Induction of disease resistance in plants can be a better option in the management of alarming microbial plant diseases. Streptomyces albolongus isolate which proved to produce antifungal compounds exhibited antagonism against notorious plant pathogens in our past research. The present work focuses on the utility of S. albolongus metabolites in activating tomato plant defense system challenged by Pseudomonas syringae and Corynespora cassiicola. Metabolites extracted by ethyl acetate were found to contain a high amount of linolenic acid, azelaic acid, hexadecanoic acid and propyl ester of octadec-9-enoic acid as analyzed by Fourier-transform infrared spectroscopy and Gas chromatography–mass spectrometry techniques. Disease severity was significantly low in tomato plants that received metabolite application. Raised peroxidase and polyphenoloxidase enzyme activities were recorded in plants that received metabolite application compared to control plants. Gene expression studies indicated that parallel activation of pathogenesis related and Proteinase inhibitor (PinII) genes contributed for resistance against P. syringae. We report the possible role of C 9 and C 18 fatty acids in triggering salicylic acid and jasmonic acid pathways of tomato plants in response to P. syringae and C. cassiicola inoculation.