title: A profiling approach of the natural variability of foliar N remobilization at the rosette stage gives clues to understand the limiting processes involved in the low N use efficiency of winter oilseed rape.
abstract: Oilseed rape, a crop requiring a high level of nitogen (N) fertilizers, is characterized by low N use efficiency. To identify the limiting factors involved in the N use efficiency of winter oilseed rape, the response to low N supply was investigated at the vegetative stage in 10 genotypes by using long-term pulse-chase (15)N labelling and studying the physiological processes of leaf N remobilization. Analysis of growth and components of N use efficiency allowed four profiles to be defined. Group 1 was characterized by an efficient N remobilization under low and high N conditions but by a decrease of leaf growth under N limitation. Group 2 showed a decrease in leaf growth under low N supply that was associated with a low N remobilization efficiency under both N supplies despite a high remobilization of soluble proteins. In response to N limitation, Group 3 is characterized by an increase in N use efficiency and leaf N remobilization compared with high N that is not sufficient to sustain the leaf biomass production at a similar level to non-limited plants. Genotypes of Group 4 subjected to low nitrate were able to maintain leaf growth to the same level as under high N. The profiling approach indicated that enhancement of amino acid export and soluble protein degradation was crucial for N remobilization improvement. At the whole-plant level, N fluxes revealed that Group 4 showed a high N remobilization in source leaves combined with a better N utilization in young leaves. Consequently, an enhanced N remobilization limits N loss in fallen leaves, but this remobilized N needs to be efficiently utilized in young leaves to improve N use efficiency.
authors: Université de Caen Basse-Normandie, F-14032 Caen, France UCBN, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., F-14032 Caen, France INRA, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., F-14032 Caen, France.
authors: Alexandra
authors: A
authors: Girondé
authors: Université de Caen Basse-Normandie, F-14032 Caen, France UCBN, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., F-14032 Caen, France INRA, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., F-14032 Caen, France.
authors: Marine
authors: M
authors: Poret
authors: Université de Caen Basse-Normandie, F-14032 Caen, France UCBN, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., F-14032 Caen, France INRA, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., F-14032 Caen, France.
authors: Philippe
authors: P
authors: Etienne
authors: Université de Caen Basse-Normandie, F-14032 Caen, France UCBN, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., F-14032 Caen, France INRA, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., F-14032 Caen, France.
authors: Jacques
authors: J
authors: Trouverie
authors: INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, INRA, Agrocampus Ouest, Université de Rennes 1, F-35653 Le Rheu, France.
authors: Alain
authors: A
authors: Bouchereau
authors: INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, INRA, Agrocampus Ouest, Université de Rennes 1, F-35653 Le Rheu, France.
authors: Françoise
authors: F
authors: Le Cahérec
authors: INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, INRA, Agrocampus Ouest, Université de Rennes 1, F-35653 Le Rheu, France.
authors: Laurent
authors: L
authors: Leport
authors: INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, INRA, Agrocampus Ouest, Université de Rennes 1, F-35653 Le Rheu, France Université d'Angers, UMR 1345 Institut de Recherche en Horticulture et Semences, SFR 4207 QUASAV, PRES L'UNAM, F-49045 Angers, France AgroCampus-Ouest, UMR 1345 Institut de Recherche en Horticulture et Semences, F-49045 Angers, France.
authors: Mathilde
authors: M
authors: Orsel
authors: INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, INRA, Agrocampus Ouest, Université de Rennes 1, F-35653 Le Rheu, France.
authors: Marie-Françoise
authors: MF
authors: Niogret
authors: INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, INRA, Agrocampus Ouest, Université de Rennes 1, F-35653 Le Rheu, France.
authors: Carole
authors: C
authors: Deleu
authors: Université de Caen Basse-Normandie, F-14032 Caen, France UCBN, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., F-14032 Caen, France INRA, UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., F-14032 Caen, France jean-christophe.avice@unicaen.fr.
authors: Jean-Christophe
authors: JC
authors: Avice
mesh_terms: D029688:Brassica napus / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D014644:Genetic Variation; D005838:Genotype; D009584:Nitrogen / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D009584:Nitrogen
keywords: Brassica napus; amino acids; genotypic variability; nitrogen remobilization efficiency; nitrogen use efficiency; nitrogen utilization efficiency; soluble proteins.