Localized control of cell death is crucial for the resistance of plants to pathogens. Papain-like
cysteine proteases (PLCPs) regulate plant defence to drive cell death and protection against
biotrophic pathogens. In maize (Zea mays), PLCPs are crucial in the orchestration of
salicylic acid (SA)-dependent defence signalling. Despite this central role in immunity, it
remains unknown how PLCPs are activated, and which downstream signals they induce to
trigger plant immunity. Here, we discover an immune signalling peptide, Z. mays immune …