The identified gene that will help develop plants to fight climate change

Hidden underground networks of plant roots snake through the earth in search of nutrients and water, in the manner of a worm in search of food. However, the genetic and molecular mechanisms that determine the parts of soil roots explored remain largely unknown. Researchers at the Salk Institute have discovered a gene for determining whether the roots grow deep or shallow in the soil.

In addition, the results, published in Cell on July 11, 2019, researchers will also be able to develop plants that can help combat climate change as part of the Salk Plant Control Initiative. The initiative aims to grow plants with more robust and deeper roots, able to store larger amounts of carbon underground for longer to reduce CO2 emissions into the atmosphere. The Salk initiative will receive more than $ 35 million from more than 10 people and organizations through the Audacious project to continue this effort.

"We are extremely excited about this first discovery on the road to achieving the goals of the Harnessing Plants Initiative," said Associate Professor Wolfgang Busch, lead author of the paper and a member of Salk's Cellular and Molecular Plant Biology Lab, thus Laboratory of Biology. "Reducing CO2 levels in the atmosphere is one of the big challenges of our time, and it's personally very important for me to look for a solution."

In the new work, the researchers used the model plant thale cress (Arabidopsis thaliana) to identify genes and their variants that regulate the functioning of auxin, a hormone that plays a key role in controlling the root system architecture. Although the influence on almost all aspects of plant growth is known, it is not known what factors influenced its impact on the root system architecture.

"In order to better see root growth, I have developed and optimized a new method for studying root systems of plants in the soil," says lead author Takehiko Ogura, a postdoctoral fellow at Busch Lab. "The roots of A. thaliana are incredibly small, so they are not easily visible, but by cutting the plant in half, we could better observe and measure the distribution of roots in the soil. "

The team discovered that a gene, called EXOCYST70A3, directly regulates the root system architecture by controlling the auxin pathway without disrupting other pathways. To do this, EXOCYST70A3 affects the distribution of PIN4, a protein known to affect the transport of auxin. When the researchers modified the EXOCYST70A3 gene, they discovered that the orientation of the root system had changed and that more and more roots were growing deeper into the soil.

"Biological systems are incredibly complex, so it's hard to link the molecular mechanisms of plants to an environmental response," says Ogura. "By associating the influence of this gene on root behavior, we revealed an important step in adapting plants to changing environments through the auxin pathway."