Key Plant Receptors Discovered

The Science

The phytohormone abscisic acid (ABA) plays important regulatory roles in physiological pathways for plant growth and development and enables adaptation to environmental stresses, yet the protein recognition mechanisms for this hormone have eluded plant biologists. Plants face a variety of environmental stresses, including drought, salinity, and cold. In the face of such stresses, the hormone ABA triggers adaptive physiological responses. ABA acts in seed dormancy, plant development, and drought tolerance. Crystallographic and small-angle X-ray scattering capabilities at the Advanced Light Source enabled researchers to determine the atomic resolution of the ABA receptor and identify conformational changes on the ABA binding site.

The crystallographic structure shows that PYR1 is a direct ABA receptor and sensor, signaling hormone binding within an internal cavity through conformational changes affecting the dimer interface and assembly. Furthermore, the mechanistic basis of ABA binding reported here provides a framework for future design of alternate ligands for the large ABA-binding cavity to enable chemical activation of abiotic stress resistance in plants.Elucidating the structural mechanisms mediating ABA receptor recognition and signaling is essential for understanding and manipulating abiotic stress resistance.

The Impact

These results were listed as one of the top 10 scientific breakthroughs of the year in 2009 by Science.

Principal Investigator

Elizabeth D. Getzoff


Nishimura, N., K. Hitomi, A. S. Arvai, R. P. Rambo, C. Hitomi, S. R. Cutler, J. I Schroeder, and E. D. Getzoff. 2009. “Structural Mechanism of Abscisic Acid Binding and Signaling by Dimeric PYR1,” Science 326, 1373–79. DOI:10.1126/science.118182.