Herbivore and phytohormone induced defensive response in kale against cabbage butterfly, Pieris brassicae Linn

The constitutive and induced resistance were studied in two varieties (Khanyari and Kawdari) of kale, Brassica oleracea var. acephala in response to cabbage butterfly, Pieris brassicae infestation and exogenous application of jasmonic acid (JA) and salicylic acid (SA). Phenols, condensed tannins, flavonoids and proteins were measured at six days after JA (1 mM) and SA (1 mM) application and/or insect infestation. Plant damage and larval weights were also recorded. Khanyari variety showed highest amounts of phenols (208.23 mu g/g FW), condensed tannin (347.76 mu g/g FW), flavonoids (175.61 mu g/g FW) and proteins (0.71 mg/g FW) in plants pre-treated with JA and infested with insects. The PAL activity was high in response to JA application followed by insect infestation. Insects reared on Khanyari and Kawdari plants pre-treated with JA prior showed significantly reduced larval weights (97.88 and 102.46 mg, respectively). Damage was low in plants pre-treated with JA in Khanyari at 3, 6 and 9 days after treatment (10.52%, 8.52%, and 5.30%, respectively). Thus, JA can play an important role in plant defense in kale against P. brassicae.