ABSTRACT
Disease resistance in many plant-fungal pathogen interactions has been suggested to be due to inducible production of antibiotic low molecular weight compounds, i.e., phytoalexins (Keen, 1981). The induction of phytoalexins in infected plants is presumed to be mediated by an initial recognition process between plants and pathogens which involves detection of certain unique molecules of pathogen origin, termed elicitors, by recognitional receptor-like molecules in plants, thereby setting off a cascade of biochemical events leading ultimately to phytoalexin accumulation (Yoshikawa, 1983; Yoshikawa and Masago, 1982). However, detailed mechanisms involved in each biochemical process leading to the phytoalexin production are poorly understood. The main subject of this chapter is the molecular basis of the elicitation of glyceollin, a phytoalexin (Yoshikawa et al., 1978a) produced by the expression of monogenic resistance in soybean (Glycine max) to incompatible races of Phytophthora megasperma f. sp. glycinea (Pmg).
