TableEdit

Ueguchi-Tanaka, M, Ashikari, M, Nakajima, M, Itoh, H, Katoh, E, Kobayashi, M, Chow, TY, Hsing, YI, Kitano, H, Yamaguchi, I and Matsuoka, M (2005) GIBBERELLIN INSENSITIVE DWARF1 encodes a soluble receptor for gibberellin. Nature 437:693-8

Gibberellins (GAs) are phytohormones that are essential for many developmental processes in plants. It has been postulated that plants have both membrane-bound and soluble GA receptors; however, no GA receptors have yet been identified. Here we report the isolation and characterization of a new GA-insensitive dwarf mutant of rice, gid1. The GID1 gene encodes an unknown protein with similarity to the hormone-sensitive lipases, and we observed preferential localization of a GID1-green fluorescent protein (GFP) signal in nuclei. Recombinant glutathione S-transferase (GST)-GID1 had a high affinity only for biologically active GAs, whereas mutated GST-GID1 corresponding to three gid1 alleles had no GA-binding affinity. The dissociation constant for GA4 was estimated to be around 10(-7) M, enough to account for the GA dependency of shoot elongation. Moreover, GID1 bound to SLR1, a rice DELLA protein, in a GA-dependent manner in yeast cells. GID1 overexpression resulted in a GA-hypersensitive phenotype. Together, our results indicate that GID1 is a soluble receptor mediating GA signalling in rice.

PubMed Online version:10.1038/nature04028

Amino Acid Sequence; Binding, Competitive; Cloning, Molecular; Epistasis, Genetic; Genes, Plant/genetics; Gibberellins/metabolism; Gibberellins/pharmacology; Molecular Sequence Data; Mutation/genetics; Oryza sativa/drug effects; Oryza sativa/genetics; Oryza sativa/metabolism; Phenotype; Plant Proteins/chemistry; Plant Proteins/genetics; Plant Proteins/metabolism; Protein Binding; Solubility; Sterol Esterase/chemistry