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Nguyen TBH, Foulongne-Oriol M, Jany JL, le Floch G, Picot A. New insights into mycotoxin risk management through fungal population genetics and genomics. Crit Rev Microbiol 2024:1-22. [PMID: 39188135 DOI: 10.1080/1040841x.2024.2392179] [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: 02/09/2024] [Revised: 05/08/2024] [Accepted: 08/09/2024] [Indexed: 08/28/2024]
Abstract
Mycotoxin contamination of food and feed is a major global concern. Chronic or acute dietary exposure to contaminated food and feed can negatively affect both human and animal health. Contamination occurs through plant infection by toxigenic fungi, primarily Aspergillus and Fusarium spp., either before or after harvest. Despite the application of various management strategies, controlling these pathogens remains a major challenge primarily because of their ability to adapt to environmental changes and selection pressures. Understanding the genetic structure of plant pathogen populations is pivotal for gaining new insights into their biology and epidemiology, as well as for understanding the mechanisms behind their adaptability. Such deeper understanding is crucial for developing effective and preemptive management strategies tailored to the evolving nature of pathogenic populations. This review focuses on the population-level variations within the two most economically significant toxigenic fungal genera according to space, host, and pathogenicity. Outcomes in terms of migration patterns, gene flow within populations, mating abilities, and the potential for host jumps are examined. We also discuss effective yet often underutilized applications of population genetics and genomics to address practical challenges in the epidemiology and disease control of toxigenic fungi.
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Affiliation(s)
- Toan Bao Hung Nguyen
- Univ Brest, INRAE, Laboratoire Universitaire de Biodiversité et Écologie Microbienne, Plouzané, France
| | | | - Jean-Luc Jany
- Univ Brest, INRAE, Laboratoire Universitaire de Biodiversité et Écologie Microbienne, Plouzané, France
| | - Gaétan le Floch
- Univ Brest, INRAE, Laboratoire Universitaire de Biodiversité et Écologie Microbienne, Plouzané, France
| | - Adeline Picot
- Univ Brest, INRAE, Laboratoire Universitaire de Biodiversité et Écologie Microbienne, Plouzané, France
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2
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Sweany RR, Mack BM, Gebru ST, Mammel MK, Cary JW, Moore GG, Lebar MD, Carter-Wientjes CH, Gilbert MK. Divergent Aspergillus flavus corn population is composed of prolific conidium producers: Implications for saprophytic disease cycle. Mycologia 2024; 116:536-557. [PMID: 38727560 DOI: 10.1080/00275514.2024.2343645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 04/12/2024] [Indexed: 06/29/2024]
Abstract
The ascomycete fungus Aspergillus flavus infects and contaminates corn, peanuts, cottonseed, and tree nuts with toxic and carcinogenic aflatoxins. Subdivision between soil and host plant populations suggests that certain A. flavus strains are specialized to infect peanut, cotton, and corn despite having a broad host range. In this study, the ability of strains isolated from corn and/or soil in 11 Louisiana fields to produce conidia (field inoculum and male gamete) and sclerotia (resting bodies and female gamete) was assessed and compared with genotypic single-nucleotide polymorphism (SNP) differences between whole genomes. Corn strains produced upward of 47× more conidia than strains restricted to soil. Conversely, corn strains produced as much as 3000× fewer sclerotia than soil strains. Aspergillus flavus strains, typified by sclerotium diameter (small S-strains, <400 μm; large L-strains, >400 μm), belonged to separate clades. Several strains produced a mixture (M) of S and L sclerotia, and an intermediate number of conidia and sclerotia, compared with typical S-strains (minimal conidia, copious sclerotia) and L-strains (copious conidia, minimal sclerotia). They also belonged to a unique phylogenetic mixed (M) clade. Migration from soil to corn positively correlated with conidium production and negatively correlated with sclerotium production. Genetic differences correlated with differences in conidium and sclerotium production. Opposite skews in female (sclerotia) or male (conidia) gametic production by soil or corn strains, respectively, resulted in reduced effective breeding population sizes when comparing male:female gamete ratio with mating type distribution. Combining both soil and corn populations increased the effective breeding population, presumably due to contribution of male gametes from corn, which fertilize sclerotia on the soil surface. Incongruencies between aflatoxin clusters, strain morphotype designation, and whole genome phylogenies suggest a history of sexual reproduction within this Louisiana population, demonstrating the importance of conidium production, as infectious propagules and as fertilizers of the A. flavus soil population.
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Affiliation(s)
- Rebecca R Sweany
- Food and Feed Safety Research Unit, Southern Regional Research Center, U.S. Department of Agriculture, New Orleans, Louisiana, 70124
| | - Brian M Mack
- Food and Feed Safety Research Unit, Southern Regional Research Center, U.S. Department of Agriculture, New Orleans, Louisiana, 70124
| | - Solomon T Gebru
- Division of Virulence Assessment, Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, Maryland, 20708
| | - Mark K Mammel
- Division of Molecular Biology, Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, Maryland, 20708
| | - Jeffrey W Cary
- Food and Feed Safety Research Unit, Southern Regional Research Center, U.S. Department of Agriculture, New Orleans, Louisiana, 70124
| | - Geromy G Moore
- Food and Feed Safety Research Unit, Southern Regional Research Center, U.S. Department of Agriculture, New Orleans, Louisiana, 70124
| | - Matthew D Lebar
- Food and Feed Safety Research Unit, Southern Regional Research Center, U.S. Department of Agriculture, New Orleans, Louisiana, 70124
| | - Carol H Carter-Wientjes
- Food and Feed Safety Research Unit, Southern Regional Research Center, U.S. Department of Agriculture, New Orleans, Louisiana, 70124
| | - Matthew K Gilbert
- Food and Feed Safety Research Unit, Southern Regional Research Center, U.S. Department of Agriculture, New Orleans, Louisiana, 70124
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3
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Moore GG, Mack BM, Wendt KL, Castano-Duque L, Anderson VM, Cichewicz RH. Genomic and metabolomic diversity within a familial population of Aspergillus flavus. Mol Microbiol 2024; 121:927-939. [PMID: 38396382 DOI: 10.1111/mmi.15244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/12/2024] [Accepted: 02/11/2024] [Indexed: 02/25/2024]
Abstract
Aspergillus flavus is an agriculturally significant micro-fungus having potential to contaminate food and feed crops with toxic secondary metabolites such as aflatoxin (AF) and cyclopiazonic acid (CPA). Research has shown A. flavus strains can overcome heterokaryon incompatibility and undergo meiotic recombination as teleomorphs. Although evidence of recombination in the AF gene cluster has been reported, the impacts of recombination on genotype and metabolomic phenotype in a single generation are lacking. In previous studies, we paired an aflatoxigenic MAT1-1 A. flavus strain with a non-aflatoxigenic MAT1-2 A. flavus strain that had been tagged with green fluorescent protein and then 10 F1 progenies (a mix of fluorescent and non-fluorescent) were randomly selected from single-ascospore colonies and broadly examined for evidence of recombination. In this study, we determined four of those 10 F1 progenies were recombinants because they were not vegetatively compatible with either parent or their siblings, and they exhibited other distinctive traits that could only result from meiotic recombination. The other six progenies examined shared genomic identity with the non-aflatoxigenic, fluorescent, and MAT1-2 parent, but were metabolically distinct. This study highlights phenotypic and genomic changes that may occur in a single generation from the outcrossing of sexually compatible strains of A. flavus.
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Affiliation(s)
- Geromy G Moore
- Southern Regional Research Center, USDA-ARS, New Orleans, Louisiana, USA
| | - Brian M Mack
- Southern Regional Research Center, USDA-ARS, New Orleans, Louisiana, USA
| | - Karen L Wendt
- Department of Chemistry and Biochemistry, Natural Products Discovery Group, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Lina Castano-Duque
- Southern Regional Research Center, USDA-ARS, New Orleans, Louisiana, USA
| | - Victoria M Anderson
- Department of Chemistry and Biochemistry, Natural Products Discovery Group, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Robert H Cichewicz
- Department of Chemistry and Biochemistry, Natural Products Discovery Group, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
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4
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Gangurde SS, Korani W, Bajaj P, Wang H, Fountain JC, Agarwal G, Pandey MK, Abbas HK, Chang PK, Holbrook CC, Kemerait RC, Varshney RK, Dutta B, Clevenger JP, Guo B. Aspergillus flavus pangenome (AflaPan) uncovers novel aflatoxin and secondary metabolite associated gene clusters. BMC PLANT BIOLOGY 2024; 24:354. [PMID: 38693487 PMCID: PMC11061970 DOI: 10.1186/s12870-024-04950-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 03/26/2024] [Indexed: 05/03/2024]
Abstract
BACKGROUND Aspergillus flavus is an important agricultural and food safety threat due to its production of carcinogenic aflatoxins. It has high level of genetic diversity that is adapted to various environments. Recently, we reported two reference genomes of A. flavus isolates, AF13 (MAT1-2 and highly aflatoxigenic isolate) and NRRL3357 (MAT1-1 and moderate aflatoxin producer). Where, an insertion of 310 kb in AF13 included an aflatoxin producing gene bZIP transcription factor, named atfC. Observations of significant genomic variants between these isolates of contrasting phenotypes prompted an investigation into variation among other agricultural isolates of A. flavus with the goal of discovering novel genes potentially associated with aflatoxin production regulation. Present study was designed with three main objectives: (1) collection of large number of A. flavus isolates from diverse sources including maize plants and field soils; (2) whole genome sequencing of collected isolates and development of a pangenome; and (3) pangenome-wide association study (Pan-GWAS) to identify novel secondary metabolite cluster genes. RESULTS Pangenome analysis of 346 A. flavus isolates identified a total of 17,855 unique orthologous gene clusters, with mere 41% (7,315) core genes and 59% (10,540) accessory genes indicating accumulation of high genomic diversity during domestication. 5,994 orthologous gene clusters in accessory genome not annotated in either the A. flavus AF13 or NRRL3357 reference genomes. Pan-genome wide association analysis of the genomic variations identified 391 significant associated pan-genes associated with aflatoxin production. Interestingly, most of the significantly associated pan-genes (94%; 369 associations) belonged to accessory genome indicating that genome expansion has resulted in the incorporation of new genes associated with aflatoxin and other secondary metabolites. CONCLUSION In summary, this study provides complete pangenome framework for the species of Aspergillus flavus along with associated genes for pathogen survival and aflatoxin production. The large accessory genome indicated large genome diversity in the species A. flavus, however AflaPan is a closed pangenome represents optimum diversity of species A. flavus. Most importantly, the newly identified aflatoxin producing gene clusters will be a new source for seeking aflatoxin mitigation strategies and needs new attention in research.
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Affiliation(s)
- Sunil S Gangurde
- Department of Plant Pathology, University of Georgia, Tifton, GA, 31793, USA
- Crop Protection and Management Research Unit, USDA-ARS, Tifton, GA, 31793, USA
| | - Walid Korani
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, 35806, USA
| | - Prasad Bajaj
- International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, 502324, Telangana, India
| | - Hui Wang
- Department of Plant Pathology, University of Georgia, Tifton, GA, 31793, USA
| | - Jake C Fountain
- Department of Plant Pathology, University of Georgia, Griffin, GA, 30223, USA
| | - Gaurav Agarwal
- Department of Plant Biology, Michigan State University, East Lansing, MI, 48823, USA
| | - Manish K Pandey
- International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, 502324, Telangana, India.
| | - Hamed K Abbas
- Biological Control of Pests Research Unit, USDA-ARS, Stoneville, MS, 38776, USA
| | - Perng-Kuang Chang
- Southern Regional Research Center, USDA-ARS, New Orleans, LA, 70124, USA
| | - C Corley Holbrook
- Crop Protection and Management Research Unit, USDA-ARS, Tifton, GA, 31793, USA
| | - Robert C Kemerait
- Department of Plant Pathology, University of Georgia, Tifton, GA, 31793, USA
| | - Rajeev K Varshney
- WA State Biotechnology Centre, Centre for Crop and Food innovation, Food Futures Institute, Murdoch University, Murdoch, WA, 6150, Australia
| | - Bhabesh Dutta
- Department of Plant Pathology, University of Georgia, Tifton, GA, 31793, USA
| | - Josh P Clevenger
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, 35806, USA.
| | - Baozhu Guo
- Crop Protection and Management Research Unit, USDA-ARS, Tifton, GA, 31793, USA.
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5
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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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6
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Oduro-Mensah D, Lowor ST, Bukari Y, Donkor JK, Minnah B, Nuhu AH, Dontoh D, Amadu AA, Ocloo A. Cocoa-associated filamentous fungi for the biocontrol of aflatoxigenic Aspergillus flavus. J Basic Microbiol 2023; 63:1279-1292. [PMID: 37485741 DOI: 10.1002/jobm.202300163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/30/2023] [Accepted: 07/01/2023] [Indexed: 07/25/2023]
Abstract
Aflatoxin and other mycotoxin contamination are major threats to global food security and present an urgent need to secure the global food crop against spoilage by mycotoxigenic fungi. Cocoa material is noted for naturally low aflatoxin contamination. This study was designed to assess the potential for harnessing cocoa-associated filamentous fungi for the biocontrol of aflatoxigenic Aspergillus flavus. The candidate fungi were isolated from fermented cocoa beans collected from four cocoa-growing areas in Ghana. Molecular characterization included Internal Transcribed Spacer (ITS)-sequencing for identification and polymer chain reaction (PCR) to determine mating type. Effects of the candidate isolates on growth and aflatoxin-production by an aflatoxigenic A. flavus isolate (BANGA1) were assessed. Aflatoxin production was monitored by UV fluorescence and quantified by enzyme-linked immunosorbent assay (ELISA). Thirty-six filamentous fungi were cultured and identified as Aspergillus, Cladosporium, Lichtheimia, or Trichoderma spp. isolates. The isolates generally interacted negatively with BANGA1 growth and aflatoxin production. The Aspergillus niger and Aspergillus aculeatus biocontrol candidates showed the strongest colony antagonism (54%-94%) and reduction in aflatoxin production (12%-50%) on agar. In broth, the A. niger isolates reduced aflatoxin production by up to 97%. Metabolites from the A. niger isolates showed the strongest inhibition of growth by BANGA1 and inhibited aflatoxin production. Four of the candidate isolates belonged to the MAT1-1 mating type and 12 identified as MAT1-2. This may be indicative of the potential for genetic recombination events between fungi in the field, a finding which is particularly relevant to the risk posed by A. flavus biocontrol measures that rely on atoxigenic A. flavus strains.
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Affiliation(s)
- Daniel Oduro-Mensah
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
- African Centre of Excellence for Mycotoxin and Food Safety, Federal University of Technology, Minna, Niger State, Nigeria
| | - Sammy T Lowor
- Physiology/Biochemistry Division, Cocoa Research Institute of Ghana, New Tafo-Akim, Ghana
| | - Yahaya Bukari
- Plant Pathology Division, Cocoa Research Institute of Ghana, New Tafo-Akim, Ghana
| | - Jacob Kwaku Donkor
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Bismark Minnah
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Abdul Hamid Nuhu
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
- Mycotoxins and Histamines Laboratory, Ghana Standards Authority, Accra, Ghana
| | - Derry Dontoh
- Mycotoxins and Histamines Laboratory, Ghana Standards Authority, Accra, Ghana
| | - Ayesha Algade Amadu
- Council for Scientific and Industrial Research-Water Research Institute, Ghana
- Environmental Biology and Health Division, Nanjing University of Science and Technology, Nanjing, Jiangsu Province, China
| | - Augustine Ocloo
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
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7
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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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8
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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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9
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Molo MS, White JB, Cornish V, Gell RM, Baars O, Singh R, Carbone MA, Isakeit T, Wise KA, Woloshuk CP, Bluhm BH, Horn BW, Heiniger RW, Carbone I. Asymmetrical lineage introgression and recombination in populations of Aspergillus flavus: Implications for biological control. PLoS One 2022; 17:e0276556. [PMID: 36301851 PMCID: PMC9620740 DOI: 10.1371/journal.pone.0276556] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 10/08/2022] [Indexed: 11/23/2022] Open
Abstract
Aspergillus flavus is an agriculturally important fungus that causes ear rot of maize and produces aflatoxins, of which B1 is the most carcinogenic naturally-produced compound. In the US, the management of aflatoxins includes the deployment of biological control agents that comprise two nonaflatoxigenic A. flavus strains, either Afla-Guard (member of lineage IB) or AF36 (lineage IC). We used genotyping-by-sequencing to examine the influence of both biocontrol agents on native populations of A. flavus in cornfields in Texas, North Carolina, Arkansas, and Indiana. This study examined up to 27,529 single-nucleotide polymorphisms (SNPs) in a total of 815 A. flavus isolates, and 353 genome-wide haplotypes sampled before biocontrol application, three months after biocontrol application, and up to three years after initial application. Here, we report that the two distinct A. flavus evolutionary lineages IB and IC differ significantly in their frequency distributions across states. We provide evidence of increased unidirectional gene flow from lineage IB into IC, inferred to be due to the applied Afla-Guard biocontrol strain. Genetic exchange and recombination of biocontrol strains with native strains was detected in as little as three months after biocontrol application and up to one and three years later. There was limited inter-lineage migration in the untreated fields. These findings suggest that biocontrol products that include strains from lineage IB offer the greatest potential for sustained reductions in aflatoxin levels over several years. This knowledge has important implications for developing new biocontrol strategies.
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Affiliation(s)
- Megan S. Molo
- Department of Entomology and Plant Pathology, Center for Integrated
Fungal Research, North Carolina State University, Raleigh, NC, United States of
America
| | - James B. White
- Department of Entomology and Plant Pathology, Center for Integrated
Fungal Research, North Carolina State University, Raleigh, NC, United States of
America
| | - Vicki Cornish
- Department of Entomology and Plant Pathology, Center for Integrated
Fungal Research, North Carolina State University, Raleigh, NC, United States of
America
| | - Richard M. Gell
- Department of Entomology and Plant Pathology, Center for Integrated
Fungal Research, North Carolina State University, Raleigh, NC, United States of
America
- Program of Genetics, North Carolina State University, Raleigh, North
Carolina, United States of America
| | - Oliver Baars
- Department of Entomology and Plant Pathology, Center for Integrated
Fungal Research, North Carolina State University, Raleigh, NC, United States of
America
| | - Rakhi Singh
- Department of Entomology and Plant Pathology, Center for Integrated
Fungal Research, North Carolina State University, Raleigh, NC, United States of
America
| | - Mary Anna Carbone
- Center for Integrated Fungal Research and Department of Plant and
Microbial Biology, North Carolina State University, Raleigh, NC, United States
of America
| | - Thomas Isakeit
- Department of Plant Pathology and Microbiology, Texas AgriLife Extension
Service, Texas A&M University, College Station, TX, United States of
America
| | - Kiersten A. Wise
- Department of Plant Pathology, University of Kentucky, Princeton, KY,
United States of America
| | - Charles P. Woloshuk
- Department of Plant Pathology and Botany, Purdue University, West
Lafayette, IN, United States of America
| | - Burton H. Bluhm
- University of Arkansas Division of Agriculture, Department of Entomology
and Plant Pathology, Fayetteville, AR, United States of
America
| | - Bruce W. Horn
- United States Department of Agriculture, Agriculture Research Service,
Dawson, GA, United States of America
| | - Ron W. Heiniger
- Department of Crop and Soil Sciences, North Carolina State University,
Raleigh, NC, United States of America
| | - Ignazio Carbone
- Department of Entomology and Plant Pathology, Center for Integrated
Fungal Research, North Carolina State University, Raleigh, NC, United States of
America
- Program of Genetics, North Carolina State University, Raleigh, North
Carolina, United States of America
- * E-mail:
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10
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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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11
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Cai Y, Nie Y, Gao Y, Huang B. Natural populations of the entomopathogenic fungus Beauveria bassiana in Chinese forest ecosystems are diverse and reveal equal frequencies of mating types within phylogenetic species. FUNGAL ECOL 2022. [DOI: 10.1016/j.funeco.2021.101139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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12
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Aspergillus flavus La3279, a component strain of the Aflasafe™ biocontrol product, contains a partial aflatoxin biosynthesis gene cluster followed by a genomic region highly variable among A. flavus isolates. Int J Food Microbiol 2022; 366:109559. [DOI: 10.1016/j.ijfoodmicro.2022.109559] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/31/2022] [Indexed: 11/18/2022]
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13
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Genome sequencing of the neotype strain CBS 554.65 reveals the MAT1-2 locus of Aspergillus niger. BMC Genomics 2021; 22:679. [PMID: 34548025 PMCID: PMC8454179 DOI: 10.1186/s12864-021-07990-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 09/03/2021] [Indexed: 12/05/2022] Open
Abstract
Background Aspergillus niger is a ubiquitous filamentous fungus widely employed as a cell factory thanks to its abilities to produce a wide range of organic acids and enzymes. Its genome was one of the first Aspergillus genomes to be sequenced in 2007, due to its economic importance and its role as model organism to study fungal fermentation. Nowadays, the genome sequences of more than 20 A. niger strains are available. These, however, do not include the neotype strain CBS 554.65. Results The genome of CBS 554.65 was sequenced with PacBio. A high-quality nuclear genome sequence consisting of 17 contigs with a N50 value of 4.07 Mbp was obtained. The assembly covered all the 8 centromeric regions of the chromosomes. In addition, a complete circular mitochondrial DNA assembly was obtained. Bioinformatic analyses revealed the presence of a MAT1-2-1 gene in this genome, contrary to the most commonly used A. niger strains, such as ATCC 1015 and CBS 513.88, which contain a MAT1-1-1 gene. A nucleotide alignment showed a different orientation of the MAT1–1 locus of ATCC 1015 compared to the MAT1–2 locus of CBS 554.65, relative to conserved genes flanking the MAT locus. Within 24 newly sequenced isolates of A. niger half of them had a MAT1–1 locus and the other half a MAT1–2 locus. The genomic organization of the MAT1–2 locus in CBS 554.65 is similar to other Aspergillus species. In contrast, the region comprising the MAT1–1 locus is flipped in all sequenced strains of A. niger. Conclusions This study, besides providing a high-quality genome sequence of an important A. niger strain, suggests the occurrence of genetic flipping or switching events at the MAT1–1 locus of A. niger. These results provide new insights in the mating system of A. niger and could contribute to the investigation and potential discovery of sexuality in this species long thought to be asexual. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07990-8.
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14
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Bock CH, Young CA, Zhang M, Chen C, Brannen PM, Adaskaveg J, Charlton ND. Mating Type Idiomorphs, Heterothallism, and High Genetic Diversity in Venturia carpophila, Cause of Peach Scab. PHYTOPATHOLOGY 2021; 111:408-424. [PMID: 32748736 DOI: 10.1094/phyto-12-19-0485-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Scab (caused by Venturia carpophila) is a major disease affecting peach in the eastern United States. The aims of the study were to characterize the mating-type loci in V. carpophila, determine whether they are in equilibrium, and assess the population genetic diversity and structure of the pathogen. The mating-type gene MAT1-1-1 was identified in isolate JP3-5 in an available genome sequence, and the MAT1-2-1 gene was PCR amplified from isolate PS1-1, thus indicating a heterothallic structure. Mating-type loci structures were consistent with those of other Venturia spp. (V. effusa and V. inaequalis): the mating-type gene is positioned between APN2 encoding a DNA lyase and a gene encoding a Pleckstrin homology domain. Primers designed to each of the mating-type genes and a reference gene TUB2 were used as a multiplex PCR to screen a population (n = 81) of V. carpophila from various locations in the eastern United States. Mating types in five of the nine populations studied were in equilibrium. Among the 81 isolates, there were 69 multilocus genotypes. A population genetic analysis of the populations with >10 individuals (four populations) showed them to be genetically diverse. Linkage disequilibrium was found in five of nine populations with ≥4 isolates. A discriminant analysis of principal components indicated three genetic clusters, although extensive admixture was observed. Mating-type identification in V. carpophila provides a basis for understanding reproductive methods of the pathogen and can be a basis for further studies of the genetics of the peach scab pathogen.
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Affiliation(s)
- Clive H Bock
- United States Department of Agriculture-Agricultural Research Service-Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008
| | - Carolyn A Young
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401
| | - Minling Zhang
- United States Department of Agriculture-Agricultural Research Service-Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008
| | - Chunxian Chen
- United States Department of Agriculture-Agricultural Research Service-Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008
| | - Phillip M Brannen
- Department of Plant Pathology, University of Georgia, 2105 Miller Plant Sciences Building, Athens, GA 30602
| | - Jim Adaskaveg
- Department of Plant Pathology and Microbiology, University of California Riverside, Riverside, CA 92521
| | - Nikki D Charlton
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401
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15
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Moore GG. Practical considerations will ensure the continued success of pre-harvest biocontrol using non-aflatoxigenic Aspergillus flavus strains. Crit Rev Food Sci Nutr 2021; 62:4208-4225. [PMID: 33506687 DOI: 10.1080/10408398.2021.1873731] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
There is an important reason for the accelerated use of non-aflatoxigenic Aspergillus flavus to mitigate pre-harvest aflatoxin contamination… it effectively addresses the imperative need for safer food and feed. Now that we have decades of proof of the effectiveness of A. flavus as biocontrol, it is time to improve several aspects of this strategy. If we are to continue relying heavily on this form of aflatoxin mitigation, there are considerations we must acknowledge, and actions we must take, to ensure that we are best wielding this strategy to our advantage. These include its: (1) potential to produce other mycotoxins, (2) persistence in the field in light of several ecological factors, (3) its reproductive and genetic stability, (4) the mechanism(s) employed that allow it to elicit control over aflatoxigenic strains and species of agricultural importance and (5) supplemental alternatives that increase its effectiveness. There is a need to be consistent, practical and thoughtful when it comes to implementing this method of mycotoxin mitigation since these fungi are living organisms that have been adapting, evolving and surviving on this planet for tens-of-millions of years. This document will serve as a critical review of the literature regarding pre-harvest A. flavus biocontrol and will discuss opportunities for improvements.
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Affiliation(s)
- Geromy G Moore
- United States Department of Agriculture, Agricultural Research Service, New Orleans, USA
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16
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Jun SC, Kim JH, Han KH. The Conserved MAP Kinase MpkB Regulates Development and Sporulation without Affecting Aflatoxin Biosynthesis in Aspergillus flavus. J Fungi (Basel) 2020; 6:jof6040289. [PMID: 33207581 PMCID: PMC7711526 DOI: 10.3390/jof6040289] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 12/20/2022] Open
Abstract
In eukaryotes, the MAP kinase signaling pathway plays pivotal roles in regulating the expression of genes required for growth, development, and stress response. Here, we deleted the mpkB gene (AFLA_034170), an ortholog of the Saccharomyces cerevisiae FUS3 gene, to characterize its function in Aspergillus flavus, a cosmopolitan, pathogenic, and aflatoxin-producing fungus. Previous studies revealed that MpkB positively regulates sexual and asexual differentiation in Aspergillus nidulans. In A. flavus, mpkB deletion resulted in an approximately 60% reduction in conidia production compared to the wild type without mycelial growth defects. Moreover, the mutant produced immature and abnormal conidiophores exhibiting vesicular dome-immaturity in the conidiophore head, decreased phialide numbers, and very short stalks. Interestingly, the ΔmpkB mutant could not produce sclerotia but produced aflatoxin B1 normally. Taken together, these results suggest that the A. flavus MpkB MAP kinase positively regulates conidiation and sclerotia formation but is not involved in the production of secondary metabolites such as aflatoxin B1.
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Affiliation(s)
| | - Jong-Hwa Kim
- Correspondence: (J.-H.K.); (K.-H.H.); Tel.: +82-63-290-1439 (J.-H.K.); +82-63-290-1427 (K.-H.H.)
| | - Kap-Hoon Han
- Correspondence: (J.-H.K.); (K.-H.H.); Tel.: +82-63-290-1439 (J.-H.K.); +82-63-290-1427 (K.-H.H.)
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17
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Gell RM, Horn BW, Carbone I. Genetic map and heritability of Aspergillus flavus. Fungal Genet Biol 2020; 144:103478. [PMID: 33059038 DOI: 10.1016/j.fgb.2020.103478] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 07/31/2020] [Accepted: 10/07/2020] [Indexed: 12/30/2022]
Abstract
The carcinogenic aflatoxins are a human health concern as well as an economic burden to corn, peanut and other crops grown within the United States and globally. Aflatoxins are produced by fungi species in Aspergillus section Flavi, primarily Aspergillus flavus. Though previously thought of as only asexual, A. flavus has recently been found to undergo sexual reproduction both in laboratory crosses and in the field. To elucidate the consequences of genetic exchange through a single generation of the sexual cycle within A. flavus, we constructed genetic maps based on three mapping populations, each composed of the parental strains and approximately 70 F1 progeny. Genome-wide data using double digest Restriction Associated DNA sequencing identified 496, 811, and 576 significant polymorphisms differentiating parents across eight linkage groups; these polymorphisms served as markers. Average spacing between marker loci was 3.1, 2.1, and 3.5 map units and overall map length was 1504.4, 1669.2, and 2001.3 cM. Recombination was non-randomly distributed across chromosomes with an average rate of recombination of about 46.81 cM per Mbp. We showed inheritance of mitochondrial loci from the sclerotial (female) parent in crosses, whereas nuclear loci showed a 1:1 segregation ratio from both parents. The linkage map will be useful in QTL analyses to identify traits that increase sexual fertility in A. flavus and modulate aflatoxin production, both of which have significant implications for sustainable reduction of aflatoxin contamination using biological control agents.
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Affiliation(s)
- Richard M Gell
- Center for Integrated Fungal Research, Program of Genetics, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, USA
| | - Bruce W Horn
- National Peanut Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Dawson, GA, USA
| | - Ignazio Carbone
- Center for Integrated Fungal Research, Program of Genetics, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, USA.
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18
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Luis JM, Carbone I, Payne GA, Bhatnagar D, Cary JW, Moore GG, Lebar MD, Wei Q, Mack B, Ojiambo PS. Characterization of morphological changes within stromata during sexual reproduction in Aspergillus flavus. Mycologia 2020; 112:908-920. [PMID: 32821029 DOI: 10.1080/00275514.2020.1800361] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Aspergillus flavus contaminates agricultural products worldwide with carcinogenic aflatoxins that pose a serious health risk to humans and animals. The fungus survives adverse environmental conditions through production of sclerotia. When fertilized by a compatible conidium of an opposite mating type, a sclerotium transforms into a stroma within which ascocarps, asci, and ascospores are formed. However, the transition from a sclerotium to a stroma during sexual reproduction in A. flavus is not well understood. Early events during the interaction between sexually compatible strains of A. flavus were visualized using conidia of a green fluorescent protein (GFP)-labeled MAT1-1 strain and sclerotia of an mCherry-labeled MAT1-2 strain. Both conidia and sclerotia of transformed strains germinated to produce hyphae within 24 h of incubation. Hyphal growth of these two strains produced what appeared to be a network of interlocking hyphal strands that were observed at the base of the mCherry-labeled sclerotia (i.e., region in contact with agar surface) after 72 h of incubation. At 5 wk following incubation, intracellular green-fluorescent hyphal strands were observed within the stromatal matrix of the mCherry-labeled strain. Scanning electron microscopy of stromata from a high- and low-fertility cross and unmated sclerotia was used to visualize the formation and development of sexual structures within the stromatal and sclerotial matrices, starting at the time of crossing and thereafter every 2 wk until 8 wk of incubation. Morphological differences between sclerotia and stromata became apparent at 4 wk of incubation. Internal hyphae and croziers were detected inside multiple ascocarps that developed within the stromatal matrix of the high-fertility cross but were not detected in the matrix of the low-fertility cross or the unmated sclerotia. At 6 to 8 wk of incubation, hyphal tips produced numerous asci, each containing one to eight ascospores that emerged out of an ascus following the breakdown of the ascus wall. These observations broaden our knowledge of early events during sexual reproduction and suggest that hyphae from the conidium-producing strain may be involved in the early stages of sexual reproduction in A. flavus. When combined with omics data, these findings could be useful in further exploration of the molecular and biochemical mechanisms underlying sexual reproduction in A. flavus.
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Affiliation(s)
- Jane Marian Luis
- Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University , Raleigh, NC 27695
| | - Ignazio Carbone
- Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University , Raleigh, NC 27695
| | - Gary A Payne
- Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University , Raleigh, NC 27695
| | - Deepak Bhatnagar
- Southern Regional Research Center, Agricultural Research Service , United States Department of Agriculture, New Orleans, Louisiana 70124
| | - Jeffrey W Cary
- Southern Regional Research Center, Agricultural Research Service , United States Department of Agriculture, New Orleans, Louisiana 70124
| | - Geromy G Moore
- Southern Regional Research Center, Agricultural Research Service , United States Department of Agriculture, New Orleans, Louisiana 70124
| | - Matthew D Lebar
- Southern Regional Research Center, Agricultural Research Service , United States Department of Agriculture, New Orleans, Louisiana 70124
| | - Qijian Wei
- Southern Regional Research Center, Agricultural Research Service , United States Department of Agriculture, New Orleans, Louisiana 70124
| | - Brian Mack
- Southern Regional Research Center, Agricultural Research Service , United States Department of Agriculture, New Orleans, Louisiana 70124
| | - Peter S Ojiambo
- Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University , Raleigh, NC 27695
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19
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Petters-Vandresen DAL, Rossi BJ, Groenewald JZ, Crous PW, Machado MA, Stukenbrock EH, Glienke C. Mating-type locus rearrangements and shifts in thallism states in Citrus-associated Phyllosticta species. Fungal Genet Biol 2020; 144:103444. [PMID: 32822858 DOI: 10.1016/j.fgb.2020.103444] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/28/2020] [Accepted: 07/31/2020] [Indexed: 11/15/2022]
Abstract
Currently, eight Phyllosticta species are known to be associated with several Citrus hosts, incorporating diverse lifestyles: while some of them are endophytic (P. capitalensis and P. citribraziliensis), others are pathogenic (P. citriasiana, P. citricarpa, P. citrichinaensis and P. paracitricarpa). Sexual reproduction plays a key role in the interaction between these Phyllosticta species and their Citrus hosts, especially for the spread and persistence of the pathogenic species in the environment. Given this, differences in sexual reproduction strategies could be related to the differences in lifestyles. To evaluate this hypothesis, we characterized the mating-type loci of six Citrus-associated Phyllosticta species from whole genome assemblies. Mating-type genes in the Citrus-associated Phyllosticta species are highly variable in their sequence content, but the genomic locations and organization of the mating-type loci are conserved. Phyllosticta citriasiana, P. citribraziliensis, P. citricarpa and P. paracitricarpa are heterothallic, while P. capitalensis and P. citrichinaensis are homothallic. In addition, the P. citrichinaensis MAT1-2 idiomorph occurs in a separate location from the mating-type locus. Ancestral state reconstruction suggests that homothallism is the ancestral thallism state in Phyllosticta, with a shift to heterothallism in Phyllosticta species that are pathogenic to Citrus. Moreover, the homothallic strategies of P. capitalensis and P. citrichinaensis result from independent evolutionary events, as P. capitalensis locus likely represents the ancestral state, and P. citrichinaensis homothallism has risen through a reversion in a heterothallic ancestor and underwent remodelling events. As the pathogenic species P. citriasiana, P. citricarpa and P. paracitricarpa are heterothallic and incapable of selfing, disease management practices focused in preventing the occurrence of sexual reproduction could assist in the control of Citrus Black Spot and Citrus Tan Spot diseases. This study emphasizes the importance of studying Citrus-Phyllosticta interactions under evolutionary and genomic perspectives, as these approaches can provide valuable information about the association between Phyllosticta species and their hosts, and also serve as guidance for the improvement of disease management practices.
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Affiliation(s)
- Desirrê Alexia Lourenço Petters-Vandresen
- Laboratório de Bioprospecção e Genética Molecular de Microrganismos, Postgraduate Program in Genetics. Department of Genetics, Federal University of Paraná (UFPR), Centro Politécnico, Jardim das Américas, 81531-990 Curitiba, Paraná State, Brazil; Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Bruno Janoski Rossi
- Laboratório de Bioprospecção e Genética Molecular de Microrganismos, Postgraduate Program in Genetics. Department of Genetics, Federal University of Paraná (UFPR), Centro Politécnico, Jardim das Américas, 81531-990 Curitiba, Paraná State, Brazil
| | | | - Pedro W Crous
- Westerdijk Fungal Biodiversity Institute, Utrecht, Netherlands
| | | | - Eva H Stukenbrock
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany; Environmental Genomics, Christian-Albrechts University of Kiel, Kiel, Germany
| | - Chirlei Glienke
- Laboratório de Bioprospecção e Genética Molecular de Microrganismos, Postgraduate Program in Genetics. Department of Genetics, Federal University of Paraná (UFPR), Centro Politécnico, Jardim das Américas, 81531-990 Curitiba, Paraná State, Brazil.
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20
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Ortega‐Beltran A, Callicott KA, Cotty PJ. Founder events influence structures of Aspergillus flavus populations. Environ Microbiol 2020; 22:3522-3534. [PMID: 32515100 PMCID: PMC7496522 DOI: 10.1111/1462-2920.15122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 04/29/2020] [Accepted: 06/04/2020] [Indexed: 12/14/2022]
Abstract
In warm regions, agricultural fields are occupied by complex Aspergillus flavus communities composed of isolates in many vegetative compatibility groups (VCGs) with varying abilities to produce highly toxic, carcinogenic aflatoxins. Aflatoxin contamination is reduced with biocontrol products that enable atoxigenic isolates from atoxigenic VCGs to dominate the population. Shifts in VCG frequencies similar to those caused by the introduction of biocontrol isolates were detected in Sonora, Mexico, where biocontrol is not currently practiced. The shifts were attributed to founder events. Although VCGs reproduce clonally, significant diversity exists within VCGs. Simple sequence repeat (SSR) fingerprinting revealed that increased frequencies of VCG YV150 involved a single haplotype. This is consistent with a founder event. Additionally, great diversity was detected among 82 YV150 isolates collected over 20 years across Mexico and the United States. Thirty-six YV150 haplotypes were separated into two populations by Structure and SplitsTree analyses. Sixty-five percent of isolates had MAT1-1 and belonged to one population. The remaining had MAT1-2 and belonged to the second population. SSR alleles varied within populations, but recombination between populations was not detected despite co-occurrence at some locations. Results suggest that YV150 isolates with opposite mating-type have either strongly restrained or lost sexual reproduction among themselves.
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Affiliation(s)
- Alejandro Ortega‐Beltran
- School of Plant SciencesUniversity of ArizonaTucsonAZ85721USA
- International Institute of Tropical AgriculturePMB 5320 Oyo Road, IbadanNigeria
| | | | - Peter J. Cotty
- USDA‐ARSTucsonAZ85721USA
- School of Food Science and EngineeringOcean University of ChinaQingdaoShandong266003China
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21
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Ortega-Beltran A, Callicott KA, Cotty PJ. Founder events influence structures of Aspergillus flavus populations. Environ Microbiol 2020; 22:3522-3534. [PMID: 32515100 DOI: 10.1111/emi.15122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 04/29/2020] [Accepted: 06/04/2020] [Indexed: 05/25/2023]
Abstract
In warm regions, agricultural fields are occupied by complex Aspergillus flavus communities composed of isolates in many vegetative compatibility groups (VCGs) with varying abilities to produce highly toxic, carcinogenic aflatoxins. Aflatoxin contamination is reduced with biocontrol products that enable atoxigenic isolates from atoxigenic VCGs to dominate the population. Shifts in VCG frequencies similar to those caused by the introduction of biocontrol isolates were detected in Sonora, Mexico, where biocontrol is not currently practiced. The shifts were attributed to founder events. Although VCGs reproduce clonally, significant diversity exists within VCGs. Simple sequence repeat (SSR) fingerprinting revealed that increased frequencies of VCG YV150 involved a single haplotype. This is consistent with a founder event. Additionally, great diversity was detected among 82 YV150 isolates collected over 20 years across Mexico and the United States. Thirty-six YV150 haplotypes were separated into two populations by Structure and SplitsTree analyses. Sixty-five percent of isolates had MAT1-1 and belonged to one population. The remaining had MAT1-2 and belonged to the second population. SSR alleles varied within populations, but recombination between populations was not detected despite co-occurrence at some locations. Results suggest that YV150 isolates with opposite mating-type have either strongly restrained or lost sexual reproduction among themselves.
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Affiliation(s)
- Alejandro Ortega-Beltran
- School of Plant Sciences, University of Arizona, Tucson, AZ, 85721, USA
- International Institute of Tropical Agriculture, PMB 5320 Oyo Road, Ibadan, Nigeria
| | | | - Peter J Cotty
- USDA-ARS, Tucson, AZ, 85721, USA
- School of Food Science and Engineering, Ocean University of China, Qingdao, Shandong, 266003, China
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22
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Watarai N, Yamamoto N, Sawada K, Yamada T. Evolution of Aspergillus oryzae before and after domestication inferred by large-scale comparative genomic analysis. DNA Res 2020; 26:465-472. [PMID: 31755931 PMCID: PMC6993814 DOI: 10.1093/dnares/dsz024] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Accepted: 11/21/2019] [Indexed: 12/22/2022] Open
Abstract
Aspergillus oryzae is an industrially useful species, of which various strains have been identified; however, their genetic relationships remain unclear. A. oryzae was previously thought to be asexual and unable to undergo crossbreeding. However, recent studies revealed the sexual reproduction of Aspergillus flavus, a species closely related to A. oryzae. To investigate potential sexual reproduction in A. oryzae and evolutionary history among A. oryzae and A. flavus strains, we assembled 82 draft genomes of A. oryzae strains used practically. The phylogenetic tree of concatenated genes confirmed that A. oryzae was monophyletic and nested in one of the clades of A. flavus but formed several clades with different genomic structures. Our results suggest that A. oryzae strains have undergone multiple inter-genomic recombination events between A. oryzae ancestors, although sexual recombination among domesticated species did not appear to have occurred during the domestication process, at least in the past few decades. Through inter- and intra-cladal comparative analysis, we found that evolutionary pressure induced by the domestication of A. oryzae appears to selectively cause non-synonymous and gap mutations in genes involved in fermentation characteristics, as well as intra-genomic rearrangements, with the conservation of industrially useful catalytic enzyme-encoding genes.
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Affiliation(s)
- Naoki Watarai
- Department of Life Science and Technology, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Nozomi Yamamoto
- Department of Life Science and Technology, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | | | - Takuji Yamada
- Department of Life Science and Technology, Tokyo Institute of Technology, Tokyo 152-8550, Japan
- To whom correspondence should be addressed. Tel. +81 3 5734 3591. Fax. +81 3 5734 3591.
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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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Aflatoxin Biosynthesis and Genetic Regulation: A Review. Toxins (Basel) 2020; 12:toxins12030150. [PMID: 32121226 PMCID: PMC7150809 DOI: 10.3390/toxins12030150] [Citation(s) in RCA: 134] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/27/2020] [Accepted: 02/25/2020] [Indexed: 12/15/2022] Open
Abstract
The study of fungal species evolved radically with the development of molecular techniques and produced new evidence to understand specific fungal mechanisms such as the production of toxic secondary metabolites. Taking advantage of these technologies to improve food safety, the molecular study of toxinogenic species can help elucidate the mechanisms underlying toxin production and enable the development of new effective strategies to control fungal toxicity. Numerous studies have been made on genes involved in aflatoxin B1 (AFB1) production, one of the most hazardous carcinogenic toxins for humans and animals. The current review presents the roles of these different genes and their possible impact on AFB1 production. We focus on the toxinogenic strains Aspergillus flavus and A. parasiticus, primary contaminants and major producers of AFB1 in crops. However, genetic reports on A. nidulans are also included because of the capacity of this fungus to produce sterigmatocystin, the penultimate stable metabolite during AFB1 production. The aim of this review is to provide a general overview of the AFB1 enzymatic biosynthesis pathway and its link with the genes belonging to the AFB1 cluster. It also aims to illustrate the role of global environmental factors on aflatoxin production and the recent data that demonstrate an interconnection between genes regulated by these environmental signals and aflatoxin biosynthetic pathway.
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Sarrocco S, Mauro A, Battilani P. Use of Competitive Filamentous Fungi as an Alternative Approach for Mycotoxin Risk Reduction in Staple Cereals: State of Art and Future Perspectives. Toxins (Basel) 2019; 11:E701. [PMID: 31810316 PMCID: PMC6950288 DOI: 10.3390/toxins11120701] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/27/2019] [Accepted: 11/29/2019] [Indexed: 12/23/2022] Open
Abstract
Among plant fungal diseases, those affecting cereals represent a huge problem in terms of food security and safety. Cereals, such as maize and wheat, are very often targets of mycotoxigenic fungi. The limited availability of chemical plant protection products and physical methods to control mycotoxigenic fungi and to reduce food and feed mycotoxin contamination fosters alternative approaches, such as the use of beneficial fungi as an active ingredient of biological control products. Competitive interactions, including both exploitation and interference competition, between pathogenic and beneficial fungi, are generally recognized as mechanisms to control plant pathogens populations and to manage plant diseases. In the present review, two examples concerning the use of competitive beneficial filamentous fungi for the management of cereal diseases are discussed. The authors retrace the history of the well-established use of non-aflatoxigenic isolates of Aspergillus flavus to prevent aflatoxin contamination in maize and give an overview of the potential use of competitive beneficial filamentous fungi to manage Fusarium Head Blight on wheat and mitigate fusaria toxin contamination. Although important steps have been made towards the development of microorganisms as active ingredients of plant protection products, a reasoned revision of the registration rules is needed to significantly reduce the chemical based plant protection products in agriculture.
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Affiliation(s)
- Sabrina Sarrocco
- Department of Agriculture, Food and Environment, University of Pisa, 56124 Pisa, Italy;
| | - Antonio Mauro
- International Institute of Tropical Agriculture, P.O. Box 34441 Dar es Salaam, Tanzania;
| | - Paola Battilani
- Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, 29122 Piacenza, Italy
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Kim KU, Kim KM, Choi YH, Hurh BS, Lee I. Whole genome analysis of Aspergillus sojae SMF 134 supports its merits as a starter for soybean fermentation. J Microbiol 2019; 57:874-883. [PMID: 31250400 DOI: 10.1007/s12275-019-9152-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/13/2019] [Accepted: 05/16/2019] [Indexed: 10/26/2022]
Abstract
Aspergillus sojae is a koji (starter) mold that has been applied for food fermentation in Asia. The whole genome of A. sojae SMF 134, which was isolated from meju (Korean soybean fermented brick), was analyzed at the genomic level to evaluate its potential as a starter for soybean fermentation. The genome size was 40.1 Mbp, which was expected to be composed of eight chromosomes with 13,748 ORFs. Strain SMF 134 had a total of 151 protease genes, among which two more leucine aminopeptidase (lap) genes were found in addition to the previously known lap 1, and three γ-glutamyltranspeptidase (ggt) genes were newly identified. Such genomic characteristics of SMF 134 with many protease and flavor-related (lap and ggt) genes support its merits as a starter for soybean fermentation. In addition, this first complete genome of A. sojae will allow for further genetic studies to better understand the production of various enzymes, including proteases, LAPs, and GGTs, as well as other characteristics as a starter mold for soybean fermentation.
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Affiliation(s)
- Kang Uk Kim
- Department of Bio and Fermentation Convergence Technology, BK21 PLUS Project, Kookmin University, Seoul, 02707, Republic of Korea
| | - Kyung Min Kim
- Department of Bio and Fermentation Convergence Technology, BK21 PLUS Project, Kookmin University, Seoul, 02707, Republic of Korea
| | - Yong-Ho Choi
- Sempio Fermentation Research Center, Sempio Foods Company, Cheongju, 28156, Republic of Korea
| | - Byung-Serk Hurh
- Sempio Fermentation Research Center, Sempio Foods Company, Cheongju, 28156, Republic of Korea
| | - Inhyung Lee
- Department of Bio and Fermentation Convergence Technology, BK21 PLUS Project, Kookmin University, Seoul, 02707, Republic of Korea.
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27
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Lewis MH, Carbone I, Luis JM, Payne GA, Bowen KL, Hagan AK, Kemerait R, Heiniger R, Ojiambo PS. Biocontrol Strains Differentially Shift the Genetic Structure of Indigenous Soil Populations of Aspergillus flavus. Front Microbiol 2019; 10:1738. [PMID: 31417528 PMCID: PMC6685141 DOI: 10.3389/fmicb.2019.01738] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 07/15/2019] [Indexed: 01/22/2023] Open
Abstract
Biocontrol using non-aflatoxigenic strains of Aspergillus flavus has the greatest potential to mitigate aflatoxin contamination in agricultural produce. However, factors that influence the efficacy of biocontrol agents in reducing aflatoxin accumulation under field conditions are not well-understood. Shifts in the genetic structure of indigenous soil populations of A. flavus following application of biocontrol products Afla-Guard and AF36 were investigated to determine how these changes can influence the efficacy of biocontrol strains in reducing aflatoxin contamination. Soil samples were collected from maize fields in Alabama, Georgia, and North Carolina in 2012 and 2013 to determine changes in the population genetic structure of A. flavus in the soil following application of the biocontrol strains. A. flavus L was the most dominant species of Aspergillus section Flavi with a frequency ranging from 61 to 100%, followed by Aspergillus parasiticus that had a frequency of <35%. The frequency of A. flavus L increased, while that of A. parasiticus decreased after application of biocontrol strains. A total of 112 multilocus haplotypes (MLHs) were inferred from 1,282 isolates of A. flavus L using multilocus sequence typing of the trpC, mfs, and AF17 loci. A. flavus individuals belonging to the Afla-Guard MLH in the IB lineage were the most dominant before and after application of biocontrol strains, while individuals of the AF36 MLH in the IC lineage were either recovered in very low frequencies or not recovered at harvest. There were no significant (P > 0.05) differences in the frequency of individuals with MAT1-1 and MAT1-2 for clone-corrected MLH data, an indication of a recombining population resulting from sexual reproduction. Population mean mutation rates were not different across temporal and spatial scales indicating that mutation alone is not a driving force in observed multilocus sequence diversity. Clustering based on principal component analysis identified two distinct evolutionary lineages (IB and IC) across all three states. Additionally, patristic distance analysis revealed phylogenetic incongruency among single locus phylogenies which suggests ongoing genetic exchange and recombination. Levels of aflatoxin accumulation were very low except in North Carolina in 2012, where aflatoxin levels were significantly (P < 0.05) lower in grain from treated compared to untreated plots. Phylogenetic analysis showed that Afla-Guard was more effective than AF36 in shifting the indigenous soil populations of A. flavus toward the non-toxigenic or low aflatoxin producing IB lineage. These results suggest that Afla-Guard, which matches the genetic and ecological structure of indigenous soil populations of A. flavus in Alabama, Georgia, and North Carolina, is likely to be more effective in reducing aflatoxin accumulation and will also persist longer in the soil than AF36 in the southeastern United States.
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Affiliation(s)
- Mary H Lewis
- Department of Entomology and Plant Pathology, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC, United States
| | - Ignazio Carbone
- Department of Entomology and Plant Pathology, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC, United States
| | - Jane M Luis
- Department of Entomology and Plant Pathology, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC, United States
| | - Gary A Payne
- Department of Entomology and Plant Pathology, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC, United States
| | - Kira L Bowen
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | - Austin K Hagan
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | - Robert Kemerait
- Department of Plant Pathology, University of Georgia, Coastal Plain Experiment Station, Tifton, GA, United States
| | - Ron Heiniger
- Department of Crop Science, North Carolina State University, Raleigh, NC, United States
| | - Peter S Ojiambo
- Department of Entomology and Plant Pathology, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC, United States
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28
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Uka V, Moore GG, Arroyo-Manzanares N, Nebija D, De Saeger S, Diana Di Mavungu J. Secondary Metabolite Dereplication and Phylogenetic Analysis Identify Various Emerging Mycotoxins and Reveal the High Intra-Species Diversity in Aspergillus flavus. Front Microbiol 2019; 10:667. [PMID: 31024476 PMCID: PMC6461017 DOI: 10.3389/fmicb.2019.00667] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 03/18/2019] [Indexed: 12/18/2022] Open
Abstract
Aspergillus flavus is one of the most important mycotoxigenic species from the genus Aspergillus, due to its ability to synthesize the potent hepatocarcinogen, aflatoxin B1. Moreover, this fungus is capable of producing several other toxic metabolites from the class of indole-tetramates, non-ribosomal peptides, and indole-diterpenoids. Populations of A. flavus are characterized by considerable diversity in terms of morphological, functional and genetic features. Although for many years A. flavus was considered an asexual fungus, researchers have shown evidence that at best these fungi can exhibit a predominantly asexual existence. We now know that A. flavus contains functional genes for mating, uncovering sexuality as potential contributor for its diversification. Based on our results, we reconfirm that A. flavus is a predominant producer of B-type aflatoxins. Moreover, this fungus can decisively produce AFM1 and AFM2. We did not observe any clear relationship between mating-type genes and particular class of metabolites, probably other parameters such as sexual/asexual ratio should be investigated. A dynamic secondary metabolism was found also in strains intended to be used as biocontrol agents. In addition we succeeded to provide mass spectrometry fragmentation spectra for the most important classes of A. flavus metabolites, which will serve as identification cards for future studies. Both, metabolic and phylogenetic analysis proved a high intra-species diversity for A. flavus. These findings contribute to our understanding about the diversity of Aspergillus section Flavi species, raising the necessity for polyphasic approaches (morphological, metabolic, genetic, etc.) when dealing with this type of complex group of species.
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Affiliation(s)
- Valdet Uka
- Center of Excellence in Mycotoxicology and Public Health, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium.,Department of Pharmacy, Faculty of Medicine, University of Prishtina, Prishtina, Kosovo†
| | - Geromy G Moore
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, New Orleans, LA, United States
| | - Natalia Arroyo-Manzanares
- Department of Analytical Chemistry, Faculty of Chemistry, Regional Campus of International Excellence "Campus Mare-Nostrum", University of Murcia, Murcia, Spain
| | - Dashnor Nebija
- Department of Pharmacy, Faculty of Medicine, University of Prishtina, Prishtina, Kosovo†
| | - 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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Cullen M, Jacob ME, Cornish V, VanderSchel IQ, Cotter HVT, Cubeta MA, Carbone I, Gilger BC. Multi-locus DNA sequence analysis, antifungal agent susceptibility, and fungal keratitis outcome in horses from Southeastern United States. PLoS One 2019; 14:e0214214. [PMID: 30921394 PMCID: PMC6438541 DOI: 10.1371/journal.pone.0214214] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/09/2019] [Indexed: 11/21/2022] Open
Abstract
Morphological characterization and multi-locus DNA sequence analysis of fungal isolates obtained from 32 clinical cases of equine fungal keratitis (FK) was performed to identify species and determine associations with antifungal susceptibility, response to therapy and clinical outcome. Two species of Aspergillus (A. flavus and A. fumigatus) and three species of Fusarium (F. falciforme, F. keratoplasticum, and F. proliferatum) were the most common fungi isolated and identified from FK horses. Most (91%) equine FK Fusarium nested within the Fusarium solani species complex (FSSC) with nine genetically diverse strains/lineages, while 83% of equine FK Aspergillus nested within the A. flavus clade with three genetically diverse lineages. Fungal species and evolutionary lineage were not associated with clinical outcome. However, species of equine FK Fusarium were more likely (p = 0.045) to be associated with stromal keratitis. Species of Aspergillus were more susceptible to voriconazole and terbinafine than species of Fusarium, while species of Fusarium were more susceptible to thiabendazole than species of Aspergillus. At the species level, A. fumigatus and A. flavus were more susceptible to voriconazole and terbinafine than F. falciforme. Natamycin susceptibility was higher for F. falciforme and A. fumigatus compared to A. flavus. Furthermore, F. falciforme was more susceptible to thiabendazole than A. flavus and A. fumigatus. These observed associations of antifungal sensitivity to natamycin, terbinafine, and thiabendazole demonstrate the importance of fungal identification to the species rather than genus level. The results of this study suggest that treatment of equine FK with antifungal agents requires accurate fungal species identification.
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Affiliation(s)
- Megan Cullen
- Department of Clinical Sciences, NC State University, Raleigh, NC, United States of America
| | - Megan E. Jacob
- Department of Population Health and Pathobiology, NC State University, Raleigh, NC, United States of America
| | - Vicki Cornish
- Center for Integrated Fungal Research, College of Agriculture and Life Sciences, NC State University, Raleigh, NC, United States of America
| | - Ian Q. VanderSchel
- Center for Integrated Fungal Research, College of Agriculture and Life Sciences, NC State University, Raleigh, NC, United States of America
| | - Henry Van T. Cotter
- Center for Integrated Fungal Research, College of Agriculture and Life Sciences, NC State University, Raleigh, NC, United States of America
| | - Marc A. Cubeta
- Center for Integrated Fungal Research, College of Agriculture and Life Sciences, NC State University, Raleigh, NC, United States of America
| | - Ignazio Carbone
- Center for Integrated Fungal Research, College of Agriculture and Life Sciences, NC State University, Raleigh, NC, United States of America
| | - Brian C. Gilger
- Department of Clinical Sciences, NC State University, Raleigh, NC, United States of America
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Abstract
Several agricultural commodities can be infected by Aspergillus flavus, a fungus that can produce the carcinogen aflatoxin. Here, we report the whole-genome sequences for 20 georeferenced isolates collected from soil and corn under field conditions. This information contributes to an understanding of A. flavus population structure and dynamics in a field environment.
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Cary JW, Entwistle S, Satterlee T, Mack BM, Gilbert MK, Chang PK, Scharfenstein L, Yin Y, Calvo AM. The Transcriptional Regulator Hbx1 Affects the Expression of Thousands of Genes in the Aflatoxin-Producing Fungus Aspergillus flavus. G3 (BETHESDA, MD.) 2019; 9:167-178. [PMID: 30425054 PMCID: PMC6325891 DOI: 10.1534/g3.118.200870] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 11/09/2018] [Indexed: 12/21/2022]
Abstract
In filamentous fungi, homeobox proteins are conserved transcriptional regulators described to control conidiogenesis and fruiting body formation. Eight homeobox (hbx) genes are found in the genome of the aflatoxin-producing ascomycete, Aspergillus flavus While loss-of-function of seven of the eight genes had little to no effect on fungal growth and development, disruption of hbx1, resulted in aconidial colonies and lack of sclerotial production. Furthermore, the hbx1 mutant was unable to produce aflatoxins B1 and B2, cyclopiazonic acid and aflatrem. In the present study, hbx1 transcriptome analysis revealed that hbx1 has a broad effect on A. flavus gene expression, and the effect of hbx1 increases overtime, impacting more than five thousand protein-coding genes. Among the affected genes, those in the category of secondary metabolism (SM), followed by that of cellular transport, were the most affected. Specifically, regarding the effect of hbx1 on SM, we found that genes in 44 SM gene clusters where upregulated while 49 were downregulated in the absence of hbx1, including genes in the SM clusters responsible for the synthesis of asparasone, piperazine and aflavarin, all known to be associated with sclerotia. In addition, our study revealed that hbx1 affects the expression of other transcription factor genes involved in development, including the conidiation central regulatory pathway and flb genes.
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Affiliation(s)
- Jeffrey W Cary
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Sarah Entwistle
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois
| | - Timothy Satterlee
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois
| | - Brian M Mack
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Matthew K Gilbert
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Perng K Chang
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Leslie Scharfenstein
- Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana
| | - Yanbin Yin
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois
| | - Ana M Calvo
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois
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Metin B, Döğen A, Yıldırım E, de Hoog GS, Heitman J, Ilkit M. Mating type (MAT) locus and possible sexuality of the opportunistic pathogen Exophiala dermatitidis. Fungal Genet Biol 2019; 124:29-38. [PMID: 30611834 DOI: 10.1016/j.fgb.2018.12.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 12/27/2018] [Accepted: 12/30/2018] [Indexed: 11/27/2022]
Abstract
Sexual reproduction among the black yeasts is generally limited to environmental saprobic species and is rarely observed among opportunists in humans. To date, a complete sexual cycle has not been observed in Exophiala dermatitidis. In this study, we aimed to gain insight into the reproductive mode of E. dermatitidis by characterizing its mating type (MAT) locus, conducting MAT screening of environmental and clinical isolates, examining the expression of the MAT genes and analyzing the virulence of the isolates of different mating types. Similar to other members of the Pezizomycotina, the E. dermatitidis genome harbors a high mobility group (HMG) domain gene (MAT1-2-1) in the vicinity of the SLA2 and APN2 genes. The MAT loci of 74 E. dermatitidis isolates (11 clinical and 63 environmental) were screened by PCR, and the surrounding region was amplified using long-range PCR. Sequencing of the ∼ 12-kb PCR product of a MAT1-1 isolate revealed an α-box gene (MAT1-1-1). The MAT1-1 idiomorph was 3544-bp long and harbored the MAT1-1-1 and MAT1-1-4 genes. The MAT1-2 idiomorph was longer, 3771-bp, and harbored only the MAT1-2-1 gene. This structure suggests a heterothallic reproduction mode. The distribution of MAT among 74 isolates was ∼ 1:1 with a MAT1-1:MAT1-2 ratio of 35:39. RT-PCR analysis indicated that the MAT genes are transcribed. No significant difference was detected in the virulence of isolates representing different mating types using a Galleria mellonella model (P > 0.05). Collectively, E. dermatitidis is the first opportunistic black yeast in which both MAT idiomorphs have been characterized. The occurrence of isolates bearing both idiomorphs, their approximately equal distribution, and the expression of the MAT genes suggest that E. dermatitidis might reproduce sexually.
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Affiliation(s)
- Banu Metin
- Department of Food Engineering, Faculty of Engineering and Natural Sciences, Istanbul Sabahattin Zaim University, Istanbul, Turkey.
| | - Aylin Döğen
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Mersin University, Mersin, Turkey.
| | - Esra Yıldırım
- Department of Food Engineering, Faculty of Engineering and Natural Sciences, Istanbul Sabahattin Zaim University, Istanbul, Turkey.
| | - G Sybren de Hoog
- Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands; Center of Expertise in Mycology of Radboudumc/CWZ, Nijmegen, the Netherlands.
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA.
| | - Macit Ilkit
- Division of Mycology, Department of Microbiology, Faculty of Medicine, Çukurova University, Adana, Turkey.
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Singh P, Orbach MJ, Cotty PJ. Aspergillus texensis: A Novel Aflatoxin Producer with S Morphology from the United States. Toxins (Basel) 2018; 10:E513. [PMID: 30513994 PMCID: PMC6316697 DOI: 10.3390/toxins10120513] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/27/2018] [Accepted: 11/27/2018] [Indexed: 11/17/2022] Open
Abstract
Aflatoxins are carcinogenic metabolites produced primarily by fungi within Aspergillus section Flavi. These fungi infect a wide range of crops in warm regions. Molecular phylogenetic analyses of fungi with S morphology (average sclerotium size < 400 µm) within section Flavi collected from across the United States (US) resulted in the discovery of a novel aflatoxin-producing species, Aspergillus texensis. Aspergillus texensis was isolated from maize grown in Arkansas, Louisiana, and Texas, and from soils cropped to maize in Texas. Aspergillus texensis produces sparse conidia and abundant sclerotia on various culture media, and on maize. Physiological studies have revealed optimal growth on culture media at 35 °C. All isolates of A. texensis produced B and G aflatoxins, cyclopiazonic acid and aspergillic acid. Aspergillus texensis and A. flavus S strain morphotypes produced similar concentrations of total aflatoxins on maize (p > 0.05). Phylogenetic analyses of aflatoxin-producers based on partial gene sequences of the β-tubulin (0.9 kb), calmodulin (1.2 kb), and nitrate reductase (2.1 kb) genes placed A. texensis in a highly supported monophyletic clade closely related to A. minisclerotigenes and a previously reported unnamed lineage designated Lethal Aflatoxicosis Fungus.
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Affiliation(s)
- Pummi Singh
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, USA.
| | - Marc J Orbach
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, USA.
| | - Peter J Cotty
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, USA.
- USDA-ARS, 416 W Congress St, First Floor, Tucson, AZ 85701, USA.
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Abstract
Aspergillus nidulans has long-been used as a model organism to gain insights into the genetic basis of asexual and sexual developmental processes both in other members of the genus Aspergillus, and filamentous fungi in general. Paradigms have been established concerning the regulatory mechanisms of conidial development. However, recent studies have shown considerable genome divergence in the fungal kingdom, questioning the general applicability of findings from Aspergillus, and certain longstanding evolutionary theories have been questioned. The phylogenetic distribution of key regulatory elements of asexual reproduction in A. nidulans was investigated in a broad taxonomic range of fungi. This revealed that some proteins were well conserved in the Pezizomycotina (e.g. AbaA, FlbA, FluG, NsdD, MedA, and some velvet proteins), suggesting similar developmental roles. However, other elements (e.g. BrlA) had a more restricted distribution solely in the Eurotiomycetes, and it appears that the genetic control of sporulation seems to be more complex in the aspergilli than in some other taxonomic groups of the Pezizomycotina. The evolution of the velvet protein family is discussed based on the history of expansion and contraction events in the early divergent fungi. Heterologous expression of the A. nidulans abaA gene in Monascus ruber failed to induce development of complete conidiophores as seen in the aspergilli, but did result in increased conidial production. The absence of many components of the asexual developmental pathway from members of the Saccharomycotina supports the hypothesis that differences in the complexity of their spore formation is due in part to the increased diversity of the sporulation machinery evident in the Pezizomycotina. Investigations were also made into the evolution of sex and sexuality in the aspergilli. MAT loci were identified from the heterothallic Aspergillus (Emericella) heterothallicus and Aspergillus (Neosartorya) fennelliae and the homothallic Aspergillus pseudoglaucus (=Eurotium repens). A consistent architecture of the MAT locus was seen in these and other heterothallic aspergilli whereas much variation was seen in the arrangement of MAT loci in homothallic aspergilli. This suggested that it is most likely that the common ancestor of the aspergilli exhibited a heterothallic breeding system. Finally, the supposed prevalence of asexuality in the aspergilli was examined. Investigations were made using A. clavatus as a representative 'asexual' species. It was possible to induce a sexual cycle in A. clavatus given the correct MAT1-1 and MAT1-2 partners and environmental conditions, with recombination confirmed utilising molecular markers. This indicated that sexual reproduction might be possible in many supposedly asexual aspergilli and beyond, providing general insights into the nature of asexuality in fungi.
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Islam MS, Callicott KA, Mutegi C, Bandyopadhyay R, Cotty PJ. Aspergillus flavus resident in Kenya: High genetic diversity in an ancient population primarily shaped by clonal reproduction and mutation-driven evolution. FUNGAL ECOL 2018; 35:20-33. [PMID: 30283498 PMCID: PMC6131765 DOI: 10.1016/j.funeco.2018.05.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 12/30/2022]
Abstract
Aspergillus flavus has long been considered to be an asexual species. Although a sexual stage was recently reported for this species from in vitro studies, the amount of recombination ongoing in natural populations and the genetic distance across which meiosis occurs is largely unknown. In the current study, genetic diversity, reproduction and evolution of natural A. flavus populations endemic to Kenya were examined. A total of 2744 isolates recovered from 629 maize-field soils across southern Kenya in two consecutive seasons were characterized at 17 SSR loci, revealing high genetic diversity (9-72 alleles/locus and 2140 haplotypes). Clonal reproduction and persistence of clonal lineages predominated, with many identical haplotypes occurring in multiple soil samples and both seasons. Genetic analyses predicted three distinct lineages with linkage disequilibrium and evolutionary relationships among haplotypes within each lineage suggesting mutation-driven evolution followed by clonal reproduction. Low genetic differentiation among adjacent communities reflected frequent short distance dispersal.
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Affiliation(s)
- Md-Sajedul Islam
- Agricultural Research Service, United States Department of Agriculture, School of Plant Sciences, University of Arizona, Tucson, AZ, USA
| | - Kenneth A. Callicott
- Agricultural Research Service, United States Department of Agriculture, School of Plant Sciences, University of Arizona, Tucson, AZ, USA
| | - Charity Mutegi
- International Institute of Tropical Agriculture, Nairobi, Kenya
| | | | - Peter J. Cotty
- Agricultural Research Service, United States Department of Agriculture, School of Plant Sciences, University of Arizona, Tucson, AZ, USA
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Ojiambo PS, Battilani P, Cary JW, Blum BH, Carbone I. Cultural and Genetic Approaches to Manage Aflatoxin Contamination: Recent Insights Provide Opportunities for Improved Control. PHYTOPATHOLOGY 2018; 108:1024-1037. [PMID: 29869954 DOI: 10.1094/phyto-04-18-0134-rvw] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Aspergillus flavus is a morphologically complex species that can produce the group of polyketide derived carcinogenic and mutagenic secondary metabolites, aflatoxins, as well as other secondary metabolites such as cyclopiazonic acid and aflatrem. Aflatoxin causes aflatoxicosis when aflatoxins are ingested through contaminated food and feed. In addition, aflatoxin contamination is a major problem, from both an economic and health aspect, in developing countries, especially Asia and Africa, where cereals and peanuts are important food crops. Earlier measures for control of A. flavus infection and consequent aflatoxin contamination centered on creating unfavorable environments for the pathogen and destroying contaminated products. While development of atoxigenic (nonaflatoxin producing) strains of A. flavus as viable commercial biocontrol agents has marked a unique advance for control of aflatoxin contamination, particularly in Africa, new insights into the biology and sexuality of A. flavus are now providing opportunities to design improved atoxigenic strains for sustainable biological control of aflatoxin. Further, progress in the use of molecular technologies such as incorporation of antifungal genes in the host and host-induced gene silencing, is providing knowledge that could be harnessed to develop germplasm that is resistant to infection by A. flavus and aflatoxin contamination. This review summarizes the substantial progress that has been made to understand the biology of A. flavus and mitigate aflatoxin contamination with emphasis on maize. Concepts developed to date can provide a basis for future research efforts on the sustainable management of aflatoxin contamination.
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Affiliation(s)
- Peter S Ojiambo
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
| | - Paola Battilani
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
| | - Jeffrey W Cary
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
| | - Burt H Blum
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
| | - Ignazio Carbone
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
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Liu W, Chen L, Cai Y, Zhang Q, Bian Y. Opposite Polarity Monospore Genome De Novo Sequencing and Comparative Analysis Reveal the Possible Heterothallic Life Cycle of Morchella importuna. Int J Mol Sci 2018; 19:E2525. [PMID: 30149649 PMCID: PMC6164635 DOI: 10.3390/ijms19092525] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 08/18/2018] [Accepted: 08/21/2018] [Indexed: 02/04/2023] Open
Abstract
Morchella is a popular edible fungus worldwide due to its rich nutrition and unique flavor. Many research efforts were made on the domestication and cultivation of Morchella all over the world. In recent years, the cultivation of Morchella was successfully commercialized in China. However, the biology is not well understood, which restricts the further development of the morel fungus cultivation industry. In this paper, we performed de novo sequencing and assembly of the genomes of two monospores with a different mating type (M04M24 and M04M26) isolated from the commercially cultivated strain M04. Gene annotation and comparative genome analysis were performed to study differences in CAZyme (Carbohydrate-active enzyme) enzyme content, transcription factors, duplicated sequences, structure of mating type sites, and differences at the gene and functional levels between the two monospore strains of M. importuna. Results showed that the de novo assembled haploid M04M24 and M04M26 genomes were 48.98 and 51.07 Mb, respectively. A complete fine physical map of M. importuna was obtained from genome coverage and gene completeness evaluation. A total of 10,852 and 10,902 common genes and 667 and 868 endemic genes were identified from the two monospore strains, respectively. The Gene Ontology (GO) and KAAS (KEGG Automatic Annotation Serve) enrichment analyses showed that the endemic genes performed different functions. The two monospore strains had 99.22% collinearity with each other, accompanied with certain position and rearrangement events. Analysis of complete mating-type loci revealed that the two monospore M. importuna strains contained an independent mating-type structure and remained conserved in sequence and location. The phylogenetic and divergence time of M. importuna was analyzed at the whole-genome level for the first time. The bifurcation time of morel and tuber was estimated to be 201.14 million years ago (Mya); the two monospore strains with a different mating type represented the evolution of different nuclei, and the single copy homologous genes between them were also different due to a genetic differentiation distance about 0.65 Mya. Compared with truffles, M. importuna had an extension of 28 clusters of orthologous genes (COGs) and a contraction of two COGs. The two different polar nuclei with different degrees of contraction and expansion suggested that they might have undergone different evolutionary processes. The different mating-type structures, together with the functional clustering and enrichment analysis results of the endemic genes of the two different polar nuclei, imply that M. importuna might be a heterothallic fungus and the interaction between the endemic genes may be necessary for its complete life history. Studies on the genome of M. importuna facilitate a better understanding of morel biology and evolution.
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Affiliation(s)
- Wei Liu
- Institute of Applied Mycology, Plant Science and Technology College, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Agro-Microbial Resource Comprehensive Utilization, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China.
| | - LianFu Chen
- Institute of Applied Mycology, Plant Science and Technology College, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Agro-Microbial Resource Comprehensive Utilization, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China.
| | - YingLi Cai
- Institute of Applied Mycology, Plant Science and Technology College, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Agro-Microbial Resource Comprehensive Utilization, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China.
| | - QianQian Zhang
- Institute of Applied Mycology, Plant Science and Technology College, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Agro-Microbial Resource Comprehensive Utilization, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China.
| | - YinBing Bian
- Institute of Applied Mycology, Plant Science and Technology College, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Agro-Microbial Resource Comprehensive Utilization, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China.
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Young CA, Bock CH, Charlton ND, Mattupalli C, Krom N, Bowen JK, Templeton M, Plummer KM, Wood BW. Evidence for Sexual Reproduction: Identification, Frequency, and Spatial Distribution of Venturia effusa (Pecan Scab) Mating Type Idiomorphs. PHYTOPATHOLOGY 2018; 108:837-846. [PMID: 29381450 DOI: 10.1094/phyto-07-17-0233-r] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Venturia effusa (syn. Fusicladium effusum), causal agent of pecan scab, is the most prevalent pathogen of pecan (Carya illinoinensis), causing severe yield losses in the southeastern United States. V. effusa is currently known only by its asexual (conidial) stage. However, the degree and distribution of genetic diversity observed within and among populations of V. effusa are typical of a sexually reproducing fungal pathogen, and comparable with other dothideomycetes with a known sexual stage, including the closely related apple scab pathogen, V. inaequalis. Using the mating type (MAT) idiomorphs from V. inaequalis, we identified a single MAT gene, MAT1-1-1, in a draft genome of V. effusa. The MAT1-1-1 locus is flanked by two conserved genes encoding a DNA lyase (APN2) and a hypothetical protein. The MAT locus spanning the flanking genes was amplified and sequenced from a subset of 14 isolates, of which 7 contained MAT1-1-1 and the remaining samples contained MAT1-2-1. A multiplex polymerase chain reaction screen was developed to amplify MAT1-1-1, MAT1-2-1, and a conserved reference gene encoding β-tubulin, and used to screen 784 monoconidial isolates of V. effusa collected from 11 populations of pecan across the southeastern United States. A hierarchical sampling protocol representing region, orchard, and tree allowed for analysis of MAT structure at different spatial scales. Analysis of this collection revealed the frequency of the MAT idiomorphs is in a 1:1 equilibrium of MAT1-1:MAT1-2. The apparent equilibrium of the MAT idiomorphs provides impetus for a renewed effort to search for the sexual stage of V. effusa. [Formula: see text] Copyright © 2018 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
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Affiliation(s)
- Carolyn A Young
- First, third, fourth, and fifth authors: Noble Research Institute, LLC., Ardmore, OK 73401; second and ninth authors: United States Department of Agriculture-Agricultural Research Service Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008; sixth and seventh authors: The New Zealand Institute for Plant & Food Research, Auckland, New Zealand; seventh author: The School of Biological Sciences, University of Auckland, New Zealand; eighth author: Department of Animal, Plant and Soil Sciences, AgriBio, AgriBiosciences Research Centre, La Trobe University, 3086, Victoria, Australia
| | - Clive H Bock
- First, third, fourth, and fifth authors: Noble Research Institute, LLC., Ardmore, OK 73401; second and ninth authors: United States Department of Agriculture-Agricultural Research Service Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008; sixth and seventh authors: The New Zealand Institute for Plant & Food Research, Auckland, New Zealand; seventh author: The School of Biological Sciences, University of Auckland, New Zealand; eighth author: Department of Animal, Plant and Soil Sciences, AgriBio, AgriBiosciences Research Centre, La Trobe University, 3086, Victoria, Australia
| | - Nikki D Charlton
- First, third, fourth, and fifth authors: Noble Research Institute, LLC., Ardmore, OK 73401; second and ninth authors: United States Department of Agriculture-Agricultural Research Service Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008; sixth and seventh authors: The New Zealand Institute for Plant & Food Research, Auckland, New Zealand; seventh author: The School of Biological Sciences, University of Auckland, New Zealand; eighth author: Department of Animal, Plant and Soil Sciences, AgriBio, AgriBiosciences Research Centre, La Trobe University, 3086, Victoria, Australia
| | - Chakradhar Mattupalli
- First, third, fourth, and fifth authors: Noble Research Institute, LLC., Ardmore, OK 73401; second and ninth authors: United States Department of Agriculture-Agricultural Research Service Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008; sixth and seventh authors: The New Zealand Institute for Plant & Food Research, Auckland, New Zealand; seventh author: The School of Biological Sciences, University of Auckland, New Zealand; eighth author: Department of Animal, Plant and Soil Sciences, AgriBio, AgriBiosciences Research Centre, La Trobe University, 3086, Victoria, Australia
| | - Nick Krom
- First, third, fourth, and fifth authors: Noble Research Institute, LLC., Ardmore, OK 73401; second and ninth authors: United States Department of Agriculture-Agricultural Research Service Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008; sixth and seventh authors: The New Zealand Institute for Plant & Food Research, Auckland, New Zealand; seventh author: The School of Biological Sciences, University of Auckland, New Zealand; eighth author: Department of Animal, Plant and Soil Sciences, AgriBio, AgriBiosciences Research Centre, La Trobe University, 3086, Victoria, Australia
| | - Joanna K Bowen
- First, third, fourth, and fifth authors: Noble Research Institute, LLC., Ardmore, OK 73401; second and ninth authors: United States Department of Agriculture-Agricultural Research Service Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008; sixth and seventh authors: The New Zealand Institute for Plant & Food Research, Auckland, New Zealand; seventh author: The School of Biological Sciences, University of Auckland, New Zealand; eighth author: Department of Animal, Plant and Soil Sciences, AgriBio, AgriBiosciences Research Centre, La Trobe University, 3086, Victoria, Australia
| | - Matthew Templeton
- First, third, fourth, and fifth authors: Noble Research Institute, LLC., Ardmore, OK 73401; second and ninth authors: United States Department of Agriculture-Agricultural Research Service Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008; sixth and seventh authors: The New Zealand Institute for Plant & Food Research, Auckland, New Zealand; seventh author: The School of Biological Sciences, University of Auckland, New Zealand; eighth author: Department of Animal, Plant and Soil Sciences, AgriBio, AgriBiosciences Research Centre, La Trobe University, 3086, Victoria, Australia
| | - Kim M Plummer
- First, third, fourth, and fifth authors: Noble Research Institute, LLC., Ardmore, OK 73401; second and ninth authors: United States Department of Agriculture-Agricultural Research Service Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008; sixth and seventh authors: The New Zealand Institute for Plant & Food Research, Auckland, New Zealand; seventh author: The School of Biological Sciences, University of Auckland, New Zealand; eighth author: Department of Animal, Plant and Soil Sciences, AgriBio, AgriBiosciences Research Centre, La Trobe University, 3086, Victoria, Australia
| | - Bruce W Wood
- First, third, fourth, and fifth authors: Noble Research Institute, LLC., Ardmore, OK 73401; second and ninth authors: United States Department of Agriculture-Agricultural Research Service Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008; sixth and seventh authors: The New Zealand Institute for Plant & Food Research, Auckland, New Zealand; seventh author: The School of Biological Sciences, University of Auckland, New Zealand; eighth author: Department of Animal, Plant and Soil Sciences, AgriBio, AgriBiosciences Research Centre, La Trobe University, 3086, Victoria, Australia
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Characterization and competitive ability of non-aflatoxigenic Aspergillus flavus isolated from the maize agro-ecosystem in Argentina as potential aflatoxin biocontrol agents. Int J Food Microbiol 2018; 277:58-63. [PMID: 29684766 DOI: 10.1016/j.ijfoodmicro.2018.04.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 03/26/2018] [Accepted: 04/13/2018] [Indexed: 12/17/2022]
Abstract
Aspergillus flavus is an opportunistic pathogen and may produce aflatoxins in maize, one of the most important crops in Argentina. A promising strategy to reduce aflatoxin accumulation is the biological control based on competitive exclusion. In order to select potential biocontrol agents among isolates from the maize growing region in Argentina, a total of 512 A. flavus strains were isolated from maize kernels and soil samples. Thirty-six per cent of the isolates from maize kernels did not produce detectable levels of aflatoxins, while 73% of the isolates from soil were characterized as non-aflatoxin producers. Forty percent and 49% of the isolates from maize kernels and soil samples, respectively, were not producers of cyclopiazonic acid (CPA). Sclerotia morphology was evaluated using Czapek Dox media. Eighty-six per cent of the isolates from maize kernels and 85% of the isolates from soil samples were L sclerotia morphotype (average diameter > 400 μm). The remaining isolates did not produce sclerotia. All isolates had MAT 1-1 idiomorph. The competitive ability of 9 non aflatoxigenic strains, 4 CPA(+) and 5 CPA(-), was evaluated in co-inoculations of maize kernels with an aflatoxigenic strain. All evaluated strains significantly (p < 0.05) reduced aflatoxin contamination in maize kernels. The aflatoxin B1 (AFB1) reduction ranged from 6 to 60%. The strain A. flavus ARG5/30 isolated from maize kernels would be a good candidate as a potential biocontrol agent to be used in maize, since it was characterized as neither aflatoxin nor CPA producer, morphotype L, MAT 1-1 idiomorph, and reduced AFB1 content in maize kernels by 59%. This study showed the competitive ability of potential aflatoxin biocontrol agents to be evaluated under field trials in a maize agro-ecosystem in Argentina.
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Development of a droplet digital PCR assay for population analysis of aflatoxigenic and atoxigenic Aspergillus flavus mixtures in soil. Mycotoxin Res 2018; 34:187-194. [PMID: 29582253 DOI: 10.1007/s12550-018-0313-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 03/08/2018] [Accepted: 03/13/2018] [Indexed: 10/17/2022]
Abstract
Aflatoxin B1 is a potent hepatotoxin and carcinogen that poses a serious safety hazard to both humans and animals. Aspergillus flavus is the most common aflatoxin-producing species on corn, cotton, peanuts, and tree nuts. Application of atoxigenic strains to compete against aflatoxigenic strains of A. flavus has emerged as one of the most practical strategies for ameliorating aflatoxin contamination in food. Genes directly involved in aflatoxin biosynthesis are clustered on an 82-kb region of the genome. Three atoxigenic strains (CA12, M34, and AF123) were each paired with each of four aflatoxigenic strains (CA28, CA42, CA90, and M52), inoculated into soil and incubated at 28 °C for 2 weeks and 1 month. TaqMan probes, omtA-FAM, and norA-HEX were designed for developing a droplet digital PCR (ddPCR) assay to analyze the soil population of mixtures of A. flavus strains. DNA was extracted from each soil sample and used for ddPCR assays. The data indicated that competition between atoxigenic and aflatoxigenic was strain dependent. Variation in competitive ability among different strains of A. flavus influenced the population reduction of the aflatoxigenic strain by the atoxigenic strain. Higher ratios of atoxigenic to aflatoxigenic strains increased soil population of atoxigenic strains. This is the first study to demonstrate the utility of ddPCR to quantify mixtures of both atoxigenic and aflatoxigenic A. flavus strains in soil and allows for rapid and accurate determination of population sizes of atoxigenic and aflatoxigenic strains. This method eliminates the need for isolation and identification of individual fungal isolates from experimental soil samples.
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Moore GG, Mack BM, Beltz SB, Puel O. Genome sequence of an aflatoxigenic pathogen of Argentinian peanut, Aspergillus arachidicola. BMC Genomics 2018; 19:189. [PMID: 29523080 PMCID: PMC5845213 DOI: 10.1186/s12864-018-4576-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 03/02/2018] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Aspergillus arachidicola is an aflatoxigenic fungal species, first isolated from the leaves of a wild peanut species native to Argentina. It has since been reported in maize, Brazil nut and human sputum samples. This aflatoxigenic species is capable of secreting both B and G aflatoxins, similar to A. parasiticus and A. nomius. It has other characteristics that may result in its misidentification as one of several other section Flavi species. This study offers a preliminary analysis of the A. arachidicola genome. RESULTS In this study we sequenced the genome of the A. arachidicola type strain (CBS 117610) and found its genome size to be 38.9 Mb, and its number of predicted genes to be 12,091, which are values comparable to those in other sequenced Aspergilli. A comparison of 57 known Aspergillus secondary metabolite gene clusters, among closely-related aflatoxigenic species, revealed nearly half were predicted to exist in the type strain of A. arachidicola. Of its predicted genes, 691 were identified as unique to the species and 60% were assigned Gene Ontology terms using BLAST2GO. Phylogenomic inference shows CBS 117610 sharing a most recent common ancestor with A. parasiticus. Finally, BLAST query of A. flavus mating-type idiomorph sequences to this strain revealed the presence of a single mating-type (MAT1-1) idiomorph. CONCLUSIONS Based on A. arachidicola morphological, genetic and chemotype similarities with A. flavus and A. parasiticus, sequencing the genome of A. arachidicola will contribute to our understanding of the evolutionary relatedness among aflatoxigenic fungi.
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Affiliation(s)
- Geromy G. Moore
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, 1100 Robert E Lee Blvd, New Orleans, Louisiana, 70124 USA
| | - Brian M. Mack
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, 1100 Robert E Lee Blvd, New Orleans, Louisiana, 70124 USA
| | - Shannon B. Beltz
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, 1100 Robert E Lee Blvd, New Orleans, Louisiana, 70124 USA
| | - Olivier Puel
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
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The 14-3-3 Protein Homolog ArtA Regulates Development and Secondary Metabolism in the Opportunistic Plant Pathogen Aspergillus flavus. Appl Environ Microbiol 2018; 84:AEM.02241-17. [PMID: 29247055 PMCID: PMC5812931 DOI: 10.1128/aem.02241-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 12/06/2017] [Indexed: 01/07/2023] Open
Abstract
The opportunistic plant-pathogenic fungus Aspergillus flavus produces carcinogenic mycotoxins termed aflatoxins (AF). Aflatoxin contamination of agriculturally important crops, such as maize, peanut, sorghum, and tree nuts, is responsible for serious adverse health and economic impacts worldwide. In order to identify possible genetic targets to reduce AF contamination, we have characterized the artA gene, encoding a putative 14-3-3 homolog in A. flavus The artA deletion mutant presents a slight decrease in vegetative growth and alterations in morphological development and secondary metabolism. Specifically, artA affects conidiation, and this effect is influenced by the type of substrate and culture condition. In addition, normal levels of artA are required for sclerotial development. Importantly, artA negatively regulates AF production as well as the concomitant expression of genes in the AF gene cluster. An increase in AF is also observed in seeds infected with the A. flavus strain lacking artA Furthermore, the expression of other secondary metabolite genes is also artA dependent, including genes in the cyclopiazonic acid (CPA) and ustiloxin gene clusters, in this agriculturally important fungus.IMPORTANCE In the current study, artA, which encodes a 14-3-3 homolog, was characterized in the agriculturally and medically important fungus Aspergillus flavus, specifically, its possible role governing sporulation, formation of resistant structures, and secondary metabolism. The highly conserved artA is necessary for normal fungal morphogenesis in an environment-dependent manner, affecting the balance between production of conidiophores and the formation of resistant structures that are necessary for the dissemination and survival of this opportunistic pathogen. This study reports a 14-3-3 protein affecting secondary metabolism in filamentous fungi. Importantly, artA regulates the biosynthesis of the potent carcinogenic compound aflatoxin B1 (AFB1) as well as the production of other secondary metabolites.
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Mauro A, Garcia-Cela E, Pietri A, Cotty PJ, Battilani P. Biological Control Products for Aflatoxin Prevention in Italy: Commercial Field Evaluation of Atoxigenic Aspergillus flavus Active Ingredients. Toxins (Basel) 2018; 10:E30. [PMID: 29304008 PMCID: PMC5793117 DOI: 10.3390/toxins10010030] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 12/23/2017] [Accepted: 01/02/2018] [Indexed: 11/16/2022] Open
Abstract
Since 2003, non-compliant aflatoxin concentrations have been detected in maize produced in Italy. The most successful worldwide experiments in aflatoxin prevention resulted from distribution of atoxigenic strains of Aspergillusflavus to displace aflatoxin-producers during crop development. The displacement results in lower aflatoxin concentrations in harvested grain. The current study evaluated in field performances of two atoxigenic strains of A. flavus endemic to Italy in artificially inoculated maize ears and in naturally contaminated maize. Co-inoculation of atoxigenic strains with aflatoxin producers resulted in highly significant reductions in aflatoxin concentrations (>90%) in both years only with atoxigenic strain A2085. The average percent reduction in aflatoxin B₁ concentration in naturally contaminated maize fields was 92.3%, without significant differences in fumonisins between treated and control maize. The vegetative compatibility group of A2085 was the most frequently recovered A. flavus in both treated and control plots (average 61.9% and 53.5% of the A. flavus, respectively). A2085 was therefore selected as an active ingredient for biocontrol products and deposited under provisions of the Budapest Treaty in the Belgian Co-Ordinated Collections of Micro-Organisms (BCCM/MUCL) collection (accession MUCL54911). Further work on development of A2085 as a tool for preventing aflatoxin contamination in maize produced in Italy is ongoing with the commercial product named AF-X1™.
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Affiliation(s)
- Antonio Mauro
- International Institute of Tropical Agriculture, P.O. Box 34441 Dar es Salaam, Tanzania.
| | - Esther Garcia-Cela
- Applied Mycology Group, Environment and AgriFood Theme, Cranfield University, Cranfield, Bedford MK43 0AL, UK.
| | - Amedeo Pietri
- Institute of Food Science and Nutrition, Università Cattolica del Sacro Cuore, 29100 Piacenza, Italy.
| | - Peter J Cotty
- United States Department of Agriculture, Agricultural Research Service, School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA.
| | - Paola Battilani
- Department Sustainable Crop Production, Università Cattolica del Sacro Cuore, 29100 Piacenza, Italy.
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Abstract
Approximately 20% of species in the fungal kingdom are only known to reproduce by asexual means despite the many supposed advantages of sexual reproduction. However, in recent years, sexual cycles have been induced in a series of emblematic "asexual" species. We describe how these discoveries were made, building on observations of evidence for sexual potential or "cryptic sexuality" from population genetic analyses; the presence, distribution, and functionality of mating-type genes; genome analyses revealing the presence of genes linked to sexuality; the functionality of sex-related genes; and formation of sex-related developmental structures. We then describe specific studies that led to the discovery of mating and sex in certain Candida, Aspergillus, Penicillium, and Trichoderma species and discuss the implications of sex including the beneficial exploitation of the sexual cycle. We next consider whether there might be any truly asexual fungal species. We suggest that, although rare, imperfect fungi may genuinely be present in nature and that certain human activities, combined with the genetic flexibility that is a hallmark of the fungal kingdom, might favor the evolution of asexuality under certain conditions. Finally, we argue that fungal species should not be thought of as simply asexual or sexual, but rather as being composed of isolates on a continuum of sexual fertility.
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Nieuwenhuis BPS, James TY. The frequency of sex in fungi. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0540. [PMID: 27619703 DOI: 10.1098/rstb.2015.0540] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2016] [Indexed: 12/16/2022] Open
Abstract
Fungi are a diverse group of organisms with a huge variation in reproductive strategy. While almost all species can reproduce sexually, many reproduce asexually most of the time. When sexual reproduction does occur, large variation exists in the amount of in- and out-breeding. While budding yeast is expected to outcross only once every 10 000 generations, other fungi are obligate outcrossers with well-mixed panmictic populations. In this review, we give an overview of the costs and benefits of sexual and asexual reproduction in fungi, and the mechanisms that evolved in fungi to reduce the costs of either mode. The proximate molecular mechanisms potentiating outcrossing and meiosis appear to be present in nearly all fungi, making them of little use for predicting outcrossing rates, but also suggesting the absence of true ancient asexual lineages. We review how population genetic methods can be used to estimate the frequency of sex in fungi and provide empirical data that support a mixed mode of reproduction in many species with rare to frequent sex in between rounds of mitotic reproduction. Finally, we highlight how these estimates might be affected by the fungus-specific mechanisms that evolved to reduce the costs of sexual and asexual reproduction.This article is part of the themed issue 'Weird sex: the underappreciated diversity of sexual reproduction'.
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Affiliation(s)
- Bart P S Nieuwenhuis
- Department of Evolutionary Biology, Uppsala University, Norbyvägen 18D, 752 36 Uppsala, Sweden
| | - Timothy Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, 830 North University, Ann Arbor, MI 48109-1048, USA
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Carvajal-Campos A, Manizan AL, Tadrist S, Akaki DK, Koffi-Nevry R, Moore GG, Fapohunda SO, Bailly S, Montet D, Oswald IP, Lorber S, Brabet C, Puel O. Aspergillus korhogoensis, a Novel Aflatoxin Producing Species from the Côte d'Ivoire. Toxins (Basel) 2017; 9:E353. [PMID: 29088078 PMCID: PMC5705968 DOI: 10.3390/toxins9110353] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 10/13/2017] [Accepted: 10/26/2017] [Indexed: 12/12/2022] Open
Abstract
Several strains of a new aflatoxigenic species of Aspergillus, A. korhogoensis, were isolated in the course of a screening study involving species from section Flavi found contaminating peanuts (Arachis hypogaea) and peanut paste in the Côte d'Ivoire. Based on examination of four isolates, this new species is described using a polyphasic approach. A concatenated alignment comprised of nine genes (ITS, benA, cmdA, mcm7, amdS, rpb1, preB, ppgA, and preA) was subjected to phylogenetic analysis, and resulted in all four strains being inferred as a distinct clade. Characterization of mating type for each strain revealed A. korhogoensis as a heterothallic species, since three isolates exhibited a singular MAT1-1 locus and one isolate exhibited a singular MAT1-2 locus. Morphological and physiological characterizations were also performed based on their growth on various types of media. Their respective extrolite profiles were characterized using LC/HRMS, and showed that this new species is capable of producing B- and G-aflatoxins, aspergillic acid, cyclopiazonic acid, aflavarins, and asparasones, as well as other metabolites. Altogether, our results confirm the monophyly of A. korhogoensis, and strengthen its position in the A. flavus clade, as the sister taxon of A. parvisclerotigenus.
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Affiliation(s)
- Amaranta Carvajal-Campos
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - Ama Lethicia Manizan
- Laboratoire de Biotechnologie et Microbiologie des Aliments, UFR des Sciences et Technologie des Aliments, Université Nangui Abrogoua, 02 BP 801 Abidjan, Côte d'Ivoire.
| | - Souria Tadrist
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - David Koffi Akaki
- Laboratoire des Procédés Industriels de Synthèse, de l'Environnement et des Energies Nouvelles, Département Génie Chimique et Agro-alimentaire, Institut National Polytechnique Félix Houphouët-Boigny, BP 1313 Yamoussoukro, Côte d'Ivoire.
| | - Rose Koffi-Nevry
- Laboratoire de Biotechnologie et Microbiologie des Aliments, UFR des Sciences et Technologie des Aliments, Université Nangui Abrogoua, 02 BP 801 Abidjan, Côte d'Ivoire.
| | - Geromy G Moore
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, New Orleans, LA 70179, USA.
| | - Stephen O Fapohunda
- Department of Microbiology, Babcock University, 23401 Ilishan Remo, Nigeria.
| | - Sylviane Bailly
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - Didier Montet
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD)-Département PERSYST-UMR QualiSud, 34398 Montpellier, France.
| | - Isabelle P Oswald
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - Sophie Lorber
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - Catherine Brabet
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD)-Département PERSYST-UMR QualiSud, 34398 Montpellier, France.
| | - Olivier Puel
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
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Moore GG, Olarte RA, Horn BW, Elliott JL, Singh R, O'Neal CJ, Carbone I. Global population structure and adaptive evolution of aflatoxin-producing fungi. Ecol Evol 2017; 7:9179-9191. [PMID: 29152206 PMCID: PMC5677503 DOI: 10.1002/ece3.3464] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 07/28/2017] [Accepted: 08/31/2017] [Indexed: 12/16/2022] Open
Abstract
Aflatoxins produced by several species in Aspergillus section Flavi are a significant problem in agriculture and a continuous threat to human health. To provide insights into the biology and global population structure of species in section Flavi, a total of 1,304 isolates were sampled across six species (A. flavus, A. parasiticus, A. nomius, A. caelatus, A. tamarii, and A. alliaceus) from single fields in major peanut‐growing regions in Georgia (USA), Australia, Argentina, India, and Benin (Africa). We inferred maximum‐likelihood phylogenies for six loci, both combined and separately, including two aflatoxin cluster regions (aflM/alfN and aflW/aflX) and four noncluster regions (amdS, trpC, mfs and MAT), to examine population structure and history. We also employed principal component and STRUCTURE analysis to identify genetic clusters and their associations with six different categories (geography, species, precipitation, temperature, aflatoxin chemotype profile, and mating type). Overall, seven distinct genetic clusters were inferred, some of which were more strongly structured by G chemotype diversity than geography. Populations of A. flavus S in Benin were genetically distinct from all other section Flavi species for the loci examined, which suggests genetic isolation. Evidence of trans‐speciation within two noncluster regions, whereby A. flavus SBG strains from Australia share haplotypes with either A. flavus or A. parasiticus, was observed. Finally, while clay soil and precipitation may influence species richness in Aspergillus section Flavi, other region‐specific environmental and genetic parameters must also be considered.
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Affiliation(s)
- Geromy G Moore
- Southern Regional Research Center Agricultural Research Service U.S. Department of Agriculture New Orleans LA USA
| | - Rodrigo A Olarte
- Department of Plant Biology University of Minnesota St. Paul MN USA
| | - Bruce W Horn
- Department of Agriculture Agricultural Research Service National Peanut Research Laboratory Dawson GA USA
| | - Jacalyn L Elliott
- Department of Entomology and Plant Pathology Center for Integrated Fungal Research North Carolina State University Raleigh NC USA
| | - Rakhi Singh
- Department of Entomology and Plant Pathology Center for Integrated Fungal Research North Carolina State University Raleigh NC USA
| | - Carolyn J O'Neal
- Department of Entomology and Plant Pathology Center for Integrated Fungal Research North Carolina State University Raleigh NC USA
| | - Ignazio Carbone
- Department of Entomology and Plant Pathology Center for Integrated Fungal Research North Carolina State University Raleigh NC USA
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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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49
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de Vries RP, Riley R, Wiebenga A, Aguilar-Osorio G, Amillis S, Uchima CA, Anderluh G, Asadollahi M, Askin M, Barry K, Battaglia E, Bayram Ö, Benocci T, Braus-Stromeyer SA, Caldana C, Cánovas D, Cerqueira GC, Chen F, Chen W, Choi C, Clum A, dos Santos RAC, Damásio ARDL, Diallinas G, Emri T, Fekete E, Flipphi M, Freyberg S, Gallo A, Gournas C, Habgood R, Hainaut M, Harispe ML, Henrissat B, Hildén KS, Hope R, Hossain A, Karabika E, Karaffa L, Karányi Z, Kraševec N, Kuo A, Kusch H, LaButti K, Lagendijk EL, Lapidus A, Levasseur A, Lindquist E, Lipzen A, Logrieco AF, MacCabe A, Mäkelä MR, Malavazi I, Melin P, Meyer V, Mielnichuk N, Miskei M, Molnár ÁP, Mulé G, Ngan CY, Orejas M, Orosz E, Ouedraogo JP, Overkamp KM, Park HS, Perrone G, Piumi F, Punt PJ, Ram AFJ, Ramón A, Rauscher S, Record E, Riaño-Pachón DM, Robert V, Röhrig J, Ruller R, Salamov A, Salih NS, Samson RA, Sándor E, Sanguinetti M, Schütze T, Sepčić K, Shelest E, Sherlock G, Sophianopoulou V, Squina FM, Sun H, Susca A, Todd RB, Tsang A, Unkles SE, van de Wiele N, van Rossen-Uffink D, Oliveira JVDC, Vesth TC, Visser J, Yu JH, Zhou M, Andersen MR, Archer DB, Baker SE, Benoit I, Brakhage AA, Braus GH, Fischer R, Frisvad JC, Goldman GH, Houbraken J, Oakley B, Pócsi I, Scazzocchio C, Seiboth B, vanKuyk PA, Wortman J, Dyer PS, Grigoriev IV. Comparative genomics reveals high biological diversity and specific adaptations in the industrially and medically important fungal genus Aspergillus. Genome Biol 2017; 18:28. [PMID: 28196534 PMCID: PMC5307856 DOI: 10.1186/s13059-017-1151-0] [Citation(s) in RCA: 320] [Impact Index Per Article: 45.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 01/10/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The fungal genus Aspergillus is of critical importance to humankind. Species include those with industrial applications, important pathogens of humans, animals and crops, a source of potent carcinogenic contaminants of food, and an important genetic model. The genome sequences of eight aspergilli have already been explored to investigate aspects of fungal biology, raising questions about evolution and specialization within this genus. RESULTS We have generated genome sequences for ten novel, highly diverse Aspergillus species and compared these in detail to sister and more distant genera. Comparative studies of key aspects of fungal biology, including primary and secondary metabolism, stress response, biomass degradation, and signal transduction, revealed both conservation and diversity among the species. Observed genomic differences were validated with experimental studies. This revealed several highlights, such as the potential for sex in asexual species, organic acid production genes being a key feature of black aspergilli, alternative approaches for degrading plant biomass, and indications for the genetic basis of stress response. A genome-wide phylogenetic analysis demonstrated in detail the relationship of the newly genome sequenced species with other aspergilli. CONCLUSIONS Many aspects of biological differences between fungal species cannot be explained by current knowledge obtained from genome sequences. The comparative genomics and experimental study, presented here, allows for the first time a genus-wide view of the biological diversity of the aspergilli and in many, but not all, cases linked genome differences to phenotype. Insights gained could be exploited for biotechnological and medical applications of fungi.
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Affiliation(s)
- Ronald P. de Vries
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Robert Riley
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Ad Wiebenga
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Guillermo Aguilar-Osorio
- Department of Food Science and Biotechnology, Faculty of Chemistry, National University of Mexico, Ciudad Universitaria, D.F. C.P. 04510 Mexico
| | - Sotiris Amillis
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15781 Athens, Greece
| | - Cristiane Akemi Uchima
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
- Present address: VTT Brasil, Alameda Inajá, 123, CEP 06460-055 Barueri, São Paulo Brazil
| | - Gregor Anderluh
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Mojtaba Asadollahi
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Marion Askin
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Present address: CSIRO Publishing, Unipark, Building 1 Level 1, 195 Wellington Road, Clayton, VIC 3168 Australia
| | - Kerrie Barry
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Evy Battaglia
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Özgür Bayram
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
- Department of Biology, Maynooth University, Maynooth, Co. Kildare Ireland
| | - Tiziano Benocci
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Susanna A. Braus-Stromeyer
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Camila Caldana
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
- Max Planck Partner Group, Brazilian Bioethanol Science and Technology Laboratory, CEP 13083-100 Campinas, Sao Paulo Brazil
| | - David Cánovas
- Department of Genetics, Faculty of Biology, University of Seville, Avda de Reina Mercedes 6, 41012 Sevilla, Spain
- Fungal Genetics and Genomics Unit, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU) Vienna, Vienna, Austria
| | | | - Fusheng Chen
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Wanping Chen
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Cindy Choi
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Alicia Clum
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Renato Augusto Corrêa dos Santos
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - André Ricardo de Lima Damásio
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, CEP 13083-862 Campinas, SP Brazil
| | - George Diallinas
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15781 Athens, Greece
| | - Tamás Emri
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Erzsébet Fekete
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Michel Flipphi
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Susanne Freyberg
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Antonia Gallo
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), via Provinciale Lecce-Monteroni, 73100 Lecce, Italy
| | - Christos Gournas
- Institute of Biosciences and Applications, Microbial Molecular Genetics Laboratory, National Center for Scientific Research, Demokritos (NCSRD), Athens, Greece
- Present address: Université Libre de Bruxelles Institute of Molecular Biology and Medicine (IBMM), Brussels, Belgium
| | - Rob Habgood
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | | | - María Laura Harispe
- Institut Pasteur de Montevideo, Unidad Mixta INIA-IPMont, Mataojo 2020, CP11400 Montevideo, Uruguay
- Present address: Instituto de Profesores Artigas, Consejo de Formación en Educación, ANEP, CP 11800, Av. del Libertador 2025, Montevideo, Uruguay
| | - Bernard Henrissat
- CNRS, Aix-Marseille Université, Marseille, France
- INRA, USC 1408 AFMB, 13288 Marseille, France
- Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Kristiina S. Hildén
- Department of Food and Environmental Sciences, University of Helsinki, Viikinkaari 9, Helsinki, Finland
| | - Ryan Hope
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Abeer Hossain
- Dutch DNA Biotech BV, Utrechtseweg 48, 3703AJ Zeist, The Netherlands
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Eugenia Karabika
- School of Biology, University of St Andrews, St Andrews, Fife KY16 9TH UK
- Present Address: Department of Chemistry, University of Ioannina, Ioannina, 45110 Greece
| | - Levente Karaffa
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Zsolt Karányi
- Department of Medicine, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4032 Debrecen, Hungary
| | - Nada Kraševec
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Alan Kuo
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Harald Kusch
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
- Department of Medical Informatics, University Medical Centre, Robert-Koch-Str.40, 37075 Göttingen, Germany
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, Göttingen, 37073 Germany
| | - Kurt LaButti
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Ellen L. Lagendijk
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Alla Lapidus
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
- Present address: Center for Algorithmic Biotechnology, St.Petersburg State University, St. Petersburg, Russia
| | - Anthony Levasseur
- INRA, Aix-Marseille Univ, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
- Present address: Aix-Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), UM63, CNRS 7278, IRD 198, INSERM U1095, IHU Méditerranée Infection, Pôle des Maladies Infectieuses, Assistance Publique-Hôpitaux de Marseille, Faculté de Médecine, 27 Bd Jean Moulin, 13005 Marseille, France
| | - Erika Lindquist
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Anna Lipzen
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Antonio F. Logrieco
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Andrew MacCabe
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Miia R. Mäkelä
- Department of Food and Environmental Sciences, University of Helsinki, Viikinkaari 9, Helsinki, Finland
| | - Iran Malavazi
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo Brazil
| | - Petter Melin
- Uppsala BioCenter, Department of Microbiology, Swedish University of Agricultural Sciences, P.O. Box 7025, 750 07 Uppsala, Sweden
- Present address: Swedish Chemicals Agency, Box 2, 172 13 Sundbyberg, Sweden
| | - Vera Meyer
- Institute of Biotechnology, Department Applied and Molecular Microbiology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Natalia Mielnichuk
- Department of Genetics, Faculty of Biology, University of Seville, Avda de Reina Mercedes 6, 41012 Sevilla, Spain
- Present address: Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468 C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Márton Miskei
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
- MTA-DE Momentum, Laboratory of Protein Dynamics, Department of Biochemistry and Molecular Biology, University of Debrecen, Nagyerdei krt.98., 4032 Debrecen, Hungary
| | - Ákos P. Molnár
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Giuseppina Mulé
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Chew Yee Ngan
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Margarita Orejas
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Erzsébet Orosz
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Jean Paul Ouedraogo
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Present address: Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke Street West, Montreal, QC H4B 1R6 Canada
| | - Karin M. Overkamp
- Dutch DNA Biotech BV, Utrechtseweg 48, 3703AJ Zeist, The Netherlands
| | - Hee-Soo Park
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, 702-701 Republic of Korea
| | - Giancarlo Perrone
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Francois Piumi
- INRA, Aix-Marseille Univ, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
- Present address: INRA UMR1198 Biologie du Développement et de la Reproduction - Domaine de Vilvert, Jouy en Josas, 78352 Cedex France
| | - Peter J. Punt
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Dutch DNA Biotech BV, Utrechtseweg 48, 3703AJ Zeist, The Netherlands
| | - Arthur F. J. Ram
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Ana Ramón
- Sección Bioquímica, Departamento de Biología Celular y Molecular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Stefan Rauscher
- Department of Microbiology, Karlsruhe Institute of Technology, Institute for Applied Biosciences, Hertzstrasse 16,, 76187 Karlsruhe, Germany
| | - Eric Record
- INRA, Aix-Marseille Univ, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
| | - Diego Mauricio Riaño-Pachón
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - Vincent Robert
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Julian Röhrig
- Department of Microbiology, Karlsruhe Institute of Technology, Institute for Applied Biosciences, Hertzstrasse 16,, 76187 Karlsruhe, Germany
| | - Roberto Ruller
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - Asaf Salamov
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Nadhira S. Salih
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
- Department of Biology, School of Science, University of Sulaimani, Al Sulaymaneyah, Iraq
| | - Rob A. Samson
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Erzsébet Sándor
- Institute of Food Science, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, 4032 Debrecen, Hungary
| | - Manuel Sanguinetti
- Sección Bioquímica, Departamento de Biología Celular y Molecular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Tabea Schütze
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Present address: Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
| | - Ekaterina Shelest
- Systems Biology/Bioinformatics group, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
| | - Gavin Sherlock
- Department of Genetics, Stanford University, Stanford, CA 94305-5120 USA
| | - Vicky Sophianopoulou
- Institute of Biosciences and Applications, Microbial Molecular Genetics Laboratory, National Center for Scientific Research, Demokritos (NCSRD), Athens, Greece
| | - Fabio M. Squina
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - Hui Sun
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Antonia Susca
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Richard B. Todd
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506 USA
| | - Adrian Tsang
- Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke Street West, Montreal, QC H4B 1R6 Canada
| | - Shiela E. Unkles
- School of Biology, University of St Andrews, St Andrews, Fife KY16 9TH UK
| | - Nathalie van de Wiele
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Diana van Rossen-Uffink
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Present address: BaseClear B.V., Einsteinweg 5, 2333 CC Leiden, The Netherlands
| | - Juliana Velasco de Castro Oliveira
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - Tammi C. Vesth
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 223, 2800 Kongens Lyngby, Denmark
| | - Jaap Visser
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Jae-Hyuk Yu
- Departments of Bacteriology and Genetics, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706 USA
| | - Miaomiao Zhou
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Mikael R. Andersen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 223, 2800 Kongens Lyngby, Denmark
| | - David B. Archer
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Scott E. Baker
- Fungal Biotechnology Team, Pacific Northwest National Laboratory, Richland, Washington, 99352 USA
| | - Isabelle Benoit
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Present address: Centre of Functional and Structure Genomics Biology Department Concordia University, 7141 Sherbrooke St. W., Montreal, QC H4B 1R6 Canada
| | - Axel A. Brakhage
- Department of Molecular and Applied Microbiology, Leibniz-Institute for Natural Product Research and Infection Biology - Hans Knoell Institute (HKI) and Institute for Microbiology, Friedrich Schiller University Jena, Beutenbergstr. 11a, 07745 Jena, Germany
| | - Gerhard H. Braus
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Reinhard Fischer
- Department of Microbiology, Karlsruhe Institute of Technology, Institute for Applied Biosciences, Hertzstrasse 16,, 76187 Karlsruhe, Germany
| | - Jens C. Frisvad
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 223, 2800 Kongens Lyngby, Denmark
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo Brazil
| | - Jos Houbraken
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Berl Oakley
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045 USA
| | - István Pócsi
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Claudio Scazzocchio
- Department of Microbiology, Imperial College, London, SW7 2AZ UK
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, University Paris‐Sud, Université Paris‐Saclay, 91198 Gif‐sur‐Yvette cedex, France
| | - Bernhard Seiboth
- Research Division Biochemical Technology, Institute of Chemical Engineering, TU Wien, Gumpendorferstraße 1a, 1060 Vienna, Austria
| | - Patricia A. vanKuyk
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Jennifer Wortman
- Broad Institute, 415 Main St, Cambridge, MA 02142 USA
- Present address: Seres Therapeutics, 200 Sidney St, Cambridge, MA 02139 USA
| | - Paul S. Dyer
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Igor V. Grigoriev
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
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Moore GG, Mack BM, Beltz SB, Gilbert MK. Draft Genome Sequence of an Aflatoxigenic Aspergillus Species, A. bombycis. Genome Biol Evol 2016; 8:3297-3300. [PMID: 27664179 PMCID: PMC5203779 DOI: 10.1093/gbe/evw238] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2016] [Indexed: 11/18/2022] Open
Abstract
Aspergillus bombycis was first isolated from silkworm frass in Japan. It has been reportedly misidentified as A. nomius due to their macro-morphological and chemotype similarities. We sequenced the genome of the A. bombycis Type strain and found it to be comparable in size (37 Mb), as well as in numbers of predicted genes (12,266), to other sequenced Aspergilli. The aflatoxin gene cluster in this strain is similar in size and the genes are oriented the same as other B- + G-aflatoxin producing species, and this strain contains a complete but nonfunctional gene cluster for the production of cyclopiazonic acid. Our findings also showed that the A. bombycis Type strain contains a single MAT1-2 gene indicating that this species is likely heterothallic (self-infertile). This draft genome will contribute to our understanding of the genes and pathways necessary for aflatoxin synthesis as well as the evolutionary relationships of aflatoxigenic fungi.
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Affiliation(s)
- Geromy G Moore
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture
| | - Brian M Mack
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture
| | - Shannon B Beltz
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture
| | - Matthew K Gilbert
- Southern Regional Research Center, Agricultural Research Service, United States Department of Agriculture
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