Characterization of senescence-associated protease activities involved in the efficient protein remobilization during leaf senescence of winter oilseed rape

• Published in: Plant science (Limerick) Vol. 246; pp. 139 - 153
• Main Authors: Poret, Marine, Chandrasekar, Balakumaran, van der Hoorn, Renier A.L., Avice, Jean-Christophe
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 01.05.2016; Elsevier
• Subjects: Brassica napus; Brassica napus - growth & development; Brassica napus - metabolism; Chromatography, Liquid; Cysteine proteases; Hydrogen-Ion Concentration; Life Sciences; Nitrogen remobilization efficiency; Peptide Hydrolases - metabolism; Plant Leaves - enzymology; Plant Leaves - growth & development; Plant Leaves - metabolism; Plant Proteins - metabolism; Protease activity; Proteasome Endopeptidase Complex - metabolism; Proteolysis; Ribulose-Bisphosphate Carboxylase - metabolism; Seasons; Seeds - metabolism; Senescence-associated proteases; Solubility; Soluble proteins; Tandem Mass Spectrometry; Up-Regulation; Vacuoles - metabolism; Vegetal Biology; NPC; NRE; LN; Nitrogen remobilization efficiency; SAP; HN; SAV; VPE; PLCP; N; Cysteine proteases; Soluble proteins; Senescence-associated proteases; POPL; NUE; Protease activity; SCPL; CP; AP; CXE; CCV; Brassica napus; MES; RuBisCO (RBC); RBCL
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/j.plantsci.2016.02.011

•Aspartic proteases and proteasome were active during leaf senescence in oilseed rape.•Activities of serine proteases increased when protein remobilization occurred in leaf.•High protein remobilization is linked to an increase of cysteine proteases activities.•Papain-like Cys proteases and vacuolar processing enzymes are the major cys proteases 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.