Host-Pathogen Interactions in the System Arachis Hypogaea-Cercospora Arachidicola

Abstract

With the aim of producing transgenic peanut plants, resistant to the early leafspot disease, the reaction of various peanut genotypes upon infection with the pathogen Cercospora arachidicola has been examined. Besides the production of stilbene-type phytoalexins, suspension-cultured cells of a susceptible genotype did not react typically when examined for responses to infection. Only slight differences were observed when cells derived from a hypersensitive genotype were examined. Submerged cultures of the pathogen, grown on peanut cell walls, produced various carbohydrase activities capable of degrading plant cell wall polysaccharides including β-glucans. The apoplastic fluid from infected plant tissue also contained increased carbohydrase activities which could degrade peanut cell walls but no significant difference was observed between susceptible and resistant genotypes.