The present invention provides polynucleotides encoding mutated PYR/PYL receptor polypeptides that are agonized by chemicals, such as bromoxynil, chloroxynil, ioxynil, coumatetralyl, dichlobenil, fenhexamid, benoxacor, and BTH, that do not agonize wild-type PYR/PYL receptor polypeptides, and expression cassettes and plants comprising the polynucleotides. Particular embodiments of the invention provide polynucleotides encoding mutated PYR/PYL receptor polypeptides having a mutation in the ligand-binding pocket of the PYR/PYL receptor polypeptide.