Farmers facing extreme weather conditions associated with climate change could benefit from the finding that a gene that 'waterproofs' rice plants also appears to protect them from drought.

The Sub1a gene, which naturally occurs in some low-yielding varieties in India, was discovered in the 1990s at the International Rice Research Institute (IRRI), in the Philippines. Subsequent research showed that the gene bred into the high-yielding varieties can protect the submerged rice in over-flooded paddies. Following successful field trials the improved rice has been rolled out in Bangladesh, India and the Philippines.

But researchers from the US-based University of California, Riverside (UCR) wanted to test whether the insertion of the waterproofing gene was detrimental to how the rice responds to other stresses, such as drought.

They found that Sub1A coordinates how the plant cells respond to dehydration, which occurs in droughts, but also following a period of submergence in floods. The gene helps rice recover after a flood, when it dehydrates after sudden exposure to drier conditions, and the same dehydration happens in droughts.

"What was really neat about the study was that we realised submergence is a very complicated stress," said Julia Bailey-Serres, a professor of genetics at UCR and the lead author of the study. After being submerged, rice experiences dehydration as it would during a drought, and Sub1a's task is to help it recover.

The effect has been seen in the laboratory and the greenhouse so far, and IRRI is planning follow-up research later this year, said Abdelbagi Ismail, senior scientist at IRRI who was involved in the Sub1a research and is now the coordinator of the project on stress-tolerant rice funded by the Bill & Melinda Gates Foundation.

He said the discovery — if repeated in the field — opened up new possibilities for rice breeding and farming.

"If you look at rice-growing areas, many of them have the same two stresses [floods and droughts]," Ismail said.

"Climate change will further increase the variation in the weather worldwide as it can be very wet and dry all in a very short period," he said. "Thus we need new varieties [of crops], especially those which can tolerate both [stresses]."

Three billion people worldwide depend on rice as a staple food. The crop is vulnerable to various environmental stresses, but Ismail said that advances in breeding stress-tolerant varieties are enabling production to keep up with the rising demand.