Songwen Zhang

Abstract The plant defence hormone salicylic acid (SA) triggers systemic acquired resistance by signalling through its receptor, NON-EXPRESSOR OF PATHOGENESIS-RELATED GENE 1 (NPR1), leading to widespread transcriptional reprogramming1,2. However, the molecular mechanism by which NPR1 senses SA and activates transcription remains unresolved. Here we show that SA stabilizes the SA-binding domain (SBD) of NPR1 and allosterically promotes its interaction with MED15A, a subunit of the Mediator complex.