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Ubierna N, Holloway-Phillips MM, Wingate L, Ogée J, Busch FA, Farquhar GD. Using Carbon Stable Isotopes to Study C 3 and C 4 Photosynthesis: Models and Calculations. Methods Mol Biol 2024; 2790:163-211. [PMID: 38649572 DOI: 10.1007/978-1-0716-3790-6_10] [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: 04/25/2024]
Abstract
Stable carbon isotopes are a powerful tool to study photosynthesis. Initial applications consisted of determining isotope ratios of plant biomass using mass spectrometry. Subsequently, theoretical models relating C isotope values to gas exchange characteristics were introduced and tested against instantaneous online measurements of 13C photosynthetic discrimination. Beginning in the twenty-first century, laser absorption spectroscopes with sufficient precision for determining isotope mixing ratios became commercially available. This has allowed collection of large data sets at lower cost and with unprecedented temporal resolution. More data and accompanying knowledge have permitted refinement of 13C discrimination model equations, but often at the expense of increased model complexity and difficult parametrization. This chapter describes instantaneous online measurements of 13C photosynthetic discrimination, provides recommendations for experimental setup, and presents a thorough compilation of equations available to researchers. We update our previous 2018 version of this chapter by including recently improved descriptions of (photo)respiratory processes and associated fractionations. We discuss the capabilities and limitations of the diverse 13C discrimination model equations and provide guidance for selecting the model complexity needed for different applications.
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Affiliation(s)
- Nerea Ubierna
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Meisha-Marika Holloway-Phillips
- Research Unit of Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmendsorf, Switzerland
| | - Lisa Wingate
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Jérôme Ogée
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Florian A Busch
- School of Biosciences and The Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Canberra, ACT, Australia
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Salomón RL, Rodríguez-Calcerrada J, De Roo L, Miranda JC, Bodé S, Boeckx P, Steppe K. Carbon isotope composition of respired CO2 in woody stems and leafy shoots of three tree species along the growing season: physiological drivers for respiratory fractionation. TREE PHYSIOLOGY 2023; 43:1731-1744. [PMID: 37471648 DOI: 10.1093/treephys/tpad091] [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: 05/30/2023] [Revised: 07/10/2023] [Accepted: 07/17/2023] [Indexed: 07/22/2023]
Abstract
The carbon isotope composition of respired CO2 (δ13CR) and bulk organic matter (δ13CB) of various plant compartments informs about the isotopic fractionation and substrate of respiratory processes, which are crucial to advance the understanding of carbon allocation in plants. Nevertheless, the variation across organs, species and seasons remains poorly understood. Cavity Ring-Down Laser Spectroscopy was applied to measure δ13CR in leafy shoots and woody stems of maple (Acer platanoides L.), oak (Quercus robur L.) and cedar (Thuja occidentalis L.) trees during spring and late summer. Photosynthesis, respiration, growth and non-structural carbohydrates were measured in parallel to evaluate potential drivers for respiratory fractionation. The CO2 respired by maple and oak shoots was 13C-enriched relative to δ13CB during spring, but not late summer or in the stem. In cedar, δ13CR did not vary significantly throughout organs and seasons, with respired CO2 being 13C-depleted relative to δ13CB. Shoot δ13CR was positively related to leaf starch concentration in maple, while stem δ13CR was inversely related to stem growth. These relations were not significant for oak or cedar. The variability in δ13CR suggests (i) different contributions of respiratory pathways between organs and (ii) seasonality in the respiratory substrate and constitutive compounds for wood formation in deciduous species, less apparent in evergreen cedar, whose respiratory metabolism might be less variable.
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Affiliation(s)
- Roberto L Salomón
- Department of Plants and Crops, Faculty of Bioscience Engineering, Laboratory of Plant Ecology, Ghent University, Coupure links 653, Ghent 9000, Belgium
- Departamento de Sistemas y Recursos Naturales, Research Group FORESCENT, Universidad Politécnica de Madrid, Jose Antonio Novais 10, 28040, Madrid, Spain
| | - Jesús Rodríguez-Calcerrada
- Departamento de Sistemas y Recursos Naturales, Research Group FORESCENT, Universidad Politécnica de Madrid, Jose Antonio Novais 10, 28040, Madrid, Spain
| | - Linus De Roo
- Department of Plants and Crops, Faculty of Bioscience Engineering, Laboratory of Plant Ecology, Ghent University, Coupure links 653, Ghent 9000, Belgium
| | - José Carlos Miranda
- Departamento de Sistemas y Recursos Naturales, Research Group FORESCENT, Universidad Politécnica de Madrid, Jose Antonio Novais 10, 28040, Madrid, Spain
| | - Samuel Bodé
- Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Isotope Bioscience Laboratory - ISOFYS, Ghent University, Coupure links 653, Gent 9000, Belgium
| | - Pascal Boeckx
- Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Isotope Bioscience Laboratory - ISOFYS, Ghent University, Coupure links 653, Gent 9000, Belgium
| | - Kathy Steppe
- Department of Plants and Crops, Faculty of Bioscience Engineering, Laboratory of Plant Ecology, Ghent University, Coupure links 653, Ghent 9000, Belgium
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Le XH, Millar AH. The diversity of substrates for plant respiration and how to optimize their use. PLANT PHYSIOLOGY 2023; 191:2133-2149. [PMID: 36573332 PMCID: PMC10069909 DOI: 10.1093/plphys/kiac599] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 12/09/2022] [Indexed: 06/18/2023]
Abstract
Plant respiration is a foundational biological process with the potential to be optimized to improve crop yield. To understand and manipulate the outputs of respiration, the inputs of respiration-respiratory substrates-need to be probed in detail. Mitochondria house substrate catabolic pathways and respiratory machinery, so transport into and out of these organelles plays an important role in committing substrates to respiration. The large number of mitochondrial carriers and catabolic pathways that remain unidentified hinder this process and lead to confusion about the identity of direct and indirect respiratory substrates in plants. The sources and usage of respiratory substrates vary and are increasing found to be highly regulated based on cellular processes and environmental factors. This review covers the use of direct respiratory substrates following transport through mitochondrial carriers and catabolism under normal and stressed conditions. We suggest the introduction of enzymes not currently found in plant mitochondria to enable serine and acetate to be direct respiratory substrates in plants. We also compare respiratory substrates by assessing energetic yields, availability in cells, and their full or partial oxidation during cell catabolism. This information can assist in decisions to use synthetic biology approaches to alter the range of respiratory substrates in plants. As a result, respiration could be optimized by introducing, improving, or controlling specific mitochondrial transporters and mitochondrial catabolic pathways.
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Affiliation(s)
- Xuyen H Le
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia
- The ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia
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Tsuji C, Dannoura M, Desalme D, Angeli N, Takanashi S, Kominami Y, Epron D. Drought affects the fate of non-structural carbohydrates in hinoki cypress. TREE PHYSIOLOGY 2022; 42:784-796. [PMID: 34635913 DOI: 10.1093/treephys/tpab135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
Tree species that close stomata early in response to drought are likely to suffer from an imbalance between limited carbohydrate supply due to reduced photosynthesis and metabolic demand. Our objective was to clarify the dynamic responses of non-structural carbohydrates to drought in a water-saving species, the hinoki cypress (Chamaecyparis obtusa Sieb. et Zucc.). To this end, we pulse-labeled young trees with 13CO2 10 days after the beginning of the drought treatment. Trees were harvested 7 days later, early during drought progression, and 86 days later when they had suffered from a long and severe drought. The labeled carbon (C) was traced in phloem extract, in the organic matter and starch of all the organs, and in the soluble sugars (sucrose, glucose and fructose) of the most metabolically active organs (foliage, green branches and fine roots). No drought-related changes in labeled C partitioning between belowground and aboveground organs were observed. The C allocation between non-structural carbohydrates was altered early during drought progression: starch concentration was lower by half in the photosynthetic organs, while the concentration of almost all soluble sugars tended to increase. The preferential allocation of labeled C to glucose and fructose reflected an increased demand for soluble sugars for osmotic adjustment. After 3 months of a lethal drought, the concentrations of soluble sugars and starch were admittedly lower in drought-stressed trees than in the controls, but the pool of non-structural carbohydrates was far from completely depleted. However, the allocation to storage had been impaired by drought; photosynthesis and the sugar translocation rate had also been reduced by drought. Failure to maintain cell turgor through osmoregulation and to refill embolized xylem due to the depletion in soluble sugars in the roots could have resulted in tree mortality in hinoki cypress, though the total pool of carbohydrate was not completely depleted.
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Affiliation(s)
- Chiaki Tsuji
- Graduate School of Environmental Studies, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| | - Masako Dannoura
- Graduate School of Environmental Studies, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Dorine Desalme
- Université de Lorraine, AgroParisTech, INRAE, UMR Silva, 34 cours Léopold, Nancy F-54000, France
| | - Nicolas Angeli
- Université de Lorraine, AgroParisTech, INRAE, UMR Silva, 34 cours Léopold, Nancy F-54000, France
| | - Satoru Takanashi
- Forestry and Forest Products Research Institute, Kansai Research Centre, 68 Nagaikyutaroh, Momoyama, Fushimi, Kyoto 612-0855, Japan
| | - Yuji Kominami
- Forestry and Forest Products Research Institute, 1 Matsunosato, Ibaraki, Tsukuba 305-8687, Japan
| | - Daniel Epron
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
- Université de Lorraine, AgroParisTech, INRAE, UMR Silva, 34 cours Léopold, Nancy F-54000, France
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Le XH, Lee CP, Millar AH. The mitochondrial pyruvate carrier (MPC) complex mediates one of three pyruvate-supplying pathways that sustain Arabidopsis respiratory metabolism. THE PLANT CELL 2021; 33:2776-2793. [PMID: 34137858 PMCID: PMC8408480 DOI: 10.1093/plcell/koab148] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 05/19/2021] [Indexed: 05/03/2023]
Abstract
Malate oxidation by plant mitochondria enables the generation of both oxaloacetate and pyruvate for tricarboxylic acid (TCA) cycle function, potentially eliminating the need for pyruvate transport into mitochondria in plants. Here, we show that the absence of the mitochondrial pyruvate carrier 1 (MPC1) causes the co-commitment loss of its putative orthologs, MPC3/MPC4, and eliminates pyruvate transport into Arabidopsis thaliana mitochondria, proving it is essential for MPC complex function. While the loss of either MPC or mitochondrial pyruvate-generating NAD-malic enzyme (NAD-ME) did not cause vegetative phenotypes, the lack of both reduced plant growth and caused an increase in cellular pyruvate levels, indicating a block in respiratory metabolism, and elevated the levels of branched-chain amino acids at night, a sign of alterative substrate provision for respiration. 13C-pyruvate feeding of leaves lacking MPC showed metabolic homeostasis was largely maintained except for alanine and glutamate, indicating that transamination contributes to the restoration of the metabolic network to an operating equilibrium by delivering pyruvate independently of MPC into the matrix. Inhibition of alanine aminotransferases when MPC1 is absent resulted in extremely retarded phenotypes in Arabidopsis, suggesting all pyruvate-supplying enzymes work synergistically to support the TCA cycle for sustained plant growth.
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Affiliation(s)
- Xuyen H. Le
- School of Molecular Sciences, The University of Western Australia, Crawley, Perth 6009, Australia
- The ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Perth 6009, Australia
| | - Chun-Pong Lee
- School of Molecular Sciences, The University of Western Australia, Crawley, Perth 6009, Australia
- The ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Perth 6009, Australia
| | - A. Harvey Millar
- School of Molecular Sciences, The University of Western Australia, Crawley, Perth 6009, Australia
- The ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Perth 6009, Australia
- Author for correspondence:
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Lim SL, Voon CP, Guan X, Yang Y, Gardeström P, Lim BL. In planta study of photosynthesis and photorespiration using NADPH and NADH/NAD + fluorescent protein sensors. Nat Commun 2020; 11:3238. [PMID: 32591540 PMCID: PMC7320160 DOI: 10.1038/s41467-020-17056-0] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 06/09/2020] [Indexed: 12/21/2022] Open
Abstract
The challenge of monitoring in planta dynamic changes of NADP(H) and NAD(H) redox states at the subcellular level is considered a major obstacle in plant bioenergetics studies. Here, we introduced two circularly permuted yellow fluorescent protein sensors, iNAP and SoNar, into Arabidopsis thaliana to monitor the dynamic changes in NADPH and the NADH/NAD+ ratio. In the light, photosynthesis and photorespiration are linked to the redox states of NAD(P)H and NAD(P) pools in several subcellular compartments connected by the malate-OAA shuttles. We show that the photosynthetic increases in stromal NADPH and NADH/NAD+ ratio, but not ATP, disappear when glycine decarboxylation is inhibited. These observations highlight the complex interplay between chloroplasts and mitochondria during photosynthesis and support the suggestions that, under normal conditions, photorespiration supplies a large amount of NADH to mitochondria, exceeding its NADH-dissipating capacity, and the surplus NADH is exported from the mitochondria to the cytosol through the malate-OAA shuttle.
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Affiliation(s)
- Shey-Li Lim
- School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Chia Pao Voon
- School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Xiaoqian Guan
- School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Yi Yang
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai, China
| | - Per Gardeström
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE-901 87, Umeå, Sweden
| | - Boon Leong Lim
- School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China.
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China.
- HKU Shenzhen Institute of Research and Innovation, Shenzhen, China.
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Werner C, Fasbender L, Romek KM, Yáñez-Serrano AM, Kreuzwieser J. Heat Waves Change Plant Carbon Allocation Among Primary and Secondary Metabolism Altering CO 2 Assimilation, Respiration, and VOC Emissions. FRONTIERS IN PLANT SCIENCE 2020; 11:1242. [PMID: 32922421 PMCID: PMC7456945 DOI: 10.3389/fpls.2020.01242] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 07/29/2020] [Indexed: 05/17/2023]
Abstract
Processes controlling plant carbon allocation among primary and secondary metabolism, i.e., carbon assimilation, respiration, and VOC synthesis are still poorly constrained, particularly regarding their response to stress. To investigate these processes, we simulated a 10-day 38°C heat wave, analysing real-time carbon allocation into primary and secondary metabolism in the Mediterranean shrub Halimium halimifolium L. We traced position-specific 13C-labeled pyruvate into daytime VOC and CO2 emissions and during light-dark transition. Net CO2 assimilation strongly declined under heat, due to three-fold higher respiration rates. Interestingly, day respiration also increased two-fold. Decarboxylation of the C1-atom of pyruvate was the main process driving daytime CO2 release, whereas the C2-moiety was not decarboxylated in the TCA cycle. Heat induced high emissions of methanol, methyl acetate, acetaldehyde as well as mono- and sesquiterpenes, particularly during the first two days. After 10-days of heat a substantial proportion of 13C-labeled pyruvate was allocated into de novo synthesis of VOCs. Thus, during extreme heat waves high respiratory losses and reduced assimilation can shift plants into a negative carbon balance. Still, plants enhanced their investment into de novo VOC synthesis despite associated metabolic CO2 losses. We conclude that heat stress re-directed the proportional flux of key metabolites into pathways of VOC biosynthesis most likely at the expense of reactions of plant primary metabolism, which might highlight their importance for stress protection.
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Affiliation(s)
- Christiane Werner
- Ecosystem Physiology, University of Freiburg, Freiburg, Germany
- *Correspondence: Christiane Werner,
| | - Lukas Fasbender
- Ecosystem Physiology, University of Freiburg, Freiburg, Germany
| | | | - Ana Maria Yáñez-Serrano
- Ecosystem Physiology, University of Freiburg, Freiburg, Germany
- Center of Ecological Research and Forest Applications (CREAF), Universitat Autònoma de Barcelona, Barcelona, Spain
- Global Ecology Unit CREAF-CSIC-UAB, Cerdanyola del Vallès, Barcelona, Spain
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Giuliani R, Karki S, Covshoff S, Lin HC, Coe RA, Koteyeva NK, Evans MA, Quick WP, von Caemmerer S, Furbank RT, Hibberd JM, Edwards GE, Cousins AB. Transgenic maize phosphoenolpyruvate carboxylase alters leaf-atmosphere CO 2 and 13CO 2 exchanges in Oryza sativa. PHOTOSYNTHESIS RESEARCH 2019; 142:153-167. [PMID: 31325077 PMCID: PMC6848035 DOI: 10.1007/s11120-019-00655-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 06/11/2019] [Indexed: 05/07/2023]
Abstract
The engineering process of C4 photosynthesis into C3 plants requires an increased activity of phosphoenolpyruvate carboxylase (PEPC) in the cytosol of leaf mesophyll cells. The literature varies on the physiological effect of transgenic maize (Zea mays) PEPC (ZmPEPC) leaf expression in Oryza sativa (rice). Therefore, to address this issue, leaf-atmosphere CO2 and 13CO2 exchanges were measured, both in the light (at atmospheric O2 partial pressure of 1.84 kPa and at different CO2 levels) and in the dark, in transgenic rice expressing ZmPEPC and wild-type (WT) plants. The in vitro PEPC activity was 25 times higher in the PEPC overexpressing (PEPC-OE) plants (~20% of maize) compared to the negligible activity in WT. In the PEPC-OE plants, the estimated fraction of carboxylation by PEPC (β) was ~6% and leaf net biochemical discrimination against 13CO2[Formula: see text] was ~ 2‰ lower than in WT. However, there were no differences in leaf net CO2 assimilation rates (A) between genotypes, while the leaf dark respiration rates (Rd) over three hours after light-dark transition were enhanced (~ 30%) and with a higher 13C composition [Formula: see text] in the PEPC-OE plants compared to WT. These data indicate that ZmPEPC in the PEPC-OE rice plants contributes to leaf carbon metabolism in both the light and in the dark. However, there are some factors, potentially posttranslational regulation and PEP availability, which reduce ZmPEPC activity in vivo.
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Affiliation(s)
- Rita Giuliani
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, 99164-4236, USA
| | - Shanta Karki
- C4 Rice Center, International Rice Research Institute (IRRI), Los Baños, Philippines
| | - Sarah Covshoff
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK
| | - Hsiang-Chun Lin
- C4 Rice Center, International Rice Research Institute (IRRI), Los Baños, Philippines
| | - Robert A Coe
- C4 Rice Center, International Rice Research Institute (IRRI), Los Baños, Philippines
| | - Nuria K Koteyeva
- Laboratory of Anatomy and Morphology, V.L. Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov Street 2, St. Petersburg, Russia, 197376
| | - Marc A Evans
- Department of Mathematics and Statistics, Washington State University, Pullman, WA, 99164-3113, USA
| | - W Paul Quick
- C4 Rice Center, International Rice Research Institute (IRRI), Los Baños, Philippines
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Susanne von Caemmerer
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia
| | - Robert T Furbank
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia
| | - Julian M Hibberd
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK
| | - Gerald E Edwards
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, 99164-4236, USA
| | - Asaph B Cousins
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, 99164-4236, USA.
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Bögelein R, Lehmann MM, Thomas FM. Differences in carbon isotope leaf-to-phloem fractionation and mixing patterns along a vertical gradient in mature European beech and Douglas fir. THE NEW PHYTOLOGIST 2019; 222:1803-1815. [PMID: 30740705 DOI: 10.1111/nph.15735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 02/03/2019] [Indexed: 05/13/2023]
Abstract
While photosynthetic isotope discrimination is well understood, the postphotosynthetic and transport-related fractionation mechanisms that influence phloem and subsequently tree ring δ13 C are less investigated and may vary among species. We studied the seasonal and diel courses of leaf-to-phloem δ13 C differences of water-soluble organic matter (WSOM) in vertical crown gradients and followed the assimilate transport via the branches to the trunk phloem at breast height in European beech (Fagus sylvatica) and Douglas fir (Pseudotsuga menziesii). δ13 C of individual sugars and cyclitols from a subsample was determined by compound-specific isotope analysis. In beech, leaf-to-phloem δ13 C differences in WSOM increased with height and were partly caused by biochemical isotope fractionation between leaf compounds. 13 C-Enrichment of phloem sugars relative to leaf sucrose implies an additional isotope fractionation mechanism related to leaf assimilate export. In Douglas fir, leaf-to-phloem δ13 C differences were much smaller and isotopically invariant pinitol strongly influenced leaf and phloem WSOM. Trunk phloem WSOM at breast height reflected canopy-integrated δ13 C in beech but not in Douglas fir. Our results demonstrate that leaf-to-phloem isotope fractionation and δ13 C mixing patterns along vertical gradients can differ between tree species. These effects have to be considered for functional interpretations of trunk phloem and tree ring δ13 C.
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Affiliation(s)
- Rebekka Bögelein
- Faculty of Regional and Environmental Sciences - Geobotany, University of Trier, Behringstraße 21, Trier, 54296, Germany
| | - Marco M Lehmann
- Forest Dynamics, Swiss Federal Institute WSL Birmensdorf, Zuercherstrasse 111, Birmensdorf, 8903, Switzerland
| | - Frank M Thomas
- Faculty of Regional and Environmental Sciences - Geobotany, University of Trier, Behringstraße 21, Trier, 54296, Germany
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10
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Giuliani R, Karki S, Covshoff S, Lin HC, Coe RA, Koteyeva NK, Quick WP, Von Caemmerer S, Furbank RT, Hibberd JM, Edwards GE, Cousins AB. Knockdown of glycine decarboxylase complex alters photorespiratory carbon isotope fractionation in Oryza sativa leaves. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2773-2786. [PMID: 30840760 PMCID: PMC6506765 DOI: 10.1093/jxb/erz083] [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: 10/23/2018] [Accepted: 02/12/2019] [Indexed: 05/07/2023]
Abstract
The influence of reduced glycine decarboxylase complex (GDC) activity on leaf atmosphere CO2 and 13CO2 exchange was tested in transgenic Oryza sativa with the GDC H-subunit knocked down in leaf mesophyll cells. Leaf measurements on transgenic gdch knockdown and wild-type plants were carried out in the light under photorespiratory and low photorespiratory conditions (i.e. 18.4 kPa and 1.84 kPa atmospheric O2 partial pressure, respectively), and in the dark. Under approximately current ambient O2 partial pressure (18.4 kPa pO2), the gdch knockdown plants showed an expected photorespiratory-deficient phenotype, with lower leaf net CO2 assimilation rates (A) than the wild-type. Additionally, under these conditions, the gdch knockdown plants had greater leaf net discrimination against 13CO2 (Δo) than the wild-type. This difference in Δo was in part due to lower 13C photorespiratory fractionation (f) ascribed to alternative decarboxylation of photorespiratory intermediates. Furthermore, the leaf dark respiration rate (Rd) was enhanced and the 13CO2 composition of respired CO2 (δ13CRd) showed a tendency to be more depleted in the gdch knockdown plants. These changes in Rd and δ13CRd were due to the amount and carbon isotopic composition of substrates available for dark respiration. These results demonstrate that impairment of the photorespiratory pathway affects leaf 13CO2 exchange, particularly the 13C decarboxylation fractionation associated with photorespiration.
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Affiliation(s)
- Rita Giuliani
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, USA
| | - Shanta Karki
- C4 Rice Center, International Rice Research Institute (IRRI), Los Baños, Philippines
| | - Sarah Covshoff
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Hsiang-Chun Lin
- C4 Rice Center, International Rice Research Institute (IRRI), Los Baños, Philippines
| | - Robert A Coe
- C4 Rice Center, International Rice Research Institute (IRRI), Los Baños, Philippines
| | - Nuria K Koteyeva
- Laboratory of Anatomy and Morphology, V.L. Komarov Botanical Institute of the Russian Academy of Sciences, St. Petersburg, Russia
| | - W Paul Quick
- C4 Rice Center, International Rice Research Institute (IRRI), Los Baños, Philippines
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Susanne Von Caemmerer
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australia
| | - Robert T Furbank
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australia
| | - Julian M Hibberd
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Gerald E Edwards
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, USA
| | - Asaph B Cousins
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, USA
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11
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Lehmann MM, Ghiasi S, George GM, Cormier MA, Gessler A, Saurer M, Werner RA. Influence of starch deficiency on photosynthetic and post-photosynthetic carbon isotope fractionations. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:1829-1841. [PMID: 30785201 PMCID: PMC6436151 DOI: 10.1093/jxb/erz045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 01/21/2019] [Indexed: 05/27/2023]
Abstract
Carbon isotope (13C) fractionations occurring during and after photosynthetic CO2 fixation shape the carbon isotope composition (δ13C) of plant material and respired CO2. However, responses of 13C fractionations to diel variation in starch metabolism in the leaf are not fully understood. Here we measured δ13C of organic matter (δ13COM), concentrations and δ13C of potential respiratory substrates, δ13C of dark-respired CO2 (δ13CR), and gas exchange in leaves of starch-deficient plastidial phosphoglucomutase (pgm) mutants and wild-type plants of four species (Arabidopsis thaliana, Mesembryanthemum crystallinum, Nicotiana sylvestris, and Pisum sativum). The strongest δ13C response to the pgm-induced starch deficiency was observed in N. sylvestris, with more negative δ13COM, δ13CR, and δ13C values for assimilates (i.e. sugars and starch) and organic acids (i.e. malate and citrate) in pgm mutants than in wild-type plants during a diel cycle. The genotype differences in δ13C values could be largely explained by differences in leaf gas exchange. In contrast, the PGM-knockout effect on post-photosynthetic 13C fractionations via the plastidic fructose-1,6-bisphosphate aldolase reaction or during respiration was small. Taken together, our results show that the δ13C variations in starch-deficient mutants are primarily explained by photosynthetic 13C fractionations and that the combination of knockout mutants and isotope analyses allows additional insights into plant metabolism.
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Affiliation(s)
- Marco M Lehmann
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zuercherstrasse, Birmensdorf, Switzerland
| | - Shiva Ghiasi
- Institute of Agricultural Sciences, ETH Zurich, Universitaetstrasse, Zurich, Switzerland
| | - Gavin M George
- Institute of Molecular Plant Biology, ETH Zurich, Universitaetstrasse, Zurich, Switzerland
| | - Marc-André Cormier
- GFZ – German Research Centre for Geosciences, Geomorphology, Organic Surface Geochemistry Lab, Telegrafenberg, Wissenschaftspark Albert Einstein, Potsdam, Germany
- University of Oxford, Department of Earth Sciences, Ocean Biogeochemistry Group, South Parks Road, Oxford, UK
| | - Arthur Gessler
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zuercherstrasse, Birmensdorf, Switzerland
- Institute of Terrestrial Ecosystems, ETH Zurich, Universitaetstrasse, Zurich, Switzerland
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zuercherstrasse, Birmensdorf, Switzerland
| | - Roland A Werner
- Institute of Agricultural Sciences, ETH Zurich, Universitaetstrasse, Zurich, Switzerland
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Fasbender L, Yáñez-Serrano AM, Kreuzwieser J, Dubbert D, Werner C. Real-time carbon allocation into biogenic volatile organic compounds (BVOCs) and respiratory carbon dioxide (CO2) traced by PTR-TOF-MS, 13CO2 laser spectroscopy and 13C-pyruvate labelling. PLoS One 2018; 13:e0204398. [PMID: 30252899 PMCID: PMC6155514 DOI: 10.1371/journal.pone.0204398] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 09/07/2018] [Indexed: 01/09/2023] Open
Abstract
Our understanding of biogenic volatile organic compound (BVOC) emissions improved substantially during the last years. Nevertheless, there are still large uncertainties of processes controlling plant carbon investment into BVOCs, of some biosynthetic pathways and their linkage to CO2 decarboxylation at central metabolic branching points. To shed more light on carbon partitioning during BVOC biosynthesis, we used an innovative approach combining δ13CO2 laser spectroscopy, high-sensitivity proton-transfer-reaction time-of-flight mass spectrometry and a multiple branch enclosure system in combination with position-specific 13C-metabolite labelling. Feeding experiments with position-specific 13C-labelled pyruvate, a central metabolite of BVOC synthesis, enabled online detection of carbon partitioning into 13C-BVOCs and respiratory 13CO2. Measurements of trace gas emissions of the Mediterranean shrub Halimium halimifolium revealed a broad range of emitted BVOCs. In general, [2-13C]-PYR was rapidly incorporated into emitted acetic acid, methyl acetate, toluene, cresol, trimethylbenzene, ethylphenol, monoterpenes and sesquiterpenes, indicating de novo BVOC biosynthesis of these compounds. In contrast, [1-13C]-pyruvate labelling substantially increased 13CO2 emissions in the light indicating C1-decarboxylation. Similar labelling patterns of methyl acetate and acetic acid suggested tightly connected biosynthetic pathways and, furthermore, there were hints of possible biosynthesis of benzenoids via the MEP-pathway. Overall, substantial CO2 emission from metabolic branching points during de novo BVOC biosynthesis indicated that decarboxylation of [1-13C]-pyruvate, as a non-mitochondrial source of CO2, seems to contribute considerably to daytime CO2 release from leaves. Our approach, combining synchronised BVOC and CO2 measurements in combination with position-specific labelling opens the door for real-time analysis tracing metabolic pathways and carbon turnover under different environmental conditions, which may enhance our understanding of regulatory mechanisms in plant carbon metabolism and BVOC biosynthesis.
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Affiliation(s)
- Lukas Fasbender
- Ecosystem Physiology, Institute of Forest Sciences, Faculty of Environment and Natural Resources, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Ana Maria Yáñez-Serrano
- Ecosystem Physiology, Institute of Forest Sciences, Faculty of Environment and Natural Resources, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Jürgen Kreuzwieser
- Ecosystem Physiology, Institute of Forest Sciences, Faculty of Environment and Natural Resources, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - David Dubbert
- Ecosystem Physiology, Institute of Forest Sciences, Faculty of Environment and Natural Resources, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Christiane Werner
- Ecosystem Physiology, Institute of Forest Sciences, Faculty of Environment and Natural Resources, Albert-Ludwigs-University Freiburg, Freiburg, Germany
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Igamberdiev AU, Bykova NV. Role of organic acids in the integration of cellular redox metabolism and mediation of redox signalling in photosynthetic tissues of higher plants. Free Radic Biol Med 2018; 122:74-85. [PMID: 29355740 DOI: 10.1016/j.freeradbiomed.2018.01.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 01/10/2018] [Accepted: 01/13/2018] [Indexed: 12/11/2022]
Abstract
Organic acids play a crucial role in numerous metabolic processes accompanied by transfer of electrons and protons and linked to the reduction/oxidation of major redox couples in plant cells, such as NAD, NADP, glutathione, and ascorbate. Fluxes through the pathways metabolizing organic acids modulate redox states in cell compartments, contribute to generation of reactive oxygen and nitrogen species, and mediate signal transduction processes. Organic acid metabolism not only functions to equilibrate the redox potential in plant cells but also to transfer redox equivalents between cell compartments supporting various metabolic processes. The most important role in this transfer belongs to different forms of malate dehydrogenase interconverting malate and oxaloacetate or forming pyruvate (malic enzymes). During photosynthesis malate serves as a major form of transfer of redox equivalents from chloroplasts to the cytosol and other compartments via the malate valve. On the other hand, mitochondria, via alterations of their redox potential, become a source of citrate that can be transported to the cytosol and support biosynthesis of amino acids. Citrate is also an important retrograde signalling compound that regulates transcription of several genes including those encoding the alternative oxidase. The alternative oxidase, which is activated by increased redox potential and by pyruvate, is, in turn, important for the maintenance of redox potential in mitochondria. The roles of organic acids in establishing redox equilibrium, supporting ionic gradients on membranes, acidification of the extracellular medium, and regulation of production of reactive oxygen and nitrogen species are discussed.
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Affiliation(s)
- Abir U Igamberdiev
- Department of Biology, Memorial University of Newfoundland, St. John's, NL, Canada A1B 3X9.
| | - Natalia V Bykova
- Morden Research and Development Centre, Agriculture and Agri-Food Canada, Morden, MB, Canada R6M 1Y5
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Ubierna N, Holloway-Phillips MM, Farquhar GD. Using Stable Carbon Isotopes to Study C 3 and C 4 Photosynthesis: Models and Calculations. Methods Mol Biol 2018; 1770:155-196. [PMID: 29978402 DOI: 10.1007/978-1-4939-7786-4_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Stable carbon isotopes are a powerful tool to study photosynthesis. Initial applications consisted of determining isotope ratios of plant biomass using mass spectrometry. Subsequently, theoretical models relating C-isotope values to gas exchange characteristics were introduced and tested against instantaneous online measurements of 13C photosynthetic discrimination. Beginning in the twenty-first century, tunable diode laser spectroscopes with sufficient precision for determining isotope mixing ratios became commercially available. This has allowed collection of large data sets, at low cost and with unprecedented temporal resolution. With more data and accompanying knowledge, it has become apparent that there is a need for increased complexity in models and calculations. This chapter describes instantaneous online measurements of 13C photosynthetic discrimination, provides recommendations for experimental setup, and presents a thorough compilation of equations needed for different applications.
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Affiliation(s)
- Nerea Ubierna
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, USA.
| | | | - Graham D Farquhar
- Research School of Biology, Australian National University, Canberra, ACT, Australia
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15
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Gao C, Yang B, Zhang D, Chen M, Tian J. Enhanced metabolic process to indole alkaloids in Clematis terniflora DC. after exposure to high level of UV-B irradiation followed by the dark. BMC PLANT BIOLOGY 2016; 16:231. [PMID: 27776479 PMCID: PMC5078895 DOI: 10.1186/s12870-016-0920-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 10/17/2016] [Indexed: 05/04/2023]
Abstract
BACKGROUND Indole alkaloids, which characteristically contain an indole nucleus, have pharmaceutical potential in a diverse range of applications. UV-B can elicit the accumulation of indole alkaloids. The indole alkaloid (6-hydroxyl-1H-indol-3-yl) carboxylic acid methyl ester with cytotoxic activity was found to accumulate in Clematis terniflora DC. leaves after exposure to high level of UV-B irradiation and the dark. However, a more in-depth analysis of the process behind this response has not yet been performed. Therefore, an integrated approach involving metabolomic, proteomic, and transcriptomic analyses is essential to detail the biosynthetic mechanisms of the regulation of indole alkaloid under binary stress. RESULTS Indole alkaloid (6-hydroxyl-1H-indol-3-yl) carboxylic acid methyl ester was found to increase 7-fold in C. terniflora leaves post-treatment with high level of UV-B irradiation followed by an incubation in the dark compared with pre-treatment. Analysis by proteomics and metabolomics indicates a decrease in photosynthesis and carbohydrate metabolism, respectively. By contrast, amino acid metabolism was activated by this binary stress, and, specifically, the genes involved in the metabolic pathway converting shikimate to L-tryptophan were concurrently upregulated. Metabolites involved in indole biosynthesis (shikimate metabolic) pathway were anthranilate, indole, and L-tryptophan, which increased 2-, 441-, and 1-fold, respectively. In addition, there was an increase of 2- and 9-fold in L-serine deaminase (L-SD) and L-tryptophan synthase activity in C. terniflora leaves after exposure to high level of UV-B irradiation and the dark. CONCLUSIONS (6-hydroxyl-1H-indol-3-yl) carboxylic acid methyl ester was found to increase in response to high level of UV-B irradiation followed by an incubation in the dark, implying that indole alkaloid biosynthesis was activated in C. terniflora leaves. Analysis of perturbations in metabolism in these leaves demonstrated that amino acid metabolism was specifically activated by this binary stress. In addition, an enhancement in serine level and L-SD activity was noted, which likely leads to an accumulation of pyruvate that, in turn, supplies shikimate metabolic pathway. The genes, metabolites, and L-tryptophan synthase activity that are involved in the metabolic pathway leading from shikimate to L-tryptophan all increased under the experimental binary stress, resulting in an enhancement of indole biosynthesis (shikimate metabolic) pathway. Therefore, the metabolic process to indole alkaloids in C. terniflora was enhanced after exposure to high level of UV-B irradiation followed by the dark.
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Affiliation(s)
- Cuixia Gao
- Institute of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Zheda Road 38, Hangzhou, 310027, China
| | - Bingxian Yang
- Institute of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Zheda Road 38, Hangzhou, 310027, China
| | - Dandan Zhang
- Institute of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Zheda Road 38, Hangzhou, 310027, China
| | - Meng Chen
- Institute of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Zheda Road 38, Hangzhou, 310027, China
| | - Jingkui Tian
- Institute of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Zheda Road 38, Hangzhou, 310027, China.
- Ministry of Education Key Laboratory for Biomedical Engineering, Zhejiang University, Hangzhou, China.
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