Journal ArticleMetabolite shift in <i>Medicago truncatula</i> occurs in phosphorus deprivationDokwal, Dhiraj; Cocuron, Jean-Christophe; Alonso, Ana Paula; Dickstein, RebeccaNakamura, YukiAbstract Symbiotic nitrogen (N) fixation entails successful interaction between legume hosts and rhizobia that occur in specialized organs called nodules. N-fixing legumes have a higher demand for phosphorus (P) than legumes grown on mineral N. Medicago truncatula is an important model plant for characterization of effects of P deficiency at the molecular level. Hence, a study was carried out to address the alteration in metabolite levels of M. truncatula grown aeroponically and subjected to 4 weeks of P stress. First, GC-MS-based untargeted metabolomics initially revealed changes in the metabolic profile of nodules, with increased levels of amino acids and sugars and a decline in amounts of organic acids. Subsequently, LC-MS/MS was used to quantify these compounds including phosphorylated metabolites in the whole plant. Our results showed a drastic reduction in levels of organic acids and phosphorylated compounds in –P leaves, with a moderate reduction in –P roots and nodules. Additionally, sugars and amino acids were elevated in the whole plant under P deprivation. These findings provide evidence that N fixation in M. truncatula is mediated through a N feedback mechanism that in parallel is related to carbon and P metabolism.2021-12-3110346615Journal of Experimental Botany7372093 to 21110022-0957https://doi.org/10.1093/jxb/erab5592139351National Science Foundation