title: Analysis and modeling of the integrative response of Medicago truncatula to nitrogen constraints.
abstract: An integrative biology approach was conducted in Medicago truncatula for: (i) unraveling the coordinated regulation of NO3-, NH4+ and N(2) acquisition by legumes to fulfill the plant N demand; and (ii) modeling the emerging properties occurring at the whole plant level. Upon localized addition of a high level of mineral N, the three N acquisition pathways displayed similar systemic feedback repression to adjust N acquisition capacities to the plant N status. Genes associated to these responses were in contrast rather specific to the N source. Following an N deficit, NO3- fed plants maintained efficiently their N status through rapid functional and developmental up regulations while N(2) fed plants responded by long term plasticity of nodule development. Regulatory genes associated with various symbiotic stages were further identified. An ecophysiological model simulating relations between leaf area and roots N retrieval was developed and now furnishes an analysis grid to characterize a spontaneous or induced genetic variability for plant N nutrition.
authors.affiliation: INRA ENESAD, UMR 102 génétique et ecophysiologie des légumineuses (UMR LEG), 17, rue Sully, BP 86510, 21065 Dijon cedex, France. salon@dijon.inra.fr
authors.forename: Christophe
authors.initials: C
authors.lastname: Salon
authors.forename: Marc
authors.initials: M
authors.lastname: Lepetit
authors.forename: Pascal
authors.initials: P
authors.lastname: Gamas
authors.forename: Christian
authors.initials: C
authors.lastname: Jeudy
authors.forename: Sandra
authors.initials: S
authors.lastname: Moreau
authors.forename: Delphine
authors.initials: D
authors.lastname: Moreau
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Voisin
authors.forename: Gérard
authors.initials: G
authors.lastname: Duc
authors.forename: Virginie
authors.initials: V
authors.lastname: Bourion
authors.forename: Nathalie
authors.initials: N
authors.lastname: Munier-Jolain
mesh_terms: D000222:Adaptation, Physiological; D025461:Feedback, Physiological; D005308:Fertilizers; D017343:Genes, Plant; D005809:Genes, Regulator; D046913:Medicago truncatula / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D008954:Models, Biological; D009566:Nitrates / Q000378:metabolism / Q000494:pharmacology*; D009584:Nitrogen / Q000378:metabolism*; D009586:Nitrogen Fixation / Q000235:genetics / Q000502:physiology*; D018515:Plant Leaves / Q000378:metabolism; D055170:Plant Root Nodulation / Q000235:genetics / Q000502:physiology; D018517:Plant Roots / Q000378:metabolism / Q000382:microbiology; D018520:Plant Shoots / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism / Q000494:pharmacology*; D053204:Root Nodules, Plant / Q000254:growth & development / Q000382:microbiology; D016962:Sinorhizobium meliloti / Q000502:physiology; D013559:Symbiosis; D018511:Systems Integration
chemical_list: D005308:Fertilizers; D009566:Nitrates; D000644:Quaternary Ammonium Compounds; D009584:Nitrogen