Induction of Rishitin Formation and Its Accumulation in the Potat_??_-tuber Tissues by DBCP Treatment

Abstract

Rishitin (norsesquiterpene alcohol) was produced in browning tissue and its adjacent tissue in response to nematocide DBCP treatment. It was shown that rishitin was induced in each tuber tissue of the common variety (Solanum tuberosum) having r-gene and interspecific variety (S. tuberosum×S. demissum) containing the resistance gene R₁. A trace amount of rishitin was found in tuber tissue without periderm when treated by DBCP. Rishitin concentration was higher in tuber tissue incubated at 25°C after DBCP treatment than in those at 20°C or 30°C. Rishitin was detected 24 hr after DBCP treatment. Thereafter, its concentration reached maximum about 5 or 7 days after the treatment. But its concentration was lower than that in the tissue infected by an incompatible race of Phytophthora infestans.