Gibberellin receptor GID1 reduces DELLA protein repression without breaking it down in Arabidopsis

DELLA repression of gibberellin signaling is relieved through both proteolysis-dependent and -independent pathways in Arabidopsis thaliana.

• DELLA proteins serve as negative regulators of gibberellin responses, affecting processes like seed germination and stem elongation.
• GA promotes the degradation of DELLA proteins via the ubiquitin-proteasome pathway, which requires specific GA receptors and the SLEEPY1 F-box protein.
• sly1 mutants show higher levels of DELLA proteins but exhibit milder dwarfism and germination issues compared to other mutants that disrupt GA signaling.
• Overexpression of GID1 can reverse the dwarf and infertility traits in sly1 mutants without reducing DELLA protein levels.
• The interaction between GA-bound GID1 and DELLA proteins suggests a potential mechanism for GA signaling that does not rely on DELLA degradation.

Simplified