ST. GEORGE — A team of researchers has identified a gene that helps plants grow longer roots. The potential benefits of such a discovery range from increasing carbon absorption and drought tolerance in the plants to reducing flooding risks and creating healthier soil.
The study, performed by plant biologists at the Salk Institute, discovered the gene that determines a plant’s root length, allowing scientists to use this information to genetically engineer plants with longer roots. The extended roots have the ability to store more carbon underground.
During the process of photosynthesis, plants absorb carbon dioxide and release oxygen into the air. The carbon absorbed into the plant is then deposited into the soil when they die or secreted into the ground through plant roots, which is beneficial to the soil.
However, some of the carbon that is deposited closer to the ground surface – especially in plants with shallower root systems – is released back into the atmosphere. Plant roots are naturally degraded by bacteria and other organisms in the soil. This degradation occurs slower and less frequently deeper in the ground.
Associate professor Wolfgang Busch, who is a member of Salk’s Plant Molecular and Cellular Biology Laboratory and senior author on the study, said plants with longer roots experience less degradation near the surface of the earth, so less carbon is released into the atmosphere and more carbon is be stored underground for a longer period of time.
“This is something that will counteract the increased carbon dioxide levels in the atmosphere because plants use photosynthesis to fix this carbon dioxide,” Busch said.
Professor Douglas Kell from the University of Manchester was the first to identify the environmental benefits of breeding crops with longer roots in a 2011 study.
The global amount of carbon dioxide in the atmosphere is now 410.34 parts per million, according to the National Oceanic and Atmospheric Association. Plants currently absorb around 25% of carbon that is being released into the air through the burning of fossil fuels.
Kell calculated that if all current crop lands could be replaced with plants engineered to have roots that are about 3 feet longer than they currently are, they could potentially double the amount of carbon plants remove from the air.
While the need had already been identified, the scientists at the Salk Institute aimed to find out how to make plants grow longer roots. They determined that a gene, identified as EXOCYST70A3, has the function of telling plants to grow toward the center of the earth. The gene also helps them get back on track when their roots aren’t aimed toward the earth’s center.
“The original study is really rooted in a fundamental science question,” Busch said. “And that is, which genes and which genetic and molecular mechanisms actually determine how roots grow and how they basically grow in a certain direction.”
With this information, the researchers can use genetic engineering or plant breeding to actually grow crops with longer root systems, providing a number of environmental benefits.
In addition to reducing the amount of carbon in the atmosphere, greater levels of carbon in the ground can increase soil health and help farmers produce better crop yields. Additionally, it increases the soil’s water holding capacity, which simultaneously reduces the risk of flooding and helps plants fight drought.
While the researchers have had success in editing plant genes to grow longer roots in a laboratory setting, they are currently in the process of researching and using field testing on crop plants.
The team’s efforts are being funded by The Audacious Project, in which 10 individuals and organizations have donated $35 million to go toward their research.
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