Closely related receptor complexes differ in their ABA selectivity and sensitivity.

The recent discovery of a variety of receptors has led to new models for hormone perception in plants. In the case of the hormone abscisic acid (ABA), which regulates plant responses to abiotic stress, perception seems to occur both at the plasma membrane and in the cytosol. The cytosolic receptors for ABA have recently been identified as complexes between protein phosphatases 2C (PP2C) and regulatory components (RCAR/PYR/PYL) that bind ABA.