Involved in the biosynthesis of the indole-derived phytoalexin camalexin. Catalyzes the conversion of indole-3-acetaldoxime to indole-3-acetonitrile. Required for resistance to A.brassicicola and B.cinerea. (E)-(indol-3-yl)acetaldehyde oxime = (indol-3-yl)acetonitrile + H2O By Pseudomonas syringae pv. tomato DC3000, Botrytis cinerea, flagellin, BTH and UV-C. Repressed by the transcription factors WRKY18 and WRKY40 upon infection with Golovinomyces orontii. Belongs to the cytochrome P450 family.