title: Population structure and aflatoxin production by Aspergillus Sect. Flavi from maize in Nigeria and Ghana.
abstract: Aflatoxins are highly toxic carcinogens that contaminate crops worldwide. Previous studies conducted in Nigeria and Ghana found high concentrations of aflatoxins in pre- and post-harvest maize. However, little information is available on the population structure of Aspergillus Sect. Flavi in West Africa. We determined the incidence of Aspergillus Sect. Flavi and the level of aflatoxin contamination in 91 maize samples from farms and markets in Nigeria and Ghana. Aspergillus spp. were recovered from 61/91 maize samples and aflatoxins B1 and/or B2 occurred in 36/91 samples. Three samples from the farms also contained aflatoxin G1 and/or G2. Farm samples were more highly contaminated than were samples from the market, in terms of both the percentage of the samples contaminated and the level of mycotoxin contamination. One-hundred-and-thirty-five strains representative of the 1163 strains collected were identified by using a multilocus sequence analysis of portions of the genes encoding calmodulin, β-tubulin and actin, and evaluated for aflatoxin production. Of the 135 strains, there were 110 - Aspergillus flavus, 20 - Aspergillus tamarii, 2 - Aspergillus wentii, 2 - Aspergillus flavofurcatus, and 1 - Aspergillus parvisclerotigenus. Twenty-five of the A. flavus strains and the A. parvisclerotigenus strain were the only strains that produced aflatoxins. The higher contamination of the farm than the market samples suggests that the aflatoxin exposure of rural farmers is even higher than previously estimated based on reported contamination of market samples. The relative infrequency of the A. flavus SBG strains, producing small sclerotia and high levels of both aflatoxins (B and G), suggests that long-term chronic exposure to this mycotoxin are a much higher health risk in West Africa than is the acute toxicity due to very highly contaminated maize in east Africa.
authors.affiliation: Institute of Sciences of Food Production, CNR, via Amendola 122/O, 70126 Bari, Italy.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Perrone
authors.affiliation: Institute of Sciences of Food Production, CNR, via Amendola 122/O, 70126 Bari, Italy.
authors.forename: Miriam
authors.initials: M
authors.lastname: Haidukowski
authors.affiliation: Institute of Sciences of Food Production, CNR, via Amendola 122/O, 70126 Bari, Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Stea
authors.affiliation: Institute of Sciences of Food Production, CNR, via Amendola 122/O, 70126 Bari, Italy.
authors.forename: Filomena
authors.initials: F
authors.lastname: Epifani
authors.affiliation: International Institute of Tropical Agriculture (IITA), PMB 5320, Oyo Road, Ibadan, Nigeria.
authors.forename: Ranajit
authors.initials: R
authors.lastname: Bandyopadhyay
authors.affiliation: Department of Plant Pathology, 4024 Throckmorton Plant Science Center, Kansas State University, Manhattan, KS 66506-5502, USA.
authors.forename: John F
authors.initials: JF
authors.lastname: Leslie
authors.affiliation: Institute of Sciences of Food Production, CNR, via Amendola 122/O, 70126 Bari, Italy. Electronic address: antonio.logrieco@ispa.cnr.it.
authors.forename: Antonio
authors.initials: A
authors.lastname: Logrieco
mesh_terms: D000348:Aflatoxins / Q000032:analysis* / Q000378:metabolism; D001230:Aspergillus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D005506:Food Contamination / Q000032:analysis*; D005869:Ghana; D008969:Molecular Sequence Data; D009549:Nigeria; D010802:Phylogeny; D003313:Zea mays / Q000737:chemistry* / Q000382:microbiology*
chemical_list: D000348:Aflatoxins
keywords: Aflatoxins; Aspergillus flavofurcatus; Aspergillus flavus L-strain; Aspergillus parvisclerotigenus; Corn; Multilocus analysis; West Africa; Zea mays