title: Elements required for an efficient NADP-malic enzyme type C4 photosynthesis.
abstract: C4 photosynthesis has higher light, nitrogen, and water use efficiencies than C3 photosynthesis. Although the basic anatomical, cellular, and biochemical features of C4 photosynthesis are well understood, the quantitative significance of each element of C4 photosynthesis to the high photosynthetic efficiency are not well defined. Here, we addressed this question by developing and using a systems model of C4 photosynthesis, which includes not only the Calvin-Benson cycle, starch synthesis, sucrose synthesis, C4 shuttle, and CO₂ leakage, but also photorespiration and metabolite transport between the bundle sheath cells and mesophyll cells. The model effectively simulated the CO₂ uptake rates, and the changes of metabolite concentrations under varied CO₂ and light levels. Analyses show that triose phosphate transport and CO₂ leakage can help maintain a high photosynthetic rate by balancing ATP and NADPH amounts in bundle sheath cells and mesophyll cells. Finally, we used the model to define the optimal enzyme properties and a blueprint for C4 engineering. As such, this model provides a theoretical framework for guiding C4 engineering and studying C4 photosynthesis in general.
authors: State Key Laboratory for Hybrid Rice and Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors: Yu
authors: Y
authors: Wang
authors: Stephen P
authors: SP
authors: Long
authors: Xin-Guang
authors: XG
authors: Zhu
mesh_terms: D001692:Biological Transport / Q000528:radiation effects; D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D002247:Carbon Isotopes; D008027:Light; D008291:Malate Dehydrogenase / Q000378:metabolism*; D008954:Models, Biological; D009584:Nitrogen / Q000378:metabolism; D010788:Photosynthesis / Q000528:radiation effects; D031425:Plasmodesmata / Q000378:metabolism / Q000528:radiation effects; D015203:Reproducibility of Results
chemical_list: D002247:Carbon Isotopes; D002245:Carbon Dioxide; D002244:Carbon; D008291:Malate Dehydrogenase; C031917:malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+); D009584:Nitrogen