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A new kind of genetically modified rice with a higher starch content could produce more food while at the same time reducing the methane, a greenhouse gas, that's emitted when it grows, the journal Nature reported.
Researchers created the genetically modified rice, called SUSIBA2, by using a gene from barley. The barley gene influenced how carbon in the rice plant was distributed. Less carbon in the genetically modified plants went to the roots, which meant that methane-producing bacteria in the soil had fewer nutrients to consume.
Compared to control rice, the genetically modified variety emitted anywhere from 10 percent to less than 1 percent of the methane that normally would have been emitted, depending on the plant's age when the measurement was taken.
Christer Jansson, the director of plant sciences at the Environmental Molecular Sciences Laboratory (EMSL) in Washington and one of the study's authors, called the low-methane rice "very promising."
"Because if [it] can be scaled up to large-scale production in rice paddies in China, that could mean that a significant amount of methane that would otherwise have been released to the atmosphere, is not being released," he told VICE News.
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Methane is not the most abundant greenhouse gas — that's carbon dioxide — but it is a powerful one: the US Environmental Protection Agency estimates that over the course of a century methane can be 25 times as strong as carbon dioxide in its contribution to climate change.
"Methane is the second most important greenhouse gas," Scott Bridgham, a biology and environmental studies professor at the University of Oregon, told VICE News. He studies the methane emitted by wetlands, a prominent source of the gas.
But methane is also released in significant amounts by anthropogenic sources like fossil fuels, landfills, ruminants like cows, and rice cultivation.
According to data from the Intergovernmental Panel on Climate Change, about 60 percent of all methane emissions come from those anthropogenic sources. Rice alone accounts for about 10 percent of the methane created by human activities.
"This study is following on something of a history of field experiments evaluating different kinds of rice varieties — in this case, transgenic [rice] — looking for ways to both increase food production, and reduce methane emissions," Elaine Matthews, a NASA scientist, told VICE News. "One thing it doesn't address is whether this kind of rice really has a chance of being really widely used to gain the methane advantage."
The new genetically modified rice might not see widespread use for multiple reasons, she said. Those include cost, cultural preferences for different kinds of rice, and the fact that the rice industry is complex: The crop is cultivated on many small-scale farms.
David Schubert, a biochemist who works on drug development at the Salk Institute for Biological Studies in California, is concerned about the safety of genetically modified crops.
"When you alter the gene expression in any organism you get a lot of changes that you can't predict," Schubert told VICE News.
Kenneth Boote, a crop physiologist and professor at the University of Florida, said that he doesn't have any problem with genetically modified crops. But he remains skeptical of this new study, in part because he said increasing the amount of starch in the rice plant could actually reduce the rice's protein levels. He also questioned whether the new variety would actually reduce methane emissions, since the gas is also emitted after the rice is harvested and the stalks are left behind.
"I worry a little bit about potted plant experiments," Boote told VICE News.
Nonetheless, it's important to go after sources of greenhouse gas emissions like the methane that comes from rice production, says Jesse Lasky, a postdoctoral scientist at Columbia University who has researched crops, genetics, and climate change.
"Especially if it's one where the goal of reducing emissions is coincident with increasing yield for a major crop," he told VICE News.
The genetically modified rice has less massive roots than the control rice does. Lasky questioned how the plants might deal with an unexpected drought.
"The fact that these have smaller roots begs the question of how they might respond to environmental stressors like that," he said.
Jansson from EMSL referred to the root question as "a very valid point." He explained that the genetically modified plants will be evaluated in China under a more substantive study, as well as undergo further research in his Washington laboratory.
Columbia University's Lasky said as genetics becomes a more mature science, researchers in the field might be able to make a greater contribution to solving problems like how to reduce agricultural emissions.
"Climate change is this huge challenge that we're facing as a society, and so we want to really bring everything we can to bear on it," he said.
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