title: Two Horizontally Transferred Xenobiotic Resistance Gene Clusters Associated with Detoxification of Benzoxazolinones by Fusarium Species.
abstract: Microbes encounter a broad spectrum of antimicrobial compounds in their environments and often possess metabolic strategies to detoxify such xenobiotics. We have previously shown that Fusarium verticillioides, a fungal pathogen of maize known for its production of fumonisin mycotoxins, possesses two unlinked loci, FDB1 and FDB2, necessary for detoxification of antimicrobial compounds produced by maize, including the γ-lactam 2-benzoxazolinone (BOA). In support of these earlier studies, microarray analysis of F. verticillioides exposed to BOA identified the induction of multiple genes at FDB1 and FDB2, indicating the loci consist of gene clusters. One of the FDB1 cluster genes encoded a protein having domain homology to the metallo-β-lactamase (MBL) superfamily. Deletion of this gene (MBL1) rendered F. verticillioides incapable of metabolizing BOA and thus unable to grow on BOA-amended media. Deletion of other FDB1 cluster genes, in particular AMD1 and DLH1, did not affect BOA degradation. Phylogenetic analyses and topology testing of the FDB1 and FDB2 cluster genes suggested two horizontal transfer events among fungi, one being transfer of FDB1 from Fusarium to Colletotrichum, and the second being transfer of the FDB2 cluster from Fusarium to Aspergillus. Together, the results suggest that plant-derived xenobiotics have exerted evolutionary pressure on these fungi, leading to horizontal transfer of genes that enhance fitness or virulence.
authors.affiliation: USDA, ARS, Richard B. Russell Research Center, Toxicology & Mycotoxin Research Unit, Athens, Georgia, United States of America.
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Glenn
authors.affiliation: USDA, ARS, Richard B. Russell Research Center, Toxicology & Mycotoxin Research Unit, Athens, Georgia, United States of America.
authors.forename: C Britton
authors.initials: CB
authors.lastname: Davis
authors.affiliation: University of Georgia, Department of Plant Pathology, Athens, Georgia, United States of America.
authors.forename: Minglu
authors.initials: M
authors.lastname: Gao
authors.affiliation: USDA, ARS, Richard B. Russell Research Center, Toxicology & Mycotoxin Research Unit, Athens, Georgia, United States of America.
authors.forename: Scott E
authors.initials: SE
authors.lastname: Gold
authors.affiliation: USDA, ARS, Richard B. Russell Research Center, Toxicology & Mycotoxin Research Unit, Athens, Georgia, United States of America.
authors.forename: Trevor R
authors.initials: TR
authors.lastname: Mitchell
authors.affiliation: USDA, ARS, National Center for Agricultural Utilization Research, Mycotoxin Prevention and Applied Microbiology Research Unit, Peoria, Illinois, United States of America.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Proctor
authors.affiliation: Colorado State University, Bioagricultural Sciences & Pest Management, Fort Collins, Colorado, United States of America.
authors.forename: Jane E
authors.initials: JE
authors.lastname: Stewart
authors.affiliation: USDA, ARS, Richard B. Russell Research Center, Toxicology & Mycotoxin Research Unit, Athens, Georgia, United States of America.
authors.forename: Maurice E
authors.initials: ME
authors.lastname: Snook
mesh_terms: D001583:Benzoxazoles / Q000494:pharmacology; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005670:Fusarium / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D005810:Multigene Family / Q000235:genetics*; D015262:Xenobiotics / Q000494:pharmacology*
chemical_list: D001583:Benzoxazoles; D005656:Fungal Proteins; D015262:Xenobiotics; C017057:benzoxazolone