Multiscale Modeling of Metabolism and Its Regulation in C4 Plants

While much of the basic biochemistry associated with C4 photosynthesis is well understood, its regulation in developing plants and its role in the broader context of plant metabolism is less well characterized. To address such issues, we have constructed a multiscale mathematical model of metabolism in maize, an important C4 crop, that we have used to probe the regulation of metabolism in a developing leaf using high-resolution transcriptomic inputs. This work builds on our new genome-scale metabolic reconstruction for maize, our development of a novel computational method for integrating nonlinear kinetic constraints into constraint-based metabolic models, and the integration of a variety of transcriptomic data sets to parameterize enzymatic regulation as it unfolds during development. This analysis reproduces some of the observed physiology of developing leaves such as source-sink partitioning, and describes the reprogramming of maize metabolism from tissue dedicated to leaf development to that supporting carbon fixation through C4 photosynthesis.