The present invention is drawn to a method of controlling gene expression in
plants. Specifically, the method comprises obtaining a transgenic plant comprising
at least two receptor expression cassettes and at least one target expression cassette.
The first receptor expression cassette comprises a nucleotide sequence for a 5
regulatory region operably linked to a nucleotide sequence which encodes a first
receptor polypeptide, and a 3 termination region. The second receptor expression
cassette comprises a nucleotide sequence for a 5 regulatory region operably
linked to a nucleotide sequence which encodes a second receptor polypeptide, and
a 3 termination region. The target expression cassette comprises a nucleotide
sequence for a 5 regulatory region operably linked to a nucleotide sequence
which encodes a target polypeptide, and a 3 termination region, wherein
the 5 regulatory region of the target expression cassette is activated
by the first and second receptor polypeptides in the presence of one or more chemical
ligands which are complementary to the ligand binding domain of the receptor polypeptides,
whereby expression of the target polypeptide is accomplished. The method is useful
for controlling various traits of agronomic importance, such as plant fertility.