|Ito, Yoko - MAFF, JAPAN|
|Goto, Tetsuhisa - NFRI, MAFF, JAPAN|
Submitted to: Mycopathologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 10, 1999
Publication Date: N/A
Interpretive Summary: High levels of aflatoxin contamination in commodities renders them unfit for human or animal consumption. It is not known whether agricultural practices increase the prevalence of aflatoxin producing molds growing in the soil. We isolated and enumerated aflatoxin and non-aflatoxin producing molds from agricultural and non-agricultural soils in the tea growing regions of Japan. Repeated fertilization of tea-field soils acidifies them in relation to adjacent non-agricultural soils. We found higher numbers of aflatoxin producing fungi in the acidified agricultural soils than in the adjacent non-agricultural soils. Soil amendments to decrease acidity may help reduce the prevalence of aflatoxin producing fungi in agricultural soils.
Technical Abstract: Fungi in Aspergillus section Flavi include both aflatoxin producers and non-producers. Aspergillus caelatus is a recently described non- aflatoxigenic species in this section, which has some common characteristics with A. tamarii, such as yellowish brown color and double walled spores. In contrast to the morphological similarities, all of the A. caelatus isolates tested produced no cyclopiazonic acid whereas most isolates of A. tamarii produce this compound. There are six nucleotide differences that distinguish the DNA sequences of these two species in the regions of ITS1, ITS2, 5.8S rDNA, and 28S rDNA, and this is a consistent difference. Both species were isolated from acidified field soils, but A. tamarii isolates were more common than A. caelatus in highly acidic soils.