Study: Plant hormones act independently

LA JOLLA, Calif., Aug. 10 (UPI) -- U.S. plant biologists have determined each growth-regulating hormone in a plant acts largely independently.

For years, debate swirled around whether pathways activated by growth-regulating plant hormones converge on a central growth regulatory module. Now the scientists at the Salk Institute for Biological Studies are challenging that theory.

The Salk team found specific plant hormones often activate different factors rather than a common target.

"This result was completely unexpected because hormones with similar effects on plant growth seem to act on different gene sets," said the study's lead author Joanne Chory, a professor of plant biology and investigator with the Howard Hughes Medical Institute.

Plants rely on hormones to regulate every aspect of their biology. Growth, for example, is stimulated by multiple hormones and the fact several hormones stimulate plant growth suggested to some investigators that eventually they all switch on the same growth-promoting genes.

But Chory's team found otherwise. Co-lead authors Jennifer Nemhauser, now an assistant professor at the University of Washington, and Fangxin Hong, a biostatistician in Chory's lab, found each hormone activated largely its own repertoire of target genes.

The research appears in the journal Cell.