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Ouadhene MA, Callicott KA, Ortega‐Beltran A, Mehl HL, Cotty PJ, Battilani P. Structure of Aspergillus flavus populations associated with maize in Greece, Spain, and Serbia: Implications for aflatoxin biocontrol on a regional scale. ENVIRONMENTAL MICROBIOLOGY REPORTS 2024; 16:e13249. [PMID: 38634243 PMCID: PMC11024511 DOI: 10.1111/1758-2229.13249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 03/12/2024] [Indexed: 04/19/2024]
Abstract
Aspergillus flavus is the most frequently identified producer of aflatoxins. Non-aflatoxigenic members of the A. flavus L strains are used in various continents as active ingredients of bioprotectants directed at preventing aflatoxin contamination by competitive displacement of aflatoxin producers. The current research examined the genetic diversity of A. flavus L strain across southern Europe to gain insights into the population structure and evolution of this species and to evaluate the prevalence of genotypes closely related to MUCL54911, the active ingredient of AF-X1. A total of 2173L strain isolates recovered from maize collected across Greece, Spain, and Serbia in 2020 and 2021 were subjected to simple sequence repeat (SSR) genotyping. The analysis revealed high diversity within and among countries and dozens of haplotypes shared. Linkage disequilibrium analysis indicated asexual reproduction and clonal evolution of A. flavus L strain resident in Europe. Moreover, haplotypes closely related to MUCL54911 were found to belong to the same vegetative compatibility group (VCG) IT006 and were relatively common in all three countries. The results indicate that IT006 is endemic to southern Europe and may be utilized as an aflatoxin mitigation tool for maize across the region without concern for potential adverse impacts associated with the introduction of an exotic microorganism.
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Affiliation(s)
- Mohamed Ali Ouadhene
- Department of Sustainable Crop ProductionUniversità Cattolica del Sacro CuorePiacenzaItaly
| | | | | | | | - Peter J. Cotty
- College of Food Science and EngineeringOcean University of ChinaQingdaoChina
| | - Paola Battilani
- Department of Sustainable Crop ProductionUniversità Cattolica del Sacro CuorePiacenzaItaly
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Weaver MA, Bowen C, Park LC, Bastidas A, Drewry SG, Mandel JR. Genetic Diversity of Aspergillus flavus on Maize in Guatemala. Foods 2023; 12:3864. [PMID: 37893757 PMCID: PMC10606850 DOI: 10.3390/foods12203864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 10/06/2023] [Accepted: 10/17/2023] [Indexed: 10/29/2023] Open
Abstract
Aflatoxin contamination of maize is a leading threat to health in Guatemala. This contamination is the result of infection from Aspergillus flavus and has been effectively reduced in other countries through application of nonaflatoxigenic, indigenous strains of A. flavus. We collected 82 maize samples from throughout Guatemala in two years and isolated 272 A. flavus from these samples, including 126 unique genotypes. We provide here a phenotypic and simple sequence repeat (SSR)-based genotypic description of these isolates, as well as an analysis of the diversity of this population. High levels of genetic diversity were observed with the nonaflatoxigenic isolates in this study, but this information contributes to the development of indigenous aflatoxin biocontrol products.
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Affiliation(s)
- Mark A. Weaver
- USDA ARS National Biological Control Laboratory, 59 Lee Road, Stoneville, MS 38776, USA;
| | - Curt Bowen
- Semilla Nueva, 7 Avenida 14-44 Zona 9 Edificio La Galería, Oficina 35 Guatemala, Guatemala City 01009, Guatemala; (C.B.)
| | - Lilly C. Park
- USDA ARS National Biological Control Laboratory, 59 Lee Road, Stoneville, MS 38776, USA;
| | - Angela Bastidas
- Semilla Nueva, 7 Avenida 14-44 Zona 9 Edificio La Galería, Oficina 35 Guatemala, Guatemala City 01009, Guatemala; (C.B.)
| | - Samantha G. Drewry
- Department of Biological Sciences, University of Memphis, 3774 Walker Avenue, Memphis, TN 38152, USA; (S.G.D.); (J.R.M.)
| | - Jennifer R. Mandel
- Department of Biological Sciences, University of Memphis, 3774 Walker Avenue, Memphis, TN 38152, USA; (S.G.D.); (J.R.M.)
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Arreguin-Perez CA, Miranda-Miranda E, Folch-Mallol JL, Cossío-Bayúgar R. Identification of Virulence Factors in Entomopathogenic Aspergillus flavus Isolated from Naturally Infected Rhipicephalus microplus. Microorganisms 2023; 11:2107. [PMID: 37630667 PMCID: PMC10457961 DOI: 10.3390/microorganisms11082107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 08/10/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
Aspergillus flavus has been found to be an effective entomopathogenic fungus for various arthropods, including ticks. In particular, natural fungal infections in cattle ticks show promise for biocontrol of the Rhipicephalus (Boophilus) microplus tick, which is a major ectoparasite affecting cattle worldwide. Our study aimed to elucidate the specific entomopathogenic virulence factors encoded in the genome of an A. flavus strain isolated from naturally infected cattle ticks. We performed morphological and biochemical phenotyping alongside complete genome sequencing, which revealed that the isolated fungus was A. flavus related to the L morphotype, capable of producing a range of gene-coded entomopathogenic virulence factors, including ribotoxin, aflatoxin, kojic acid, chitinases, killer toxin, and satratoxin. To evaluate the efficacy of this A. flavus strain against ticks, we conducted experimental bioassays using healthy engorged female ticks. A morbidity rate of 90% was observed, starting at a concentration of 105 conidia/mL. At a concentration of 107 conidia/mL, we observed a 50% mortality rate and a 21.5% inhibition of oviposition. The highest levels of hatch inhibition (30.8%) and estimated reproduction inhibition (34.64%) were achieved at a concentration of 108 conidia/mL. Furthermore, the tick larval progeny that hatched from the infected tick egg masses showed evident symptoms of Aspergillus infection after incubation.
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Affiliation(s)
- Cesar A. Arreguin-Perez
- Centro Nacional de Investigación Disciplinaria en Salud Animal e Inocuidad, Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias INIFAP, Boulevard Cuauhnahuac 8534, Jiutepec 62574, Morelos, Mexico; (C.A.A.-P.); (E.M.-M.)
- Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Cuernavaca 62209, Morelos, Mexico;
| | - Estefan Miranda-Miranda
- Centro Nacional de Investigación Disciplinaria en Salud Animal e Inocuidad, Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias INIFAP, Boulevard Cuauhnahuac 8534, Jiutepec 62574, Morelos, Mexico; (C.A.A.-P.); (E.M.-M.)
| | - Jorge Luis Folch-Mallol
- Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Cuernavaca 62209, Morelos, Mexico;
| | - Raquel Cossío-Bayúgar
- Centro Nacional de Investigación Disciplinaria en Salud Animal e Inocuidad, Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias INIFAP, Boulevard Cuauhnahuac 8534, Jiutepec 62574, Morelos, Mexico; (C.A.A.-P.); (E.M.-M.)
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Owumi SE, Ajakaiye B, Akinwunmi AO, Nwozo SO, Oyelere AK. The Hydrophobic Extract of Sorghum bicolor (L. Moench) Enriched in Apigenin-Protected Rats against Aflatoxin B1-Associated Hepatorenal Derangement. Molecules 2023; 28:molecules28073013. [PMID: 37049776 PMCID: PMC10095839 DOI: 10.3390/molecules28073013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 03/30/2023] Open
Abstract
Aflatoxin B1 (AFB1) is a recalcitrant metabolite produced by fungi species, and due to its intoxications in animals and humans, it has been classified as a Group 1 carcinogen in humans. Preserving food products with Sorghum bicolor sheath can minimise the contamination of agricultural products and avert ill health occasioned by exposure to AFB1. The current study investigated the ameliorating effect of Sorghum bicolor sheath hydrophobic extract (SBE-HP) enriched in Apigenin (API) on the hepatorenal tissues of rats exposed to AFB1. The SBE-HP was characterised using TLC and LC-MS and was found to be enriched in Apigenin and its methylated analogues. The study used adult male rats divided into four experimental cohorts co-treated with AFB1 (50 µg/kg) and SBE-HP (5 and 10 mg/kg) for 28 days. Biochemical, enzyme-linked immunosorbent assays (ELISA) and histological staining were used to examine biomarkers of hepatorenal function, oxidative status, inflammation and apoptosis, and hepatorenal tissue histo-architectural alterations. Data were analysed using GraphPad Prism 8.3.0, an independent t-test, and a one-way analysis of variance. Co-treatment with SBE-HP ameliorated an upsurge in the biomarkers of hepatorenal functionality in the sera of rats, reduced the alterations in redox balance, resolved inflammation, inhibited apoptosis, and preserved the histological features of the liver and kidney of rats exposed to AFB1. SBE-HP-containing API is an excellent antioxidant regiment. It can amply prevent the induction of oxidative stress, inflammation, and apoptosis in the hepatorenal system of rats. Therefore, supplementing animal feeds and human foods with SBE-HP enriched in Apigenin may reduce the burden of AFB1 intoxication in developing countries with a shortage of effective antifungal agents.
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Affiliation(s)
- Solomon E. Owumi
- Cancer Research and Molecular Biology Laboratories, Department of Biochemistry, Faculty of Basic Medical Sciences, University of Ibadan, Ibadan 200005, Nigeria
- Correspondence: (S.E.O.); (A.K.O.)
| | - Blessing Ajakaiye
- Nutrition and Industrial Biochemistry Laboratories, Department of Biochemistry, Faculty of Basic Medical Sciences, University of Ibadan, Ibadan 200005, Nigeria
| | - Adenike O. Akinwunmi
- Department of Chemistry, Ekiti State University, Ado-Ekiti, Ekiti 360001, Nigeria
| | - Sarah O. Nwozo
- Nutrition and Industrial Biochemistry Laboratories, Department of Biochemistry, Faculty of Basic Medical Sciences, University of Ibadan, Ibadan 200005, Nigeria
| | - Adegboyega K. Oyelere
- School of Chemistry & Biochemistry, Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Correspondence: (S.E.O.); (A.K.O.)
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Multiple Year Influences of the Aflatoxin Biocontrol Product AF-X1 on the A. flavus Communities Associated with Maize Production in Italy. Toxins (Basel) 2023; 15:toxins15030184. [PMID: 36977075 PMCID: PMC10057891 DOI: 10.3390/toxins15030184] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 02/16/2023] [Accepted: 02/24/2023] [Indexed: 03/06/2023] Open
Abstract
AF-X1 is a commercial aflatoxin biocontrol product containing the non-aflatoxigenic (AF-) strain of Aspergillus flavus MUCL54911 (VCG IT006), endemic to Italy, as an active ingredient. The present study aimed to evaluate the long-term persistence of VCG IT006 in the treated fields, and the multi-year influence of the biocontrol application on the A. flavus population. Soil samples were collected in 2020 and 2021 from 28 fields located in four provinces in north Italy. A vegetative compatibility analysis was conducted to monitor the occurrence of VCG IT006 on the total of the 399 isolates of A. flavus that were collected. IT006 was present in all the fields, mainly in the fields treated for 1 yr or 2 consecutive yrs (58% and 63%, respectively). The densities of the toxigenic isolates, detected using the aflR gene, were 45% vs. 22% in the untreated and treated fields, respectively. After displacement via the AF- deployment, a variability from 7% to 32% was noticed in the toxigenic isolates. The current findings support the long-term durability of the biocontrol application benefits without deleterious effects on each fungal population. Nevertheless, based on the current results, as well as on previous studies, the yearly applications of AF-X1 to Italian commercial maize fields should continue.
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Comprehensive Review of Aflatoxin Contamination, Impact on Health and Food Security, and Management Strategies in Pakistan. Toxins (Basel) 2022; 14:toxins14120845. [PMID: 36548742 PMCID: PMC9781569 DOI: 10.3390/toxins14120845] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/22/2022] [Accepted: 11/26/2022] [Indexed: 12/05/2022] Open
Abstract
Aflatoxins (AFs) are the most important toxic, mutagenic, and carcinogenic fungal toxins that routinely contaminate food and feed. While more than 20 AFs have been identified to date, aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2), and M1 (AFM1) are the most common. Over 25 species of Aspergillus have been shown to produce AFs, with Aspergillus flavus, Aspergillus parasiticus, and Aspergillus nomius being the most important and well-known AF-producing fungi. These ubiquitous molds can propagate on agricultural commodities to produce AFs in fields and during harvesting, processing, transportation, and storage. Countries with warmer climates and that produce foods susceptible to AF contamination shoulder a substantial portion of the global AF burden. Pakistan's warm climate promotes the growth of toxigenic fungi, resulting in frequent AF contamination of human foods and animal feeds. The potential for contamination in Pakistan is exacerbated by improper storage conditions and a lack of regulatory limits and enforcement mechanisms. High levels of AFs in common commodities produced in Pakistan are a major food safety problem, posing serious health risks to the population. Furthermore, aflatoxin contamination contributes to economic losses by limiting exports of these commodities. In this review, recent information regarding the fungal producers of AFs, prevalence of AF contamination of foods and feed, current regulations, and AF prevention and removal strategies are summarized, with a major focus on Pakistan.
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Characterization of the Aspergillus flavus Population from Highly Aflatoxin-Contaminated Corn in the United States. Toxins (Basel) 2022; 14:toxins14110755. [PMID: 36356005 PMCID: PMC9698142 DOI: 10.3390/toxins14110755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/23/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022] Open
Abstract
Aflatoxin contamination of corn is a major threat to the safe food and feed. The United States Federal Grain Inspection Service (FGIS) monitors commercial grain shipments for the presence of aflatoxin. A total of 146 Aspergillus flavus were isolated from 29 highly contaminated grain samples to characterize the visual phenotypes, aflatoxin-producing potential, and genotypes to explore the etiological cause of high aflatoxin contamination of US corn. Five of the isolates had reduced sensitivity (43-49% resistant) to the fungicide azoxystrobin, with the remainder all being over 50% resistant to azoxystrobin at the discriminating dose of 2.5 µg/mL. Only six isolates of the highly aflatoxigenic S morphotype were found, and 48 isolates were non-aflatoxigenic. Analysis of the mating type locus revealed 45% MAT 1-1 and 55% MAT 1-2. The A. flavus population originating from the highly aflatoxin contaminated grain samples was compared to a randomly selected subset of isolates originating from commercial corn samples with typical levels of aflatoxin contamination (average < 50 ppb). Use of simple sequence repeat (SSR) genotyping followed by principal component analysis (PCoA) revealed a similar pattern of genotypic distribution in the two populations, but greater diversity in the FGIS-derived population. The noticeable difference between the two populations was that genotypes identical to strain NRRL 21882, the active component of the aflatoxin biocontrol product Afla-Guard™, were ten times more common in the commercial corn population of A. flavus compared to the population from the high-aflatoxin corn samples. The other similarities between the two populations suggest that high aflatoxin concentrations in corn grain are generally the result of infection with common A. flavus genotypes.
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Mahuku G, Mauro A, Pallangyo B, Nsami E, Boni S, Koyano E, Mponda O, Ortega-Beltran A, Atehnkeng J, Aquiline F, Samuel R, Njela J, Cotty P, Bandyopadhyay R. Atoxigenic-based technology for biocontrol of aflatoxin in maize and groundnuts for Tanzania. WORLD MYCOTOXIN J 2022. [DOI: 10.3920/wmj2021.2758] [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
Application of biocontrol products containing atoxigenic isolates of Aspergillus flavus to reduce aflatoxin content in crops is an effective strategy for managing aflatoxin in several regions throughout the world. We report the development and validation of two aflatoxin biocontrol products, Aflasafe TZ01 and Aflasafe TZ02, for use in maize and groundnut in Tanzania, a country frequently affected by aflatoxin contamination. Each product contains four atoxigenic A. flavus genotypes native and widely distributed in Tanzania. Efficacy tests on maize and groundnut were conducted over two years and in four regions of Tanzania where aflatoxin contamination is prevalent. Application of both products significantly (P<0.05) reduced aflatoxin levels in maize and groundnut in both years and in all districts. No differences were observed in total Aspergillus section Flavi population in treated and untreated fields, revealing that application of the biocontrol products do not alter overall Aspergillus populations in the environment. The results indicate that both products are effective tools for aflatoxin mitigation in groundnut and maize. The products were officially registered in 2018. Currently, there are scale-out and-up efforts of aflatoxin biocontrol products in Tanzania through a private sector company that is making the products available to farmers. Protecting maize and groundnut from aflatoxin contamination in Tanzania can result in health, income, and trade benefits.
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Affiliation(s)
- G. Mahuku
- International Institute of Tropical Agriculture (IITA) Eastern Africa Hub, Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P.O. Box 34441, Dar es Salaam, Tanzania
| | - A. Mauro
- International Institute of Tropical Agriculture (IITA) Eastern Africa Hub, Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P.O. Box 34441, Dar es Salaam, Tanzania
| | - B. Pallangyo
- Plant Health Services, Ministry of Agriculture, P.O. Box 2182, Dodoma, Tanzania
| | - E. Nsami
- National Biological Control Center, P.O. Box 30031, Kibaha, Tanzania
| | - S.B. Boni
- International Institute of Tropical Agriculture (IITA) Eastern Africa Hub, Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P.O. Box 34441, Dar es Salaam, Tanzania
- World Vegetable Center, Eastern and Southern Africa, P.O. Box 10, Duluti, Arusha, Tanzania
| | - E. Koyano
- International Institute of Tropical Agriculture (IITA) Eastern Africa Hub, Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P.O. Box 34441, Dar es Salaam, Tanzania
| | - O. Mponda
- Department of Research, Ministry of Agriculture, Livestock and Fisheries, P.O. Box 9192, Dar es Salaam, Tanzania
| | - A. Ortega-Beltran
- IITA Headquarters, PMB 5320, Oyo Road, Ibadan 200001, Oyo State, Nigeria
| | - J. Atehnkeng
- IITA Headquarters, PMB 5320, Oyo Road, Ibadan 200001, Oyo State, Nigeria
| | - F. Aquiline
- International Institute of Tropical Agriculture (IITA) Eastern Africa Hub, Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P.O. Box 34441, Dar es Salaam, Tanzania
| | - R. Samuel
- International Institute of Tropical Agriculture (IITA) Eastern Africa Hub, Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P.O. Box 34441, Dar es Salaam, Tanzania
| | - J. Njela
- International Institute of Tropical Agriculture (IITA) Eastern Africa Hub, Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P.O. Box 34441, Dar es Salaam, Tanzania
| | - P.J. Cotty
- USDA-ARS, 416 West Congress Street, Tucson, AZ 85701, USA
| | - R. Bandyopadhyay
- IITA Headquarters, PMB 5320, Oyo Road, Ibadan 200001, Oyo State, Nigeria
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Mutuli GP, Mbuge DO, Gitau AN. Effect of humidity on aflatoxin contamination for selected African leafy vegetables. JOURNAL OF FOOD SCIENCE AND TECHNOLOGY 2022; 59:2724-2730. [PMID: 35734105 PMCID: PMC9206938 DOI: 10.1007/s13197-021-05293-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 09/22/2021] [Accepted: 10/17/2021] [Indexed: 06/15/2023]
Abstract
In this study, the aflatoxin contamination level of selected freshly harvested and dried African leafy vegetables was investigated after inoculation with Aspergillus flavus spores and incubation at 32%, 74%, 84%, and 96% static relative humidity. The study question was whether Aspergillus sp. growth on selected vegetables: Corchorus olitorius, Crotalaria ochroleuca, Vigna unguiculata, Solanum villosum, and Amaranthus blitum can produce aflatoxins. The experiment was replicated thrice and a control sample was included for each replicate. An Agilent 1260 Infinity HPLC system was used for analysis and we quantified the following aflatoxins; B1, B2, G1, and G2 in the selected vegetables. Our results show that aflatoxin B1, G1, and G2 were all present, with the B1 being prevalent. The contamination level increased with relative humidity increase for both freshly harvested and dried vegetables. However, the dried vegetables had a lower contamination level in comparison with freshly harvested. The findings affirm the importance of post-harvest crop preservation to avoid mycotoxin contamination. The vegetables can suffer aflatoxin contamination when exposed to high moisture and ambient temperature and drying is a suitable method of vegetable preservation.
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Affiliation(s)
- Gibson P. Mutuli
- Department of Environmental and Biosystems Engineering, University of Nairobi, Nairobi, Kenya
| | - Duncan O. Mbuge
- Department of Environmental and Biosystems Engineering, University of Nairobi, Nairobi, Kenya
| | - Ayub N. Gitau
- Department of Environmental and Biosystems Engineering, University of Nairobi, Nairobi, Kenya
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Spadola G, Giannelli G, Magagnoli S, Lanzoni A, Albertini M, Nicoli R, Ferrari R, Burgio G, Restivo FM, Degola F. Validation and Ecological Niche Investigation of a New Fungal Intraspecific Competitor as a Biocontrol Agent for the Sustainable Containment of Aflatoxins on Maize Fields. J Fungi (Basel) 2022; 8:jof8050425. [PMID: 35628681 PMCID: PMC9147465 DOI: 10.3390/jof8050425] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/09/2022] [Accepted: 04/20/2022] [Indexed: 02/01/2023] Open
Abstract
Crop yield and plant products quality are directly or indirectly affected by climate alterations. Adverse climatic conditions often promote the occurrence of different abiotic stresses, which can reduce or enhance the susceptibility to pests or pathogens. Aflatoxin producing fungi, in particular, whose diffusion and deleterious consequences on cereals commodities have been demonstrated to highly depend on the temperature and humidity conditions that threaten increasingly larger areas. Biological methods using intraspecific competitors to prevent fungal development and/or toxin production at the pre-harvest level are particularly promising, even if their efficacy could be affected by the ecological interaction within the resident microbial population. A previously characterized Aspergillus flavus atoxigenic strain was applied in two maize fields to validate its effectiveness as a biocontrol agent against aflatoxin contamination. At one month post-application, at the harvest stage, its persistence within the A. flavus population colonizing the maize kernels in the treated area was assessed, and its efficacy was compared in vitro with a representation of the isolated atoxigenic population. Results proved that our fungal competitor contained the aflatoxin level on maize grains as successfully as a traditional chemical strategy, even if representing less than 30% of the atoxigenic strains re-isolated, and achieved the best performance (in terms of bio-competitive potential) concerning endogenous atoxigenic isolates.
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Affiliation(s)
- Giorgio Spadola
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (G.S.); (G.G.); (F.M.R.)
| | - Gianluigi Giannelli
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (G.S.); (G.G.); (F.M.R.)
| | - Serena Magagnoli
- Department of Agricultural and Food Sciences (DISTAL), University of Bologna, 40127 Bologna, Italy; (S.M.); (A.L.); (G.B.)
| | - Alberto Lanzoni
- Department of Agricultural and Food Sciences (DISTAL), University of Bologna, 40127 Bologna, Italy; (S.M.); (A.L.); (G.B.)
| | - Marco Albertini
- Agrites S.r.l., 40057 Granarolo dell’Emilia, Italy; (M.A.); (R.N.)
| | - Riccardo Nicoli
- Agrites S.r.l., 40057 Granarolo dell’Emilia, Italy; (M.A.); (R.N.)
| | - Roberto Ferrari
- Centro Agricoltura Ambiente “Giorgio Nicoli” S.r.l., 40014 Crevalcore, Italy;
| | - Giovanni Burgio
- Department of Agricultural and Food Sciences (DISTAL), University of Bologna, 40127 Bologna, Italy; (S.M.); (A.L.); (G.B.)
| | - Francesco M. Restivo
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (G.S.); (G.G.); (F.M.R.)
| | - Francesca Degola
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (G.S.); (G.G.); (F.M.R.)
- Correspondence:
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Sserumaga JP, Wagacha JM, Biruma M, Mutegi CK. Contamination of groundnut (Arachis hypogaea L.) with Aspergillus section Flavi communities and aflatoxin at the post-harvest stage. Food Control 2021. [DOI: 10.1016/j.foodcont.2021.108150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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12
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Mohammed A, Faustinelli PC, Chala A, Dejene M, Fininsa C, Ayalew A, Ojiewo CO, Hoisington DA, Sobolev VS, Martínez-Castillo J, Arias RS. Genetic fingerprinting and aflatoxin production of Aspergillus section Flavi associated with groundnut in eastern Ethiopia. BMC Microbiol 2021; 21:239. [PMID: 34454439 PMCID: PMC8403416 DOI: 10.1186/s12866-021-02290-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 07/25/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aspergillus species cause aflatoxin contamination in groundnut kernels, being a health threat in agricultural products and leading to commodity rejection by domestic and international markets. Presence of Aspergillus flavus and A. parasiticus colonizing groundnut in eastern Ethiopia, as well as presence of aflatoxins have been reported, though in this region, no genetic studies have been done of these species in relation to their aflatoxin production. RESULTS In this study, 145 Aspergillus isolates obtained from groundnut kernels in eastern Ethiopia were genetically fingerprinted using 23 Insertion/Deletion (InDel) markers within the aflatoxin-biosynthesis gene cluster (ABC), identifying 133 ABC genotypes. Eighty-four isolates were analyzed by Ultra-Performance Liquid Chromatography (UPLC) for in vitro aflatoxin production. Analysis of genetic distances based on the approximately 85 kb-ABC by Neighbor Joining (NJ), 3D-Principal Coordinate Analysis (3D-PCoA), and Structure software, clustered the isolates into three main groups as a gradient in their aflatoxin production. Group I, contained 98% A. flavus, including L- and non-producers of sclerotia (NPS), producers of B1 and B2 aflatoxins, and most of them collected from the lowland-dry Babile area. Group II was a genetic admixture population of A. flavus (NPS) and A. flavus S morphotype, both low producers of aflatoxins. Group III was primarily represented by A. parasiticus and A. flavus S morphotype isolates both producers of B1, B2 and G1, G2 aflatoxins, and originated from the regions of Darolabu and Gursum. The highest in vitro producer of aflatoxin B1 was A. flavus NPS N1436 (77.98 μg/mL), and the highest producer of aflatoxin G1 was A. parasiticus N1348 (50.33 μg/mL), these isolates were from Gursum and Darolabu, respectively. CONCLUSIONS To the best of our knowledge, this is the first study that combined the use of InDel fingerprinting of the ABC and corresponding aflatoxin production capability to describe the genetic diversity of Aspergillus isolates from groundnut in eastern Ethiopia. Three InDel markers, AFLC04, AFLC08 and AFLC19, accounted for the main assignment of individuals to the three Groups; their loci corresponded to aflC (pksA), hypC, and aflW (moxY) genes, respectively. Despite InDels within the ABC being often associated to loss of aflatoxin production, the vast InDel polymorphism observed in the Aspergillus isolates did not completely impaired their aflatoxin production in vitro.
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Affiliation(s)
- Abdi Mohammed
- School of Plant Science, College of Agriculture and Environmental Sciences, Haramaya University, P.O. Box 138, Dire Dawa, Ethiopia
| | - Paola C Faustinelli
- United States Department of Agriculture-Agricultural Research Service-National Peanut Research Laboratory, Dawson, GA, 39842-0509, USA
| | - Alemayehu Chala
- College of Agriculture, Hawassa University, P.O. Box 5, Hawassa, Ethiopia
| | - Mashilla Dejene
- School of Plant Science, College of Agriculture and Environmental Sciences, Haramaya University, P.O. Box 138, Dire Dawa, Ethiopia
| | - Chemeda Fininsa
- School of Plant Science, College of Agriculture and Environmental Sciences, Haramaya University, P.O. Box 138, Dire Dawa, Ethiopia
| | - Amare Ayalew
- Partnership for Aflatoxin Control in Africa (PACA), African Union Commission, Addis Ababa, Ethiopia
| | - Chris O Ojiewo
- ICRISAT - Nairobi, UN-Avenue, Box 39063-00623, Nairobi, Kenya
| | - David A Hoisington
- College of Agriculture and Environmental Sciences, Peanut and Mycotoxin Innovation Lab, University of Georgia, Athens, GA, 30602-4356, USA
| | - Victor S Sobolev
- United States Department of Agriculture-Agricultural Research Service-National Peanut Research Laboratory, Dawson, GA, 39842-0509, USA
| | - Jaime Martínez-Castillo
- Centro de Investigación Científica de Yucatán A.C., Unidad de Recursos Naturales, Calle 43 No. 130, Colonia Chuburná de Hidalgo CP 97200, Mérida, Mexico
| | - Renee S Arias
- United States Department of Agriculture-Agricultural Research Service-National Peanut Research Laboratory, Dawson, GA, 39842-0509, USA.
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Qureshi MA, Javed S. Aflatoxin B 1 Induced Structural and Conformational Changes in Bovine Serum Albumin: A Multispectroscopic and Circular Dichroism-Based Study. ACS OMEGA 2021; 6:18054-18064. [PMID: 34308039 PMCID: PMC8296610 DOI: 10.1021/acsomega.1c01799] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 06/23/2021] [Indexed: 05/15/2023]
Abstract
Aflatoxin B1 (AFB1) is a mutagen that has been categorized as a group 1 human carcinogen by the International Agency for Research on Cancer. It is produced as a secondary metabolite by soil fungi Aspergillus flavus and Aspergillus parasiticus . Here, in this study, the effect of AFB1 on the structure and conformation of bovine serum albumin (BSA) using multispectroscopic tools like fluorescence spectroscopy, ultraviolet-visible absorption spectroscopy, and circular dichroism spectropolarimetry has been ascertained. Ultraviolet absorption spectroscopy revealed hyperchromicity in the absorption spectra of BSA in the presence of AFB1. The binding constant was calculated in the range of 104 M-1, by fluorescence spectroscopy suggesting moderate binding of the toxin to BSA. The study also confirms the static nature of fluorescence quenching. The stoichiometry of binding sites was found to be unity. The competing capability of warfarin for AFB1 was higher than ibuprofen as calculated from site marker displacement assay. Förster resonance energy transfer confirmed the high efficiency of energy transfer from BSA to AFB1. Circular dichroism spectropolarimetry showed a decrease in the α-helix in BSA in the presence of AFB1. The melting temperature of BSA underwent an increment in the presence of a mycotoxin from 62.5 to 70.3 °C. Molecular docking confirmed the binding of AFB1 to subdomain IIA in BSA.
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14
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Garcia-Lopez MT, Luo Y, Ortega-Beltran A, Jaime R, Moral J, Michailides TJ. Quantification of the Aflatoxin Biocontrol Strain Aspergillus flavus AF36 in Soil and in Nuts and Leaves of Pistachio by Real-Time PCR. PLANT DISEASE 2021; 105:1657-1665. [PMID: 33084543 DOI: 10.1094/pdis-05-20-1097-re] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The species Aspergillus flavus and A. parasiticus are commonly found in the soils of nut-growing areas in California. Several isolates can produce aflatoxins that occasionally contaminate nut kernels, conditioning their sale. Strain AF36 of A. flavus, which does not produce aflatoxins, is registered as a biocontrol agent for use in almond, pistachio, and fig crops in California. After application in orchards, AF36 displaces aflatoxin-producing Aspergillus spp. and thus reduces aflatoxin contamination. Vegetative compatibility assays (VCAs) have traditionally been used to track AF36 in soils and crops where it has been applied. However, VCAs are labor intensive and time consuming. Here, we developed a quantitative real-time PCR (qPCR) protocol to quantify proportions of AF36 accurately and efficiently in different substrates. Specific primers to target AF36 and toxigenic strains of A. flavus and A. parasiticus were designed based on the sequence of aflC, a gene essential for aflatoxin biosynthesis. Standard curves were generated to calculate proportions of AF36 based on threshold cycle values. Verification assays using pure DNA and conidial suspension mixtures demonstrated a significant relationship by regression analysis between known and qPCR-measured AF36 proportions in DNA (R2 = 0.974; P < 0.001) and conidia mixtures (R2 = 0.950; P < 0.001). Tests conducted by qPCR in pistachio leaves, nuts, and soil samples demonstrated the usefulness of the qPCR method to precisely quantify proportions of AF36 in diverse substrates, ensuring important time and cost savings. The outputs of this study will serve to design better aflatoxin management strategies for pistachio and other crops.
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Affiliation(s)
- M Teresa Garcia-Lopez
- Department of Agronomy (Maria de Maeztu Excellence Unit), University of Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
- Department of Plant Pathology, University of California-Davis Kearney Agricultural Research and Extension Center, Parlier, CA 93648, U.S.A
| | - Yong Luo
- Department of Plant Pathology, University of California-Davis Kearney Agricultural Research and Extension Center, Parlier, CA 93648, U.S.A
| | | | - Ramon Jaime
- Department of Plant Pathology, University of California-Davis Kearney Agricultural Research and Extension Center, Parlier, CA 93648, U.S.A
| | - Juan Moral
- Department of Agronomy (Maria de Maeztu Excellence Unit), University of Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
| | - Themis J Michailides
- Department of Plant Pathology, University of California-Davis Kearney Agricultural Research and Extension Center, Parlier, CA 93648, U.S.A
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15
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Khan R, Ghazali FM, Mahyudin NA, Samsudin NIP. Biocontrol of Aflatoxins Using Non-Aflatoxigenic Aspergillus flavus: A Literature Review. J Fungi (Basel) 2021; 7:jof7050381. [PMID: 34066260 PMCID: PMC8151999 DOI: 10.3390/jof7050381] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/07/2021] [Accepted: 05/08/2021] [Indexed: 02/06/2023] Open
Abstract
Aflatoxins (AFs) are mycotoxins, predominantly produced by Aspergillus flavus, A. parasiticus, A. nomius, and A. pseudotamarii. AFs are carcinogenic compounds causing liver cancer in humans and animals. Physical and biological factors significantly affect AF production during the pre-and post-harvest time. Several methodologies have been developed to control AF contamination, yet; they are usually expensive and unfriendly to the environment. Consequently, interest in using biocontrol agents has increased, as they are convenient, advanced, and friendly to the environment. Using non-aflatoxigenic strains of A. flavus (AF−) as biocontrol agents is the most promising method to control AFs’ contamination in cereal crops. AF− strains cannot produce AFs due to the absence of polyketide synthase genes or genetic mutation. AF− strains competitively exclude the AF+ strains in the field, giving an extra advantage to the stored grains. Several microbiological, molecular, and field-based approaches have been used to select a suitable biocontrol agent. The effectiveness of biocontrol agents in controlling AF contamination could reach up to 99.3%. Optimal inoculum rate and a perfect time of application are critical factors influencing the efficacy of biocontrol agents.
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Affiliation(s)
- Rahim Khan
- Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang 43400, Malaysia; (R.K.); (N.I.P.S.)
| | - Farinazleen Mohamad Ghazali
- Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang 43400, Malaysia; (R.K.); (N.I.P.S.)
- Correspondence: ; Tel.: +60-12219-8912
| | - Nor Ainy Mahyudin
- Department of Food Service and Management, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang 43400, Malaysia;
- Laboratory of Halal Science Research, Halal Products Research Institute, Universiti Putra Malaysia, Serdang 43400, Malaysia
| | - Nik Iskandar Putra Samsudin
- Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang 43400, Malaysia; (R.K.); (N.I.P.S.)
- Laboratory of Food Safety and Food Integrity, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang 43400, Malaysia
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16
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Agbetiameh D, Ortega-Beltran A, Awuah RT, Atehnkeng J, Elzein A, Cotty PJ, Bandyopadhyay R. Field efficacy of two atoxigenic biocontrol products for mitigation of aflatoxin contamination in maize and groundnut in Ghana. BIOLOGICAL CONTROL : THEORY AND APPLICATIONS IN PEST MANAGEMENT 2020; 150:104351. [PMID: 33144821 PMCID: PMC7457722 DOI: 10.1016/j.biocontrol.2020.104351] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/13/2020] [Accepted: 06/15/2020] [Indexed: 06/11/2023]
Abstract
Biological control is one of the recommended methods for aflatoxin mitigation. Biocontrol products must be developed, and their efficacy demonstrated before widespread use. Efficacy of two aflatoxin biocontrol products, Aflasafe GH01 and Aflasafe GH02, were evaluated in 800 maize and groundnut farmers' fields during 2015 and 2016 in the Ashanti, Brong Ahafo, Northern, Upper East, and Upper West regions of Ghana. Both products were developed after an extensive examination of fungi associated with maize and groundnut in Ghana. Each product contains as active ingredient fungi four Aspergillus flavus isolates belonging to atoxigenic African Aspergillus Vegetative Compatibility Groups (AAVs) widely distributed across Ghana. An untreated field was maintained for each treated field to determine product efficacy. Proportions of atoxigenic AAVs composing each product were assessed in soils before product application, and soils and grains at harvest. Significant (P < 0.05) displacement of toxigenic fungi occurred in both crops during both years, in all five regions. Biocontrol-treated crops consistently had significantly (P < 0.05) less aflatoxins (range = 76% to 100% less; average = 99% less) than untreated crops. Results indicate that both biocontrol products are highly efficient, cost-effective, environmentally safe tools for aflatoxin mitigation. Most crops from treated fields could have been sold in both local and international food and feed premium markets. Adoption and use of biocontrol products have the potential to improve the health of Ghanaians, and both income and trade opportunities of farmers, aggregators, distributors, and traders.
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Affiliation(s)
- Daniel Agbetiameh
- International Institute of Tropical Agriculture (IITA), Ibadan 200001, Nigeria
- Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | | | - Richard T. Awuah
- Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Joseph Atehnkeng
- International Institute of Tropical Agriculture (IITA), Ibadan 200001, Nigeria
| | - Abuelgasim Elzein
- International Institute of Tropical Agriculture (IITA), Ibadan 200001, Nigeria
| | - Peter J. Cotty
- United States Department of Agriculture – Agricultural Research Service, Tucson, AZ 85721, USA
- School of Food Science and Engineering, Ocean University of China, Qingdao, China
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17
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Otto M, Pretorius B, Kritzinger Q, Schönfeldt H. Contamination of freshly harvested Bambara groundnut (
Vigna subterranea
) seed from Mpumalanga, South Africa, with mycotoxigenic fungi. J Food Saf 2020. [DOI: 10.1111/jfs.12846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Margot Otto
- Department of Animal and Wildlife Science, Institute of Food Nutrition and Well‐Being University of Pretoria Pretoria South Africa
| | - Beulah Pretorius
- Department of Animal and Wildlife Science, Institute of Food Nutrition and Well‐Being University of Pretoria Pretoria South Africa
| | - Quenton Kritzinger
- Department of Plant and Soil Sciences University of Pretoria Pretoria South Africa
| | - Hettie Schönfeldt
- Department of Animal and Wildlife Science, Institute of Food Nutrition and Well‐Being University of Pretoria Pretoria South Africa
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18
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Savić Z, Dudaš T, Loc M, Grahovac M, Budakov D, Jajić I, Krstović S, Barošević T, Krska R, Sulyok M, Stojšin V, Petreš M, Stankov A, Vukotić J, Bagi F. Biological Control of Aflatoxin in Maize Grown in Serbia. Toxins (Basel) 2020; 12:toxins12030162. [PMID: 32150883 PMCID: PMC7150810 DOI: 10.3390/toxins12030162] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/14/2020] [Accepted: 03/03/2020] [Indexed: 11/18/2022] Open
Abstract
Aspergillus flavus is the main producer of aflatoxin B1, one of the most toxic contaminants of food and feed. With global warming, climate conditions have become favourable for aflatoxin contamination of agricultural products in several European countries, including Serbia. The infection of maize with A. flavus, and aflatoxin synthesis can be controlled and reduced by application of a biocontrol product based on non-toxigenic strains of A. flavus. Biological control relies on competition between atoxigenic and toxigenic strains. This is the most commonly used biological control mechanism of aflatoxin contamination in maize in countries where aflatoxins pose a significant threat. Mytoolbox Af01, a native atoxigenic A. flavus strain, was obtained from maize grown in Serbia and used to produce a biocontrol product that was applied in irrigated and non-irrigated Serbian fields during 2016 and 2017. The application of this biocontrol product reduced aflatoxin levels in maize kernels (51–83%). The biocontrol treatment had a highly significant effect of reducing total aflatoxin contamination by 73%. This study showed that aflatoxin contamination control in Serbian maize can be achieved through biological control methods using atoxigenic A. flavus strains.
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Affiliation(s)
- Zagorka Savić
- Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad, Serbia; (Z.S.); (M.L.); (M.G.); (D.B.); (I.J.); (S.K.); (T.B.); (V.S.); (M.P.); (A.S.); (J.V.); (F.B.)
| | - Tatjana Dudaš
- Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad, Serbia; (Z.S.); (M.L.); (M.G.); (D.B.); (I.J.); (S.K.); (T.B.); (V.S.); (M.P.); (A.S.); (J.V.); (F.B.)
- Correspondence:
| | - Marta Loc
- Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad, Serbia; (Z.S.); (M.L.); (M.G.); (D.B.); (I.J.); (S.K.); (T.B.); (V.S.); (M.P.); (A.S.); (J.V.); (F.B.)
| | - Mila Grahovac
- Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad, Serbia; (Z.S.); (M.L.); (M.G.); (D.B.); (I.J.); (S.K.); (T.B.); (V.S.); (M.P.); (A.S.); (J.V.); (F.B.)
| | - Dragana Budakov
- Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad, Serbia; (Z.S.); (M.L.); (M.G.); (D.B.); (I.J.); (S.K.); (T.B.); (V.S.); (M.P.); (A.S.); (J.V.); (F.B.)
| | - Igor Jajić
- Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad, Serbia; (Z.S.); (M.L.); (M.G.); (D.B.); (I.J.); (S.K.); (T.B.); (V.S.); (M.P.); (A.S.); (J.V.); (F.B.)
| | - Saša Krstović
- Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad, Serbia; (Z.S.); (M.L.); (M.G.); (D.B.); (I.J.); (S.K.); (T.B.); (V.S.); (M.P.); (A.S.); (J.V.); (F.B.)
| | - Tijana Barošević
- Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad, Serbia; (Z.S.); (M.L.); (M.G.); (D.B.); (I.J.); (S.K.); (T.B.); (V.S.); (M.P.); (A.S.); (J.V.); (F.B.)
| | - Rudolf Krska
- Institute of Bioanalytics and Agro-Metabolomics, Department IFA-Tulin, University of Natural Resources and Life Sciences Vienna (BOKU), A-3430 Tulln, Austria; (R.K.); (M.S.)
- Institute for Global Food Security, School of Biological Sciences, Queens University Belfast, University Road, Belfast BT7 1NN, UK
| | - Michael Sulyok
- Institute of Bioanalytics and Agro-Metabolomics, Department IFA-Tulin, University of Natural Resources and Life Sciences Vienna (BOKU), A-3430 Tulln, Austria; (R.K.); (M.S.)
| | - Vera Stojšin
- Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad, Serbia; (Z.S.); (M.L.); (M.G.); (D.B.); (I.J.); (S.K.); (T.B.); (V.S.); (M.P.); (A.S.); (J.V.); (F.B.)
| | - Mladen Petreš
- Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad, Serbia; (Z.S.); (M.L.); (M.G.); (D.B.); (I.J.); (S.K.); (T.B.); (V.S.); (M.P.); (A.S.); (J.V.); (F.B.)
| | - Aleksandra Stankov
- Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad, Serbia; (Z.S.); (M.L.); (M.G.); (D.B.); (I.J.); (S.K.); (T.B.); (V.S.); (M.P.); (A.S.); (J.V.); (F.B.)
| | - Jelena Vukotić
- Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad, Serbia; (Z.S.); (M.L.); (M.G.); (D.B.); (I.J.); (S.K.); (T.B.); (V.S.); (M.P.); (A.S.); (J.V.); (F.B.)
| | - Ferenc Bagi
- Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad, Serbia; (Z.S.); (M.L.); (M.G.); (D.B.); (I.J.); (S.K.); (T.B.); (V.S.); (M.P.); (A.S.); (J.V.); (F.B.)
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19
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Senghor LA, Ortega-Beltran A, Atehnkeng J, Callicott KA, Cotty PJ, Bandyopadhyay R. The Atoxigenic Biocontrol Product Aflasafe SN01 Is a Valuable Tool to Mitigate Aflatoxin Contamination of Both Maize and Groundnut Cultivated in Senegal. PLANT DISEASE 2020; 104:510-520. [PMID: 31790640 DOI: 10.1094/pdis-03-19-0575-re] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Aflatoxin contamination of groundnut and maize infected by Aspergillus section Flavi fungi is common throughout Senegal. The use of biocontrol products containing atoxigenic Aspergillus flavus strains to reduce crop aflatoxin content has been successful in several regions, but no such products are available in Senegal. The biocontrol product Aflasafe SN01 was developed for use in Senegal. The four active ingredients of Aflasafe SN01 are atoxigenic A. flavus genotypes native to Senegal and distinct from active ingredients used in other biocontrol products. Efficacy tests on groundnut and maize in farmers' fields were carried out in Senegal during the course of 5 years. Active ingredients were monitored with vegetative compatibility analyses. Significant (P < 0.05) displacement of aflatoxin producers occurred in all years, districts, and crops. In addition, crops from Aflasafe SN01-treated fields contained significantly (P < 0.05) fewer aflatoxins both at harvest and after storage. Most crops from treated fields contained aflatoxin concentrations permissible in both local and international markets. Results suggest that Aflasafe SN01 is an effective tool for aflatoxin mitigation in groundnut and maize. Large-scale use of Aflasafe SN01 should provide health, trade, and economic benefits for Senegal.[Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- L A Senghor
- La Direction de Protection Végétaux, BP20054 Dakar, Senegal
| | - A Ortega-Beltran
- International Institute of Tropical Agriculture, Ibadan, Nigeria
| | - J Atehnkeng
- Chitedze Research Station, International Institute of Tropical Agriculture, Lilongwe, Malawi
| | - K A Callicott
- U.S. Department of Agriculture-Agricultural Research Service, School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, U.S.A
| | - P J Cotty
- U.S. Department of Agriculture-Agricultural Research Service, School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, U.S.A
| | - R Bandyopadhyay
- International Institute of Tropical Agriculture, Ibadan, Nigeria
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20
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Shenge KC, Adhikari BN, Akande A, Callicott KA, Atehnkeng J, Ortega-Beltran A, Kumar PL, Bandyopadhyay R, Cotty PJ. Monitoring Aspergillus flavus Genotypes in a Multi-Genotype Aflatoxin Biocontrol Product With Quantitative Pyrosequencing. Front Microbiol 2019; 10:2529. [PMID: 31803149 PMCID: PMC6872644 DOI: 10.3389/fmicb.2019.02529] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 10/21/2019] [Indexed: 11/13/2022] Open
Abstract
Aflatoxins pose significant food security and public health risks, decrease productivity and profitability of animal industries, and hamper trade. To minimize aflatoxin contamination in several crops, a biocontrol technology based on atoxigenic strains of Aspergillus flavus is commercially used in the United States and some African countries. Significant efforts are underway to popularize the use of biocontrol in Africa by various means including incentives. The purpose of this study was to develop quantitative pyrosequencing assays for rapid, simultaneous quantification of proportions of four A. flavus biocontrol genotypes within complex populations of A. flavus associated with maize crops in Nigeria to facilitate payment of farmer incentives for Aflasafe (a biocontrol product) use. Protocols were developed to confirm use of Aflasafe by small scale farmers in Nigeria. Nested PCR amplifications followed by sequence by synthesis pyrosequencing assays were required to quantify frequencies of the active ingredients and, in so doing, confirm successful use of biocontrol by participating farmers. The entire verification process could be completed in 3-4 days proving a savings over other monitoring methods in both time and costs and providing data in a time frame that could work with the commercial agriculture scheme. Quantitative pyrosequencing assays represent a reliable tool for rapid detection, quantification, and monitoring of multiple A. flavus genotypes within complex fungal communities, satisfying the requirements of the regulatory community and crop end-users that wish to determine which purchased crops were treated with the biocontrol product. Techniques developed in the current study can be modified for monitoring other crop-associated fungi.
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Affiliation(s)
- Kenneth C. Shenge
- United States Department of Agriculture, Agricultural Research Service, Tucson, AZ, United States
| | - Bishwo N. Adhikari
- United States Department of Agriculture, Agricultural Research Service, Tucson, AZ, United States
| | | | - Kenneth A. Callicott
- United States Department of Agriculture, Agricultural Research Service, Tucson, AZ, United States
| | - Joseph Atehnkeng
- International Institute of Tropical Agriculture, Ibadan, Nigeria
| | | | - P. Lava Kumar
- International Institute of Tropical Agriculture, Ibadan, Nigeria
| | | | - Peter J. Cotty
- United States Department of Agriculture, Agricultural Research Service, Tucson, AZ, United States
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21
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Bandyopadhyay R, Atehnkeng J, Ortega-Beltran A, Akande A, Falade TDO, Cotty PJ. "Ground-Truthing" Efficacy of Biological Control for Aflatoxin Mitigation in Farmers' Fields in Nigeria: From Field Trials to Commercial Usage, a 10-Year Study. Front Microbiol 2019; 10:2528. [PMID: 31824438 PMCID: PMC6882503 DOI: 10.3389/fmicb.2019.02528] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 10/21/2019] [Indexed: 01/09/2023] Open
Abstract
In sub-Saharan Africa (SSA), diverse fungi belonging to Aspergillus section Flavi frequently contaminate staple crops with aflatoxins. Aflatoxins negatively impact health, income, trade, food security, and development sectors. Aspergillus flavus is the most common causal agent of contamination. However, certain A. flavus genotypes do not produce aflatoxins (i.e., are atoxigenic). An aflatoxin biocontrol technology employing atoxigenic genotypes to limit crop contamination was developed in the United States. The technology was adapted and improved for use in maize and groundnut in SSA under the trademark Aflasafe. Nigeria was the first African nation for which an aflatoxin biocontrol product was developed. The current study includes tests to assess biocontrol performance across Nigeria over the past decade. The presented data on efficacy spans years in which a relatively small number of maize and groundnut fields (8-51 per year) were treated through use on circa 36,000 ha in commercially-produced maize in 2018. During the testing phase (2009-2012), fields treated during one year were not treated in the other years while during commercial usage (2013-2019), many fields were treated in multiple years. This is the first report of a large-scale, long-term efficacy study of any biocontrol product developed to date for a field crop. Most (>95%) of 213,406 tons of maize grains harvested from treated fields contained <20 ppb total aflatoxins, and a significant proportion (>90%) contained <4 ppb total aflatoxins. Grains from treated plots had preponderantly >80% less aflatoxin content than untreated crops. The frequency of the biocontrol active ingredient atoxigenic genotypes in grains from treated fields was significantly higher than in grains from control fields. A higher proportion of grains from treated fields met various aflatoxin standards compared to grains from untreated fields. Results indicate that efficacy of the biocontrol product in limiting aflatoxin contamination is stable regardless of environment and cropping system. In summary, the biocontrol technology allows farmers across Nigeria to produce safer crops for consumption and increases potential for access to premium markets that require aflatoxin-compliant crops.
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Affiliation(s)
| | - Joseph Atehnkeng
- International Institute of Tropical Agriculture, Ibadan, Nigeria
| | | | | | | | - Peter J. Cotty
- Agricultural Research Service, United States Department of Agriculture, Tucson, AZ, United States
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Agbetiameh D, Ortega-Beltran A, Awuah RT, Atehnkeng J, Islam MS, Callicott KA, Cotty PJ, Bandyopadhyay R. Potential of Atoxigenic Aspergillus flavus Vegetative Compatibility Groups Associated With Maize and Groundnut in Ghana as Biocontrol Agents for Aflatoxin Management. Front Microbiol 2019; 10:2069. [PMID: 31555251 PMCID: PMC6743268 DOI: 10.3389/fmicb.2019.02069] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 08/22/2019] [Indexed: 11/24/2022] Open
Abstract
Increasing knowledge of the deleterious health and economic impacts of aflatoxin in crop commodities has stimulated global interest in aflatoxin mitigation. Current evidence of the incidence of Aspergillus flavus isolates belonging to vegetative compatibility groups (VCGs) lacking the ability to produce aflatoxins (i.e., atoxigenic) in Ghana may lead to the development of an aflatoxin biocontrol strategy to mitigate crop aflatoxin content. In this study, 12 genetically diverse atoxigenic African A. flavus VCGs (AAVs) were identified from fungal communities associated with maize and groundnut grown in Ghana. Representative isolates of the 12 AAVs were assessed for their ability to inhibit aflatoxin contamination by an aflatoxin-producing isolate in laboratory assays. Then, the 12 isolates were evaluated for their potential as biocontrol agents for aflatoxin mitigation when included in three experimental products (each containing four atoxigenic isolates). The three experimental products were evaluated in 50 maize and 50 groundnut farmers' fields across three agroecological zones (AEZs) in Ghana during the 2014 cropping season. In laboratory assays, the atoxigenic isolates reduced aflatoxin biosynthesis by 87-98% compared to grains inoculated with the aflatoxin-producing isolate alone. In field trials, the applied isolates moved to the crops and had higher (P < 0.05) frequencies than other A. flavus genotypes. In addition, although at lower frequencies, most atoxigenic genotypes were repeatedly found in untreated crops. Aflatoxin levels in treated crops were lower by 70-100% in groundnut and by 50-100% in maize (P < 0.05) than in untreated crops. Results from the current study indicate that combined use of appropriate, well-adapted isolates of atoxigenic AAVs as active ingredients of biocontrol products effectively displace aflatoxin producers and in so doing limit aflatoxin contamination. A member each of eight atoxigenic AAVs with superior competitive potential and wide adaptation across AEZs were selected for further field efficacy trials in Ghana. A major criterion for selection was the atoxigenic isolate's ability to colonize soils and grains after release in crop field soils. Use of isolates belonging to atoxigenic AAVs in biocontrol management strategies has the potential to improve food safety, productivity, and income opportunities for smallholder farmers in Ghana.
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Affiliation(s)
- Daniel Agbetiameh
- International Institute of Tropical Agriculture, Ibadan, Nigeria
- Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | | | - Richard T. Awuah
- Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Joseph Atehnkeng
- International Institute of Tropical Agriculture, Ibadan, Nigeria
| | - Md-Sajedul Islam
- Agricultural Research Service, United States Department of Agriculture, Tucson, AZ, United States
| | - Kenneth A. Callicott
- Agricultural Research Service, United States Department of Agriculture, Tucson, AZ, United States
| | - Peter J. Cotty
- Agricultural Research Service, United States Department of Agriculture, Tucson, AZ, United States
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A Polyphasic Approach Aids Early Detection of Potentially Toxigenic Aspergilli in Soil. Microorganisms 2019; 7:microorganisms7090300. [PMID: 31470555 PMCID: PMC6781248 DOI: 10.3390/microorganisms7090300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 08/24/2019] [Accepted: 08/26/2019] [Indexed: 11/16/2022] Open
Abstract
Key chili and maize growing areas of Pakistan were selected for a focused baseline study of the levels of Aspergillus spp. Investigations were undertaken using a combination of molecular and culture-based techniques. Samples investigated included soil samples, one-year-old corn cobs, and fresh chili from selected locations. Aspergillus strains obtained from corn cobs were screened using coconut milk agar, resulting in one strain that was positive for aflatoxin production. Whole genome sequencing (WGS) with low coverage techniques were employed to screen the isolates for differences in the ribosomal RNA gene cluster and mitochondrial genome, with the aflatoxigenic strain proving to have a distinctive profile. Finally, strains were subjected to matrix-assisted laser-desorption and ionization time-of-flight mass spectrometry (MALDI-ToF-MS) in order to obtain a proteomic ‘fingerprint’ which was used to distinguish the aflatoxigenic strain from the other isolates. The next generation sequencing (NGS) study was broadened to incorporate metabarcoding with ITS rRNA for determining the microbial biodiversity of the soil samples and presumptive screening for the presence of aflatoxigenic strains. Using information gleaned from the WGS results, a putative aflatoxigenic operational taxonomic unit (OTU) was observed in four of the 15 soil samples screened by metabarcoding. This method may have beneficial applications in early detection and surveillance programs in agricultural soils and commodities.
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Mycotoxin Contamination of Edible Non-Timber Forest Products in Cameroon. Toxins (Basel) 2019; 11:toxins11070430. [PMID: 31336631 PMCID: PMC6669663 DOI: 10.3390/toxins11070430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 07/07/2019] [Accepted: 07/12/2019] [Indexed: 11/17/2022] Open
Abstract
The prevalence and concentrations of three major mycotoxins, total aflatoxin (AFs), fumonisin (F), and zearalenone (ZEN), were determined on seven edible non-timber forest products (ENTFP) in Cameroon. A total of 210 samples consiting of 30 samples from each ENTFP commodity was collected from farmers and local markets in three agroecological zones of Cameroon and analyzed for moisture content and mycotoxins. Mycotoxins were analyzed using commercial enzyme-linked immunosorbent assay (ELISA) kits and results were validated using the VICAM fluorometric method. The European Union regulation of mycotoxins for human consumption (N°1881/2006) was adopted as reference. The moisture content of samples varied from 5.0% to 22.6%. Aflatoxin contamination was detected in 84.3% samples and only 5.7% exceeded the legal limit (10 ppb). Similarly, 53% of samples were contaminated with fumonisin and 5% of samples exceeded the legal limit (1000 ppb). Zearalenone contamination was detected in 92% of samples and 21% of samples exceeded the legal limit (100 ppb). This is the first report on mycotoxin contamination of ENTFP in the Congo Basin forest. The findings of this study will form a basis for educating farmers and other stakeholders of ENTFP values chain on mycotoxins and mycotoxin mitigation measures to produce safe ENTFP for local and international markets.
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Ortega-Beltran A, Moral J, Picot A, Puckett RD, Cotty PJ, Michailides TJ. Atoxigenic Aspergillus flavus Isolates Endemic to Almond, Fig, and Pistachio Orchards in California with Potential to Reduce Aflatoxin Contamination in these Crops. PLANT DISEASE 2019; 103:905-912. [PMID: 30807246 DOI: 10.1094/pdis-08-18-1333-re] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In California, aflatoxin contamination of almond, fig, and pistachio has become a serious problem in recent years due to long periods of drought and probably other climatic changes. The atoxigenic biocontrol product Aspergillus flavus AF36 has been registered for use to limit aflatoxin contamination of pistachio since 2012 and for use in almond and fig since 2017. New biocontrol technologies employ multiple atoxigenic genotypes because those provide greater benefits than using a single genotype. Almond, fig, and pistachio industries would benefit from a multi-strain biocontrol technology for use in these three crops. Several A. flavus vegetative compatibility groups (VCGs) associated with almond, fig, and pistachio composed exclusively of atoxigenic isolates, including the VCG to which AF36 belongs to, YV36, were previously characterized in California. Here, we report additional VCGs associated with either two or all three crops. Representative isolates of 12 atoxigenic VCGs significantly (P < 0.001) reduced (>80%) aflatoxin accumulation in almond and pistachio when challenged with highly toxigenic isolates of A. flavus and A. parasiticus under laboratory conditions. Isolates of the evaluated VCGs, including AF36, constitute valuable endemic, well-adapted, and efficient germplasm to design a multi-crop, multi-strain biocontrol strategy for use in tree crops in California. Availability of such a strategy would favor long-term atoxigenic A. flavus communities across the affected areas of California, and this would result in securing domestic and export markets for the nut crop and fig farmer industries and, most importantly, health benefits to consumers.
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Affiliation(s)
- Alejandro Ortega-Beltran
- 1 Department of Plant Pathology, University of California, Davis, and Kearney Agricultural Research and Extension Center, Parlier, CA 93648; and
| | - Juan Moral
- 1 Department of Plant Pathology, University of California, Davis, and Kearney Agricultural Research and Extension Center, Parlier, CA 93648; and
| | - Adeline Picot
- 1 Department of Plant Pathology, University of California, Davis, and Kearney Agricultural Research and Extension Center, Parlier, CA 93648; and
| | - Ryan D Puckett
- 1 Department of Plant Pathology, University of California, Davis, and Kearney Agricultural Research and Extension Center, Parlier, CA 93648; and
| | - Peter J Cotty
- 2 United States Department of Agriculture-Agricultural Research Service, School of Plant Sciences, The University of Arizona, Tucson, AZ 85721
| | - Themis J Michailides
- 1 Department of Plant Pathology, University of California, Davis, and Kearney Agricultural Research and Extension Center, Parlier, CA 93648; and
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27
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Review: Biotechnology of mycotoxins detoxification using microorganisms and enzymes. Toxicon 2019; 160:12-22. [DOI: 10.1016/j.toxicon.2019.02.001] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/23/2018] [Accepted: 02/03/2019] [Indexed: 01/22/2023]
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Pennerman KK, Gonzalez J, Chenoweth LR, Bennett JW, Yin G, Hua SST. Biocontrol strain Aspergillus flavus WRRL 1519 has differences in chromosomal organization and an increased number of transposon-like elements compared to other strains. Mol Genet Genomics 2018; 293:1507-1522. [DOI: 10.1007/s00438-018-1474-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 07/10/2018] [Indexed: 12/14/2022]
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Ortega-Beltran A, Cotty PJ. Frequent Shifts in Aspergillus flavus Populations Associated with Maize Production in Sonora, Mexico. PHYTOPATHOLOGY 2018; 108:412-420. [PMID: 29027887 DOI: 10.1094/phyto-08-17-0281-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Aspergillus flavus frequently contaminates maize, a critical staple for billions of people, with aflatoxins. Diversity among A. flavus L morphotype populations associated with maize in Sonora, Mexico was assessed and, in total, 869 isolates from 83 fields were placed into 136 vegetative compatibility groups (VCGs) using nitrate-nonutilizing mutants. VCG diversity indices did not differ in four agroecosystems (AES) but diversity significantly differed among years. Frequencies of certain VCGs changed manyfold over single years in both multiple fields and multiple AES. Certain VCGs were highly frequent (>1%) in 2006 but frequencies declined repeatedly in each of the two subsequent years. Other VCGs that had low frequencies in 2006 increased in 2007 and subsequently declined. None of the VCGs were consistently associated with any AES. Fourteen VCGs were considered dominant in at least a single year. However, frequencies often varied significantly among years. Only 9% of VCGs were detected all 3 years whereas 66% were detected in only 1 year. Results suggest that the most realistic measurements of both genetic diversity and the frequency of A. flavus VCGs are obtained by sampling multiple locations in multiple years. Single-season sampling in many locations should not be substituted for sampling over multiple years.
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Affiliation(s)
- A Ortega-Beltran
- First and second authors: School of Plant Sciences, and second author: United States Department of Agriculture-Agricultural Research Service, School of Plant Sciences, The University of Arizona, Tucson
| | - P J Cotty
- First and second authors: School of Plant Sciences, and second author: United States Department of Agriculture-Agricultural Research Service, School of Plant Sciences, The University of Arizona, Tucson
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30
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Kos J, Janić-Hajnal E, Šarić L, Plavšić D, Bursić V, Vuković G, Lazarević J. Influence of storage period on occurrence and distribution of aflatoxins and fungi in maize kernels. FOOD AND FEED RESEARCH 2018. [DOI: 10.5937/ffr1802097k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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31
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Baranyi N, Kocsubé S, Jakšić Despot D, Šegvić Klarić M, Szekeres A, Bencsik O, Kecskeméti A, Manikandan P, Tóth B, Kredics L, Khaled JM, Alharbi NS, Vágvölgyi C, Varga J. Combined genotyping strategy reveals structural differences between Aspergillus flavus lineages from different habitats impacting human health. J Basic Microbiol 2017; 57:899-909. [PMID: 28902962 DOI: 10.1002/jobm.201700243] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/24/2017] [Accepted: 08/17/2017] [Indexed: 11/07/2022]
Abstract
Aspergillus flavus is a filamentous fungus which is widespread on agricultural products and also able to cause various human diseases. This species is frequently isolated from indoor air as well, furthermore, it is known as a common causal agent of keratomycosis, particularly in subtropical and tropical areas. It is also able to produce aflatoxins, one of the most carcinogenic mycotoxins which are harmful to animals and humans. In this study, 59 A. flavus isolates from four different habitats and 1 A. minisclerotigenes isolate were investigated. The isolates were identified and confirmed at the species level by the sequence analysis of a part of their calmodulin gene. Applying a combined analysis of UP-PCR, microsatellite, and calmodulin sequence data, the four group of isolates formed separate clusters on the phylogenetic tree. Examining the distribution of mating type genes MAT1-1 and MAT1-2, a ratio of approximately 3:1 was determined, and no correlation was found between the carried mating type gene and the aflatoxin production capability. HPLC analysis revealed that none of the examined isolates collected from indoor air or maize in Central Europe were able to produce aflatoxins, while about half of the isolates from India produced these mycotoxins under the test conditions.
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Affiliation(s)
- Nikolett Baranyi
- Faculty of Science and Informatics, Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Sándor Kocsubé
- Faculty of Science and Informatics, Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Daniela Jakšić Despot
- Faculty of Pharmacy and Biochemistry, Department of Microbiology, University of Zagreb, Zagreb, Croatia
| | - Maja Šegvić Klarić
- Faculty of Pharmacy and Biochemistry, Department of Microbiology, University of Zagreb, Zagreb, Croatia
| | - András Szekeres
- Faculty of Science and Informatics, Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Ottó Bencsik
- Faculty of Science and Informatics, Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Anita Kecskeméti
- Faculty of Science and Informatics, Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Palanisamy Manikandan
- Greenlink Analytical and Research Laboratory India Private Ltd, Coimbatore, Tamilnadu, India
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Majmaah University, Al-Majmaah, Saudi Arabia
| | - Beáta Tóth
- National Agricultural Research and Innovation Center, NÖKO, Szeged, Hungary
| | - László Kredics
- Faculty of Science and Informatics, Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Jamal M Khaled
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | - Naiyf S Alharbi
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | - Csaba Vágvölgyi
- Faculty of Science and Informatics, Department of Microbiology, University of Szeged, Szeged, Hungary
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | - János Varga
- Faculty of Science and Informatics, Department of Microbiology, University of Szeged, Szeged, Hungary
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Bandyopadhyay R, Ortega-Beltran A, Akande A, Mutegi C, Atehnkeng J, Kaptoge L, Senghor A, Adhikari B, Cotty P. Biological control of aflatoxins in Africa: current status and potential challenges in the face of climate change. WORLD MYCOTOXIN J 2016. [DOI: 10.3920/wmj2016.2130] [Citation(s) in RCA: 180] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Aflatoxin contamination of crops is frequent in warm regions across the globe, including large areas in sub-Saharan Africa. Crop contamination with these dangerous toxins transcends health, food security, and trade sectors. It cuts across the value chain, affecting farmers, traders, markets, and finally consumers. Diverse fungi within Aspergillus section Flavi contaminate crops with aflatoxins. Within these Aspergillus communities, several genotypes are not capable of producing aflatoxins (atoxigenic). Carefully selected atoxigenic genotypes in biological control (biocontrol) formulations efficiently reduce aflatoxin contamination of crops when applied prior to flowering in the field. This safe and environmentally friendly, effective technology was pioneered in the US, where well over a million acres of susceptible crops are treated annually. The technology has been improved for use in sub-Saharan Africa, where efforts are under way to develop biocontrol products, under the trade name Aflasafe, for 11 African nations. The number of participating nations is expected to increase. In parallel, state of the art technology has been developed for large-scale inexpensive manufacture of Aflasafe products under the conditions present in many African nations. Results to date indicate that all Aflasafe products, registered and under experimental use, reduce aflatoxin concentrations in treated crops by >80% in comparison to untreated crops in both field and storage conditions. Benefits of aflatoxin biocontrol technologies are discussed along with potential challenges, including climate change, likely to be faced during the scaling-up of Aflasafe products. Lastly, we respond to several apprehensions expressed in the literature about the use of atoxigenic genotypes in biocontrol formulations. These responses relate to the following apprehensions: sorghum as carrier, distribution costs, aflatoxin-conscious markets, efficacy during drought, post-harvest benefits, risk of allergies and/or aspergillosis, influence of Aflasafe on other mycotoxins and on soil microenvironment, dynamics of Aspergillus genotypes, and recombination between atoxigenic and toxigenic genotypes in natural conditions.
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Affiliation(s)
- R. Bandyopadhyay
- International Institute of Tropical Agriculture (IITA), PMB 5320, Oyo Road, 200001 Ibadan, Nigeria
| | - A. Ortega-Beltran
- International Institute of Tropical Agriculture (IITA), PMB 5320, Oyo Road, 200001 Ibadan, Nigeria
| | - A. Akande
- IITA, PMB 82, Garki GPO, Kubwa, Abuja, Nigeria
| | - C. Mutegi
- IITA, ILRI campus, P.O. Box 30772-00100, Nairobi, Kenya
| | - J. Atehnkeng
- IITA, Chitedze Research Station, Off Mchinji Road, P.O. Box 30258, Lilongwe 3, Malawi
| | - L. Kaptoge
- International Institute of Tropical Agriculture (IITA), PMB 5320, Oyo Road, 200001 Ibadan, Nigeria
| | - A.L. Senghor
- La Direction de la Protection des Végétaux (DPV), Km 15, Route de Rufisque, en face Forail, BP 20054, Thiaroye-Dakar, Senegal
| | - B.N. Adhikari
- USDA-ARS, School of Plant Sciences, University of Arizona, P.O. Box 210036, Tucson, AZ 85721-0036, USA
| | - P.J. Cotty
- USDA-ARS, School of Plant Sciences, University of Arizona, P.O. Box 210036, Tucson, AZ 85721-0036, USA
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Wambui J, Karuri E, Ojiambo J, Njage P. Adaptation and mitigation options to manage aflatoxin contamination in food with a climate change perspective. WORLD MYCOTOXIN J 2016. [DOI: 10.3920/wmj2016.2109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Understanding the impact of climate change remains vital for food safety and public health. Of particular importance is the influence of climatic conditions on the growth of Aspergillus flavus and production of their toxins. Nevertheless, little is known about the actual impact of climate change on the issue. Setting up of relevant measures to manage the impact has therefore become a daunting task especially in developing nations. Therefore, this study aimed at providing adaptation and mitigation options to manage this risk with a special focus on Kenya where cases of aflatoxicosis have been recurrent. We used a systematic literature review of review and research articles, with limited searching but systematic screening to explore available qualitative and quantitative data. Projections from the data, showed that on average, a 58.9% increase of aflatoxin contamination in the Central and Western parts and a decrease of 44.6% in the Eastern and Southern parts is expected but with several possible scenarios. This makes the impact of climate change on aflatoxin contamination in Kenya complex. To protect the public and environment from the negative impact, a regulatory framework that allows for an integrated management of aflatoxins in a changing climate was proposed. The management practices in the framework are divided into agronomic, post-harvest and institutional levels. Given the multiple points of application, coordination amongst stakeholders along the chain is fundamental. We therefore proposed a complimentary framework that allows the food safety issues to be addressed in an integrated manner while allowing for transparent synergies and trade-offs (in implementing the measures). A policy-oriented foresight should be carried out to provide policy based evidence for the applicability of the proposed adaptation and mitigation measures.
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Affiliation(s)
- J.M. Wambui
- Department of Food Science, Nutrition and Technology, College of Agriculture and Veterinary Sciences, University of Nairobi, P.O. Box 29053, 00625 Nairobi, Kenya
- Kenya Nutritionists and Dieticians Institute, P.O. Box 20436, 00100 Nairobi, Kenya
| | - E.G. Karuri
- Department of Food Science, Nutrition and Technology, College of Agriculture and Veterinary Sciences, University of Nairobi, P.O. Box 29053, 00625 Nairobi, Kenya
| | - J.A. Ojiambo
- Kenya Nutritionists and Dieticians Institute, P.O. Box 20436, 00100 Nairobi, Kenya
| | - P.M.K. Njage
- Department of Food Science, Nutrition and Technology, College of Agriculture and Veterinary Sciences, University of Nairobi, P.O. Box 29053, 00625 Nairobi, Kenya
- Division for Epidemiology and Microbial Genomics, National Food Institute, Technical University of Denmark, Søltofts Plads, 2800 Kgs. Lyngby, Denmark
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Degeneration of aflatoxin gene clusters in Aspergillus flavus from Africa and North America. AMB Express 2016; 6:62. [PMID: 27576895 PMCID: PMC5005231 DOI: 10.1186/s13568-016-0228-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 08/12/2016] [Indexed: 01/07/2023] Open
Abstract
Aspergillus flavus is the most common causal agent of aflatoxin contamination of food and feed. However, aflatoxin-producing potential varies widely among A. flavus genotypes with many producing no aflatoxins. Some non-aflatoxigenic genotypes are used as biocontrol agents to prevent contamination. Aflatoxin biosynthesis genes are tightly clustered in a highly conserved order. Gene deletions and presence of single nucleotide polymorphisms (SNPs) in aflatoxin biosynthesis genes are often associated with A. flavus inability to produce aflatoxins. In order to identify mechanisms of non-aflatoxigenicity in non-aflatoxigenic genotypes of value in aflatoxin biocontrol, complete cluster sequences of 35 A. flavus genotypes from Africa and North America were analyzed. Inability of some genotypes to produce aflatoxin resulted from deletion of biosynthesis genes. In other genotypes, non-aflatoxigenicity originated from SNP formation. The process of degeneration differed across the gene cluster; genes involved in early biosynthesis stages were more likely to be deleted while genes involved in later stages displayed high frequencies of SNPs. Comparative analyses of aflatoxin gene clusters provides insight into the diversity of mechanisms of non-aflatoxigenicity in A. flavus genotypes used as biological control agents. The sequences provide resources for both diagnosis of non-aflatoxigenicity and monitoring of biocontrol genotypes during biopesticide manufacture and in the environment.
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Ortega‐Beltran A, Grubisha L, Callicott K, Cotty P. The vegetative compatibility group to which the
US
biocontrol agent
Aspergillus flavus
AF
36 belongs is also endemic to Mexico. J Appl Microbiol 2016; 120:986-98. [DOI: 10.1111/jam.13047] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Revised: 12/16/2015] [Accepted: 01/03/2016] [Indexed: 10/22/2022]
Affiliation(s)
| | - L.C. Grubisha
- Department of Natural and Applied Sciences University of Wisconsin‐Green Bay Green Bay WI USA
| | - K.A. Callicott
- USDA‐ARS School of Plant Sciences University of Arizona Tucson AZ USA
| | - P.J. Cotty
- USDA‐ARS School of Plant Sciences University of Arizona Tucson AZ USA
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Distribution of indigenous strains of atoxigenic and toxigenic Aspergillus flavus and Aspergillus parasiticus in maize and peanuts agro-ecological zones of Kenya. ACTA ACUST UNITED AC 2015. [DOI: 10.1186/s40066-015-0033-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Yabe K, Hatabayashi H, Ikehata A, Zheng Y, Kushiro M. Development of the dichlorvos-ammonia (DV-AM) method for the visual detection of aflatoxigenic fungi. Appl Microbiol Biotechnol 2015; 99:10681-94. [PMID: 26300294 DOI: 10.1007/s00253-015-6924-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Revised: 08/02/2015] [Accepted: 08/07/2015] [Indexed: 10/23/2022]
Abstract
Aflatoxins (AFs) are carcinogenic and toxic secondary metabolites produced mainly by Aspergillus flavus and Aspergillus parasiticus. To monitor and regulate the AF contamination of crops, a sensitive and precise detection method for these toxigenic fungi in environments is necessary. We herein developed a novel visual detection method, the dichlorvos-ammonia (DV-AM) method, for identifying AF-producing fungi using DV and AM vapor on agar culture plates, in which DV inhibits the esterase in AF biosynthesis, causing the accumulation of anthraquinone precursors (versiconal hemiacetal acetate and versiconol acetate) of AFs in mycelia on the agar plate, followed by a change in the color of the colonies from light yellow to brilliant purple-red by the AM vapor treatment. We also investigated the appropriate culture conditions to increase the color intensity. It should be noted that other species producing the same precursors of AFs such as Aspergillus nidulans and Aspergillus versicolor could be discriminated from the Aspergillus section Flavi based on the differences of their phenotypes. The DV-AM method was also useful for the isolation of nonaflatoxigenic fungi showing no color change, for screening microorganisms that inhibit the AF production by fungi, and for the characterization of the fungi infecting corn kernels. Thus, the DV-AM method can provide a highly sensitive and visible indicator for the detection of aflatoxigenic fungi.
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Affiliation(s)
- Kimiko Yabe
- National Food Research Institute, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, 305-8642, Japan.
- Department of Environmental and Food Sciences, Fukui University of Technology, 3-6-1, Gakuen, Fukui-shi, Fukui, 910-8505, Japan.
| | - Hidemi Hatabayashi
- National Food Research Institute, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, 305-8642, Japan
| | - Akifumi Ikehata
- National Food Research Institute, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, 305-8642, Japan
| | - Yazhi Zheng
- National Food Research Institute, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, 305-8642, Japan
| | - Masayo Kushiro
- National Food Research Institute, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, 305-8642, Japan
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Aflatoxin-producing fungi in maize field soils from sea level to over 2000 masl: a three year study in Sonora, Mexico. Fungal Biol 2014; 119:191-200. [PMID: 25813508 DOI: 10.1016/j.funbio.2014.12.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/09/2014] [Accepted: 12/10/2014] [Indexed: 11/21/2022]
Abstract
Aflatoxins, highly toxic carcinogens produced by several members of Aspergillus section Flavi, contaminate crops in temperate zones. In the state of Sonora, Mexico, maize is cultivated from 0 to 2100 masl with diverse cultivation practices. This is typical of the nation. In order to design better sampling strategies across Mexico, aflatoxin-producing fungal communities associated with maize production during 2006, 2007, and 2008 in Sonora were investigated in four agro-ecological zones (AEZ) at varying elevation. Fungal communities were dominated by the Aspergillus flavus L strain morphotype (46%), but variation occurred between years and among AEZ. Several atoxigenic isolates with potential to be used as biocontrol agents for aflatoxin mitigation were detected in all AEZ. The characteristics of each AEZ had minimal influences on fungal community structure and should not be a major consideration for future sampling designs for Mexico. Insights into the dynamics and stability of aflatoxin-producing fungal communities across AEZ are discussed.
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39
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Hamidi A, Mirnejad R, Yahaghi E, Behnod V, Mirhosseini A, Amani S, Sattari S, Darian EK. The aflatoxin B1 isolating potential of two lactic acid bacteria. Asian Pac J Trop Biomed 2014; 3:732-6. [PMID: 23998015 DOI: 10.1016/s2221-1691(13)60147-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 07/28/2013] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVE To determine lactic acid bacteria's capability to enhance the process of binding and isolating aflatoxin B1 and to utilize such lactic acid bacteria as a food supplement or probiotic products for preventing absorption of aflatoxin B1 in human and animal bodies. METHODS In the present research, the bacteria were isolated from five different sources. For surveying the capability of the bacteria in isolating aflatoxin B1, ELISA method was implemented, and for identifying the resultant strains through 16S rRNA sequencing method, universal primers were applied. RESULTS Among the strains which were isolated, two strains of Lactobacillus pentosus and Lactobacillus beveris exhibited the capability of absorbing and isolating aflatoxin B1 by respectively absorbing and discharging 17.4% and 34.7% of the aforementioned toxin existing in the experiment solution. CONCLUSIONS Strains of Lactobacillus pentosus and Lactobacillus beveris were isolated from human feces and local milk samples, respectively. And both strains has the ability to isolate or bind with aflatoxin B1.
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Affiliation(s)
- Adel Hamidi
- Department of Microbiology, Razi Vaccine and Serum Research Institute, Arak, Iran
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40
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Ehrlich KC. Non-aflatoxigenic Aspergillus flavus to prevent aflatoxin contamination in crops: advantages and limitations. Front Microbiol 2014; 5:50. [PMID: 24575088 PMCID: PMC3918586 DOI: 10.3389/fmicb.2014.00050] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 01/23/2014] [Indexed: 12/25/2022] Open
Abstract
Aspergillus flavus is a diverse assemblage of strains that include aflatoxin-producing and non-toxigenic strains with cosmopolitan distribution. The most promising strategy currently being used to reduce preharvest contamination of crops with aflatoxin is to introduce non-aflatoxin (biocontrol) A. flavus into the crop environment. Whether or not introduction of biocontrol strains into agricultural fields is enough to reduce aflatoxin contamination to levels required for acceptance of the contaminated food as fit for consumption is still unknown. There is no question that biocontrol strains are able to reduce the size of the populations of aflatoxin-producing strains but the available data suggests that at most only a four- to five-fold reduction in aflatoxin contamination is achieved. There are many challenges facing this strategy that are both short term and long term. First, the population biology of A. flavus is not well understood due in part to A. flavus's diversity, its ability to form heterokaryotic reproductive forms, and its unknown ability to survive for prolonged periods after application. Second, biocontrol strains must be selected that are suitable for the environment, the type of crop, and the soil into which they will be introduced. Third, there is a need to guard against inadvertent introduction of A. flavus strains that could impose an additional burden on food safety and food quality, and fourth, with global warming and resultant changes in the soil nutrients and concomitant microbiome populations, the biocontrol strategy must be sufficiently flexible to adapt to such changes. Understanding genetic variation within strains of A. flavus is important for developing a robust biocontrol strategy and it is unlikely that a "one size fits all" strategy will work for preharvest aflatoxin reduction.
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Affiliation(s)
- Kenneth C. Ehrlich
- Southern Regional Research Center, United States Department of Agriculture – Agricultural Research ServiceNew Orleans, LA, USA
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41
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McCormick SP. Microbial detoxification of mycotoxins. J Chem Ecol 2013; 39:907-18. [PMID: 23846184 DOI: 10.1007/s10886-013-0321-0] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 06/24/2013] [Accepted: 06/28/2013] [Indexed: 11/24/2022]
Abstract
Mycotoxins are fungal natural products that are toxic to vertebrate animals including humans. Microbes have been identified that enzymatically convert aflatoxin, zearalenone, ochratoxin, patulin, fumonisin, deoxynivalenol, and T-2 toxin to less toxic products. Mycotoxin-degrading fungi and bacteria have been isolated from agricultural soil, infested plant material, and animal digestive tracts. Biotransformation reactions include acetylation, glucosylation, ring cleavage, hydrolysis, deamination, and decarboxylation. Microbial mycotoxin degrading enzymes can be used as feed additives or to decontaminate agricultural commodities. Some detoxification genes have been expressed in plants to limit the pre-harvest mycotoxin production and to protect crop plants from the phytotoxic effects of mycotoxins. Toxin-deficient mutants may be useful in assessing the role of mycotoxins in the ecology of the microorganisms.
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Affiliation(s)
- Susan P McCormick
- Bacterial Foodborne Pathogens and Mycology Research Unit, USDA-ARS-NCAUR, Peoria, IL, 61604, USA.
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42
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Gnonlonfin GJB, Hell K, Adjovi Y, Fandohan P, Koudande DO, Mensah GA, Sanni A, Brimer L. A review on aflatoxin contamination and its implications in the developing world: a sub-Saharan African perspective. Crit Rev Food Sci Nutr 2013; 53:349-65. [PMID: 23320907 DOI: 10.1080/10408398.2010.535718] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Mycotoxins contamination in some agricultural food commodities seriously impact human and animal health and reduce the commercial value of crops. Mycotoxins are toxic secondary metabolites produced by fungi that contaminate agricultural commodities pre- or postharvest. Africa is one of the continents where environmental, agricultural and storage conditions of food commodities are conducive of Aspergillus fungi infection and aflatoxin biosynthesis. This paper reviews the commodity-wise aetiology and contamination process of aflatoxins and evaluates the potential risk of exposure from common African foods. Possible ways of reducing risk for fungal infection and aflatoxin development that are relevant to the African context. The presented database would be useful as benchmark information for development and prioritization of future research. There is need for more investigations on food quality and safety by making available advanced advanced equipments and analytical methods as well as surveillance and awareness creation in the region.
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Affiliation(s)
- G J B Gnonlonfin
- Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Denmark, Frederiksberg C, Denmark.
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Laboratory tests for assessing efficacy of atoxigenic Aspergillus flavus strains as biocontrol agents. Int J Food Microbiol 2011; 146:235-43. [DOI: 10.1016/j.ijfoodmicro.2011.02.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 12/13/2010] [Accepted: 02/20/2011] [Indexed: 11/21/2022]
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Probst C, Bandyopadhyay R, Price LE, Cotty PJ. Identification of Atoxigenic Aspergillus flavus Isolates to Reduce Aflatoxin Contamination of Maize in Kenya. PLANT DISEASE 2011; 95:212-218. [PMID: 30743416 DOI: 10.1094/pdis-06-10-0438] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Aspergillus flavus has two morphotypes, the S strain and the L strain, that differ in aflatoxin-producing ability and other characteristics. Fungal communities on maize dominated by the S strain of A. flavus have repeatedly been associated with acute aflatoxin poisonings in Kenya, where management tools to reduce aflatoxin levels in maize are needed urgently. A. flavus isolates (n = 290) originating from maize produced in Kenya and belonging to the L strain morphotype were tested for aflatoxin-producing potential. A total of 96 atoxigenic isolates was identified from four provinces sampled. The 96 atoxigenic isolates were placed into 53 vegetative compatibility groups (VCGs) through complementation of nitrate non-utilizing mutants. Isolates from each of 11 VCGs were obtained from more than one maize sample, isolates from 10 of the VCGs were detected in multiple districts, and isolates of four VCGs were found in multiple provinces. Atoxigenic isolates were tested for potential to reduce aflatoxin concentrations in viable maize kernels that were co-inoculated with highly toxigenic S strain isolates. The 12 most effective isolates reduced aflatoxin levels by >80%. Reductions in aflatoxin levels caused by the most effective Kenyan isolates were comparable with those achieved with a United States isolate (NRRL-21882) used commercially for aflatoxin management. This study identified atoxigenic isolates of A. flavus with potential value for biological control within highly toxic Aspergillus communities associated with maize production in Kenya. These atoxigenic isolates have potential value in mitigating aflatoxin outbreaks in Kenya, and should be evaluated under field conditions.
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Affiliation(s)
- C Probst
- The University of Arizona, School of Plant Sciences, Tucson 85721
| | - R Bandyopadhyay
- International Institute of Tropical Agriculture (IIITA), PMB 5320, Ibadan, Nigeria
| | - L E Price
- United States Department of Agriculture, Agricultural Research Service, The University of Arizona, School of Plant Sciences
| | - P J Cotty
- United States Department of Agriculture, Agricultural Research Service, The University of Arizona, School of Plant Sciences
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45
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Ehrlich K, Wei Q, Bhatnagar D. Increased sensitivity of Aspergillus flavus and Aspergillus parasiticus aflatoxin biosynthesis polyketide synthase mutants to UVB light. WORLD MYCOTOXIN J 2010. [DOI: 10.3920/wmj2010.1218] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
One strategy to reduce aflatoxin contamination of maize and cottonseed is to introduce spores of non-aflatoxigenic strains as competitors. Using isogenic mutants we show that, upon 5 or 20 min exposure to 302 nm (UVB) light, the viability of conidia of Aspergillus flavus and Aspergillus parasiticus mutants lacking the ability to accumulate any aflatoxin precursor metabolite is reduced five-fold compared to that of aflatoxin-producing strains or pigmented mutants that accumulate aflatoxin precursors. This result suggests that the long-term viability of introduced non-aflatoxigenic competitor strains may be lower than that of natural aflatoxin-producing isolates when exposed to sunlight.
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Affiliation(s)
- K. Ehrlich
- Southern Regional Research Center, ARS, USDA, 1100 Robert E. Lee Blvd, New Orleans, LA 70124, USA
| | - Q. Wei
- Southern Regional Research Center, ARS, USDA, 1100 Robert E. Lee Blvd, New Orleans, LA 70124, USA
| | - D. Bhatnagar
- Southern Regional Research Center, ARS, USDA, 1100 Robert E. Lee Blvd, New Orleans, LA 70124, USA
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46
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Ehrlich KC. Predicted roles of the uncharacterized clustered genes in aflatoxin biosynthesis. Toxins (Basel) 2009; 1:37-58. [PMID: 22069531 PMCID: PMC3202775 DOI: 10.3390/toxins1010037] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 09/22/2009] [Accepted: 09/24/2009] [Indexed: 11/21/2022] Open
Abstract
Biosynthesis of the toxic and carcinogenic aflatoxins (AFs) requires the activity of more than 27 enzymes. The roles in biosynthesis of newly described enzymes are discussed in this review. We suggest that HypC catalyzes the oxidation of norsolorinic acid anthrone; AvfA (AflI), the ring-closure step in formation of hydroxyversicolorone; HypB, the second oxidation step in conversion of O-methylsterigmatocystin to AF; and HypE and NorA (AflE), the final two steps in AFB(1) formation. HypD, an integral membrane protein, affects fungal development and lowers AF production while AflJ (AflS), has a partial methyltransferase domain that may be important in its function as a transcriptional co-activator.
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Affiliation(s)
- Kenneth C Ehrlich
- Southern Regional Research Center, ARS, USDA/1100 Robert E. Lee Blvd, New Orleans, LA 70124, USA.
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47
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Probst C, Schulthess F, Cotty PJ. Impact of Aspergillus section Flavi community structure on the development of lethal levels of aflatoxins in Kenyan maize (Zea mays). J Appl Microbiol 2009; 108:600-10. [PMID: 19674186 DOI: 10.1111/j.1365-2672.2009.04458.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS To evaluate the potential role of fungal community structure in predisposing Kenyan maize to severe aflatoxin contamination by contrasting aflatoxin-producing fungi resident in the region with repeated outbreaks of lethal aflatoxicosis to those in regions without a history of aflatoxicosis. METHODS AND RESULTS Fungi belonging to Aspergillus section Flavi were isolated from maize samples from three Kenyan provinces between 2004 and 2006. Frequencies of identified strains and aflatoxin-producing abilities were assessed, and the data were analysed by statistical means. Most aflatoxin-producing fungi belonged to Aspergillus flavus. The two major morphotypes of A. flavus varied greatly between provinces, with the S strain dominant in both soil and maize within aflatoxicosis outbreak regions and the L strain dominant in nonoutbreak regions. CONCLUSIONS Aspergillus community structure is an important factor in the development of aflatoxins in maize in Kenya and, as such, is a major contributor to the development of aflatoxicosis in the Eastern Province. SIGNIFICANCE AND IMPACT OF THE STUDY Since 1982, deaths caused by aflatoxin-contaminated maize have repeatedly occurred in the Eastern Province of Kenya. The current study characterized an unusual fungal community structure associated with the lethal contamination events. The results will be helpful in developing aflatoxin management practices to prevent future outbreaks in Kenya.
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Affiliation(s)
- C Probst
- Department of Plant Sciences, The University of Arizona, Tucson, Arizona, USA
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48
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Brown SH, Scott JB, Bhaheetharan J, Sharpee WC, Milde L, Wilson RA, Keller NP. Oxygenase coordination is required for morphological transition and the host-fungus interaction of Aspergillus flavus. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2009; 22:882-94. [PMID: 19522570 DOI: 10.1094/mpmi-22-7-0882] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Oxylipins, a class of oxygenase-derived unsaturated fatty acids, are important signal molecules in many biological systems. Recent characterization of an Aspergillus flavus lipoxygenase gene, lox, revealed its importance in maintaining a density-dependent morphology switch from sclerotia to conidia as population density increased. Here, we present evidence for the involvement of four more oxylipin-generating dioxygenases (PpoA, PpoB, PpoC, and PpoD) in A. flavus density-dependent phenomena and the effects of loss of these genes on aflatoxin production and seed colonization. Although several single mutants showed alterations in the sclerotia-to-conidia switch, the major effect was observed in a strain downregulated for all five oxygenases (invert repeat transgene [IRT] strain IRT4 = ppoA, ppoB, ppoC, ppoD, and lox). In strain IRT4, sclerotia production was increased up to 500-fold whereas conidiation was decreased down to 100-fold and the strain was unable to switch into conidial production. Aflatoxin (AF) production for all mutant strains and the wild type was greatest at low population densities and absent in high populations except for strain IRT4, which consistently produced high levels of the mycotoxin. Growth on host seed by both IRT4 and IRT2 (downregulated in ppoA, ppoB, and ppoD) was marked by decreased conidial but increased AF production. We propose that A. flavus oxygenases and the oxylipins they produce act in a highly interdependent network with some redundancy of biological function. These studies provide substantial evidence for oxylipin-based mechanisms in governing fungus-seed interactions and in regulating a coordinated quorum-sensing mechanism in A. flavus.
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Affiliation(s)
- Sigal Horowitz Brown
- Department of Plant Pathology, University of Wisconsin-Madison, Madison 53706-1598, USA
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