Structure and biological activity of maculansin A, a phytotoxin from the phytopathogenic fungus Leptosphaeria maculans

Maculansin A, a unique derivative of mannitol containing the unusual chromophore 2-isocyano-3-methyl-2-butenoyl, was isolated from potato dextrose cultures of L. maculans virulent on canola (Brassica napus). Surprisingly, maculansin A was more toxic to resistant plants (B. juncea L.) than to susceptible plants (canola).