Progress 10/01/00 to 09/30/05
Outputs
David Wilson at the University of Georgia worked on two objectives in this regional project(NC-129). Objective 1. Develop new techniques and improve current assays for identification and quantification of mycotoxins in cereal grains. Although different analytical methods (i.e., immunoaffinity columns, thin layer, gas and liquid chromatography) have been recommended to determine aflatoxins in food and feeds in developed countries, most of these methods are costly and complex. Therefore, a rapid, easy and inexpensive method to screen aflatoxins in peanut and corn was developed to help keep highly contaminated foods and feeds away from the marketplace in developing countries and in agricultural research on aflatoxin control. UGA in cooperation with Dr. Waltking and AOAC International developed a method that was approved as method 2005.08 Liquid Chromatographic Analysis of Aflatoxin Using Post-Column Derivatization (Modification of 991.31, 999.07 and 970.45). Objective 2.
Establish integrated strategies to manage and to prevent mycotoxin contamination in cereal grains. Georgia has defined the critical moisture levels for safe storage of pearl millet and have shown that post harvest treatments can help prolong storage under Georgia conditions. We now know the moisture contents needed for safe storage on pearl millet when there is no preservative added. The moisture contents related to relative humidities from 50 to 100% at 25C were generated for the three millet hybrids developed at Tifton. They have demonstrated that aflatoxin can be a problem in pearl millet storage and that the mycotoxins produced by fusaria are rarely a problem in storage. Georgia has also continued working with the USDA/ARS to identify resistant germplasm and to monitor the aflatoxin incidence in corn in Georgia before harvest.
Impacts
The screening method should help plant breeders and field researchers develop effective control measures for aflatoxin problems in the field and in storage. The improved method adopted as offical first action by AOAC International should improve aflatoxin assays worldwide. The definition of mycotoxin incidence in pearl millet is important worldwide and the storage studies can be applied immediately. The progress we have made in aflatoxin management in corn includes the identification of resistant genotypes and improved management practices because we now know the important environmental factors affecting aflatoxin production.
Publications
- Wilson, J.P., Jurjevic, Z., Hannah, W.W., Wilson, D.M., Potter, T.L. and Coy, A.E. Host-specific variation in infection by toxigenic fungi and contamination by mycotoxins in pearl millet and corn. Mycopathologia 161:101-106, 2005
- Waltking, A.E. and Wilson, D.M. 2005.08 Liquid Chromatographic Analysis of Aflatoxin Using Post-Column Derivatization (Modification of 991.31, 999.07 and 970.45). AOAC International, Changes in Methods. 2005.
- Holbrook,C. C., B. Z. Guo, and D. M Wilson. Breeding peanut with resistance to drought and preharvest aflatoxin contamination. Proc. Amer. Peanut Res. and Educ. Assoc. Vol 37, 2005.
- Holbrook,C. C., B. Guo, D. M. Wilson, D. G. Sullivan, E. Cantonwine, and C. K. Kvien. 2005. Progress in breeding peanut for resistance to preharvest aflatoxin contamination and drought. Proc. Aflatoxin Elimination Workshop. 2005
|
Progress 01/01/04 to 12/31/04
Outputs
Although different analytical methods (i.e., immunoaffinity columns, thin layer, gas and liquid chromatography) have been recommended to determine aflatoxins in food and feeds in developed countries, most of these methods are costly and complex. Therefore, a rapid, easy and inexpensive method to screen aflatoxins in peanut and corn was developed to help keep highly contaminated foods and feeds away from the marketplace in developing countries and in agricultural research on aflatoxin control. The developed method involved several steps including sample preparation and extraction with a relatively weak organic polar solvent (acetone-water 80:20, v/v), cleanup with anhydrous sodium sulfate and activated neutral alumina (800mg) packed in a polyethylene tube, elution with a strong organic polar solvent such as methanol (methanol, HPLC Grade), derivatization using a bromine solution, and quantification with a calibrated Fluorometer. Statistical analysis with SAS/STAT
software showed high correlations between the developed method and the immunoaffinity method (Afla Test P, manufactured by VICAM) in peanut and corn samples with adjusted R2 values of 0.96 and 0.98 respectively. The initial assessment of dollar cost for each column packed with activated alumina neutral is less than two dollars allowing a substantial cost saving. The smallest amount of aflatoxin in a peanut and corn sample that can be quantitatively determined with suitable precision and accuracy under the developed method is 6 ppb. The current maximum levels for aflatoxins set by the European Commission are 2 ppb for aflatoxin B1 and 4 ppb for total aflatoxins in peanuts, nuts, dried fruits and cereals, which are about five times lower than those established in the U.S.A. However in developing countries where local food consumption or subsistence agriculture is practiced by as much as 70 percent of the population, such threshold levels would be difficult to adhere. Thus, the developed
method can be extremely important on surveying/monitoring high levels of aflatoxin in peanut and corn to help reduce the risk to human health. Additionally, the method can also be used in research or to monitor feedstuffs since the thresholds are much more higher than those required for food consumption.
Impacts
The screening method should help plant breeders and field researchers develop effective control measures for aflatoxin problems in the field and in storage.
Publications
- TIMPER, P., D. M. WILSON, C. C. HOLBROOK, and B. W. MAW. 2004. Relationship between Meloidogyne arenaria and aflatoxin contamination in peanut. J. Nematol. 36(2):167-170.
- BUNTIN, G. DAVID, JOHN N. ALL, R. DEWEY LEE, and DAVID M. WILSON. 2004. Plant-incorporated Bacillus thuringiensis resistance for control of fall armyworm and corn earworm (Lepidoptera: Noctuidae) in corn. J. Econ. Entomol. 97(5):1603-1611.
- JURJEVIC, Z., D. M. WILSON, J. P. WILSON, and M. COULIBALY. 2004. Fungi and mycotoxins associated with pearl millet from 1996 to 2002. Phytopathology 94:S48 (Abstr.).
- JURJEVIC, Z., M. TERTULIANO, G. C. RAINS, D. M. WILSON, C. C. HOLBROOK, and W. J. LEWIS. 2004. A comparison of volatile metabolites produced by aflatoxin-tolerant and aflatoxin-susceptible peanut plants. Phytopathology 94:S48 (Abstr.).
- AUGUSTO, JOAO, MAMADOU COULIBALY, DAVID M. WILSON, CORLEY HOLBROOK, and NEIL W. WIDSTROM. 2004. Screening method for determination of aflatoxins in peanut and corn. AOAC International Annual Meeting, September 19-23, 2004, St. Louis, Missouri (Abstr.).
- HOLBROOK, C. C., B. Z. GUO, D. M. WILSON, X. LIANG, M. LUO, P. TIMPER, H. Q. XUE, and T. ISLEIB. 2004. Tools for breeding peanut with resistance to preharvest aflatoxin contamination. Program of the 4th Annual Fungal Genomics, 5th Annual Multi-Crop Fumonisin, 17th Annual Multi-Crop Aflatoxin Elimination Workshops, October 25-28, 2004, Sacramento, CA. (Abstr.).
- TIMPER, P., D. M. WILSON, and C. C. HOLBROOK. 2004. The influence of pod and root galling by root-knot nematodes on preharvest aflatoxin contamination of peanut. Program of the 4th Annual Fungal Genomics, 5th Annual Multi-Crop Fumonisin, 17th Annual Multi-Crop Aflatoxin Elimination Workshops, October 25-28, 2004, Sacramento, CA. (Abstr.).
- AUGUSTO, J., M. COULIBALY, D. M. WILSON, C. HOLBROOK, and N. W. WIDSTROM. 2004. Screening method for determination of aflatoxins in peanut and corn. Program of the 4th Annual Fungal Genomics, 5th Annual Multi-Crop Fumonisin, 17th Annual Multi-Crop Aflatoxin Elimination Workshops, October 25-28, 2004, Sacramento, CA. (Abstr.).
|
Progress 01/01/03 to 12/31/03
Outputs
We have made much progress in the last three years on developing an inexpensive aflatoxin screening method suitable for use in field research. This is part of Joao Augustos thesis research.The primary emphasis has been on cost and the ease of use. A lot of analytical data must be available to assist in the development of management approaches for mycotoxins. Plant breeders can generate thousands of samples which must be analyzed individually, other field management strategies require fewer analyses but the analytical results must be generated in a short time. Therefore this research effort has had a high priority. We think that the method we are in the final stages of development will cost less than one dollar per analysis compared to the currently used method which costs ten dollars per analysis. We think that the data which costs a dollar per plot will be just as useful as the data that costs ten dollars per plot. This research has been in cooperation with USDA/ARS
Tifton, and has been supported by the National Peanut Board, the peanut CRSP and the University of Nebraska/ INTSORMIL CRSP as well as the UGA Hatch project. Very little has been published on storage of pearl millet and the database is very limited. We have defined the critical moisture levels for safe storage of pearl millet and have shown that post harvest treatments can help prolong storage under Georgia conditions. We now know the moisture contents needed for safe storage on pearl millet when there is no preservative added. The moisture contents related to relative humidities from 50 to 100% at 25C were generated for the three millet hybrids developed at Tifton. We have demonstrated that aflatoxin can be a problem in pearl millet storage and that the mycotoxins produced by fusaria are rarely a problem in storage.
Impacts
The screening method should help plant breeders and field researchers develop effective control measures for aflatoxin problems in the field and in storage.
Publications
- WIDSTROM, N. W., A. BUTRON, B. Z. GUO, D. M. WILSON, M. E. SNOOK, T. E.CLEVELAND, and R. E. LYNCH. 2003. Control of preharvest aflatoxin contamination in maize by pyramiding QTL involved in resistance to ear-feeding insects and invasion by Aspergillus spp. Eur. J. Agron. 19(4):563-572
- WIDSTROM, N. W., B. Z. GUO, and D. M. WILSON. 2003. Integration of crop management and genetics for control of preharvest aflatoxin contamination of corn. J. Toxicol., Toxin Rev. 22(2/3):195-223.
- JURJEVIC, Z., D.M. WILSON, J.P. WILSON, G.C. RAINS, D.M. GEISER, and N. WIDSTROM. 2003. Fusarium species on Georgia corn and pearl millet and its relation with fumonisin production. Phytopathology 93(6):S42
- JURJEVIC, Z., M. TERTULIANO, J.K. TOMBERLIN, G.C. RAINS, D.M. WILSON, and W.J. LEWIS. 2003. Volatile metabolites associated with Aspergillus species. Phytopathology 93(6):S42
- Timper, P, D.M. Wilson, and C.C. Holbrook. 2003. Root-knot nematodes and preharvest aflatoxin contamination in peanut. Aflatoxin Workshop, Savannah, GA
- C. C. Holbrook1, B. Z. Guo2, D. M. Wilson, M.. Luo, and X. Liang. 2003. Breeding Peanut for Resistance to Preharvest Aflatoxin Contaminationand Drought Tolerance. Aflatoxin Workshop, Savannah, GA
|
Progress 01/01/02 to 12/31/02
Outputs
one of the goals of this project is to develop an inexpensive aflatoxin screening method for use in field research. The primary emphasis has been on cost and ease of use. A lot of analytical data must be available to assist in the development of management approaches. Plant breeders can generate thousands of samples while other field management strategies require fewer analyses but the analytical results must be generated in a short time. The method will cost less than one dollar per analysis compared to the currently used method which costs ten dollars per analysis. The data which costs a dollar per plot will be just as useful as the data that costs ten dollars per plot. This research has been in cooperation with USDA/ARS Tifton and the peanut CRSP project in Botswana. The Univerity of Georgia is just finishing the projects on mycotoxin contamination and the storability of Pearl millet. This has been a cooperative project with USDA/ARS, Tifton, North Dakota State
University, Pennsylvania State University, MRC - PROMEC, South Africa and UGA. Very little has been published on storage of pearl millet and the database is very limited. We have defined the critical moisture levels for safe storage of pearl millet and have shown that post harvest treatments can help prolong storage under Georgia conditions. We now know the moisture contents needed for safe storage on pearl millet when there is no preservative added. The moisture contents related to relative humidities from 50 to 100% at 25C were generated for the three millet hybrids developed at Tifton. We have demonstrated that aflatoxin can be a problem in pearl millet storage and that the mycotoxins produced by fusaria are rarely a problem in storage. However, low concentrations of fusaria mycotoxins, including some of the trichothecenes, zearalenone, beauvericin and moniliformin may occur before harvest. The fumonisins apparently are not produced in pearl millet in Georgia. We have identified
Fusarium pseudonygami in Georgia grown preharvest pearl millet, this is the first observation of this fungus in North America in pearl millet. The high moisture pearl millet that was treated with propionic acid or ammonium propionate was stored for at least 7 months with no apparent fungal deterioration and no further mycotoxin buildup occurred. The propionic acid treatment was corrosive as expected and the ammonium propionate was not corrosive. The product treated with ammonium propionate developed a pleasant fruity odor that most likely would be well accepted by consuming animals. The compounds that were produced in these treatments were identified by GC/MS headspace analysis. The primary compounds in the propionic acid treatment were propionic acid and smaller amounts of acetic acid and other compounds. In the ammonium propionate treatment the primary volatile chemical was ethyl propionate. It is interesting that this compound is one of the principal odor compounds associated with
the smell of apples. Ammonium propionate is already used as a feed additive in poultry feed in Georgia. Therefore, this research will have applications in many grains far beyond the pearl millet applications.
Impacts
The use of one of several beta-cyclodextrin compounds instead of bromine to improve the fluorescence of the aflatoxins has resulted in the initial development of a promising screening tool that costs less than $0.50 per sample in recurring expense as compared to the currently used methods which cost over $5.00 per sample. The screening method is a qualitative method designed for research applications and is not suitable for regulatory applications. The method is currently being refined and should be ready for use in the 2003 crop year in Georgia. In the millet storage studies, both of the propionic acid treatments resulted in mold free grain after storage. The propionic acid treatment contained mostly propionic acid after 7 months and the ammonium propionate contained primarily the ethyl ester of propionic acid after 10 months. The propionic acid treated grain smelled like vinegar and the ammonium propionate treated grain had a fruity pleasant odor. It is very likely
that this product will be of use for many grain crops in the poultry industry in Georgia.
Publications
- Wilson DM, Mubatanhema W, Jurjevic Z. Biology and ecology of mycotoxigenic Aspergillus species as related to economic and health concerns. Advances in Experimental Medicine and Biology. 504: 3-17, 2002
- Wilson, David M. 2002. Methods for aflatoxin detection in research, p. 60-62. IN:. Summary Proceedings of the Seventh ICRISAT Regional Groundnut Meeting for Western and Central Africa, 6-8 December 2000, Cotonou, Benin. Editors, Farid Waliyar and Moustapha Adomou. ICRISAT (International Crops Research Institute for the Semi-Arid Tropics), Patancheru 502 324, Andhra Pradesh, India.
- Holbrook, C. Corley, David M. Wilson, and Michael E. Matheron. 2002. Breeding groundnut for resistance to preharvest aflatoxin contamination, p. 24-26. IN:. Summary Proceedings of the Seventh ICRISAT Regional Groundnut Meeting for Western and Central Africa, 6-8 December 2000, Cotonou, Benin. Editors, Farid Waliyar and Moustapha Adomou. ICRISAT (International Crops Research Institute for the Semi-Arid Tropics), Patancheru 502 324, Andhra Pradesh, India.
- Wilson, D.M. 2002. Progress and pitfalls in aflatoxin studies. IMC7 Book of Abstracts, The 7th International Mycological Congress, Oslo, Norway, 11-17 August 2002, p. 130.
- Lewis, W. Joe, D.M. Wilson, and G.C. Rains. 2002. Parasitoid learning/food safety application: background and overview. Annual Meeting of the Entomological Society of America, November 17-20, 2002, Fort Lauderdale, Florida.
- Tomberlin, Jeffery K., Z. Jurjevic, and Moukaram Tertuliano. 2002. Parasitoid learning/food safety application: distinguishing aflatoxin-producing fungi. Annual Meeting of the Entomological Society of America, November 17-20, 2002, Fort Lauderdale, Florida.
- Jurjevic, Z., Jeffery K. Tomberlin, and Moukaram Tertuliano. 2002. Parasitoid learning/food safety application: volatiles associated with fungi. Annual Meeting of the Entomological Society of America, November 17-20, 2002, Fort Lauderdale, Florida.
- Tertuliano, Moukaram, Jeffery K. Tomberlin, and Z. Jurjevic. 2002. Parasitoid learning/food safety application: behavioral responses to indicator compounds. Annual Meeting of the Entomological Society of America, November 17-20, 2002, Fort Lauderdale, Florida.
- Rains, G.C., W. Joe Lewis, and D.M. Wilson. 2002. Parasitoid learning/food safety application: future direction and application. Annual Meeting of the Entomological Society of America, November 17-20, 2002, Fort Lauderdale, Florida.
- Siame, A.B. and J.U. Laing. 2002. Aflatoxin and cyclopiazonic acid contamination of peanuts in Botswana. Mycopathologia 155(1-2):56
- Ingram, Keith, Corley Holbrook, Arthur Wiessinger, and Dave Wilson. 2002. Using green fluorescent protein producing strains of Aspergillus flavus to assess aflatoxin resistance of peanut under drought. Mycopathologia 155(1-2):114
- Lewis, W. Joe, Glen C. Rains, and David M. Wilson. 2002. Trained wasps as chemical detectors: application for aflatoxin-related issues. Aflatoxin/Fumonisin Elimination and Fungal Genomics Workshop 2002, October 23-25, 2002, San Antonio, Texas.
- Wilson, David M., Joao Augusto, Corley Holbrook, and Neil Widstrom. 2002. Using cyclodextrins in a rapid inexpensive aflatoxin screening method for field research applications. Aflatoxin/Fumonisin Elimination and Fungal Genomics Workshop 2002, October 23-25, 2002, San Antonio, Texas.
- Holbrook, C. Corley, Baozhu Guo, David M. Wilson, C.K. Kvien, Weibo Dong, Diane L. Rowland, and Meng Luo. 2002. Selection of peanut breeding lines with resistance to preharvest aflatoxin contamination and improved drought tolerance. Aflatoxin/Fumonisin Elimination and Fungal Genomics Workshop 2002, October 23-25, 2002, San Antonio, Texas.
- Wilson, J.P., C.C. Holbrook, L. Wells, B. Mandal, D. Rowland, and D.M. Wilson. 2002. Effect of foliar applications of particle films on drought stress and aflatoxin contamination of peanut. Aflatoxin/Fumonisin Elimination and Fungal Genomics Workshop 2002, October 23-25, 2002, San Antonio, Texas.
- Timper, Patty, David M. Wilson, and C. Corley Holbrook. 2002. Relationship between pod galling from root-knot nematodes and aflatoxin contamination in peanut. Aflatoxin/Fumonisin Elimination and Fungal Genomics Workshop 2002, October 23-25, 2002, San Antonio, Texas.
- Dong, Weibo, C. Corley Holbrook, Baozhu Guo, Meng Luo, David M. Wilson, Craig K. Kvien, and Diane L. Rowland. 2002. Evaluation of physiological measures of drought stress to indirectly select for reduced aflatoxin contamination in peanut. Aflatoxin/Fumonisin Elimination and Fungal Genomics Workshop 2002, October 23-25, 2002, San Antonio, Texas.
- Wilson, J.P., W.W. Hanna, D.M. Wilson, and A.E. Coy. 2002. Differences in pre-harvest infection by toxigenic fungi in dryland pearl millet and corn. Aflatoxin/Fumonisin Elimination and Fungal Genomics Workshop 2002, October 23-25, 2002, San Antonio, Texas.
|
Progress 01/01/01 to 12/31/01
Outputs
Corn or peanut samples can be extracted with 80% methanol and 20% water. The method uses one gram sample matrix to two milliliters of extraction solvent with 1 percent NaCl added before extraction. The extracted sample is filtered and five ml of the extract is diluted with 20 ml water and then filtered after one minute. The resulting filtrate is then directly injected into the HPLC system using a reversed phase column and detected using fluorescence detection. The correlations between the Vicam fluorometric method and this screening by HPLC were excellent. The correlations were above 0.95 for the HPLC and Afla P and Afla B columns for peanut and above 0.92 for the HPLC and Afla P columns for corn. This inexpensive approach using current HPLC technology could result in improved data collection from field research efforts. Corn samples were randomly collected on farms before harvest from 41-43 counties in south Georgia from 1996 to 2000. Analyses of fumonisins
(FB1+FB2+FB3) and aflatoxins (B1+B2+G1+G2) were carried out using HPLC and the Vicam aflatest fluorometer method respectively. There was a high incidence of fumonisin contamination of corn from the five harvest seasons. In the 1996 samples, 86% of the corn samples had fumonisin concentrations ranging from 0.6 to 30.2 ppm. In the 1997 samples 63% were contaminated with fumonisins, ranging from 1.0 to 22.7 ppm. In the 1998 samples 91% of the samples were contaminated with fumonisins ranging from 1.3 to 33.3 ppm. In the 1999 corn samples, 67% of the samples had fumonisin concentrations ranging from 0.1 to 16.5 ppm. All of the 1996 samples contained detectable aflatoxins, ranging from 5 ng/g to 430 ng/g, with ten of the samples having an aflatoxin concentration less than 10 ng/g. On the 1997 corn samples, 85% of the samples were contaminated with aflatoxins but only 12% of the samples had aflatoxins concentrations above 10 ng/g. Aflatoxin concentration in contaminated samples ranged from
1 ng/g to 130 ng/g. The 1998 corn samples were all contaminated with aflatoxins, with concentrations ranging from 6 ng/g to 3500 ng/g with 95 % of the samples having concentrations above 10ng/g. All the 1999 corn samples had aflatoxin contamination, with concentrations ranging from 1 to 530 ng/g. Seven samples had aflatoxin concentrations above 10 ng/g. The 2000 crop contained aflatoxins from 0 to 440 ppb of aflatoxin. When data from all five harvest seasons was combined, ear damage was correlated with both fumonisin and aflatoxin content and there was a significant positive correlation between fumonisin and aflatoxin contamination although this was not always the case in the year by year analysis. The industry and scientific community needs to develop uniform standards for reporting results concerning aflatoxin contamination and fungal incidence in biocontrol studies. The results need to be presented in ppb and the fungal field studies need to be logical and based on the probable
fate and persistence of the biocontrol fungi in the environment. The studies need to take into account the agricultural, marketing, storage, manufacturing and consumer environments as well as regulations and human health concerns.
Impacts
The emphasis on methods development in 2001 was to develop a rapid inexpensive screening method for aflatoxin research by non-chemists. This rapid method developed is able to detect the toxin in peanuts and corn from very low amounts (10 ppb) to very high amounts (50,000 ppb). The method is very rapid and uses currently available equipment and is cost efficient. We hope that the adoption of this method in field research will save many thousands of dollars in field and storage research designed to develop control measures for aflatoxin management. The moisture levels for safe storage of millet in our states climate have been determined from the field dried crop and the stored product that is remoistened. The safe storage moisture content is around 13-14% moisture at 25 degrees C. The use of propionic acid or ammonium propionate is very effective in maintaing a mycotoxin free product in storage. We think that this information will help develop a market for millet in
poultry rations.
Publications
- Mubatanhema, W. and Wilson, D.M., 2001. Detection, Control and Management of Mycotoxins in Southern Africa, A Training Manual , Published on the Peanut CRSP web page. 71 pages.
- Holbrook, C.C., Kvein, C.K., Rucker, K.S., Wilson, D.M., Hook, J.E. and Matheron, M.E. 2000. Preharvest aflatoxin contamination in drought-tolerant and drought-intolerant peanut genotypes. Peanut Science 27:45-48.
- Mubatanhema, W, Wilson, D.M.., Widstom, N.W. and Holbrook, C.C., 2001 (abstract), A simplified HPLC method for field and research screening of aflatoxin in corn and peanut. Aflatoxin Elimination Workshop, Phoenix, AZ
- Mubatanhema, W., Jurjevic, Z.,Wilson D.M., Widstrom, N.W., Meridith F. and Evans,B., 2001 (abstract), Fumonisins and aflatoxins in preharvest corn in south Georgia: A five year survey. Aflatoxin Elimination Workshop, Phoenix, AZ
- Wilson, D.M., 2001(abstract), The need for uniform standards, methods and reporting of data from biocontrol studies using atoxigenic Aspergillus flavus and A. parasiticus. Aflatoxin Elimination Workshop, Phoenix, AZ
- Mubatanhema, W, Wilson, D.M.., Widstom, N.W. and Holbrook, C.C., 2001 (abstract), A simplified HPLC method for field and research screening of aflatoxin in corn and peanut. AOAC International, Kansas City,MO
- Trucksess, M.W., Whitaker, T.B., van Egmond, H.P., Wilson, D.M., Solfrizzo, M., Abramson, D., Dorner, J.W., Ware, G.M., Maragos, C.M., Hald, B., Sabino, M., Eppley, R.M. and Hagler, W.M. 2001 (abstract), Mycotoxin report. AOAC International, Kansas City, MO
- Buntin, G.D., Lee, R.D., Wilson, D.M. and McPherson, R.M. 2001. Evaluation of yeildguard transgenic resistance for control of fall armyworm and corn earworm (Lepidoptera: Noctuidae) on corn. Florida Entomoligist 84:38-42.
- Punia, R. C., Dahiya, O. S., Wilson, D. M., and Wilson, J. P. 2000. Propionic acid treatment prolongs storage and reduces rancidity of pearl millet feed grain. International Sorghum and Millets Newsletter 41:80-81.
|
Progress 01/01/00 to 12/31/00
Outputs
Progress on this project has been made in several areas. First, a new simple method for aflatoxin analysis by HPLC has been developed and evaluated in corn and peanuts. This method uses a simple extraction followed by HPLC using fluorescence detection. The method is useful for screening of field research samples for aflatoxin concentrations between zero and 50,000 ppb in corn and peanut. The sample preparation costs are minimal and the method can be automated. The second area of research was to evaluate the interactions of Fusarium moniliforme and Aspergillus flavus in corn. The fungi occur together and the conditions for fumonisin and aflatoxin contamination before harvest are similar for both mycotoxins. There is little actual interaction in non-inoculated corn between the incidence of the fungi, but when corn is inoculated with one of the fungi then the incidence of the other is lowered. This apparent interaction seems to be an experimental artifact that has little
meaning in farmers fields. The use of the Bt gene in corn does not affect the aflatoxin content in corn at harvest in either Georgia or Florida so this is not a useful approach for mycotoxin control. Pearl millet will accumulate aflatoxins when stored under high moisture conditions, but the application of 1% propionic acid does not allow the fungus to grow and produce aflatoxins.
Impacts
The simplified aflatoxin assay for field studies will make it much easier and cheaper to generate relevant and accurate data in field experiments in corn and peanut. The introduction of the Bt gene into corn will not reduce aflatoxin content in corn in Georgia. Pearl millet can apparently be safely stored at high moisture with the application of propionic acid similar to its use in other feed grains.
Publications
- Holbrook, C. C., Wilson, D. M.. Matheron, M. E., Hunter, J. E., Knauft, D. A. and Gorbet, D. W. 2000. Aspergillus colonization and aflatoxin contamination in peanut genotypes with reduced linoleic acid composition. Plant Disease 84:148-150.
- Mubatanhema, W. Moss, M. O., Frank, M. J. and Wilson, D. M. 1999. Prevalence of Fusarium species of the Liseola section on Zimbabwean corn and their ability to produce the mycotoxins zearalenone, moniliformin and fumonisin B1. Mycopathologica 148:157-163. (the date of the journal is incorrect but all of Vol 148 is dated 1999 and should be 2000).
- Punia, R. C., Dahiya, O. S., Wilson, D. M., and Wilson, J. P. 2001. Propionic acid treatment prolongs storage and reduces rancidity of pearl millet feed grain. International Sorghum and Millets Newsletter (In Press).
- Mubatanhema W., Jurjevic Z., Wilson D. M., Widstrom N., Meredith F. and Evans B. 2000. Occurrence of fumonisins and aflatoxins in the south Georgia corn survey from 1996 to 1999. Fumonisins: Risk Assessment Workshop. College Park, MD (Abstract)
- Mubatanhema W., Jurjevic Z., Wilson D. M., Widstrom N. E. and Evans B. 2000. Mycofloral analysis of preharvest south Georgia corn survey from 1996 to 1999. Fumonisins: Risk Assessment Workshop. College Park, MD (Abstract)
- Wilson, J.P., Juvevic, Z, Wilson, D. M. and Casper,H. 2000. Fungal and mycotoxin contamination of stored pearl millet grain. APS Southern Division meeting. Gainesville, FL (Abstract)
- Wilson, D. M., Mubatanhema, W. and Jurjevic, Z. 2000. Biology and ecology of mycotoxigenic Aspergillus species as related to economic and health concerns. American Chemical Society symposium on mycotoxins. Washington, DC (Abstract)
- Wilson, D. M. 2000. Current methods for the analysis of aflatoxins and assessing toxigenic species of the Aspergillus flavus group. AOAC International Odette Shotwell Memorial symposium on mycotoxins, Philadelphia, PA (Abstract)
- Holbrook, C. C. Kvein, C. K., Xue, H, Wilson, D. M., Matheron M. E. and Wauchope, R. D. 2000. Preharvest aflatoxin contamination in drought tolerant and drought intolerant peanut genotypes. Aflatoxin Workshop. Yosemite, CA, October, 2000 (Abstract)
- Guo, B. Z., Burton, A., Widstrom, N. W., Wilson, D. M., Snook, M. E., Lee, R. D., Cleveland, T. E. and Lynch, R. E. 2000. Identification and pyramiding genes/markers associated with corn ear resistance to insects and Aspergillus flavus for control of preharvest aflatoxin contamination in corn. Aflatoxin Workshop. Yosemite, CA, October, 2000 (Abstract)
- Burton, A. Guo, B. Z., Widstrom, N. W., Snook, M. E., Wilson, D. M. and Lynch, R. D. 2000. Markers associated with silk antibiotic compounds, husk coverage and aflatoxin concentrations in two mapping populations. Aflatoxin Workshop. Yosemite, CA, October, 2000 (Abstract)
- Wilson, D. M. 2000. Aflatoxin measurement in research. ICRISAT 7th Regional Groundnut Workshop for West and Central Africa. Cotonou, Benin, December, 2000 (Abstract)
- Widstrom, N. W., Burton, A. Guo, B., Wilson, D. M., Snook, M., Cleveland, T. and Lynch, R., 2000, Control of aflatoxin contamination in maize through pyramiding resistance genes to ear-feeding insects and invasion by Aspergillus spp., 3rd International Crop Science Congress 2000, Hamburg, Germany (Abstract)
- Buntin, G. D., All, J. L. and Wilson, D. M., 2000, Assessment of transgenic Bt resistance for control of fall armyworm and corn earworm infestations and reduction of aflatoxin contamination of corn, XXI International Congress of Entomology, Foz de Iguacu, Brazil (Abstract)
- Buntin, G. D., All, J. N., Wilson, D. M. and Lee, R. D., 2000. Evaluation of 'YieldGard' corn for control of fall armyworm and corn earworm in Georgia, SE Branch of Entomological Society of America, Mobile, AL (Abstract)
|
Progress 01/01/99 to 12/31/99
Outputs
Corn samples were randomly collected before harvest from 41- 43 counties in south Georgia from 1996 to 1999. Analyses of fumonisins and aflatoxins were carried out on the corn. There was a high incidence of fumonisin contamination from the four harvest seasons. In the 1996, 1997, 1998, and 1999 seasons 86%, 63%, 91%, and 67% of the samples contained fumonisins respectively. The 1998 crop year was the worst year for aflatoxin contamination but aflatoxin contamination was seen in all years. When data from all years was combined, ear damage was correlated with both fumonisin and aflatoxin content and there was a significant positive correlation between fumonisin and aflatoxin contamination although this was not the case in the year by year analysis. Pearl millet (Pennisetum glaucum) samples from the 1996, 1997, and 1998 crop years were kept in experimental storage conditions to analyze fungal succession and mycotoxin development. The most frequently isolated fungi
respectively were Fusarium semitectum, Fusarium chlamydosporum, Alternaria spp., Aspergillus flavus, Curvularia spp., and Helminthosporium spp. Fungi that occurred less frequently included Aspergillus niger, other Aspergillus spp., Cladosporium herbarum, Cerebella andropogonis, Epicoccum spp., Fusarium verticillioides, Gloeocercospora sorghi, Penicillium spp., Phyllosticta spp., Phycomyces spp., Rhizopus spp., yeasts, and other fungi. Aflatoxins were found in all three years in different amounts depending on year and storage conditions. Aflatoxin amounts ranged from 5 ng/g to 1750 ng/g. Highest amounts of aflatoxins were detected in Pearl millet seeds from 1996 that contained 20% moisture and were stored at 25C. Low levels of deoxynivalenol (0-0.3 micrograms/g), nivalenol (0-0.4 micrograms/g), and zearalenone (0-0.4 micrograms/g) were detected.
Impacts
The correlation of ear damage with both aflatoxin and fumonisin contamination in Georgia grown corn is of importance because this indicates that crop management approaches may help minimize the impact of mycotoxin contamination in Georgia corn. This is the first study that has demonstrated the co-occurrence of these mycotoxins in corn. The studies on Pearl millet demonstrated that storage systems are important and that Pearl millet is susceptible to mycotoxin contamination under adverse storage conditions.
Publications
- Mubatanhema, W. and Wilson, D. M.. 1999. A comparison of the suppression of aflatoxin production in liquid cultures of Aspergillus flavus NRRL 5520 by Fusarium moniliforme, Aspergillus niger, Rhizopus and a low aflatoxin producing Aspergillus flavus strain NRRL 5565. Am Peanut Res Edu (Abstract)
- Mubatanhema, W., Jurjevic, Z., Wilson, D. M., Widstrom, N., Meredith, F. and Evans, B. 1999. Occurrence of fumonisins and aflatoxins in the south Georgia corn survey from 1996 to 1999. AOAC Int. (Abstract)
- Wilson, D. M, Widstrom, N. W., Brock, J., Mubatanhema, W. and Evans, B. 1999. Summary of studies using the norsolorinic acid producing Aspergillus parasiticus mutant to study infection and visually screen for aflatoxin resistance in corn. Aflatoxin Elimination Workshop (Abstract)
- Wauchope, D., Ho, A., Holbrook, C. C., Haney, B., Mubatanhema, W. and Wilson, D. M. 1999. Rapid and sensitive analytical methods for aflatoxins: An Update. Aflatoxin Elimination Workshop (Abstract)
- Widstrom, N. W., Burton, A., Guo, B., Wilson, D. M., Snook, M. E., and Cleveland, T. E. 1999. Pyramiding ear resistance to insects and invasion by Aspergillus spp. For control of preharvest aflatoxin contamination. Aflatoxin Elimination Workshop (Abstract)
- Holbrook, C. C., Kvein, C. K., Franke, K. K., Wauchope, D., Xue, H., Matheron, M. E. and Wilson, D. M. 1999. The search for an indirect selection tool for resistance to preharvest aflatoxin contamination in peanut. Aflatoxin Elimination Workshop (Abstract)
- Wilson, D. M. and Trucksess, M. W. 1999. The status of official AOAC International, AOAC Research Institute certified and FGIS protocol methods for aflatoxin determination as the relate to current United States and European Union aflatoxin regulations for grain, oilseed, cottonseed and tree nuts. Aflatoxin Elimination Workshop (Abstract)
- Kisyombe, C. T. and Wilson, D. M.. 1999. Differences in the occurrence of Aspergillus flavus in peanut in Malawi tests of cultivars and locations. Aflatoxin Elimination Workshop (Abstract)
- Wilson, D. M., Wright, D. L., Wiatrak, P., Herzog, D., Buntin, G. D. and Lee, D. 1999. Comparison of preharvest aflatoxin accumulation in Bt and non-Bt corn in Florida and Georgia. Aflatoxin Elimination Workshop (Abstract)
- Jurjevic, Z., Wilson, D. M., Wilson, J. P., and Casper, H. 1999. Fungal successions in stored Pearl millet. Aflatoxin Elimination Workshop (Abstract)
|
Progress 01/01/98 to 12/31/98
Outputs
It is estimated that approximately one-third of the 1998 corn crop intended for grain production in Georgia was not harvested due to drought, aflatoxin contamination, or both. Samples of pre-harvest grain randomly collected from 43 South Georgia counties where more than 95 percent of the state's crop is produced revealed levels of aflatoxin contamination ranging from 6 to 5,500 ppb with an overall average of 236 ppb. A gradient of sample contamination across the Coastal Plain was not readily apparent nor were hot spots easily detected. The samples were also analyzed for fumonisin contamination. Fumonisin amounts ranged from 1000 ppb to 33000 ppb. Results showed a significant correlation between the presence of fumonisins and that of aflatoxins, suggesting that the environmental conditions were favorable for the growth and subsequent mycotoxin production by both Aspergillus and Fusarium species. Aflatoxin and fumonisin amounts showed a significant correlation with both
ear damage (cm tip penetration) and to the percentage of damaged ears although the respective fungal flora did not show the same correlation pattern. There was also a strong correlation between the occurrence of fumonisin B1 with both fumonisin B2 and B3.It is estimated that approximately one-third of the 1998 corn crop intended for grain production in Georgia was not harvested due to drought, aflatoxin contamination, or both. Samples of pre-harvest grain randomly collected from 43 South Georgia counties where more than 95 percent of the state's crop is produced revealed levels of aflatoxin contamination ranging from 6 to 5,500 ppb with an overall average of 236 ppb. A gradient of sample contamination across the Coastal Plain was not readily apparent nor were hot spots easily detected. The samples were also analyzed for fumonisin contamination. Fumonisin amounts ranged from 1000 ppb to 33000 ppb. Results showed a significant correlation between the presence of fumonisins and that of
aflatoxins, suggesting that the environmental conditions were favorable for the growth and subsequent mycotoxin production by both Aspergillus and Fusarium species. Aflatoxin and fumonisin amounts showed a significant correlation with both ear damage (cm tip penetration) and to the percentage of damaged ears although the respective fungal flora did not show the same correlation pattern. There was also a strong correlation between the occurrence of fumonisin B1 with both fumonisin B2 and B3.
Impacts
(N/A)
Publications
- Wilson, D.M., Sydenman, E.W., Lombaert, G.A., Trucksess, M.W., Abramson, D.A. and Bennet, G.A. 1998. Mycotoxin analytical techniques. Mycotoxins in Agriculture and Food Safety.Marcel Dekker, NY Pp. 135-182.
- Holbrook, C.C., Wilson, D.M., Matheron, W.E. and Anderson, W.F. 1997. Aspergillus colonization and aflatoxin contamination in peanut genotypes with resistance to other fungal pathogens. Plant Dis. 81:1429-1431.
- Widstrom, Neil W. and Wilson, David M. 1998. A role for the nor mutant of Aspergillus parasiticus in a breeding program--contamination of corn. Aflatoxin Elimination Workshop, St. Louis, Abstract.
- Wilson, David M., Widstrom, Neil W., Holbrook, C. Corley, Matheron, Mike E., Will, M. Elizabeth and Brock, Jason H. 1998. Utility of--inoculum. Aflatoxin Elimination Workshop, St. Louis, Abstract.
- Holbrook, Corley C., Wilson, David M., Matherson, M.E., and Wauchope, R.D. 1998. Searching for a silver bullet in a haystack. Aflatoxin Elimination Workshop, St. Louis, Abstract.
- Guo, Baozhu Z., Widstrom, Neil W., Rugang Li, Peisheng Cong, Lynch, Robert E., Snook, Maurice E., Wilson, David M., and Cleveland, Thomas E. 1998. Pyramiding resistance to Aspergillus flavus and corn earworm to control preharvest aflatoxin contamination: Genetic mapping and DNA markers linked to resistance traits. Aflatoxin Elimination Workshop, St. Louis, Abstract.
|
Progress 01/01/97 to 12/31/97
Outputs
The norsolorinic acid producing (nor) Aspergillus parasiticus mutant has the aflatoxin pathway partially blocked. This mutant produces nor in corn kernels as well as aflatoxin and thus is useful for visual observations. The initial studies were to determine if the pigment could be used to identify highly susceptible genotypes. The subsequent studies were to evaluate the mutant and wild type A. flavus isolates in studies on invasion of the ear. 1) The mutant was shown to be useful in separating highly susceptible genotypes from those which might be resistant to aflatoxin contamination. 2) In wounded ears, there was a negative correlation between the mutant and the wild type A. flavus. However silk inoculation by the mutant was not effective. There was also a negative correlation between A. flavus and Fusarium moniliforme. 3) The percentage of red kernels observed varied by year and seemed to be related to weather conditions. 4) The occurrence of red kernels was less in
years with high wild A. flavus populations in the ear. 5) The recovery of the mutant was not related to the wound site. The mutant successfully colonized the ear whenever the inoculum was introduced by wounding. These studies have been useful in describing the distribution of the fungi on the ear and the mutant could easily be used to help in a screening program.
Impacts
(N/A)
Publications
- HOLBROOK, C.C., WILSON, D.M., and MATHERON, M.E. 1997. Results from screening the core collection for resistance to preharvest aflatoxin contamination. Aflatoxin Elimination Workshop, Memphis.
- WILSON, D.M., BROCK, J.H., and WIDSTROM, N.W. 1997. Studies on the identification of resistance to aflatoxin contamination of corn using an Aspergillus parasiticus mutant. Aflatoxin Elimination Workshop,
- WILSON, D.M., SYDENHAM, E.W., LOMBAERT, G.A., TRUCKSESS, M.W., ABRAMSON, D., and BENNETT, G.A. 1998. Mycotoxin Analytical Techniques. In K. K. Sinha and D. Bhatnagar (eds.) Mycotoxins in Agriculture and Food Safety. Marcel Dekker, NY (In Press).
- BROCK, J.H. 1997. Comparison of preharvest aflatoxin contamination of a resistant and a susceptible corn genotype. Univ. of GA, M.S.
- ANDERSON, W.F., HOLBROOK, C.C., and WILSON, D.M. 1996. Development of greenhouse screening for resistance to Aspergillus parasiticus infection and aflatoxin contamination in peanut. Mycopathologia
- HOLBROOK, C.C., WILSON, D.M., MATHERON, M.E., and ANDERSON, W.F. 1997. Aspergillus colonization and aflatoxin contamination in peanut genotypes with resistance to other fungal pathogens. Plant Dis.
- PADGETT, G.B., WILSON, D., BEASLEY, J.P., and BALDWIN, J.A. 1997. Preventing aflatoxin in farmer stock peanuts. Leaflet 446, Cooperative Extension Service, The University of Georgia, College of
- BRENNEMAN, T.B., WILSON, D.M., and SHOKES, F.M. 1997. Effects of corn meal as a soil amendment on southern stem rot, aflatoxin production, and Aspergillus populations. Proc. Am. Peanut Res. Edu. Soc., San
|
Progress 01/01/96 to 12/30/96
Outputs
The norsolorinic acid (NOR) producing A. parasiticus mutant (ATTC 24690) has been used for the last three years to develop a screening method for resistance to preharvest aflatoxin contamination of corn. When corn is infected by this mutant it produces NOR and aflatoxin. The NOR can be visually observed. In 1994 and 1995 there was a significant correlation between aflatoxin content and number of red kernels; in 1996, this was not observed. Forty days after full silk very few red kernels were observed, but by harvest the NOR had accumulated and red kernels were observable. The two hybrid test using F 4507A as the susceptible hybrid and MP313ExMAS:gk as the moderately resistant hybrid was designed to find if the differences in red kernels and aflatoxin would be repeatable over years. In 1994, there was a significant difference in red kernels and aflatoxin content between hybrids. In 1995 and 1996 the differences were consistent but not significantly different. The
incidence of natural A. flavus group seemed to interact and influence the incidence of A. parasiticus and red kernels. There was a negative correlation between the incidence of A. flavus group and A. parasiticus. Weather seems to be an important determinant in all aflatoxin studies. Interpretation of our results suggests that weather influences not only the host plant but the native microflora.
Impacts
(N/A)
Publications
- Anderson, W.F., C.C. Holbrook, D.M. Wilson, and M.E. Matheron. 1995. Evaluation of preharvest aflatoxin contamination in several potentially resistant peanut genotypes. Peanut Science 22:29-32.
- Widstrom, N.W., M.J. Forster, W.K. Martin, and D.M. Wilson. 1996. Agronomic performance in the southeastern United States of maize hybrids containing tropical germplasm. Maydica 41:59-63.
- Lynch, R.E., D.M. Wilson, A.P. Ouerdraogo, and I.O. Dicko. 1996. Aflatoxin contamination in peanuts: the role of insects in enhancing contamination. PAEMS Conference on Risk Assessment of Environmental Mutagens and Carcinogens. Cape Town,
- S Wilson, D.M. and N.W. Widstrom. 1996. Use of a norsolorinic acid producing Aspergillus parasiticus mutant to identify resistance to preharvest aflatoxin contamination in corn. PAEMS Conference on Risk Assessment of Environmental Mutagens an
- Wilson, D.M., C.C. Holbrook, and M.E. Matheron. 1996. Aspergillus flavus and A. parasiticus used as peanut plot inoculum to study preharvest aflatoxin contamination. Proc. Am. Peanut Educ. Res., Orlando, FL, abstract.
- Widstrom, N.W. and D.M. Wilson. 1996. Screening for resistance in corn to aflatoxin contamination using a Aspergillus parasiticus mutant. Aflatoxin Elimination Workshop, Fresno, CA, abstract.
|
|