title: A Comparative Study of Proteolytic Mechanisms during Leaf Senescence of Four Genotypes of Winter Oilseed Rape Highlighted Relevant Physiological and Molecular Traits for NRE Improvement.
abstract: Winter oilseed rape is characterized by a low N use efficiency related to a weak leaf N remobilization efficiency (NRE) at vegetative stages. By investigating the natural genotypic variability of leaf NRE, our goal was to characterize the relevant physiological traits and the main protease classes associated with an efficient proteolysis and high leaf NRE in response to ample or restricted nitrate supply. The degradation rate of soluble proteins and D1 protein (a thylakoid-bound protein) were correlated to N remobilization, except for the genotype Samouraï which showed a low NRE despite high levels of proteolysis. Under restricted nitrate conditions, high levels of soluble protein degradation were associated with serine, cysteine and aspartic proteases at acidic pH. Low leaf NRE was related to a weak proteolysis of both soluble and thylakoid-bound proteins. The results obtained on the genotype Samouraï suggest that the timing between the onset of proteolysis and abscission could be a determinant. The specific involvement of acidic proteases suggests that autophagy and/or senescence-associated vacuoles are implicated in N remobilization under low N conditions. The data revealed that the rate of D1 degradation could be a relevant indicator of leaf NRE and might be used as a tool for plant breeding.
authors.affiliation: UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie &amp; Nutritions N.C.S., Université de Caen Normandie, F-14032 Caen, France. alexandra.gironde@gmail.com.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Girondé
authors.affiliation: UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie &amp; Nutritions N.C.S., Université de Caen Normandie, F-14032 Caen, France. marine.poret@unicaen.fr.
authors.forename: Marine
authors.initials: M
authors.lastname: Poret
authors.affiliation: UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie &amp; Nutritions N.C.S., Université de Caen Normandie, F-14032 Caen, France. philippe.etienne@unicaen.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Etienne
authors.affiliation: UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie &amp; Nutritions N.C.S., Université de Caen Normandie, F-14032 Caen, France. jacques.trouverie@unicaen.fr.
authors.forename: Jacques
authors.initials: J
authors.lastname: Trouverie
authors.affiliation: INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, Agrocampus Ouest, Université de Rennes 1, F-35653 Le Rheu, France. alain.bouchereau@univ-rennes1.fr.
authors.forename: Alain
authors.initials: A
authors.lastname: Bouchereau
authors.affiliation: INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, Agrocampus Ouest, Université de Rennes 1, F-35653 Le Rheu, France. francoise.le-caherec@univ-rennes1.fr.
authors.forename: Françoise
authors.initials: F
authors.lastname: Le Cahérec
authors.affiliation: INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, Agrocampus Ouest, Université de Rennes 1, F-35653 Le Rheu, France. laurent.leport@univ-rennes1.fr.
authors.forename: Laurent
authors.initials: L
authors.lastname: Leport
authors.affiliation: INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, Agrocampus Ouest, Université de Rennes 1, F-35653 Le Rheu, France. marie-francoise.niogret@univ-rennes1.fr.
authors.forename: Marie-Françoise
authors.initials: MF
authors.lastname: Niogret
authors.affiliation: UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie &amp; Nutritions N.C.S., Université de Caen Normandie, F-14032 Caen, France. jean-christophe.avice@unicaen.fr.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Avice
keywords: Brassica napus; N remobilization; acidic proteases; genotypic variability; proteolysis