Jill Banfield (scientist at the University of California) & Jennifer Doudna (RNA Specialist, Berkeley) along with their team of co-authors have published a paper that takes a significant step towards resolving the thorny problem of how to study and alter the genomes of microbes living in complex real-world environments like the gut microbiome or soil.
Problem of Methane Emission:
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Rice production is estimated to account for 12% of total global methane emissions, owing to anaerobic decomposition during the production process, as rice is grown primarily in flooded fields known as rice paddies. It emits up to 34 million tonnes of methane per year, accounting for about 2% of total greenhouse-gas emissions. China and India account for half of that total.
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The complexity of microbial communities has been a significant impediment to the development of technologies that can prevent diseases and improve agriculture. It's an important step toward reducing methane.
Research Insights:
The research is part of the Innovative Genomics Institute (IGI), a consortium founded by Doudna to develop applications for CRISPR and other genetic engineering techniques in health, food production, and other fields as this technology brings with it the promise that practical challenges can be overcome at the molecular level.
Much of the IGI's climate work is centered on rice science, which is a major source of calories for more than half of the world's population. Aside from the primary issue of ensuring that people have enough, rice also poses a significant climate challenge. Flooded fields are used to grow the crop. This water deprives the soil of oxygen, allowing methane-producing microbes to thrive- resulting in Methane Emission.
Rice fields act as smokestacks for soil methane, and in order to reduce emissions, scientists must first understand the microbes. The problem has been that cultivating microbial communities and tinkering with them in a lab using traditional tools "could take years or might fail entirely," according to the IGI authors. Their new paper shows how using a Crispr-based system can "shorten this process to weeks."
Closing the rice methane spigot could necessitate a variety of changes, either to the plants themselves or to the microbial network into which the roots grow. Engineered solutions could range from introducing microbes that can consume methane in the absence of oxygen to completely eliminating specific organisms from the soil, similar to how antibiotics kill disease-causing bacteria.
Pamela Ronald is a professor at the University of California, Davis, who has spent her entire career studying rice and has written a book about the future of food. More than a decade ago, she and a colleague discovered the gene that was used to create flood-resistant rice, which is now grown by more than 6 million farmers in India and Bangladesh.
There are over 130,000 different types of rice. There may be overlooked evolutionary skills lurking in those genomes that scientists could graft into agricultural varieties for heat resistance, nutrition, or disease prevention. Ronald's lab is searching for changes that, when combined with Banfield's microbial communities, could result in lower-emission crops.
Growing more rice on the same acreage reduces emissions; every 1% increase in yield reduces methane emissions by about 1%. Reducing the frequency with which rice fields are flooded can reduce emissions by up to half. Farmers who can control water flow to fields quickly have discovered that alternating wet and dry periods during the growing season can significantly reduce emissions. Other promising techniques include re-planting paddy straw in the off-season and seeding fields with biochar, a type of charcoal, to encourage greater carbon storage in soil.
Timothy Searchinger, a senior research scholar at Princeton University's Center for Policy Research on Energy and the Environment, applauds progress toward a high-ambition, a high-reward genetic-engineering breakthrough in collaboration with proven real-world techniques.
