Abstract
Aflatoxins, mainly produced by Aspergillus flavus and A. parasiticus, are a group of potent mycotoxins with carcinogenic, hepatotoxic, and immunosuppressive properties. Many studies have been devoted to investigating their biosynthesis mechanism since they were discovered half a century ago. 5-Azacytidine (5-AC), a derivative of the nucleoside cytidine and an inactivator of DNA methyltransferase, is widely used for studies in epigenetics and cancer biology, and has also been used for studying secondary metabolism in fungi. In this study, 5-AC was applied to investigate its effect on the development and aflatoxin biosynthesis of A. flavus. The results indicate that 5-AC inhibits the ability to produce aflatoxin and also causes a fluffy aconidial phenotype. Further studies revealed that 5-AC affects gene expression of A. flavus to a limited degree, and the unique homolog of DNA methyltransferase gene (DmtA) expressed constitutively during different developmental stages of A. flavus irrespective of 5-AC. This work may provide some basic data to elucidate the role of 5-AC in aflatoxin biosynthesis and the development of A. flavus.
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References
Ben-Ami R, Varga V, Lewis RE, May GS, Nierman WC, Kontoyiannis DP (2010) Characterization of a 5-azacytidine-induced developmental Aspergillus fumigatus variant. Virulence 1:164–173
He ZM, Price MS, Obrian GR, Georgianna DR, Payne GA (2007) Improved protocols for functional analysis in the pathogenic fungus Aspergillus flavus. BMC Microbiol 7:104
Hicks JK, Yu JH, Keller NP, Adams TH (1997) Aspergillus sporulation and mycotoxin production both require inactivation of the FadA G alpha protein-dependent signaling pathway. EMBO J 16:4916–4923
Holmes RA, Boston RS, Payne GA (2008) Diverse inhibitors of aflatoxin biosynthesis. Appl Microbiol Biotechnol 78:559–572
Kensler TW, Roebuck BD, Wogan GN, Groopman JD (2011) Aflatoxin: a 50-year odyssey of mechanistic and translational toxicology. Toxicol Sci 120:S28–S48
Komashko VM, Farnham PJ (2010) 5-Azacytidine treatment reorganizes genomic histone modification patterns. Epigenetics 5:229–240
Kritsky MS, Russo VE, Filippovich SY, Afanasieva TP, Bachurina GP (2002) The opposed effect of 5-azacytidine and light on the development of reproductive structures in Neurospora crassa. Photochem Photobiol 75:79–83
Lee SE, Mahoney NE, Campbell BC (2002) Inhibition of aflatoxin B1 biosynthesis by piperlongumine isolated from Piper longum L. J Microbiol Biotechnol 12:679–682
Liu SY, Lin JQ, Wu HL, Wang CC, Huang SJ, Luo YF, Sun JH, Zhou JX, Yan SJ, He JG, Wang J, He ZM (2012) Bisulfite sequencing reveals that Aspergillus flavus holds a hollow in DNA methylation. Plos One 7:e30349
Lyko F, Brown R (2005) DNA methyltransferase inhibitors and the development of epigenetic cancer therapies. J Natl Cancer Inst 97:1498–1506
Norton RA (1997) Effect of carotenoids on aflatoxin B1 synthesis by Aspergillus flavus. Phytopathology 87:814–821
Salter MG, Conlon HE (2007) Extraction of plant RNA. Methods Mol Biol 362:309–314
Song DK, Karr AL (1993) Soybean phytoalexin, glyceollin, prevents accumulation of aflatoxin B1 in cultures of Aspergillus flavus. J Chem Ecol 19:1983–1994
Tamame M, Antequera F, Villanueva JR, Santos T (1983a) 5-Azacytidine Induces heritable biochemical and developmental changes in the fungus Aspergillus niger. J Gen Microbiol 129:2585–2594
Tamame M, Antequera F, Villanueva JR, Santos T (1983b) High-frequency conversion to a “fluffy” developmental phenotype in Aspergillus spp. by 5-azacytidine treatment: evidence for involvement of a single nuclear gene. Mol Cell Biol 3:2287–2297
Tamame M, Antequera F, Santos E (1988) Developmental characterization and chromosomal mapping of the 5-azacytidine-sensitive fluF locus of Aspergillus nidulans. Mol Cell Biol 8:3043–3050
van West P, Shepherd SJ, Walker CA, Li S, Appiah AA, Grenville-Briggs LJ, Govers F, Gow NA (2008) Internuclear gene silencing in Phytophthora infestans is established through chromatin remodelling. Microbiology 154:1482–1490
Wada H, Kagoshima M, Ito K, Barnes PJ, Adcock IM (2005) 5-Azacytidine suppresses RNA polymerase II recruitment to the SLPI gene. Biochem Biophys Res Commun 331(1):93–99
Wilkinson JR, Kale SP, Bhatnagar D, Yu J, Ehrlich KC (2011) Expression profiling of non-aflatoxigenic Aspergillus parasiticus mutants obtained by 5-azacytosine treatment or serial mycelial transfer. Toxins 3:932–948
Williams RB, Henrikson JC, Hoover AR, Lee AE, Cichewicz RH (2008) Epigenetic remodeling of the fungal secondary metabolome. Org Biomol Chem 6:1895–1490
Yu J, Chang PK, Ehrlich KC, Cary JW, Bhatnagar D, Cleveland TE, Payne GA, Linz JE, Woloshuk CP, Bennett JW (2004) Clustered pathway genes in aflatoxin biosynthesis. Appl Environ Microbiol 70:1253–1262
Acknowledgements
This work was supported by National Natural Science Foundation of China (Grant no. 31170044 and 30870024) and Science and Technology Planning Project of Guangdong Province, China (grant no. 2011B020305005). We thank Prof. T.W. Hill (Rhodes College, Memphis, TN, USA) for suggestions and amendments to the paper.
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Lin, JQ., Zhao, XX., Wang, CC. et al. 5-Azacytidine inhibits aflatoxin biosynthesis in Aspergillus flavus . Ann Microbiol 63, 763–769 (2013). https://doi.org/10.1007/s13213-012-0531-7
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DOI: https://doi.org/10.1007/s13213-012-0531-7