title: Variation in the fumonisin biosynthetic gene cluster in fumonisin-producing and nonproducing black aspergilli.
abstract: The ability to produce fumonisin mycotoxins varies among members of the black aspergilli. Previously, analyses of selected genes in the fumonisin biosynthetic gene (fum) cluster in black aspergilli from California grapes indicated that fumonisin-nonproducing isolates of Aspergillus welwitschiae lack six fum genes, but nonproducing isolates of Aspergillus niger do not. In the current study, analyses of black aspergilli from grapes from the Mediterranean Basin indicate that the genomic context of the fum cluster is the same in isolates of A. niger and A. welwitschiae regardless of fumonisin-production ability and that full-length clusters occur in producing isolates of both species and nonproducing isolates of A. niger. In contrast, the cluster has undergone an eight-gene deletion in fumonisin-nonproducing isolates of A. welwitschiae. Phylogenetic analyses suggest each species consists of a mixed population of fumonisin-producing and nonproducing individuals, and that existence of both production phenotypes may provide a selective advantage to these species. Differences in gene content of fum cluster homologues and phylogenetic relationships of fum genes suggest that the mutation(s) responsible for the nonproduction phenotype differs, and therefore arose independently, in the two species. Partial fum cluster homologues were also identified in genome sequences of four other black Aspergillus species. Gene content of these partial clusters and phylogenetic relationships of fum sequences indicate that non-random partial deletion of the cluster has occurred multiple times among the species. This in turn suggests that an intact cluster and fumonisin production were once more widespread among black aspergilli.
authors.affiliation: Institute of Sciences of Food Production, CNR, via Amendola 122/0, 70126 Bari, Italy. Electronic address: antonella.susca@ispa.cnr.it.
authors.forename: Antonia
authors.initials: A
authors.lastname: Susca
authors.affiliation: US Department of Agriculture, Agriculture Research Service, National Center for Agricultural Utilization Research, 1815 North University Street, Peoria, IL 61604-3902, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Proctor
authors.affiliation: US Department of Agriculture, Agriculture Research Service, National Center for Agricultural Utilization Research, 1815 North University Street, Peoria, IL 61604-3902, USA.
authors.forename: Robert A E
authors.initials: RA
authors.lastname: Butchko
authors.affiliation: Institute of Sciences of Food Production, CNR, via Amendola 122/0, 70126 Bari, Italy.
authors.forename: Miriam
authors.initials: M
authors.lastname: Haidukowski
authors.affiliation: Institute of Sciences of Food Production, CNR, via Amendola 122/0, 70126 Bari, Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Stea
authors.affiliation: Institute of Sciences of Food Production, CNR, via Amendola 122/0, 70126 Bari, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Logrieco
authors.affiliation: Institute of Sciences of Food Production, CNR, via Amendola 122/0, 70126 Bari, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Moretti
mesh_terms: D001234:Aspergillus niger / Q000235:genetics* / Q000378:metabolism; D037341:Fumonisins / Q000378:metabolism*; D016681:Genome, Fungal; D005810:Multigene Family; D010802:Phylogeny; D027843:Vitis / Q000382:microbiology
chemical_list: D037341:Fumonisins
keywords: Biosynthetic gene cluster; Black aspergilli; Fumonisin; Gene cluster deletion; Grape