Its mode of action does not depend on direct killing or inhibition of the invading pathogen, but rather on increasing physical or chemical barrier of the host plant.[1] Like the Systemic Acquired Resistance (SAR) a plant can develop defenses against an invader such as a pathogen or parasite if an infection takes place. In contrast to SAR which is triggered by the accumulation of salicylic acid, ISR instead relies on signal transduction pathways activated by jasmonate and ethylene.[2]