Effect of Preliminary Administration of Pisatin to Pea Leaf Tissues on the Subsequent Infection by Erysiphe pisi DC.

Abstract

Pisatin was taken up by pea leaf cells when administrated through the epidermis-stripped mesophyll. The concentration, however, reduced with time elapsed, suggesting a metabolic degradation of pisatin. Pisatin thus administrated in early stage of infection prevented significantly the infection (formation of secondary hyphae) of Erysiphe pisi on pea leaves even at concentrations that had been proved non-inhibitory to this fungus. These results indicated that reassessment of phytoalexin as an infection inhibitor rather than antimicrobial substance is necessary for discussing it's role in the determination of host-parasite specificity and disease resistance.