Role of Certain Elicitors on the Chemical Induction of Resistance in Tomato against the Leaf Caterpillar Spodoptera litura Fab.

Elicitors of chemical induction were used to manipulate the activities of several putative defense related proteins in the leaves of tomato, Lycopersicon esculentum Mill. The four presumptive defenses manipulated were protinase inhibitors, polyphenol oxidase, peroxidase and lipoxygenase. The elicitors used were jasmonic acid (JA), salicylic acid (SA) and PGPR Pseudomonas aeruginosa. These elicitors were tested against growth and development of Spodoptera litura Fab. In order to asses the relative roles of proteins in induced resistance against S. litura. When activities of proteinase inhibitors and/or polyphenol oxidase in leaf tissue were high, growth rates of S. litura were low and vise versa. In contrast, high activities of peroxidase and lipoxygenase have no effect on growth and development of S. litura. The association of high levels of proteinase inhibitors and polyphenol oxidase strongly implies these proteins as causal agent inducing resistance against S. litura.