1The announced sequencing of the first plant genome in 2000 struck fear into the heart of the scientific community. What would happen if a private consortium were to sequence the DNA of a plant of agronomic interest, a plant as vital as rice? In 1997, an international consortium, financed by public funds and involving 10 countries, was created in an attempt to accomplish a scientific feat. At the time, the technology was costly, slow and complex. One country alone would have been unable to complete rice sequencing, the genome of which is equivalent to four times that of Arabidopsis.

Improving rice varieties in Vietnam.

2This is why IRD, who had been working on the diversity of wild and cultivated rice varieties since the 1970s, turned to the Génoscope, responsible for the sequencing of the human genome, to ensure France’s involvement in the consortium. The different participating States shared the rice genome between them. It was incumbent upon France to sequence chromosome 12. This investment paid off: in 2005, the entire rice genome was published by this consortium in Nature magazine, while the sequences obtained by the private sector were incomplete or of poorer quality.

Rice panicle.

••• IRD, CNRS and Génoscope sequenced rice chromosome 12 •••

3Thanks to technical progress and a drop in sequencing costs, other species such as millet and the coffee tree were later sequenced by IRD and its partners. Better still, thousands of individuals from the same species were screened, notably for rice and millet, after which it became possible to reflect genetic diversity within species and identify genes likely to be selected to increase productivity, adaptability or disease resistance. This research enabled scientists to identify genes of interest in the African species of cultivated rice which were transferred to Asian rice, such as resistance genes to combat rice yellow mottle virus, a viral disease which affects rice paddies in Africa.

“IRD’s analysis of the rice genome contributed to a better understanding of the diversity of cultivars in the African cultivated rice species, while promoting AfricaRice’s development of NERICA varieties resulting from cross-breeding between the two cultivated rice species.” 
Moussa Sié, formerly head of the Africa-wide Rice Breeding Task Force’s Africa Rice Center (AfricaRice), Bouaké, Côte d’Ivoire