CRISPR-editing rice crops: Mitigating the impacts of rice disease in sub-Saharan Africa

Rice is a key staple crop in sub-Saharan Africa, with more than 60% of rice produced consumed there. However, the Rice Yellow Mottle Virus (RYMV) causes a disease that has the propensity to wipe out African rice crops. This disease, which is often considered the most dominant rice disease affecting irrigated and lowland ecologies, has since its discovery been observed in nearly all of Africa’s rice-producing countries.

In this study, published in the Plant Biotechnology Journal, researchers aimed to develop resistance to the disease.

The cost of the virus

Many of Africa’s rice producers have barely a hectare of land to themselves. In this environment, between 10% and 100% of rice yield is regularly lost to disease, putting strain on food security.

“RYMV has an impact on food security and poverty of smallholder farmers. The impact is variable from one year to the other, dependent of various factors, and is very difficult to quantify precisely. However the disease is often described by African smallholder farmers as one of the main disease of rice and, considering the importance of rice in Africa and in the world, some authors included RYMV in the Top Ten of economically important plant viruses,” Laurence Albar, one of the researchers, told FoodNavigator.

Developing resistance

There are currently three resistance genes to RYMV, and mutations in just one of these genes enables a rice strain to achieve resistance. 

While one domesticated rice species, Oryza glaberrima, also known as African rice, has developed resistance in some cases, it is low yielding and not widely used. However, resistance in the higher yielding and more widely used Oryza sativa, is extremely low. While O. glaberrima has almost the full spectrum of resistance genes, the higher-yielding O. sativa does not.