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Aoun M, Siegel C, Windham G, Williams W, Nelson R. Application of reflectance spectroscopy to identify maize genotypes and aflatoxin levels in single kernels. WORLD MYCOTOXIN J 2022. [DOI: 10.3920/wmj2021.2750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Spectroscopy is a rapid, non-destructive, and low-cost analytical technique that has the potential to complement more resource-intensive analytical methods. We explored the use of spectral methods to differentiate maize genotypes and assess aflatoxin (AF) contamination in maize kernels. We compared the performance of two instruments: a research-grade ultraviolet-visible-near infrared (UV-Vis-NIR) spectrometer that measures reflectance from 304 -1,085 nm, and a miniaturised NIR spectrometer that measures reflectance from 740-1,070 nm. Both systems were used to predict AF levels in maize kernels from a single genotype and across 10 genotypes, and to predict genotype for the latter. A partial least square discriminant analysis model was trained on 70% of the kernels and tested on the remaining 30%. The classification accuracy for 10 maize genotypes was 71-72% using the UV-Vis-NIR instrument on 1,170 kernels, and 65-66% using the NIR device on 740 kernels. The classification accuracy for 247 AF-contaminated kernels of a single genotype using the UV-Vis-NIR instrument was 71, 82, and 92% for AF thresholds of 20, 100, and 1000 μg/kg, respectively. Using the same spectrometer on 872 kernels from 10 genotypes, AF classification accuracy was 67, 90, and 95% in validation sets for AF thresholds of 20, 100, and 1000 μg/kg, respectively. The UV-Vis-NIR instrument and the NIR device had similar classification accuracies for AF thresholds of 100 and 1000 μg/kg, whereas the NIR device had higher accuracy for the AF threshold of 20 μg/kg. Reflectance spectroscopy outperformed visual sorting and the bright greenish yellow fluorescence test in identifying AF levels. Applying spectral analysis to estimate mycotoxin levels and to identify maize genotypes could contribute to regional toxin surveillance and action efforts. Further, using AF-associated spectral features for grain sorting can reduce AF exposure.
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Affiliation(s)
- M. Aoun
- School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - C. Siegel
- School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - G.L. Windham
- USDA, Agricultural Research Service, Corn Host Plant Resistance Research Unit, Mississippi State, MS 39762, USA
| | - W.P. Williams
- USDA, Agricultural Research Service, Corn Host Plant Resistance Research Unit, Mississippi State, MS 39762, USA
| | - R.J. Nelson
- School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
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Acharya J, Moorman TB, Kaspar TC, Lenssen AW, Robertson AE. Cover Crop Rotation Effects on Growth and Development, Seedling Disease, and Yield of Corn and Soybean. PLANT DISEASE 2020; 104:677-687. [PMID: 31958247 DOI: 10.1094/pdis-09-19-1904-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The effects of winter cover crops on root disease and growth of corn and soybeans are poorly understood. A 3-year field experiment investigated the effect of winter cereal rye (Secale cereale L.) and winter camelina (Camelina sativa [L.] Crantz), used either in all three years or in rotation with each other, on corn (Zea mays L.) and soybean (Glycine max. [L.] Merr.) growth, root disease, and yield. Corn following a cover crop of camelina had reduced root disease, a lower Pythium population in seedling roots, and greater growth and yields compared with corn following a rye cover crop. Camelina and rye cover crops before soybean had either a positive or no effect on soybean growth and development, root disease, and yield. Moreover, Pythium clade B populations were greater in corn seedlings after a rye cover crop compared with those following a camelina cover crop, whereas clade F populations were greater on soybean seedlings following a camelina cover crop compared with seedlings following a rye cover crop. A winter camelina cover crop grown before corn had less-negative effects on corn seedling growth, root disease, and final yield than a winter rye cover crop before corn. Neither cover crop had negative effects on soybean, and the cover crop in the preceding spring had no measurable effects on either corn or soybean.
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Affiliation(s)
- Jyotsna Acharya
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011
| | - Thomas B Moorman
- National Laboratory for Agriculture and the Environment, USDA ARS, Ames, IA 50011
| | - Thomas C Kaspar
- National Laboratory for Agriculture and the Environment, USDA ARS, Ames, IA 50011
| | | | - Alison E Robertson
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011
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Mitema A, Okoth S, Rafudeen SM. The Development of a qPCR Assay to Measure Aspergillus flavus Biomass in Maize and the Use of a Biocontrol Strategy to Limit Aflatoxin Production. Toxins (Basel) 2019; 11:toxins11030179. [PMID: 30934573 PMCID: PMC6468655 DOI: 10.3390/toxins11030179] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 03/14/2019] [Accepted: 03/18/2019] [Indexed: 01/10/2023] Open
Abstract
Aspergillus flavus colonisation of maize can produce mycotoxins that are detrimental to both human and animal health. Screening of maize lines, resistant to A. flavus infection, together with a biocontrol strategy, could help minimize subsequent aflatoxin contamination. We developed a qPCR assay to measure A. flavus biomass and showed that two African maize lines, GAF4 and KDV1, had different fungal loads for the aflatoxigenic isolate (KSM014), fourteen days after infection. The qPCR assay revealed no significant variation in A. flavus biomass between diseased and non-diseased maize tissues for GAF4, while KDV1 had a significantly higher A. flavus biomass (p < 0.05) in infected shoots and roots compared to the control. The biocontrol strategy using an atoxigenic isolate (KSM012) against the toxigenic isolate (KSM014), showed aflatoxin production inhibition at the co-infection ratio, 50:50 for both maize lines (KDV1 > 99.7% and GAF ≥ 69.4%), as confirmed by bioanalytical techniques. As far as we are aware, this is the first report in Kenya where the biomass of A. flavus from maize tissue was detected and quantified using a qPCR assay. Our results suggest that maize lines, which have adequate resistance to A. flavus, together with the appropriate biocontrol strategy, could limit outbreaks of aflatoxicoses.
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Affiliation(s)
- Alfred Mitema
- Plant Stress Laboratory 204/207, Department of Molecular and Cell Biology, MCB Building, Upper Campus, University of Cape Town, Private bag X3, Rondebosch, Cape Town 7701, South Africa.
- Department of Botany, School of Biological Sciences, University of Nairobi, P.O. Box 30197, Nairobi 00100, Kenya.
| | - Sheila Okoth
- Department of Botany, School of Biological Sciences, University of Nairobi, P.O. Box 30197, Nairobi 00100, Kenya.
| | - Suhail M Rafudeen
- Plant Stress Laboratory 204/207, Department of Molecular and Cell Biology, MCB Building, Upper Campus, University of Cape Town, Private bag X3, Rondebosch, Cape Town 7701, South Africa.
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Suwarno WB, Hannok P, Palacios-Rojas N, Windham G, Crossa J, Pixley KV. Provitamin A Carotenoids in Grain Reduce Aflatoxin Contamination of Maize While Combating Vitamin A Deficiency. FRONTIERS IN PLANT SCIENCE 2019; 10:30. [PMID: 30778360 PMCID: PMC6369730 DOI: 10.3389/fpls.2019.00030] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 01/09/2019] [Indexed: 05/25/2023]
Abstract
Aflatoxin contamination of maize grain and products causes serious health problems for consumers worldwide, and especially in low- and middle-income countries where monitoring and safety standards are inconsistently implemented. Vitamin A deficiency (VAD) also compromises the health of millions of maize consumers in several regions of the world including large parts of sub-Saharan Africa. We investigated whether provitamin A (proVA) enriched maize can simultaneously contribute to alleviate both of these health concerns. We studied aflatoxin accumulation in grain of 120 maize hybrids formed by crossing 3 Aspergillus flavus resistant and three susceptible lines with 20 orange maize lines with low to high carotenoids concentrations. The hybrids were grown in replicated, artificially-inoculated field trials at five environments. Grain of hybrids with larger concentrations of beta-carotene (BC), beta-cryptoxanthin (BCX) and total proVA had significantly less aflatoxin contamination than hybrids with lower carotenoids concentrations. Aflatoxin contamination had negative genetic correlation with BCX (-0.28, p < 0.01), BC (-0.18, p < 0.05), and proVA (-0.23, p < 0.05). The relative ease of breeding for increased proVA carotenoid concentrations as compared to breeding for aflatoxin resistance in maize suggests using the former as a component of strategies to combat aflatoxin contamination problems for maize. Our findings indicate that proVA enriched maize can be particularly beneficial where the health burdens of exposure to aflatoxin and prevalence of VAD converge with high rates of maize consumption.
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Affiliation(s)
- Willy B. Suwarno
- International Maize and Wheat Improvement Center, Texcoco, Mexico
- Department of Agronomy and Horticulture, Faculty of Agriculture, Bogor Agricultural University, Bogor, Indonesia
| | - Pattama Hannok
- International Maize and Wheat Improvement Center, Texcoco, Mexico
- Department of Agronomy, University of Wisconsin-Madison, Madison, WI, United States
| | | | - Gary Windham
- Corn Host Plant Resistance Research Unit, United States Department of Agriculture-Agricultural Research Service, Starkville, MS, United States
| | - José Crossa
- International Maize and Wheat Improvement Center, Texcoco, Mexico
| | - Kevin V. Pixley
- International Maize and Wheat Improvement Center, Texcoco, Mexico
- Department of Agronomy, University of Wisconsin-Madison, Madison, WI, United States
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Curcumin-based photosensitization inactivates Aspergillus flavus and reduces aflatoxin B1 in maize kernels. Food Microbiol 2018; 82:82-88. [PMID: 31027823 DOI: 10.1016/j.fm.2018.12.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 12/15/2018] [Accepted: 12/22/2018] [Indexed: 01/25/2023]
Abstract
Different methods have been applied in controlling contamination of foods and feeds by the carcinogenic fungal toxin, aflatoxin, but nevertheless the problem remains pervasive in developing countries. Curcumin is a natural polyphenolic compound from the spice turmeric (Curcuma longa L.) that has been identified as an efficient photosensitiser for inactivation of Aspergillus flavus conidia. Curcumin mediated photoinactivation of A. flavus has revealed the potential of this technology to be an effective method for reducing population density of the aflatoxin-producing fungus in foods. This study demonstrates the influence of pH and temperature on efficiency of photoinactivation of the fungus and how treating spore-contaminated maize kernels affects aflatoxin production. The results show the efficiency of curcumin mediated photoinactivation of fungal conidia and hyphae were not affected by temperatures between 15 and 35 °C or pH range of 1.5-9.0. The production of aflatoxin B1 was significantly lower (p < 0.05), with an average of 82.4 μg/kg as compared to up to 305.9 μg/kg observed in untreated maize kept under similar conditions. The results of this study indicate that curcumin mediated photosensitization can potentially be applied under simple environmental conditions to achieve significant reduction of post-harvest contamination of aflatoxin B1 in maize.
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Garrido-Bazan V, Mahuku G, Bibbins-Martinez M, Arroyo-Bacerra A, Villalobos-López MÁ. Dissection of mechanisms of resistance to Aspergillus flavus and aflatoxin using tropical maize germplasm. WORLD MYCOTOXIN J 2018. [DOI: 10.3920/wmj2017.2219] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Aspergillus flavus induced ear rots and subsequent contamination of maize (Zea mays L.) by aflatoxin is a serious food safety issue, especially in developing countries where the crop is mostly cultivated by smallholder famers for own consumption and income generation. A better understanding of the mechanisms of resistance could help breeders to develop resistant maize varieties. In this study, a set of six tropical maize inbred lines previously identified as resistant or susceptible under natural field conditions were evaluated for response to A. flavus colonisation and aflatoxin contamination. Fungal biomass was significantly higher (P<0.05) in susceptible than resistant maize inbred lines, and this was highly correlated (P=0.001) to aflatoxin levels. Maize inbred lines MRI, MR2 and MR3 had low fungal biomass and low aflatoxin levels, suggesting that resistance in these lines was mediated through restricted fungal colonisation and establishment. Among the three putatively resistant inbred lines mentioned above, MR2 had a relatively high colonisation compared to the other two lines, revealing that A. flavus could establish and colonise kernels that were injured during inoculation, but did not contain high levels of aflatoxin. This could signify the presence of host genes that interfere with the aflatoxin biosynthetic pathway.
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Affiliation(s)
- V. Garrido-Bazan
- Instituto Politécnico Nacional (IPN), Centro de Investigación en Biotecnología Aplicada, Carretera Estatal Santa Inés Tecuexcomac-Tepetitla Km 1.5, Tlaxcala C.P. 90700, México
- International Maize and Wheat Improvement Center (CIMMYT), Apdo. Postal 6-641, 06600 México D.F., México
| | - G. Mahuku
- International Maize and Wheat Improvement Center (CIMMYT), Apdo. Postal 6-641, 06600 México D.F., México
- International Institute of Tropical Agriculture (IITA), P.O. Box 34441, Dar es Salaam, Tanzania
| | - M. Bibbins-Martinez
- Instituto Politécnico Nacional (IPN), Centro de Investigación en Biotecnología Aplicada, Carretera Estatal Santa Inés Tecuexcomac-Tepetitla Km 1.5, Tlaxcala C.P. 90700, México
| | - A. Arroyo-Bacerra
- Instituto Politécnico Nacional (IPN), Centro de Investigación en Biotecnología Aplicada, Carretera Estatal Santa Inés Tecuexcomac-Tepetitla Km 1.5, Tlaxcala C.P. 90700, México
| | - M. Ángel Villalobos-López
- Instituto Politécnico Nacional (IPN), Centro de Investigación en Biotecnología Aplicada, Carretera Estatal Santa Inés Tecuexcomac-Tepetitla Km 1.5, Tlaxcala C.P. 90700, México
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LAMP-based group specific detection of aflatoxin producers within Aspergillus section Flavi in food raw materials, spices, and dried fruit using neutral red for visible-light signal detection. Int J Food Microbiol 2017; 266:241-250. [PMID: 29272724 DOI: 10.1016/j.ijfoodmicro.2017.12.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 12/13/2017] [Accepted: 12/14/2017] [Indexed: 01/10/2023]
Abstract
Aflatoxins can be produced by 21 species within sections Flavi (16 species), Ochraceorosei (2), and Nidulantes (3) of the fungal genus Aspergillus. They pose risks to human and animal health due to high toxicity and carcinogenicity. Detecting aflatoxin producers can help to assess toxicological risks associated with contaminated commodities. Species specific molecular assays (PCR and LAMP) are available for detection of major producers, but fail to detect species of minor importance. To enable rapid and sensitive detection of several aflatoxin producing species in a single analysis, a nor1 gene-specific LAMP assay was developed. Specificity testing showed that among 128 fungal species from 28 genera, 15 aflatoxigenic species in section Flavi were detected, including synonyms of A. flavus and A. parasiticus. No cross reactions were found with other tested species. The detection limit of the assay was 9.03pg of A. parasiticus genomic DNA per reaction. Visual detection of positive LAMP reactions under daylight conditions was facilitated using neutral red to allow unambiguous distinction between positive and negative assay results. Application of the assay to the detection of A. parasiticus conidia revealed a detection limit of 211 conidia per reaction after minimal sample preparation. The usefulness of the assay was demonstrated in the analysis of aflatoxinogenic species in samples of rice, nuts, raisins, dried figs, as well as powdered spices. Comparison of LAMP results with presence/absence of aflatoxins and aflatoxin producing fungi in 50 rice samples showed good correlation between these parameters. Our study suggests that the developed LAMP assay is a rapid, sensitive and user-friendly tool for surveillance and quality control in our food industry.
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Acharya J, Bakker MG, Moorman TB, Kaspar TC, Lenssen AW, Robertson AE. Time Interval Between Cover Crop Termination and Planting Influences Corn Seedling Disease, Plant Growth, and Yield. PLANT DISEASE 2017; 101:591-600. [PMID: 30677366 DOI: 10.1094/pdis-07-16-0975-re] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Experiments were established in a controlled-growth chamber and in the field to evaluate the effect of the length of time intervals between winter rye cover crop termination and corn planting on corn seedling disease, corn growth, and grain yield in 2014 and 2015. Rye termination dates ranged from 25 days before planting (DBP) to 2 days after planting (DAP) corn in the field and from 21 DBP to 1 DAP in controlled studies. Results were similar in both environments. In general, shorter intervals increased seedling disease and reduced corn emergence, shoot growth, and grain yield of corn following winter rye compared with corn planted 10 or more days after rye termination or without rye. Incidence of Pythium spp. increased with shorter intervals (less than 8 DBP); incidence of Fusarium spp. was not consistent between runs and experiments. In 2014, in the 1-DAP treatment, number of ears and grain yield were reduced (P = 0.05 and 0.02, respectively). In 2015, all termination intervals reduced plant population, number of ears, and yield (P = 0.01), with the 2-DBP treatment causing the biggest decrease. A 10- to 14-day interval between rye termination and corn planting should be followed to improve corn yield following a rye cover crop.
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Affiliation(s)
- J Acharya
- Department of Plant Pathology and Microbiology, Iowa State University, Ames 50011
| | - M G Bakker
- National Laboratory for Agriculture and the Environment, United States Department of Agriculture-Agricultural Research Service, Ames, IA 50011
| | - T B Moorman
- National Laboratory for Agriculture and the Environment, United States Department of Agriculture-Agricultural Research Service, Ames, IA 50011
| | - T C Kaspar
- National Laboratory for Agriculture and the Environment, United States Department of Agriculture-Agricultural Research Service, Ames, IA 50011
| | - A W Lenssen
- Department of Agronomy, Iowa State University, Ames
| | - A E Robertson
- Department of Plant Pathology and Microbiology, Iowa State University, Ames
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Bakker MG, Acharya J, Moorman TB, Robertson AE, Kaspar TC. The Potential for Cereal Rye Cover Crops to Host Corn Seedling Pathogens. PHYTOPATHOLOGY 2016; 106:591-601. [PMID: 26926485 DOI: 10.1094/phyto-09-15-0214-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Cover cropping is a prevalent conservation practice that offers substantial benefits to soil and water quality. However, winter cereal cover crops preceding corn may diminish beneficial rotation effects because two grass species are grown in succession. Here, we show that rye cover crops host pathogens capable of causing corn seedling disease. We isolated Fusarium graminearum, F. oxysporum, Pythium sylvaticum, and P. torulosum from roots of rye and demonstrate their pathogenicity on corn seedlings. Over 2 years, we quantified the densities of these organisms in rye roots from several field experiments and at various intervals of time after rye cover crops were terminated. Pathogen load in rye roots differed among fields and among years for particular fields. Each of the four pathogen species increased in density over time on roots of herbicide-terminated rye in at least one field site, suggesting the broad potential for rye cover crops to elevate corn seedling pathogen densities. The radicles of corn seedlings planted following a rye cover crop had higher pathogen densities compared with seedlings following a winter fallow. Management practices that limit seedling disease may be required to allow corn yields to respond positively to improvements in soil quality brought about by cover cropping.
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Affiliation(s)
- Matthew G Bakker
- First, third, and fifth authors: United States Department of Agriculture-Agricultural Research Service, National Laboratory for Agriculture and the Environment, 1015 N University Blvd, Ames, IA 50011; and second and fourth authors: Iowa State University, Department of Plant Pathology and Microbiology, 351 Bessey Hall, Ames 50011
| | - Jyotsna Acharya
- First, third, and fifth authors: United States Department of Agriculture-Agricultural Research Service, National Laboratory for Agriculture and the Environment, 1015 N University Blvd, Ames, IA 50011; and second and fourth authors: Iowa State University, Department of Plant Pathology and Microbiology, 351 Bessey Hall, Ames 50011
| | - Thomas B Moorman
- First, third, and fifth authors: United States Department of Agriculture-Agricultural Research Service, National Laboratory for Agriculture and the Environment, 1015 N University Blvd, Ames, IA 50011; and second and fourth authors: Iowa State University, Department of Plant Pathology and Microbiology, 351 Bessey Hall, Ames 50011
| | - Alison E Robertson
- First, third, and fifth authors: United States Department of Agriculture-Agricultural Research Service, National Laboratory for Agriculture and the Environment, 1015 N University Blvd, Ames, IA 50011; and second and fourth authors: Iowa State University, Department of Plant Pathology and Microbiology, 351 Bessey Hall, Ames 50011
| | - Thomas C Kaspar
- First, third, and fifth authors: United States Department of Agriculture-Agricultural Research Service, National Laboratory for Agriculture and the Environment, 1015 N University Blvd, Ames, IA 50011; and second and fourth authors: Iowa State University, Department of Plant Pathology and Microbiology, 351 Bessey Hall, Ames 50011
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Mylroie JE, Ozkan S, Shivaji R, Windham GL, Alpe MN, Williams WP. Identification and Quantification of a Toxigenic and Non-Toxigenic Aspergillus flavus Strain in Contaminated Maize Using Quantitative Real-Time PCR. Toxins (Basel) 2016; 8:E15. [PMID: 26742074 PMCID: PMC4728537 DOI: 10.3390/toxins8010015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 12/17/2015] [Accepted: 12/28/2015] [Indexed: 11/16/2022] Open
Abstract
Aflatoxins, which are produced by Aspergillus flavus, are toxic to humans, livestock, and pets. The value of maize (Zea mays) grain is markedly reduced when contaminated with aflatoxin. Plant resistance and biological control using non-toxin producing strains are considered effective strategies for reducing aflatoxin accumulation in maize grain. Distinguishing between the toxin and non-toxin producing strains is important in determining the effectiveness of bio-control strategies and understanding inter-strain interactions. Using polymorphisms found in the fungal rRNA intergenic spacer region (IGS) between a toxigenic strain of A. flavus (NRRL 3357) and the non-toxigenic strain used in the biological control agent Afla-Guard(®) (NRRL 21882), we developed a set of primers that allows for the identification and quantification of the two strains using quantitative PCR. This primer set has been used to screen maize grain that was inoculated with the two strains individually and co-inoculated with both strains, and it has been shown to be effective in both the identification and quantification of both strains. Screening of co-inoculated ears from multiple resistant and susceptible genotypic crosses revealed no significant differences in fungal biomass accumulation of either strain in the field tests from 2010 and 2011 when compared across the means of all genotypes. Only one genotype/year combination showed significant differences in strain accumulation. Aflatoxin accumulation analysis showed that, as expected, genotypes inoculated with the toxigenic strain accumulated more aflatoxin than when co-inoculated with both strains or inoculated with only the non-toxigenic strain. Furthermore, accumulation of toxigenic fungal mass was significantly correlated with aflatoxin accumulation while non-toxigenic fungal accumulation was not. This primer set will allow researchers to better determine how the two fungal strains compete on the maize ear and investigate the interaction between different maize lines and these A. flavus strains.
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Affiliation(s)
- J Erik Mylroie
- United States Department of Agriculture, Agricultural Research Service, Corn Host Plant Resistance Research Unit, Mississippi State City, MS 39762, USA.
| | - Seval Ozkan
- Department of Plant and Soil Sciences, Mississippi State University, Mississippi State City, MS 39762, USA.
| | - Renuka Shivaji
- University of North Carolina at Greensboro Molecular Core Lab, University of North Carolina at Greensboro, Greensboro, NC 27412, USA.
| | - Gary L Windham
- United States Department of Agriculture, Agricultural Research Service, Corn Host Plant Resistance Research Unit, Mississippi State City, MS 39762, USA.
| | - Michael N Alpe
- United States Department of Agriculture, Agricultural Research Service, Corn Host Plant Resistance Research Unit, Mississippi State City, MS 39762, USA.
| | - W Paul Williams
- United States Department of Agriculture, Agricultural Research Service, Corn Host Plant Resistance Research Unit, Mississippi State City, MS 39762, USA.
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Schubert M, Houdelet M, Kogel KH, Fischer R, Schillberg S, Nölke G. Thanatin confers partial resistance against aflatoxigenic fungi in maize (Zea mays). Transgenic Res 2015; 24:885-95. [PMID: 26071308 DOI: 10.1007/s11248-015-9888-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 06/06/2015] [Indexed: 11/28/2022]
Abstract
Aflatoxin-producing fungi can contaminate plants and plant-derived products with carcinogenic secondary metabolites that present a risk to human and animal health. In this study, we investigated the effect of antimicrobial peptides on the major aflatoxigenic fungi Aspergillus flavus and A. parasiticus. In vitro assays with different chemically-synthesized peptides demonstrated that the broad-spectrum peptide thanatin from the spined soldier bug (Podisus maculiventris) had the greatest potential to eliminate aflatoxigenic fungi. The minimal inhibitory concentrations of thanatin against A. flavus and A. parasiticus were 3.13 and 12.5 µM, respectively. A thanatin cDNA was subsequently cloned in a plant expression vector under the control of the ubiquitin-1 promoter allowing the recombinant peptide to be directed to the apoplast in transgenic maize plants. Successful integration of the thanatin expression cassette was confirmed by PCR and expression was demonstrated by semi-quantitative RT-PCR in transgenic maize kernels. Infection assays with maize kernels from T1 transgenic plants showed up to three-fold greater resistance against Aspergillus spp. infections compared to non-transgenic kernels. We demonstrated for the first time that heterologous expression of the antimicrobial peptide thanatin inhibits the growth of Aspergillus spp. in transgenic maize plants offering a solution to protect crops from aflatoxin-producing fungi and the resulting aflatoxin contamination in the field and under storage conditions.
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Affiliation(s)
- Max Schubert
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany
| | - Marcel Houdelet
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany
| | - Karl-Heinz Kogel
- Institute of Phytopathology and Applied Zoology, Justus-Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany
| | - Rainer Fischer
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.,Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany
| | - Stefan Schillberg
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.,Institute of Phytopathology and Applied Zoology, Justus-Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany
| | - Greta Nölke
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.
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Resistance to Aspergillus flavus in maize and peanut: Molecular biology, breeding, environmental stress, and future perspectives. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.cj.2015.02.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Tannous J, Atoui A, El Khoury A, Kantar S, Chdid N, Oswald IP, Puel O, Lteif R. Development of a real-time PCR assay for Penicillium expansum quantification and patulin estimation in apples. Food Microbiol 2015; 50:28-37. [PMID: 25998812 DOI: 10.1016/j.fm.2015.03.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 01/19/2015] [Accepted: 03/02/2015] [Indexed: 10/23/2022]
Abstract
Due to the occurrence and spread of the fungal contaminants in food and the difficulties to remove their resulting mycotoxins, rapid and accurate methods are needed for early detection of these mycotoxigenic fungi. The polymerase chain reaction and the real time PCR have been widely used for this purpose. Apples are suitable substrates for fungal colonization mostly caused by Penicillium expansum, which produces the mycotoxin patulin during fruit infection. This study describes the development of a real-time PCR assay incorporating an internal amplification control (IAC) to specifically detect and quantify P. expansum. A specific primer pair was designed from the patF gene, involved in patulin biosynthesis. The selected primer set showed a high specificity for P. expansum and was successfully employed in a standardized real-time PCR for the direct quantification of this fungus in apples. Using the developed system, twenty eight apples were analyzed for their DNA content. Apples were also analyzed for patulin content by HPLC. Interestingly, a positive correlation (R(2) = 0.701) was found between P. expansum DNA content and patulin concentration. This work offers an alternative to conventional methods of patulin quantification and mycological detection of P. expansum and could be very useful for the screening of patulin in fruits through the application of industrial quality control.
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Affiliation(s)
- Joanna Tannous
- Université Saint-Joseph, Centre d'Analyses et de Recherche (Faculté des Sciences), Campus des Sciences et Technologies, Mar Roukos, Mkallès, P.O Box 11-514, Riad El Solh, 1107 2050 Beirut, Lebanon; INRA, UMR 1331 Toxalim, Research Centre in Food Toxicology, 180 Chemin de Tournefeuille, F-31027 Toulouse, Cedex, France; Université de Toulouse III, ENVT, INP, UMR 1331, Toxalim, F-31076, Toulouse, France
| | - Ali Atoui
- Laboratory of Microorganisms and Food Irradiation, Lebanese Atomic Energy Commission-CNRS, P.O. Box 11-8281, Riad El Solh, 1107 2260 Beirut, Lebanon.
| | - André El Khoury
- Université Saint-Joseph, Centre d'Analyses et de Recherche (Faculté des Sciences), Campus des Sciences et Technologies, Mar Roukos, Mkallès, P.O Box 11-514, Riad El Solh, 1107 2050 Beirut, Lebanon
| | - Sally Kantar
- Université Saint-Joseph, Centre d'Analyses et de Recherche (Faculté des Sciences), Campus des Sciences et Technologies, Mar Roukos, Mkallès, P.O Box 11-514, Riad El Solh, 1107 2050 Beirut, Lebanon
| | - Nader Chdid
- Université Saint-Joseph, Centre d'Analyses et de Recherche (Faculté des Sciences), Campus des Sciences et Technologies, Mar Roukos, Mkallès, P.O Box 11-514, Riad El Solh, 1107 2050 Beirut, Lebanon
| | - Isabelle P Oswald
- INRA, UMR 1331 Toxalim, Research Centre in Food Toxicology, 180 Chemin de Tournefeuille, F-31027 Toulouse, Cedex, France; Université de Toulouse III, ENVT, INP, UMR 1331, Toxalim, F-31076, Toulouse, France
| | - Olivier Puel
- INRA, UMR 1331 Toxalim, Research Centre in Food Toxicology, 180 Chemin de Tournefeuille, F-31027 Toulouse, Cedex, France; Université de Toulouse III, ENVT, INP, UMR 1331, Toxalim, F-31076, Toulouse, France
| | - Roger Lteif
- Université Saint-Joseph, Centre d'Analyses et de Recherche (Faculté des Sciences), Campus des Sciences et Technologies, Mar Roukos, Mkallès, P.O Box 11-514, Riad El Solh, 1107 2050 Beirut, Lebanon
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Luo J, Vogel RF, Niessen L. Rapid detection of aflatoxin producing fungi in food by real-time quantitative loop-mediated isothermal amplification. Food Microbiol 2014; 44:142-8. [DOI: 10.1016/j.fm.2014.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 04/10/2014] [Accepted: 06/06/2014] [Indexed: 11/30/2022]
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15
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Arquiza JMRA, Hunter J. The use of real-time PCR to study Penicillium chrysogenum growth kinetics on solid food at different water activities. Int J Food Microbiol 2014; 187:50-6. [PMID: 25036772 DOI: 10.1016/j.ijfoodmicro.2014.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 05/17/2014] [Accepted: 06/05/2014] [Indexed: 11/30/2022]
Abstract
Fungal growth on solid foods can make them unfit for human consumption, but certain specialty foods require fungi to produce their characteristic properties. In either case, a reliable way of measuring biomass is needed to study how various factors (e.g. water activity) affect fungal growth rates on these substrates. Biochemical markers such as chitin, glucosamine or ergosterol have been used to estimate fungal growth, but they cannot distinguish between individual species in mixed culture. In this study, a real-time polymerase chain reaction (rt-PCR) protocol specific for a target fungal species was used to quantify its DNA while growing on solid food. The measured amount of DNA was then related to the biomass present using an experimentally determined DNA-to-biomass ratio. The highly sensitive rt-PCR biomass assay was found to have a wide range, able to quantify the target DNA within a six orders-of-magnitude difference. The method was used to monitor germination and growth of Penicillium chrysogenum spores on a model porous food (cooked wheat flour) at 25°C and different water activities of 0.973, 0.936, and 0.843. No growth was observed at 0.843, but lag, exponential and stationary phases were identified in the growth curves for the higher water activities. The calculated specific growth rates (μ) during the exponential phase were almost identical, at 0.075/h and 0.076/h for aw=0.973 and 0.936, respectively. The specificity of the method was demonstrated by measuring the biomass of P. chrysogenum while growing together with Aspergillus niger on solid media at aw=0.973.
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Affiliation(s)
- J M R Apollo Arquiza
- Department of Biological & Environmental Engineering, Cornell University, Ithaca, NY, USA
| | - Jean Hunter
- Department of Biological & Environmental Engineering, Cornell University, Ithaca, NY, USA.
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16
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Gusberti M, Patocchi A, Gessler C, Broggini GAL. Quantification of Venturia inaequalis Growth in Malus × domestica with Quantitative Real-Time Polymerase Chain Reaction. PLANT DISEASE 2012; 96:1791-1797. [PMID: 30727262 DOI: 10.1094/pdis-12-11-1058-re] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A quantitative real-time polymerase chain reaction (qPCR) was developed and validated for quantification of Venturia inaequalis in infected leaf tissue of Malus × domestica. The method is based on dual-labeled hybridization probes, allowing simultaneous detection of host and pathogen DNA within one single reaction. Limit of quantification for the pathogen was 0.5 pg per reaction and, for the host, reached 5 pg per reaction. The fungal growth measured in four apple cultivars 2 weeks after inoculation significantly correlated with their different level of scab resistance and allowed the observation of ontogenic resistance. After sporulation on the youngest leaf, fungal biomass in susceptible 'Gala' was 118 times higher than in resistant 'Florina' and 'Discovery' while intermediate values were found with the intermediate susceptible 'Milwa'. Correlation was also observed between severity classes obtained by visual scoring of symptoms and qPCR results. Moreover, qPCR demonstrated validity of the developed method as a disease severity forecast tool 10 days after the pathogen's inoculation and prior to the appearance of the symptoms. Applications of the methodology can include the quantification of scab resistance during breeding programs, evaluation of fungicide and biocontrol efficacy, and quantification of the fitness of different pathogenic strains.
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Affiliation(s)
- Michele Gusberti
- Institute of Integrative Biology Zurich, Plant Pathology Group, Swiss Federal Institute of Technology, CH-8092 Zürich, Switzerland
| | - Andrea Patocchi
- Agroscope Changins Wädenswil ACW Research Station, Schloss, CH-8820 Wädenswil, Switzerland
| | - Cesare Gessler
- Institute of Integrative Biology Zurich, Plant Pathology Group, Swiss Federal Institute of Technology, CH-8092 Zürich, Switzerland
| | - Giovanni A L Broggini
- Institute of Integrative Biology Zurich, Plant Pathology Group, Swiss Federal Institute of Technology, CH-8092 Zürich, Switzerland
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17
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Development and application of a loop-mediated isothermal amplification assay for rapid identification of aflatoxigenic molds and their detection in food samples. Int J Food Microbiol 2012; 159:214-24. [PMID: 23107500 DOI: 10.1016/j.ijfoodmicro.2012.08.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 08/24/2012] [Accepted: 08/28/2012] [Indexed: 11/21/2022]
Abstract
Aflatoxins are the most thoroughly studied mycotoxins. They are produced by several members of the genus Aspergillus in section Flavi with Aspergillus flavus, Aspergillus parasiticus, and Aspergillus nomius being frequently isolated from contaminated food sources. In this work, we describe the development and evaluation of loop-mediated isothermal amplification (LAMP) assays for rapid detection of the three species in separate analyses. The acl1-gene of A. flavus and amy1-genes of A. nomius and A. parasiticus were used as target genes. The detection limits were 2.4, 7.6 and 20pg of pure DNA/reaction for A. flavus, A. nomius and A. parasiticus, respectively. For specificity testing, DNA extracted from mycelia of representative strains of 39 Aspergillus species, 23 Penicillium species, 75 Fusarium species and 37 other fungal species was used as a template for the specific LAMP primer sets developed for the three target species. The LAMP assay was combined with a DNA extraction method for the analysis of pure fungal cultures as well as artificially contaminated Brazil nuts, peanuts and green coffee beans. It is suggested that the developed LAMP assay is a promising tool in the prediction of a potential aflatoxin risk in food and food raw materials and may therefore be suitable for high throughput analysis in the food industry.
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Mideros SX, Windham GL, Williams WP, Nelson RJ. Tissue-specific components of resistance to Aspergillus ear rot of maize. PHYTOPATHOLOGY 2012; 102:787-793. [PMID: 22779745 DOI: 10.1094/phyto-12-11-0355] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Aspergillus flavus and other Aspergillus spp. infect maize and produce aflatoxins. An important control measure is the use of resistant maize hybrids. There are several reports of maize lines that are resistant to aflatoxin accumulation but the mechanisms of resistance remain unknown. To gain a better understanding of resistance, we dissected the phenotype into 10 components: 4 pertaining to the response of silk, 4 pertaining to the response of developing kernels, and 2 pertaining to the response of mature kernels to inoculation with A. flavus. In order to challenge different tissues and to evaluate multiple components of resistance, various inoculation methods were used in experiments in vitro and under field conditions on a panel of diverse maize inbred lines over 3 years. As is typical for this trait, significant genotype-environment interactions were found for all the components of resistance studied. There was, however, significant variation in maize germplasm for susceptibility to silk and kernel colonization by A. flavus as measured in field assays. Resistance to silk colonization has not previously been reported. A significant correlation of resistance to aflatoxin accumulation with flowering time and kernel composition traits (fiber, ash, carbohydrate, and seed weight) was detected. In addition, correlation analyses with data available in the literature indicated that lines that flower later in the season tend to be more resistant. We were not able to demonstrate that components identified in vitro were associated with reduced aflatoxin accumulation in the field.
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Affiliation(s)
- Santiago X Mideros
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
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Validation of RT-qPCR reference genes for in planta expression studies in Hemileia vastatrix, the causal agent of coffee leaf rust. Fungal Biol 2011; 115:891-901. [PMID: 21872186 DOI: 10.1016/j.funbio.2011.07.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 06/30/2011] [Accepted: 07/04/2011] [Indexed: 01/08/2023]
Abstract
Hemileia vastatrix is a biotrophic fungus, causing coffee leaf rust in all coffee growing countries, leading to serious social and economic problems. Gene expression studies may have a key role unravelling the transcriptomics of this pathogen during interaction with the plant host. Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) is currently the golden standard for gene expression analysis, although an accurate normalisation is essential for adequate conclusions. Reference genes are often used for this purpose, but the stability of their expression levels requires validation under experimental conditions. Moreover, pathogenic fungi undergo important biomass variations along their infection process in planta, which raises the need for an adequate method to further normalise the proportion of fungal cDNA in the total plant and fungus cDNA pool. In this work, the expression profiles of seven reference genes [glyceraldehyde-3-phosphate dehydrogenase (GADPH), elongation factor (EF-1), Beta tubulin (β-tubulin), cytochrome c oxidase subunit III (Cyt III), cytochrome b (Cyt b), Hv00099, and 40S ribosomal protein (40S_Rib)] were analysed across 28 samples, obtained in vitro (germinated uredospores and appressoria) and in planta (post-penetration fungal growth phases). Gene stability was assessed using the statistical algorithms incorporated in geNorm and NormFinder tools. Cyt b, 40S_Rib, and Hv00099 were the most stable genes for the in vitro dataset, while 40S_Rib, GADPH, and Cyt III were the most stable in planta. For the combined datasets (in vitro and in planta), 40S_Rib, GADPH, and Hv00099 were selected as the most stable. Subsequent expression analysis for a gene encoding an alpha subunit of a heterotrimeric G-protein showed that the reference genes selected for the combined dataset do not differ significantly from those selected specifically for the in vitro and in planta datasets. Our study provides tools for correct validation of reference genes in obligate biotrophic plant pathogens, as well as the basis for RT-qPCR studies in H. vastatrix.
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Warburton ML, Williams WP, Hawkins L, Bridges S, Gresham C, Harper J, Ozkan S, Mylroie JE, Shan X. A public platform for the verification of the phenotypic effect of candidate genes for resistance to aflatoxin accumulation and Aspergillus flavus infection in maize. Toxins (Basel) 2011; 3:754-65. [PMID: 22069738 PMCID: PMC3202859 DOI: 10.3390/toxins3070754] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Revised: 06/10/2011] [Accepted: 06/15/2011] [Indexed: 12/03/2022] Open
Abstract
A public candidate gene testing pipeline for resistance to aflatoxin accumulation or Aspergillus flavus infection in maize is presented here. The pipeline consists of steps for identifying, testing, and verifying the association of selected maize gene sequences with resistance under field conditions. Resources include a database of genetic and protein sequences associated with the reduction in aflatoxin contamination from previous studies; eight diverse inbred maize lines for polymorphism identification within any maize gene sequence; four Quantitative Trait Loci (QTL) mapping populations and one association mapping panel, all phenotyped for aflatoxin accumulation resistance and associated phenotypes; and capacity for Insertion/Deletion (InDel) and SNP genotyping in the population(s) for mapping. To date, ten genes have been identified as possible candidate genes and put through the candidate gene testing pipeline, and results are presented here to demonstrate the utility of the pipeline.
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Affiliation(s)
- Marilyn L. Warburton
- Corn Host Plant Resistance Research Unit, U.S. Department of Agriculture-Agricultural Research Service, MS 39762, USA; (W.P.W.); (L.H.)
| | - William Paul Williams
- Corn Host Plant Resistance Research Unit, U.S. Department of Agriculture-Agricultural Research Service, MS 39762, USA; (W.P.W.); (L.H.)
| | - Leigh Hawkins
- Corn Host Plant Resistance Research Unit, U.S. Department of Agriculture-Agricultural Research Service, MS 39762, USA; (W.P.W.); (L.H.)
| | - Susan Bridges
- Department of Computer Science and Engineering, Mississippi State University, MS 39762, USA; (S.B.); (C.G.); (J.H.)
| | - Cathy Gresham
- Department of Computer Science and Engineering, Mississippi State University, MS 39762, USA; (S.B.); (C.G.); (J.H.)
| | - Jonathan Harper
- Department of Computer Science and Engineering, Mississippi State University, MS 39762, USA; (S.B.); (C.G.); (J.H.)
| | - Seval Ozkan
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, MS 39762, USA; (S.O.); (J.E.M.); (X.S.)
| | - J. Erik Mylroie
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, MS 39762, USA; (S.O.); (J.E.M.); (X.S.)
| | - Xueyan Shan
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, MS 39762, USA; (S.O.); (J.E.M.); (X.S.)
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Chung CL, Poland J, Kump K, Benson J, Longfellow J, Walsh E, Balint-Kurti P, Nelson R. Targeted discovery of quantitative trait loci for resistance to northern leaf blight and other diseases of maize. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2011; 123:307-26. [PMID: 21526397 DOI: 10.1007/s00122-011-1585-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Accepted: 03/24/2011] [Indexed: 05/02/2023]
Abstract
To capture diverse alleles at a set of loci associated with disease resistance in maize, heterogeneous inbred family (HIF) analysis was applied for targeted QTL mapping and near-isogenic line (NIL) development. Tropical maize lines CML52 and DK888 were chosen as donors of alleles based on their known resistance to multiple diseases. Chromosomal regions ("bins"; n = 39) associated with multiple disease resistance (MDR) were targeted based on a consensus map of disease QTLs in maize. We generated HIFs segregating for the targeted loci but isogenic at ~97% of the genome. To test the hypothesis that CML52 and DK888 alleles at MDR hotspots condition broad-spectrum resistance, HIFs and derived NILs were tested for resistance to northern leaf blight (NLB), southern leaf blight (SLB), gray leaf spot (GLS), anthracnose leaf blight (ALB), anthracnose stalk rot (ASR), common rust, common smut, and Stewart's wilt. Four NLB QTLs, two ASR QTLs, and one Stewart's wilt QTL were identified. In parallel, a population of 196 recombinant inbred lines (RILs) derived from B73 × CML52 was evaluated for resistance to NLB, GLS, SLB, and ASR. The QTLs mapped (four for NLB, five for SLB, two for GLS, and two for ASR) mostly corresponded to those found using the NILs. Combining HIF- and RIL-based analyses, we discovered two disease QTLs at which CML52 alleles were favorable for more than one disease. A QTL in bin 1.06-1.07 conferred resistance to NLB and Stewart's wilt, and a QTL in 6.05 conferred resistance to NLB and ASR.
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Affiliation(s)
- Chia-Lin Chung
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY14853, USA
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Henry WB, Krakowsky MD, Windham GL, Williams WP, Scully BT, Rowe D, Hawkins LK. Comparison of the side-needle and knife techniques for inducingAspergillus flavusinfection and aflatoxin accumulation in corn hybrids. TOXIN REV 2010. [DOI: 10.3109/15569543.2010.517616] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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