The contrasting N management of two oilseed rape genotypes reveals the mechanisms of proteolysis associated with leaf N remobilization and the respective contributions of leaves and stems to N storage and remobilization during seed filling

BMC Plant Biology

Research Article

Fabienne Soulay¹  Céline Masclaux-Daubresse¹  Nathalie Nesi²  Marie-Françoise Niogret²  Deleu Carole²  Françoise Le Cahérec²  Laurent Leport²  Alain Bouchereau²  Mathilde Orsel³  Jacques Trouverie⁴  Jean-Christophe Avice⁴  Alexandra Girondé⁴  Philippe Etienne⁴ 

[1]Département Adaptation des Plantes à l’Environnement, UMR 1318, INRA, Institut Jean-Pierre Bourgin, RD10, 78026, Versailles, Cedex, France

[2]INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, INRA, Agrocampus Ouest, Université de Rennes 1, F-35653, Le Rheu, France

[3]INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, INRA, Agrocampus Ouest, Université de Rennes 1, F-35653, Le Rheu, France

[4]UMR 1345 Institut de Recherche en Horticulture et Semences, SFR 4207 QUASAV, PRES L’UNAM, Université d’Angers, F-49045, Angers, France

[5]UMR 1345 Institut de Recherche en Horticulture et Semences, AgroCampus-Ouest, F-49045, Angers, France

[6]Université de Caen Basse-Normandie, F-14032, Caen, France

[7]UCBN, UMR INRA–UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., F-14032, Caen, France

[8]INRA, UMR INRA–UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., F-14032, Caen, France

关键词: Brassica napus;    Leaf senescence;    N remobilization efficiency;    N use efficiency;    Proteolysis;    Proteasome;   

DOI  :  10.1186/s12870-015-0437-1

 received in 2014-12-15, accepted in 2015-01-23,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundOilseed rape is the third largest oleaginous crop in the world but requires high levels of N fertilizer of which only 50% is recovered in seeds. This weak N use efficiency is associated with a low foliar N remobilization, leading to a significant return of N to the soil and a risk of pollution. Contrary to what is observed during senescence in the vegetative stages, N remobilization from stems and leaves is considered efficient during monocarpic senescence. However, the contribution of stems towards N management and the cellular mechanisms involved in foliar remobilization remain largely unknown. To reach this goal, the N fluxes at the whole plant level from bolting to mature seeds and the processes involved in leaf N remobilization and proteolysis were investigated in two contrasting genotypes (Aviso and Oase) cultivated under ample or restricted nitrate supply.ResultsDuring seed filling in both N conditions, Oase efficiently allocated the N from uptake to seeds while Aviso favoured a better N remobilization from stems and leaves towards seeds. Nitrate restriction decreased seed yield and oil quality for both genotypes but Aviso had the best seed N filling. Under N limitation, Aviso had a better N remobilization from leaves to stems before the onset of seed filling. Afterwards, the higher N remobilization from stems and leaves of Aviso led to a higher final N amount in seeds. This high leaf N remobilization is associated with a better degradation/export of insoluble proteins, oligopeptides, nitrate and/or ammonia. By using an original method based on the determination of Rubisco degradation in the presence of inhibitors of proteases, efficient proteolysis associated with cysteine proteases and proteasome activities was identified as the mechanism of N remobilization.ConclusionThe results confirm the importance of foliar N remobilization after bolting to satisfy seed filling and highlight that an efficient proteolysis is mainly associated with (i) cysteine proteases and proteasome activities and (ii) a fine coordination between proteolysis and export mechanisms. In addition, the stem may act as transient storage organs in the case of an asynchronism between leaf N remobilization and N demand for seed filling.

【 授权许可】

Unknown   
© Girondé et al.; licensee BioMed Central. 2015. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.