Scientists from the Howard Hughes Medical Institute have deciphered the signalling pathway for brassinosteroids, a class of plant hormones that regulates growth and development.

"Without them, plants are tiny dwarves, with reduced vasculature and roots, and are infertile. They also regulate senescence or aging. Since brassinosteroids mainly regulate cell expansion, though, they are one of the most important hormones that regulate stature."

By regulating the amount of brassinosteroids expressed in plants, plant stature can be manipulated, with practical applications ranging from perpetually short grasses, and controlling the heights of crops such that yield is maximized. An article discussing the findings is published in the May 4 issue of Nature: Downstream nuclear events in brassinosteroid signalling.

[Photo: The level of brassinosteroids regulates both the size and senescence of tobacco. With low levels, tobacco is dwarfed (some as small as 10 inches tall; see plant in front) and the leaves do not senesce, while at normal levels of brassinosteroids, tobacco stands almost 6 feet tall and the leaves turn yellow as they age (plant in back). Courtesy of Michael Neff and Joanne Chory]