The aim of this study was to check if plants could adapt better to a pathogen if immunized prior to the pathogen attack. In order to achieve this, Brassica juncea(Bj) were immunized using known immunizers when they were seven days old. The effects were studied by checking for an increase in total protein levels and plant defence molecules (PR) at various time periods in controlled conditions, using specific assays. The results suggest an increase in stress in treated plants. Compared to the control, the chemically treated plants gave high levels of peroxide and phenolic concentrations, 72 hours after treatment. In notable time the plant adapted to the stress, which was observed with the gradual decline in the levels of defence molecule. This is when the pathogen was introduced, and the control plant dried off due the fungus infection (Rhizoctonia solani) while treated plants lesions on the leaves. The largest lesion size was of JA and OA. SA gave the smallest lesion size. Hence, using SA for immunization may help the plant defend better against future pathogen attacks