title: The benefits of photorespiratory bypasses: how can they work?
abstract: Bypassing the photorespiratory pathway is regarded as a way to increase carbon assimilation and, correspondingly, biomass production in C3 crops. Here, the benefits of three published photorespiratory bypass strategies are systemically explored using a systems-modeling approach. Our analysis shows that full decarboxylation of glycolate during photorespiration would decrease photosynthesis, because a large amount of the released CO2 escapes back to the atmosphere. Furthermore, we show that photosynthesis can be enhanced by lowering the energy demands of photorespiration and by relocating photorespiratory CO2 release into the chloroplasts. The conductance of the chloroplast membranes to CO2 is a key feature determining the benefit of the relocation of photorespiratory CO2 release. Although our results indicate that the benefit of photorespiratory bypasses can be improved by increasing sedoheptulose bisphosphatase activity and/or increasing the flux through the bypass, the effectiveness of such approaches depends on the complex regulation between photorespiration and other metabolic pathways.
authors.affiliation: Key Laboratory of Computational Biology, Chinese Academy of Sciences-German Max Planck Society Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China (C.-P.X., D.T., V.D., X.-G.Z.);Shanghai Botanical Garden, Shanghai 200231, China (C.-P.X.);Institute of Botany, Department of Integrative Biology, Universität für Bodenkultur Wien, Vienna, A-1180 Vienna, Austria (D.T.); andState Key Laboratory of Hybrid Rice Research, Changsha, Hunan Province 410125, China (X.-G.Z.).
authors.forename: Chang-Peng
authors.initials: CP
authors.lastname: Xin
authors.affiliation: Key Laboratory of Computational Biology, Chinese Academy of Sciences-German Max Planck Society Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China (C.-P.X., D.T., V.D., X.-G.Z.);Shanghai Botanical Garden, Shanghai 200231, China (C.-P.X.);Institute of Botany, Department of Integrative Biology, Universität für Bodenkultur Wien, Vienna, A-1180 Vienna, Austria (D.T.); andState Key Laboratory of Hybrid Rice Research, Changsha, Hunan Province 410125, China (X.-G.Z.).
authors.forename: Danny
authors.initials: D
authors.lastname: Tholen
authors.affiliation: Key Laboratory of Computational Biology, Chinese Academy of Sciences-German Max Planck Society Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China (C.-P.X., D.T., V.D., X.-G.Z.);Shanghai Botanical Garden, Shanghai 200231, China (C.-P.X.);Institute of Botany, Department of Integrative Biology, Universität für Bodenkultur Wien, Vienna, A-1180 Vienna, Austria (D.T.); andState Key Laboratory of Hybrid Rice Research, Changsha, Hunan Province 410125, China (X.-G.Z.).
authors.forename: Vincent
authors.initials: V
authors.lastname: Devloo
authors.affiliation: Key Laboratory of Computational Biology, Chinese Academy of Sciences-German Max Planck Society Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China (C.-P.X., D.T., V.D., X.-G.Z.);Shanghai Botanical Garden, Shanghai 200231, China (C.-P.X.);Institute of Botany, Department of Integrative Biology, Universität für Bodenkultur Wien, Vienna, A-1180 Vienna, Austria (D.T.); andState Key Laboratory of Hybrid Rice Research, Changsha, Hunan Province 410125, China (X.-G.Z.) zhuxinguang@picb.ac.cn.
authors.forename: Xin-Guang
authors.initials: XG
authors.lastname: Zhu
mesh_terms: D002245:Carbon Dioxide / Q000494:pharmacology; D019069:Cell Respiration / Q000187:drug effects / Q000528:radiation effects; D003198:Computer Simulation; D004734:Energy Metabolism / Q000187:drug effects / Q000528:radiation effects; D007700:Kinetics; D008027:Light; D008954:Models, Biological; D010788:Photosynthesis / Q000187:drug effects / Q000528:radiation effects*
chemical_list: D002245:Carbon Dioxide