Submitted to: Mycological Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/16/2000
Publication Date: N/A
Interpretive Summary: Recently, some unusual strains of Aspergillus tamarii were found that produce aflatoxin, a potent, naturally produced, cancer causing chemical. Prior to this report, A. tamarii was considered to be a non-aflatoxin producing species and has been used in the fermentation of an Asian food product, tamari sauce. We studied colony growth characteristics, toxin production profiles, and DNA sequence similarity to determine whether these atypical strains really belong in A. tamarii or whether they should be placed in a different species. While the visual differences are slight, our DNA sequence data show that these aflatoxin producing strains represent a different and new species that we have named Aspergillus pseudotamarii. Aspergillus tamarii may again be considered a non- aflatoxin producing species for regulatory and food production purposes.
Technical Abstract: The recent report of an aflatoxin producing isolate of Aspergillus tamarii prompted a taxonomic reexamination of aflatoxigenic and non-aflatoxigenic isolates identified as A. tamarii as well as the closely related A. caelatus. Representatives of each species, including atypical isolates, were compared morphologically, for mycotoxin production, and for divergence in ITS, 28S, Beta-tubulin, and calmodulin gene sequences. Because of genetic, morphological, and mycotoxin differences, the aflatoxin producing isolates of A. tamarii have been given species rank as Aspergillus pseudotamarii.