RT Journal Article SR Electronic T1 The intertwined metabolism of Medicago truncatula and its nitrogen fixing symbiont Sinorhizobium meliloti elucidated by genome-scale metabolic models JF bioRxiv FD Cold Spring Harbor Laboratory SP 067348 DO 10.1101/067348 A1 Thomas Pfau A1 Nils Christian A1 Shyam K. Masakapalli A1 Lee J. Sweetlove A1 Mark G. Poolman A1 Oliver Ebenhöh YR 2016 UL http://biorxiv.org/content/early/2016/08/02/067348.abstract AB Genome-scale metabolic network models can be used for various analyses including the prediction of metabolic responses to changes in the environment. Legumes are well known for their rhizobial symbiosis that introduces nitrogen into the global nutrient cycle. Here, we describe a fully compartmentalised, mass and charge-balanced, genome-scale model of the clover Medicago truncatula, which has been adopted as a model organism for legumes. We employed flux balance analysis to demonstrate that the network is capable of producing biomass (amino acids, nucleotides, lipids, cell wall) in experimentally observed proportions, during day and night. By connecting the plant model to a model of its rhizobial symbiont, Sinorhizobium meliloti, we were able to investigate the effects of the symbiosis on metabolic fluxes and plant growth and could demonstrate how oxygen availability influences metabolic exchanges between plant and symbiont, thus elucidating potential benefits of amino acid cycling. We thus provide a modelling framework, in which the interlinked metabolism of plants and nodules can be studied from a theoretical perspective.