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Bergman ME, Kortbeek RWJ, Gutensohn M, Dudareva N. Plant terpenoid biosynthetic network and its multiple layers of regulation. Prog Lipid Res 2024; 95:101287. [PMID: 38906423 DOI: 10.1016/j.plipres.2024.101287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 06/13/2024] [Accepted: 06/17/2024] [Indexed: 06/23/2024]
Abstract
Terpenoids constitute one of the largest and most chemically diverse classes of primary and secondary metabolites in nature with an exceptional breadth of functional roles in plants. Biosynthesis of all terpenoids begins with the universal five‑carbon building blocks, isopentenyl diphosphate (IPP) and its allylic isomer dimethylallyl diphosphate (DMAPP), which in plants are derived from two compartmentally separated but metabolically crosstalking routes, the mevalonic acid (MVA) and methylerythritol phosphate (MEP) pathways. Here, we review the current knowledge on the terpenoid precursor pathways and highlight the critical hidden constraints as well as multiple regulatory mechanisms that coordinate and homeostatically govern carbon flux through the terpenoid biosynthetic network in plants.
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Affiliation(s)
- Matthew E Bergman
- Department of Biochemistry, Purdue University, West Lafayette, IN, United States; Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, United States
| | - Ruy W J Kortbeek
- Department of Biochemistry, Purdue University, West Lafayette, IN, United States; Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, United States
| | - Michael Gutensohn
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, United States
| | - Natalia Dudareva
- Department of Biochemistry, Purdue University, West Lafayette, IN, United States; Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, United States; Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN, United States.
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2
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Xu Y, Schmiege SC, Sharkey TD. The oxidative pentose phosphate pathway in photosynthesis: a tale of two shunts. THE NEW PHYTOLOGIST 2024; 242:2453-2463. [PMID: 38567702 DOI: 10.1111/nph.19730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 03/17/2024] [Indexed: 05/24/2024]
Abstract
CO2 release in the light (RL) and its presumed source, oxidative pentose phosphate pathways, were found to be insensitive to CO2 concentration. The oxidative pentose phosphate pathways form glucose 6-phosphate (G6P) shunts that bypass the nonoxidative pentose phosphate reactions of the Calvin-Benson cycle. Using adenosine diphosphate glucose and uridine diphosphate glucose as proxies for labeling of G6P in the stroma and cytosol respectively, it was found that only the cytosolic shunt was active. Uridine diphosphate glucose, a proxy for cytosolic G6P, and 6-phosphogluconate (6PG) were significantly less labeled than Calvin-Benson cycle intermediates in the light. But ADP glucose, a proxy for stromal G6P, is labeled to the same degree as Calvin-Benson cycle intermediates and much greater than 6PG. A metabolically inert pool of sedoheptulose bisphosphate can slowly equilibrate keeping the label in sedoheptulose lower than in other stromal metabolites. Finally, phosphorylation of fructose 6-phosphate (F6P) in the cytosol can allow some unlabeled carbon in cytosolic F6P to dilute label in phosphenolpyruvate. The results clearly show that there is oxidative pentose phosphate pathway activity in the cytosol that provides a shunt around the nonoxidative pentose phosphate pathway reactions of the Calvin-Benson cycle and is not strongly CO2-sensitive.
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Affiliation(s)
- Yuan Xu
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
| | - Stephanie C Schmiege
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
- Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA
- Department of Biology, Western University, London, ON, N6A 5B7, Canada
| | - Thomas D Sharkey
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
- Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
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Sharkey TD. The end game(s) of photosynthetic carbon metabolism. PLANT PHYSIOLOGY 2024; 195:67-78. [PMID: 38163636 PMCID: PMC11060661 DOI: 10.1093/plphys/kiad601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 10/27/2023] [Indexed: 01/03/2024]
Abstract
The year 2024 marks 70 years since the general outline of the carbon pathway in photosynthesis was published. Although several alternative pathways are now known, it is remarkable how many organisms use the reaction sequence described 70 yrs ago, which is now known as the Calvin-Benson cycle or variants such as the Calvin-Benson-Bassham cycle or Benson-Calvin cycle. However, once the carbon has entered the Calvin-Benson cycle and is converted to a 3-carbon sugar, it has many potential fates. This review will examine the last stages of photosynthetic metabolism in leaves. In land plants, this process mostly involves the production of sucrose provided by an endosymbiont (the chloroplast) to its host for use and transport to the rest of the plant. Photosynthetic metabolism also usually involves the synthesis of starch, which helps maintain respiration in the dark and enables the symbiont to supply sugars during both the day and night. Other end products made in the chloroplast are closely tied to photosynthetic CO2 assimilation. These include serine from photorespiration and various amino acids, fatty acids, isoprenoids, and shikimate pathway products. I also describe 2 pathways that can short circuit parts of the Calvin-Benson cycle. These final processes of photosynthetic metabolism play many important roles in plants.
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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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4
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González-Cabanelas D, Perreca E, Rohwer JM, Schmidt A, Engl T, Raguschke B, Gershenzon J, Wright LP. Deoxyxylulose 5-Phosphate Synthase Does Not Play a Major Role in Regulating the Methylerythritol 4-Phosphate Pathway in Poplar. Int J Mol Sci 2024; 25:4181. [PMID: 38673766 PMCID: PMC11049974 DOI: 10.3390/ijms25084181] [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] [Received: 02/21/2024] [Revised: 03/26/2024] [Accepted: 03/29/2024] [Indexed: 04/28/2024] Open
Abstract
The plastidic 2-C-methylerythritol 4-phosphate (MEP) pathway supplies the precursors of a large variety of essential plant isoprenoids, but its regulation is still not well understood. Using metabolic control analysis (MCA), we examined the first enzyme of this pathway, 1-deoxyxylulose 5-phosphate synthase (DXS), in multiple grey poplar (Populus × canescens) lines modified in their DXS activity. Single leaves were dynamically labeled with 13CO2 in an illuminated, climate-controlled gas exchange cuvette coupled to a proton transfer reaction mass spectrometer, and the carbon flux through the MEP pathway was calculated. Carbon was rapidly assimilated into MEP pathway intermediates and labeled both the isoprene released and the IDP+DMADP pool by up to 90%. DXS activity was increased by 25% in lines overexpressing the DXS gene and reduced by 50% in RNA interference lines, while the carbon flux in the MEP pathway was 25-35% greater in overexpressing lines and unchanged in RNA interference lines. Isoprene emission was also not altered in these different genetic backgrounds. By correlating absolute flux to DXS activity under different conditions of light and temperature, the flux control coefficient was found to be low. Among isoprenoid end products, isoprene itself was unchanged in DXS transgenic lines, but the levels of the chlorophylls and most carotenoids measured were 20-30% less in RNA interference lines than in overexpression lines. Our data thus demonstrate that DXS in the isoprene-emitting grey poplar plays only a minor part in controlling flux through the MEP pathway.
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Affiliation(s)
- Diego González-Cabanelas
- Department of Biochemistry, Max Plank Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany; (D.G.-C.); (A.S.); (B.R.); (J.G.); (L.P.W.)
| | - Erica Perreca
- Department of Biochemistry, Max Plank Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany; (D.G.-C.); (A.S.); (B.R.); (J.G.); (L.P.W.)
| | - Johann M. Rohwer
- Laboratory for Molecular Systems Biology, Department of Biochemistry, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch 7602, South Africa;
| | - Axel Schmidt
- Department of Biochemistry, Max Plank Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany; (D.G.-C.); (A.S.); (B.R.); (J.G.); (L.P.W.)
| | - Tobias Engl
- Department of Insect Symbiosis, Max Plank Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany;
| | - Bettina Raguschke
- Department of Biochemistry, Max Plank Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany; (D.G.-C.); (A.S.); (B.R.); (J.G.); (L.P.W.)
| | - Jonathan Gershenzon
- Department of Biochemistry, Max Plank Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany; (D.G.-C.); (A.S.); (B.R.); (J.G.); (L.P.W.)
| | - Louwrance P. Wright
- Department of Biochemistry, Max Plank Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany; (D.G.-C.); (A.S.); (B.R.); (J.G.); (L.P.W.)
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Clapero V, Arrivault S, Stitt M. Natural variation in metabolism of the Calvin-Benson cycle. Semin Cell Dev Biol 2024; 155:23-36. [PMID: 36959059 DOI: 10.1016/j.semcdb.2023.02.015] [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] [Received: 08/24/2022] [Revised: 02/24/2023] [Accepted: 02/24/2023] [Indexed: 03/25/2023]
Abstract
The Calvin-Benson cycle (CBC) evolved over 2 billion years ago but has been subject to massive selection due to falling atmospheric carbon dioxide, rising atmospheric oxygen and changing nutrient and water availability. In addition, large groups of organisms have evolved carbon-concentrating mechanisms (CCMs) that operate upstream of the CBC. Most previous studies of CBC diversity focused on Rubisco kinetics and regulation. Quantitative metabolite profiling provides a top-down strategy to uncover inter-species diversity in CBC operation. CBC profiles were recently published for twenty species including terrestrial C3 species, terrestrial C4 species that operate a biochemical CCM, and cyanobacteria and green algae that operate different types of biophysical CCM. Distinctive profiles were found for species with different modes of photosynthesis, revealing that evolution of the various CCMs was accompanied by co-evolution of the CBC. Diversity was also found between species that share the same mode of photosynthesis, reflecting lineage-dependent diversity of the CBC. Connectivity analysis uncovers constraints due to pathway and thermodynamic topology, and reveals that cross-species diversity in the CBC is driven by changes in the balance between regulated enzymes and in the balance between the CBC and the light reactions or end-product synthesis.
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Affiliation(s)
- Vittoria Clapero
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, Golm, D-14476 Potsdam, Germany
| | - Stéphanie Arrivault
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, Golm, D-14476 Potsdam, Germany.
| | - Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, Golm, D-14476 Potsdam, Germany
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Evans SE, Franks AE, Bergman ME, Sethna NS, Currie MA, Phillips MA. Plastid ancestors lacked a complete Entner-Doudoroff pathway, limiting plants to glycolysis and the pentose phosphate pathway. Nat Commun 2024; 15:1102. [PMID: 38321044 PMCID: PMC10847513 DOI: 10.1038/s41467-024-45384-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 01/20/2024] [Indexed: 02/08/2024] Open
Abstract
The Entner-Doudoroff (ED) pathway provides an alternative to glycolysis. It converts 6-phosphogluconate (6-PG) to glyceraldehyde-3-phosphate and pyruvate in two steps consisting of a dehydratase (EDD) and an aldolase (EDA). Here, we investigate its distribution and significance in higher plants and determine the ED pathway is restricted to prokaryotes due to the absence of EDD genes in eukaryotes. EDDs share a common origin with dihydroxy-acid dehydratases (DHADs) of the branched chain amino acid pathway (BCAA). Each dehydratase features strict substrate specificity. E. coli EDD dehydrates 6-PG to 2-keto-3-deoxy-6-phosphogluconate, while DHAD only dehydrates substrates from the BCAA pathway. Structural modeling identifies two divergent domains which account for their non-overlapping substrate affinities. Coupled enzyme assays confirm only EDD participates in the ED pathway. Plastid ancestors lacked EDD but transferred metabolically promiscuous EDA, which explains the absence of the ED pathway from the Viridiplantae and sporadic persistence of EDA genes across the plant kingdom.
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Affiliation(s)
- Sonia E Evans
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Anya E Franks
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Matthew E Bergman
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Nasha S Sethna
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Mark A Currie
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
- Department of Biology, University of Toronto-Mississauga, Mississauga, ON, L5L 1C6, Canada
| | - Michael A Phillips
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada.
- Department of Biology, University of Toronto-Mississauga, Mississauga, ON, L5L 1C6, Canada.
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Oku H, Iqbal A, Oogai S, Inafuku M, Mutanda I. Relationship between Cumulative Temperature and Light Intensity and G93 Parameters of Isoprene Emission for the Tropical Tree Ficus septica. PLANTS (BASEL, SWITZERLAND) 2024; 13:243. [PMID: 38256797 PMCID: PMC10820733 DOI: 10.3390/plants13020243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 01/24/2024]
Abstract
The most widely used isoprene emission algorithm, G93 formula, estimates instantaneous leaf-level isoprene emission using the basal emission factor and light and temperature dependency parameters. The G93 parameters have been suggested to show variation depending on past weather conditions, but no study has closely examined the relationship between past meteorological data and the algorithm parameters. Here, to examine the influence of the past weather on these parameters, we monitored weather conditions, G93 parameters, isoprene synthase transcripts and protein levels, and MEP pathway metabolites in the tropical tree Ficus septica for 12 days and analyzed their relationship with cumulative temperature and light intensity. Plants were illuminated with varying (ascending and descending) light regimes, and our previously developed Ping-Pong optimization method was used to parameterize G93. The cumulative temperature of the past 5 and 7 days positively correlated with CT2 and α, respectively, while the cumulative light intensity of the past 10 days showed the highest negative correlation with α. Concentrations of MEP pathway metabolites and IspS gene expression increased with increasing cumulative temperature. At best, the cumulative temperature of the past 2 days positively correlated with the MEP pathway metabolites and IspS gene expression, while these factors showed a biphasic positive and negative correlation with cumulative light intensity. Optimized G93 captured well the temperature and light dependency of isoprene emission at the beginning of the experiment; however, its performance significantly decreased for the latter stages of the experimental duration, especially for the descending phase. This was successfully improved through separate optimization of the ascending and descending phases, emphasizing the importance of the optimization of formula parameters and model improvement. These results have important implications for the improvement of isoprene emission algorithms, particularly under the predicted increase in future global temperatures.
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Affiliation(s)
- Hirosuke Oku
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa 903-0213, Japan; (H.O.); (S.O.)
| | - Asif Iqbal
- The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan;
| | - Shigeki Oogai
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa 903-0213, Japan; (H.O.); (S.O.)
| | - Masashi Inafuku
- Faculty of Agriculture, University of the Ryukyus, Okinawa 903-0213, Japan;
| | - Ishmael Mutanda
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa 903-0213, Japan; (H.O.); (S.O.)
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Sahu A, Mostofa MG, Weraduwage SM, Sharkey TD. Hydroxymethylbutenyl diphosphate accumulation reveals MEP pathway regulation for high CO 2-induced suppression of isoprene emission. Proc Natl Acad Sci U S A 2023; 120:e2309536120. [PMID: 37782800 PMCID: PMC10576107 DOI: 10.1073/pnas.2309536120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/24/2023] [Indexed: 10/04/2023] Open
Abstract
Isoprene is emitted by some plants and is the most abundant biogenic hydrocarbon entering the atmosphere. Multiple studies have elucidated protective roles of isoprene against several environmental stresses, including high temperature, excessive ozone, and herbivory attack. However, isoprene emission adversely affects atmospheric chemistry by contributing to ozone production and aerosol formation. Thus, understanding the regulation of isoprene emission in response to varying environmental conditions, for example, elevated CO2, is critical to comprehend how plants will respond to climate change. Isoprene emission decreases with increasing CO2 concentration; however, the underlying mechanism of this response is currently unknown. We demonstrated that high-CO2-mediated suppression of isoprene emission is independent of photosynthesis and light intensity, but it is reduced with increasing temperature. Furthermore, we measured methylerythritol 4-phosphate (MEP) pathway metabolites in poplar leaves harvested at ambient and high CO2 to identify why isoprene emission is reduced under high CO2. We found that hydroxymethylbutenyl diphosphate (HMBDP) was increased and dimethylallyl diphosphate (DMADP) decreased at high CO2. This implies that high CO2 impeded the conversion of HMBDP to DMADP, possibly through the inhibition of HMBDP reductase activity, resulting in reduced isoprene emission. We further demonstrated that although this phenomenon appears similar to abscisic acid (ABA)-dependent stomatal regulation, it is unrelated as ABA treatment did not alter the effect of elevated CO2 on the suppression of isoprene emission. Thus, this study provides a comprehensive understanding of the regulation of the MEP pathway and isoprene emission in the face of increasing CO2.
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Affiliation(s)
- Abira Sahu
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing48824, MI
- Plant Resilience Institute, Michigan State University, East Lansing48824, MI
| | - Mohammad Golam Mostofa
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing48824, MI
- Plant Resilience Institute, Michigan State University, East Lansing48824, MI
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing48824, MI
| | - Sarathi M. Weraduwage
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing48824, MI
- Plant Resilience Institute, Michigan State University, East Lansing48824, MI
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing48824, MI
- Department of Biology and Biochemistry, Bishop’s University, SherbrookeJIE0L3, QC, Canada
| | - Thomas D. Sharkey
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing48824, MI
- Plant Resilience Institute, Michigan State University, East Lansing48824, MI
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing48824, MI
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Shi H, Ernst E, Heinzel N, McCorkle S, Rolletschek H, Borisjuk L, Ortleb S, Martienssen R, Shanklin J, Schwender J. Mechanisms of metabolic adaptation in the duckweed Lemna gibba: an integrated metabolic, transcriptomic and flux analysis. BMC PLANT BIOLOGY 2023; 23:458. [PMID: 37789269 PMCID: PMC10546790 DOI: 10.1186/s12870-023-04480-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 09/20/2023] [Indexed: 10/05/2023]
Abstract
BACKGROUND Duckweeds are small, rapidly growing aquatic flowering plants. Due to their ability for biomass production at high rates they represent promising candidates for biofuel feedstocks. Duckweeds are also excellent model organisms because they can be maintained in well-defined liquid media, usually reproduce asexually, and because genomic resources are becoming increasingly available. To demonstrate the utility of duckweed for integrated metabolic studies, we examined the metabolic adaptation of growing Lemna gibba cultures to different nutritional conditions. RESULTS To establish a framework for quantitative metabolic research in duckweeds we derived a central carbon metabolism network model of Lemna gibba based on its draft genome. Lemna gibba fronds were grown with nitrate or glutamine as nitrogen source. The two conditions were compared by quantification of growth kinetics, metabolite levels, transcript abundance, as well as by 13C-metabolic flux analysis. While growing with glutamine, the fronds grew 1.4 times faster and accumulated more protein and less cell wall components compared to plants grown on nitrate. Characterization of photomixotrophic growth by 13C-metabolic flux analysis showed that, under both metabolic growth conditions, the Calvin-Benson-Bassham cycle and the oxidative pentose-phosphate pathway are highly active, creating a futile cycle with net ATP consumption. Depending on the nitrogen source, substantial reorganization of fluxes around the tricarboxylic acid cycle took place, leading to differential formation of the biosynthetic precursors of the Asp and Gln families of proteinogenic amino acids. Despite the substantial reorganization of fluxes around the tricarboxylic acid cycle, flux changes could largely not be associated with changes in transcripts. CONCLUSIONS Through integrated analysis of growth rate, biomass composition, metabolite levels, and metabolic flux, we show that Lemna gibba is an excellent system for quantitative metabolic studies in plants. Our study showed that Lemna gibba adjusts to different nitrogen sources by reorganizing central metabolism. The observed disconnect between gene expression regulation and metabolism underscores the importance of metabolic flux analysis as a tool in such studies.
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Affiliation(s)
- Hai Shi
- Biology Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Evan Ernst
- Cold Spring Harbor Laboratory, 1 Bungtown Rd, Cold Spring Harbor, NY, 11724, USA
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY, 11724, USA
| | - Nicolas Heinzel
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466, Seeland OT Gatersleben, Germany
| | - Sean McCorkle
- Brookhaven National Laboratory, Computational Science Initiative, Upton, NY, 11973, USA
| | - Hardy Rolletschek
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466, Seeland OT Gatersleben, Germany
| | - Ljudmilla Borisjuk
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466, Seeland OT Gatersleben, Germany
| | - Stefan Ortleb
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466, Seeland OT Gatersleben, Germany
| | - Robert Martienssen
- Cold Spring Harbor Laboratory, 1 Bungtown Rd, Cold Spring Harbor, NY, 11724, USA
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY, 11724, USA
| | - John Shanklin
- Biology Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Jorg Schwender
- Biology Department, Brookhaven National Laboratory, Upton, NY, 11973, USA.
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10
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Iqbal MA, Miyamoto K, Yumoto E, Oogai S, Mutanda I, Inafuku M, Oku H. Relationship between seasonal variation in isoprene emission and plant hormone profiles in the tropical plant Ficus septica. PLANT BIOLOGY (STUTTGART, GERMANY) 2023; 25:981-993. [PMID: 37565537 DOI: 10.1111/plb.13565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 07/19/2023] [Indexed: 08/12/2023]
Abstract
In Ficus septica, the short-term control of isoprene production and, therefore, isoprene emission has been linked to the hormone balance between auxin (IAA) and jasmonic acid (JA). However, the relationship between long-term changes in isoprene emission and that of plant hormones remains unknown. This study tracked isoprene emissions from F. septica leaves, plant hormone concentrations and signalling gene expression, MEP pathway metabolite concentrations, and related enzyme gene expression for 1 year in the field to better understand the role of plant hormones and their long-term control. Seasonality of isoprenes was mainly driven by temperature- and light-dependent variations in substrate availability through the MEP route, as well as transcriptional and post-transcriptional control of isoprene synthase (IspS). Isoprene emissions are seasonally correlated with plant hormone levels. This was especially evident in the cytokinin profiles, which decreased in summer and increased in winter. Only 4-hydroxy-3-methylbut-2-butenyl-4-diphosphate (HMBDP) exhibited a positive connection with cytokinins among the MEP metabolites examined, suggesting that HMBDP and its biosynthetic enzyme, HMBDP synthase (HDS), play a role in channelling of MEP pathway metabolites to cytokinin production. Thus, it is probable that cytokinins have potential feed-forward regulation of isoprene production. Under long-term natural conditions, the hormonal balance of IAA/JA-Ile was not associated with IspS transcripts or isoprene emissions. This study builds on prior work by revealing differences between short- and long-term hormonal modulation of isoprene emissions in the tropical tree F. septica.
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Affiliation(s)
- M A Iqbal
- The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan
| | - K Miyamoto
- Department of Biosciences, Teikyo University, Utsunomiya, Tochigi, Japan
| | - E Yumoto
- Advanced Instrumental Analysis Center, Teikyo University, Tochigi, Japan
| | - S Oogai
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan
| | - I Mutanda
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu, China
| | - M Inafuku
- Faculty of Agriculture, University of the Ryukyus, Okinawa, Japan
| | - H Oku
- The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan
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11
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Schmiege SC, Sharkey TD, Walker B, Hammer J, Way DA. Laisk measurements in the nonsteady state: Tests in plants exposed to warming and variable CO2 concentrations. PLANT PHYSIOLOGY 2023; 193:1045-1057. [PMID: 37232396 PMCID: PMC10517191 DOI: 10.1093/plphys/kiad305] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/28/2023] [Accepted: 04/29/2023] [Indexed: 05/27/2023]
Abstract
Light respiration (RL) is an important component of plant carbon balance and a key parameter in photosynthesis models. RL is often measured using the Laisk method, a gas exchange technique that is traditionally employed under steady-state conditions. However, a nonsteady-state dynamic assimilation technique (DAT) may allow for more rapid Laisk measurements. In 2 studies, we examined the efficacy of DAT for estimating RL and the parameter Ci* (the intercellular CO2 concentration where Rubisco's oxygenation velocity is twice its carboxylation velocity), which is also derived from the Laisk technique. In the first study, we compared DAT and steady-state RL and Ci* estimates in paper birch (Betula papyrifera) growing under control and elevated temperature and CO2 concentrations. In the second, we compared DAT-estimated RL and Ci* in hybrid poplar (Populus nigra L. × P. maximowiczii A. Henry "NM6") exposed to high or low CO2 concentration pre-treatments. The DAT and steady-state methods provided similar RL estimates in B. papyrifera, and we found little acclimation of RL to temperature or CO2; however, Ci* was higher when measured with DAT compared to steady-state methods. These Ci* differences were amplified by the high or low CO2 pre-treatments. We propose that changes in the export of glycine from photorespiration may explain these apparent differences in Ci*.
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Affiliation(s)
- Stephanie C Schmiege
- Plant Resilience Institute, Michigan State University, East Lansing, MI 48824, USA
- Department of Biology, Western University, London, Ontario N6A 5B7, Canada
| | - Thomas D Sharkey
- Plant Resilience Institute, Michigan State University, East Lansing, MI 48824, USA
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Berkley Walker
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Julia Hammer
- Department of Biology, Western University, London, Ontario N6A 5B7, Canada
| | - Danielle A Way
- Department of Biology, Western University, London, Ontario N6A 5B7, Canada
- Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia
- Nicholas School of the Environment, Duke University, Durham, NC 27710, USA
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, NY 11973, USA
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12
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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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13
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Wieloch T. High atmospheric CO 2 concentration causes increased respiration by the oxidative pentose phosphate pathway in chloroplasts. THE NEW PHYTOLOGIST 2022; 235:1310-1314. [PMID: 35575022 PMCID: PMC9546095 DOI: 10.1111/nph.18226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/08/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Thomas Wieloch
- Department of Medical Biochemistry and BiophysicsUmeå UniversityUmeå90187Sweden
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14
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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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15
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Wieloch T, Sharkey TD. Compartment-specific energy requirements of photosynthetic carbon metabolism in Camelina sativa leaves. PLANTA 2022; 255:103. [PMID: 35415783 PMCID: PMC9005430 DOI: 10.1007/s00425-022-03884-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 03/25/2022] [Indexed: 06/14/2023]
Abstract
The oxidative pentose phosphate pathway provides cytosolic NADPH yet reduces carbon and energy use efficiency. Repressing this pathway and introducing cytosolic NADPH-dependent malate dehydrogenase may increase crop yields by ≈5%. Detailed knowledge about plant energy metabolism may aid crop improvements. Using published estimates of flux through central carbon metabolism, we phenotype energy metabolism in illuminated Camelina sativa leaves (grown at 22 °C, 500 µmol photons m-2 s-1) and report several findings. First, the oxidative pentose phosphate pathway (OPPP) transfers 3.3% of the NADPH consumed in the Calvin-Benson cycle to the cytosol. NADPH supply proceeds at about 10% of the rate of net carbon assimilation. However, concomitantly respired CO2 accounts for 4.8% of total rubisco activity. Hence, 4.8% of the flux through the Calvin-Benson cycle and photorespiration is spent on supplying cytosolic NADPH, a significant investment. Associated energy requirements exceed the energy output of the OPPP. Thus, autotrophic carbon metabolism is not simply optimised for flux into carbon sinks but sacrifices carbon and energy use efficiency to support cytosolic energy metabolism. To reduce these costs, we suggest bioengineering plants with a repressed cytosolic OPPP, and an inserted cytosolic NADPH-dependent malate dehydrogenase tuned to compensate for the loss in OPPP activity (if required). Second, sucrose cycling is a minor investment in overall leaf energy metabolism but a significant investment in cytosolic energy metabolism. Third, leaf energy balancing strictly requires oxidative phosphorylation, cofactor export from chloroplasts, and peroxisomal NADH import. Fourth, mitochondria are energetically self-sufficient. Fifth, carbon metabolism has an ATP/NADPH demand ratio of 1.52 which is met if ≤ 21.7% of whole electron flux is cyclic. Sixth, electron transport has a photon use efficiency of ≥ 62%. Last, we discuss interactions between the OPPP and the cytosolic oxidation-reduction cycle in supplying leaf cytosolic NADPH.
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Affiliation(s)
- Thomas Wieloch
- Department of Medical Biochemistry and Biophysics, KB. H6, Umeå University, 901 87, Umeå, Sweden.
| | - Thomas David Sharkey
- Department of Energy, Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
- Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA
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16
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Evans SE, Duggan P, Bergman ME, Cobo-López D, Davis B, Bajwa I, Phillips MA. Design and fabrication of an improved dynamic flow cuvette for 13CO 2 labeling in Arabidopsis plants. PLANT METHODS 2022; 18:40. [PMID: 35346271 PMCID: PMC8958768 DOI: 10.1186/s13007-022-00873-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 03/11/2022] [Indexed: 05/22/2023]
Abstract
BACKGROUND Stable isotope labeling is a non-invasive, sensitive means of monitoring metabolic flux in plants. The most physiologically meaningful information is obtained from experiments that take advantage of the natural photosynthetic carbon assimilation pathway to introduce a traceable marker with minimal effects on the physiology of the organism. The fundamental substrate in isotopic labeling experiments is 13CO2, which can reveal the earliest events in carbon assimilation and realistically portray downstream metabolism when administered under conditions suitable for making kinetic inferences. Efforts to improve the accuracy and resolution of whole plant labeling techniques have focused on improvements in environmental control, air flow characteristics, and harvesting methods. RESULTS Here we present a dynamic flow cuvette designed for single Arabidopsis thaliana labeling experiments. We have also verified its suitability for labeling Nicotiana benthamiana and essential oils in Pelargonium graveolens. Complete plans for fabrication of this device are included. The design includes three important innovations. First, uniform, circular air flow over the rosette surface is accomplished by a fan and deflector that creates a mini-cyclone effect within the chamber interior. Second, a network of circulating canals connected to a water bath provides temperature control to within ± 0.1 ºC under variable irradiance, humidity, and air flow conditions. When photosynthetically active radiation (PAR) was varied over a range of 1000 μEinsteins m-2 s-1 with no adjustment to the external temperature control system, the abaxial leaf temperature changed by < 3 ºC/1000 PAR. Third, the device is fully compatible with liquid nitrogen quenching of metabolic activity without perturbation of the light environment. For short labeling experiments (< 10 s), the most critical variable is the half-life (t1/2) of the atmosphere within the chamber, which determines the maximum resolution of the labeling system. Using an infrared gas analyzer, we monitored the atmospheric half-life during the transition from 12CO2 to 13CO2 air at different flow rates and determined that 3.5 L min-1 is the optimal flow rate to initiate labeling (t1/2 ~ 5 s). Under these conditions, we observed linear incorporation of 13C into triose phosphate with labeling times as short as 5 s. CONCLUSIONS Advances in our ability to conduct short term labeling experiments are critical to understanding of the rates and control of the earliest steps in plant metabolism. Precise kinetic measurements in whole plants using 13CO2 inform metabolic models and reveal control points that can be exploited in agricultural or biotechnological contexts. The dynamic labeling cuvette presented here is suitable for studying early events in carbon assimilation and provides high resolution kinetic data for studies of metabolism in intact plants under physiologically realistic scenarios.
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Affiliation(s)
- Sonia E Evans
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Peter Duggan
- Academic Machine Shop, University of Toronto-Mississauga, Mississauga, Canada
| | - Matthew E Bergman
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Daniela Cobo-López
- Department of Biology, University of Toronto-Mississauga, Mississauga, ON, L5L 1C6, Canada
| | - Benjamin Davis
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Ibadat Bajwa
- Department of Biology, University of Toronto-Mississauga, Mississauga, ON, L5L 1C6, Canada
| | - Michael A Phillips
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada.
- Department of Biology, University of Toronto-Mississauga, Mississauga, ON, L5L 1C6, Canada.
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17
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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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18
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Borghi GL, Arrivault S, Günther M, Barbosa Medeiros D, Dell’Aversana E, Fusco GM, Carillo P, Ludwig M, Fernie AR, Lunn JE, Stitt M. Metabolic profiles in C3, C3-C4 intermediate, C4-like, and C4 species in the genus Flaveria. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1581-1601. [PMID: 34910813 PMCID: PMC8890617 DOI: 10.1093/jxb/erab540] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 12/14/2021] [Indexed: 05/22/2023]
Abstract
C4 photosynthesis concentrates CO2 around Rubisco in the bundle sheath, favouring carboxylation over oxygenation and decreasing photorespiration. This complex trait evolved independently in >60 angiosperm lineages. Its evolution can be investigated in genera such as Flaveria (Asteraceae) that contain species representing intermediate stages between C3 and C4 photosynthesis. Previous studies have indicated that the first major change in metabolism probably involved relocation of glycine decarboxylase and photorespiratory CO2 release to the bundle sheath and establishment of intercellular shuttles to maintain nitrogen stoichiometry. This was followed by selection for a CO2-concentrating cycle between phosphoenolpyruvate carboxylase in the mesophyll and decarboxylases in the bundle sheath, and relocation of Rubisco to the latter. We have profiled 52 metabolites in nine Flaveria species and analysed 13CO2 labelling patterns for four species. Our results point to operation of multiple shuttles, including movement of aspartate in C3-C4 intermediates and a switch towards a malate/pyruvate shuttle in C4-like species. The malate/pyruvate shuttle increases from C4-like to complete C4 species, accompanied by a rise in ancillary organic acid pools. Our findings support current models and uncover further modifications of metabolism along the evolutionary path to C4 photosynthesis in the genus Flaveria.
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Affiliation(s)
- Gian Luca Borghi
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Stéphanie Arrivault
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
- Correspondence:
| | - Manuela Günther
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - David Barbosa Medeiros
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Emilia Dell’Aversana
- Universitá degli Studi della Campania, Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Via Vivaldi 43, 81100 Caserta, Italy
| | - Giovanna Marta Fusco
- Universitá degli Studi della Campania, Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Via Vivaldi 43, 81100 Caserta, Italy
| | - Petronia Carillo
- Universitá degli Studi della Campania, Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Via Vivaldi 43, 81100 Caserta, Italy
| | - Martha Ludwig
- The University of Western Australia, School of Molecular Sciences, 35 Stirling Highway, 6009 Perth, Australia
| | - Alisdair R Fernie
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - John E Lunn
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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19
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Weraduwage SM, Rasulov B, Sahu A, Niinemets Ü, Sharkey TD. Isoprene measurements to assess plant hydrocarbon emissions and the methylerythritol pathway. Methods Enzymol 2022; 676:211-237. [DOI: 10.1016/bs.mie.2022.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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20
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Chu KL, Koley S, Jenkins LM, Bailey SR, Kambhampati S, Foley K, Arp JJ, Morley SA, Czymmek KJ, Bates PD, Allen DK. Metabolic flux analysis of the non-transitory starch tradeoff for lipid production in mature tobacco leaves. Metab Eng 2022; 69:231-248. [PMID: 34920088 PMCID: PMC8761171 DOI: 10.1016/j.ymben.2021.12.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 10/12/2021] [Accepted: 12/11/2021] [Indexed: 12/19/2022]
Abstract
The metabolic plasticity of tobacco leaves has been demonstrated via the generation of transgenic plants that can accumulate over 30% dry weight as triacylglycerols. In investigating the changes in carbon partitioning in these high lipid-producing (HLP) leaves, foliar lipids accumulated stepwise over development. Interestingly, non-transient starch was observed to accumulate with plant age in WT but not HLP leaves, with a drop in foliar starch concurrent with an increase in lipid content. The metabolic carbon tradeoff between starch and lipid was studied using 13CO2-labeling experiments and isotopically nonstationary metabolic flux analysis, not previously applied to the mature leaves of a crop. Fatty acid synthesis was investigated through assessment of acyl-acyl carrier proteins using a recently derived quantification method that was extended to accommodate isotopic labeling. Analysis of labeling patterns and flux modeling indicated the continued production of unlabeled starch, sucrose cycling, and a significant contribution of NADP-malic enzyme to plastidic pyruvate production for the production of lipids in HLP leaves, with the latter verified by enzyme activity assays. The results suggest an inherent capacity for a developmentally regulated carbon sink in tobacco leaves and may in part explain the uniquely successful leaf lipid engineering efforts in this crop.
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Affiliation(s)
- Kevin L Chu
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Somnath Koley
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Lauren M Jenkins
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Sally R Bailey
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA; United States Department of Agriculture-Agriculture Research Service, Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | | | - Kevin Foley
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Jennifer J Arp
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Stewart A Morley
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA; United States Department of Agriculture-Agriculture Research Service, Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Kirk J Czymmek
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Philip D Bates
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164-6340, USA
| | - Doug K Allen
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA; United States Department of Agriculture-Agriculture Research Service, Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA.
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21
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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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22
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Stitt M, Luca Borghi G, Arrivault S. Targeted metabolite profiling as a top-down approach to uncover interspecies diversity and identify key conserved operational features in the Calvin-Benson cycle. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:5961-5986. [PMID: 34473300 PMCID: PMC8411860 DOI: 10.1093/jxb/erab291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/21/2021] [Indexed: 05/02/2023]
Abstract
Improving photosynthesis is a promising avenue to increase crop yield. This will be aided by better understanding of natural variance in photosynthesis. Profiling of Calvin-Benson cycle (CBC) metabolites provides a top-down strategy to uncover interspecies diversity in CBC operation. In a study of four C4 and five C3 species, principal components analysis separated C4 species from C3 species and also separated different C4 species. These separations were driven by metabolites that reflect known species differences in their biochemistry and pathways. Unexpectedly, there was also considerable diversity between the C3 species. Falling atmospheric CO2 and changing temperature, nitrogen, and water availability have driven evolution of C4 photosynthesis in multiple lineages. We propose that analogous selective pressures drove lineage-dependent evolution of the CBC in C3 species. Examples of species-dependent variation include differences in the balance between the CBC and the light reactions, and in the balance between regulated steps in the CBC. Metabolite profiles also reveal conserved features including inactivation of enzymes in low irradiance, and maintenance of CBC metabolites at relatively high levels in the absence of net CO2 fixation. These features may be important for photosynthetic efficiency in low light, fluctuating irradiance, and when stomata close due to low water availability.
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Affiliation(s)
- Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Gian Luca Borghi
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Stéphanie Arrivault
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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23
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Sharkey TD. Pentose Phosphate Pathway Reactions in Photosynthesizing Cells. Cells 2021; 10:cells10061547. [PMID: 34207480 PMCID: PMC8234502 DOI: 10.3390/cells10061547] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 06/11/2021] [Accepted: 06/11/2021] [Indexed: 12/14/2022] Open
Abstract
The pentose phosphate pathway (PPP) is divided into an oxidative branch that makes pentose phosphates and a non-oxidative branch that consumes pentose phosphates, though the non-oxidative branch is considered reversible. A modified version of the non-oxidative branch is a critical component of the Calvin–Benson cycle that converts CO2 into sugar. The reaction sequence in the Calvin–Benson cycle is from triose phosphates to pentose phosphates, the opposite of the typical direction of the non-oxidative PPP. The photosynthetic direction is favored by replacing the transaldolase step of the normal non-oxidative PPP with a second aldolase reaction plus sedoheptulose-1,7-bisphosphatase. This can be considered an anabolic version of the non-oxidative PPP and is found in a few situations other than photosynthesis. In addition to the strong association of the non-oxidative PPP with photosynthesis metabolism, there is recent evidence that the oxidative PPP reactions are also important in photosynthesizing cells. These reactions can form a shunt around the non-oxidative PPP section of the Calvin–Benson cycle, consuming three ATP per glucose 6-phosphate consumed. A constitutive operation of this shunt occurs in the cytosol and gives rise to an unusual labeling pattern of photosynthetic metabolites while an inducible shunt in the stroma may occur in response to stress.
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Affiliation(s)
- Thomas D Sharkey
- MSU-DOE Plant Research Laboratory, Plant Resilience Institute, Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48823, USA
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24
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Xu Y, Fu X, Sharkey TD, Shachar-Hill Y, Walker ABJ. The metabolic origins of non-photorespiratory CO2 release during photosynthesis: a metabolic flux analysis. PLANT PHYSIOLOGY 2021; 186:297-314. [PMID: 33591309 PMCID: PMC8154043 DOI: 10.1093/plphys/kiab076] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 01/16/2021] [Indexed: 05/02/2023]
Abstract
Respiration in the light (RL) releases CO2 in photosynthesizing leaves and is a phenomenon that occurs independently from photorespiration. Since RL lowers net carbon fixation, understanding RL could help improve plant carbon-use efficiency and models of crop photosynthesis. Although RL was identified more than 75 years ago, its biochemical mechanisms remain unclear. To identify reactions contributing to RL, we mapped metabolic fluxes in photosynthesizing source leaves of the oilseed crop and model plant camelina (Camelina sativa). We performed a flux analysis using isotopic labeling patterns of central metabolites during 13CO2 labeling time course, gas exchange, and carbohydrate production rate experiments. To quantify the contributions of multiple potential CO2 sources with statistical and biological confidence, we increased the number of metabolites measured and reduced biological and technical heterogeneity by using single mature source leaves and quickly quenching metabolism by directly injecting liquid N2; we then compared the goodness-of-fit between these data and data from models with alternative metabolic network structures and constraints. Our analysis predicted that RL releases 5.2 μmol CO2 g-1 FW h-1 of CO2, which is relatively consistent with a value of 9.3 μmol CO2 g-1 FW h-1 measured by CO2 gas exchange. The results indicated that ≤10% of RL results from TCA cycle reactions, which are widely considered to dominate RL. Further analysis of the results indicated that oxidation of glucose-6-phosphate to pentose phosphate via 6-phosphogluconate (the G6P/OPP shunt) can account for >93% of CO2 released by RL.
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Affiliation(s)
- Yuan Xu
- Department of Plant Biology, Michigan State University, Michigan 48824, USA
| | - Xinyu Fu
- Department of Plant Biology, Michigan State University, Michigan 48824, USA
- Department of Energy-Plant Research Laboratory, Michigan State University, Michigan 48824, USA
| | - Thomas D Sharkey
- Department of Energy-Plant Research Laboratory, Michigan State University, Michigan 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, Michigan 48824, USA
| | - Yair Shachar-Hill
- Department of Plant Biology, Michigan State University, Michigan 48824, USA
| | - and Berkley J Walker
- Department of Plant Biology, Michigan State University, Michigan 48824, USA
- Department of Energy-Plant Research Laboratory, Michigan State University, Michigan 48824, USA
- Author for communication:
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Bergman ME, González-Cabanelas D, Wright LP, Walker BJ, Phillips MA. Isotope ratio-based quantification of carbon assimilation highlights the role of plastidial isoprenoid precursor availability in photosynthesis. PLANT METHODS 2021; 17:32. [PMID: 33781281 PMCID: PMC8008545 DOI: 10.1186/s13007-021-00731-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/13/2021] [Indexed: 05/22/2023]
Abstract
BACKGROUND We report a method to estimate carbon assimilation based on isotope ratio-mass spectrometry (IRMS) of 13CO2 labeled plant tissue. Photosynthetic carbon assimilation is the principal experimental observable which integrates important aspects of primary plant metabolism. It is traditionally measured through gas exchange. Despite its centrality in plant research, gas exchange performs poorly with rosette growth habits typical of Arabidopsis thaliana, mutant lines with limited biomass, and accounts poorly for leaf shading. RESULTS IRMS-based carbon assimilation values from plants labeled at different light intensities were compared to those obtained by gas exchange, and the two methods yielded similar values. Using this method, we observed a strong correlation between 13C content and labeling time (R2 = 0.999) for 158 wild-type plants labeled for 6 to 42 min. Plants cultivated under different light regimes showed a linear response with respect to carbon assimilation, varying from 7.38 nmol 13C mg-1 leaf tissue min-1 at 80 PAR to 19.27 nmol 13C mg-1 leaf tissue min-1 at 500 PAR. We applied this method to examine the link between inhibition of the 2C-methyl-D-erythritol-4-phosphate (MEP) pathway and suppression of photosynthesis. A significant decrease in carbon assimilation was observed when metabolic activity in the MEP pathway was compromised by mutation or herbicides targeting the MEP pathway. Mutants affected in MEP pathway genes 1-DEOXY-D-XYLULOSE 5-PHOSPHATE SYNTHASE (DXS) or 1-HYDROXY-2-METHYL-2-(E)-BUTENYL 4-DIPHOSPHATE SYNTHASE (HDS) showed assimilation rates 36% and 61% lower than wild type. Similarly, wild type plants treated with the MEP pathway inhibitors clomazone or fosmidomycin showed reductions of 52% and 43%, respectively, while inhibition of the analogous mevalonic acid pathway, which supplies the same isoprenoid intermediates in the cytosol, did not, suggesting inhibition of photosynthesis was specific to disruption of the MEP pathway. CONCLUSIONS This method provides an alternative to gas exchange that offers several advantages: resilience to differences in leaf overlap, measurements based on tissue mass rather than leaf surface area, and compatibility with mutant Arabidopsis lines which are not amenable to gas exchange measurements due to low biomass and limited leaf surface area. It is suitable for screening large numbers of replicates simultaneously as well as post-hoc analysis of previously labeled plant tissue and is complementary to downstream detection of isotopic label in targeted metabolite pools.
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Affiliation(s)
- Matthew E Bergman
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | | | - Louwrance P Wright
- Zeiselhof Research Farm, Menlo Park, P.O. Box 35984, Pretoria, 0102, South Africa
| | - Berkley J Walker
- Department of Energy, Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
- Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Michael A Phillips
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada.
- Department of Biology, University of Toronto-Mississauga, Mississauga, ON, L5L 1C6, Canada.
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Leaf isoprene emission as a trait that mediates the growth-defense tradeoff in the face of climate stress. Oecologia 2021; 197:885-902. [PMID: 33420520 DOI: 10.1007/s00442-020-04813-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 12/01/2020] [Indexed: 12/27/2022]
Abstract
Plant isoprene emissions are known to contribute to abiotic stress tolerance, especially during episodes of high temperature and drought, and during cellular oxidative stress. Recent studies have shown that genetic transformations to add or remove isoprene emissions cause a cascade of cellular modifications that include known signaling pathways, and interact to remodel adaptive growth-defense tradeoffs. The most compelling evidence for isoprene signaling is found in the shikimate and phenylpropanoid pathways, which produce salicylic acid, alkaloids, tannins, anthocyanins, flavonols and other flavonoids; all of which have roles in stress tolerance and plant defense. Isoprene also influences key gene expression patterns in the terpenoid biosynthetic pathways, and the jasmonic acid, gibberellic acid and cytokinin signaling networks that have important roles in controlling inducible defense responses and influencing plant growth and development, particularly following defoliation. In this synthesis paper, using past studies of transgenic poplar, tobacco and Arabidopsis, we present the evidence for isoprene acting as a metabolite that coordinates aspects of cellular signaling, resulting in enhanced chemical defense during periods of climate stress, while minimizing costs to growth. This perspective represents a major shift in our thinking away from direct effects of isoprene, for example, by changing membrane properties or quenching ROS, to indirect effects, through changes in gene expression and protein abundances. Recognition of isoprene's role in the growth-defense tradeoff provides new perspectives on evolution of the trait, its contribution to plant adaptation and resilience, and the ecological niches in which it is most effective.
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