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Title: COMMON GENOTYPES (RFLP) WITHIN A DIVERSE COLLECTION OF YELLOW-GREEN ASPERGILLI USED TO PRODUCE TRADITIONAL ORIENTAL FERMENTED FOODS

Author
item Wicklow, Donald
item McAlpin, Cesaria
item Peterson, Stephen

Submitted to: Mycoscience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/22/2002
Publication Date: 6/1/2002
Citation: WICKLOW, D.T., MCALPIN, C.E., PETERSON, S.W. COMMON GENOTYPES (RFLP) WITHIN A DIVERSE COLLECTION OF YELLOW-GREEN ASPERGILLI USED TO PRODUCE TRADITIONAL ORIENTAL FERMENTED FOODS. MYCOSCIENCE. 2002. v. 43. p. 289-297.

Interpretive Summary: Aspergillus oryzae and Aspergillus sojae, used in the production of traditional Oriental fermented beverages or foods, are identified in a recent U.S. Patent as 'biocompetitive agents' for controlling aflatoxin in susceptible grains and oil seeds. DNA fingerprinting was performed on 81 cultures of A. oryzae and A sojae deposited with the ARS Culture Collection beginning in 1909. Identical DNA fingerprints were produced by multiple cultures of A. sojae and A. oryzae obtained from different food fermentations, locations, and years. Our research has shown that Aspergillus isolates producing identical DNA fingerprints are vegetatively compatible and capable of forming a common filamentous network. This information will enable scientists to combine cultures with unique physiological or biochemical adaptations to produce a superior 'biocompetitive' inoculum and determine the common ancestry of industrial starter molds used as in food fermentations and as sources of industrial enzymes.

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 (McAlpin and Mannarelli, 1995). 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, GTAo-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. No matches were produced between DNA fingerprints of these domesticated yellow-green aspergilli and the fingerprints in our data base for 'wild' strains of Aspergillus flavus or Aspergillus parasiticus from crop fields in Georgia, Illinois or Iowa. 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.