Aspartyl protease involved in a homeostatic feedback mechanism regulating systemic immunity. Has only mild or no influence on local defenses. Acts downstream of salicylic acid to suppress systemic immunity. Up-regulated locally and systematically during systemic acquired resistance (SAR) and locally by salicylic acid. The local induction is independent of EDS1 while the systemic induction is EDS1-dependent. Belongs to the peptidase A1 family.