1887

Abstract

Aflatoxins are polyketide-derived secondary metabolites produced by , , and a few other species. The toxic effects of aflatoxins have adverse consequences for human health and agricultural economics. The gene, a regulatory gene for aflatoxin biosynthesis, encodes a protein containing a zinc-finger DNA-binding motif. Although and , which are used in fermented foods and in ingredient manufacture, have no record of producing aflatoxin, they have been shown to possess an gene. This study examined 34 strains of section . The gene of 23 of these strains was successfully amplified and sequenced. No PCR products were found in five strains or six strains of . These PCR results suggested that the gene is absent or significantly different in some and strains. The sequenced genes from the 23 positive strains had greater than 96·6 % similarity, which was particularly conserved in the zinc-finger DNA-binding domain. The gene of has two obvious characteristics: an extra CTCATG sequence fragment and a C to T transition that causes premature termination of AFLR protein synthesis. Differences between / and / genes were also identified. Some strains of as well as var. , var. and var. have an -type gene. For all strains with the -type gene, there was no evidence of aflatoxin production. It is suggested that for safety reasons, the gene could be examined to assess possible aflatoxin production by section strains.

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2006-01-01
2024-12-06
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References

  1. Bennett J. W, Chang P.-K, Bhatnagar D. 1997; One gene to whole pathway: the role of norsolorinic acid in aflatoxin research. Adv Appl Microbiol 45:1–15
    [Google Scholar]
  2. Cary J. W, Dyer J. M, Ehrlich K. C, Wright M. S, Liang S.-H, Linz J. E. 2002; Molecular and functional characterization of a second copy of the aflatoxin regulatory gene, aflR-2 , from Aspergillus parasiticus . Biochim Biophys Acta 1576:316–323 [CrossRef]
    [Google Scholar]
  3. Chang P.-K. 2004; Lack of interaction between AFLR and AFLJ contributes to nonaflatoxigenicity of Aspergillus sojae . J Biotechnol 107:245–253 [CrossRef]
    [Google Scholar]
  4. Chang P. K, Yu J. 2002; Characterization of a partial duplication of the aflatoxin gene cluster in Aspergillus parasiticus ATCC 56775. Appl Microbiol Biotechnol 58:632–636 [CrossRef]
    [Google Scholar]
  5. Chang P.-K, Cary J. W, Bhatnagar D, Cleveland T. E, Bevvett J. E, Line J. E, Woloshuk C. P, Payne G. A. 1993; Cloning of the Aspergillus parasiticus apa-2 gene associated with the regulation of aflatoxin biosynthesis. Appl Environ Microbiol 59:3273–3279
    [Google Scholar]
  6. Chang P.-K, Bhatnagar D, Cleveland T. E, Bennett J. W. 1995a; Sequence variability in homologs of the aflatoxin pathway gene aflR distinguishes species in Aspergillus Section Flavi . Appl Environ Microbiol 61:40–43
    [Google Scholar]
  7. Chang P.-K, Ehrlich K. C, Yu J, Bhatnagar D, Cleveland T. E. 1995b; Increased expression of Aspergillus parasiticus aflR , encoding a sequence-specific DNA-binding protein, relieves nitrate inhibition of aflatoxin biosynthesis. Appl Environ Microbiol 61:2372–2377
    [Google Scholar]
  8. Chang P.-K, Yu J, Bhatnagar D, Cleveland T. E. 1999; The carboxy-terminal portion of the aflatoxin pathway regulatory protein AFLR of Aspergillus parasiticus activates GAL1  : :  lacZ gene expression in Saccharomyces cerevisiae . Appl Environ Microbiol 65:2508–2512
    [Google Scholar]
  9. Ehrlich K. C, Cary J. W, Montalbano B. G. 1999a; Characterization of the promoter for the gene encoding the aflatoxin biosynthetic pathway regulatory protein AFLR. Biochim Biophys Acta 1444412–417 [CrossRef]
    [Google Scholar]
  10. Ehrlich K. C, Montalbano B. G, Cary J. W. 1999b; Binding of the C6-zinc cluster protein, AFLR, to the promoters of aflatoxin pathway biosynthesis genes in Aspergillus parasiticus . Gene 230:249–257 [CrossRef]
    [Google Scholar]
  11. Ehrlich K. C, Montalbano B. G, Cotty P. J. 2003; Sequence comparison of aflR from different Aspergillus species provides evidence for variability in regulation of aflatoxin production. Fungal Genet Biol 38:63–74 [CrossRef]
    [Google Scholar]
  12. Felsenstein J. 2004 phylip – Phylogenetic Inference Package, version 3.6. Distributed by the author Seattle, USA: University of Washington;
    [Google Scholar]
  13. Geiser D. M, Pitt J. I, Taylor J. W. 1998; Cryptic speciation and recombination in the aflatoxin-producing fungus Aspergillus flavus . Proc Natl Acad Sci U S A 95:388–393 [CrossRef]
    [Google Scholar]
  14. Geiser D. M, Dorner J. W, Horn B. W, Taylor J. W. 2000; The phylogenetics of mycotoxin and sclerotium production in Aspergillus flavus and Aspergillus oryzae . Fungal Genet Biol 31:1–11 [CrossRef]
    [Google Scholar]
  15. Klich M. A, Pitt J. I. 1988; Differentiation of Aspergillus flavus from A. parasiticus and other closely related species. Trans Br Mycol Soc 91:99–108 [CrossRef]
    [Google Scholar]
  16. Klich M. A, Yu J, Chang P.-K, Mullancy E. J, Bhatnagar D, Cleveland T. E. 1995; Hybridization of genes involved in aflatoxin biosynthesis to DNA of aflatoxigenic and non-aflatoxigenic aspergilli. Appl Environ Microbiol 44:439–443
    [Google Scholar]
  17. Klich M. A, Montalbano B, Ehrlich K. 1997; Northern analysis of aflatoxin biosynthesis genes in Aspergillus parasiticus and Aspergillus sojae . Appl Microbiol Biotechnol 47:246–249 [CrossRef]
    [Google Scholar]
  18. Kumeda Y, Asao T. 1996; Single-strand conformation polymorphism analysis of PCR-amplified ribosomal DNA internal transcribed spacers to differentiate species of Aspergillus section flavi . Appl Environ Microbiol 62:2947–2952
    [Google Scholar]
  19. Kurtzman C. P, Robnett M. J, Wicklow D. T. 1986; DNA relatedness among wild and domesticated species in the Aspergillus flavus group. Mycologia 78:955–959 [CrossRef]
    [Google Scholar]
  20. Kusumoto K.-I, Yabe K, Nogata Y, Ohta H. 1998a; Aspergillus oryzae with and without a homolog of the aflatoxin biosynthetic gene ver-1 . Appl Environ Microbiol 50:98–104
    [Google Scholar]
  21. Kusumoto K.-I, Yabe K, Nogata Y, Ohta H. 1998b; 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 169:303–307 [CrossRef]
    [Google Scholar]
  22. Lee C. Z, Liou G. Y, Yuan G. F. 2004; Comparison of Aspergillus flavus and Aspergillus oryzae by Amplification Fragment Length Polymorphism. Bot Bull Acad Sin 45:61–68
    [Google Scholar]
  23. Lin C. H, Tang C. H, Yuan G. F. 1995 Differentiation of Aspergillus flavus and A. oryzae. Research Report 84–982 Hsinchu, Taiwan: Food Industry Research and Development Institute;
    [Google Scholar]
  24. Matsushima K, Chang P.-K, Yu J, Abe K, Bhatnagar D, Cleveland T. E. 2001a; Pre-termination in aflR of Aspergillus sojae inhibits aflatoxin biosynthesis. Appl Microbiol Biotechnol 55:585–589 [CrossRef]
    [Google Scholar]
  25. Matsushima K, Yashiro K, Hanya Y, Abe K, Yabe K, Hamasaki T. 2001b; Absence of aflatoxin biosynthesis in koji mold (Aspergillus sojae). Appl Microbiol Biotechnol 55:771–776 [CrossRef]
    [Google Scholar]
  26. Murakami H, Hayashi K, Ushijima S. 1982; Useful key characters separating three Aspergillus taxa: A. sojae , A. parasiticus , and A. toxicarius . J Gen Appl Microbiol 28:55–60 [CrossRef]
    [Google Scholar]
  27. Page R. D. M. 1996; treeview: an application to display phylogenetic trees on personal computers. Comput Appl Biosci 12:357–358
    [Google Scholar]
  28. Payne G. A, Nystrom G. J, Bhatnagar D, Cleveland T. E, Woloshuk C. P. 1993; Cloning of the afl-2 gene involved in aflatoxin biosynthesis from Aspergillus flavus . Appl Environ Microbiol 59:156–162
    [Google Scholar]
  29. Takahashi T, Chang P.-K, Matsushima K, Yu J, Abe K, Bhatnagar D, Cleveland T. E, Koyama Y. 2002; Nonfunctionality of Aspergillus sojae aflR in a strain of Aspergillus parasiticus with a disrupted aflR gene. Appl Environ Microbiol 68:3737–3743 [CrossRef]
    [Google Scholar]
  30. Thompson J. D, Gibson T. J, Plewniak F, Jeanmougin F, Higgins D. G. 1997; The clustal x windows interface: flexible strategies for multiple sequence alignment aided by quality analysis tools. Nucleic Acids Res 25:4876–4882 [CrossRef]
    [Google Scholar]
  31. Trail F, Mahanti N, Linz J. 1995; Molecular biology of aflatoxin biosynthesis. Microbiology 141:755–765 [CrossRef]
    [Google Scholar]
  32. Watson A. J, Fuller L. J, Jeenes D. J, Archer D. B. 1999; Homologs of aflatoxin biosynthesis genes and sequence of aflR in Aspergillus oryzae and Aspergillus sojae . Appl Environ Microbiol 65:307–310
    [Google Scholar]
  33. Wei D. L, Jong S. C. 1986; Production of aflatoxins by strains of the Aspergillus flavus group maintained in ATCC. Mycopathologia 93:19–24 [CrossRef]
    [Google Scholar]
  34. White T. J, Bruns T. D, Lee S. B, Taylor J. W. 1990; Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In PCR Protocols: a Guide to Methods and Applications pp  315–322 Edited by Innis M. A., Gelfand D. H., Sninsky J. J., White T. J. San Diego: Academic Press;
    [Google Scholar]
  35. Woloshuk C. P, Prieto R. 1998; Genetic organization and function of the aflatoxin B1 biosynthetic genes. FEMS Microbiol Lett 160:169–176 [CrossRef]
    [Google Scholar]
  36. Woloshuk C. P, Foutz K. R, Brewer J. F, Bhatnagar D, Cleveland T. E, Payne G. A. 1994; Molecular characterization of aflR , a regulatory locus for aflatoxin biosynthesis. Appl Environ Microbiol 60:2408–2414
    [Google Scholar]
  37. Yu J, Chang P.-K, Cary J. W, Wright M, Bhatnagar D, Cleveland T. E, Payne G. A, Line J. E. 1995; Comparative mapping of aflatoxin pathway gene clusters in Aspergillus parasiticus and Aspergillus flavus . Appl Environ Microbiol 61:2365–2371
    [Google Scholar]
  38. Yuan G. F, Liu C. S, Chen C. C. 1995; Differentiation of Aspergillus parasiticus from Aspergillus sojae by random amplification of polymorphic DNA. Appl Environ Microbiol 61:2384–2387
    [Google Scholar]
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