Metabolism of analogs of the phytoalexin brassinin by plant pathogenic fungi

The metabolism of analogs of the cruciferous phytoalexin brassinin by the p hytopathogenic fungi Phoma lingam (Tode ex Fr.) "virulent" and "avirulent" groups (sexual stage Leptosphaeria maculans (Desm.) Ces. et de Not.) and Al ternaria brassicae (Berk.) Sacc. is reported. It was established that each pathogen detoxified methyl tryptamine dithiocarbamate, although yielding di fferent metabolic products. While the biotransformation by virulent P. ling am proceeded to yield methyl 3a-hydroxy-3,3a,8,8a-tetrahydropyrrolo[2,3-b]i ndol-1(2H)-yl carbodithioate and indole-3-acetic acid as final products, av irulent P. lingam yielded indole-3-carboxylic acid via N-b-acetyltryptamine , and A. brassicae yielded N-b-acetyltryptamine, as final products. Further more, to establish the importance of the dithiocarbamate group in antifunga l activity against P. lingam and A. brassicae, carbamates were compared wit h dithiocarbamates and it was established that carbamates were devoid of an tifungal activity. These products, contrary to methyl tryptamine dithiocarb amate, showed no inhibitory activity against either pathogen.