The production of aflatoxin B1 or G1 by Aspergillus parasiticus at various combinations of temperature and water activity is related to the ratio of aflS to aflR expression (original) (raw)
Abstract
The influence of varying combinations of water activity (aw) and temperature on growth, aflatoxin biosynthesis and _afl_R/_afl_S expression of Aspergillus parasiticus was analysed in the ranges 17–42°C and 0.90–0.99 aw. Optimum growth was at 35°C. At each temperature studied, growth increased from 0.90 to 0.99 aw. Temperatures of 17 and 42°C only supported marginal growth. The external conditions had a differential effect on aflatoxin B1 or G1 biosynthesis. The temperature optima of aflatoxin B1 and G1 were not at the temperature which supported optimal growth (35°C) but either below (aflatoxin G1, 20–30°C) or above (aflatoxin B1, 37°C). Interestingly, the expression of the two regulatory genes _afl_R and _afl_S showed an expression profile which corresponded to the biosynthesis profile of either B1 (_afl_R) or G1 (_afl_S). The ratios of the expression data between _afl_S:_afl_R were calculated. High ratios at a range between 17 and 30°C corresponded with the production profile of aflatoxin G1 biosynthesis. A low ratio was observed at >30°C, which was related to aflatoxin B1 biosynthesis. The results revealed that the temperature was the key parameter for aflatoxin B1, whereas it was water activity for G1 biosynthesis. These differences in regulation may be attributed to variable conditions of the ecological niche in which these species occur.
Access this article
Subscribe and save
- Starting from 10 chapters or articles per month
- Access and download chapters and articles from more than 300k books and 2,500 journals
- Cancel anytime View plans
Buy Now
Price excludes VAT (USA)
Tax calculation will be finalised during checkout.
Instant access to the full article PDF.
Similar content being viewed by others
References
- Bennett JW, Christensen SB (1983) New perspectives on aflatoxin biosynthesis. Adv Appl Microbiol 29:53–92
Article CAS PubMed Google Scholar - Bhatnagar D, Carry JW, Ehrlich K, Yu J, Cleveland TE (2006) Understanding the genetics of regulation of aflatoxin production and Aspergillus flavus development. Mycopathologia 162:155–166
Article CAS PubMed Google Scholar - Cai J, Zeng H, Shima Y, Hatabayashi H, Nakagawa H, Ito Y, Adachi Y, Nakajima H, Yabe K (2008) Involvement of the nadA gene in formation of G-group aflatoxins in Aspergillus parasiticus. Fungal Genet Biol 45:1081–1093
Article CAS PubMed Google Scholar - Chang PK (2003) The Aspergillus parasiticus protein AFLJ interacts with the aflatoxin pathway-specific regulator AFLR. Mol Gen Genomics 268:711–719
CAS Google Scholar - Du W, Obrian R, Payne GA (2007) Function and regulation of _afl_J in the accumulation of aflatoxin early pathway intermediate in Aspergillus flavus. Food Add Contam 24:1043–1050
Article CAS Google Scholar - Ehrlich KC (2009) Predicted roles of the uncharacterized clustered genes in aflatoxin biosynthesis. Toxins 1:37–58
Article CAS Google Scholar - Ehrlich K, Cary JW (1995) An aflatoxin biosynthesis regulatory protein (AFLR) is a sequence-specific DNA binding protein. Fungal Genet Newsl 42A:57
Google Scholar - Ehrlich KC, Montalbano BG, Cary JW (1999) Binding of the C6-zinc cluster protein, AFLR, to the promoters of aflatoxin pathway biosynthesis genes in Aspergillus parasiticus. Gene 230:249–257
Article CAS PubMed Google Scholar - Faraj MK, Smith JE, Harran G (1991) Interaction of water activity and temperature on aflatoxin production by Aspergillus flavus and A. parasiticus in irradiated maize seeds. Food Add Contam 8:731–736
CAS Google Scholar - Giorni P, Magan N, Pietri A, Bertuzzi T, Battilani P (2007) Studies on Aspergillus section Flavi isolated from maize in northern Italy. Int J Food Microbiol 113:330–338
Article CAS PubMed Google Scholar - Gqaleni N, SmithJE LJ, Gettinby G (1997) Effects of temperature, water activity, and incubation time on production of aflatoxins and cyclopiazonic acid by an isolate of Aspergillus flavus in surface agar culture. Appl Environ Microbiol 63:1048–1053
CAS PubMed Google Scholar - Jurado M, Marín P, Magan N, González-Jaén MT (2008) Relationship between solute and matric potential stress, temperature, growth and FUM1 gene expression in two Fusarium verticillioides strains from Spain. Appl Environ Microbiol 74:2032–2036
Article CAS PubMed Google Scholar - Lin YC, Ayres JC, Koehler PE (1980) Influence of temperature cycling on the production of aflatoxins B1 and G1 by Aspergillus parasiticus. Appl Environ Microbiol 40:333–336
CAS PubMed Google Scholar - Magan N, Aldred D (2007a) Why do fungi produce mycotoxins? In: Dijksterhuis J, Samson RA (eds) Food mycology: a multifaceted approach to fungi and food. Taylor & Francis, Boca Raton, Fla, pp 121–133
Google Scholar - Magan N, Aldred D (2007b) Environmental fluxes and fungal interactions: maintaining a competitive edge. In: van West P, Avery S, Stratford M (eds) Stress in yeasts and filamentous fungi, Chapter 2. Elsevier, Amsterdam, pp 19–35
Google Scholar - O’Brian GR, Georgianna DR, Wilkinson JR, Yu J, Abbas HK, Bhatnagar D, Cleveland TE, Nierman W, Payne GA (2007) The effect of elevated temperature on gene transcription and aflatoxin biosynthesis. Mycologia 99:232–239
Article PubMed Google Scholar - Park KY, Bullerman LB (1981) Increased aflatoxin production by Aspergillus parasiticus under conditions of cycling temperatures. J Food Sci 46:1147–1151
Article CAS Google Scholar - Pitt JI, Hocking AD (1999) Fungi and food spoilage, 2nd edn.Aspen, Gaithersburg
- Samapundo S, De Meulenaer B, Atukwase A, Debevere J, Devlieghere F (2007) The influence of modified atmospheres and their interaction with water activity on the radial growth and fumonisin B1 production of Fusarium verticillioides and F. proliferatum on corn. Part II: The effect of initial headspace oxygen concentration. Int J Food Microbiol 113:339–345
Article CAS PubMed Google Scholar - Schmidt-Heydt M, Magan N, Geisen R (2008) Stress induction of mycotoxin biosynthesis genes by abiotic factors. FEMS Microbiol Lett 284:142–149
Article CAS PubMed Google Scholar - Schmidt-Heydt M, Abdel-Hadi A, Magan N, Geisen R (2009) Complex regulation of the aflatoxin biosynthesis gene cluster of Aspergillus flavus in relation to various combinations of water activity and temperature. Int J Food Microbiol 135:231–237
Article CAS PubMed Google Scholar - Sorensen WG, Hesseltine CW, Shotwell OL (1967) Effect of temperature on production of aflatoxin on rice by A. flavus. Mycopathologia 33:49–55
Google Scholar - 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
Article CAS PubMed Google Scholar
Acknowledgement
We would like to thank Katja Kramer and Sabine Häckel for excellent technical assistance. This work was supported by the EU project EC KBBE-2007-222690-2 MYCORED.
Author information
Authors and Affiliations
- Max Rubner Institut, Haid-und-Neu-Str. 9, 76131, Karlsruhe, Germany
Markus Schmidt-Heydt, Corinna E. Rüfer & Rolf Geisen - Applied Mycology Group, Cranfield Health, Cranfield University, Bedford, MK43 0AL, UK
Ahmed Abdel-Hadi & Naresh Magan
Authors
- Markus Schmidt-Heydt
- Corinna E. Rüfer
- Ahmed Abdel-Hadi
- Naresh Magan
- Rolf Geisen
Corresponding author
Correspondence toRolf Geisen.
Rights and permissions
About this article
Cite this article
Schmidt-Heydt, M., Rüfer, C.E., Abdel-Hadi, A. et al. The production of aflatoxin B1 or G1 by Aspergillus parasiticus at various combinations of temperature and water activity is related to the ratio of aflS to _afl_R expression.Mycotox Res 26, 241–246 (2010). https://doi.org/10.1007/s12550-010-0062-7
- Received: 17 May 2010
- Revised: 28 June 2010
- Accepted: 29 June 2010
- Published: 27 July 2010
- Issue date: November 2010
- DOI: https://doi.org/10.1007/s12550-010-0062-7