Common genotypes (RFLP) within a diverse collection of yellow-green aspergilli used to produce traditional Oriental fermented foods

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) 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 11 strains, GTAo-19 represented by 5 strains, GTAo-5 and GTAo-15 each represented by 4 strains, and GTAo-8, GTAo-17, and GTAo-24 each represented by 3 strains. Thirty-three single strain isolates of A. oryzae produced unique fingerprints. Our data offer 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; and (2) some Aspergillus genotypes employed in different fermentations and regions were derived from a common ancestral clonal population.

Taxonomy ofAspergillussectionFlaviand their production of aflatoxins, ochratoxins and other mycotoxins

“…Notes : NRRL 4894 was deposited by the Faculty of Engineering, Osaka University in the NRRL collection as A. oryzae var. fulvus Yamamoto ( Wicklow et al. 2002 ).…”

Diversity of Aspergillus oryzae genotypes (RFLP) isolated from traditional soy sauce production within Malaysia and Southeast Asia

“…No detectable afl atoxin was found in culture extracts of ten industrial strains of A. sojae (Matsushima et al 2001). Wicklow et al (2002) suggested that all strains of A. sojae used in the production of koji have originated from a common ancestral clonal population derived from A. parasiticus.…”

“…The isolation of A. sojae GTAo-9 (NRRL 32650;FTCC 5146) from the Kan Chong factory in Penang is of particular signifi cance in that it offers further evidence that A. sojae is of Chinese origin. Wicklow et al (2002) reported two strains classifi ed as A. sojae GTAo-9 NRRL 1988and NRRL 1989(N.B.I.R. 2016 isolated from soy sauce koji in Nanking, China, and received in 1947 from Mr. P.-S. King.…”

“…The mycelial mat was placed in Sarstedt tubes, frozen overnight, and lyophilized for 24 h. DNA from the harvested mycelial mat was isolated and purifi ed using the method of E. Raeder and P. Broda as modifi ed by McAlpin and Mannarelli (1995). Wicklow et al 2002) and a lambda standard. Strains producing similar banding patterns in different gels were reprobed on the same gel to verify fragment positions.…”

Aspergillus bombycis genotypes (RFLP) from silkworm cultivation

“…Aspergillus bombycis is also described with a colony texture being floccose and pale greenish-yellow in color, the absence of sclerotia, and smooth stipes (Peterson et al 2001). This common cultural appearance could suggest some degree of morphological convergence among isolates of Aspergillus section Flavi from diseased silkworms and the Aspergillus section Flavi cultures used as koji for traditional oriental food fermentations (Wicklow 1984;Wicklow et al 2002). At the same time, isolates of Aspergillus section Flavi from silkworm cultivation produce aflatoxins whereas domesticated koji molds do not (Wang and Hesseltine 1982).…”