Chemical Studies on Brown-spot Disease of Tobacco Plants

Tenuazonic acid has been isolated as a halo-inducing toxin from the culture filtrate of Alternaria longipes, a fungus causative of the tobacco brown-spot disease. Further, its occurrence in leaves of diseased plants was confirmed by a spectrometric method. The role of the acid in the host-parasite interaction was elucidated from the phytopathological standpoint.