Induction of Common Scab Symptoms in Aseptically Cultured Potato Tubers by the Vivotoxin, Thaxtomin

Inoculation of aseptically cultured minitubers with cell-free extracts from scab lesions of field-grown and cultured tubers infected with Streptomyces scabies reproduced symptoms typical of the common scab disease. Isolation and fractionation of the active components in tissue extracts by a combination of normal and reversed phase thin-layer chromatography yielded two active compounds. These have been designated thaxtomin A and thaxtomin B and characterized as unique 4-nitroindol-3-yl containing 2,5-dioxopiperazines. These phytotoxic principles satisfy all of the basic criteria of vivotoxins