Local scientists said yesterday they had identified a plant gene which can help fight rice blast — a major global disease that savages crops — and reduce the use of harmful pesticides.

Rice blast is a fungus and a major scourge in China and worldwide. It can halve grain production. Scientists estimate it destroys global crops by enough rice to feed 85 million people annually.

"Experts estimate that rice blast causes the loss of 3 million tons of rice in China every year,” said He Zuhua, chief scientist of the research team from the Shanghai Institute of Plant Physiology and Ecology at the Chinese Academy of Sciences.

"Although some areas can control the disease, the cost is the large use of pesticides.

"It is a threat to the environment and food security. So we have been looking for disease-resistant genes. By identifying the useful gene and promoting it to more rice products, we can not only control rice blast but also protect the environment and public health.”

The team in 2006 identified a gene, Pigm, which has broad-spectrum resistance.

The scientists then spent a decade to analyze the mechanism of the gene locus and found it encodes two proteins — PigmR and PigmS.

PigmR can defend disease but leads to a drop in production, while PigmS can raise grain production but inhibits the resistance effect of PigmR.

"The two proteins result a good balance by controlling the disease and maintaining good production,” He said.

"By fully understanding the gene, we can guide seed companies and breeders. So far, over 30 domestic companies and breeders have used our discovery for molecular breeding to allow new rice varieties with better disease resistance effects but ideal production.”

The discovery was published in “Science.” (Shanghai Daily)