The perception of the pathogen signal by the host specific receptors and its
transduction by various signaling pathways culminate in the synthesis and
synchronized accumulation of defensive molecules some of which play a structural role
while others exercise a direct antimicrobial function. Biochemical mechanisms include,
among others, the synthesis of peptides and antimicrobial proteins, hydrolytic enzymes
as well as the production of phytoalexins and secondary metabolites with high
antimicrobial potential. This chapter provides a synthesis of the remarkable progress
made in recent years in terms of understanding the mechanisms applied in the
molecular and physiological alterations that occur during the defense response of
plants.
Keywords: Defensins, Hypersensible response (HR), Protease inhibitors,
Phytoalexins, Pathogenesis-related proteins (PRs), Secondary metabolites.
