An international consortium of over 30 research institutes -among which are three French research centers – has succeeded in sequencing the entire genome of Brassica napus L, more commonly known as rapeseed. Rapeseed – the plant from which we derive canola oil – is the most important oilseed crop in Europe, Canada, and Australia and has a gene density of 101,000, four times that of a human being. Such a milestone discovery is sure to deepen our understanding of the development of polyploidy crops (plants that contain more than two paired sets of chromosomes). Better knowledge of this complicated form of reproduction will allow us to trace the complicated genetic genealogy of these plants as well as to improve upon their growing efficiency.
The French National Research Agency (ANR) was the primary financier for this project “Seq-Poly-Nap,” which coordinated groundbreaking scientific research teams from the French National Institute for Agronomic Research (INRA), CEA (Genoscope), the French National Center for Scientific Research (CNRS) and the University of Evry, among others. Head research coordinator Boulos Chalhoub said “the main difficulty for rapeseed has been to differentiate its different sub genomes… . It has been achieved by the development of an original sequencing strategy, bioinformatics tools, and the analysis of duplicated gene expression and their regulation.” Being the first recent polyploidy genome to be completely sequenced, scientists can use the rapeseed genome map as a point of comparison to its parental relative species.
Rapeseed has more informational potential than do its relatives because it is a recent polyploidy. All flowering plants originated from polyploidization events, the majority of which did so millions of years ago. Rapeseed, on the other hand, originated around 7,500 years ago and is thus easier to trace back to the moment of speciation, or the formation of a new species. The moment of speciation and the mapping of subsequent evolutionary developments will give scientists insight into the evolutionary processes of the crop with the end goal of genetic improvement, in this case.
What they found was that the rapeseed crop preserved the genes of its parents almost identically during its first few thousand years of existence. Its genes are almost perfectly duplicated, with highly similar DNA sequences. Chalhoub surmises that “…duplicated genes are an important part of diversification, emergence of new functions, [and] adaptation and improvement of the species.”
How would the adaptation and diversification of rapeseed benefit us?
Rapeseed oils are rich in non-saturated fatty acids, vitamin D and Omega 3, which makes them unusually healthy as far as oils are concerned. With the genome of rapeseed mapped in its entirety, we will have the opportunity to target genes that could, for example, improve content and make-up of the oil, crop resistance, weather resilience, yield and so on. The INRA is already using these published findings as a reference and resource for many projects in the framework of a more sustainable agriculture.