Localized Accumulation of Rishitin in the Potato-Tuber Tissue Infected by an Incompatible Race of Phytophthora infestans

Abstract

By using highly resistant potato tubers infected with an incompatible race of Phytophthora infestans, experiments were carried out to determine where, and when rishitin accumulates in the infected tissue. An analytical method for rishtin was developed by taking advantage of the red color formation by rishitin when mixed with conc. H₂SO₄. Most of the amount of rishitin seemed to be present in infected brown cells and adjacent cells.
With the materials used in these experiments, rishitin was first detected about 10hrs, after inoculation (about 7-8hrs. after infection). After that it increased linearly with time for about 12hrs. Rishitin reached its maximum concentration within 2 or 3 days after inoculation, and then decreased rapidly.