Elicitor of plant defense. Induces the production of plant defensin (PDF1.2) and of H(2)O(2). Promotes resistance to the root fungal pathogen P.irregulare. Interacts with its receptor PEPR1. By wounding, methyl jasmonate (MeJA), ethylene. The expression of the peptide PEP1 precursor is induced by the mature peptide PEP1. Belongs to the brassicaceae elicitor peptide family.