Seed quality in B. napus

The increased production of rapeseed oil is a major goal and can go through the increase of seed yield and / or oil content in the seed. In addition, the competitiveness of the rapeseed crop will be achieved only if the energy cost of production (inputs, extraction process) is reduced and balanced by a high added value of the co-products.

Research and main results

Genetic and functional analyses of seed oil content Oil seed content trait is under complex genetic determinism: 14 genomic regions were identified in the 'Darmor-bzh x Yudal' doubled haploid population (Delourme et al. 2006). Molecular markers were developed to refine the targeted regions based on candidate genes, the Brassica/Arabidopsis synteny and more recently the sequencing data from the Brassica genomes. In addition, an initial characterization of genetic diversity for the oil content has been initiated using a panel of around 100 rapeseed accessions and will help to bring results on the validation of targeted regions.

Impact of the composition and/or structure of the oil bodies on seed crushing ability

Better knowledge of the biogenesis and the accumulation of the oil bodies (OBs) would provide keys to modify their stability and therefore to facilitate the oil extraction process. To this purpose an exhaustive description of the protein composition from rapeseed OBs was achieved by combination of proteomic and genomic tools. Genomic analysis led to the identification of major proteins, including oleosins, steroleosins and caleosins. Alignments of amino acid sequences revealed a high level of conservation between Arabidopsis and Brassica napus. Future work will include the production and analysis of transgenic rapeseeds with modified expression of OB protein genes.

Biochemical and molecular analyses of flavonoid metabolism in rapeseed

The profiling of seed coat flavonoids by LC-ESI-MSn was established in 8 black-seeded B. napus genotypes, during seed development (Auger et al. 2010). Sixteen different flavonoids including (-)-epicatechin, procyanidins and flavonols were identified and quantified. High amounts of PCs accumulated in the seed coat, with solvent-soluble polymers of (-)-epicatechin reaching up to 10% of the seed coat weight during seed maturation. In addition, variability for both PC and flavonol contents was observed within the different genotypes. In parallel, a cadidate gene approach was initiated. The orthologs of seven Arabidopsis TRANSPARENT TESTA (TT) were cloned in B. napus. A comparative genomic study revealed (1) a high conservation in the amino acid sequences between the Brassicacea and (2) a syntenic location on the respective genomic sequences. Finally, the activation profile of the promotors Bna.BAN was monitored in planta with « promotor-reporter » fusions in rapeseed and in Arabidopsis (Auger et al., 2009; Nesi et al., 2009).

Main references

Jolivet et al. Deciphering the structural organization of the oil bodies in the Brassica napus seed as a mean to improve the oil extraction yield. Industrial Crops and Products 44 (2013) 549-557. DOI

Jolivet et al. Oil body proteins sequentially accumulate throughout seed development in Brassica napus. J Plant Physiol. 2011 Nov 15;168(17):2015-20. DOI

Auger B. et al. A detailed survey of seed coat flavonoids in developing seeds of Brassica napus L. J Agric Food Chem. 2010 May 26;58(10):6246-56. DOI

Auger B. et al. Brassica orthologs from BANYULS belong to a small multigene family, which is involved in procyanidin accumulation in the seed. Planta. 2009 Nov;230(6):1167-83. DOI

Nesi N. et al. The promoter of the Arabidopsis thaliana BAN gene is active in proanthocyanidin-accumulating cells of the Brassica napus seed coat. Plant Cell Rep. 2009 Apr;28(4):601-17. DOI

Jolivet P. et al. Protein composition of oil bodies from mature Brassica napus seeds. Proteomics. 2009 Jun;9(12):3268-84. DOI 

Nesi N. et al. Genetic and molecular approaches to improve nutritional value of Brassica napus L. seed. C R Biol. 2008 Oct;331(10):763-71. DOI

Delourme R. et al. Genetic control of oil content in oilseed rape (Brassica napus L.). Theor Appl Genet. 2006 Nov;113(7):1331-45.

Lepiniec L. et al. Genetics and biochemistry of seed flavonoids. Annu Rev Plant Biol. 2006;57:405-30. Review

Collaborations

• UMR1318 IJPB, INRA Versailles – AgroParisTech, France
• UR117 Cidricoles, Biotransformation des Fruits et Légumes, INRA Rennes, France
• UR1268 Biopolymères Interactions Assemblages, INRA Nantes, France
• CNRGV Centre National de Ressources en Génomique Végétale, INRA Toulouse, France
• UMR1165 Génomique Végétale, INRA Evry – CNRS, France
• Plate-forme d'Histo-pathologie / IFR140, Univ. Rennes1, France
• Biogemma, Mondonville et Clermont-Ferrand, France
• CETIOM, Pessac, France
• Univ. Bielefeld, Germany
• Univ. Giessen, Germany

Fundings/Projects

• OSRCROP (ANR Genoplante 2006-2008): « Carbon balance in seed filling of oilseed rape (Brassica napus) - Controlling reserve accumulation in oil and protein » (coordination J. Wilmer, Biogemma)
• GENEBODIES (ANR Genoplante 2006-2008): « Structural and functional study of oil and protein storage bodies in A. thaliana and B. napus: towards environmental friendly oil and protein extraction process» (coordination T. Chardot, INRA Versailles)
• GENERGY (ANR Genoplante 2008-2012): « Improvement of the oil yield of the rapeseed crop in the context of bio fuel production » (coordination N. Nesi, INRA Rennes)
• RAPSODYN (Investissements d’Avenir 2012-2019): « Optimisation of the rapeseed oil content and yield under low nitrogen input : improving breeding of adapted varieties using genetics and genomics» (coordination N. Nesi, INRA Rennes)