A team of scientists from Canada, Spain and the United States has identified a key gene that allows plants to defend themselves against environmental stresses like drought, freezing and heat.

"Plants have stress hormones that they produce naturally and that signal adverse conditions and help them adapt," says team member Peter McCourt, a professor of cell and systems biology at the University of Toronto. "If we can control these hormones we should be able to protect crops from adverse environmental conditions which is very important in this day and age of global climate change."

The research team, led by Sean Cutler of the University of California, Riverside, has identified the receptor of the key hormone in stress protection called abscisic acid (ABA). Under stress, plants increase their ABA levels, which help them survive a drought through a process not fully understood. The area of ABA receptors has been a highly controversial topic in the field of plant biology that has involved retractions of scientific papers as well as the publication of papers of questionable significance. A receptor is a protein molecule in a cell to which mobile signaling molecules may attach. Usually at the top of a signaling pathway, the receptor functions like a boss relaying orders to the team below that then executes particular decisions in the cell. "Scientists have been trying to solve the ABA receptor problem for more than 20 years, and claims for ABA receptors are not easily received by the scientific community," says Cutler.

This team used a new approach called chemical genomics to identifying a synthetic chemical, designated pyrabactin, which specifically activates an ABA receptor in the model laboratory plant Arabidopsis. With pyrabactin in hand it was now possible to directly identify the ABA receptor. "This approach not only found a gene that had been long sought by the plant science research community but also showed that chemical genomics can identify new chemicals like pyrabactin that may have profound impacts on the way we farm in both the developing and developed world," says McCourt.

The study results will appear April 30 in Science Express and in the May 22 issue of Science magazine. Lead author Sean Cutler is a former University of Toronto scientist who is now an assistant professor of plant cell biology in the Department of Botany and Plant Sciences at the University of California, Riverside. In addition to the University of Toronto and the University of California, Riverside, team members were from University of California, San Diego, Universidad Politecnica, Spain, the University of Ontario Institute of Technology, University of California, Santa Barbara; and the Medical College of Wisconsin.

Research was funded by the Canada Research Chair program, the Natural Sciences and Engineering Research Council. the National Science Foundation and the National Institutes of Health.

CONTACTS:
Peter McCourt
Cell and Systems Biology
University of Toronto
mccourt@csb.utoronto.ca
416-978-0523
416-978-0837
Kim Luke
Arts & Science Communications
University of Toronto
kim.luke@utoronto.ca
416-978-4352