DURHAM, N.C. -- Just as a hard-charging person sometimes needs a calming partner to be more effective, so it is with a pair of critical proteins that promote cell division and growth in the rapidly expanding root tip of plants.

One of the pair, a molecule called Scarecrow, physically restrains its highly influential counterpart from going farther than it should and doing more work than is needed.

As a result of this restraint, Scarecrow and its partner, called Short-root, manage to assemble a single ring of waterproofing that enables the plant to perform the critical function of controlling how much water and nutrient it takes in via the root.

"Knowing more about how plants developed this key ability to keep water out and let nutrients in is another step toward engineering plants that may be used to replace fossil fuels," said Duke biologist Philip Benfey. "It's also another step toward a better understanding of how humans work."

This emerging picture of the complex interplay between genes and proteins is the latest finding to come from Benfey's examination of the model mustard plant Arabidopsis thaliana.

"It's a simple model for us to get at some very complex relationships between genes and proteins and cells," said Benfey, the Paul Kramer Professor of Biology and director of Duke's new Center for Systems Biology in the Institute for Genome Sciences & Policy.

Benfey and Duke postdoctoral fellow Hongchang Cui published the findings in the April 20, 2007, issue of the journal Science. The research was supported by the National Institutes of Health.

The fast-growing root tip of Arabidopsis is literally a timeline of how generic, undifferentiated cells reach various specialized fates and begin doing specific tasks within the plant. It is also a perfectly symmetrical structure that can be easily sectioned, viewed and photographed.

There are 17 different cell types in the root tip, arising
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Contact: Karl Leif Bates
karl.bates@duke.edu
919-681-8054
Duke University
19-Apr-2007