Signal signature in induced defense of Arabidopsis upon pathogen and insect attack

Three plant signaling molecules play a dominant role in the regulation of defenses in a number of plant-attacker model systems: salicylic acid (SA), jasmonic acid (JA) and ethylene (ET). In this study, the roles of these signaling compounds were determined in the induced defense responses of Arabidopsis thaliana upon attack by a set of microbial pathogens and herbivorous insects. The production of SA, JA and ET was activated in different combinations depending on the attacker encountered resulting in a specific signal signature. Analysis of the expression of SA-, JA-, and ET- responsive marker genes showed that the signal signature nicely correlates with the expression of the marker genes in each plant-attacker interaction. We hypothesize that the specific signal signature is involved in the activation of an optimal mix of defenses to counteract the intruder