Non-Aflatoxigenicity of Commercial Aspergillus oryzae Strains Due to Genetic Defects Compared to Aflatoxigenic Aspergillus flavus
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Aspergillus oryzae is generally recognized as safe, but it is closely related to A. flavus in morphology and genetic characteristics. In this study, we tested the aflatoxigenicity and genetic analysis of nine commercial A. oryzae strains that were used in Korean soybean fermented products. Cultural and HPLC analyses showed that none of the commercial strains produced detectable amount of aflatoxins. According to the molecular analysis of 17 genes in the aflatoxin (AF) biosynthetic pathway, the commercial strains could be classified into three groups. The group I strains contained all the 17 AF biosynthetic genes tested in this study; the group II strains deleted nine AF biosynthetic genes and possessed eight genes, including aflG, aflI, aflK, aflL, aflM, aflO, aflP, and aflQ; the group III strains only had six AF biosynthetic genes, including aflG, aflI, aflK, aflO, aflP, and aflQ. With the reverse transcription polymerase chain reaction, the group I A. oryzae strains showed no expression of aflG, aflQ and/or aflM genes, which resulted in the lack of AF-producing ability. Group II and group III strains could not produce AF owing to the deletion of more than half of the AF biosynthetic genes. In addition, the sequence data of polyketide synthase A (pksA) of group I strains of A. oryzae showed that there were three point mutations (two silent mutations and one missense mutation) compared with aflatoxigenic A. flavus used as the positive control in this study.
Abstract
Aspergillus oryzae is generally recognized as safe, but it is closely related to A. flavus in morphology and genetic characteristics. In this study, we tested the aflatoxigenicity and genetic analysis of nine commercial A. oryzae strains that were used in Korean soybean fermented products. Cultural and HPLC analyses showed that none of the commercial strains produced detectable amount of aflatoxins. According to the molecular analysis of 17 genes in the aflatoxin (AF) biosynthetic pathway, the commercial strains could be classified into three groups. The group I strains contained all the 17 AF biosynthetic genes tested in this study; the group II strains deleted nine AF biosynthetic genes and possessed eight genes, including aflG, aflI, aflK, aflL, aflM, aflO, aflP, and aflQ; the group III strains only had six AF biosynthetic genes, including aflG, aflI, aflK, aflO, aflP, and aflQ. With the reverse transcription polymerase chain reaction, the group I A. oryzae strains showed no expression of aflG, aflQ and/or aflM genes, which resulted in the lack of AF-producing ability. Group II and group III strains could not produce AF owing to the deletion of more than half of the AF biosynthetic genes. In addition, the sequence data of polyketide synthase A (pksA) of group I strains of A. oryzae showed that there were three point mutations (two silent mutations and one missense mutation) compared with aflatoxigenic A. flavus used as the positive control in this study.
참고문헌 (28)
- An LH, "Quantitative realtime RT-PCR for determination of vitellogenin mRNA in soiuy mullet (Mugil soiuy)", Anal. Bioanal. Chem, 386, pp.1995~2001 (2006)
- Bennett JW, "Mycotoxins", Clin. Microbiol. Rev, 16, pp.497~516 (2003)
- Chang PK, "The Aspergillus parasiticus protein AFLJ interacts with the aflatoxin pathway-specific regulator AFLR", Mol. Genet. Genomics, 268, pp.711~719 (2003)
- Chang PK, "Identification of genetic defects in the atoxigenic biocontrol strain Aspergillus flavus K49 reveals the presence of a competitive recombinant group in field populations", Int. J. Food Microbiol, 154, pp.192~196 (2012)
- Chang PK, "What does genetic diversity of Aspergillus flavus tell us about Aspergillus oryzae?", Int. J. Food Microbiol, 138, pp.189~199 (2010)
- Chang PK, "Effects of laeA deletion on Aspergillus flavus conidial development and hydrophobicity may contribute to loss of aflatoxin production", Fungal Biol, 116, pp.298~307 (2012)
- Das MK, "Use of pyrosequencing to quantify incidence of a specific Aspergillus flavus strain within complex fungal communities associated with commercial cotton crops", Phytopathology, 98, pp.282~288 (2008)
- Dorner JW., "Biological control of aflatoxin contamination of crops", J. Toxicol. Toxin Rev, 23, pp.425~450 (2004)
- Ehrlich KC, "An isolate of Aspergillus flavus used to reduce aflatoxin contamination in cottonseed has a defective polyketide synthase gene", Appl. Microbiol. Biotechnol, 65, pp.473~478 (2004)
- Yu Jung Jung, "Isolation and Identification of Fungi from a Meju Contaminated with Aflatoxins", Journal of Microbiology and Biotechnology, 22(12), pp.1740~1748 (2012), 한국미생물·생명공학회[DOI]
- Kiyota T, "Aflatoxin non-productivity of Aspergillus oryzae caused by loss of function in the aflJ gene product", J. Biosci. Bioeng, 111, pp.512~517 (2011)
- Klich MA, "DNA restriction enzyme fragment polymorphism as a tool for rapid differentiation of Aspergillus flavus from Aspergillus oryzae", Exp. Mycol, 11, pp.170~175 (1987)
- Klich MA, "Hybridization of genes involved in aflatoxin biosynthesis to DNA of aflatoxigenic and nonaflatoxigenic aspergilli", Appl. Microbiol. Biotechnol, 44, pp.439~443 (1995)
- Kumeda Y, "Heteroduplex panel analysis, a novel method for genetic identification of Aspergillus section Flavi strains", Appl. Environ. Microbiol, 67, pp.4084~4090 (2001)
- Kusumoto K, "Directed deletions in the aflatoxin biosynthesis gene homolog cluster of Aspergillus oryzae", Curr. Genet, 37, pp.104~111 (2000)
- Kusumoto KI, "Transcript of a homolog of aflR, a regulatory gene for aflatoxin synthesis in Aspergillus parasiticus, was not detected in Aspergillus oryzae strains", FEMS Microbiol. Lett, 169, pp.303~307 (1998)
- Lee CZ, "Comparison of the aflR gene sequences of strains in Aspergillus section Flavi", Microbiology, 152, pp.161~170 (2006)
- Meyers DM, "Characterization of aflJ, a gene required for conversion of pathway intermediates to aflatoxin", Appl. Environ. Microbiol, 64, pp.3713~3717 (1998)
- Mishra HN, "A review on biological control and metabolism of aflatoxin", Crit. Rev. Food Sci. Nutr, 43, pp.245~264 (2003)
- Montiel D, "Genetic differentiation of the Aspergillus section Flavi complex using AFLP fingerprints", Mycol. Res, 107, pp.1427~1434 (2003)
- Payne GA, "Whole genome comparison of Aspergillus flavus and A. oryzae", Med. Mycol, 44, pp.9~11 (2006)
- Ramirez-Camejo LA, "Phylogeography of the cosmopolitan fungus Aspergillus flavus: is everything everywhere?", Fungal Biol, 116, pp.452~463 (2012)
- Scheidegger KA, "Unlocking the secrets behind secondary metabolism: a review of Aspergillus flavus from pathogenicity to functional genomics", J. Toxicol. Toxin Rev, 22, pp.423~459 (2003)
- Scherm B, "Detection of transcripts of the aflatoxin genes aflD, af1O, and aflP by reverse transcription-polymerase chain reaction allows differentiation of aflatoxin-producing and non-producing isolates of Aspergillus flavus and Aspergillus parasiticus", Int. J. Food Microbiol, 98, pp.201~210 (2005)
- Shapira R, "Detection of aflatoxigenic molds in grains by PCR", Appl. Environ. Microbiol, 62, pp.3270~3273 (1996)
- Tominaga M, "Molecular analysis of an inactive aflatoxin biosynthesis gene cluster in Aspergillus oryzae RIB strains", Appl. Environ. Microbiol, 72, pp.484~490 (2006)
- Yu JJ, "Completed sequence of aflatoxin pathway gene cluster in Aspergillus parasiticus", FEBS Lett, 564, pp.126~130 (2004)
- Yu J J, "Clustered pathway genes in aflatoxin biosynthesis", Appl. Environ. Microbiol, 70, pp.1253~1262 (2004)