Inhibition of phytoalexin synthesis in arachidonic Acid-stressed potato tissue by inhibitors of lipoxygenase and cyanide-resistant respiration.

Arachidonic acid-stressed potato tuber discs synthesized the phytoalexin rishitin. This synthesis was inhibited by salicylhydroxamic acid (SHAM), and to a lesser extent by tetraethylthiuram disulfide (disulfiram). Disulfiram was less effective apparently because it was inactivated in the tuber discs. Disulfiram and SHAM both inhibited cyanide-resistant respiration of whole potato discs and lipoxygenase extracted from these discs. When low disulfiram concentrations were used, the lipoxygenase inhibition was quickly overcome, again because the disulfiram apparently was inactivated by oxidation.