GID1

GID1 (Gibberellin Insensitive Dwarf1) is a plant protein that functions as a gibberellin receptor, playing a crucial role in plant growth and development. Gibberellins are plant hormones that regulate various aspects of plant physiology, including stem elongation, seed germination, and flowering time. GID1 proteins are found in higher plants and are essential components of the gibberellin signaling pathway.

The GID1 protein was first identified in rice through genetic studies of gibberellin-insensitive dwarf mutants. These mutants exhibited reduced plant height and other growth abnormalities due to their inability to properly respond to gibberellin hormones. The discovery of GID1 revealed the molecular mechanism by which plants perceive and respond to gibberellin signals.

Structurally, GID1 belongs to the α/β-hydrolase fold family and contains a ligand-binding pocket that specifically recognizes bioactive gibberellins. When gibberellin binds to GID1, it induces a conformational change in the protein that allows it to interact with DELLA proteins, which are negative regulators of gibberellin signaling. This interaction leads to the degradation of DELLA proteins through the ubiquitin-proteasome pathway, thereby releasing the brake on gibberellin-responsive genes and promoting plant growth.

GID1 has been found to have multiple isoforms in many plant species, suggesting functional diversification. In rice, three GID1 genes (GID1a, GID1b, and GID1c) have been identified, each with potentially distinct roles in different tissues or developmental stages. Similar multiplicity is observed in other crops and model plants like Arabidopsis.

Research on GID1 has significant implications for agriculture, as manipulating gibberellin signaling through GID1 can influence plant architecture, yield, and stress responses. The protein represents a key target for genetic improvement of crop plants and continues to be studied for its role in plant hormone biology.