VIEW ARTICLE

Suppression of Steroid Glycoalkaloid Accumulation as Related to Rishitin Accumulation in Potato Tubers. M. Shih, Department of Biochemistry and Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907; J. Kuc(2), and E. B. Williams(3). (2)(3)Department of Biochemistry and Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907. Phytopathology 63:821-826. Accepted for publication 5 January 1973. DOI: 10.1094/Phyto-63-821.

The accumulation of fungitoxic steroid glycoalkaloids in potato tuber slices is markedly suppressed when the cut surface is inoculated with either Phytophthora infestans or Helminthosporium carbonum (a pathogen of corn), or treated with a cell-free sonicate of compatible or incompatible races of P. infestans. Suppression is greater with an incompatible than with a compatible race of P. infestans. Marked suppression of steroid glycoalkaloid accumulation is associated with the accumulation of high levels of rishitin. Exogenous α-solanine has little influence on the accumulation of steroid glycoalkaloids or rishitin. Aging for 72 hr before inoculation or treatment with sonicates, reduced rishitin accumulation and this effect did not appear to be caused by the steroid glycoalkaloids accumulated during aging prior to treatment or inoculation.