Plants need a variety of nutrients to grow, including nitrogen, phosphorus, and potassium. These nutrients are often in limited supply in soil, which can limit plant growth. However, the UC Davis team found that a protein called TOR (target of rapamycin) plays a key role in regulating plant growth in response to nutrient availability.
TOR is a kinase, an enzyme that adds a phosphate group to other proteins. The UC Davis team found that TOR phosphorylates a protein called S6K1, which in turn triggers a cascade of events that leads to increased cell growth and division. When nutrients are scarce, TOR activity is reduced, which leads to decreased S6K1 phosphorylation and slower growth.
"Our findings provide a molecular explanation for how plants integrate nutrient availability with growth," said study lead author Dr. Jian-Kang Zhu, a professor of plant biology at UC Davis. "This knowledge could be used to develop new strategies to improve crop yields by manipulating TOR signaling."
The researchers found that overexpression of TOR in plants resulted in increased growth and biomass production. Conversely, plants with reduced TOR activity grew more slowly and produced less biomass. These findings suggest that TOR is a key regulator of plant growth and could be a potential target for genetic engineering to improve crop yields.
The study also has implications for understanding how plants respond to environmental stresses, such as drought and high salinity. These stresses can reduce nutrient availability and lead to decreased plant growth. However, the researchers found that TOR signaling can help plants to tolerate these stresses and maintain growth.
"Our findings provide a new framework for understanding how plants regulate growth in response to nutrient availability and environmental stresses," said Zhu. "This knowledge could lead to new strategies to improve crop yields and make agriculture more sustainable."
The research was supported by the National Science Foundation and the U.S. Department of Agriculture.
