Angiosperm Flora of India

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

Publication Type:Journal Article
Year of Publication:2010
Authors:Hirano, K, Asano, K, Tsuji, H, Kawamura, M, Mori, H, Kitano, H, Ueguchi-Tanaka, M, Matsuoka, M
Journal:The Plant Cell
Date Published:2010
ISBN Number:10404651
Keywords:Oryza, Oryza sativa

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, Sir1-d4, which contains a mutation in the region encoding the C-terminal GRAS domain of SLR1 (SLR1 G576V ). The GA-dependent degradation of SLR1 G576V was reduced in Slr1-d4, and compared with SLR1, SLR1 G576V showed reduced interaction with GID1 and almost none with GID2 when tested in yeast cells. Surface plasmon resonance of GID1-SLR1 and GID1-SLR1 G576V 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.

Short Title:The Plant Cell
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