title: C4photosynthesis in C3rice: a theoretical analysis of biochemical and anatomical factors.
abstract: Engineering C4photosynthesis into rice has been considered a promising strategy to increase photosynthesis and yield. A question that remains to be answered is whether expressing a C4metabolic cycle into a C3leaf structure and without removing the C3background metabolism improves photosynthetic efficiency. To explore this question, we developed a 3D reaction diffusion model of bundle-sheath and connected mesophyll cells in a C3rice leaf. Our results show that integrating a C4metabolic pathway into rice leaves with a C3metabolism and mesophyll structure may lead to an improved photosynthesis under current ambient CO2concentration. We analysed a number of physiological factors that influence the CO2uptake rate, which include the chloroplast surface area exposed to intercellular air space, bundle-sheath cell wall thickness, bundle-sheath chloroplast envelope permeability, Rubisco concentration and the energy partitioning between C3and C4cycles. Among these, partitioning of energy between C3and C4photosynthesis and the partitioning of Rubisco between mesophyll and bundle-sheath cells are decisive factors controlling photosynthetic efficiency in an engineered C3-C4leaf. The implications of the results for the sequence of C4evolution are also discussed.
authors.affiliation: Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Shuyue
authors.initials: S
authors.lastname: Wang
authors.affiliation: Institute of Botany, Department of Integrative Biology, University of Natural Resources and Applied Life Sciences, BOKU Vienna, Gregor-Mendel-Str. 33, A-1180, Vienna, Austria.
authors.forename: Danny
authors.initials: D
authors.lastname: Tholen
authors.affiliation: Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Xin-Guang
authors.initials: XG
authors.lastname: Zhu
mesh_terms: D001669:Biochemical Phenomena; D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism; D004058:Diffusion; D058503:Mesophyll Cells / Q000378:metabolism; D008954:Models, Biological; D012275:Oryza / Q000033:anatomy & histology* / Q000502:physiology*; D010788:Photosynthesis
chemical_list: D002245:Carbon Dioxide; D002244:Carbon
keywords: 3D anatomy; reaction diffusion process; systems modeling