Bacterial blight (Xanthomonas oryzae) disease lesions on rice crop.

Rice infested with bacterial blight, which can cause crop losses as high as 75%. Credit: Nigel Cattlin/Alamy

CRISPR-Cas9 genome editing

A crop that feeds billions freed from blight by CRISPR

Bacteria that infect rice are thwarted by changes to rice genes involved in sugar transport.

Genome editing has made one of the world’s most important crops resistant to a devastating bacterial infection.

Bacterial blight, which is caused by Xanthomonas oryzae pathovar oryzae (Xoo), can slash farmers’ yields of rice, which is a staple food for billions of people. Seeking to lessen the blight’s impact, Ricardo Oliva at the International Rice Research Institute in Manila and his colleagues studied Xoo genes that code for proteins called TALEs. Xoo use these proteins to turn on the plant’s SWEET genes, which produce sugar-transporting molecules. This gives the bacteria access to nutrients in the plants’ leaves.

The team’s analysis of 63 Xoo strains revealed that each strain has one or more TALE variants. Each variant can activate at least one of three SWEET genes.

The researchers used CRISPR–Cas9 gene editing to modify three SWEET genes found in rice varieties that are grown across Asia and Africa. Bacterial TALE proteins could no longer activate the edited genes, and the team found that rice plants with these engineered genes were resistant to at least 95 Xoo strains.