With its yellow flowers, even city dwellers can recognize fields of canola (Brassica napus L.). An oilseed crop cultivated around the world, this brassicaceous1 plant is derived from the cross of a cabbage with a turnip rape, occurring approximately 7,500 years ago and probably favored by humans. In the context of the Seq-Poly-Nap project, funded primarily by the National Research Agency (ANR), researchers from INRA, the CEA-IG (Genoscope), the CNRS, and the Université d’Evry have produced in collaboration with their foreign colleagues the reference sequence of the canola genome, as well as several varieties of the species (including rutabaga).
The Genoscope has developed an original strategy and created ad hoc bioinformatics tools to divide up the sequences read from the 19 chromosomes of the plant (9 coming from cabbage and 10 from turnip rape). The first observation: the double genome of canola, which in fact results from the accumulation of 72 ancestral genomes, has more than 101,000 genes! The vast majority of them are duplicated, existing in two copies of close or almost identical sequences. These two copies are expressed in almost all cases, jointly participating in the function of the gene. Researchers see this as an important reservoir of diversity, adaptation and improvement. With the primary gene function being governed by one copy, the second copy is available for restructuring and mutating, which can bring out new functions.
Cultivated on a large scale since only recent times, canola still has a high potential for genetic improvement. This reference sequence will facilitate the identification of genes of agronomic interest, in order to improve oil content and composition, resistance to pathogens, cold tolerance, and the performance/efficiency of using nitrates in the soil.
1 Formerly referred to as the Cruciferae, the Brassicaceae family includes cabbage, turnips, mustard, cress, radishes, etc.