title: Clustering of two genes putatively involved in cyanate detoxification evolved recently and independently in multiple fungal lineages.
abstract: Fungi that have the enzymes cyanase and carbonic anhydrase show a limited capacity to detoxify cyanate, a fungicide employed by both plants and humans. Here, we describe a novel two-gene cluster that comprises duplicated cyanase and carbonic anhydrase copies, which we name the CCA gene cluster, trace its evolution across Ascomycetes, and examine the evolutionary dynamics of its spread among lineages of the Fusarium oxysporum species complex (hereafter referred to as the FOSC), a cosmopolitan clade of purportedly clonal vascular wilt plant pathogens. Phylogenetic analysis of fungal cyanase and carbonic anhydrase genes reveals that the CCA gene cluster arose independently at least twice and is now present in three lineages, namely Cochliobolus lunatus, Oidiodendron maius, and the FOSC. Genome-wide surveys within the FOSC indicate that the CCA gene cluster varies in copy number across isolates, is always located on accessory chromosomes, and is absent in FOSC's closest relatives. Phylogenetic reconstruction of the CCA gene cluster in 163 FOSC strains from a wide variety of hosts suggests a recent history of rampant transfers between isolates. We hypothesize that the independent formation of the CCA gene cluster in different fungal lineages and its spread across FOSC strains may be associated with resistance to plant-produced cyanates or to use of cyanate fungicides in agriculture.
authors: Department of Biological Sciences, Vanderbilt University Present address: Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA.
authors: M Holly
authors: MH
authors: Elmore
authors: Department of Biological Sciences, Vanderbilt University.
authors: Kriston L
authors: KL
authors: McGary
authors: Department of Biological Sciences, Vanderbilt University.
authors: Jennifer H
authors: JH
authors: Wisecaver
authors: Department of Biological Sciences, Vanderbilt University Present address: Department of Plant Pathology, The Ohio State University, Columbus, OH.
authors: Jason C
authors: JC
authors: Slot
authors: Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University.
authors: David M
authors: DM
authors: Geiser
authors: Bacterial Foodborne Pathogens and Mycology Research Unit, National Center for Agricultural Utilization Research, US Department of Agriculture, Agricultural Research Service, Peoria, Illinois.
authors: Stacy
authors: S
authors: Sink
authors: Bacterial Foodborne Pathogens and Mycology Research Unit, National Center for Agricultural Utilization Research, US Department of Agriculture, Agricultural Research Service, Peoria, Illinois.
authors: Kerry
authors: K
authors: O'Donnell
authors: Department of Biological Sciences, Vanderbilt University antonis.rokas@vanderbilt.edu.
authors: Antonis
authors: A
authors: Rokas
mesh_terms: D001203:Ascomycota / Q000235:genetics; D019759:Carbon-Nitrogen Lyases / Q000235:genetics*; D002256:Carbonic Anhydrases / Q000235:genetics*; D003485:Cyanates / Q000378:metabolism; D019143:Evolution, Molecular; D005670:Fusarium / Q000145:classification / Q000235:genetics*; D020440:Gene Duplication; D022761:Gene Transfer, Horizontal; D005800:Genes, Fungal; D005810:Multigene Family; D010802:Phylogeny
chemical_list: D003485:Cyanates; D002256:Carbonic Anhydrases; C019953:cyanate hydrolase; D019759:Carbon-Nitrogen Lyases
keywords: Fusarium oxysporum; convergent evolution; fungicide resistance; gene duplication; horizontal gene transfer; metabolic gene cluster