Submitted to: Mycological Society of America
Publication Type: Abstract only
Publication Acceptance Date: 6/16/2008
Publication Date: 8/9/2008
Citation: Glenn, A.E., Bacon, C.W. 2008. Fusarium verticillioides gene clusters associated with biotransformation of maize allelopathic compounds. Mycological Society of America. Aug. 9-13,2008. State College, PA. Interpretive Summary: Abstract - no summary required.
Technical Abstract: Maize produces the benzoxazinones DIMBOA and DIBOA, which naturally transform into the more stable benzoxazolinones MBOA and BOA, respectively. These weed-suppressive allelopathic compounds are also implicated in resistance to microbial diseases and insect feeding. Fusarium verticillioides is able to detoxify MBOA and BOA. The biotransformation pathway involves hydrolysis of BOA (encoded by the FDB1 locus) to produce 2-aminophenol, which is acylated (encoded by the FDB2 locus) to produce N-(2-hydroxyphenyl)malonamic acid. Growth is inhibited on BOA-amended medium if either locus is mutated. Using suppression subtractive hybridization to identify genes up-regulated in response to BOA, two gene clusters were identified that functionally correspond to the FDB1 and FDB2 loci. Of nine genes at the FDB1 locus, three were found to be necessary for biotransformation. The FDB2 locus consists of 13 genes, including one encoding a putative N-acetyltransferase (NAT). The subcloned NAT gene complemented an fdb2 mutation, and deletion of the gene eliminated the ability of F. verticillioides to metabolize BOA. The other 12 genes at the FDB2 locus were not essential for biotransformation. This work provides genetic evidence for the biochemistry of benzoxazolinone biotransformation, a metabolic process that may enhance the ecological fitness of F. verticillioides in the maize field environment.