|Peterson, Stephen - Steve|
Submitted to: Aflatoxin Workshop
Publication Type: Abstract Only
Publication Acceptance Date: 10/25/2002
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: DNA fingerprinting was performed on 72 strains of Aspergillus oryzae and 9 strains of Aspergillus sojae isolated from chu (China) or koji (Japan), mold inoculum used in the production of traditional oriental fermented beverages or foods including soy sauce, miso, and sake. The cultures were deposited with the ARS Culture Collection (NRRL) in the years between 1909 and 2001. PstI digests of total genomic DNA from each isolate were probed using the pAF28 repetitive sequence. All strains of A. sojae that we examined produced an identical DNA fingerprint and belong to the same DNA fingerprint group (GTAo-9). Strains of A. oryzae were distributed among 41 DNA fingerprint groups, including GTAo-12 represented by eleven strains, GTA0-19 represented by five strains, GTAo-5, GTAo-15 each represented by four strains, and GTAo-8, GTAo-17, GTAo-24 each represented by three strains. Thirty-three single strain isolates of A. oryzae produced unique fingerprints. Aspergillus oryzae NRRL 30038 (= S-03) and A. sojae NRRL 30039 (= S-12) are identified in U.S. Patent No. 6,027,724 as useful fungal biocontrol agents for preventing aflatoxin contamination in agricultural commodities. The DNA fingerprint produced by A. sojae NRRL 30039 was identical to fingerprints of A. sojae isolates in GTAo-9. Aspergillus oryzae NRRL 30038 did not match fingerprints produced by any other strains of A. oryzae (< 80% band similarity). Our data offers evidence suggesting that (1) the successful domestication of A. parasiticus genotypes yielding A. sojae occurred far less frequently than among genotypes of A. flavus var. oryzae; (2) some Aspergillus genotypes employed in different fermentations and regions were derived from a common ancestral clonal population.