Scientists are racing to develop strains of "super rice" that can prevent the return of deadly famines to Asia.
Researchers say tough, highly productive rice plants offer the best hope for feeding a world population that will reach 9 billion by 2050. And their quest to create these plants is producing an explosion of scientific papers on rice genetics — three of which appear in leading scientific journals this week.
The push for new rice varieties comes four decades after scientists at the International Rice Research Institute in the Philippines developed a rice plant called IR8 that put its energy into making more rice grains, rather than longer stalks.
"It's essentially doubled rice production in Asia," says Robert Zeigler, IRRI's director general. "It has allowed food supplies in Asia to grow faster, or at least as fast as, population. So we've averted the famines."
But rice production will have to double again by 2050 to keep up with demand. That will mean creating plants that can thrive despite floods, droughts and plant diseases. And those are difficult traits to breed into a plant, Zeigler says.
"Fortunately," he says, scientists have sequenced the complete rice genome and have "a lot of molecular biological tools at our disposal."
The three new papers on rice genetics show what scientists are doing with those tools.
The Snorkel Defense
One study looks at so-called deep-water rice plants, which have evolved several methods to solve the problem of rising floodwaters.
"One of the solutions is that the plant starts to grow very fast in such a way that parts of the shoot will be above the water level, so that that part can function as a sort of snorkel," says Rens Voesenek, a plant biologist at Utrecht University in the Netherlands.
Unfortunately, the snorkel plants don't produce much rice.
But in a paper in the journal Nature, a team from Japan offers a solution to that problem. The team, from Nagoya University, identified genes called SNORKEL1 and SNORKEL2 that control the so-called elongation response in deep-water rice plants.
They showed that putting those genes in typical rice plants caused them to elongate when the water started to rise, says Motoyuki Ashikari, an author of the paper.
This means scientists should be able to produce rice plants that can survive flooding and still produce high yields, Ashikari says.
Surviving Blast
A second study from Japan — this one in the journal Science — identifies a gene that helps rice plants resist something called rice blast.
Blast is a fungus so devastating to crops that the United States considered using it as a biological weapon against Japan during World War II.
In the past, plants bred to resist the fungus-produced rice that didn't taste good. But the new genetic discovery should make it possible to combine resistance and good taste, says Shuichi Fukuoka from the National Institute of Agrobiological Sciences in Tsukuba.
Susan McCouch, a professor of plant breeding and genetics and of plant biology at Cornell University, says the new research represents "a great day for rice genetics."
The papers show that scientists really can help prevent famines, McCouch says. But she adds that rice genetics could help improve the quality of rice, as well as the quantity.
McCouch has a rice paper of her own in the Proceedings of the National Academy of Sciences. It describes the origin of fragrance in rice, specifically the fragrance conferred by a gene called BADH2.
"Fragrance may sound like a luxurious and less than vital characteristic," she says. "But it costs nothing to breed it in."
And now that scientists have found the fragrance gene, they can.
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