has been characterized in plants (17-20), and no ligand has been defined for any plant GPCR. To identify previously unrecognized GPCR proteins in Arubidopsir, we started by searching the Arabidopuis genome and found a gene (GCR2, GenBank accession code At Ig52920) encoding a putative GPCR. Transmembrane

ediated signaling pathway plays a central role in vital processes such as vision, taste, and olfaction in animals (11). IlOwever. the higher plant Arubidopsir thulium has only one canonical Ga (GPAI) subunit, one G0 subunit, and two Gy subunits (12-16). The significance of these subunits in plant system