The study investigates the coordinated regulation of Arabidopsis thaliana development by light and gibberellins (GAs). DELLA proteins, which are GA-signalling repressors, play a crucial role in this process. In the absence of GA, DELLA proteins accumulate and interact with phytochrome-interacting factor 3 (PIF3), a transcription factor, preventing PIF3 from binding to target gene promoters and regulating gene expression. In the presence of GA, GID1 proteins (GA receptors) interact with DELLA proteins, triggering their ubiquitination and proteasomal degradation, thereby releasing PIF3 from DELLA protein inhibition. This study demonstrates that GA and light interact to regulate hypocotyl elongation, cotyledon opening, and light-responsive gene expression through the regulation of DELLA protein abundance. The interaction between DELLA proteins and PIF3 is mediated by physical interaction, and DELLA proteins antagonize PIF3 function by sequestering it, which affects gene expression and hypocotyl growth. The GA signal is relayed to DELLA protein abundance through the interaction between GID1 proteins and DELLA proteins, leading to their degradation. This coordinated regulation by light and GA ensures proper plant development.The study investigates the coordinated regulation of Arabidopsis thaliana development by light and gibberellins (GAs). DELLA proteins, which are GA-signalling repressors, play a crucial role in this process. In the absence of GA, DELLA proteins accumulate and interact with phytochrome-interacting factor 3 (PIF3), a transcription factor, preventing PIF3 from binding to target gene promoters and regulating gene expression. In the presence of GA, GID1 proteins (GA receptors) interact with DELLA proteins, triggering their ubiquitination and proteasomal degradation, thereby releasing PIF3 from DELLA protein inhibition. This study demonstrates that GA and light interact to regulate hypocotyl elongation, cotyledon opening, and light-responsive gene expression through the regulation of DELLA protein abundance. The interaction between DELLA proteins and PIF3 is mediated by physical interaction, and DELLA proteins antagonize PIF3 function by sequestering it, which affects gene expression and hypocotyl growth. The GA signal is relayed to DELLA protein abundance through the interaction between GID1 proteins and DELLA proteins, leading to their degradation. This coordinated regulation by light and GA ensures proper plant development.