Cell linesthat may be used in the cell culture assay include any cells, including animal, human or plant cells, that are engineered (as described in Section 5) to express the plant GluR. Glutamate receptor gene products encoding plant iGluR, mGluR, glutamate-likereceptors, or any other glutamate receptor expressed in plants, as described in Section 5.1. may be expressed in cells for use in cell cu