Biotech Updates

New ABA Receptors Identified

May 8, 2009

Life is difficult, especially for plants. They have to endure environmental stresses such as drought, freezing and heat. Good thing they are equipped with an arsenal of genes that helps them face adverse environmental conditions. Plants use specialized signals, called stress hormones, to sense difficult times and adapt to stressful conditions to enhance survival. One particular hormone, abscisic acid (ABA), is produced by a plant in large amounts during times of stress, and particularly during conditions of drought. The exact molecular mechanism by which ABA helps plants tolerate drought remains poorly understood. The quest for the ABA receptor is highly controversial, involving retractions of scientific papers as well as the publication of papers of questionable significance.

An international team of researchers from U.S., Canada and Spain has recently identified novel ABA receptors. Using pyrabactin, a synthetic growth inhibitor that mimics ABA which the team identified through chemical genomics, the researchers pinpointed PYR/PYLs as ABA receptors functioning at the apex of a negative regulatory pathway. PYR/PYLs regulates the ABA signaling pathway by inhibiting the action of Type 2C protein phosphatases (PP2Cs), proteins that play linchpin role in the relay of ABA signals.

Sean Cutler, lead author of the paper published by Science, is aware of the prior questionable data in the ABA field. So he took the unusual step of sharing his data with key competitors and turning them into collaborators before publishing the results. In a press release, Natasha Raikhel, the director of the University of California's Center for Plant Cell Biology and a co-author of the paper said: "Several high-profile papers have tried to claim discovery of ABA receptors but their research could not stand the test of time… I believe this time, Dr. Cutler and his team have isolated a true ABA receptor."

View the press release at http://newsroom.ucr.edu/news_item.html?action=page&id=2077 The paper published by Science is available to subscribers at http://dx.doi.org/10.1126/science.1173041