Figure 3. Wound responses Wounds caused by herbivores induce a group of defences distinct from those that lead to systemic acquired resistance (see fig. 2). These defences can be induced by mechanically wounding the plant (a), but are greater if saliva is added to the cut (b). Such treatments promote the synthesis of jasmonic acid (JA), methyl jasmonate (MeJ) and ethene, which collectively activate defence related genes. The wounded leaf also exports long distance signals (which may include JA) to the rest of the plant. These signals induce JA, MeJ and ethene synthesis in undamaged tissues, leading systemic herbivore resistance.
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