Response to Wounding

Wounding of tomato plants by mechanical injury or chewing by insects releases a factor that triggers accumulation of two proteinase inhibitors-throughout the plant body. These are inhibitors of serine endopeptidase. Pectic oligomeric fragments derived from cell wall can also induce proteinase inhibitor i.e., they act as elicitors. In fact, cell wall fragments are thought to be generalised elicitors of plant defence responses including phytoalexin synthesis in different plants. The pattern of induction of proteinase inhibitor in these fragments in excised plant tissue is quite like that of mechanical injury.