Science has known about plant hormones since Charles Darwin experimented with plant shoots and showed that the shoots bend toward the light as long as their tips, which are secreting a growth hormone, aren't cut off.
But it is only recently that scientists have begun to put a molecular face on the biochemical systems that modulate the levels of plant hormones to defend the plant from herbivore or pathogen attack or to allow it to adjust to changes in temperature, precipitation or soil nutrients.
Now, a cross-Atlantic collaboration between scientists at Washington University in St. Louis, and the European Synchrotron Radiation Facility and the European Molecular Biology Laboratory, both in Grenoble, France, has revealed the workings of a switch that activates plant hormones, tags them for storage or marks them for destruction.
The research appeared online in the May 24 issue of Science Express and will be published in a forthcoming issue of Science.
"The enzymes are cellular stop/go switches that turn hormone responses on and off," says Joseph Jez, PhD, associate professor of biology in Arts & Sciences at WUSTL and senior author on the paper.
The research is relevant not just to design of herbicides some of which are synthetic plant hormones but also to the genetic modification of plants to suit more extreme growing conditions due to unchecked climate change.
What plant hormones do
Plants can seem pretty defenseless. After all, they can't run from the weed whacker or move to the shade when they're wilting, and they don't have teeth, claws, nervous systems, immune systems or most of the other protective equipment that comes standard with an animal chassis.
But they do make hormones. Or to be precise because hormones are often defined as chemicals secreted by glands and plants don't have glands they make chemicals that in very low concentrations dramatically alter their
|Contact: Diana Lutz|
Washington University in St. Louis