Chinese scientists identify genes for more heat-tolerant rice

SHANGHAI, June 18 (Xinhua) -- Chinese scientists found two genes in rice that can make the staple crop more heat-resistant, providing a new way for breeding highly thermotolerant crops.

The researchers from the Shanghai Institute of Plant Physiology and Ecology under the Chinese Academy of Sciences and Shanghai Jiao Tong University revealed the mechanism by which the rice's cell membrane senses external heat-stress signals before communicating with chloroplasts. It is the organ where photosynthesis takes place to orchestrate heat tolerance.

Too much heat can damage a plant's chloroplasts. When temperatures exceed a crop's usual tolerance, its yields tend to drop.

The researchers identified a locus with two genes, Thermo-tolerance 3.1 (TT3.1) and Thermo-tolerance 3.2 (TT3.2). They interact in concert to enhance rice thermotolerance and reduce grain-yield losses caused by heat stress.

The researchers found that accumulated TT3.2 triggers chloroplast damage regarding heat stress, but, in that scenario, TT3.1 can serve as a remedy.

Upon heat stress, TT3.1, a potential thermosensor, will remove the cell membrane from the cell to degrade the mature TT3.2 proteins, according to the study published on Friday in the journal Science.

"The study elucidates a fresh molecular mechanism that links plant cell membranes with the chloroplast in responding to heating signals," said the paper's co-corresponding author Lin Hongxuan with the Shanghai Institute of Plant Physiology and Ecology.

Then, the researchers used hybridization to translate the TT3 locus of African rice into Asian species.

The field test has shown that the new species is more heat tolerant. It can withstand heat at 38 degrees Celsius without crop failure, while the output of normal species would be reduced above 35 degrees Celsius, said the researchers.

The newly-found gene might also be used in other plants, including wheat, maize, bean, and vegetables, to cultivate heat-tolerant strains, according to the researchers.