increase CO 2 uptake by assimilating nitrogen via the photorespiratory pathway. NATURE PLANTS 2018; 4:46-54. [PMID: 29229957 DOI: 10.1038/s41477-017-0065-x] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 10/27/2017] [Indexed: 05/20/2023]
Abstract
Photorespiration is a major bioengineering target for increasing crop yields as it is often considered a wasteful process. Photorespiratory metabolism is integrated into leaf metabolism and thus may have certain benefits. Here, we show that plants can increase their rate of photosynthetic CO2 uptake when assimilating nitrogen de novo via the photorespiratory pathway by fixing carbon as amino acids in addition to carbohydrates. Plants fed NO3- had higher rates of CO2 assimilation under photorespiratory than low-photorespiratory conditions, while plants lacking NO3- nutrition exhibited lower stimulation of CO2 uptake. We modified the widely used Farquhar, von Caemmerer and Berry photosynthesis model to include the carbon and electron requirements for nitrogen assimilation via the photorespiratory pathway. Our modified model improves predictions of photosynthetic CO2 uptake and of rates of photosynthetic electron transport. The results highlight how photorespiration can improve photosynthetic performance despite reducing the efficiency of Rubisco carboxylation.
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Affiliation(s)
- Florian A Busch
- Research School of Biology and ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Acton, Australian Capital Territory, Australia.
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Graham D Farquhar
- Research School of Biology and ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Acton, Australian Capital Territory, Australia
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Urban L, Aarrouf J, Bidel LPR. Assessing the Effects of Water Deficit on Photosynthesis Using Parameters Derived from Measurements of Leaf Gas Exchange and of Chlorophyll a Fluorescence. FRONTIERS IN PLANT SCIENCE 2017; 8:2068. [PMID: 29312367 PMCID: PMC5735977 DOI: 10.3389/fpls.2017.02068] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/20/2017] [Indexed: 05/21/2023]
Abstract
Water deficit (WD) is expected to increase in intensity, frequency and duration in many parts of the world as a consequence of global change, with potential negative effects on plant gas exchange and growth. We review here the parameters that can be derived from measurements made on leaves, in the field, and that can be used to assess the effects of WD on the components of plant photosynthetic rate, including stomatal conductance, mesophyll conductance, photosynthetic capacity, light absorbance, and efficiency of absorbed light conversion into photosynthetic electron transport. We also review some of the parameters related to dissipation of excess energy and to rerouting of electron fluxes. Our focus is mainly on the techniques of gas exchange measurements and of measurements of chlorophyll a fluorescence (ChlF), either alone or combined. But we put also emphasis on some of the parameters derived from analysis of the induction phase of maximal ChlF, notably because they could be used to assess damage to photosystem II. Eventually we briefly present the non-destructive methods based on the ChlF excitation ratio method which can be used to evaluate non-destructively leaf contents in anthocyanins and flavonols.
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Affiliation(s)
- Laurent Urban
- UMR 95 Qualisud/Laboratoire de Physiologie des Fruits et Légumes, Université d'Avignon, Avignon, France
| | - Jawad Aarrouf
- UMR 95 Qualisud/Laboratoire de Physiologie des Fruits et Légumes, Université d'Avignon, Avignon, France
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34
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Tcherkez G, Gauthier P, Buckley TN, Busch FA, Barbour MM, Bruhn D, Heskel MA, Gong XY, Crous KY, Griffin K, Way D, Turnbull M, Adams MA, Atkin OK, Farquhar GD, Cornic G. Leaf day respiration: low CO 2 flux but high significance for metabolism and carbon balance. THE NEW PHYTOLOGIST 2017; 216:986-1001. [PMID: 28967668 DOI: 10.1111/nph.14816] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 08/13/2017] [Indexed: 05/04/2023]
Abstract
Contents 986 I. 987 II. 987 III. 988 IV. 991 V. 992 VI. 995 VII. 997 VIII. 998 References 998 SUMMARY: It has been 75 yr since leaf respiratory metabolism in the light (day respiration) was identified as a low-flux metabolic pathway that accompanies photosynthesis. In principle, it provides carbon backbones for nitrogen assimilation and evolves CO2 and thus impacts on plant carbon and nitrogen balances. However, for a long time, uncertainties have remained as to whether techniques used to measure day respiratory efflux were valid and whether day respiration responded to environmental gaseous conditions. In the past few years, significant advances have been made using carbon isotopes, 'omics' analyses and surveys of respiration rates in mesocosms or ecosystems. There is substantial evidence that day respiration should be viewed as a highly dynamic metabolic pathway that interacts with photosynthesis and photorespiration and responds to atmospheric CO2 mole fraction. The view of leaf day respiration as a constant and/or negligible parameter of net carbon exchange is now outdated and it should now be regarded as a central actor of plant carbon-use efficiency.
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Affiliation(s)
- Guillaume Tcherkez
- Research School of Biology, College of Science, and ARC Center of Excellence for Translational Photosynthesis, Australian National University, Canberra, ACT, 2601, Australia
| | - Paul Gauthier
- Department of Geosciences, Princeton University, Princeton, NJ, 08540, USA
| | - Thomas N Buckley
- IA Watson Grains Research Centre, University of Sydney, 12656 Newell Hwy, Narrabri, NSW, 2390, Australia
| | - Florian A Busch
- Research School of Biology, College of Science, and ARC Center of Excellence for Translational Photosynthesis, Australian National University, Canberra, ACT, 2601, Australia
| | - Margaret M Barbour
- Centre for Carbon, Water and Food, University of Sydney, 380 Werombi Rd, Brownlow Hill, NSW, 2570, Australia
| | - Dan Bruhn
- Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg University, 9220, Aalborg East, Denmark
| | - Mary A Heskel
- The Ecosystems Center, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA, 02543, USA
| | - Xiao Ying Gong
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354, Freising, Germany
| | - Kristine Y Crous
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Kevin Griffin
- Department of Ecology, Evolution and Environmental Biology (E3B), Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA
| | - Danielle Way
- Department of Biology, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Matthew Turnbull
- Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, PB 4800, Christchurch, New Zealand
| | - Mark A Adams
- Centre for Carbon, Water and Food, University of Sydney, 380 Werombi Rd, Brownlow Hill, NSW, 2570, Australia
| | - Owen K Atkin
- ARC Centre of Excellence in Plant Energy Biology, Division of Plant Science, Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Graham D Farquhar
- Research School of Biology, College of Science, and ARC Center of Excellence for Translational Photosynthesis, Australian National University, Canberra, ACT, 2601, Australia
| | - Gabriel Cornic
- Ecologie Systématique Evolution, Université Paris-Sud, 91405, Orsay Cedex, France
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35
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Estimation of Photorespiratory Fluxes by Gas Exchange. Methods Mol Biol 2017. [PMID: 28822122 DOI: 10.1007/978-1-4939-7225-8_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Photorespiratory fluxes can be easily estimated by photosynthetic gas exchange using an infrared gas analyzer and applying the Farquhar, von Caemmerer, and Berry (Farquhar et al. Planta 149:78-90, 1980) photosynthesis model. For a more direct measurement of photorespiratory CO2 release from glycine decarboxylation, infrared gas analysis can be coupled to membrane-inlet mass spectrometry, capable of separating the total CO2 concentration into its 12CO2 and 13CO2 components in a continuous online fashion. This chapter discusses how to calculate rates of photorespiration from Rubisco kinetics and describes in detail a method for measuring the CO2 release from glycine decarboxylation using 13CO2.
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36
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Ma F, Jazmin LJ, Young JD, Allen DK. Isotopically Nonstationary Metabolic Flux Analysis (INST-MFA) of Photosynthesis and Photorespiration in Plants. Methods Mol Biol 2017; 1653:167-194. [PMID: 28822133 DOI: 10.1007/978-1-4939-7225-8_12] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Photorespiration is a central component of photosynthesis; however to better understand its role it should be viewed in the context of an integrated metabolic network rather than a series of individual reactions that operate independently. Isotopically nonstationary 13C metabolic flux analysis (INST-MFA), which is based on transient labeling studies at metabolic steady state, offers a comprehensive platform to quantify plant central metabolism. In this chapter, we describe the application of INST-MFA to investigate metabolism in leaves. Leaves are an autotrophic tissue, assimilating CO2 over a diurnal period implying that the metabolic steady state is limited to less than 12 h and thus requiring an INST-MFA approach. This strategy results in a comprehensive unified description of photorespiration, Calvin cycle, sucrose and starch synthesis, tricarboxylic acid (TCA) cycle, and amino acid biosynthetic fluxes. We present protocols of the experimental aspects for labeling studies: transient 13CO2 labeling of leaf tissue, sample quenching and extraction, mass spectrometry (MS) analysis of isotopic labeling data, measurement of sucrose and amino acids in vascular exudates, and provide details on the computational flux estimation using INST-MFA.
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Affiliation(s)
- Fangfang Ma
- Donald Danforth Plant Science Center, St. Louis, MO, USA
| | - Lara J Jazmin
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Jamey D Young
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Doug K Allen
- Donald Danforth Plant Science Center, St. Louis, MO, USA.
- United States Department of Agriculture, Agricultural Research Service, St. Louis, MO, USA.
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37
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Rogers A, Medlyn BE, Dukes JS, Bonan G, von Caemmerer S, Dietze MC, Kattge J, Leakey ADB, Mercado LM, Niinemets Ü, Prentice IC, Serbin SP, Sitch S, Way DA, Zaehle S. A roadmap for improving the representation of photosynthesis in Earth system models. THE NEW PHYTOLOGIST 2017; 213:22-42. [PMID: 27891647 DOI: 10.1111/nph.14283] [Citation(s) in RCA: 194] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 09/16/2016] [Indexed: 05/18/2023]
Abstract
Accurate representation of photosynthesis in terrestrial biosphere models (TBMs) is essential for robust projections of global change. However, current representations vary markedly between TBMs, contributing uncertainty to projections of global carbon fluxes. Here we compared the representation of photosynthesis in seven TBMs by examining leaf and canopy level responses of photosynthetic CO2 assimilation (A) to key environmental variables: light, temperature, CO2 concentration, vapor pressure deficit and soil water content. We identified research areas where limited process knowledge prevents inclusion of physiological phenomena in current TBMs and research areas where data are urgently needed for model parameterization or evaluation. We provide a roadmap for new science needed to improve the representation of photosynthesis in the next generation of terrestrial biosphere and Earth system models.
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Affiliation(s)
- Alistair Rogers
- Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, 11973-5000, USA
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, University of Western Sydney, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Jeffrey S Dukes
- Department of Forestry and Natural Resources and Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907-2061, USA
| | - Gordon Bonan
- National Center for Atmospheric Research, Boulder, CO, 80307-3000, USA
| | - Susanne von Caemmerer
- Research School of Biology, College of Medicine, Biology and the Environment, The Australian National University, Linnaeus Building (Bldg 134) Linnaeus Way, Canberra, ACT, 0200, Australia
| | - Michael C Dietze
- Department of Earth and Environment, Boston University, Boston, MA, 02215, USA
| | - Jens Kattge
- Max Planck Institute for Biogeochemistry, 07701, Jena, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany
| | - Andrew D B Leakey
- Department of Plant Biology and Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Lina M Mercado
- Geography Department, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4SB, UK
- Center for Ecology and Hydrology, Wallingford, OX10 8BB, UK
| | - Ülo Niinemets
- Department of Plant Physiology, Estonian University of Life Sciences, Kreutzwaldi 1, 51014, Tartu, Estonia
| | - I Colin Prentice
- AXA Chair of Biosphere and Climate Impacts, Grand Challenges in Ecosystems and the Environment and Grantham Institute for Climate Change, Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, SL5 7PY, UK
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Forestry, Northwest Agriculture & Forestry University, Yangling, 712100, China
| | - Shawn P Serbin
- Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, 11973-5000, USA
| | - Stephen Sitch
- Geography Department, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4SB, UK
| | - Danielle A Way
- Department of Biology, University of Western Ontario, London, ON, N6A 5B7, Canada
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | - Sönke Zaehle
- Biogeochemical Integration Department, Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
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38
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de Oliveira Silva FM, de Ávila Silva L, Araújo WL, Zsögön A, Nunes-Nesi A. Exploiting Natural Variation to Discover Candidate Genes Involved in Photosynthesis-Related Traits. Methods Mol Biol 2017; 1653:125-135. [PMID: 28822130 DOI: 10.1007/978-1-4939-7225-8_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Naturally occurring genetic variation in plants can be very useful to dissect the complex regulation of primary metabolism as well as of physiological traits such as photosynthesis and photorespiration. The physiological and genetic mechanisms underlying natural variation in closely related species or accessions may provide important information that can be used to improve crop yield. In this chapter we describe in detail the use of a population of introgression lines (ILs), with the Solanum pennellii IL population as a study case, as a tool for the identification of genomic regions involved in the control of photosynthetic efficiency.
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Affiliation(s)
| | - Lucas de Ávila Silva
- Departmento de Biologia Vegetal, Universidade Federal de Viçosa, Campus UFR, Viçosa, MG, 36570-000, Brazil
| | - Wagner L Araújo
- Departmento de Biologia Vegetal, Universidade Federal de Viçosa, Campus UFR, Viçosa, MG, 36570-000, Brazil
| | - Agustin Zsögön
- Departmento de Biologia Vegetal, Universidade Federal de Viçosa, Campus UFR, Viçosa, MG, 36570-000, Brazil
| | - Adriano Nunes-Nesi
- Departmento de Biologia Vegetal, Universidade Federal de Viçosa, Campus UFR, Viçosa, MG, 36570-000, Brazil.
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39
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Obata T, Florian A, Timm S, Bauwe H, Fernie AR. On the metabolic interactions of (photo)respiration. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3003-14. [PMID: 27029352 DOI: 10.1093/jxb/erw128] [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] [Indexed: 05/04/2023]
Abstract
Given that photorespiration is inextricably linked to the process of photosynthesis by virtue of sharing the common first enzyme Rubisco, the photorespiratory pathway has been less subject to study in isolation than many other metabolic pathways. That said, despite often being described to be linked to reactions of ammonia assimilation, C1 metabolism and respiratory metabolism, the precise molecular mechanisms governing these linkages in land plants remain partially obscure. The application of broad metabolite profiling on mutants with altered levels of metabolic enzymes has facilitated the identification of common and distinct metabolic responses among them. Here we provide an update of the recent findings from such studies, focusing particularly on the interplay between photorespiration and the metabolic reactions of mitochondrial respiration. In order to do so we evaluated (i) changes in organic acids following environmental perturbation of metabolism, (ii) changes in organic acid levels in a wide range of photorespiratory mutants, (iii) changes in levels of photorespiratory metabolites in transgenic tomato lines deficient in the expression of enzymes of the tricarboxylic acid cycle. In addition, we estimated the rates of photorespiration in a complete set of tricarboxylic acid cycle transgenic tomato lines. Finally, we discuss insight concerning the interaction between photorespiration and other pathways that has been attained following the development of (13)CO2-based flux profiling methods.
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Affiliation(s)
- Toshihiro Obata
- Max-Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Alexandra Florian
- Max-Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Stefan Timm
- Plant Physiology Department, University of Rostock, D-18051 Rostock, Germany
| | - Hermann Bauwe
- Plant Physiology Department, University of Rostock, D-18051 Rostock, Germany
| | - Alisdair R Fernie
- Max-Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
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40
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Hanson DT, Stutz SS, Boyer JS. Why small fluxes matter: the case and approaches for improving measurements of photosynthesis and (photo)respiration. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3027-39. [PMID: 27099373 PMCID: PMC4867897 DOI: 10.1093/jxb/erw139] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Since its inception, the Farquhar et al. (1980) model of photosynthesis has been a mainstay for relating biochemistry to environmental conditions from chloroplast to global levels in terrestrial plants. Many variables could be assigned from basic enzyme kinetics, but the model also required measurements of maximum rates of photosynthetic electron transport (J max ), carbon assimilation (Vcmax ), conductance of CO2 into (g s ) and through (g m ) the leaf, and the rate of respiration during the day (R d ). This review focuses on improving the accuracy of these measurements, especially fluxes from photorespiratory CO2, CO2 in the transpiration stream, and through the leaf epidermis and cuticle. These fluxes, though small, affect the accuracy of all methods of estimating mesophyll conductance and several other photosynthetic parameters because they all require knowledge of CO2 concentrations in the intercellular spaces. This review highlights modified methods that may help to reduce some of the uncertainties. The approaches are increasingly important when leaves are stressed or when fluxes are inferred at scales larger than the leaf.
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Affiliation(s)
- David T Hanson
- Department of Biology, MSC03-2020, 1 University of New Mexico, Albuquerque, NM 87131, USA
| | - Samantha S Stutz
- Department of Biology, MSC03-2020, 1 University of New Mexico, Albuquerque, NM 87131, USA
| | - John S Boyer
- Interdisciplinary Plant Group, 1-31 Agriculture Building, University of Missouri, Columbia, MO 65211, USA
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Sejima T, Hanawa H, Shimakawa G, Takagi D, Suzuki Y, Fukayama H, Makino A, Miyake C. Post-illumination transient O 2 -uptake is driven by photorespiration in tobacco leaves. PHYSIOLOGIA PLANTARUM 2016; 156:227-238. [PMID: 26387965 DOI: 10.1111/ppl.12388] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 07/22/2015] [Accepted: 08/03/2015] [Indexed: 06/05/2023]
Abstract
This study aims to elucidate the molecular mechanism for the transient increase in the O2 -uptake rate in tobacco (Nicotiana tabacum cv Xanthi) leaves after turning off actinic lights (ALs). The photosynthetic O2 evolution rate reaches a maximum shortly after the onset of illumination with ALs and then decreases to zero in atmospheric CO2 /O2 conditions. After turning off the ALs, tobacco leaves show a transient increase in the O2 -uptake rate, the post-illumination transient O2 -uptake, and thereafter, the O2 -uptake rate decreases to the level of the dark-respiration rate. Photosynthetic linear electron flow, evaluated as the quantum yield of photosystem II [Y(II)], maintained a steady-state value distinct from the photosynthetic O2 -evolution rate. In high-[CO2 ] conditions, the photosynthetic O2 -evolution rate and Y(II) showed a parallel behavior, and the post-illumination transient O2 -uptake was suppressed. On the other hand, in maize leaves (a C4 plant), even in atmospheric CO2 /O2 conditions, Y(II) paralleled the photosynthetic O2 -evolution rate and the post-illumination transient O2 -uptake was suppressed. Hypothesizing that the post-illumination transient O2 -uptake is driven by C3 plant photorespiration in tobacco leaves, we calculated both the ribulose 1,5-bisphosphate carboxylase- and oxygenase-rates (Vc and Vo) from photosynthetic O2 -evolution and the post-illumination transient O2 -uptake rates. These values corresponded to those estimated from simultaneous chlorophyll fluorescence/O2 -exchange analysis. Furthermore, the H+ -consumption rate for ATP synthesis in both photosynthesis and photorespiration, calculated from both Vc and Vo that were estimated from chlorophyll fluorescence/CO2 -exchange analysis, showed a positive linear relationship with the dissipation rate of the electrochromic shift signal. Thus, these findings support our hypothesis.
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Affiliation(s)
- Takehiro Sejima
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Hitomi Hanawa
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Ginga Shimakawa
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Daisuke Takagi
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Yuji Suzuki
- Department of Applied Plant Science, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Hiroshi Fukayama
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Amane Makino
- Department of Applied Plant Science, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Chikahiro Miyake
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
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Allen DK. Quantifying plant phenotypes with isotopic labeling & metabolic flux analysis. Curr Opin Biotechnol 2015; 37:45-52. [PMID: 26613198 DOI: 10.1016/j.copbio.2015.10.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/04/2015] [Accepted: 10/06/2015] [Indexed: 12/14/2022]
Abstract
Analyses of metabolic flux using stable isotopes in plants have traditionally been restricted to tissues with presumed homogeneous cell populations and long metabolic steady states such as developing seeds, cell suspensions, or cultured roots and root tips. It is now possible to describe these and other metabolically more dynamic tissues such as leaves in greater detail using novel methods in mass spectrometry, isotope labeling strategies, and transient labeling-based flux analyses. Such studies are necessary for a systems level description of plant function that more closely represents biological reality, and provides insights into the genes that will need to be modified as natural resources become ever more limited and environments change.
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Affiliation(s)
- Doug K Allen
- United States Department of Agriculture-Agricultural Research Service, Plant Genetics Research Unit, 975 North Warson Road, St. Louis, MO 63132, United States; Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO 63132, United States.
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Ellsworth DS, Crous KY, Lambers H, Cooke J. Phosphorus recycling in photorespiration maintains high photosynthetic capacity in woody species. PLANT, CELL & ENVIRONMENT 2015; 38:1142-56. [PMID: 25311401 DOI: 10.1111/pce.12468] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Accepted: 09/25/2014] [Indexed: 05/13/2023]
Abstract
Leaf photosynthetic CO2 responses can provide insight into how major nutrients, such as phosphorus (P), constrain leaf CO2 assimilation rates (Anet). However, triose-phosphate limitations are rarely employed in the classic photosynthesis model and it is uncertain as to what extent these limitations occur in field situations. In contrast to predictions from biochemical theory of photosynthesis, we found consistent evidence in the field of lower Anet in high [CO2] and low [O2 ] than at ambient [O2 ]. For 10 species of trees and shrubs across a range of soil P availability in Australia, none of them showed a positive response of Anet at saturating [CO2] (i.e. Amax) to 2 kPa O2. Three species showed >20% reductions in Amax in low [O2], a phenomenon potentially explained by orthophosphate (Pi) savings during photorespiration. These species, with largest photosynthetic capacity and Pi > 2 mmol P m(-2), rely the most on additional Pi made available from photorespiration rather than species growing in P-impoverished soils. The results suggest that rarely used adjustments to a biochemical photosynthesis model are useful for predicting Amax and give insight into the biochemical limitations of photosynthesis rates at a range of leaf P concentrations. Phosphate limitations to photosynthetic capacity are likely more common in the field than previously considered.
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Affiliation(s)
- David S Ellsworth
- Hawkesbury Institute for the Environment, University of Western Sydney, Penrith, New South Wales, 2751, Australia
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Dalal J, Lopez H, Vasani NB, Hu Z, Swift JE, Yalamanchili R, Dvora M, Lin X, Xie D, Qu R, Sederoff HW. A photorespiratory bypass increases plant growth and seed yield in biofuel crop Camelina sativa. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:175. [PMID: 26516348 DOI: 10.1186/s13068-015-0357-351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 10/14/2015] [Indexed: 05/22/2023]
Abstract
BACKGROUND Camelina sativa is an oilseed crop with great potential for biofuel production on marginal land. The seed oil from camelina has been converted to jet fuel and improved fuel efficiency in commercial and military test flights. Hydrogenation-derived renewable diesel from camelina is environmentally superior to that from canola due to lower agricultural inputs, and the seed meal is FDA approved for animal consumption. However, relatively low yield makes its farming less profitable. Our study is aimed at increasing camelina seed yield by reducing carbon loss from photorespiration via a photorespiratory bypass. Genes encoding three enzymes of the Escherichia coli glycolate catabolic pathway were introduced: glycolate dehydrogenase (GDH), glyoxylate carboxyligase (GCL) and tartronic semialdehyde reductase (TSR). These enzymes compete for the photorespiratory substrate, glycolate, convert it to glycerate within the chloroplasts, and reduce photorespiration. As a by-product of the reaction, CO2 is released in the chloroplast, which increases photosynthesis. Camelina plants were transformed with either partial bypass (GDH), or full bypass (GDH, GCL and TSR) genes. Transgenic plants were evaluated for physiological and metabolic traits. RESULTS Expressing the photorespiratory bypass genes in camelina reduced photorespiration and increased photosynthesis in both partial and full bypass expressing lines. Expression of partial bypass increased seed yield by 50-57 %, while expression of full bypass increased seed yield by 57-73 %, with no loss in seed quality. The transgenic plants also showed increased vegetative biomass and faster development; they flowered, set seed and reached seed maturity about 1 week earlier than WT. At the transcriptional level, transgenic plants showed differential expression in categories such as respiration, amino acid biosynthesis and fatty acid metabolism. The increased growth of the bypass transgenics compared to WT was only observed in ambient or low CO2 conditions, but not in elevated CO2 conditions. CONCLUSIONS The photorespiratory bypass is an effective approach to increase photosynthetic productivity in camelina. By reducing photorespiratory losses and increasing photosynthetic CO2 fixation rates, transgenic plants show dramatic increases in seed yield. Because photorespiration causes losses in productivity of most C3 plants, the bypass approach may have significant impact on increasing agricultural productivity for C3 crops.
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Affiliation(s)
- Jyoti Dalal
- Department of Crop Science, North Carolina State University, Campus Box 7287, Raleigh, NC 27695-7287 USA
| | - Harry Lopez
- Department of Crop Science, North Carolina State University, Campus Box 7287, Raleigh, NC 27695-7287 USA
| | - Naresh B Vasani
- Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695-7612 USA
| | - Zhaohui Hu
- Department of Crop Science, North Carolina State University, Campus Box 7287, Raleigh, NC 27695-7287 USA
| | - Jennifer E Swift
- Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695-7612 USA
| | - Roopa Yalamanchili
- Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695-7612 USA
| | - Mia Dvora
- Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695-7612 USA
| | - Xiuli Lin
- Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695-7612 USA
| | - Deyu Xie
- Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695-7612 USA
| | - Rongda Qu
- Department of Crop Science, North Carolina State University, Campus Box 7287, Raleigh, NC 27695-7287 USA
| | - Heike W Sederoff
- Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695-7612 USA
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Dalal J, Lopez H, Vasani NB, Hu Z, Swift JE, Yalamanchili R, Dvora M, Lin X, Xie D, Qu R, Sederoff HW. A photorespiratory bypass increases plant growth and seed yield in biofuel crop Camelina sativa. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:175. [PMID: 26516348 PMCID: PMC4625952 DOI: 10.1186/s13068-015-0357-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 10/14/2015] [Indexed: 05/03/2023]
Abstract
BACKGROUND Camelina sativa is an oilseed crop with great potential for biofuel production on marginal land. The seed oil from camelina has been converted to jet fuel and improved fuel efficiency in commercial and military test flights. Hydrogenation-derived renewable diesel from camelina is environmentally superior to that from canola due to lower agricultural inputs, and the seed meal is FDA approved for animal consumption. However, relatively low yield makes its farming less profitable. Our study is aimed at increasing camelina seed yield by reducing carbon loss from photorespiration via a photorespiratory bypass. Genes encoding three enzymes of the Escherichia coli glycolate catabolic pathway were introduced: glycolate dehydrogenase (GDH), glyoxylate carboxyligase (GCL) and tartronic semialdehyde reductase (TSR). These enzymes compete for the photorespiratory substrate, glycolate, convert it to glycerate within the chloroplasts, and reduce photorespiration. As a by-product of the reaction, CO2 is released in the chloroplast, which increases photosynthesis. Camelina plants were transformed with either partial bypass (GDH), or full bypass (GDH, GCL and TSR) genes. Transgenic plants were evaluated for physiological and metabolic traits. RESULTS Expressing the photorespiratory bypass genes in camelina reduced photorespiration and increased photosynthesis in both partial and full bypass expressing lines. Expression of partial bypass increased seed yield by 50-57 %, while expression of full bypass increased seed yield by 57-73 %, with no loss in seed quality. The transgenic plants also showed increased vegetative biomass and faster development; they flowered, set seed and reached seed maturity about 1 week earlier than WT. At the transcriptional level, transgenic plants showed differential expression in categories such as respiration, amino acid biosynthesis and fatty acid metabolism. The increased growth of the bypass transgenics compared to WT was only observed in ambient or low CO2 conditions, but not in elevated CO2 conditions. CONCLUSIONS The photorespiratory bypass is an effective approach to increase photosynthetic productivity in camelina. By reducing photorespiratory losses and increasing photosynthetic CO2 fixation rates, transgenic plants show dramatic increases in seed yield. Because photorespiration causes losses in productivity of most C3 plants, the bypass approach may have significant impact on increasing agricultural productivity for C3 crops.
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Affiliation(s)
- Jyoti Dalal
- />Department of Crop Science, North Carolina State University, Campus Box 7287, Raleigh, NC 27695-7287 USA
| | - Harry Lopez
- />Department of Crop Science, North Carolina State University, Campus Box 7287, Raleigh, NC 27695-7287 USA
| | - Naresh B. Vasani
- />Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695-7612 USA
| | - Zhaohui Hu
- />Department of Crop Science, North Carolina State University, Campus Box 7287, Raleigh, NC 27695-7287 USA
| | - Jennifer E. Swift
- />Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695-7612 USA
| | - Roopa Yalamanchili
- />Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695-7612 USA
| | - Mia Dvora
- />Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695-7612 USA
| | - Xiuli Lin
- />Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695-7612 USA
| | - Deyu Xie
- />Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695-7612 USA
| | - Rongda Qu
- />Department of Crop Science, North Carolina State University, Campus Box 7287, Raleigh, NC 27695-7287 USA
| | - Heike W. Sederoff
- />Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC 27695-7612 USA
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Heise R, Fernie AR, Stitt M, Nikoloski Z. Pool size measurements facilitate the determination of fluxes at branching points in non-stationary metabolic flux analysis: the case of Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2015; 6:386. [PMID: 26082786 PMCID: PMC4451360 DOI: 10.3389/fpls.2015.00386] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 05/14/2015] [Indexed: 05/08/2023]
Abstract
Pool size measurements are important for the estimation of absolute intracellular fluxes in particular scenarios based on data from heavy carbon isotope experiments. Recently, steady-state fluxes estimates were obtained for central carbon metabolism in an intact illuminated rosette of Arabidopsis thaliana grown photoautotrophically (Szecowka et al., 2013; Heise et al., 2014). Fluxes were estimated therein by integrating mass-spectrometric data of the dynamics of the unlabeled metabolic fraction, data on metabolic pool sizes, partitioning of metabolic pools between cellular compartments and estimates of photosynthetically inactive pools, with a simplified model of plant central carbon metabolism. However, the fluxes were determined by treating the pool sizes as fixed parameters. Here we investigated whether and, if so, to what extent the treatment of pool sizes as parameters to be optimized in three scenarios may affect the flux estimates. The results are discussed in terms of benchmark values for canonical pathways and reactions, including starch and sucrose synthesis as well as the ribulose-1,5-bisphosphate carboxylation and oxygenation reactions. In addition, we discuss pathways emerging from a divergent branch point for which pool sizes are required for flux estimation, irrespective of the computational approach used for the simulation of the observable labeling pattern. Therefore, our findings indicate the necessity for development of techniques for accurate pool size measurements to improve the quality of flux estimates from non-stationary flux estimates in intact plant cells in the absence of alternative flux measurements.
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Affiliation(s)
- Robert Heise
- Systems Biology and Mathematical Modeling Group, Max Planck Institute of Molecular Plant PhysiologyPotsdam, Germany
| | - Alisdair R. Fernie
- Central Metabolism Group, Max Planck Institute of Molecular Plant PhysiologyPotsdam, Germany
| | - Mark Stitt
- System Regulation Group, Max Planck Institute of Molecular Plant PhysiologyPotsdam, Germany
| | - Zoran Nikoloski
- Systems Biology and Mathematical Modeling Group, Max Planck Institute of Molecular Plant PhysiologyPotsdam, Germany
- *Correspondence: Zoran Nikoloski, Systems Biology and Mathematical Modeling Group, Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany
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Isotopically nonstationary 13C flux analysis of changes in Arabidopsis thaliana leaf metabolism due to high light acclimation. Proc Natl Acad Sci U S A 2014; 111:16967-72. [PMID: 25368168 DOI: 10.1073/pnas.1319485111] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Improving plant productivity is an important aim for metabolic engineering. There are few comprehensive methods that quantitatively describe leaf metabolism, although such information would be valuable for increasing photosynthetic capacity, enhancing biomass production, and rerouting carbon flux toward desirable end products. Isotopically nonstationary metabolic flux analysis (INST-MFA) has been previously applied to map carbon fluxes in photoautotrophic bacteria, which involves model-based regression of transient (13)C-labeling patterns of intracellular metabolites. However, experimental and computational difficulties have hindered its application to terrestrial plant systems. We performed in vivo isotopic labeling of Arabidopsis thaliana rosettes with (13)CO2 and estimated fluxes throughout leaf photosynthetic metabolism by INST-MFA. Plants grown at 200 µmol m(-2)s(-1) light were compared with plants acclimated for 9 d at an irradiance of 500 µmol⋅m(-2)⋅s(-1). Approximately 1,400 independent mass isotopomer measurements obtained from analysis of 37 metabolite fragment ions were regressed to estimate 136 total fluxes (54 free fluxes) under each condition. The results provide a comprehensive description of changes in carbon partitioning and overall photosynthetic flux after long-term developmental acclimation of leaves to high light. Despite a doubling in the carboxylation rate, the photorespiratory flux increased from 17 to 28% of net CO2 assimilation with high-light acclimation (Vc/Vo: 3.5:1 vs. 2.3:1, respectively). This study highlights the potential of (13)C INST-MFA to describe emergent flux phenotypes that respond to environmental conditions or plant physiology and cannot be obtained by other complementary approaches.
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48
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Carvalho FEL, Ribeiro CW, Martins MO, Bonifacio A, Staats CC, Andrade CMB, Cerqueira JV, Margis-Pinheiro M, Silveira JAG. Cytosolic APX knockdown rice plants sustain photosynthesis by regulation of protein expression related to photochemistry, Calvin cycle and photorespiration. PHYSIOLOGIA PLANTARUM 2014; 150:632-645. [PMID: 24329817 DOI: 10.1111/ppl.12143] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Revised: 11/27/2013] [Accepted: 12/27/2013] [Indexed: 06/03/2023]
Abstract
The biochemical mechanisms underlying the involvement of cytosolic ascorbate peroxidases (cAPXs) in photosynthesis are still unknown. In this study, rice plants doubly silenced in these genes (APX1/2) were exposed to moderate light (ML) and high light (HL) to assess the role of cAPXs in photosynthetic efficiency. APX1/2 mutants that were exposed to ML overexpressed seven and five proteins involved in photochemical activity and photorespiration, respectively. These plants also increased the pheophytin and chlorophyll levels, but the amount of five proteins that are important for Calvin cycle did not change. These responses in mutants were associated with Rubisco carboxylation rate, photosystem II (PSII) activity and potential photosynthesis, which were similar to non-transformed plants. The upregulation of photochemical proteins may be part of a compensatory mechanism for APX1/2 deficiency but apparently the finer-control for photosynthesis efficiency is dependent on Calvin cycle proteins. Conversely, under HL the mutants employed a different strategy, triggering downregulation of proteins related to photochemical activity, Calvin cycle and decreasing the levels of photosynthetic pigments. These changes were associated to strong impairment in PSII activity and Rubisco carboxylation. The upregulation of some photorespiratory proteins was maintained under that stressful condition and this response may have contributed to photoprotection in rice plants deficient in cAPXs. The data reveal that the two cAPXs are not essential for photosynthesis in rice or, alternatively, the deficient plants are able to trigger compensatory mechanisms to photosynthetic acclimation under ML and HL conditions. These mechanisms involve differential regulation in protein expression related to photochemistry, Calvin cycle and photorespiration.
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Affiliation(s)
- Fabrício E L Carvalho
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, CE, Brazil
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49
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Sage RF. Photorespiratory compensation: a driver for biological diversity. PLANT BIOLOGY (STUTTGART, GERMANY) 2013; 15:624-638. [PMID: 23656429 DOI: 10.1111/plb.12024] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 02/07/2013] [Indexed: 06/02/2023]
Abstract
This paper reviews how terrestrial plants reduce photorespiration and thus compensate for its inhibitory effects. As shown in the equation φ = (1/Sc/o )O/C, where φ is the ratio of oxygenation to carboxylation, Sc/o is the relative specificity of Rubisco, O is stromal O2 level and C is the stromal CO2 concentration, plants can reduce photorespiration by increasing Sc/o or C, or by reducing O. By far the most effective means of reducing φ is by concentrating CO2, as occurs in C4 and CAM plants, and to a lesser extent in plants using a glycine shuttle to concentrate CO2 into the bundle sheath. Trapping and refixation of photorespired CO2 by a sheath of chloroplasts around the mesophyll cell periphery in C3 plants also enhances C, particularly at low atmospheric CO2. O2 removal is not practical because high energy and protein investment is needed to have more than a negligible effect. Sc/o enhancement provides for modest reductions in φ, but at the potential cost of limiting the kcat of Rubisco. An effective means of decreasing φ and enhancing carbon gain is to lower leaf temperature by reducing absorbance of solar radiation, or where water is abundant, opening stomata. By using a combination of mechanisms, C3 plants can achieve substantial (>30%) reductions in φ. This may have allowed many C3 species to withstand severe competition from C4 plants in low CO2 atmospheres of recent geological time, thereby preserving some of the Earth's floristic diversity that accumulated over millions of years.
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Affiliation(s)
- R F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada.
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50
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Weber APM, Bauwe H. Photorespiration--a driver for evolutionary innovations and key to better crops. PLANT BIOLOGY (STUTTGART, GERMANY) 2013; 15:621-3. [PMID: 23786418 DOI: 10.1111/plb.12036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
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