Climate change is increasing both the severity and frequency of extreme weather events, including floods. That's a problem for many farmers, since rice is the only major food crop that's resilient to flooding. A new study, published in Science, however, identified genetic clues to this resilience that may help scientists improve the prospects for other crops.
"Our work is the most comprehensive look yet across species into what's really going on under the hood as plants respond to flooding," says Roger Deal, associate professor of biology at Emory University and a lead author of the study. "Understanding the mechanism for flooding tolerance is the first step in understanding how you might increase it in plants that lack it."
Rice was domesticated from wild species that grew in tropical regions, where it adapted to endure monsoons and waterlogging. The Science research looked at how other crops compare to rice when submerged in water. The plants included species with a range of flooding tolerance, from barrel clover (which is similar to alfalfa), to domesticated tomato plants, to a wild-growing tomato that is adapted for a desert environment.
The results showed that, although evolution separated the ancestors of rice and these other species as many as 180 million years ago, they all share at least 68 families of genes that are activated in response to flooding.
"That was surprising," Deal says. "We thought we'd see different gene expression responses among these species related to their adaptation to wet or dry conditions. Instead, what was really different was that rice had far and away the most rapid and synchronous response. In comparison, the other plants' responses were piecemeal and haphazard."
