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Schamann A, Geisen R, Schmidt-Heydt M. Whole-genome sequence of an Aspergillus parasiticus strain isolated from Kenyan soil. Microbiol Resour Announc 2023; 12:e0020323. [PMID: 37462395 PMCID: PMC10508115 DOI: 10.1128/mra.00203-23] [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: 03/14/2023] [Accepted: 06/14/2023] [Indexed: 09/20/2023] Open
Abstract
Aspergillus parasiticus is an important aflatoxigenic fungus, frequently found in soil samples. Here, we report the sequencing of A. parasiticus strain MRI410 using Illumina MiSeq and Oxford Nanopore platforms. This strain was isolated from soil of a Kenyan maize field.
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Affiliation(s)
- Alexandra Schamann
- Department of Safety and Quality of Fruit and Vegetables, Max Rubner-Institut (MRI), Federal Research Institute of Nutrition and Food, Karlsruhe, Germany
| | - Rolf Geisen
- Department of Safety and Quality of Fruit and Vegetables, Max Rubner-Institut (MRI), Federal Research Institute of Nutrition and Food, Karlsruhe, Germany
| | - Markus Schmidt-Heydt
- Department of Safety and Quality of Fruit and Vegetables, Max Rubner-Institut (MRI), Federal Research Institute of Nutrition and Food, Karlsruhe, Germany
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2
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Schamann A, Geisen R, Schmidt-Heydt M. Whole-Genome Sequences of Two Kenyan Aspergillus minisclerotigenes Strains. Microbiol Resour Announc 2023; 12:e0021923. [PMID: 37404178 PMCID: PMC10443383 DOI: 10.1128/mra.00219-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 06/14/2023] [Indexed: 07/06/2023] Open
Abstract
Here, we report the sequencing of the whole genome, including the mitochondrial DNA, of the two highly aflatoxigenic Aspergillus minisclerotigenes strains MRI390 and MRI400 using the MiSeq and PacBio platforms and the generated assemblies. The strains were isolated from Kenyan maize kernels.
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Affiliation(s)
- Alexandra Schamann
- Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Fruit and Vegetables, Karlsruhe, Germany
| | - Rolf Geisen
- Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Fruit and Vegetables, Karlsruhe, Germany
| | - Markus Schmidt-Heydt
- Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Fruit and Vegetables, Karlsruhe, Germany
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3
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Saber H, Chebloune Y, Moussaoui A. Molecular Characterization of Aspergillus flavus Strains Isolated from Animal Feeds. Pol J Microbiol 2022; 71:589-599. [PMID: 36537059 PMCID: PMC9944975 DOI: 10.33073/pjm-2022-048] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 09/21/2022] [Indexed: 12/24/2022] Open
Abstract
Aflatoxin (AF)-producing fungi such as Aspergillus flavus commonly contaminate animal feeds, causing high economic losses. A. flavus is the most prevalent and produces AFB1, a potent mutagen, and carcinogen threatening human and animal health. Aspergillaceae is a large group of closely related fungi sharing number of morphological and genetic similarities that complicate the diagnosis of highly pathogenic strains. We used here morphological and molecular assays to characterize fungal isolates from animal feeds in Southwestern Algeria. These tools helped to identify 20 out of 30 Aspergillus strains, and 15 of them belonged to the Aspergillus section Flavi. Further analyses detected four out of 15 as belonging to Aspergillus flavus-parasiticus group. PCR targeting the AF genes' aflR-aflS(J) intergenic region amplified a single 674 bp amplicon in all four isolates. The amplicons were digested with a BglII endonuclease, and three specific fragments were observed for A. flavus but A. parasitucus lacked two typical fragments. Sequencing data of four amplicons confirmed the presence of the two BglII restriction sites yielding the three fragments, confirming that all four strains were A. flavus. In addition, this analysis illustrated the genetic variability within the A. flavus strains.
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Affiliation(s)
- Hadjer Saber
- Laboratory of Plant Resources Valorization and Food Safety in Semi-Arid Areas of Southwestern Algeria, Department of Biology, University of Bechar, Bechar, Algeria
| | - Yahia Chebloune
- USC 1450 INRAE/UGA Lentiviral Pathogenesis and Vaccination Laboratory, Department of Biology, University of Grenoble Alpes, Saint-Martin-d’Hères, France, Y. Chebloune, Lentiviral Pathogenesis and Vaccination Laboratory, PAVAL Lab., Department of Biology, University of Grenoble Alpes, Saint-Martin-d’Hères, France;
| | - Abdallah Moussaoui
- Laboratory of Plant Resources Valorization and Food Safety in Semi-Arid Areas of Southwestern Algeria, Department of Biology, University of Bechar, Bechar, Algeria
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4
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Silva JJ, Fungaro MHP, Wang X, Larsen TO, Frisvad JC, Taniwaki MH, Iamanaka BT. Deep Genotypic Species Delimitation of Aspergillus Section Flavi Isolated from Brazilian Foodstuffs and the Description of Aspergillus annui sp. nov. and Aspergillus saccharicola sp. nov. J Fungi (Basel) 2022; 8:1279. [PMID: 36547612 PMCID: PMC9781283 DOI: 10.3390/jof8121279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/25/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
Aspergillus section Flavi is a fungal group that is important in food because it contains spoilage and potentially aflatoxigenic species. Aflatoxins are metabolites that are harmful to human and animal health and have been recognized as the primary natural contaminant in food. Therefore, recognizing the biodiversity of this group in food is necessary to reduce risks to public health. Our study aimed to investigate the diversity of Aspergillus section Flavi isolated from Brazilian foodstuffs such as cassava, sugarcane, black pepper, paprika, Brazil nuts, yerba-mate, peanuts, rice, and corn. A polyphasic approach integrating phenotypic data and multilocus genotypic analyses (CaM, BenA, and RPB2) was performed for 396 strains. Two new species in the Aspergillus subgenus Circumdati section Flavi are proposed using maximum-likelihood analysis, Bayesian inference, and coalescence-based methods: Aspergillus saccharicola sp. nov. and Aspergillus annui sp. nov. A. saccharicola sp. nov. belongs to the series Flavi, is a potentially aflatoxigenic species (B1, B2, G1, and G2), closely related to Aspergillus arachidicola, and was found mostly in sugarcane. A. annui sp. nov. was isolated from samples of sweet paprika. To accommodate A. annui sp. nov., a new series Annuorum was proposed.
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Affiliation(s)
- Josué J. Silva
- Centro de Ciência e Qualidade de Alimentos, Instituto de Tecnologia de Alimentos, Campinas 13070-178, São Paulo, Brazil
| | - Maria H. P. Fungaro
- Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina 86057-970, Paraná, Brazil
| | - Xinhui Wang
- Department of Biotechnology and Biomedicine, DTU-Bioengineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Thomas O. Larsen
- Department of Biotechnology and Biomedicine, DTU-Bioengineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Jens C. Frisvad
- Department of Biotechnology and Biomedicine, DTU-Bioengineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Marta H. Taniwaki
- Centro de Ciência e Qualidade de Alimentos, Instituto de Tecnologia de Alimentos, Campinas 13070-178, São Paulo, Brazil
| | - Beatriz T. Iamanaka
- Centro de Ciência e Qualidade de Alimentos, Instituto de Tecnologia de Alimentos, Campinas 13070-178, São Paulo, Brazil
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Hleba L, Hlebova M, Kovacik A, Petrova J, Maskova Z, Cubon J, Massanyi P. Use of MALDI-TOF MS to Discriminate between Aflatoxin B1-Producing and Non-Producing Strains of Aspergillus flavus. Molecules 2022; 27:molecules27227861. [PMID: 36431961 PMCID: PMC9692738 DOI: 10.3390/molecules27227861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/09/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
Aflatoxin B1 (AFB1) is one of the most toxic mycotoxins. One of the producers of AFB1 is Aspergillus flavus. Therefore, its rapid identification plays a key role in various sectors of the food and feed industry. MALDI-TOF mass spectrometry is one of the fastest and most accurate methods today. Therefore, the aim of this research was to develop the rapid identification of producing and non-producing strains of A. flavus based on the entire mass spectrum. To accomplish the main goal a different confirmatory MALDI-TOF MS and TLC procedures such as direct AFB1 identification by scraping from TLC plates, A. flavus mycelium, nutrient media around A. flavus growth, and finally direct AFB1 identification from infected wheat and barley grains had to be conducted. In this experiment, MALDI-TOF mass spectrometry with various modifications was the main supporting technology. All confirmatory methods confirmed the presence of AFB1 in the samples of aflatoxin-producing strains of A. flavus and vice versa; AFB1 was not detected in the case of non-producing strains. Entire mass spectra (from 2 to 20 kDa) of aflatoxin-producing and non-producing A. flavus strains were collected, statistically analyzed and clustered. An in-depth analysis of the obtained entire mass spectra showed differences between AFB1-producing and non-producing strains of A. flavus. Statistical and cluster analysis divided AFB1-producing and non-producing strains of A. flavus into two monasteries. The results indicate that it is possible to distinguish between AFB1 producers and non-producers by comparing the entire mass spectra using MALDI-TOF MS. Finally, we demonstrated that if there are established local AFB1-producing and non-producing strains of A. flavus, the entire mass spectrum database identification of aflatoxigenic A. flavus strains can be even faster and cheaper, without the need to identify the toxin itself.
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Affiliation(s)
- Lukas Hleba
- Faculty of Biotechnology and Food Sciences, Institute of Biotechnology, Slovak University of Agriculture in Nitra, Tr. Andreja Hlinku 2, 949 76 Nitra, Slovakia
- Correspondence:
| | - Miroslava Hlebova
- Department of Biology, Faculty of Natural Sciences, University of Ss. Cyril and Methodius, Nám. J. Herdu 2, 917 01 Trnava, Slovakia
| | - Anton Kovacik
- Faculty of Biotechnology and Food Sciences, Institute of Applied Biology, Slovak University of Agriculture in Nitra, Tr. Andreja Hlinku 2, 949 76 Nitra, Slovakia
| | - Jana Petrova
- Faculty of Biotechnology and Food Sciences, Institute of Biotechnology, Slovak University of Agriculture in Nitra, Tr. Andreja Hlinku 2, 949 76 Nitra, Slovakia
| | - Zuzana Maskova
- Faculty of Biotechnology and Food Sciences, Institute of Biotechnology, Slovak University of Agriculture in Nitra, Tr. Andreja Hlinku 2, 949 76 Nitra, Slovakia
| | - Juraj Cubon
- Faculty of Biotechnology and Food Sciences, Institute of Food Sciences, Slovak University of Agriculture in Nitra, Tr. Andreja Hlinku 2, 949 76 Nitra, Slovakia
| | - Peter Massanyi
- Faculty of Biotechnology and Food Sciences, Institute of Applied Biology, Slovak University of Agriculture in Nitra, Tr. Andreja Hlinku 2, 949 76 Nitra, Slovakia
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Sweany RR, DeRobertis CD, Kaller MD, Damann KE. Intraspecific Growth and Aflatoxin Inhibition Responses to Atoxigenic Aspergillus flavus: Evidence of Secreted, Inhibitory Substances in Biocontrol. PHYTOPATHOLOGY 2022; 112:2084-2098. [PMID: 35502929 DOI: 10.1094/phyto-01-21-0022-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The fungus Aspergillus flavus infects corn, peanut, and cottonseed, and contaminates seeds with acutely poisonous and carcinogenic aflatoxin. Aflatoxin contamination is a perennial threat in tropical and subtropical climates. Nonaflatoxin-producing isolates (atoxigenic) are deployed in fields to mitigate aflatoxin contamination. The biocontrol competitively excludes toxigenic A. flavus via direct replacement and thigmoregulated (touch) toxin inhibition mechanisms. To understand the broad-spectrum toxin inhibition, toxigenic isolates representing different mating types and sclerotia sizes were individually cocultured with different atoxigenic biocontrol isolates. To determine whether more inhibitory isolates had a competitive advantage to displace or touch inhibit toxigenic isolates, biomass accumulation rates were determined for each isolate. Finally, to determine whether atoxigenic isolates could inhibit aflatoxin production without touch, atoxigenic isolates were grown separated from a single toxigenic isolate by a membrane. Atoxigenic isolates 17, Af36, and K49 had superior abilities to inhibit toxin production. Small (<400 µm) sclerotial, Mat1-1 isolates were not as completely inhibited as others by most atoxigenic isolates. As expected for both direct replacement and touch inhibition, the fastest-growing atoxigenic isolates inhibited aflatoxin production the most, except for atoxigenic Af36 and K49. Aflatoxin production was inhibited when toxigenic and atoxigenic isolates were grown separately, especially by slow-growing atoxigenic Af36 and K49. Additionally, fungus-free filtrates from atoxigenic cultures inhibited aflatoxin production. Toxin production inhibition without direct contact revealed secretion of diffusible chemicals as an additional biocontrol mechanism. Biocontrol formulations should be improved by identifying isolates with broad-spectrum, high-inhibition capabilities and production of secreted inhibitory chemicals.
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Affiliation(s)
- Rebecca R Sweany
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803
| | - Catherine D DeRobertis
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803
| | - Michael D Kaller
- School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, LA 70803
| | - Kenneth E Damann
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803
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Shabeer S, Asad S, Jamal A, Ali A. Aflatoxin Contamination, Its Impact and Management Strategies: An Updated Review. Toxins (Basel) 2022; 14:307. [PMID: 35622554 PMCID: PMC9147583 DOI: 10.3390/toxins14050307] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 04/21/2022] [Accepted: 04/21/2022] [Indexed: 01/10/2023] Open
Abstract
Aflatoxin, a type of mycotoxin, is mostly produced by Aspergillus flavus and Aspergillus parasiticus. It is responsible for the loss of billions of dollars to the world economy, by contaminating different crops such as cotton, groundnut, maize, and chilies, and causing immense effects on the health of humans and animals. More than eighteen different types of aflatoxins have been reported to date, and among them, aflatoxins B1, B2, G1, and G2 are the most prevalent and lethal. Early detection of fungal infection plays a key role in the control of aflatoxin contamination. Therefore, different methods, including culture, chromatographic techniques, and molecular assays, are used to determine aflatoxin contamination in crops and food products. Many countries have set a maximum limit of aflatoxin contamination (2-20 ppb) in their food and agriculture commodities for human or animal consumption, and the use of different methods to combat this menace is essential. Fungal infection mostly takes place during the pre- and post-harvest stage of crops, and most of the methods to control aflatoxin are employed for the latter phase. Studies have shown that if correct measures are adopted during the crop development phase, aflatoxin contamination can be reduced by a significant level. Currently, the use of bio-pesticides is the intervention employed in many countries, whereby atoxigenic strains competitively reduce the burden of toxigenic strains in the field, thereby helping to mitigate this problem. This updated review on aflatoxins sheds light on the sources of contamination, and the on occurrence, impact, detection techniques, and management strategies, with a special emphasis on bio-pesticides to control aflatoxins.
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Affiliation(s)
- Saba Shabeer
- Crop Diseases Research Institute, National Agricultural Research Centre, Park Road, Islamabad 45500, Pakistan; (S.S.); (S.A.)
| | - Shahzad Asad
- Crop Diseases Research Institute, National Agricultural Research Centre, Park Road, Islamabad 45500, Pakistan; (S.S.); (S.A.)
| | - Atif Jamal
- Crop Diseases Research Institute, National Agricultural Research Centre, Park Road, Islamabad 45500, Pakistan; (S.S.); (S.A.)
| | - Akhtar Ali
- Department of Biological Science, The University of Tulsa, Tulsa, OK 74104, USA
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Arias RS, Orner VA, Martinez-Castillo J, Sobolev VS. Aspergillus Section Flavi, Need for a Robust Taxonomy. Microbiol Resour Announc 2021; 10:e0078421. [PMID: 34854700 PMCID: PMC8638576 DOI: 10.1128/mra.00784-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Renee S. Arias
- USDA Agricultural Research Service, National Peanut Research Laboratory, Dawson, Georgia, USA
| | - Valerie A. Orner
- USDA Agricultural Research Service, National Peanut Research Laboratory, Dawson, Georgia, USA
| | - Jaime Martinez-Castillo
- Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán A. C., Mérida, Yucatán, Mexico
| | - Victor S. Sobolev
- USDA Agricultural Research Service, National Peanut Research Laboratory, Dawson, Georgia, USA
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Sweany RR, Mack BM, Moore GG, Gilbert MK, Cary JW, Lebar MD, Rajasekaran K, Damann Jr. KE. Genetic Responses and Aflatoxin Inhibition during Co-Culture of Aflatoxigenic and Non-Aflatoxigenic Aspergillus flavus. Toxins (Basel) 2021; 13:794. [PMID: 34822579 PMCID: PMC8618995 DOI: 10.3390/toxins13110794] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/30/2021] [Accepted: 11/05/2021] [Indexed: 11/16/2022] Open
Abstract
Aflatoxin is a carcinogenic mycotoxin produced by Aspergillus flavus. Non-aflatoxigenic (Non-tox) A. flavus isolates are deployed in corn fields as biocontrol because they substantially reduce aflatoxin contamination via direct replacement and additionally via direct contact or touch with toxigenic (Tox) isolates and secretion of inhibitory/degradative chemicals. To understand touch inhibition, HPLC analysis and RNA sequencing examined aflatoxin production and gene expression of Non-tox isolate 17 and Tox isolate 53 mono-cultures and during their interaction in co-culture. Aflatoxin production was reduced by 99.7% in 72 h co-cultures. Fewer than expected unique reads were assigned to Tox 53 during co-culture, indicating its growth and/or gene expression was inhibited in response to Non-tox 17. Predicted secreted proteins and genes involved in oxidation/reduction were enriched in Non-tox 17 and co-cultures compared to Tox 53. Five secondary metabolite (SM) gene clusters and kojic acid synthesis genes were upregulated in Non-tox 17 compared to Tox 53 and a few were further upregulated in co-cultures in response to touch. These results suggest Non-tox strains can inhibit growth and aflatoxin gene cluster expression in Tox strains through touch. Additionally, upregulation of other SM genes and redox genes during the biocontrol interaction demonstrates a potential role of inhibitory SMs and antioxidants as additional biocontrol mechanisms and deserves further exploration to improve biocontrol formulations.
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Affiliation(s)
- Rebecca R. Sweany
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Brian M. Mack
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Geromy G. Moore
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Matthew K. Gilbert
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Jeffrey W. Cary
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Matthew D. Lebar
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Kanniah Rajasekaran
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Kenneth E. Damann Jr.
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
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A review of mycotoxin biosynthetic pathways: associated genes and their expressions under the influence of climatic factors. FUNGAL BIOL REV 2021. [DOI: 10.1016/j.fbr.2021.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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11
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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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12
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Ching'anda C, Atehnkeng J, Bandyopadhyay R, Callicott KA, Orbach MJ, Mehl HL, Cotty PJ. Temperature Influences on Interactions Among Aflatoxigenic Species of Aspergillus Section Flavi During Maize Colonization. FRONTIERS IN FUNGAL BIOLOGY 2021; 2:720276. [PMID: 37744097 PMCID: PMC10512225 DOI: 10.3389/ffunb.2021.720276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/26/2021] [Indexed: 09/26/2023]
Abstract
Fungal species within Aspergillus section Flavi contaminate food and feed with aflatoxins. These toxic fungal metabolites compromise human and animal health and disrupt trade. Genotypically and phenotypically diverse species co-infect crops, but temporal and spatial variation in frequencies of different lineages suggests that environmental factors such as temperature may influence structure of aflatoxin-producing fungal communities. Furthermore, though most species within Aspergillus section Flavi produce sclerotia, divergent sclerotial morphologies (small or S-type sclerotia vs. large or L-type sclerotia) and differences in types and quantities of aflatoxins produced suggest lineages are adapted to different life strategies. Temperature is a key parameter influencing pre- and post-harvest aflatoxin contamination of crops. We tested the hypothesis that species of aflatoxin-producing fungi that differ in sclerotial morphology will vary in competitive ability and that outcomes of competition and aflatoxin production will be modulated by temperature. Paired competition experiments between highly aflatoxigenic S-type species (A. aflatoxiformans and Lethal Aflatoxicosis Fungus) and L-type species (A. flavus L morphotype and A. parasiticus) were conducted on maize kernels at 25 and 30°C. Proportions of each isolate growing within and sporulating on kernels were measured using quantitative pyrosequencing. At 30°C, S-type fungi were more effective at host colonization compared to L-type isolates. Total aflatoxins and the proportion of B vs. G aflatoxins were greater at 30°C compared to 25°C. Sporulation by L-type isolates was reduced during competition with S-type fungi at 30°C, while relative quantities of conidia produced by S-type species either increased or did not change during competition. Results indicate that both species interactions and temperature can shape population structure of Aspergillus section Flavi, with warmer temperatures favoring growth and dispersal of highly toxigenic species with S-type sclerotia.
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Affiliation(s)
- Connel Ching'anda
- School of Plant Sciences, University of Arizona, Tucson, AZ, United States
| | - Joseph Atehnkeng
- International Institute of Tropical Agriculture (IITA), Lilongwe, Malawi
| | | | - Kenneth A. Callicott
- United States Department of Agriculture - Agriculture Research Service, Tucson, AZ, United States
| | - Marc J. Orbach
- School of Plant Sciences, University of Arizona, Tucson, AZ, United States
| | - Hillary L. Mehl
- United States Department of Agriculture - Agriculture Research Service, Tucson, AZ, United States
| | - Peter J. Cotty
- School of Plant Sciences, University of Arizona, Tucson, AZ, United States
- United States Department of Agriculture - Agriculture Research Service, Tucson, AZ, United States
- College of Food Science and Engineering, Ocean University of China, Qingdao, China
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Pickova D, Ostry V, Toman J, Malir F. Aflatoxins: History, Significant Milestones, Recent Data on Their Toxicity and Ways to Mitigation. Toxins (Basel) 2021; 13:399. [PMID: 34205163 PMCID: PMC8227755 DOI: 10.3390/toxins13060399] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/04/2021] [Accepted: 06/02/2021] [Indexed: 02/07/2023] Open
Abstract
In the early 1960s the discovery of aflatoxins began when a total of 100,000 turkey poults died by hitherto unknown turkey "X" disease in England. The disease was associated with Brazilian groundnut meal affected by Aspergillus flavus. The toxin was named Aspergillus flavus toxin-aflatoxin. From the point of view of agriculture, aflatoxins show the utmost importance. Until now, a total of 20 aflatoxins have been described, with B1, B2, G1, and G2 aflatoxins being the most significant. Contamination by aflatoxins is a global health problem. Aflatoxins pose acutely toxic, teratogenic, immunosuppressive, carcinogenic, and teratogenic effects. Besides food insecurity and human health, aflatoxins affect humanity at different levels, such as social, economical, and political. Great emphasis is placed on aflatoxin mitigation using biocontrol methods. Thus, this review is focused on aflatoxins in terms of historical development, the principal milestones of aflatoxin research, and recent data on their toxicity and different ways of mitigation.
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Affiliation(s)
- Darina Pickova
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (J.T.); (F.M.)
| | - Vladimir Ostry
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (J.T.); (F.M.)
- Center for Health, Nutrition and Food in Brno, National Institute of Public Health in Prague, Palackeho 3a, CZ-61242 Brno, Czech Republic
| | - Jakub Toman
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (J.T.); (F.M.)
| | - Frantisek Malir
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (J.T.); (F.M.)
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14
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Microevolution in the pansecondary metabolome of Aspergillus flavus and its potential macroevolutionary implications for filamentous fungi. Proc Natl Acad Sci U S A 2021; 118:2021683118. [PMID: 34016748 DOI: 10.1073/pnas.2021683118] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Fungi produce a wealth of pharmacologically bioactive secondary metabolites (SMs) from biosynthetic gene clusters (BGCs). It is common practice for drug discovery efforts to treat species' secondary metabolomes as being well represented by a single or a small number of representative genomes. However, this approach misses the possibility that intraspecific population dynamics, such as adaptation to environmental conditions or local microbiomes, may harbor novel BGCs that contribute to the overall niche breadth of species. Using 94 isolates of Aspergillus flavus, a cosmopolitan model fungus, sampled from seven states in the United States, we dereplicate 7,821 BGCs into 92 unique BGCs. We find that more than 25% of pangenomic BGCs show population-specific patterns of presence/absence or protein divergence. Population-specific BGCs make up most of the accessory-genome BGCs, suggesting that different ecological forces that maintain accessory genomes may be partially mediated by population-specific differences in secondary metabolism. We use ultra-high-performance high-resolution mass spectrometry to confirm that these genetic differences in BGCs also result in chemotypic differences in SM production in different populations, which could mediate ecological interactions and be acted on by selection. Thus, our results suggest a paradigm shift that previously unrealized population-level reservoirs of SM diversity may be of significant evolutionary, ecological, and pharmacological importance. Last, we find that several population-specific BGCs from A. flavus are present in Aspergillus parasiticus and Aspergillus minisclerotigenes and discuss how the microevolutionary patterns we uncover inform macroevolutionary inferences and help to align fungal secondary metabolism with existing evolutionary theory.
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15
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Pickova D, Ostry V, Malir F. A Recent Overview of Producers and Important Dietary Sources of Aflatoxins. Toxins (Basel) 2021; 13:186. [PMID: 33802572 PMCID: PMC7998637 DOI: 10.3390/toxins13030186] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 02/22/2021] [Accepted: 02/26/2021] [Indexed: 02/06/2023] Open
Abstract
Aflatoxins (AFs) are some of the most agriculturally important and harmful mycotoxins. At least 20 AFs have been identified to this date. Aflatoxin B1 (AFB1), the most potent fungal toxin, can cause toxicity in many species, including humans. AFs are produced by 22 species of Aspergillus section Flavi, 4 species of A. section Nidulantes, and 2 species of A. section Ochraceorosei. The most important and well-known AF-producing species of section Flavi are Aspergillus flavus, A. parasiticus, and A. nomius. AFs contaminate a wide range of crops (mainly groundnuts, pistachio nuts, dried figs, hazelnuts, spices, almonds, rice, melon seeds, Brazil nuts, and maize). Foods of animal origin (milk and animal tissues) are less likely contributors to human AF exposure. Despite the efforts to mitigate the AF concentrations in foods, and thus enhance food safety, AFs continue to be present, even at high levels. AFs thus remain a current and continuously pressing problem in the world.
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Affiliation(s)
- Darina Pickova
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (F.M.)
| | - Vladimir Ostry
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (F.M.)
- Center for Health, Nutrition and Food in Brno, National Institute of Public Health in Prague, Palackeho 3a, CZ-61242 Brno, Czech Republic
| | - Frantisek Malir
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (F.M.)
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16
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Bhattarai K, Bhattarai K, Kabir ME, Bastola R, Baral B. Fungal natural products galaxy: Biochemistry and molecular genetics toward blockbuster drugs discovery. ADVANCES IN GENETICS 2021; 107:193-284. [PMID: 33641747 DOI: 10.1016/bs.adgen.2020.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Secondary metabolites synthesized by fungi have become a precious source of inspiration for the design of novel drugs. Indeed, fungi are prolific producers of fascinating, diverse, structurally complex, and low-molecular-mass natural products with high therapeutic leads, such as novel antimicrobial compounds, anticancer compounds, immunosuppressive agents, among others. Given that these microorganisms possess the extraordinary capacity to secrete diverse chemical scaffolds, they have been highly exploited by the giant pharma companies to generate small molecules. This has been made possible because the isolation of metabolites from fungal natural sources is feasible and surpasses the organic synthesis of compounds, which otherwise remains a significant bottleneck in the drug discovery process. Here in this comprehensive review, we have discussed recent studies on different fungi (pathogenic, non-pathogenic, commensal, and endophytic/symbiotic) from different habitats (terrestrial and marines), the specialized metabolites they biosynthesize, and the drugs derived from these specialized metabolites. Moreover, we have unveiled the logic behind the biosynthesis of vital chemical scaffolds, such as NRPS, PKS, PKS-NRPS hybrid, RiPPS, terpenoids, indole alkaloids, and their genetic mechanisms. Besides, we have provided a glimpse of the concept behind mycotoxins, virulence factor, and host immune response based on fungal infections.
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Affiliation(s)
- Keshab Bhattarai
- Pharmaceutical Institute, Department of Pharmaceutical Biology, University of Tübingen, Tübingen, Germany
| | - Keshab Bhattarai
- Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Md Ehsanul Kabir
- Animal Health Research Division, Bangladesh Livestock Research Institute, Savar, Dhaka, Bangladesh
| | - Rina Bastola
- Spinal Cord Injury Association-Nepal (SCIAN), Pokhara, Nepal
| | - Bikash Baral
- Department of Biochemistry, University of Turku, Turku, Finland.
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17
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Uka V, Cary JW, Lebar MD, Puel O, De Saeger S, Diana Di Mavungu J. Chemical repertoire and biosynthetic machinery of the Aspergillus flavus secondary metabolome: A review. Compr Rev Food Sci Food Saf 2020; 19:2797-2842. [PMID: 33337039 DOI: 10.1111/1541-4337.12638] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 12/18/2022]
Abstract
Filamentous fungi represent a rich source of extrolites, including secondary metabolites (SMs) comprising a great variety of astonishing structures and interesting bioactivities. State-of-the-art techniques in genome mining, genetic manipulation, and secondary metabolomics have enabled the scientific community to better elucidate and more deeply appreciate the genetic and biosynthetic chemical arsenal of these microorganisms. Aspergillus flavus is best known as a contaminant of food and feed commodities and a producer of the carcinogenic family of SMs, aflatoxins. This fungus produces many SMs including polyketides, ribosomal and nonribosomal peptides, terpenoids, and other hybrid molecules. This review will discuss the chemical diversity, biosynthetic pathways, and biological/ecological role of A. flavus SMs, as well as their significance concerning food safety and security.
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Affiliation(s)
- Valdet Uka
- Center of Excellence in Mycotoxicology and Public Health, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium.,Division of Pharmacy, Faculty of Medicine, University of Pristina, Pristina, Kosovo
| | - Jeffrey W Cary
- Southern Regional Research Center, USDA-ARS, New Orleans, Louisiana
| | - Matthew D Lebar
- Southern Regional Research Center, USDA-ARS, New Orleans, Louisiana
| | - Olivier Puel
- Toxalim (Research Centre in Food Toxicology), INRAE, ENVT, INP-Purpan, UPS, Université de Toulouse, Toulouse, France
| | - Sarah De Saeger
- Center of Excellence in Mycotoxicology and Public Health, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
| | - José Diana Di Mavungu
- Center of Excellence in Mycotoxicology and Public Health, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
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18
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Singh P, Mehl HL, Orbach MJ, Callicott KA, Cotty PJ. Phenotypic Differentiation of Two Morphologically Similar Aflatoxin-Producing Fungi from West Africa. Toxins (Basel) 2020; 12:toxins12100656. [PMID: 33066284 PMCID: PMC7602060 DOI: 10.3390/toxins12100656] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/10/2020] [Accepted: 10/11/2020] [Indexed: 11/16/2022] Open
Abstract
Aflatoxins (AF) are hepatocarcinogenic metabolites produced by several Aspergillus species. Crop infection by these species results in aflatoxin contamination of cereals, nuts, and spices. Etiology of aflatoxin contamination is complicated by mixed infections of multiple species with similar morphology and aflatoxin profiles. The current study investigates variation in aflatoxin production between two morphologically similar species that co-exist in West Africa, A. aflatoxiformans and A. minisclerotigenes. Consistent distinctions in aflatoxin production during liquid fermentation were discovered between these species. The two species produced similar concentrations of AFB1 in defined media with either urea or ammonium as the sole nitrogen source. However, production of both AFB1 and AFG1 were inhibited (p < 0.001) for A. aflatoxiformans in a yeast extract medium with sucrose. Although production of AFG1 by both species was similar in urea, A. minisclerotigenes produced greater concentrations of AFG1 in ammonium (p = 0.039). Based on these differences, a reliable and convenient assay for differentiating the two species was designed. This assay will be useful for identifying specific etiologic agents of aflatoxin contamination episodes in West Africa and other regions where the two species are sympatric, especially when phylogenetic analyses based on multiple gene segments are not practical.
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Affiliation(s)
- Pummi Singh
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, USA; (P.S.); (M.J.O.)
| | - Hillary L. Mehl
- USDA-ARS, 416 W Congress St, First Floor, Tucson, AZ 85701, USA;
- Correspondence: (H.L.M.); (P.J.C.)
| | - Marc J. Orbach
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, USA; (P.S.); (M.J.O.)
| | | | - Peter J. Cotty
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, USA; (P.S.); (M.J.O.)
- USDA-ARS, 416 W Congress St, First Floor, Tucson, AZ 85701, USA;
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
- Correspondence: (H.L.M.); (P.J.C.)
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19
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Drott MT, Satterlee TR, Skerker JM, Pfannenstiel BT, Glass NL, Keller NP, Milgroom MG. The Frequency of Sex: Population Genomics Reveals Differences in Recombination and Population Structure of the Aflatoxin-Producing Fungus Aspergillus flavus. mBio 2020; 11:e00963-20. [PMID: 32665272 PMCID: PMC7360929 DOI: 10.1128/mbio.00963-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/18/2020] [Indexed: 11/20/2022] Open
Abstract
The apparent rarity of sex in many fungal species has raised questions about how much sex is needed to purge deleterious mutations and how differences in frequency of sex impact fungal evolution. We sought to determine how differences in the extent of recombination between populations of Aspergillus flavus impact the evolution of genes associated with the synthesis of aflatoxin, a notoriously potent carcinogen. We sequenced the genomes of, and quantified aflatoxin production in, 94 isolates of A. flavus sampled from seven states in eastern and central latitudinal transects of the United States. The overall population is subdivided into three genetically differentiated populations (A, B, and C) that differ greatly in their extent of recombination, diversity, and aflatoxin-producing ability. Estimates of the number of recombination events and linkage disequilibrium decay suggest relatively frequent sex only in population A. Population B is sympatric with population A but produces significantly less aflatoxin and is the only population where the inability of nonaflatoxigenic isolates to produce aflatoxin was explained by multiple gene deletions. Population expansion evident in population B suggests a recent introduction or range expansion. Population C is largely nonaflatoxigenic and restricted mainly to northern sampling locations through restricted migration and/or selection. Despite differences in the number and type of mutations in the aflatoxin gene cluster, codon optimization and site frequency differences in synonymous and nonsynonymous mutations suggest that low levels of recombination in some A. flavus populations are sufficient to purge deleterious mutations.IMPORTANCE Differences in the relative frequencies of sexual and asexual reproduction have profound implications for the accumulation of deleterious mutations (Muller's ratchet), but little is known about how these differences impact the evolution of ecologically important phenotypes. Aspergillus flavus is the main producer of aflatoxin, a notoriously potent carcinogen that often contaminates food. We investigated if differences in the levels of production of aflatoxin by A. flavus could be explained by the accumulation of deleterious mutations due to a lack of recombination. Despite differences in the extent of recombination, variation in aflatoxin production is better explained by the demography and history of specific populations and may suggest important differences in the ecological roles of aflatoxin among populations. Furthermore, the association of aflatoxin production and populations provides a means of predicting the risk of aflatoxin contamination by determining the frequencies of isolates from low- and high-production populations.
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Affiliation(s)
- Milton T Drott
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Tatum R Satterlee
- Department of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jeffrey M Skerker
- Innovative Genomics Institute, The University of California, Berkeley, California, USA
| | | | - N Louise Glass
- Innovative Genomics Institute, The University of California, Berkeley, California, USA
- Department of Plant and Microbial Biology, The University of California, Berkeley, California, USA
- Environmental Genomics and Systems Biology, The Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Michael G Milgroom
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, New York, USA
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20
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Singh P, Callicott KA, Orbach MJ, Cotty PJ. Molecular Analysis of S-morphology Aflatoxin Producers From the United States Reveals Previously Unknown Diversity and Two New Taxa. Front Microbiol 2020; 11:1236. [PMID: 32625180 PMCID: PMC7315800 DOI: 10.3389/fmicb.2020.01236] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 05/14/2020] [Indexed: 01/12/2023] Open
Abstract
Aflatoxins are highly toxic carcinogens that detrimentally influence profitability of agriculture and the health of humans and domestic animals. Several phylogenetically distinct fungi within Aspergillus section Flavi have S-morphology (average sclerotial size < 400 μm), and consistently produce high concentrations of aflatoxins in crops. S-morphology fungi have been implicated as important etiologic agents of aflatoxin contamination in the United States (US), but little is known about the diversity of these fungi. The current study characterized S-morphology fungi (n = 494) collected between 2002 and 2017, from soil and maize samples, in US regions where aflatoxin contamination is a perennial problem. Phylogenetic analyses based on sequences of the calmodulin (1.9 kb) and nitrate reductase (2.1 kb) genes resolved S-morphology isolates from the US into four distinct clades: (1) Aspergillus flavus S-morphotype (89.7%); (2) Aspergillus agricola sp. nov. (2.4%); (3) Aspergillus texensis (2.2%); and (4) Aspergillus toxicus sp. nov. (5.7%). All four S-morphology species produced high concentrations of aflatoxins in maize at 25, 30, and 35°C, but only the A. flavus S-morphotype produced unacceptable aflatoxin concentrations at 40°C. Genetic typing of A. flavus S isolates using 17 simple sequence repeat markers revealed high genetic diversity, with 202 haplotypes from 443 isolates. Knowledge of the occurrence of distinct species and haplotypes of S-morphology fungi that are highly aflatoxigenic under a range of environmental conditions may provide insights into the etiology, epidemiology, and management of aflatoxin contamination in North America.
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Affiliation(s)
- Pummi Singh
- School of Plant Sciences, The University of Arizona, Tucson, AZ, United States
| | - Kenneth A. Callicott
- United States Department of Agriculture, Agricultural Research Service, Tucson, AZ, United States
| | - Marc J. Orbach
- School of Plant Sciences, The University of Arizona, Tucson, AZ, United States
| | - Peter J. Cotty
- School of Food Science and Engineering, Ocean University of China, Qingdao, China
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21
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Del Palacio A, Pan D. Occurrence and toxigenic potential of Aspergillus section Flavi on wheat and sorghum silages in Uruguay. Mycology 2020; 11:147-157. [PMID: 32923022 PMCID: PMC7448941 DOI: 10.1080/21501203.2020.1752321] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Species belonging to Aspergillus section Flavi occur naturally in crops and can cause food spoilage and/or toxin production. The aim of this study was to determine the occurrence and diversity of the species of Aspergillus section Flavi found in wheat and sorghum at harvest time and during silage storage, and to evaluate the toxigenic potential of the isolates to determine the contamination risk of mycotoxins in grains. Strains from Aspergillus flavus and Aspergillus parasiticus were found based on multi-gene phylogenetic analyses. This is the first report on the presence of A. parasiticus in wheat from Uruguay. Of the 80 isolates Aspergillus section Flavi, 30% produced aflatoxins (AFs), mainly type B1, and 25% produced cyclopiazonic acid (CPA). Within the isolates from wheat samples, 35% were AFs producers and 27.5% were CPA producers. Among the Aspergillus section Flavi isolates from sorghum, 25% were AFs producers while 22.5% were CPA producers. This work contributes to the knowledge of the species in crops and helps define appropriate strategies for the prevention and control of contamination with AFs and CPA by Aspergillus section Flavi fungi.
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Affiliation(s)
- Agustina Del Palacio
- Laboratorio de Micología, Facultad de Ciencias, Facultad de Ingeniería, UdelaR, Montevideo, Uruguay
| | - Dinorah Pan
- Laboratorio de Micología, Facultad de Ciencias, Facultad de Ingeniería, UdelaR, Montevideo, Uruguay
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22
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Houbraken J, Kocsubé S, Visagie C, Yilmaz N, Wang XC, Meijer M, Kraak B, Hubka V, Bensch K, Samson R, Frisvad J. Classification of Aspergillus, Penicillium, Talaromyces and related genera ( Eurotiales): An overview of families, genera, subgenera, sections, series and species. Stud Mycol 2020; 95:5-169. [PMID: 32855739 PMCID: PMC7426331 DOI: 10.1016/j.simyco.2020.05.002] [Citation(s) in RCA: 264] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The Eurotiales is a relatively large order of Ascomycetes with members frequently having positive and negative impact on human activities. Species within this order gain attention from various research fields such as food, indoor and medical mycology and biotechnology. In this article we give an overview of families and genera present in the Eurotiales and introduce an updated subgeneric, sectional and series classification for Aspergillus and Penicillium. Finally, a comprehensive list of accepted species in the Eurotiales is given. The classification of the Eurotiales at family and genus level is traditionally based on phenotypic characters, and this classification has since been challenged using sequence-based approaches. Here, we re-evaluated the relationships between families and genera of the Eurotiales using a nine-gene sequence dataset. Based on this analysis, the new family Penicillaginaceae is introduced and four known families are accepted: Aspergillaceae, Elaphomycetaceae, Thermoascaceae and Trichocomaceae. The Eurotiales includes 28 genera: 15 genera are accommodated in the Aspergillaceae (Aspergillago, Aspergillus, Evansstolkia, Hamigera, Leiothecium, Monascus, Penicilliopsis, Penicillium, Phialomyces, Pseudohamigera, Pseudopenicillium, Sclerocleista, Warcupiella, Xerochrysium and Xeromyces), eight in the Trichocomaceae (Acidotalaromyces, Ascospirella, Dendrosphaera, Rasamsonia, Sagenomella, Talaromyces, Thermomyces, Trichocoma), two in the Thermoascaceae (Paecilomyces, Thermoascus) and one in the Penicillaginaceae (Penicillago). The classification of the Elaphomycetaceae was not part of this study, but according to literature two genera are present in this family (Elaphomyces and Pseudotulostoma). The use of an infrageneric classification system has a long tradition in Aspergillus and Penicillium. Most recent taxonomic studies focused on the sectional level, resulting in a well-established sectional classification in these genera. In contrast, a series classification in Aspergillus and Penicillium is often outdated or lacking, but is still relevant, e.g., the allocation of a species to a series can be highly predictive in what functional characters the species might have and might be useful when using a phenotype-based identification. The majority of the series in Aspergillus and Penicillium are invalidly described and here we introduce a new series classification. Using a phylogenetic approach, often supported by phenotypic, physiologic and/or extrolite data, Aspergillus is subdivided in six subgenera, 27 sections (five new) and 75 series (73 new, one new combination), and Penicillium in two subgenera, 32 sections (seven new) and 89 series (57 new, six new combinations). Correct identification of species belonging to the Eurotiales is difficult, but crucial, as the species name is the linking pin to information. Lists of accepted species are a helpful aid for researchers to obtain a correct identification using the current taxonomic schemes. In the most recent list from 2014, 339 Aspergillus, 354 Penicillium and 88 Talaromyces species were accepted. These numbers increased significantly, and the current list includes 446 Aspergillus (32 % increase), 483 Penicillium (36 % increase) and 171 Talaromyces (94 % increase) species, showing the large diversity and high interest in these genera. We expanded this list with all genera and species belonging to the Eurotiales (except those belonging to Elaphomycetaceae). The list includes 1 187 species, distributed over 27 genera, and contains MycoBank numbers, collection numbers of type and ex-type cultures, subgenus, section and series classification data, information on the mode of reproduction, and GenBank accession numbers of ITS, beta-tubulin (BenA), calmodulin (CaM) and RNA polymerase II second largest subunit (RPB2) gene sequences.
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Key Words
- Acidotalaromyces Houbraken, Frisvad & Samson
- Acidotalaromyces lignorum (Stolk) Houbraken, Frisvad & Samson
- Ascospirella Houbraken, Frisvad & Samson
- Ascospirella lutea (Zukal) Houbraken, Frisvad & Samson
- Aspergillus chaetosartoryae Hubka, Kocsubé & Houbraken
- Classification
- Evansstolkia Houbraken, Frisvad & Samson
- Evansstolkia leycettana (H.C. Evans & Stolk) Houbraken, Frisvad & Samson
- Hamigera brevicompacta (H.Z. Kong) Houbraken, Frisvad & Samson
- Infrageneric classification
- New combinations, series
- New combinations, species
- New genera
- New names
- New sections
- New series
- New taxa
- Nomenclature
- Paecilomyces lagunculariae (C. Ram) Houbraken, Frisvad & Samson
- Penicillaginaceae Houbraken, Frisvad & Samson
- Penicillago kabunica (Baghd.) Houbraken, Frisvad & Samson
- Penicillago mirabilis (Beliakova & Milko) Houbraken, Frisvad & Samson
- Penicillago moldavica (Milko & Beliakova) Houbraken, Frisvad & Samson
- Phialomyces arenicola (Chalab.) Houbraken, Frisvad & Samson
- Phialomyces humicoloides (Bills & Heredia) Houbraken, Frisvad & Samson
- Phylogeny
- Polythetic classes
- Pseudohamigera Houbraken, Frisvad & Samson
- Pseudohamigera striata (Raper & Fennell) Houbraken, Frisvad & Samson
- Talaromyces resinae (Z.T. Qi & H.Z. Kong) Houbraken & X.C. Wang
- Talaromyces striatoconidius Houbraken, Frisvad & Samson
- Taxonomic novelties: New family
- Thermoascus verrucosus (Samson & Tansey) Houbraken, Frisvad & Samson
- Thermoascus yaguchii Houbraken, Frisvad & Samson
- in Aspergillus: sect. Bispori S.W. Peterson, Varga, Frisvad, Samson ex Houbraken
- in Aspergillus: ser. Acidohumorum Houbraken & Frisvad
- in Aspergillus: ser. Inflati (Stolk & Samson) Houbraken & Frisvad
- in Penicillium: sect. Alfrediorum Houbraken & Frisvad
- in Penicillium: ser. Adametziorum Houbraken & Frisvad
- in Penicillium: ser. Alutacea (Pitt) Houbraken & Frisvad
- sect. Crypta Houbraken & Frisvad
- sect. Eremophila Houbraken & Frisvad
- sect. Formosana Houbraken & Frisvad
- sect. Griseola Houbraken & Frisvad
- sect. Inusitata Houbraken & Frisvad
- sect. Lasseniorum Houbraken & Frisvad
- sect. Polypaecilum Houbraken & Frisvad
- sect. Raperorum S.W. Peterson, Varga, Frisvad, Samson ex Houbraken
- sect. Silvatici S.W. Peterson, Varga, Frisvad, Samson ex Houbraken
- sect. Vargarum Houbraken & Frisvad
- ser. Alliacei Houbraken & Frisvad
- ser. Ambigui Houbraken & Frisvad
- ser. Angustiporcata Houbraken & Frisvad
- ser. Arxiorum Houbraken & Frisvad
- ser. Atramentosa Houbraken & Frisvad
- ser. Aurantiobrunnei Houbraken & Frisvad
- ser. Avenacei Houbraken & Frisvad
- ser. Bertholletiarum Houbraken & Frisvad
- ser. Biplani Houbraken & Frisvad
- ser. Brevicompacta Houbraken & Frisvad
- ser. Brevipedes Houbraken & Frisvad
- ser. Brunneouniseriati Houbraken & Frisvad
- ser. Buchwaldiorum Houbraken & Frisvad
- ser. Calidousti Houbraken & Frisvad
- ser. Canini Houbraken & Frisvad
- ser. Carbonarii Houbraken & Frisvad
- ser. Cavernicolarum Houbraken & Frisvad
- ser. Cervini Houbraken & Frisvad
- ser. Chevalierorum Houbraken & Frisvad
- ser. Cinnamopurpurea Houbraken & Frisvad
- ser. Circumdati Houbraken & Frisvad
- ser. Clavigera Houbraken & Frisvad
- ser. Conjuncti Houbraken & Frisvad
- ser. Copticolarum Houbraken & Frisvad
- ser. Coremiiformes Houbraken & Frisvad
- ser. Corylophila Houbraken & Frisvad
- ser. Costaricensia Houbraken & Frisvad
- ser. Cremei Houbraken & Frisvad
- ser. Crustacea (Pitt) Houbraken & Frisvad
- ser. Dalearum Houbraken & Frisvad
- ser. Deflecti Houbraken & Frisvad
- ser. Egyptiaci Houbraken & Frisvad
- ser. Erubescentia (Pitt) Houbraken & Frisvad
- ser. Estinogena Houbraken & Frisvad
- ser. Euglauca Houbraken & Frisvad
- ser. Fennelliarum Houbraken & Frisvad
- ser. Flavi Houbraken & Frisvad
- ser. Flavipedes Houbraken & Frisvad
- ser. Fortuita Houbraken & Frisvad
- ser. Fumigati Houbraken & Frisvad
- ser. Funiculosi Houbraken & Frisvad
- ser. Gallaica Houbraken & Frisvad
- ser. Georgiensia Houbraken & Frisvad
- ser. Goetziorum Houbraken & Frisvad
- ser. Gracilenta Houbraken & Frisvad
- ser. Halophilici Houbraken & Frisvad
- ser. Herqueorum Houbraken & Frisvad
- ser. Heteromorphi Houbraken & Frisvad
- ser. Hoeksiorum Houbraken & Frisvad
- ser. Homomorphi Houbraken & Frisvad
- ser. Idahoensia Houbraken & Frisvad
- ser. Implicati Houbraken & Frisvad
- ser. Improvisa Houbraken & Frisvad
- ser. Indica Houbraken & Frisvad
- ser. Japonici Houbraken & Frisvad
- ser. Jiangxiensia Houbraken & Frisvad
- ser. Kalimarum Houbraken & Frisvad
- ser. Kiamaensia Houbraken & Frisvad
- ser. Kitamyces Houbraken & Frisvad
- ser. Lapidosa (Pitt) Houbraken & Frisvad
- ser. Leporum Houbraken & Frisvad
- ser. Leucocarpi Houbraken & Frisvad
- ser. Livida Houbraken & Frisvad
- ser. Longicatenata Houbraken & Frisvad
- ser. Macrosclerotiorum Houbraken & Frisvad
- ser. Monodiorum Houbraken & Frisvad
- ser. Multicolores Houbraken & Frisvad
- ser. Neoglabri Houbraken & Frisvad
- ser. Neonivei Houbraken & Frisvad
- ser. Nidulantes Houbraken & Frisvad
- ser. Nigri Houbraken & Frisvad
- ser. Nivei Houbraken & Frisvad
- ser. Nodula Houbraken & Frisvad
- ser. Nomiarum Houbraken & Frisvad
- ser. Noonimiarum Houbraken & Frisvad
- ser. Ochraceorosei Houbraken & Frisvad
- ser. Olivimuriarum Houbraken & Frisvad
- ser. Osmophila Houbraken & Frisvad
- ser. Paradoxa Houbraken & Frisvad
- ser. Paxillorum Houbraken & Frisvad
- ser. Penicillioides Houbraken & Frisvad
- ser. Phoenicea Houbraken & Frisvad
- ser. Pinetorum (Pitt) Houbraken & Frisvad
- ser. Polypaecilum Houbraken & Frisvad
- ser. Pulvini Houbraken & Frisvad
- ser. Quercetorum Houbraken & Frisvad
- ser. Raistrickiorum Houbraken & Frisvad
- ser. Ramigena Houbraken & Frisvad
- ser. Restricti Houbraken & Frisvad
- ser. Robsamsonia Houbraken & Frisvad
- ser. Rolfsiorum Houbraken & Frisvad
- ser. Roseopurpurea Houbraken & Frisvad
- ser. Rubri Houbraken & Frisvad
- ser. Salinarum Houbraken & Frisvad
- ser. Samsoniorum Houbraken & Frisvad
- ser. Saturniformia Houbraken & Frisvad
- ser. Scabrosa Houbraken & Frisvad
- ser. Sclerotigena Houbraken & Frisvad
- ser. Sclerotiorum Houbraken & Frisvad
- ser. Sheariorum Houbraken & Frisvad
- ser. Simplicissima Houbraken & Frisvad
- ser. Soppiorum Houbraken & Frisvad
- ser. Sparsi Houbraken & Frisvad
- ser. Spathulati Houbraken & Frisvad
- ser. Spelaei Houbraken & Frisvad
- ser. Speluncei Houbraken & Frisvad
- ser. Spinulosa Houbraken & Frisvad
- ser. Stellati Houbraken & Frisvad
- ser. Steyniorum Houbraken & Frisvad
- ser. Sublectatica Houbraken & Frisvad
- ser. Sumatraensia Houbraken & Frisvad
- ser. Tamarindosolorum Houbraken & Frisvad
- ser. Teporium Houbraken & Frisvad
- ser. Terrei Houbraken & Frisvad
- ser. Thermomutati Houbraken & Frisvad
- ser. Thiersiorum Houbraken & Frisvad
- ser. Thomiorum Houbraken & Frisvad
- ser. Unguium Houbraken & Frisvad
- ser. Unilaterales Houbraken & Frisvad
- ser. Usti Houbraken & Frisvad
- ser. Verhageniorum Houbraken & Frisvad
- ser. Versicolores Houbraken & Frisvad
- ser. Virgata Houbraken & Frisvad
- ser. Viridinutantes Houbraken & Frisvad
- ser. Vitricolarum Houbraken & Frisvad
- ser. Wentiorum Houbraken & Frisvad
- ser. Westlingiorum Houbraken & Frisvad
- ser. Whitfieldiorum Houbraken & Frisvad
- ser. Xerophili Houbraken & Frisvad
- series Tularensia (Pitt) Houbraken & Frisvad
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Affiliation(s)
- J. Houbraken
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
| | - S. Kocsubé
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - C.M. Visagie
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, P. Bag X20, Hatfield, Pretoria, 0028, South Africa
| | - N. Yilmaz
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, P. Bag X20, Hatfield, Pretoria, 0028, South Africa
| | - X.-C. Wang
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, No. 3, 1st Beichen West Road, Chaoyang District, Beijing, 100101, China
| | - M. Meijer
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
| | - B. Kraak
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
| | - V. Hubka
- Department of Botany, Charles University in Prague, Prague, Czech Republic
| | - K. Bensch
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
| | - R.A. Samson
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
| | - J.C. Frisvad
- Department of Biotechnology and Biomedicine Technical University of Denmark, Søltofts Plads, B. 221, Kongens Lyngby, DK 2800, Denmark
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23
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Schrenk D, Bignami M, Bodin L, Chipman JK, del Mazo J, Grasl‐Kraupp B, Hogstrand C, Hoogenboom L(R, Leblanc J, Nebbia CS, Nielsen E, Ntzani E, Petersen A, Sand S, Schwerdtle T, Vleminckx C, Marko D, Oswald IP, Piersma A, Routledge M, Schlatter J, Baert K, Gergelova P, Wallace H. Risk assessment of aflatoxins in food. EFSA J 2020; 18:e06040. [PMID: 32874256 PMCID: PMC7447885 DOI: 10.2903/j.efsa.2020.6040] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
EFSA was asked to deliver a scientific opinion on the risks to public health related to the presence of aflatoxins in food. The risk assessment was confined to aflatoxin B1 (AFB1), AFB2, AFG1, AFG2 and AFM1. More than 200,000 analytical results on the occurrence of aflatoxins were used in the evaluation. Grains and grain-based products made the largest contribution to the mean chronic dietary exposure to AFB1 in all age classes, while 'liquid milk' and 'fermented milk products' were the main contributors to the AFM1 mean exposure. Aflatoxins are genotoxic and AFB1 can cause hepatocellular carcinomas (HCCs) in humans. The CONTAM Panel selected a benchmark dose lower confidence limit (BMDL) for a benchmark response of 10% of 0.4 μg/kg body weight (bw) per day for the incidence of HCC in male rats following AFB1 exposure to be used in a margin of exposure (MOE) approach. The calculation of a BMDL from the human data was not appropriate; instead, the cancer potencies estimated by the Joint FAO/WHO Expert Committee on Food Additives in 2016 were used. For AFM1, a potency factor of 0.1 relative to AFB1 was used. For AFG1, AFB2 and AFG2, the in vivo data are not sufficient to derive potency factors and equal potency to AFB1 was assumed as in previous assessments. MOE values for AFB1 exposure ranged from 5,000 to 29 and for AFM1 from 100,000 to 508. The calculated MOEs are below 10,000 for AFB1 and also for AFM1 where some surveys, particularly for the younger age groups, have an MOE below 10,000. This raises a health concern. The estimated cancer risks in humans following exposure to AFB1 and AFM1 are in-line with the conclusion drawn from the MOEs. The conclusions also apply to the combined exposure to all five aflatoxins.
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24
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Pfliegler WP, Pócsi I, Győri Z, Pusztahelyi T. The Aspergilli and Their Mycotoxins: Metabolic Interactions With Plants and the Soil Biota. Front Microbiol 2020; 10:2921. [PMID: 32117074 PMCID: PMC7029702 DOI: 10.3389/fmicb.2019.02921] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 12/04/2019] [Indexed: 01/06/2023] Open
Abstract
Species of the highly diverse fungal genus Aspergillus are well-known agricultural pests, and, most importantly, producers of various mycotoxins threatening food safety worldwide. Mycotoxins are studied predominantly from the perspectives of human and livestock health. Meanwhile, their roles are far less known in nature. However, to understand the factors behind mycotoxin production, the roles of the toxins of Aspergilli must be understood from a complex ecological perspective, taking mold-plant, mold-microbe, and mold-animal interactions into account. The Aspergilli may switch between saprophytic and pathogenic lifestyles, and the production of secondary metabolites, such as mycotoxins, may vary according to these fungal ways of life. Recent studies highlighted the complex ecological network of soil microbiotas determining the niches that Aspergilli can fill in. Interactions with the soil microbiota and soil macro-organisms determine the role of secondary metabolite production to a great extent. While, upon infection of plants, metabolic communication including fungal secondary metabolites like aflatoxins, gliotoxin, patulin, cyclopiazonic acid, and ochratoxin, influences the fate of both the invader and the host. In this review, the role of mycotoxin producing Aspergillus species and their interactions in the ecosystem are discussed. We intend to highlight the complexity of the roles of the main toxic secondary metabolites as well as their fate in natural environments and agriculture, a field that still has important knowledge gaps.
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Affiliation(s)
- Walter P. Pfliegler
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - István Pócsi
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Zoltán Győri
- Institute of Nutrition, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Debrecen, Hungary
| | - Tünde Pusztahelyi
- Central Laboratory of Agricultural and Food Products, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Debrecen, Hungary
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25
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Monda E, Masanga J, Alakonya A. Variation in Occurrence and Aflatoxigenicity of Aspergillus flavus from Two Climatically Varied Regions in Kenya. Toxins (Basel) 2020; 12:toxins12010034. [PMID: 31935922 PMCID: PMC7020432 DOI: 10.3390/toxins12010034] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 12/11/2019] [Accepted: 12/26/2019] [Indexed: 02/01/2023] Open
Abstract
Aflatoxins are carcinogenic chemical metabolites produced by Aspergillus spp. of the section Flavi. In Kenya, Aspergillus flavus is the most prevalent and has been associated with several acute and chronic aflatoxin outbreaks in the past. In this study, we evaluated the occurrence of A. flavus in soils from two agro-ecological regions with contrasting climatic conditions, aflatoxin contamination histories and cropping systems. Aspergillus spp. were first isolated from soils before the identification and determination of their aflatoxigenicity. Further, we determined the occurrence of Pseudomonas and Bacillus spp. in soils from the two regions. These bacterial species have long been associated with biological control of several plant pathogens including Aspergillus spp. Our results show that A. flavus occurred widely and produced comparatively higher total aflatoxin levels in all (100%) study sites from the eastern to the western regions of Kenya. For the western region, A. flavus was detected in 4 locations (66.7%) that were previously under maize cultivation with the isolates showing low aflatoxigenicity. A. flavus was not isolated from soils under sugarcane cultivation. Distribution of the two bacterial species varied across the regions but we detected a weak relationship between occurrence of bacterial species and A. flavus. We discuss these findings in the context of the influence of climate, microbial profiles, cropping systems and applicability in the deployment of biological control remedies against aflatoxin contamination.
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Affiliation(s)
- Ethel Monda
- Department of Biochemistry, Biotechnology and Microbiology, Kenyatta University, Thika Road, Nairobi P.O. Box 43844-00100, Kenya; (E.M.); (J.M.)
| | - Joel Masanga
- Department of Biochemistry, Biotechnology and Microbiology, Kenyatta University, Thika Road, Nairobi P.O. Box 43844-00100, Kenya; (E.M.); (J.M.)
| | - Amos Alakonya
- Seed Health Unit, Genetic Resources Program, International Maize and Wheat Improvement Center (CIMMYT), Carretera Mexico-Veracruz Km. 45 El Batan, Texcoco, Mexico C.P. 56237, Mexico
- Correspondence:
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26
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Makhlouf J, Carvajal-Campos A, Querin A, Tadrist S, Puel O, Lorber S, Oswald IP, Hamze M, Bailly JD, Bailly S. Morphologic, molecular and metabolic characterization of Aspergillus section Flavi in spices marketed in Lebanon. Sci Rep 2019; 9:5263. [PMID: 30918318 PMCID: PMC6437153 DOI: 10.1038/s41598-019-41704-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 03/14/2019] [Indexed: 01/01/2023] Open
Abstract
Spices are used extensively in Lebanon not only to flavour foods but also for their medicinal properties. To date, no data are available regarding the nature of the toxigenic fungal species that may contaminate these products at the marketing stage in this country. Eighty samples corresponding to 14 different types of spices were collected throughout Lebanon to characterize the Aspergillus section Flavi contaminating spices marketed in Lebanon and the toxigenic potential of these fungal species. Most fungal genera and species were identified as belonging to Aspergillus section Flavi. Aspergillus flavus was the most frequent species, representing almost 80% of the isolates. Although identified as A. flavus by molecular analysis, some strains displayed atypical morphological features. Seven strains of A. tamarii and one A. minisclerotigenes were also isolated. Analyses of toxigenic potential demonstrated that almost 80% of strains were able to produce mycotoxins, 47% produced aflatoxins, and 72% produced cyclopiazonic acid, alone or in combination with aflatoxins.
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Affiliation(s)
- Joya Makhlouf
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 180 Chemin de Tournefeuille, F-31027, Toulouse, France.,Health and Environment Microbiology Laboratory, Lebanese University, Beirut, Lebanon
| | - Amaranta Carvajal-Campos
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 180 Chemin de Tournefeuille, F-31027, Toulouse, France
| | - Arlette Querin
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 180 Chemin de Tournefeuille, F-31027, Toulouse, France
| | - Soraya Tadrist
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 180 Chemin de Tournefeuille, F-31027, Toulouse, France
| | - Olivier Puel
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 180 Chemin de Tournefeuille, F-31027, Toulouse, France
| | - Sophie Lorber
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 180 Chemin de Tournefeuille, F-31027, Toulouse, France
| | - Isabelle P Oswald
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 180 Chemin de Tournefeuille, F-31027, Toulouse, France
| | - Monzer Hamze
- Health and Environment Microbiology Laboratory, Lebanese University, Beirut, Lebanon
| | - Jean-Denis Bailly
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 180 Chemin de Tournefeuille, F-31027, Toulouse, France.
| | - Sylviane Bailly
- Toxalim (Research Center in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 180 Chemin de Tournefeuille, F-31027, Toulouse, France
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