Liu Xigang Yue Yanling Li Bin Wu Wei-Hua 1712-6 The plant hormone abscisic acid (ABA) regulates many physiological and developmental processes in plants. The mechanism of ABA perception at the cell surface is not understood. Here, we report that a G protein-coupled receptor genetically and physically interacts with the G protein alpha subunit GPA1 to mediate all known ABA responses in Arabidopsis. Overexpressing this receptor results in an ABA-hypersensitive phenotype. This receptor binds ABA with high affinity at physiological concentration with expected kinetics and stereospecificity. The binding of ABA to the receptor leads to the dissociation of the receptor-GPA1 complex in yeast. Our results demonstrate that this G protein-coupled receptor is a plasma membrane ABA receptor. A G protein-coupled receptor is a plasma membrane receptor for the plant hormone abscisic acid. 315 Ma Ligeng 17347412 Nie Yanli Li Wei Liu Xigang et al. 2007 Mar. Science 315(5819):1712-6. 2007 Mar 5819