Altered gene helps plants absorb more carbon dioxide, produce more useful compounds
Every day, plants all over the world perform an invisible miracle. They extract carbon dioxide from the air and use sunlight to convert it into numerous chemicals that are essential to both plants and humans.
Some of these chemicals, known as aromatic compounds, are the starting material for a wealth of useful drugs, such as aspirin and morphine. Yet many of these chemicals come from fossil fuels because it is difficult to get plants to make enough of them to harvest economically. Others are essential human nutrients and can only be obtained through our food, as our bodies cannot make them.
In new work, scientists at the University of Wisconsin-Madison have found a way to reduce the brake on plants’ production of aromatic amino acids by changing or mutating one set of genes. The genetic change also caused the plants to absorb 30% more carbon dioxide than normal, without any adverse effect on the plants.
If scientists could add a trait like this to crops or plants that produce drugs, it could help them produce more chemicals naturally while reducing greenhouse gases in the atmosphere.
“We have long been interested in this aromatic amino acid pathway because it is one of the major plant pathways that converts carbon fixed by photosynthesis into drugs, food, fuels and materials,” said Hiroshi Maeda, a professor of botany at UW-Madison, who led the new investigation. “Now, for the first time, we’ve figured out how to control the main control knob that plants use to ramp up production from this pathway.”
Maeda and his team, led by postdoctoral researchers Ryo Yokoyama and Marcos Vinicius Viana de Oliveira, published their findings on June 8 in scientific progress†
Normally, plants strictly control the production of aromatic amino acids by building natural brakes into the process. When plants have made enough amino acids, the whole system comes to a halt.
The mutated plants Maeda’s team discovered using the model plant Arabidopsis have much less sensitive brakes thanks to mutations in a gene called DHS, which starts the production of aromatic amino acids. As a result, the plant does not know when to stop and continues to produce these compounds.
The scientists were surprised to find that the plants put photosynthesis into overdrive, bringing in significantly more carbon dioxide into the plant to fuel this new production boom.
“We think the increased photosynthesis does two things: the first is to provide additional energy to run this energetically expensive pathway. The second is to provide more carbon building blocks to make energetically dense aromatic chemicals,” Maeda says.
Some of these energy-rich compounds, such as lignin, find their way to the cell wall, where they form useful feed for biofuels.
Arabidopsis is just a small mustard plant. While it is a useful model in the lab, it yields nothing of value. Co-author de Oliveira has his sights set on testing similar mutations in crops — which take in huge amounts of carbon dioxide every year — or in plants that produce valuable aromatic chemicals.
“These brakes we identified are very similar in different plants. So extending this discovery to crops opens up a lot of possibilities, such as enriching our food with essential nutrients or improving bioenergy production, while capture more carbon dioxide from the atmosphere to slow global warming,” de Oliveira says.
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Ryo Yokoyama et al, Point mutations affecting the production of aromatic amino acids and CO. stimulate2 assimilation into plants, scientific progress (2022). DOI: 10.1126/sciaadv.abo3416
Quote: Altered gene helps plants absorb more carbon dioxide, produce more useful compounds (2022, June 8), retrieved June 9, 2022 from https://phys.org/news/2022-06-gene-absorb-carbon-dioxide- compounds.html
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