The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform
Paul F South - One of the best experts on this subject based on the ideXlab platform.
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optimizing Photorespiration for improved crop productivity
Journal of Integrative Plant Biology, 2018Co-Authors: Paul F South, Amanda P Cavanagh, Patricia E Lopezcalcagno, Christine A RainesAbstract:: In C3 plants, Photorespiration is an energy-expensive process, including the oxygenation of ribulose-1,5-bisphosphate (RuBP) by ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) and the ensuing multi-organellar photorespiratory pathway required to recycle the toxic byproducts and recapture a portion of the fixed carbon. Photorespiration significantly impacts crop productivity through reducing yields in C3 crops by as much as 50% under severe conditions. Thus, reducing the flux through, or improving the efficiency of Photorespiration has the potential of large improvements in C3 crop productivity. Here, we review an array of approaches intended to engineer Photorespiration in a range of plant systems with the goal of increasing crop productivity. Approaches include optimizing flux through the native photorespiratory pathway, installing non-native alternative photorespiratory pathways, and lowering or even eliminating Rubisco-catalyzed oxygenation of RuBP to reduce substrate entrance into the photorespiratory cycle. Some proposed designs have been successful at the proof of concept level. A plant systems-engineering approach, based on new opportunities available from synthetic biology to implement in silico designs, holds promise for further progress toward delivering more productive crops to farmer's fields.
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bile acid sodium symporter bass6 can transport glycolate and is involved in photorespiratory metabolism in arabidopsis thaliana
The Plant Cell, 2017Co-Authors: Amanda P Cavanagh, Vivien Rolland, Berkley J Walker, Paul F South, Murray R BadgerAbstract:Photorespiration is an energy-intensive process that recycles 2-phosphoglycolate, a toxic product of the Rubisco oxygenation reaction. The photorespiratory pathway is highly compartmentalized, involving the chloroplast, peroxisome, cytosol, and mitochondria. Though the soluble enzymes involved in Photorespiration are well characterized, very few membrane transporters involved in Photorespiration have been identified to date. In this work, Arabidopsis thaliana plants containing a T-DNA disruption of the bile acid sodium symporter BASS6 show decreased photosynthesis and slower growth under ambient, but not elevated CO2. Exogenous expression of BASS6 complemented this Photorespiration mutant phenotype. In addition, metabolite analysis and genetic complementation of glycolate transport in yeast showed that BASS6 was capable of glycolate transport. This is consistent with its involvement in the photorespiratory export of glycolate from Arabidopsis chloroplasts. An Arabidopsis double knockout line of both BASS6 and the glycolate/glycerate transporter PLGG1 (bass6, plgg1) showed an additive growth defect, an increase in glycolate accumulation, and reductions in photosynthetic rates compared with either single mutant. Our data indicate that BASS6 and PLGG1 partner in glycolate export from the chloroplast, whereas PLGG1 alone accounts for the import of glycerate. BASS6 and PLGG1 therefore balance the export of two glycolate molecules with the import of one glycerate molecule during Photorespiration.
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physiological evidence for plasticity in glycolate glycerate transport during Photorespiration
Photosynthesis Research, 2016Co-Authors: Berkley J Walker, Paul F SouthAbstract:Photorespiration recycles fixed carbon following the oxygenation reaction of Ribulose, 1–5, carboxylase oxygenase (Rubisco). The recycling of photorespiratory C2 to C3 intermediates is not perfectly efficient and reduces photosynthesis in C3 plants. Recently, a plastidic glycolate/glycerate transporter (PLGG1) in Photorespiration was identified in Arabidopsis thaliana, but it is not known how critical this transporter is for maintaining photorespiratory efficiency. We examined a mutant deficient in PLGG1 (plgg1-1) using modeling, gas exchange, and Rubisco biochemistry. Under low light (under 65 μmol m−2 s−1 PAR), there was no difference in the quantum efficiency of CO2 assimilation or in the photorespiratory CO2 compensation point of plgg1-1, indicating that Photorespiration proceeded with wild-type efficiency under sub-saturating light irradiances. Under saturating light irradiance (1200 μmol m−2 s−1 PAR), plgg1-1 showed decreased CO2 assimilation that was explained by decreases in the maximum rate of Rubisco carboxylation and photosynthetic linear electron transport. Decreased rates of Rubisco carboxylation resulted from probable decreases in the Rubisco activation state. These results suggest that glycolate/glycerate transport during Photorespiration can proceed in moderate rates through an alternative transport process with wild-type efficiencies. These findings also suggest that decreases in net CO2 assimilation that occur due to disruption to Photorespiration can occur by decreases in Rubisco activity and not necessarily decreases in the recycling efficiency of Photorespiration.
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Physiological evidence for plasticity in glycolate/glycerate transport during Photorespiration
Photosynthesis Research, 2016Co-Authors: Berkley J Walker, Paul F SouthAbstract:Photorespiration recycles fixed carbon following the oxygenation reaction of Ribulose, 1–5, carboxylase oxygenase (Rubisco). The recycling of photorespiratory C2 to C3 intermediates is not perfectly efficient and reduces photosynthesis in C3 plants. Recently, a plastidic glycolate/glycerate transporter (PLGG1) in Photorespiration was identified in Arabidopsis thaliana, but it is not known how critical this transporter is for maintaining photorespiratory efficiency. We examined a mutant deficient in PLGG1 (plgg1-1) using modeling, gas exchange, and Rubisco biochemistry. Under low light (under 65 μmol m−2 s−1 PAR), there was no difference in the quantum efficiency of CO2 assimilation or in the photorespiratory CO2 compensation point of plgg1-1, indicating that Photorespiration proceeded with wild-type efficiency under sub-saturating light irradiances. Under saturating light irradiance (1200 μmol m−2 s−1 PAR), plgg1-1 showed decreased CO2 assimilation that was explained by decreases in the maximum rate of Rubisco carboxylation and photosynthetic linear electron transport. Decreased rates of Rubisco carboxylation resulted from probable decreases in the Rubisco activation state. These results suggest that glycolate/glycerate transport during Photorespiration can proceed in moderate rates through an alternative transport process with wild-type efficiencies. These findings also suggest that decreases in net CO2 assimilation that occur due to disruption to Photorespiration can occur by decreases in Rubisco activity and not necessarily decreases in the recycling efficiency of Photorespiration.
Berkley J Walker - One of the best experts on this subject based on the ideXlab platform.
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bile acid sodium symporter bass6 can transport glycolate and is involved in photorespiratory metabolism in arabidopsis thaliana
The Plant Cell, 2017Co-Authors: Amanda P Cavanagh, Vivien Rolland, Berkley J Walker, Paul F South, Murray R BadgerAbstract:Photorespiration is an energy-intensive process that recycles 2-phosphoglycolate, a toxic product of the Rubisco oxygenation reaction. The photorespiratory pathway is highly compartmentalized, involving the chloroplast, peroxisome, cytosol, and mitochondria. Though the soluble enzymes involved in Photorespiration are well characterized, very few membrane transporters involved in Photorespiration have been identified to date. In this work, Arabidopsis thaliana plants containing a T-DNA disruption of the bile acid sodium symporter BASS6 show decreased photosynthesis and slower growth under ambient, but not elevated CO2. Exogenous expression of BASS6 complemented this Photorespiration mutant phenotype. In addition, metabolite analysis and genetic complementation of glycolate transport in yeast showed that BASS6 was capable of glycolate transport. This is consistent with its involvement in the photorespiratory export of glycolate from Arabidopsis chloroplasts. An Arabidopsis double knockout line of both BASS6 and the glycolate/glycerate transporter PLGG1 (bass6, plgg1) showed an additive growth defect, an increase in glycolate accumulation, and reductions in photosynthetic rates compared with either single mutant. Our data indicate that BASS6 and PLGG1 partner in glycolate export from the chloroplast, whereas PLGG1 alone accounts for the import of glycerate. BASS6 and PLGG1 therefore balance the export of two glycolate molecules with the import of one glycerate molecule during Photorespiration.
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physiological evidence for plasticity in glycolate glycerate transport during Photorespiration
Photosynthesis Research, 2016Co-Authors: Berkley J Walker, Paul F SouthAbstract:Photorespiration recycles fixed carbon following the oxygenation reaction of Ribulose, 1–5, carboxylase oxygenase (Rubisco). The recycling of photorespiratory C2 to C3 intermediates is not perfectly efficient and reduces photosynthesis in C3 plants. Recently, a plastidic glycolate/glycerate transporter (PLGG1) in Photorespiration was identified in Arabidopsis thaliana, but it is not known how critical this transporter is for maintaining photorespiratory efficiency. We examined a mutant deficient in PLGG1 (plgg1-1) using modeling, gas exchange, and Rubisco biochemistry. Under low light (under 65 μmol m−2 s−1 PAR), there was no difference in the quantum efficiency of CO2 assimilation or in the photorespiratory CO2 compensation point of plgg1-1, indicating that Photorespiration proceeded with wild-type efficiency under sub-saturating light irradiances. Under saturating light irradiance (1200 μmol m−2 s−1 PAR), plgg1-1 showed decreased CO2 assimilation that was explained by decreases in the maximum rate of Rubisco carboxylation and photosynthetic linear electron transport. Decreased rates of Rubisco carboxylation resulted from probable decreases in the Rubisco activation state. These results suggest that glycolate/glycerate transport during Photorespiration can proceed in moderate rates through an alternative transport process with wild-type efficiencies. These findings also suggest that decreases in net CO2 assimilation that occur due to disruption to Photorespiration can occur by decreases in Rubisco activity and not necessarily decreases in the recycling efficiency of Photorespiration.
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Physiological evidence for plasticity in glycolate/glycerate transport during Photorespiration
Photosynthesis Research, 2016Co-Authors: Berkley J Walker, Paul F SouthAbstract:Photorespiration recycles fixed carbon following the oxygenation reaction of Ribulose, 1–5, carboxylase oxygenase (Rubisco). The recycling of photorespiratory C2 to C3 intermediates is not perfectly efficient and reduces photosynthesis in C3 plants. Recently, a plastidic glycolate/glycerate transporter (PLGG1) in Photorespiration was identified in Arabidopsis thaliana, but it is not known how critical this transporter is for maintaining photorespiratory efficiency. We examined a mutant deficient in PLGG1 (plgg1-1) using modeling, gas exchange, and Rubisco biochemistry. Under low light (under 65 μmol m−2 s−1 PAR), there was no difference in the quantum efficiency of CO2 assimilation or in the photorespiratory CO2 compensation point of plgg1-1, indicating that Photorespiration proceeded with wild-type efficiency under sub-saturating light irradiances. Under saturating light irradiance (1200 μmol m−2 s−1 PAR), plgg1-1 showed decreased CO2 assimilation that was explained by decreases in the maximum rate of Rubisco carboxylation and photosynthetic linear electron transport. Decreased rates of Rubisco carboxylation resulted from probable decreases in the Rubisco activation state. These results suggest that glycolate/glycerate transport during Photorespiration can proceed in moderate rates through an alternative transport process with wild-type efficiencies. These findings also suggest that decreases in net CO2 assimilation that occur due to disruption to Photorespiration can occur by decreases in Rubisco activity and not necessarily decreases in the recycling efficiency of Photorespiration.
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the costs of Photorespiration to food production now and in the future
Annual Review of Plant Biology, 2016Co-Authors: Berkley J Walker, Andy Vanloocke, Carl J BernacchiAbstract:Photorespiration is essential for C3 plants but operates at the massive expense of fixed carbon dioxide and energy. Photorespiration is initiated when the initial enzyme of photosynthesis, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), reacts with oxygen instead of carbon dioxide and produces a toxic compound that is then recycled by Photorespiration. Photorespiration can be modeled at the canopy and regional scales to determine its cost under current and future atmospheres. A regional-scale model reveals that Photorespiration currently decreases US soybean and wheat yields by 36% and 20%, respectively, and a 5% decrease in the losses due to Photorespiration would be worth approximately $500 million annually in the United States. Furthermore, Photorespiration will continue to impact yield under future climates despite increases in carbon dioxide, with models suggesting a 12–55% improvement in gross photosynthesis in the absence of Photorespiration, even under climate change scenarios predictin...
Eduardo Blumwald - One of the best experts on this subject based on the ideXlab platform.
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silencing of oscv chloroplast vesiculation maintained Photorespiration and n assimilation in rice plants grown under elevated co2
Plant Cell and Environment, 2020Co-Authors: Kamolchanok Umnajkitikorn, Nir Sade, Maria Del Mar Rubio Wilhelmi, Matthew E Gilbert, Eduardo BlumwaldAbstract:High CO2 concentrations stimulate net photosynthesis by increasing CO2 substrate availability for Rubisco, simultaneously suppressing Photorespiration. Previously, we reported that silencing the chloroplast vesiculation (cv) gene in rice increased source fitness, through the maintenance of chloroplast stability and the expression of Photorespiration-associated genes. Because high atmospheric CO2 conditions diminished Photorespiration, we tested whether CV silencing might be a viable strategy to improve the effects of high CO2 on grain yield and N assimilation in rice. Under elevated CO2 , OsCV expression was induced, and OsCV was targeted to peroxisomes where it facilitated the removal of OsPEX11-1 from the peroxisome and delivered it to the vacuole for degradation. This process correlated well with the reduction in the number of peroxisomes, the decreased catalase activity and the increased H2 O2 content in wild-type plants under elevated CO2 . At elevated CO2 , CV-silenced rice plants maintained peroxisome proliferation and Photorespiration and displayed higher N assimilation than wild-type plants. This was supported by higher activity of enzymes involved in NO3- and NH4+ assimilation and higher total and seed protein contents. Co-immunoprecipitation of OsCV-interacting proteins suggested that, similar to its role in chloroplast protein turnover, OsCV acted as a scaffold, binding peroxisomal proteins.
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cytokinin dependent Photorespiration and the protection of photosynthesis during water deficit
Plant Physiology, 2009Co-Authors: Rosa M Rivero, Vladimir Shulaev, Eduardo BlumwaldAbstract:We investigated the effects of PSARK∷IPT (for Senescence-Associated Receptor Kinase∷Isopentenyltransferase) expression and cytokinin production on several aspects of photosynthesis in transgenic tobacco (Nicotiana tabacum cv SR1) plants grown under optimal or restricted (30% of optimal) watering regimes. There were no significant differences in stomatal conductance between leaves from wild-type and transgenic PSARK-IPT plants grown under optimal or restricted watering. On the other hand, there was a significant reduction in the maximum rate of electron transport as well as the use of triose-phosphates only in wild-type plants during growth under restricted watering, indicating a biochemical control of photosynthesis during growth under water deficit. During water deficit conditions, the transgenic plants displayed an increase in catalase inside peroxisomes, maintained a physical association among chloroplasts, peroxisomes, and mitochondria, and increased the CO2 compensation point, indicating the cytokinin-mediated occurrence of Photorespiration in the transgenic plants. The contribution of Photorespiration to the tolerance of transgenic plants to water deficit was also supported by the increase in transcripts coding for enzymes involved in the conversion of glycolate to ribulose-1,5-bisphosphate. Moreover, the increase in transcripts indicated a cytokinin-induced elevation in Photorespiration, suggesting the contribution of Photorespiration in the protection of photosynthetic processes and its beneficial role during water stress.
Hermann Bauwe - One of the best experts on this subject based on the ideXlab platform.
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Photorespiration and the potential to improve photosynthesis
Current Opinion in Chemical Biology, 2016Co-Authors: Martin Hagemann, Hermann BauweAbstract:The photorespiratory pathway, in short Photorespiration, is an essential metabolite repair pathway that allows the photosynthetic CO 2 fixation of plants to occur in the presence of oxygen. It is necessary because oxygen is a competing substrate of the CO 2 -fixing enzyme ribulose 1,5-bisphosphate carboxylase, forming 2-phosphoglycolate that negatively interferes with photosynthesis. Photorespiration very efficiently recycles 2-phosphoglycolate into 3-phosphoglycerate, which re-enters the Calvin–Benson cycle to drive sustainable photosynthesis. Photorespiration however requires extra energy and re-oxidises one quarter of the 2-phosphoglycolate carbon to CO 2 , lowering potential maximum rates of photosynthesis in most plants including food and energy crops. This review discusses natural and artificial strategies to reduce the undesired impact of air oxygen on photosynthesis and in turn plant growth.
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can cyanobacteria serve as a model of plant Photorespiration a comparative meta analysis of metabolite profiles
Journal of Experimental Botany, 2016Co-Authors: Stefan Timm, Hermann Bauwe, Alisdair R Fernie, Martin Hagemann, Joachim Kopka, Zoran NikoloskiAbstract:: Photorespiration is a process that is crucial for the survival of oxygenic phototrophs in environments that favour the oxygenation reaction of Rubisco. While Photorespiration is conserved among cyanobacteria, algae, and embryophytes, it evolved to different levels of complexity in these phyla. The highest complexity is found in embryophytes, where the pathway involves four cellular compartments and respective transport processes. The complexity of Photorespiration in embryophytes raises the question whether a simpler system, such as cyanobacteria, may serve as a model to facilitate our understanding of the common key aspects of Photorespiration. In this study, we conducted a meta-analysis of publicly available metabolite profiles from the embryophyte Arabidopsis thaliana and the cyanobacterium Synechocystis sp. PCC 6803 grown under conditions that either activate or suppress Photorespiration. The comparative meta-analysis evaluated the similarity of metabolite profiles, the variability of metabolite pools, and the patterns of metabolite ratios. Our results show that the metabolic signature of Photorespiration is in part conserved between the compared model organisms under conditions that favour the oxygenation reaction. Therefore, our findings support the claim that cyanobacteria can serve as prokaryotic models of Photorespiration in embryophytes.
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evolution of Photorespiration from cyanobacteria to land plants considering protein phylogenies and acquisition of carbon concentrating mechanisms
Journal of Experimental Botany, 2016Co-Authors: Martin Hagemann, Andreas P M Weber, Ramona Kern, Veronica G Maurino, David T Hanson, Rowan F Sage, Hermann BauweAbstract:: Photorespiration and oxygenic photosynthesis are intimately linked processes. It has been shown that under the present day atmospheric conditions cyanobacteria and all eukaryotic phototrophs need functional Photorespiration to grow autotrophically. The question arises as to when this essential partnership evolved, i.e. can we assume a coevolution of both processes from the beginning or did Photorespiration evolve later to compensate for the generation of 2-phosphoglycolate (2PG) due to Rubisco's oxygenase reaction? This question is mainly discussed here using phylogenetic analysis of proteins involved in the 2PG metabolism and the acquisition of different carbon concentrating mechanisms (CCMs). The phylogenies revealed that the enzymes involved in the Photorespiration of vascular plants have diverse origins, with some proteins acquired from cyanobacteria as ancestors of the chloroplasts and others from heterotrophic bacteria as ancestors of mitochondria in the plant cell. Only phosphoglycolate phosphatase was found to originate from Archaea. Notably glaucophyte algae, the earliest branching lineage of Archaeplastida, contain more photorespiratory enzymes of cyanobacterial origin than other algal lineages or land plants indicating a larger initial contribution of cyanobacterial-derived proteins to eukaryotic Photorespiration. The acquisition of CCMs is discussed as a proxy for assessing the timing of periods when photorespiratory activity may have been enhanced. The existence of CCMs also had marked influence on the structure and function of Photorespiration. Here, we discuss evidence for an early and continuous coevolution of Photorespiration, CCMs and photosynthesis starting from cyanobacteria via algae, to land plants.
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serine acts as metabolic signal for the transcriptional control of Photorespiration related genes in arabidopsis thaliana
Plant Physiology, 2013Co-Authors: Stefan Timm, Alisdair R Fernie, Martin Hagemann, Alexandra Florian, Maria Wittmis, Kathrin Jahnke, Hermann BauweAbstract:Photosynthetic carbon assimilation including Photorespiration is dynamically regulated during the day/night cycle. This includes transcriptional regulation, such as the light induction of corresponding genes, but little is known about the contribution of photorespiratory metabolites to the regulation of gene expression. Here, we examined diurnal changes in the levels of photorespiratory metabolites, of enzymes of the photorespiratory carbon cycle, and of corresponding transcripts in wild-type plants of Arabidopsis (Arabidopsis thaliana) and in a mutant with altered photorespiratory flux due to the absence of the peroxisomal enzyme Hydroxypyruvate Reductase1 (HPR1). Metabolomics of the wild type showed that the relative amounts of most metabolites involved in Photorespiration increased after the onset of light, exhibited maxima at the end of the day, and decreased during the night. In accordance with those findings, both the amounts of messenger RNAs encoding photorespiratory enzymes and the respective protein contents showed a comparable accumulation pattern. Deletion of HPR1 did not significantly alter most of the metabolite patterns relative to wild-type plants; only serine accumulated to a constitutively elevated amount in this mutant. In contrast, the hpr1 mutation resulted in considerable deregulation of the transcription of Photorespiration-related genes. This transcriptional deregulation could also be induced by the external application of l-serine but not glycine to the Arabidopsis wild type, suggesting that serine acts as a metabolic signal for the transcriptional regulation of Photorespiration, particularly in the glycine-to-serine interconversion reactions.
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Photorespiration players partners and origin
Trends in Plant Science, 2010Co-Authors: Hermann Bauwe, Martin Hagemann, Alisdair R FernieAbstract:Photorespiratory metabolism allows plants to thrive in a high-oxygen containing environment. This metabolic pathway recycles phosphoglycolate, a toxic compound, back to phosphoglycerate, when oxygen substitutes for carbon dioxide in the first reaction of photosynthetic carbon fixation. The recovery of phosphoglycerate is accompanied by considerable carbon and energy losses, making Photorespiration a prime target for crop improvement. The genomics era has allowed the precise functional analysis of individual reaction steps of the photorespiratory cycle, and more links integrating Photorespiration with cellular metabolism as a whole are becoming apparent. Here we review the evolutionary origins of Photorespiration as well as new insights into the interaction with other metabolic processes such as nitrogen assimilation and mitochondrial respiration.
Andreas P M Weber - One of the best experts on this subject based on the ideXlab platform.
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mechanistic understanding of Photorespiration paves the way to a new green revolution
New Phytologist, 2019Co-Authors: Marion Eisenhut, Marcsven Roell, Andreas P M WeberAbstract:: Photorespiration is frequently considered a wasteful and inefficient process. However, mutant analysis demonstrated that Photorespiration is essential for recycling of 2-phosphoglycolate in C3 and C4 land plants, in algae, and even in cyanobacteria operating carboxysome-based carbon (C) concentrating mechanisms. Photorespiration links photosynthetic C assimilation with other metabolic processes, such as nitrogen and sulfur assimilation, as well as C1 metabolism, and it may contribute to balancing the redox poise between chloroplasts, peroxisomes, mitochondria and cytoplasm. The high degree of metabolic interdependencies and the pleiotropic phenotypes of photorespiratory mutants impedes the distinction between core and accessory functions. Newly developed synthetic bypasses of Photorespiration, beyond holding potential for significant yield increases in C3 crops, will enable us to differentiate between essential and accessory functions of Photorespiration.
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Photorespiration: origins and metabolic integration in interacting compartments
Journal of Experimental Botany, 2016Co-Authors: Martin Hagemann, Andreas P M Weber, Marion EisenhutAbstract:This special issue on Photorespiration focuses on recent advances in this topic. The majority of the papers summarizes and extends contributions given at the 2nd workshop, ‘Photorespiration–key to better crops’, held in Warnemuende, Germany in June 2015. This was organized by the DFG (German Research Foundation)-supported research network, ‘Photorespiration: origins and metabolic integration in interacting compartments’ (FOR 1186–Promics).
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evolution of Photorespiration from cyanobacteria to land plants considering protein phylogenies and acquisition of carbon concentrating mechanisms
Journal of Experimental Botany, 2016Co-Authors: Martin Hagemann, Andreas P M Weber, Ramona Kern, Veronica G Maurino, David T Hanson, Rowan F Sage, Hermann BauweAbstract:: Photorespiration and oxygenic photosynthesis are intimately linked processes. It has been shown that under the present day atmospheric conditions cyanobacteria and all eukaryotic phototrophs need functional Photorespiration to grow autotrophically. The question arises as to when this essential partnership evolved, i.e. can we assume a coevolution of both processes from the beginning or did Photorespiration evolve later to compensate for the generation of 2-phosphoglycolate (2PG) due to Rubisco's oxygenase reaction? This question is mainly discussed here using phylogenetic analysis of proteins involved in the 2PG metabolism and the acquisition of different carbon concentrating mechanisms (CCMs). The phylogenies revealed that the enzymes involved in the Photorespiration of vascular plants have diverse origins, with some proteins acquired from cyanobacteria as ancestors of the chloroplasts and others from heterotrophic bacteria as ancestors of mitochondria in the plant cell. Only phosphoglycolate phosphatase was found to originate from Archaea. Notably glaucophyte algae, the earliest branching lineage of Archaeplastida, contain more photorespiratory enzymes of cyanobacterial origin than other algal lineages or land plants indicating a larger initial contribution of cyanobacterial-derived proteins to eukaryotic Photorespiration. The acquisition of CCMs is discussed as a proxy for assessing the timing of periods when photorespiratory activity may have been enhanced. The existence of CCMs also had marked influence on the structure and function of Photorespiration. Here, we discuss evidence for an early and continuous coevolution of Photorespiration, CCMs and photosynthesis starting from cyanobacteria via algae, to land plants.
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perspectives for a better understanding of the metabolic integration of Photorespiration within a complex plant primary metabolism network
Journal of Experimental Botany, 2016Co-Authors: Michael Hodges, Rowan F Sage, A S Raghavendra, Younes Dellero, Olivier Keech, Marco Betti, Doug K Allen, Andreas P M WeberAbstract:: Photorespiration is an essential high flux metabolic pathway that is found in all oxygen-producing photosynthetic organisms. It is often viewed as a closed metabolic repair pathway that serves to detoxify 2-phosphoglycolic acid and to recycle carbon to fuel the Calvin-Benson cycle. However, this view is too simplistic since the photorespiratory cycle is known to interact with several primary metabolic pathways, including photosynthesis, nitrate assimilation, amino acid metabolism, C1 metabolism and the Krebs (TCA) cycle. Here we will review recent advances in Photorespiration research and discuss future priorities to better understand (i) the metabolic integration of the photorespiratory cycle within the complex network of plant primary metabolism and (ii) the importance of Photorespiration in response to abiotic and biotic stresses.
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plant peroxisomes respire in the light some gaps of the photorespiratory c2 cycle have become filled others remain
Biochimica et Biophysica Acta, 2006Co-Authors: Sigrun Reumann, Andreas P M WeberAbstract:The most prominent role of peroxisomes in photosynthetic plant tissues is their participation in Photorespiration, a process also known as the oxidative C2 cycle or the oxidative photosynthetic carbon cycle. Photorespiration is an essential process in land plants, as evident from the conditionally lethal phenotype of mutants deficient in enzymes or transport proteins involved in this pathway. The oxidative C2 cycle is a salvage pathway for phosphoglycolate, the product of the oxygenase activity of ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), to the Calvin cycle intermediate phosphoglycerate. The pathway is highly compartmentalized and involves reactions in chloroplasts, peroxisomes, and mitochondria. The H2O2-producing enzyme glycolate oxidase, catalase, and several aminotransferases of the photorespiratory cycle are located in peroxisomes, with catalase representing the major constituent of the peroxisomal matrix in photosynthetic tissues. Although Photorespiration is of major importance for photosynthesis, the identification of the enzymes involved in this process has only recently been completed. Only little is known about the metabolite transporters for the exchange of photorespiratory intermediates between peroxisomes and the other organelles involved, and about the regulation of the photorespiratory pathway. This review highlights recent developments in understanding Photorespiration and identifies remaining gaps in our knowledge of this important metabolic pathway.
