Characterization of the Molecular Mechanism Underlying Gibberellin Perception Complex Formation in Rice

• Published in: The Plant cell Vol. 22; no. 8; pp. 2680 - 2696
• Main Authors: Hirano, Ko, Asano, Kenji, Tsuji, Hiroyuki, Kawamura, Mayuko, Mori, Hitoshi, Kitano, Hidemi, Ueguchi-Tanaka, Miyako, Matsuoka, Makoto
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Biologists 01.08.2010
• Subjects: Amino acids; Antibodies; Gene Expression Regulation, Plant; Genetic mutation; Gibberellins; Gibberellins - metabolism; Mutation; Oryza - genetics; Oryza - metabolism; Plant cells; Plant Growth Regulators - metabolism; Plant interaction; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Genetically Modified - genetics; Plants, Genetically Modified - metabolism; Polymerase chain reaction; Protein Interaction Domains and Motifs; Proteins; Rice; Yeasts
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.110.075549

The DELLA protein SLENDER RICE1 (SLR1) is a repressor of gibberellin (GA) signaling in rice (Oryza sativa), and most of the GA-associated responses are induced upon SLR1 degradation. It is assumed that interaction between GIBBERELLIN INSENSITIVE DWARF1 (GID1) and the N-terminal DELLA/TVHYNP motif of SLR1 triggers F-box protein GID2-mediated SLR1 degradation. We identified a semidominant dwarf mutant, Slr1-d4, which contains a mutation in the region encoding the C-terminal GRAS domain of SLR1 (SLR1G⁵⁷⁶V). The GA-dependent degradation of SLR1G⁵⁷⁶V was reduced in Slr1-d4, and compared with SLR1, SLR1G⁵⁷⁶V showed reduced interaction with GID1 and almost none with GID2 when tested in yeast cells. Surface plasmon resonance of GID1-SLR1 and GID1-SLR1G⁵⁷⁶V interactions revealed that the GRAS domain of SLR1 functions to stabilize the GID1-SLR1 interaction by reducing its dissociation rate and that the G576V substitution in SLR1 diminishes this stability. These results suggest that the stable interaction of GID1-SLR1 through the GRAS domain is essential for the recognition of SLR1 by GID2. We propose that when the DELLA/TVHYNP motif of SLR1 binds with GID1, it enables the GRAS domain of SLR1 to interact with GID1 and that the stable GID1-SLR1 complex is efficiently recognized by GID2.