New gene found to shield rice from global pathogen

Chinese scientists have identified a new gene that shields rice from a destructive bacterial disease, a breakthrough that could protect global food supplies as climate change makes crops more vulnerable to extreme weather.

The discovery, published on Wednesday in the journal Nature, offers a potential solution to bacterial leaf blight. This disease destroys the plant's ability to photosynthesize, leading to shriveled grains and, in severe cases, total crop failure.

Researchers from the Center for Excellence in Molecular Plant Sciences at the Chinese Academy of Sciences, in collaboration with Shanghai Jiao Tong University and Zhejiang University, spent two decades searching for a way to stop the pathogen. The disease has become a global threat, fueled by rising temperatures and the frequent typhoons and floods that help the bacteria spread.

The team screened 3,000 different types of rice varieties before identifying a specific gene named Xa48. The scientists found that Xa48 acts like a specialized security system. It recognizes a specific protein produced by the bacteria — called an effector protein — and triggers the plant's immune response to fight back.

While a previous resistance gene mainly targeted bacterial strains found in Southeast Asia, the new Xa48 gene is particularly effective against variants found in Northeast Asia.

By combining this new discovery with an older and more general resistance gene, Xa21, the researchers created a "dual-layer" immune network.

This mimics the hardy defense systems found in wild rice, which have often been lost in modern crops as farmers bred them to prioritize high yields over disease resistance.

The breakthrough is already moving from the lab to the field. Multiple seed companies and national institutes are using the gene to breed new rice varieties.

"Improving disease resistance of crops will also reduce pesticide use, contributing to greener agricultural production," said He Zuhua, a researcher and co-corresponding author of the study.

Despite current pesticide use, experts estimate that China loses at least 18 million metric tons of grain annually due to pests and diseases.

The new rice lines developed through this study have shown the ability to maintain high yields and strong resistance even when subjected to the stress of floods and typhoons.

"This is the first time in crops that the combination of two immune networks has been shown to reconstruct such broad-spectrum disease resistance like wild rice," said Lin Hui, a co-first author of the paper.

The research is now being applied by major industry players, including Longping High-Tech Agriculture Co and the China National Rice Research Institute, to develop the next generation of resilient crops.

zhouwenting@chinadaily.com.cn