In the diagram, solid lines indicate protein–protein interaction or post-translational modification, and dashed lines indicate transcriptional regulation. Red lines indicate new discoveries made in this study. In the BAP module, all three transcription factors, BR-regulated BZR1, auxin-regulated ARF6, and light/temperature-regulated PIF4, interact with each other and cooperatively regulate shared target genes and hypocotyl cell elongation. GA-regulated DELLA interacts with all BAP transcription factors and inhibits their DNA binding. Downstream of BAP module, the HLH/bHLH module, consisting of PRE1, IBH1/PAR1 and HBI1/PIF, modulates BAP activities through HLH–bHLH interactions. The BAP transcription factors positively regulate PRE1 in the HLH/bHLH module forming positive feedback loops. Development and pathogen signals are integrated into the central growth regulation network through PRE1/IBH1 and HBI1, respectively.