Pretreatment of parsley suspension cultures with salicylic acid enhances spontaneous and elicited production of H2O2. Leon et al. Hydrogen peroxide stimulates salicylic acid biosynthesis in tobacco. Production of salicylic acid precursors is a main function of phenylalanine-ammonia lyase in the resistance of Arabidopsis to Peronospora parasitica . Naylor et al.
Salicylic acid can induce resistance to plant virus movement.
Genetically engineered broad-spectrum resistance in tomato.