Genes Involved in Brassinosteroid Hormone Action in Plants

Inventors: Joanne Chory and Zhiyong Wang
Potential Uses: Plant Biology, Agriculture, Horticulture
Methods of altering plant phenotypes including plant size by altering the genes encoding the Brassinozole Resistant 1 (BZR1) Polypeptide.

The invention includes the nucleic acid molecules encoding the Brassinazole Resistant 1 (BZR1) polypeptide and variants thereof, including the protein product of the dominant mutant bzr1-D, all of which are involved in the regulation of cell expansion in plants through effects on brassinosteroid response pathways. The BZ1 protein and bzr1-D protein appear to act downstream of the brassinosteroid receptor, so their action involves the brassinosteroid response pathway rather than the brassinosteroid biosynthetic pathway. The invention includes methods of modulating brassinosteroid-related responses, methods of identifying compounds involved in signaling pathways and methods of altering plant phenotypes by altering the genes encoding the BZR1 polypeptides. Plants with altered responses to brassinosteroids may be of particular economic interest to agriculture. For example, modification of brassinosteroid response pathways may produce larger plants with higher crop yields. Also, these response pathways may be modified in specific tissues or at specific developmental stages, to increase desirable qualities in agricultural products. It may be possible to produce crops with increased fruit size by linking fruit-specific promoters to genes with modified brassinosteroid responses.