The Healthy Crops team, with support from the Bill & Melinda Gates Foundation, have used gene tools to develop new varieties of disease-resistant rice that U.S. and Colombian regulators have determined are equivalent to what could be accomplished with conventional breeding.
Bacterial blight can reduce rice yields by up to 70%, with the heaviest losses typically experienced by smallholder rice growers in low- and middle-income countries. The researchers turned to gene editing to develop disease-resistant varieties as a way to provide farmers with a safe, affordable, effective solution.
“We first set about to understand the gene the bacteria use to make the plant vulnerable to its disease,” said Dr. Bing Yang, a researcher with the University of Missouri Bond Life Sciences Center professor, Division of Plant Sciences and member, Donald Danforth Plant Science Center in St. Louis. “We then used our CRISPR technology precisely to remove the element in the gene to avoid the pathway the pathogen takes that makes the plants susceptible to blight.”
The team used gene editing to create rice lines in elite varieties comparable to naturally occurring variants. The rulings from the U.S. Department of Agriculture and the corresponding authority in Colombia, the Instituto Colombiano Agropecuario, clear the way for field tests to select the best material for distribution to breeders in those two countries.
The improvements made through gene editing, which did not introduce any DNA into the plants. The method focused on “promoter regions” in three genes targeted by the bacterium Xanthomonas oryzae pathovar oryzae. The research was described in an article in Nature Biotechnology in 2019.
In the wake of the ruling from U.S. and Colombian officials, the new blight-resistant varieties can now be used to introduce the resistance trait into other types of rice using standard breeding techniques.
“It’s exciting to use science and technology to do to help farmers protect and improve their rice production,” Yang said. “We hope to work closely with the local institutions in the next phase to introduce these into the varieties of rice small farmers use.”
The Healthy Crops Team has no commercial interest in its work.
This article was contributed by the Danforth Plant Sciences Center.