Thaxtomin A is a unique dioxopiperazine containing a 4-nitroindol-3-yl moiety isolated by scientists at Dow Agrisciences from Streptomyces scabies, the causative agent of common scab on new potatoes in 1989. Thaxtomin A is the predominant and most active member of the thaxtomin group of phytotoxins. Thaxtomin A acts as a herbicide via inhibition of cellulose biosynthesis. Atypical programmed cell death induced by thaxtomin A can be ameliorated by hydrogen peroxide. Thaxtomin A dysregulates K+ and Ca2+ fluxes in the roots of Arabidopsis.