A secreted peptide acts on BIN2-mediated phosphorylation of ARFs to potentiate auxin response during lateral root development

Auxin signalling controls events in plant development, but it is unclear how auxin sensitivity is regulated. Hwang and colleagues find that phosphorylation of AUXIN RESPONSE FACTORS (ARFs) by BRASSINOSTEROID-INSENSITIVE 2 (BIN2) suppresses their interaction with the repressors AUX/IAA to enhance the transcription of auxin target genes, which is essential for lateral root emergence.