A research team in Shanghai has identified and cloned a "longevity gene" in wild rice that determines its perennial nature, a breakthrough with significant implications for ecological agriculture and sustainable development.

The discovery could make it possible to transform rice from an annual crop into a perennial one.

Scientists say that if the trait can be introduced into widely cultivated annual rice varieties, it could produce rice that is planted only once. Under suitable conditions, the crop could regrow each year without repeated planting or tilling, allowing multiple harvests.

Such a development would reduce labor demands, help ensure food security and contribute to carbon sequestration.

The team said its findings provide valuable genetic information and resources to achieve that goal, adding that substantial progress has already been made.

"By introducing the 'longevity gene', known as EBT1, into existing high-yield cultivated rice, we successfully created a perennial 'wild-like rice' that has survived in fields for more than two years in Hainan province. Observations are ongoing," said Han Bin, a lead scientist at the Chinese Academy of Sciences' Center for Excellence in Molecular Plant Sciences.

Scientists note that cultivated rice was originally domesticated from wild rice. During domestication, early humans prioritized traits that enabled annual rice to grow quickly and produce more grains, inadvertently leading to the loss of the "longevity gene".

In the study, researchers solved a key evolutionary puzzle, finding that a mutation in the EBT1 gene played a critical role in transforming rice from a perennial plant into an annual crop during early domestication.

They also found that the longevity of perennial wild rice lies in its ability to reverse its developmental program.

Plants typically go through four stages: seed germination, vegetative growth, reproductive growth and death. Perennial wild rice, however, can revert from the reproductive stage back to the vegetative stage, producing new stems, branches and leaves while effectively resetting its physiological age, according to researchers.

"Such a reversal occurs every three to four months, allowing for 'one planting, multiple harvests'," said Wang Jiawei, another lead scientist on the study.

The findings, the result of eight years of research, were featured on the cover of the journal Science on Friday.

"Imagine a grain that came up every year, with no need to till fields and replant each crop. Farmers would save labor, and soil erosion would slow," the journal said in a correspondence.

Field trials have shown encouraging signs of the crop's longevity. The bred rice is highly prolific, producing about 70 secondary tillers, compared with about a dozen produced by its wild-type parent, according to the correspondence.

zhouwenting@chinadaily.com.cn