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United States Department of Agriculture

Agricultural Research Service

Title: Genetic Variation and Aflatoxin Production in Aspergillus Tamarii and A. Caelatus

item Peterson, Stephen
item Horn, Bruce
item Goto, Tetsuhisa - JPN MINISTRY AG FORESTRY

Submitted to: International Workshop on Penicillium and Aspergillus
Publication Type: Proceedings
Publication Acceptance Date: May 19, 1998
Publication Date: N/A

Interpretive Summary: Aflatoxins are naturally occurring carcinogens produced by the molds Aspergillus flavus, A. parasiticus and A. nomius. Large amounts of corn, peanuts, and other commodities are rendered unfit for use when contaminated with these molds and their aflatoxins. Recently, A. tamarii, another species was reported to make aflatoxin. We reexamined the isolates making aflatoxin and found that the strains had been misidentified. The strain making aflatoxin belongs in the species A. caelatus. This finding will affect import-export and commodity quality regulations by defining which mold species make aflatoxin and represent a potential threat to public health.

Technical Abstract: Recently, aflatoxin production has been reported in two strains of Aspergillus tamarii. This is the first verified report of aflatoxin production by this species, but A. tamarii is composed of distinct phenotypes, and a new species, A. caelatus, was named (Horn, 1997) for one of the phenotypic groups found in A. tamarii. We have analyzed molecular genetic data to test whether A. tamarii is composed of different genotypes that correspond to the named species and to determine whether the aflatoxigenic strains of A. tamarii are correctly identified. Phylogenetic analysis of these data show that A. tamarii and A. caelatus are distinct species. The aflatoxigenic strains of A. tamarii were found to be variants of A. caelatus rather than A. tamarii. A. tamarii can still be considered a non-aflatoxigenic species, but the aflatoxigenic A. caelatus strains could mistakenly be identified as A. tamarii under the Raper and Fennell (1965) species concepts.

Last Modified: 4/19/2015
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