Scientists at the French Institute of Agronomic Research (INRA) have sequenced the genome of the sunflower, a major achievement that will help improve varietal sunflower breeding programs. This is the first time that the sunflower’s genome has been completely sequenced, meaning that all of the plant’s genes were decoded, assembled and put in the correct order.
The sunflower is a large-scale crop, of which 80% is produced in Europe, and which has strong potential for genetic advancement. The precise mapping of all of the sunflower’s genes opens new possibilities for identifying genes of agronomic interest or providing interesting prospects for industry and food. The result will allow for an acceleration of national and international programs for sunflower selection and marketing improved varietals that are better adapted to different agricultural practices.
The project was completed by INRA in collaboration with the SUNRISE project, whose goal is to develop at type of sunflower that is resistant to climate change. The sunflower, which already is a plant that has low demand for water, is one of the best possible solutions available to push the plant-growing industry to be better adapted to potential disruptions caused be climate change. The global production of oil seeds, like sunflower seeds, is expected to see increased demand in the coming years, due to increased use in human and animal food products and the development of biofuels. Because of this, it is crucial that annual yields can be sustainably increased using innovative methods that respond to climate change.
In order to sequence the genome, the main difficulty was in assembling the genes in the correct order, like the pieces of a puzzle. This giant puzzle, 20% larger than the human genome, is even more difficult to assemble due to the fact that very large parts of it closely resemble each other. More than 80% of the sunflower genome is composed of parts that are almost identical, making it very difficult for computer programs to differentiate them from each other.
Thanks to an innovative strategy using a latest-generation sequencing robot, scientists were able to acquire a quality reference sequence. The robot, PacBio RS II, is capable of reading DNA sequences that are 100 times longer than previous generations of robots, allowing for the fragments to be more easily assembled in the correct order. This new technology is now being applied to the genome sequencing of other plants of agricultural importance.