Technical Abstract: Maize produces antimicrobial compounds (DIMBOA, MBOA, and BOA) implicated in disease resistance and insect feeding deterrence. Fusarium verticillioides, the most common fungal pathogen associated with maize, can biotransform these compounds into non-toxic metabolites. Genetic analyses identified two loci, FDB1 and FDB2, that are essential for this detoxification. Biotransformation of BOA is proposed to involve hydrolysis (Fdb1p) to produce 2-aminophenol, which is subsequently modified by; addition of a malonyl group (Fdb2p) to produce N-(2-hydroxyphenyl) malonamic acid. Suppression subtractive hybridization was used to identify genes up-regulated in response to BOA, and the proposed chemical pathway was supported by two of the identified genes. A putative amidase gene was cloned that genetically complemented a fdb1 mutation, while a putative N-malonyltransferase gene was cloned that complemented a fdb2 mutation. Such biotransformation may be an ecological fitness factor enhancing colonization of maize tissues and field residue.