Effects of Hydrogen Peroxide on Different Toxigenic and Atoxigenic Isolates of Aspergillus flavus
Drought stress in the field has been shown to exacerbate aflatoxin contamination of maize and peanut. Drought and heat stress also produce reactive oxygen species (ROS) in plant tissues. Given the potential correlation between ROS and exacerbated aflatoxin production under drought and heat stress, t...
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| Format: | Article |
| Language: | English |
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MDPI AG
2015-08-01
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| Series: | Toxins |
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| Online Access: | http://www.mdpi.com/2072-6651/7/8/2985 |
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| author | Jake C. Fountain Brian T. Scully Zhi-Yuan Chen Scott E. Gold Anthony E. Glenn Hamed K. Abbas R. Dewey Lee Robert C. Kemerait Baozhu Guo |
| author_facet | Jake C. Fountain Brian T. Scully Zhi-Yuan Chen Scott E. Gold Anthony E. Glenn Hamed K. Abbas R. Dewey Lee Robert C. Kemerait Baozhu Guo |
| author_sort | Jake C. Fountain |
| collection | DOAJ |
| description | Drought stress in the field has been shown to exacerbate aflatoxin contamination of maize and peanut. Drought and heat stress also produce reactive oxygen species (ROS) in plant tissues. Given the potential correlation between ROS and exacerbated aflatoxin production under drought and heat stress, the objectives of this study were to examine the effects of hydrogen peroxide (H2O2)-induced oxidative stress on the growth of different toxigenic (+) and atoxigenic (−) isolates of Aspergillus flavus and to test whether aflatoxin production affects the H2O2 concentrations that the isolates could survive. Ten isolates were tested: NRRL3357 (+), A9 (+), AF13 (+), Tox4 (+), A1 (−), K49 (−), K54A (−), AF36 (−), and Aflaguard (−); and one A. parasiticus isolate, NRRL2999 (+). These isolates were cultured under a H2O2 gradient ranging from 0 to 50 mM in two different media, aflatoxin-conducive yeast extract-sucrose (YES) and non-conducive yeast extract-peptone (YEP). Fungal growth was inhibited at a high H2O2 concentration, but specific isolates grew well at different H2O2 concentrations. Generally the toxigenic isolates tolerated higher concentrations than did atoxigenic isolates. Increasing H2O2 concentrations in the media resulted in elevated aflatoxin production in toxigenic isolates. In YEP media, the higher concentration of peptone (15%) partially inactivated the H2O2 in the media. In the 1% peptone media, YEP did not affect the H2O2 concentrations that the isolates could survive in comparison with YES media, without aflatoxin production. It is interesting to note that the commercial biocontrol isolates, AF36 (−), and Aflaguard (−), survived at higher levels of stress than other atoxigenic isolates, suggesting that this testing method could potentially be of use in the selection of biocontrol isolates. Further studies will be needed to investigate the mechanisms behind the variability among isolates with regard to their degree of oxidative stress tolerance and the role of aflatoxin production. |
| first_indexed | 2024-04-14T01:03:16Z |
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| institution | Directory Open Access Journal |
| issn | 2072-6651 |
| language | English |
| last_indexed | 2024-04-14T01:03:16Z |
| publishDate | 2015-08-01 |
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| spelling | doaj.art-46d016f86a0d4b32a164ed5b5304b9c42022-12-22T02:21:21ZengMDPI AGToxins2072-66512015-08-01782985299910.3390/toxins7082985toxins7082985Effects of Hydrogen Peroxide on Different Toxigenic and Atoxigenic Isolates of Aspergillus flavusJake C. Fountain0Brian T. Scully1Zhi-Yuan Chen2Scott E. Gold3Anthony E. Glenn4Hamed K. Abbas5R. Dewey Lee6Robert C. Kemerait7Baozhu Guo8Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USAUSDA-ARS, U.S. Horticultural Research Laboratory, Fort Pierce, FL 34945, USADepartment of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70803, USAUSDA-ARS, Toxicology and Mycotoxin Research Unit, Athens, GA 30605, USAUSDA-ARS, Toxicology and Mycotoxin Research Unit, Athens, GA 30605, USAUSDA-ARS, Biological Control of Pests Research Unit, Stoneville, MS 38776, USADepartment of Crop and Soil Sciences, University of Georgia, Tifton, GA 31793, USADepartment of Plant Pathology, University of Georgia, Tifton, GA 31793, USAUSDA-ARS, Crop Protection and Management Research Unit, Tifton, GA 31793, USADrought stress in the field has been shown to exacerbate aflatoxin contamination of maize and peanut. Drought and heat stress also produce reactive oxygen species (ROS) in plant tissues. Given the potential correlation between ROS and exacerbated aflatoxin production under drought and heat stress, the objectives of this study were to examine the effects of hydrogen peroxide (H2O2)-induced oxidative stress on the growth of different toxigenic (+) and atoxigenic (−) isolates of Aspergillus flavus and to test whether aflatoxin production affects the H2O2 concentrations that the isolates could survive. Ten isolates were tested: NRRL3357 (+), A9 (+), AF13 (+), Tox4 (+), A1 (−), K49 (−), K54A (−), AF36 (−), and Aflaguard (−); and one A. parasiticus isolate, NRRL2999 (+). These isolates were cultured under a H2O2 gradient ranging from 0 to 50 mM in two different media, aflatoxin-conducive yeast extract-sucrose (YES) and non-conducive yeast extract-peptone (YEP). Fungal growth was inhibited at a high H2O2 concentration, but specific isolates grew well at different H2O2 concentrations. Generally the toxigenic isolates tolerated higher concentrations than did atoxigenic isolates. Increasing H2O2 concentrations in the media resulted in elevated aflatoxin production in toxigenic isolates. In YEP media, the higher concentration of peptone (15%) partially inactivated the H2O2 in the media. In the 1% peptone media, YEP did not affect the H2O2 concentrations that the isolates could survive in comparison with YES media, without aflatoxin production. It is interesting to note that the commercial biocontrol isolates, AF36 (−), and Aflaguard (−), survived at higher levels of stress than other atoxigenic isolates, suggesting that this testing method could potentially be of use in the selection of biocontrol isolates. Further studies will be needed to investigate the mechanisms behind the variability among isolates with regard to their degree of oxidative stress tolerance and the role of aflatoxin production.http://www.mdpi.com/2072-6651/7/8/2985aflatoxindroughtoxidative stressreactive oxygen speciesbiological controlspeptone |
| spellingShingle | Jake C. Fountain Brian T. Scully Zhi-Yuan Chen Scott E. Gold Anthony E. Glenn Hamed K. Abbas R. Dewey Lee Robert C. Kemerait Baozhu Guo Effects of Hydrogen Peroxide on Different Toxigenic and Atoxigenic Isolates of Aspergillus flavus Toxins aflatoxin drought oxidative stress reactive oxygen species biological controls peptone |
| title | Effects of Hydrogen Peroxide on Different Toxigenic and Atoxigenic Isolates of Aspergillus flavus |
| title_full | Effects of Hydrogen Peroxide on Different Toxigenic and Atoxigenic Isolates of Aspergillus flavus |
| title_fullStr | Effects of Hydrogen Peroxide on Different Toxigenic and Atoxigenic Isolates of Aspergillus flavus |
| title_full_unstemmed | Effects of Hydrogen Peroxide on Different Toxigenic and Atoxigenic Isolates of Aspergillus flavus |
| title_short | Effects of Hydrogen Peroxide on Different Toxigenic and Atoxigenic Isolates of Aspergillus flavus |
| title_sort | effects of hydrogen peroxide on different toxigenic and atoxigenic isolates of aspergillus flavus |
| topic | aflatoxin drought oxidative stress reactive oxygen species biological controls peptone |
| url | http://www.mdpi.com/2072-6651/7/8/2985 |
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