Format

Send to

Choose Destination
J Exp Bot. 2014 Jul;65(14):3813-24. doi: 10.1093/jxb/eru177. Epub 2014 Apr 30.

Leaf senescence and nitrogen remobilization efficiency in oilseed rape (Brassica napus L.).

Author information

1
Normandie University, 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.
2
Normandie University, 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.

Abstract

Despite its worldwide economic importance for food (oil, meal) and non-food (green energy and chemistry) uses, oilseed rape has a low nitrogen (N) use efficiency (NUE), mainly due to the low N remobilization efficiency (NRE) observed during the vegetative phase when sequential leaf senescence occurs. Assuming that improvement of NRE is the main lever for NUE optimization, unravelling the cellular mechanisms responsible for the recycling of proteins (the main N source in leaf) during sequential senescence is a prerequisite for identifying the physiological and molecular determinants that are associated with high NRE. The development of a relevant molecular indicator (SAG12/Cab) of leaf senescence progression in combination with a (15)N-labelling method were used to decipher the N remobilization associated with sequential senescence and to determine modulation of this process by abiotic factors especially N deficiency. Interestingly, in young leaves, N starvation delayed senescence and induced BnD22, a water-soluble chlorophyll-binding protein that acts against oxidative alterations of chlorophylls and exhibits a protease inhibitor activity. Through its dual function, BnD22 may help to sustain sink growth of stressed plants and contribute to a better utilization of N recycled from senescent leaves, a physiological trait that could improve NUE. Proteomics approaches have revealed that proteolysis involves chloroplastic FtsH protease in the early stages of senescence, aspartic protease during the course of leaf senescence, and the proteasome β1 subunit, mitochondria processing protease and SAG12 (cysteine protease) during the later senescence phases. Overall, the results constitute interesting pathways for screening genotypes with high NRE and NUE.

KEYWORDS:

Brassica napus; N remobilization efficiency; N transport; N use efficiency; leaf senescence; proteolysis.

PMID:
24790115
DOI:
10.1093/jxb/eru177
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Silverchair Information Systems
Loading ...
Support Center