title: Characterization of senescence-associated protease activities involved in the efficient protein remobilization during leaf senescence of winter oilseed rape.
abstract: Oilseed rape (Brassica napus L.) is a crop plant characterized by a poor nitrogen (N) use efficiency that is mainly due to low N remobilization efficiency during the sequential leaf senescence of the vegetative stage. As a high leaf N remobilization efficiency was strongly linked to a high remobilization of proteins during leaf senescence of rapeseed, our objective was to identify senescence-associated protease activities implicated in the protein degradation. To reach this goal, leaf senescence processes and protease activities were investigated in a mature leaf becoming senescent in plants subjected to ample or low nitrate supply. The characterization of protease activities was performed by using in vitro analysis of RuBisCO degradation with or without inhibitors of specific protease classes followed by a protease activity profiling using activity-dependent probes. As expected, the mature leaf became senescent regardless of the nitrate treatment, and nitrate limitation enhanced the senescence processes associated with an enhanced degradation of soluble proteins. The characterization of protease activities revealed that: (i) aspartic proteases and the proteasome were active during senescence regardless of nitrate supply, and (ii) the activities of serine proteases and particularly cysteine proteases (Papain-like Cys proteases and vacuolar processing enzymes) increased when protein remobilization associated with senescence was accelerated by nitrate limitation. Short statement: Serine and particularly cysteine proteases (both PLCPs and VPEs) seem to play a crucial role in the efficient protein remobilization when leaf senescence of oilseed rape was accelerated by nitrate limitation.
authors.affiliation: Université de Caen 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. Electronic address: marine.poret@unicaen.fr.
authors.forename: Marine
authors.initials: M
authors.lastname: Poret
authors.affiliation: The Plant Chemetics Laboratory, Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, United Kingdom; The Plant Chemetics Laboratory, Max Planck Institute for Plant Breeding Research, Carl-von-Linne Weg 10, 50829 Cologne, Germany. Electronic address: balakumaran.chandrasekar@plants.ox.ac.uk.
authors.forename: Balakumaran
authors.initials: B
authors.lastname: Chandrasekar
authors.affiliation: The Plant Chemetics Laboratory, Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, United Kingdom. Electronic address: renier.vanderhoorn@plants.ox.ac.uk.
authors.forename: Renier A L
authors.initials: RAL
authors.lastname: van der Hoorn
authors.affiliation: Université de Caen 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. Electronic address: jean-christophe.avice@unicaen.fr.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Avice
mesh_terms: D029688:Brassica napus / Q000254:growth & development / Q000378:metabolism*; D002853:Chromatography, Liquid; D006863:Hydrogen-Ion Concentration; D010447:Peptide Hydrolases / Q000378:metabolism*; D018515:Plant Leaves / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D059748:Proteolysis; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism; D012621:Seasons; D012639:Seeds / Q000378:metabolism; D012995:Solubility; D053719:Tandem Mass Spectrometry; D015854:Up-Regulation; D014617:Vacuoles / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D010447:Peptide Hydrolases; D046988:Proteasome Endopeptidase Complex; D012273:Ribulose-Bisphosphate Carboxylase
keywords: Brassica napus; Cysteine proteases; Nitrogen remobilization efficiency; Protease activity; Senescence-associated proteases; Soluble proteins