Researchers now believe that almost all plant genes are expressed only at a particular time of day, depending on the growth condition. And they use growth and movement to maximize their chance of survival in a competitive environment a plant leaf, for instance, will literally move if it becomes shaded by another plant.
In 1880, in one of his lesser-known works that was not focused on animal evolution, Darwin first described this phenomenon. He found that rather than growing at a steady rate, plants often grow in regular nightly spurts.
The findings in this study were made with the plant Arabidopsis, a small plant in the mustard family that is often used as a model for genetic research. A glowing enzyme, luciferase, was attached to the genes that were identified as responsible for rhythmic growth. And it would glow, on and off, as the genes began functioning to create the hormones responsible for growth in the dark of night.
The research program also learned that most of the genes involved in this process have a common DNA sequence, which they called the "HUD" element for "hormone up at dawn."
Further studies are needed to identify a protein that attaches to this HUD element and regulates its function. Identifying that regulator, the scientists said, could open the door to ways to control plant growth and yield.
|Contact: Todd Mockler|
Oregon State University