Large underground networks of roots forage the earth for nutrients and water. Although we have been familiar with this process for a long time, the precise mechanisms which govern how it happens have remained largely unknown. Researchers at the Salk Institute however, have begun to unravel this mystery, having just discovered a gene that determines how deep or shallow roots grow in soil.
In their work, they focused on studying gene variants present in thale cress (Arabidopsis thaliana) used to regulate auxin, a hormone responsible for much of root system architecture. Although known to influence every aspect of plant growth, its effects on root system architecture were mostly unknown.
During the research, as the roots of the plants were very small, and thus hardly visible, the researchers sliced them in half to better observe, measure and analyze them. In doing so, they found that one gene, EXOCYST70A3, directly regulates root system architecture by controlling auxin pathways without interfering with other processes.
They found that the gene does this by influencing the distribution of PIN4, a protein known to affect auxin transport. They also found that making alterations to the EXOCYST70A3 gene caused the root system to change orientation and for roots to grow deeper into the soil.
One of the benefits of this finding is that researchers are now closer to understanding how to grow plants with deeper, and more robust root systems that are capable of storing more carbon underground, thus reducing the overall CO2 in the atmosphere. Another benefit of this research is that it may be able to help scientists understand how plants adapt to seasonal variances in rainfall, and thus how to adapt plants to changing climates.
One of the researchers, Associate Professor Wolfgang Busch said, “We hope to use this knowledge of the auxin pathway as a way to uncover more components that are related to these genes and their effect on root system architecture...This will help us create better, more adaptable crop plants, such as soybean and corn, that farmers can grow to produce more food for a growing world population."