ARS | Publication request: Genotypic Diversity of Aspergillus Parasiticus in An Illinois Corn Field

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 13, 1997
Publication Date: N/A

Technical Abstract: Aspergillus parasiticus Speare was isolated from direct platings of soil (Bloomfield sand) sampled from a corn field near Killbourne, Illinois. Fewer than five colony forming units of A. parasiticus were recorded from one-half gram quantities of soil that were added to Botran medium and incubated at 37.5 deg C. Sixty isolates, each one from a separately collected soil sample, were examined for ability to produce sclerotia, aflatoxins, and submitted to DNA fingerprinting. Pst I digests of total genomic DNA from each isolate were probed using the pAF28 repetitive sequence. Among 60 isolates analyzed, 45 distinct DNA fingerprint groups were identified (each group sharing less than 80% pAF28 band similarity). A. parasiticus genotype #8 represented 12% of the sample population. The 75% genotypic diversity of the A. parasiticus population was only marginally lower than the 84% genotypic diversity recorded earlier for a population of Aspergillus flavus isolates from the same soil samples. Sclerotia were produced by 75% of the A. parasiticus genotypes during dark incubation (25 deg C). All isolates of A. parasiticus produced aflatoxin B1 and G1, while only 42% of the A. flavus genotypes produced aflatoxins.