Proteomic analysis of secreted protein induced by a component of prey in pitcher fluid of the carnivorous plant Nepenthes alata

► PR proteins have been identified in the pitcher fluid of N. alata. ► Three PR proteins including class III peroxidase (Prx) were newly identified. ► Prx was induced after the addition of chitin to the pitcher fluid. ► The proteins have two roles, digestion of prey and the antibacterial effect. ► The system for digesting prey has evolved from the defense system against pathogens.