1
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Han DM, Baek JH, Choi DG, Jeon MS, Eyun SI, Jeon CO. Comparative pangenome analysis of Aspergillus flavus and Aspergillus oryzae reveals their phylogenetic, genomic, and metabolic homogeneity. Food Microbiol 2024; 119:104435. [PMID: 38225047 DOI: 10.1016/j.fm.2023.104435] [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: 09/26/2023] [Revised: 11/17/2023] [Accepted: 11/25/2023] [Indexed: 01/17/2024]
Abstract
Aspergillus flavus and Aspergillus oryzae are closely related fungal species with contrasting roles in food safety and fermentation. To comprehensively investigate their phylogenetic, genomic, and metabolic characteristics, we conducted an extensive comparative pangenome analysis using complete, dereplicated genome sets for both species. Phylogenetic analyses, employing both the entirety of the identified single-copy orthologous genes and six housekeeping genes commonly used for fungal classification, did not reveal clear differentiation between A. flavus and A. oryzae genomes. Upon analyzing the aflatoxin biosynthesis gene clusters within the genomes, we observed that non-aflatoxin-producing strains were dispersed throughout the phylogenetic tree, encompassing both A. flavus and A. oryzae strains. This suggests that aflatoxin production is not a distinguishing trait between the two species. Furthermore, A. oryzae and A. flavus strains displayed remarkably similar genomic attributes, including genome sizes, gene contents, and G + C contents, as well as metabolic features and pathways. The profiles of CAZyme genes and secondary metabolite biosynthesis gene clusters within the genomes of both species further highlight their similarity. Collectively, these findings challenge the conventional differentiation of A. flavus and A. oryzae as distinct species and highlight their phylogenetic, genomic, and metabolic homogeneity, potentially indicating that they may indeed belong to the same species.
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Affiliation(s)
- Dong Min Han
- Department of Life Science, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Ju Hye Baek
- Department of Life Science, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Dae Gyu Choi
- Department of Life Science, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Min-Seung Jeon
- Department of Life Science, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Seong-Il Eyun
- Department of Life Science, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Che Ok Jeon
- Department of Life Science, Chung-Ang University, Seoul 06974, Republic of Korea.
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2
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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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3
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Steenwyk JL, Balamurugan C, Raja HA, Gonçalves C, Li N, Martin F, Berman J, Oberlies NH, Gibbons JG, Goldman GH, Geiser DM, Houbraken J, Hibbett DS, Rokas A. Phylogenomics reveals extensive misidentification of fungal strains from the genus Aspergillus. Microbiol Spectr 2024; 12:e0398023. [PMID: 38445873 PMCID: PMC10986620 DOI: 10.1128/spectrum.03980-23] [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: 11/20/2023] [Accepted: 02/18/2024] [Indexed: 03/07/2024] Open
Abstract
Modern taxonomic classification is often based on phylogenetic analyses of a few molecular markers, although single-gene studies are still common. Here, we leverage genome-scale molecular phylogenetics (phylogenomics) of species and populations to reconstruct evolutionary relationships in a dense data set of 710 fungal genomes from the biomedically and technologically important genus Aspergillus. To do so, we generated a novel set of 1,362 high-quality molecular markers specific for Aspergillus and provided profile Hidden Markov Models for each, facilitating their use by others. Examining the resulting phylogeny helped resolve ongoing taxonomic controversies, identified new ones, and revealed extensive strain misidentification (7.59% of strains were previously misidentified), underscoring the importance of population-level sampling in species classification. These findings were corroborated using the current standard, taxonomically informative loci. These findings suggest that phylogenomics of species and populations can facilitate accurate taxonomic classifications and reconstructions of the Tree of Life.IMPORTANCEIdentification of fungal species relies on the use of molecular markers. Advances in genomic technologies have made it possible to sequence the genome of any fungal strain, making it possible to use genomic data for the accurate assignment of strains to fungal species (and for the discovery of new ones). We examined the usefulness and current limitations of genomic data using a large data set of 710 publicly available genomes from multiple strains and species of the biomedically, agriculturally, and industrially important genus Aspergillus. Our evolutionary genomic analyses revealed that nearly 8% of publicly available Aspergillus genomes are misidentified. Our work highlights the usefulness of genomic data for fungal systematic biology and suggests that systematic genome sequencing of multiple strains, including reference strains (e.g., type strains), of fungal species will be required to reduce misidentification errors in public databases.
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Affiliation(s)
- Jacob L. Steenwyk
- Howards Hughes Medical Institute and the Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, USA
| | - Charu Balamurugan
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, USA
| | - Huzefa A. Raja
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina, USA
| | - Carla Gonçalves
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, USA
| | - Ningxiao Li
- Department of Plant Pathology, University of California, Davis, California, USA
- USDA-ARS, Salinas, California, USA
| | | | - Judith Berman
- Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel
| | - Nicholas H. Oberlies
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina, USA
| | - John G. Gibbons
- Department of Food Science, University of Massachusetts, Amherst, Massachusetts, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts, USA
- Organismic and Evolutionary Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts, USA
| | - Gustavo H. Goldman
- Faculdade de Ciencias Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - David M. Geiser
- Department of Plant Pathology and Environmental Microbiology, Penn State University, University Park, Pennsylvania, USA
| | - Jos Houbraken
- Food and Indoor Mycology, Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
| | - David S. Hibbett
- Biology Department, Clark University, Worcester, Massachusetts, USA
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, USA
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg, Heidelberg, Germany
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4
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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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5
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Valim HF, Grande FD, Wong ELY, Schmitt I. Circadian clock- and temperature-associated genes contribute to overall genomic differentiation along elevation in lichenized fungi. Mol Ecol 2024; 33:e17252. [PMID: 38146927 DOI: 10.1111/mec.17252] [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: 04/25/2023] [Revised: 11/24/2023] [Accepted: 12/11/2023] [Indexed: 12/27/2023]
Abstract
Circadian regulation is linked to local environmental adaptation, and many species with broad climatic niches display variation in circadian genes. Here, we hypothesize that lichenizing fungi occupying different climate zones tune their metabolism to local environmental conditions with the help of their circadian systems. We study two species of the genus Umbilicaria occupying similar climatic niches (Mediterranean and the cold temperate) in different continents. Using homology to Neurospora crassa genes, we identify gene sets associated with circadian rhythms (11 core, 39 peripheral genes) as well as temperature response (37 genes). Nucleotide diversity of these genes is significantly correlated with mean annual temperature, minimum temperature of the coldest month and mean temperature of the coldest quarter. Furthermore, we identify altitudinal clines in allele frequencies in several non-synonymous substitutions in core clock components, for example, white collar-like, frh-like and various ccg-like genes. A dN/dS approach revealed a few significant peripheral clock- and temperature-associated genes (e.g. ras-1-like, gna-1-like) that may play a role in fine-tuning the circadian clock and temperature-response machinery. An analysis of allele frequency changes demonstrated the strongest evidence for differentiation above the genomic background in the clock-associated genes in U. pustulata. These results highlight the likely relevance of the circadian clock in environmental adaptation, particularly frost tolerance, of lichens. Whether or not the fungal clock modulates the symbiotic interaction within the lichen consortium remains to be investigated. We corroborate the finding of genetic variation in clock components along altitude-not only latitude-as has been reported in other species.
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Affiliation(s)
- Henrique F Valim
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
- LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG), Frankfurt am Main, Germany
| | - Francesco Dal Grande
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
- LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG), Frankfurt am Main, Germany
- Department of Biology, University of Padova, Padua, Italy
| | - Edgar L Y Wong
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
- LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG), Frankfurt am Main, Germany
| | - Imke Schmitt
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
- LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG), Frankfurt am Main, Germany
- Institute of Ecology, Evolution and Diversity, Goethe University Frankfurt, Frankfurt am Main, Germany
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6
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Borman AM, Johnson EM. Changes in fungal taxonomy: mycological rationale and clinical implications. Clin Microbiol Rev 2023; 36:e0009922. [PMID: 37930182 PMCID: PMC10732072 DOI: 10.1128/cmr.00099-22] [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: 05/22/2023] [Accepted: 07/13/2023] [Indexed: 11/07/2023] Open
Abstract
Numerous fungal species of medical importance have been recently subjected to and will likely continue to undergo nomenclatural changes as a result of the application of molecular approaches to fungal classification together with abandonment of dual nomenclature. Here, we summarize those changes affecting key groups of fungi of medical importance, explaining the mycological (taxonomic) rationale that underpinned the changes and the clinical relevance/importance (where such exists) of the key nomenclatural revisions. Potential mechanisms to mitigate unnecessary taxonomic instability are suggested, together with approaches to raise awareness of important changes to minimize potential clinical confusion.
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Affiliation(s)
- Andrew M. Borman
- UK HSA National Mycology Reference Laboratory, Science Quarter, Southmead Hospital, Bristol, United Kingdom
- Medical Research Council Centre for Medical Mycology (MRC CMM), University of Exeter, Exeter, United Kingdom
| | - Elizabeth M. Johnson
- UK HSA National Mycology Reference Laboratory, Science Quarter, Southmead Hospital, Bristol, United Kingdom
- Medical Research Council Centre for Medical Mycology (MRC CMM), University of Exeter, Exeter, United Kingdom
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7
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Pereira DS, Hilário S, Gonçalves MFM, Phillips AJL. Diaporthe Species on Palms: Molecular Re-Assessment and Species Boundaries Delimitation in the D. arecae Species Complex. Microorganisms 2023; 11:2717. [PMID: 38004729 PMCID: PMC10673533 DOI: 10.3390/microorganisms11112717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/25/2023] [Accepted: 11/03/2023] [Indexed: 11/26/2023] Open
Abstract
Due to cryptic diversification, phenotypic plasticity and host associations, multilocus phylogenetic analyses have become the most important tool in accurately identifying and circumscribing species in the Diaporthe genus. However, the application of the genealogical concordance criterion has often been overlooked, ultimately leading to an exponential increase in novel Diaporthe spp. Due to the large number of species, many lineages remain poorly understood under the so-called species complexes. For this reason, a robust delimitation of the species boundaries in Diaporthe is still an ongoing challenge. Therefore, the present study aimed to resolve the species boundaries of the Diaporthe arecae species complex (DASC) by implementing an integrative taxonomic approach. The Genealogical Phylogenetic Species Recognition (GCPSR) principle revealed incongruences between the individual gene genealogies. Moreover, the Poisson Tree Processes' (PTPs) coalescent-based species delimitation models identified three well-delimited subclades represented by the species D. arecae, D. chiangmaiensis and D. smilacicola. These results evidence that all species previously described in the D. arecae subclade are conspecific, which is coherent with the morphological indistinctiveness observed and the absence of reproductive isolation and barriers to gene flow. Thus, 52 Diaporthe spp. are reduced to synonymy under D. arecae. Recent population expansion and the possibility of incomplete lineage sorting suggested that the D. arecae subclade may be considered as ongoing evolving lineages under active divergence and speciation. Hence, the genetic diversity and intraspecific variability of D. arecae in the context of current global climate change and the role of D. arecae as a pathogen on palm trees and other hosts are also discussed. This study illustrates that species in Diaporthe are highly overestimated, and highlights the relevance of applying an integrative taxonomic approach to accurately circumscribe the species boundaries in the genus Diaporthe.
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Affiliation(s)
- Diana S. Pereira
- Faculdade de Ciências, Biosystems and Integrative Sciences Institute (BioISI), Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal;
| | - Sandra Hilário
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Porto, Portugal;
- Faculty of Sciences, Biology Department, University of Porto, Rua do Campo Alegre, Edifício FC4, 4169-007 Porto, Portugal
| | - Micael F. M. Gonçalves
- Faculty of Sciences, Biology Department, University of Porto, Rua do Campo Alegre, Edifício FC4, 4169-007 Porto, Portugal
- Centre for Environmental and Marine Studies, Department of Biology, Campus Universitário de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Alan J. L. Phillips
- Faculdade de Ciências, Biosystems and Integrative Sciences Institute (BioISI), Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal;
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Chen Y, Han A, Wang M, Wei D, Wang W. Metabolic Engineering of Trichoderma reesei for l-Malic Acid Production. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:4043-4050. [PMID: 36812909 DOI: 10.1021/acs.jafc.2c09078] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
l-Malic acid has various applications in the chemical and food industries. The filamentous fungus Trichoderma reesei is known to be an efficient enzyme producer. Here, through metabolic engineering, T. reesei was constructed for the first time as an excellent cell factory for l-malic acid production. The heterologous overexpression of genes encoding the C4-dicarboxylate transporter from Aspergillus oryzae and Schizosaccharomyces pombe initiated l-malic acid production. The overexpression of pyruvate carboxylase from A. oryzae in the reductive tricarboxylic acid pathway further increased both the titer and yield of l-malic acid, resulting in the highest titer reported in a shake-flask culture. Furthermore, the deletion of malate thiokinase blocked l-malic acid degradation. Finally, the engineered T. reesei strain produced 220.5 g/L of l-malic acid in a 5 L fed-batch culture (productivity of 1.15 g/L/h). A T. reesei cell factory was created for the efficient production of l-malic acid.
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Affiliation(s)
- Yumeng Chen
- State Key Lab of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Ao Han
- State Key Lab of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Meng Wang
- State Key Lab of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Dongzhi Wei
- State Key Lab of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Wei Wang
- State Key Lab of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
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9
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Ge YD, Guo YT, Jiang LL, Wang HH, Hou SL, Su FZ. Enzymatic Characterization and Coenzyme Specificity Conversion of a Novel Dimeric Malate Dehydrogenase from Bacillus subtilis. Protein J 2023; 42:14-23. [PMID: 36534341 PMCID: PMC9761052 DOI: 10.1007/s10930-022-10087-0] [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] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Malate is an important material to various industrials and clinical applications. Bacillus subtilis is a widely used biocatalyst tool for chemical production. However, the specific enzymatic properties of malate dehydrogenase from Bacillus subtilis (BsMDH) remain largely unknown. In the present study, BsMDH was cloned, recombinantly expressed and purified to test its enzymatic properties. The molecular weight of single unit of BsMDH was 34,869.7 Da. Matrix-Assisted Laser-Desorption Ionization-Time-of-Flight Mass Spectrometry and gel filtration analysis indicated that the recombinant BsMDH could form dimers. The kcat/Km values of oxaloacetate and NADH were higher than those of malate and NAD+, respectively, indicating a better catalysis in the direction of malate synthesis than the reverse. Furthermore, six BsMDH mutants were constructed with the substitution of amino acids at the coenzyme binding site. Among them, BsMDH-T7 showed a greatly higher affinity and catalysis efficiency to NADPH than NADH with the degree of alteration of 2039, suggesting the shift of the coenzyme dependence from NADH to NADPH. In addition, BsMDH-T7 showed a relatively lower Km value, but a higher kcat and kcat/Km than NADPH-dependent MDHs from Thermus flavus and Corynebacterium glutamicum. Overall, these results indicated that BsMDH and BsMDH-T7 mutant might be promising enzymes for malate production.
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Affiliation(s)
- Ya-Dong Ge
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, People's Republic of China.
| | - Yi-Tian Guo
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, People's Republic of China
| | - Lu-Lu Jiang
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, People's Republic of China
| | - Hui-Hui Wang
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, People's Republic of China
| | - Shao-Lin Hou
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, People's Republic of China
| | - Feng-Zhi Su
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, People's Republic of China
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Deep Genotypic Species Delimitation of Aspergillus Section Flavi Isolated from Brazilian Foodstuffs and the Description of Aspergillus annui sp. nov. and Aspergillus saccharicola sp. nov. J Fungi (Basel) 2022; 8:jof8121279. [PMID: 36547612 PMCID: PMC9781283 DOI: 10.3390/jof8121279] [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: 10/20/2022] [Revised: 11/25/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
Aspergillus section Flavi is a fungal group that is important in food because it contains spoilage and potentially aflatoxigenic species. Aflatoxins are metabolites that are harmful to human and animal health and have been recognized as the primary natural contaminant in food. Therefore, recognizing the biodiversity of this group in food is necessary to reduce risks to public health. Our study aimed to investigate the diversity of Aspergillus section Flavi isolated from Brazilian foodstuffs such as cassava, sugarcane, black pepper, paprika, Brazil nuts, yerba-mate, peanuts, rice, and corn. A polyphasic approach integrating phenotypic data and multilocus genotypic analyses (CaM, BenA, and RPB2) was performed for 396 strains. Two new species in the Aspergillus subgenus Circumdati section Flavi are proposed using maximum-likelihood analysis, Bayesian inference, and coalescence-based methods: Aspergillus saccharicola sp. nov. and Aspergillus annui sp. nov. A. saccharicola sp. nov. belongs to the series Flavi, is a potentially aflatoxigenic species (B1, B2, G1, and G2), closely related to Aspergillus arachidicola, and was found mostly in sugarcane. A. annui sp. nov. was isolated from samples of sweet paprika. To accommodate A. annui sp. nov., a new series Annuorum was proposed.
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11
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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: 0] [Impact Index Per Article: 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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12
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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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13
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Yadav M, Sehrawat N, Kumar S, Sharma AK, Singh M, Kumar A. Malic acid: fermentative production and applications. PHYSICAL SCIENCES REVIEWS 2022. [DOI: 10.1515/psr-2022-0165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Microbial metabolites have gained lot of industrial interest. These are currently employed in various industries including pharmaceuticals, chemical, textiles, food etc. Organic acids are among the important microbial products. Production of microbial organic acids present numerous advantages like agro-industrial waste may be utilized as substrate, low production cost, natural in origin and production is environment friendly. Malic acid is an organic acid (C4 dicarboxylic acid) that can be produced by microbes. It is also useful in industrial sectors as food, chemicals, and pharmaceuticals etc. Production/extraction of malic acid has been reported from fruits, egg shells, microbes, via chemical synthesis, bio-transformation and from renewable sources. Microbial production of malic acid seems very promising due to various advantages and the approach is environment-friendly. In recent years, researchers have focused on fermentative microbial production of malic acid and possibility of using agro-industrial waste as raw substrates. In current article, malic acid production along with applications has been discussed with recent advances in the area.
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Affiliation(s)
- Mukesh Yadav
- Department of Biotechnology , Maharishi Markandeshwar (Deemed to be University) , Mullana-Ambala , India
| | - Nirmala Sehrawat
- Department of Biotechnology , Maharishi Markandeshwar (Deemed to be University) , Mullana-Ambala , India
| | - Sunil Kumar
- Department of Microbiology, Faculty of Bio-Medical Sciences , Kampala International University , Kampala , Uganda
| | - Anil Kumar Sharma
- Department of Biotechnology , Maharishi Markandeshwar (Deemed to be University) , Mullana-Ambala , India
| | - Manoj Singh
- Department of Biotechnology , Maharishi Markandeshwar (Deemed to be University) , Mullana-Ambala , India
| | - Amit Kumar
- Department of Biotechnology, School of Engineering and Technology , Sharda University , Greater Noida , U.P. , India
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14
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Recombination-aware phylogeographic inference using the structured coalescent with ancestral recombination. PLoS Comput Biol 2022; 18:e1010422. [PMID: 35984849 PMCID: PMC9447913 DOI: 10.1371/journal.pcbi.1010422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 09/06/2022] [Accepted: 07/21/2022] [Indexed: 11/19/2022] Open
Abstract
Movement of individuals between populations or demes is often restricted, especially between geographically isolated populations. The structured coalescent provides an elegant theoretical framework for describing how movement between populations shapes the genealogical history of sampled individuals and thereby structures genetic variation within and between populations. However, in the presence of recombination an individual may inherit different regions of their genome from different parents, resulting in a mosaic of genealogical histories across the genome, which can be represented by an Ancestral Recombination Graph (ARG). In this case, different genomic regions may have different ancestral histories and so different histories of movement between populations. Recombination therefore poses an additional challenge to phylogeographic methods that aim to reconstruct the movement of individuals from genealogies, although also a potential benefit in that different loci may contain additional information about movement. Here, we introduce the Structured Coalescent with Ancestral Recombination (SCAR) model, which builds on recent approximations to the structured coalescent by incorporating recombination into the ancestry of sampled individuals. The SCAR model allows us to infer how the migration history of sampled individuals varies across the genome from ARGs, and improves estimation of key population genetic parameters such as population sizes, recombination rates and migration rates. Using the SCAR model, we explore the potential and limitations of phylogeographic inference using full ARGs. We then apply the SCAR to lineages of the recombining fungus Aspergillus flavus sampled across the United States to explore patterns of recombination and migration across the genome. Phylogeographic methods are widely used to reconstruct the historical movement of individuals between different populations. When applied to infectious pathogens, these methods are often used to reconstruct the origin or source of novel pathogen lineages. Most existing phylogeographic methods reconstruct movement based on a single phylogenetic tree, which is assumed to reflect the genetic ancestry of all sampled individuals. However in populations undergoing recombination, genetic material can be exchanged between lineages such that individuals may inherit different regions of their genome from different ancestors. In this case, phylogenetic relationships among individuals can only be captured by a reticulated network rather than any single tree. Ancestral Recombination Graphs (ARGs) provide one way of capturing these reticulate relationships and we develop new models that allow for demographic inference of historical population sizes, recombination rates and migration rates between subpopulations from ARGs. By accounting for recombination, our models not only allow for accurate demographic inference, but can take full advantage of the additional information contained in ARGs about how ancestry varies across genomes to more precisely reconstruct the movement of genetic material between populations.
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15
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Aspergillus flavus and Total Aflatoxins Occurrence in Dairy Feed and Aflatoxin M1 in Bovine Milk in Aguascalientes, Mexico. Toxins (Basel) 2022; 14:toxins14050292. [PMID: 35622539 PMCID: PMC9143994 DOI: 10.3390/toxins14050292] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/09/2022] [Accepted: 04/16/2022] [Indexed: 02/01/2023] Open
Abstract
Contamination of food chains by toxigenic fungi and aflatoxins is a global problem that causes damage to human health, as well as to crop and livestock production. The objective is to evaluate Aspergillus flavus and total aflatoxins (AFs) occurrence in totally mixed rations (TMRs) for dairy cows and aflatoxin M1 (AFM1) in milk for human consumption. Ninety-nine dairy production units located in Aguascalientes, Mexico, were randomly selected, and samples were collected from TMRs, raw milk, and milk marketed in the city in two consecutive agricultural cycles. AFs were quantified in TMRs and milk by indirect enzyme immunoassay and HPLC; aflatoxigenic and molecular (PCR) capacity of monosporic A. flavus isolates in the feed was characterized. All feed, raw, and pasteurized milk samples showed aflatoxin contamination (26.0 ± 0.4 µg/kg, 32.0 ± 1.0, and 31.3 ± 0.7 ng/L, respectively), and a significant proportion (90.4, 11.3, and 10.3%) exceeded the locally applied maximum permissible limits for feed and milk (20.0 µg/kg and 50 ng/L). Aflatoxin contamination in both TMRs and milk indicated a seasonal influence, with a higher concentration in the autumn–winter cycle when conditions of higher humidity prevail. The results obtained suggest the existence of contamination by aflatoxigenic A. flavus and aflatoxins in the diet formulated for feeding dairy cows and, consequently, in the dairy food chain of this region of the Mexican Highland Plateau.
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16
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Silva JJ, Fungaro MHP, Soto TS, Taniwaki MH, Iamanaka BT. Low-cost, specific PCR assays to identify the main aflatoxigenic species of Aspergillus section Flavi. METHODS IN MICROBIOLOGY 2022; 196:106470. [PMID: 35447279 DOI: 10.1016/j.mimet.2022.106470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 03/26/2022] [Accepted: 04/12/2022] [Indexed: 01/10/2023]
Abstract
Aflatoxins are fungal metabolites that are present as contaminants in food globally. Most aflatoxigenic species belong to Aspergillus section Flavi, and the main ones are grouped in the A. flavus clade, where many cryptic species that are difficult to discriminate are found. In this study, we investigated inter- and intraspecific diversity of the A. flavus clade to develop low-cost, species-specific PCR assays for identifying aflatoxigenic species. A total of 269 sequences of the second largest subunit of RNA polymerase II (RPB2) locus were retrieved from GenBank, and primer pairs were designed using data mining to identify A. flavus, A. parasiticus, and A. novoparasiticus. Species-specific amplicons of approximately 620, 350, and 860 bp enabled identification of target species as A. flavus, A. parasiticus, and A. novoparasiticus, respectively.
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Affiliation(s)
- Josué J Silva
- Institute of Food Technology - ITAL, Campinas, SP, Brazil.
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17
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Abstract
Alternaria alternata is a common species of fungus frequently isolated from plants as both an endophyte and a pathogen. Although the current definition of A. alternata rests on a foundation of morphological, genetic and genomic analyses, doubts persist regarding the scope of A. alternata within the genus due to the varied symbiotic interactions and wide host range observed in these fungi. These doubts may be due in large part to the history of unstable taxonomy in Alternaria, based on limited morphological characters for species delimitation and host specificity associated with toxins encoded by genes carried on conditionally dispensable chromosomes. This review explores the history of Alternaria taxonomy, focusing in particular on the use of nutritional mode and host associations in species delimitation, with the goal of evaluating A. alternata as it currently stands based on taxonomic best practice. Given the recombination detected among isolates of A. alternata, different symbiotic associations in this species should not be considered phylogenetically informative.
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Affiliation(s)
- Mara DeMers
- Plant and Microbial Biology Department, College of Biological Sciences, University of Minnesota, St. Paul, MN, USA
- *Correspondence: Mara DeMers,
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18
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Sweany RR, Mack BM, Moore GG, Gilbert MK, Cary JW, Lebar MD, Rajasekaran K, Damann Jr. KE. Genetic Responses and Aflatoxin Inhibition during Co-Culture of Aflatoxigenic and Non-Aflatoxigenic Aspergillus flavus. Toxins (Basel) 2021; 13:794. [PMID: 34822579 PMCID: PMC8618995 DOI: 10.3390/toxins13110794] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/30/2021] [Accepted: 11/05/2021] [Indexed: 11/16/2022] Open
Abstract
Aflatoxin is a carcinogenic mycotoxin produced by Aspergillus flavus. Non-aflatoxigenic (Non-tox) A. flavus isolates are deployed in corn fields as biocontrol because they substantially reduce aflatoxin contamination via direct replacement and additionally via direct contact or touch with toxigenic (Tox) isolates and secretion of inhibitory/degradative chemicals. To understand touch inhibition, HPLC analysis and RNA sequencing examined aflatoxin production and gene expression of Non-tox isolate 17 and Tox isolate 53 mono-cultures and during their interaction in co-culture. Aflatoxin production was reduced by 99.7% in 72 h co-cultures. Fewer than expected unique reads were assigned to Tox 53 during co-culture, indicating its growth and/or gene expression was inhibited in response to Non-tox 17. Predicted secreted proteins and genes involved in oxidation/reduction were enriched in Non-tox 17 and co-cultures compared to Tox 53. Five secondary metabolite (SM) gene clusters and kojic acid synthesis genes were upregulated in Non-tox 17 compared to Tox 53 and a few were further upregulated in co-cultures in response to touch. These results suggest Non-tox strains can inhibit growth and aflatoxin gene cluster expression in Tox strains through touch. Additionally, upregulation of other SM genes and redox genes during the biocontrol interaction demonstrates a potential role of inhibitory SMs and antioxidants as additional biocontrol mechanisms and deserves further exploration to improve biocontrol formulations.
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Affiliation(s)
- Rebecca R. Sweany
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Brian M. Mack
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Geromy G. Moore
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Matthew K. Gilbert
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Jeffrey W. Cary
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Matthew D. Lebar
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Kanniah Rajasekaran
- Food and Feed Safety Research Unit, Southern Regional Research Center, US Department of Agriculture, New Orleans, LA 70124, USA; (B.M.M.); (M.K.G.); (J.W.C.); (M.D.L.)
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
| | - Kenneth E. Damann Jr.
- Department of Plant Pathology and Crop Physiology, Louisiana State University, Baton Rouge, LA 70808, USA;
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19
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Wei Z, Xu Y, Xu Q, Cao W, Huang H, Liu H. Microbial Biosynthesis of L-Malic Acid and Related Metabolic Engineering Strategies: Advances and Prospects. Front Bioeng Biotechnol 2021; 9:765685. [PMID: 34660563 PMCID: PMC8511312 DOI: 10.3389/fbioe.2021.765685] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 09/16/2021] [Indexed: 11/13/2022] Open
Abstract
Malic acid, a four-carbon dicarboxylic acid, is widely used in the food, chemical and medical industries. As an intermediate of the TCA cycle, malic acid is one of the most promising building block chemicals that can be produced from renewable sources. To date, chemical synthesis or enzymatic conversion of petrochemical feedstocks are still the dominant mode for malic acid production. However, with increasing concerns surrounding environmental issues in recent years, microbial fermentation for the production of L-malic acid was extensively explored as an eco-friendly production process. The rapid development of genetic engineering has resulted in some promising strains suitable for large-scale bio-based production of malic acid. This review offers a comprehensive overview of the most recent developments, including a spectrum of wild-type, mutant, laboratory-evolved and metabolically engineered microorganisms for malic acid production. The technological progress in the fermentative production of malic acid is presented. Metabolic engineering strategies for malic acid production in various microorganisms are particularly reviewed. Biosynthetic pathways, transport of malic acid, elimination of byproducts and enhancement of metabolic fluxes are discussed and compared as strategies for improving malic acid production, thus providing insights into the current state of malic acid production, as well as further research directions for more efficient and economical microbial malic acid production.
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Affiliation(s)
- Zhen Wei
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, China
| | - Yongxue Xu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, China
| | - Qing Xu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Wei Cao
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, China.,Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, Tianjin, China
| | - He Huang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Hao Liu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, China.,Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, Tianjin, China
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20
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Chacón-Vargas K, McCarthy CO, Choi D, Wang L, Yu JH, Gibbons JG. Comparison of Two Aspergillus oryzae Genomes From Different Clades Reveals Independent Evolution of Alpha-Amylase Duplication, Variation in Secondary Metabolism Genes, and Differences in Primary Metabolism. Front Microbiol 2021; 12:691296. [PMID: 34326825 PMCID: PMC8313989 DOI: 10.3389/fmicb.2021.691296] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/22/2021] [Indexed: 12/02/2022] Open
Abstract
Microbes (bacteria, yeasts, molds), in addition to plants and animals, were domesticated for their roles in food preservation, nutrition and flavor. Aspergillus oryzae is a domesticated filamentous fungal species traditionally used during fermentation of Asian foods and beverage, such as sake, soy sauce, and miso. To date, little is known about the extent of genome and phenotypic variation of A. oryzae isolates from different clades. Here, we used long-read Oxford Nanopore and short-read Illumina sequencing to produce a highly accurate and contiguous genome assemble of A. oryzae 14160, an industrial strain from China. To understand the relationship of this isolate, we performed phylogenetic analysis with 90 A. oryzae isolates and 1 isolate of the A. oryzae progenitor, Aspergillus flavus. This analysis showed that A. oryzae 14160 is a member of clade A, in comparison to the RIB 40 type strain, which is a member of clade F. To explore genome variation between isolates from distinct A. oryzae clades, we compared the A. oryzae 14160 genome with the complete RIB 40 genome. Our results provide evidence of independent evolution of the alpha-amylase gene duplication, which is one of the major adaptive mutations resulting from domestication. Synteny analysis revealed that both genomes have three copies of the alpha-amylase gene, but only one copy on chromosome 2 was conserved. While the RIB 40 genome had additional copies of the alpha-amylase gene on chromosomes III, and V, 14160 had a second copy on chromosome II and an third copy on chromosome VI. Additionally, we identified hundreds of lineage specific genes, and putative high impact mutations in genes involved in secondary metabolism, including several of the core biosynthetic genes. Finally, to examine the functional effects of genome variation between strains, we measured amylase activity, proteolytic activity, and growth rate on several different substrates. RIB 40 produced significantly higher levels of amylase compared to 14160 when grown on rice and starch. Accordingly, RIB 40 grew faster on rice, while 14160 grew faster on soy. Taken together, our analyses reveal substantial genome and phenotypic variation within A. oryzae.
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Affiliation(s)
- Katherine Chacón-Vargas
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA, United States.,Department of Food Science, University of Massachusetts, Amherst, MA, United States
| | - Colin O McCarthy
- Department of Food Science, University of Massachusetts, Amherst, MA, United States
| | - Dasol Choi
- Deapertment of Food Science, University of Wisconsin-Madison, Madison, WI, United States.,Department of Bacteriology, and Food Research Institute, University of Wisconsin-Madison, Madison, WI, United States
| | - Long Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jae-Hyuk Yu
- Department of Bacteriology, and Food Research Institute, University of Wisconsin-Madison, Madison, WI, United States.,Department of Systems Biotechnology, Konkuk University, Seoul, South Korea
| | - John G Gibbons
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA, United States.,Department of Food Science, University of Massachusetts, Amherst, MA, United States.,Organismic & Evolutionary Biology Graduate Program, University of Massachusetts, Amherst, MA, United States
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21
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Daba GM, Mostafa FA, Elkhateeb WA. The ancient koji mold (Aspergillus oryzae) as a modern biotechnological tool. BIORESOUR BIOPROCESS 2021; 8:52. [PMID: 38650252 PMCID: PMC10992763 DOI: 10.1186/s40643-021-00408-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 06/16/2021] [Indexed: 01/07/2023] Open
Abstract
Aspergillus oryzae (A. oryzae) is a filamentous micro-fungus that is used from centuries in fermentation of different foods in many countries all over the world. This valuable fungus is also a rich source of many bioactive secondary metabolites. Moreover, A. oryzae has a prestigious secretory system that allows it to secrete high concentrations of proteins into its culturing medium, which support its use as biotechnological tool in veterinary, food, pharmaceutical, and industrial fields. This review aims to highlight the significance of this valuable fungus in food industry, showing its generosity in production of nutritional and bioactive metabolites that enrich food fermented by it. Also, using A. oryzae as a biotechnological tool in the field of enzymes production was described. Furthermore, domestication, functional genomics, and contributions of A. oryzae in functional production of human pharmaceutical proteins were presented. Finally, future prospects in order to get more benefits from A. oryzae were discussed.
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Affiliation(s)
- Ghoson M Daba
- Chemistry of Natural and Microbial Products Department, Pharmaceutical Industries Researches Division, National Research Centre, El Buhouth Street, Dokki, Giza, 12311, Egypt.
| | - Faten A Mostafa
- Chemistry of Natural and Microbial Products Department, Pharmaceutical Industries Researches Division, National Research Centre, El Buhouth Street, Dokki, Giza, 12311, Egypt.
| | - Waill A Elkhateeb
- Chemistry of Natural and Microbial Products Department, Pharmaceutical Industries Researches Division, National Research Centre, El Buhouth Street, Dokki, Giza, 12311, Egypt
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22
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Pickova D, Ostry V, Toman J, Malir F. Aflatoxins: History, Significant Milestones, Recent Data on Their Toxicity and Ways to Mitigation. Toxins (Basel) 2021; 13:399. [PMID: 34205163 PMCID: PMC8227755 DOI: 10.3390/toxins13060399] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/04/2021] [Accepted: 06/02/2021] [Indexed: 02/07/2023] Open
Abstract
In the early 1960s the discovery of aflatoxins began when a total of 100,000 turkey poults died by hitherto unknown turkey "X" disease in England. The disease was associated with Brazilian groundnut meal affected by Aspergillus flavus. The toxin was named Aspergillus flavus toxin-aflatoxin. From the point of view of agriculture, aflatoxins show the utmost importance. Until now, a total of 20 aflatoxins have been described, with B1, B2, G1, and G2 aflatoxins being the most significant. Contamination by aflatoxins is a global health problem. Aflatoxins pose acutely toxic, teratogenic, immunosuppressive, carcinogenic, and teratogenic effects. Besides food insecurity and human health, aflatoxins affect humanity at different levels, such as social, economical, and political. Great emphasis is placed on aflatoxin mitigation using biocontrol methods. Thus, this review is focused on aflatoxins in terms of historical development, the principal milestones of aflatoxin research, and recent data on their toxicity and different ways of mitigation.
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Affiliation(s)
- Darina Pickova
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (J.T.); (F.M.)
| | - Vladimir Ostry
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (J.T.); (F.M.)
- Center for Health, Nutrition and Food in Brno, National Institute of Public Health in Prague, Palackeho 3a, CZ-61242 Brno, Czech Republic
| | - Jakub Toman
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (J.T.); (F.M.)
| | - Frantisek Malir
- Department of Biology, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, CZ-50003 Hradec Kralove, Czech Republic; (V.O.); (J.T.); (F.M.)
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23
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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: 22] [Impact Index Per Article: 7.3] [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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24
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Osman M, Bidon B, Abboud C, Zakaria A, Hamze B, Achcar ME, Mallat H, Dannaoui E, Dabboussi F, Papon N, Bouchara JP, Hamze M. Species distribution and antifungal susceptibility of Aspergillus clinical isolates in Lebanon. Future Microbiol 2021; 16:13-26. [PMID: 33438473 DOI: 10.2217/fmb-2020-0141] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Aim: We sought to provide first insights into the epidemiology and antifungal susceptibility patterns of the aspergilli in Lebanon. Materials & methods: After species identification, antifungal susceptibility was investigated according to EUCAST recommendations. CYP51A gene was sequenced in resistant isolates and its expression level was evaluated by Reverse transcription-quantitative PCR. Results: Among the 73 Aspergillus isolates studied (mostly from ears), the predominant species was Aspergillus niger (54.8%). The overall drug resistance was highest for amphotericin B (38.4%), followed by itraconazole (31.5%), posaconazole (30.1%) and voriconazole (23.3%). In addition, CYP51A gene mutations were not the major cause of azole resistance among these isolates. Conclusion: Our findings indicate the paramount need for an integral One Health strategy and a national reference center for invasive mycoses and antifungals.
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Affiliation(s)
- Marwan Osman
- Laboratoire Microbiologie Santé et Environnement (LMSE), Doctoral School of Science & Technology, Faculty of Public Health, Lebanese University, Tripoli, Lebanon
| | - Baptiste Bidon
- Groupe d'Etude des Interactions Hôte-Pathogène, GEIHP, EA3142, SFR 4208 ICAT, Univ Angers, Univ Brest, Angers, France
| | - Cynthia Abboud
- Laboratoire Microbiologie Santé et Environnement (LMSE), Doctoral School of Science & Technology, Faculty of Public Health, Lebanese University, Tripoli, Lebanon.,Groupe d'Etude des Interactions Hôte-Pathogène, GEIHP, EA3142, SFR 4208 ICAT, Univ Angers, Univ Brest, Angers, France
| | - Ayate Zakaria
- Laboratoire Microbiologie Santé et Environnement (LMSE), Doctoral School of Science & Technology, Faculty of Public Health, Lebanese University, Tripoli, Lebanon
| | - Baraa Hamze
- Laboratoire Microbiologie Santé et Environnement (LMSE), Doctoral School of Science & Technology, Faculty of Public Health, Lebanese University, Tripoli, Lebanon
| | | | - Hassan Mallat
- Laboratoire Microbiologie Santé et Environnement (LMSE), Doctoral School of Science & Technology, Faculty of Public Health, Lebanese University, Tripoli, Lebanon
| | - Eric Dannaoui
- Paris-Descartes University, Faculty of Medicine, APHP, European Georges Pompidou Hospital, Parasitology-Mycology Unit, Microbiology department, Paris, France
| | - Fouad Dabboussi
- Laboratoire Microbiologie Santé et Environnement (LMSE), Doctoral School of Science & Technology, Faculty of Public Health, Lebanese University, Tripoli, Lebanon
| | - Nicolas Papon
- Groupe d'Etude des Interactions Hôte-Pathogène, GEIHP, EA3142, SFR 4208 ICAT, Univ Angers, Univ Brest, Angers, France
| | - Jean-Philippe Bouchara
- Groupe d'Etude des Interactions Hôte-Pathogène, GEIHP, EA3142, SFR 4208 ICAT, Univ Angers, Univ Brest, Angers, France
| | - Monzer Hamze
- Laboratoire Microbiologie Santé et Environnement (LMSE), Doctoral School of Science & Technology, Faculty of Public Health, Lebanese University, Tripoli, Lebanon
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Two New Aspergillus flavus Reference Genomes Reveal a Large Insertion Potentially Contributing to Isolate Stress Tolerance and Aflatoxin Production. G3-GENES GENOMES GENETICS 2020; 10:3515-3531. [PMID: 32817124 PMCID: PMC7534430 DOI: 10.1534/g3.120.401405] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Efforts in genome sequencing in the Aspergillus genus have led to the development of quality reference genomes for several important species including A. nidulans, A. fumigatus, and A. oryzae However, less progress has been made for A. flavus As part of the effort of the USDA-ARS Annual Aflatoxin Workshop Fungal Genome Project, the isolate NRRL3357 was sequenced and resulted in a scaffold-level genome released in 2005. Our goal has been biologically driven, focusing on two areas: isolate variation in aflatoxin production and drought stress exacerbating aflatoxin production by A. flavus Therefore, we developed two reference pseudomolecule genome assemblies derived from chromosome arms for two isolates: AF13, a MAT1-2, highly stress tolerant, and highly aflatoxigenic isolate; and NRRL3357, a MAT1-1, less stress tolerant, and moderate aflatoxin producer in comparison to AF13. Here, we report these two reference-grade assemblies for these isolates through a combination of PacBio long-read sequencing and optical mapping, and coupled them with comparative, functional, and phylogenetic analyses. This analysis resulted in the identification of 153 and 45 unique genes in AF13 and NRRL3357, respectively. We also confirmed the presence of a unique 310 Kb insertion in AF13 containing 60 genes. Analysis of this insertion revealed the presence of a bZIP transcription factor, named atfC, which may contribute to isolate pathogenicity and stress tolerance. Phylogenomic analyses comparing these and other available assemblies also suggest that the species complex of A. flavus is polyphyletic.
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Xue L, Zhang Y, Duan T, Li M, White JF, Liu Y, Li C. Characterization and Pathogenicity of Colletotrichum Species on Philodendron tatei cv. Congo in Gansu Province, China. PLANT DISEASE 2020; 104:2571-2584. [PMID: 32816625 DOI: 10.1094/pdis-09-19-1952-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In recent years in China, leaf spot caused by Colletotrichum species has been an emerging disease of Philodendron tatei cv. Congo. From 2016 to 2019, typical symptoms, appearing as circular or ovoid, sunken, and brown lesions with a yellow halo, were commonly observed on P. tatei cv. Congo in and around Lanzhou, Gansu Province, China. Conidiomata were often visible on infected leaf surfaces. Leaf disease incidence was approximately 5 to 20%. A total of 126 single-spored Colletotrichum isolates were obtained from leaf lesions. Multilocus phylogenetic relationships were analyzed based on seven genomic loci (ITS, ACT, GAPDH, HIS3, CAL, CHS-1, and TUB2) and the morphological characters of the isolates determined. These isolates were identified as three Colletotrichum species in this study. A further 93 isolates, accounting for 74% of all Colletotrichum isolates, were described as new species and named as Colletotrichum philodendricola sp. nov. after the host plant genus name, Philodendron; another two isolates were named as C. pseudoboninense sp. nov. based on phylogenetic and morphological relativeness to C. boninense; the other 31 isolates, belonging to the C. orchidearum species complex, were identified as a known species-C. orchidearum. Both novel species C. philodendricola and C. pseudoboninense belong to the C. boninense species complex. Pathogenicity tests by both spray and point inoculations confirmed that all three species could infect leaves of P. tatei cv. Congo. For spray inoculation, the mean infection rate of leaves on the three species was only 4.7% (0 to 12%), and the size on lesions was mostly 1 to 2 mm in length. For point inoculation, 30 days after nonwounding inoculation, the infection rate on leaves was 0 to 35%; in wounding inoculation, the infection rate of leaves was 35 to 65%; wounding in healthy leaves greatly enhanced the pathogenicity of these three species to P. tatei cv. Congo; however, the sizes of lesions among the three species were not significantly different. To our knowledge, this is the first report of Colletotrichum species associated with anthracnose diseases on P. tatei cv. Congo. Results obtained in this study will assist the disease prevention and appropriate management strategies.
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Affiliation(s)
- Longhai Xue
- State Key Laboratory of Grassland Agro-Ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry, Ministry of Education; Gansu Tech Innovation Center of Western China Grassland Industry; Center for Grassland Microbiome; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
- Institute of Plant Protection, Sichuan Academy of Agricultural Sciences, Chengdu 610066, China
| | - Yongwen Zhang
- State Key Laboratory of Grassland Agro-Ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry, Ministry of Education; Gansu Tech Innovation Center of Western China Grassland Industry; Center for Grassland Microbiome; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
| | - Tingyu Duan
- State Key Laboratory of Grassland Agro-Ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry, Ministry of Education; Gansu Tech Innovation Center of Western China Grassland Industry; Center for Grassland Microbiome; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
| | - Mengyuan Li
- College of Management, Lanzhou University, Lanzhou 730020, China
| | - James F White
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901-8520, U.S.A
| | - Yong Liu
- Institute of Plant Protection, Sichuan Academy of Agricultural Sciences, Chengdu 610066, China
| | - Chunjie Li
- State Key Laboratory of Grassland Agro-Ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry, Ministry of Education; Gansu Tech Innovation Center of Western China Grassland Industry; Center for Grassland Microbiome; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
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27
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Drott MT, Satterlee TR, Skerker JM, Pfannenstiel BT, Glass NL, Keller NP, Milgroom MG. The Frequency of Sex: Population Genomics Reveals Differences in Recombination and Population Structure of the Aflatoxin-Producing Fungus Aspergillus flavus. mBio 2020; 11:e00963-20. [PMID: 32665272 PMCID: PMC7360929 DOI: 10.1128/mbio.00963-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/18/2020] [Indexed: 11/20/2022] Open
Abstract
The apparent rarity of sex in many fungal species has raised questions about how much sex is needed to purge deleterious mutations and how differences in frequency of sex impact fungal evolution. We sought to determine how differences in the extent of recombination between populations of Aspergillus flavus impact the evolution of genes associated with the synthesis of aflatoxin, a notoriously potent carcinogen. We sequenced the genomes of, and quantified aflatoxin production in, 94 isolates of A. flavus sampled from seven states in eastern and central latitudinal transects of the United States. The overall population is subdivided into three genetically differentiated populations (A, B, and C) that differ greatly in their extent of recombination, diversity, and aflatoxin-producing ability. Estimates of the number of recombination events and linkage disequilibrium decay suggest relatively frequent sex only in population A. Population B is sympatric with population A but produces significantly less aflatoxin and is the only population where the inability of nonaflatoxigenic isolates to produce aflatoxin was explained by multiple gene deletions. Population expansion evident in population B suggests a recent introduction or range expansion. Population C is largely nonaflatoxigenic and restricted mainly to northern sampling locations through restricted migration and/or selection. Despite differences in the number and type of mutations in the aflatoxin gene cluster, codon optimization and site frequency differences in synonymous and nonsynonymous mutations suggest that low levels of recombination in some A. flavus populations are sufficient to purge deleterious mutations.IMPORTANCE Differences in the relative frequencies of sexual and asexual reproduction have profound implications for the accumulation of deleterious mutations (Muller's ratchet), but little is known about how these differences impact the evolution of ecologically important phenotypes. Aspergillus flavus is the main producer of aflatoxin, a notoriously potent carcinogen that often contaminates food. We investigated if differences in the levels of production of aflatoxin by A. flavus could be explained by the accumulation of deleterious mutations due to a lack of recombination. Despite differences in the extent of recombination, variation in aflatoxin production is better explained by the demography and history of specific populations and may suggest important differences in the ecological roles of aflatoxin among populations. Furthermore, the association of aflatoxin production and populations provides a means of predicting the risk of aflatoxin contamination by determining the frequencies of isolates from low- and high-production populations.
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Affiliation(s)
- Milton T Drott
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Tatum R Satterlee
- Department of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jeffrey M Skerker
- Innovative Genomics Institute, The University of California, Berkeley, California, USA
| | | | - N Louise Glass
- Innovative Genomics Institute, The University of California, Berkeley, California, USA
- Department of Plant and Microbial Biology, The University of California, Berkeley, California, USA
- Environmental Genomics and Systems Biology, The Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Michael G Milgroom
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, New York, USA
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28
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Lücking R, Aime MC, Robbertse B, Miller AN, Ariyawansa HA, Aoki T, Cardinali G, Crous PW, Druzhinina IS, Geiser DM, Hawksworth DL, Hyde KD, Irinyi L, Jeewon R, Johnston PR, Kirk PM, Malosso E, May TW, Meyer W, Öpik M, Robert V, Stadler M, Thines M, Vu D, Yurkov AM, Zhang N, Schoch CL. Unambiguous identification of fungi: where do we stand and how accurate and precise is fungal DNA barcoding? IMA Fungus 2020; 11:14. [PMID: 32714773 PMCID: PMC7353689 DOI: 10.1186/s43008-020-00033-z] [Citation(s) in RCA: 174] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
True fungi (Fungi) and fungus-like organisms (e.g. Mycetozoa, Oomycota) constitute the second largest group of organisms based on global richness estimates, with around 3 million predicted species. Compared to plants and animals, fungi have simple body plans with often morphologically and ecologically obscure structures. This poses challenges for accurate and precise identifications. Here we provide a conceptual framework for the identification of fungi, encouraging the approach of integrative (polyphasic) taxonomy for species delimitation, i.e. the combination of genealogy (phylogeny), phenotype (including autecology), and reproductive biology (when feasible). This allows objective evaluation of diagnostic characters, either phenotypic or molecular or both. Verification of identifications is crucial but often neglected. Because of clade-specific evolutionary histories, there is currently no single tool for the identification of fungi, although DNA barcoding using the internal transcribed spacer (ITS) remains a first diagnosis, particularly in metabarcoding studies. Secondary DNA barcodes are increasingly implemented for groups where ITS does not provide sufficient precision. Issues of pairwise sequence similarity-based identifications and OTU clustering are discussed, and multiple sequence alignment-based phylogenetic approaches with subsequent verification are recommended as more accurate alternatives. In metabarcoding approaches, the trade-off between speed and accuracy and precision of molecular identifications must be carefully considered. Intragenomic variation of the ITS and other barcoding markers should be properly documented, as phylotype diversity is not necessarily a proxy of species richness. Important strategies to improve molecular identification of fungi are: (1) broadly document intraspecific and intragenomic variation of barcoding markers; (2) substantially expand sequence repositories, focusing on undersampled clades and missing taxa; (3) improve curation of sequence labels in primary repositories and substantially increase the number of sequences based on verified material; (4) link sequence data to digital information of voucher specimens including imagery. In parallel, technological improvements to genome sequencing offer promising alternatives to DNA barcoding in the future. Despite the prevalence of DNA-based fungal taxonomy, phenotype-based approaches remain an important strategy to catalog the global diversity of fungi and establish initial species hypotheses.
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Affiliation(s)
- Robert Lücking
- Botanischer Garten und Botanisches Museum, Freie Universität Berlin, Königin-Luise-Straße 6–8, 14195 Berlin, Germany
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
| | - M. Catherine Aime
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907 USA
| | - Barbara Robbertse
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, 45 Center Drive, Bethesda, MD 20892 USA
| | - Andrew N. Miller
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- Illinois Natural History Survey, University of Illinois, 1816 South Oak Street, Champaign, IL 61820-6970 USA
| | - Hiran A. Ariyawansa
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- Department of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipe City, Taiwan
| | - Takayuki Aoki
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- National Agriculture and Food Research Organization, Genetic Resources Center, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602 Japan
| | - Gianluigi Cardinali
- Department Pharmaceutical Sciences, University of Perugia, Via Borgo 20 Giugno, 74, Perugia, Italy
| | - Pedro W. Crous
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Wageningen University and Research Centre (WUR), Laboratory of Phytopathology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Irina S. Druzhinina
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- Microbiology and Applied Genomics Group, Research Area Biochemical Technology, Institute of Chemical, Environmental & Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria
- Jiangsu Provincial Key Lab of Organic Solid Waste Utilization, Nanjing Agricultural University, Nanjing, China
| | - David M. Geiser
- Department of Plant Pathology & Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802 USA
| | - David L. Hawksworth
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- Department of Life Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD UK
- Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, Surrey, TW9 3DS UK
- Geography and Environment, University of Southampton, Southampton, SO17 1BJ UK
- Jilin Agricultural University, Changchun, 130118 Jilin Province China
| | - Kevin D. Hyde
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Science, Kunming, 650201 Yunnan China
- Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100 Thailand
- World Agroforestry Centre, East and Central Asia, Kunming, 650201 Yunnan China
- Mushroom Research Foundation, 128 M.3 Ban Pa Deng T. Pa Pae, A. Mae Taeng, Chiang Rai, 50150 Thailand
| | - Laszlo Irinyi
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Faculty of Medicine and Health, Sydney Medical School, Westmead Clinical School, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead Hospital (Research and Education Network), Westmead Institute for Medical Research, Sydney, NSW Australia
| | - Rajesh Jeewon
- Department of Health Sciences, Faculty of Science, University of Mauritius, Reduit, Mauritius
| | - Peter R. Johnston
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- Manaaki Whenua – Landcare Research, Private Bag 92170, Auckland, 1142 New Zealand
| | | | - Elaine Malosso
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- Universidade Federal de Pernambuco, Centro de Biociências, Departamento de Micologia, Laboratório de Hifomicetos de Folhedo, Avenida da Engenharia, s/n Cidade Universitária, Recife, PE 50.740-600 Brazil
| | - Tom W. May
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- Royal Botanic Gardens Victoria, Birdwood Avenue, Melbourne, Victoria 3004 Australia
| | - Wieland Meyer
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Faculty of Medicine and Health, Sydney Medical School, Westmead Clinical School, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead Hospital (Research and Education Network), Westmead Institute for Medical Research, Sydney, NSW Australia
| | - Maarja Öpik
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- University of Tartu, 40 Lai Street, 51 005 Tartu, Estonia
| | - Vincent Robert
- Department Pharmaceutical Sciences, University of Perugia, Via Borgo 20 Giugno, 74, Perugia, Italy
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Marc Stadler
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- Department Microbial Drugs, Helmholtz Centre for Infection Research, and German Centre for Infection Research (DZIF), partner site Hannover-Braunschweig, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Marco Thines
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- Institute of Ecology, Evolution and Diversity, Goethe University, Max-von-Laue-Straße 9, 60439 Frankfurt (Main); Senckenberg Biodiversity and Climate Research Centre, Senckenberganlage 25, 60325 Frankfurt (Main), Germany
| | - Duong Vu
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Andrey M. Yurkov
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Ning Zhang
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901 USA
| | - Conrad L. Schoch
- International Commission on the Taxonomy of Fungi, Champaign, IL USA
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, 45 Center Drive, Bethesda, MD 20892 USA
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29
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Steenwyk JL, Lind AL, Ries LNA, Dos Reis TF, Silva LP, Almeida F, Bastos RW, Fraga da Silva TFDC, Bonato VLD, Pessoni AM, Rodrigues F, Raja HA, Knowles SL, Oberlies NH, Lagrou K, Goldman GH, Rokas A. Pathogenic Allodiploid Hybrids of Aspergillus Fungi. Curr Biol 2020; 30:2495-2507.e7. [PMID: 32502407 PMCID: PMC7343619 DOI: 10.1016/j.cub.2020.04.071] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 02/25/2020] [Accepted: 04/24/2020] [Indexed: 12/12/2022]
Abstract
Interspecific hybridization substantially alters genotypes and phenotypes and can give rise to new lineages. Hybrid isolates that differ from their parental species in infection-relevant traits have been observed in several human-pathogenic yeasts and plant-pathogenic filamentous fungi but have yet to be found in human-pathogenic filamentous fungi. We discovered 6 clinical isolates from patients with aspergillosis originally identified as Aspergillus nidulans (section Nidulantes) that are actually allodiploid hybrids formed by the fusion of Aspergillus spinulosporus with an unknown close relative of Aspergillus quadrilineatus, both in section Nidulantes. Evolutionary genomic analyses revealed that these isolates belong to Aspergillus latus, an allodiploid hybrid species. Characterization of diverse infection-relevant traits further showed that A. latus hybrid isolates are genomically and phenotypically heterogeneous but also differ from A. nidulans, A. spinulosporus, and A. quadrilineatus. These results suggest that allodiploid hybridization contributes to the genomic and phenotypic diversity of filamentous fungal pathogens of humans.
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Affiliation(s)
- Jacob L Steenwyk
- Department of Biological Sciences, Vanderbilt University, 465 21st Avenue South, Nashville, TN 37235, USA
| | - Abigail L Lind
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, 1211 Medical Center Drive, Nashville, TN 37232, USA; Gladstone Institute of Data Science and Biotechnology, San Francisco, CA 94158, USA
| | - Laure N A Ries
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Avenida Bandeirantes 3900, Vila Monte Alegre, 14049-900 Ribeirão Preto, São Paulo, Brazil; Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Departamento de Ciências Farmacêuticas, Universidade de São Paulo, Avenida do Café S/N, Ribeirão Preto 14040-903, Brazil
| | - Thaila F Dos Reis
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Avenida Bandeirantes 3900, Vila Monte Alegre, 14049-900 Ribeirão Preto, São Paulo, Brazil; Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Departamento de Ciências Farmacêuticas, Universidade de São Paulo, Avenida do Café S/N, Ribeirão Preto 14040-903, Brazil
| | - Lilian P Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Departamento de Ciências Farmacêuticas, Universidade de São Paulo, Avenida do Café S/N, Ribeirão Preto 14040-903, Brazil
| | - Fausto Almeida
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Avenida Bandeirantes 3900, Vila Monte Alegre, 14049-900 Ribeirão Preto, São Paulo, Brazil
| | - Rafael W Bastos
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Departamento de Ciências Farmacêuticas, Universidade de São Paulo, Avenida do Café S/N, Ribeirão Preto 14040-903, Brazil
| | - Thais Fernanda de Campos Fraga da Silva
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Avenida Bandeirantes 3900, Vila Monte Alegre, 14049-900 Ribeirão Preto, São Paulo, Brazil
| | - Vania L D Bonato
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Avenida Bandeirantes 3900, Vila Monte Alegre, 14049-900 Ribeirão Preto, São Paulo, Brazil
| | - André Moreira Pessoni
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Avenida Bandeirantes 3900, Vila Monte Alegre, 14049-900 Ribeirão Preto, São Paulo, Brazil
| | - Fernando Rodrigues
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4715-495 Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, 4715-495 Braga, Portugal
| | - Huzefa A Raja
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, 1400 Spring Garden Street, Greensboro, NC 27412, USA
| | - Sonja L Knowles
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, 1400 Spring Garden Street, Greensboro, NC 27412, USA
| | - Nicholas H Oberlies
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, 1400 Spring Garden Street, Greensboro, NC 27412, USA
| | - Katrien Lagrou
- Department of Microbiology, Immunology and Transplantation, Katholieke Universiteit Leuven, 3000 Leuven, Belgium; Department of Laboratory Medicine and National Reference Centre for Mycosis, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Departamento de Ciências Farmacêuticas, Universidade de São Paulo, Avenida do Café S/N, Ribeirão Preto 14040-903, Brazil.
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, 465 21st Avenue South, Nashville, TN 37235, USA; Department of Biomedical Informatics, Vanderbilt University School of Medicine, 1211 Medical Center Drive, Nashville, TN 37232, USA.
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30
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Xu Y, Zhou Y, Cao W, Liu H. Improved Production of Malic Acid in Aspergillus niger by Abolishing Citric Acid Accumulation and Enhancing Glycolytic Flux. ACS Synth Biol 2020; 9:1418-1425. [PMID: 32379964 DOI: 10.1021/acssynbio.0c00096] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Microbial fermentation was widely explored to produce malic acid. Previously, Aspergillus niger has been successfully engineered, and a high titer of malic acid was achieved with strain S575, but it also produced a high level of byproduct citric acid. Here, the capability of A. niger in malic acid biosynthesis was further improved by eliminating the accumulation of citric acid and enhancing glycolytic flux. Characterization of variant mutants suggested that disruption of cexA, a gene encoding citric acid transporter located on cell membrane, abolished citric acid accumulation. However, cexA-deficient strain S895 showed significantly decreased malic acid production. Further analysis of S895 indicated that the transcription level of genes involved in glucose transportation and glycolytic pathway was significantly reduced, and the corresponding enzyme activity was also lower than those of S575. Individual overexpression of genes encoding glucose transporter MstC and key enzymes (hexokinase HxkA, 6-phosphofructo-2-kinase PfkA, and pyruvate kinase PkiA) involved in irreversible reactions of glycolic pathway increased malic acid production. Accordingly, genes of mstC, hxkA, pfkA, and pkiA were overexpressed altogether in S895, and the resultant strain S1149 was constructed. The titer of malic acid in fed-batch fermentation with S1149 reached 201.13 g/L. Compared with S575, the byproduct of citric acid was completely abolished in S1149, and the ratio of malic acid/glucose was increased from 1.27 to 1.64 mol/mol, the highest yield reported so far, and the fermentation period was shortened from 9 to 8 days. Thus, a strain with great industrial application potential was developed by engineering nine genes in A. niger, and a pilot fermentation technology was exploited.
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Affiliation(s)
- Yongxue Xu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, 300457 Tianjin, China
| | - Yutao Zhou
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, 300457 Tianjin, China
| | - Wei Cao
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, 300457 Tianjin, China
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, 300457 Tianjin, China
| | - Hao Liu
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science & Technology, 300457 Tianjin, China
- Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control, Tianjin University of Science & Technology, 300457 Tianjin, China
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31
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Dar MS, Padder BA, Ahmad M, Sofi TA, Mir AA, Nabi A, Shah MD. Population structure of Venturia inaequalis, a hemibiotrophic fungus, under different host resistance specificities in the Kashmir valley. Arch Microbiol 2020; 202:2245-2253. [PMID: 32533207 DOI: 10.1007/s00203-020-01950-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/08/2020] [Accepted: 05/11/2020] [Indexed: 11/25/2022]
Abstract
Venturia inaequalis is a notorious fungal pathogen and show classical gene for gene interaction with its apple host. Neutral markers provide clues about history, evolutionary potential, genetic diversity and population structure of V. inaequalis. The genetic diversity and population structure of fungus indicates that the pathogen is highly diverse with the capacity to breach the scab resistance genes. In the present study, we collected 108 V. inaequalis isolates from three apple cultivars differing in Rvi1 resistance gene. Based on the AMOVA, the variation was mostly distributed among the isolates, providing evidence of non-existence of subpopulation in orchards thus founder population is difficult to arise in Kashmir apple orchards. Pair wise genetic differentiation is less due to regular occurrence of gene flow between the populations residing on different orchard as infected material is transported without stringent quarantine measures. Based on principal coordinate analysis and clustering algorithm as implemented in STRUCTURE, we observed admixture between the two subpopulations, which is quite low, suggesting the existence of pre-zygotic and post-zygotic barriers to gene flow and we cannot rule out the existence of other structures shared by accessions belonging to different varieties. Due to the continuous increase in introduction and monoculture of apple varieties, mixed orchard with different host resistance specificities are more suitable for managing the apple scab in Kashmir valley.
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Affiliation(s)
- M S Dar
- Plant Virology and Molecular Plant Pathology Laboratory, Division of Plant Pathology, SKUAST-Kashmir, Shalimar, Srinagar, 190025, India
| | - Bilal A Padder
- Plant Virology and Molecular Plant Pathology Laboratory, Division of Plant Pathology, SKUAST-Kashmir, Shalimar, Srinagar, 190025, India.
| | - Mushtaq Ahmad
- Plant Virology and Molecular Plant Pathology Laboratory, Division of Plant Pathology, SKUAST-Kashmir, Shalimar, Srinagar, 190025, India
| | - T A Sofi
- Plant Virology and Molecular Plant Pathology Laboratory, Division of Plant Pathology, SKUAST-Kashmir, Shalimar, Srinagar, 190025, India
| | - A A Mir
- Plant Virology and Molecular Plant Pathology Laboratory, Division of Plant Pathology, SKUAST-Kashmir, Shalimar, Srinagar, 190025, India
| | - Asha Nabi
- Division of Plant Pathology, Faculty of Agriculture, SKUAST-K, Sopore, Wadura, 193201, India
| | - M D Shah
- Plant Virology and Molecular Plant Pathology Laboratory, Division of Plant Pathology, SKUAST-Kashmir, Shalimar, Srinagar, 190025, India
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32
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Jørgensen TR, Burggraaf AM, Arentshorst M, Schutze T, Lamers G, Niu J, Kwon MJ, Park J, Frisvad JC, Nielsen KF, Meyer V, van den Hondel CA, Dyer PS, Ram AF. Identification of SclB, a Zn(II)2Cys6 transcription factor involved in sclerotium formation in Aspergillus niger. Fungal Genet Biol 2020; 139:103377. [DOI: 10.1016/j.fgb.2020.103377] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 02/07/2020] [Accepted: 02/14/2020] [Indexed: 10/24/2022]
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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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34
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Li Z, Li X, Jian M, Geleta GS, Wang Z. Two-Dimensional Layered Nanomaterial-Based Electrochemical Biosensors for Detecting Microbial Toxins. Toxins (Basel) 2019; 12:E20. [PMID: 31906152 PMCID: PMC7020412 DOI: 10.3390/toxins12010020] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/18/2019] [Accepted: 12/27/2019] [Indexed: 01/04/2023] Open
Abstract
Toxin detection is an important issue in numerous fields, such as agriculture/food safety, environmental monitoring, and homeland security. During the past two decades, nanotechnology has been extensively used to develop various biosensors for achieving fast, sensitive, selective and on-site analysis of toxins. In particular, the two dimensional layered (2D) nanomaterials (such as graphene and transition metal dichalcogenides (TMDs)) and their nanocomposites have been employed as label and/or biosensing transducers to construct electrochemical biosensors for cost-effective detection of toxins with high sensitivity and specificity. This is because the 2D nanomaterials have good electrical conductivity and a large surface area with plenty of active groups for conjugating 2D nanomaterials with the antibodies and/or aptamers of the targeted toxins. Herein, we summarize recent developments in the application of 2D nanomaterial-based electrochemical biosensors for detecting toxins with a particular focus on microbial toxins including bacterial toxins, fungal toxins and algal toxins. The integration of 2D nanomaterials with some existing antibody/aptamer technologies into electrochemical biosensors has led to an unprecedented impact on improving the assaying performance of microbial toxins, and has shown great promise in public health and environmental protection.
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Affiliation(s)
- Zhuheng Li
- Jilin Provincial Institute of Education, Changchun 130022, China;
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science, Changchun 130022, China; (X.L.); (M.J.)
| | - Xiaotong Li
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science, Changchun 130022, China; (X.L.); (M.J.)
| | - Minghong Jian
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science, Changchun 130022, China; (X.L.); (M.J.)
| | - Girma Selale Geleta
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science, Changchun 130022, China; (X.L.); (M.J.)
- Department of Chemistry, College of Natural Sciences, Jimma University, Jimma 378, Ethiopia
| | - Zhenxin Wang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science, Changchun 130022, China; (X.L.); (M.J.)
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35
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Bouti K, Verheecke‐Vaessen C, Mokrane S, Meklat A, Djemouai N, Sabaou N, Mathieu F, Riba A. Polyphasic characterization of
Aspergillus
section
Flavi
isolated from animal feeds in Algeria. J Food Saf 2019. [DOI: 10.1111/jfs.12743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Karima Bouti
- Laboratoire de Biologie des Systèmes MicrobiensEcole Normale Supérieure de Kouba Alger Algeria
| | - Carol Verheecke‐Vaessen
- Applied Mycology Group, Environment and AgriFood ThemeCranfield University Cranfield UK
- Laboratoire de Génie ChimiqueUniversité de Toulouse, CNRS Toulouse France
| | - Salim Mokrane
- Laboratoire de Biologie des Systèmes MicrobiensEcole Normale Supérieure de Kouba Alger Algeria
| | - Atika Meklat
- Laboratoire de Biologie des Systèmes MicrobiensEcole Normale Supérieure de Kouba Alger Algeria
- Département de Biologie et Physiologie Cellulaire, Faculté des Sciences de la Nature et de la VieUniversité Saad Dahlab Blida Algeria
| | - Nadjette Djemouai
- Laboratoire de Biologie des Systèmes MicrobiensEcole Normale Supérieure de Kouba Alger Algeria
- Laboratoire de Biologie et Physiologie des OrganismesUniversité des Sciences et de la Technologie Houari Boumediene Bab Ezzouar (USTHB) Algiers Algeria
| | - Nasserdine Sabaou
- Laboratoire de Biologie des Systèmes MicrobiensEcole Normale Supérieure de Kouba Alger Algeria
| | - Florence Mathieu
- Applied Mycology Group, Environment and AgriFood ThemeCranfield University Cranfield UK
| | - Amar Riba
- Laboratoire de Biologie des Systèmes MicrobiensEcole Normale Supérieure de Kouba Alger Algeria
- Département de Biologie, Faculté des SciencesUniversité M'Hamed Bougara Boumerdès Algeria
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Zyoud SH. Global scientific trends on aflatoxin research during 1998-2017: a bibliometric and visualized study. J Occup Med Toxicol 2019; 14:27. [PMID: 31832075 PMCID: PMC6873441 DOI: 10.1186/s12995-019-0248-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/13/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Aflatoxins are fungal metabolites associated with contaminated food products. Intake of aflatoxin-contaminated food results in serious health hazards and even death. Therefore, the aim of this study is to evaluate the global scientific output of research of aflatoxin by using bibliometric techniques. METHODS This bibliometric study was conducted using Scopus database and classified the retrieved publications were classified from different aspects, including the countries/region of focus, journals, authors, institutes, citations, and content analysis to discover any hot and emerging topics. In addition, the bibliometric analysis of the international collaborative network and hot research topics were generated by VOSviewer© software version 1.6.10. The publication period was restricted in the search for two decades (1998-2017). RESULTS The search engine of the Scopus database found 9845 documents published in the field of aflatoxin. The USA is the top publishing source in the world (22.85%), followed by China (11.85%), India (9.32%), and Italy (5.25%). In earlier years, researchers focused on terms related to the topics of "sources and biosynthesis of aflatoxin", "health effects by aflatoxin", and "detoxification and treatment of aflatoxin". However, in recent years, researchers pay more attention to the topic of detection and quantification of aflatoxin. CONCLUSIONS The quantity of research in global aflatoxin has substantially increased over the past two decades. The evaluation of the historical status and development trend in aflatoxin scientific research can guide future research, and ultimately provide the basis for improving management procedures for governmental decisions, healthcare, industries, and educational institutions.
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Affiliation(s)
- Sa’ed H. Zyoud
- Poison Control and Drug Information Center (PCDIC), College of Medicine and Health Sciences, An-Najah National University, Nablus, 44839 Palestine
- Department of Clinical and Community Pharmacy, College of Medicine and Health Sciences, An-Najah National University, Nablus, 44839 Palestine
- Clinical Research Centre, An-Najah National University Hospital, Nablus, 44839 Palestine
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37
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Gostinčar C, Turk M, Zajc J, Gunde‐Cimerman N. Fifty Aureobasidium pullulans genomes reveal a recombining polyextremotolerant generalist. Environ Microbiol 2019; 21:3638-3652. [PMID: 31112354 PMCID: PMC6852026 DOI: 10.1111/1462-2920.14693] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 04/17/2019] [Accepted: 05/20/2019] [Indexed: 01/31/2023]
Abstract
The black yeast Aureobasidium pullulans is a textbook example of a generalistic and ubiquitous fungus thriving in a wide variety of environments. To investigate whether A. pullulans is a true generalist, or alternatively, whether part of its versatility can be attributed to intraspecific specialization masked by cryptic diversification undetectable by traditional phylogenetic analyses, we sequenced and analysed the genomes of 50 strains of A. pullulans from different habitats and geographic locations. No population structure was observed in the sequenced strains. Decay of linkage disequilibrium over shorter physical distances (<100 bp) than in many sexually reproducing fungi indicates a high level of recombination in the species. A homothallic mating locus was found in all of the sequenced genomes. Aureobasidium pullulans appears to have a homogeneous population genetics structure, which is best explained by good dispersal and high levels of recombination. This means that A. pullulans is a true generalist that can inhabit different habitats without substantial specialization to any of these habitats at the genomic level. Furthermore, in the future, the high level of A. pullulans recombination can be exploited for the identification of genomic loci that are involved in the many biotechnologically useful traits of this black yeast.
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Affiliation(s)
- Cene Gostinčar
- Department of Biology, Biotechnical FacultyUniversity of Ljubljana, Jamnikarjeva 101, SI‐1000LjubljanaSlovenia
- Lars Bolund Institute of Regenerative Medicine, BGI‐QingdaoQingdao 266555China
| | - Martina Turk
- Department of Biology, Biotechnical FacultyUniversity of Ljubljana, Jamnikarjeva 101, SI‐1000LjubljanaSlovenia
| | - Janja Zajc
- Department of Biology, Biotechnical FacultyUniversity of Ljubljana, Jamnikarjeva 101, SI‐1000LjubljanaSlovenia
- National Institute of BiologyVečna pot 111, SI‐1000LjubljanaSlovenia
| | - Nina Gunde‐Cimerman
- Department of Biology, Biotechnical FacultyUniversity of Ljubljana, Jamnikarjeva 101, SI‐1000LjubljanaSlovenia
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38
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Peterson SW, Jurjević Ž. The Talaromyces pinophilus species complex. Fungal Biol 2019; 123:745-762. [DOI: 10.1016/j.funbio.2019.06.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 04/16/2019] [Accepted: 06/19/2019] [Indexed: 01/26/2023]
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39
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Gostinčar C, Sun X, Zajc J, Fang C, Hou Y, Luo Y, Gunde-Cimerman N, Song Z. Population Genomics of an Obligately Halophilic Basidiomycete Wallemia ichthyophaga. Front Microbiol 2019; 10:2019. [PMID: 31551960 PMCID: PMC6738226 DOI: 10.3389/fmicb.2019.02019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/19/2019] [Indexed: 11/15/2022] Open
Abstract
Background Wallemia ichthyophaga is a highly specialized basidiomycetous fungus. It is one of the most halophilic fungi ever described, only able to grow at low water activity. This specialization is thought to explain why it is only rarely isolated from nature. Results Genomes of 21 W. ichthyophaga strains were sequenced with PE150 reads on BGISEQ500 platform. The genomes shared high similarity with the reference genome of the species, they were all smaller than 10 Mbp and had a low number of predicted genes. Groups of strains isolated in the same location encompassed clones as well as very divergent strains. There was little concordance between phylogenies of predicted genes. Linkage disequilibrium of pairs of polymorphic loci decayed relatively quickly as a function of distance between the loci (LD decay distance 1270 bp). For the first time a putative mating-type locus was identified in the genomes of W. ichthyophaga. Conclusion Based on the comparison of W. ichthyophaga genomes it appears that some phylogenetic lineages of the species can persist in the same location over at least several years. Apart from this, the differences between the strains do not reflect the isolation habitat or geographic location. Together with results supporting the existence of (sexual) recombination in W. ichthyophaga, the presented results indicate that strains of W. ichthyophaga can form a single recombining population even between different habitats and over large geographical distances.
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Affiliation(s)
- Cene Gostinčar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.,Lars Bolund Institute of Regenerative Medicine, BGI-Qingdao, Qingdao, China
| | - Xiaohuan Sun
- BGI-Shenzhen, Shenzhen, China.,China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Janja Zajc
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.,National Institute of Biology, Ljubljana, Slovenia
| | - Chao Fang
- BGI-Shenzhen, Shenzhen, China.,China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Yong Hou
- BGI-Shenzhen, Shenzhen, China.,China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Yonglun Luo
- Lars Bolund Institute of Regenerative Medicine, BGI-Qingdao, Qingdao, China.,BGI-Shenzhen, Shenzhen, China.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Nina Gunde-Cimerman
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Zewei Song
- BGI-Shenzhen, Shenzhen, China.,China National GeneBank, BGI-Shenzhen, Shenzhen, China
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40
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Norlia M, Jinap S, Nor-Khaizura MAR, Radu S, Chin CK, Samsudin NIP, Farawahida AH. Molecular Characterisation of Aflatoxigenic and Non-Aflatoxigenic Strains of Aspergillus Section Flavi Isolated from Imported Peanuts along the Supply Chain in Malaysia. Toxins (Basel) 2019; 11:E501. [PMID: 31470527 PMCID: PMC6784170 DOI: 10.3390/toxins11090501] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 06/25/2019] [Accepted: 07/10/2019] [Indexed: 11/16/2022] Open
Abstract
Peanuts are widely consumed in many local dishes in southeast Asian countries, especially in Malaysia which is one of the major peanut-importing countries in this region. Therefore, Aspergillus spp. and aflatoxin contamination in peanuts during storage are becoming major concerns due to the tropical weather in this region that favours the growth of aflatoxigenic fungi. The present study thus aimed to molecularly identify and characterise the Aspergillus section Flavi isolated from imported peanuts in Malaysia. The internal transcribed spacer (ITS) and β-tubulin sequences were used to confirm the species and determine the phylogenetic relationship among the isolates, while aflatoxin biosynthesis genes (aflR, aflP (omtA), aflD (nor-1), aflM (ver-1), and pksA) were targeted in a multiplex PCR to determine the toxigenic potential. A total of 76 and one isolates were confirmed as A. flavus and A. tamarii, respectively. The Maximum Likelihood (ML) phylogenetic tree resolved the species into two different clades in which all A. flavus (both aflatoxigenic and non-aflatoxigenic) were grouped in the same clade and A. tamarii was grouped in a different clade. The aflatoxin biosynthesis genes were detected in all aflatoxigenic A. flavus while the non-aflatoxigenic A. flavus failed to amplify at least one of the genes. The results indicated that both aflatoxigenic and non-aflatoxigenic A. flavus could survive in imported peanuts and, thus, appropriate storage conditions preferably with low temperature should be considered to avoid the re-emergence of aflatoxigenic A. flavus and the subsequent aflatoxin production in peanuts during storage.
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Affiliation(s)
- Mahror Norlia
- Department of Food Science and Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
- School of Industrial Technology, Universiti Sains Malaysia, Minden 11800, Pulau Pinang, Malaysia
| | - Selamat Jinap
- Department of Food Science and Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia.
- Laboratory of Food Safety and Food Integrity, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia.
| | - Mahmud Ab Rashid Nor-Khaizura
- Department of Food Science and Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
| | - Son Radu
- Department of Food Science and Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
- Laboratory of Food Safety and Food Integrity, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
| | - Cheow Keat Chin
- Food Safety and Quality Division, Ministry of Health Malaysia, Putrajaya 62675, Malaysia
| | - Nik Iskandar Putra Samsudin
- Department of Food Science and Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
- Laboratory of Food Safety and Food Integrity, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
| | - Abdul Halim Farawahida
- Department of Food Science and Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
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41
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Dooso Oloo R, Okoth S, Wachira P, Mutiga S, Ochieng P, Kago L, Nganga F, Domelevo Entfellner JB, Ghimire S. Genetic Profiling of Aspergillus Isolates with Varying Aflatoxin Production Potential from Different Maize-Growing Regions of Kenya. Toxins (Basel) 2019; 11:toxins11080467. [PMID: 31404960 PMCID: PMC6723045 DOI: 10.3390/toxins11080467] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 07/25/2019] [Accepted: 08/05/2019] [Indexed: 01/12/2023] Open
Abstract
Highly toxigenic strains of Aspergillus flavus have been reported to frequently contaminate maize, causing fatal aflatoxin poisoning in Kenya. To gain insights into the environmental and genetic factors that influence toxigenicity, fungi (n = 218) that were culturally identified as A. flavus were isolated from maize grains samples (n = 120) from three regions of Kenya. The fungi were further characterized to confirm their identities using a PCR-sequence analysis of the internal transcribed spacer (ITS) region of rDNA which also revealed all of them to be A. flavus. A subset of 72 isolates representing ITS sequence-based phylogeny cluster and the agroecological origin of maize samples was constituted for subsequent analysis. The analysis of partial calmodulin gene sequences showed that the subset consisted of A. flavus (87%) and Aspergillus minisclerotigenes (13%). No obvious association was detected between the presence of seven aflatoxin biosynthesis genes and fungal species or region. However, the presence of the aflD and aflS genes showed some association with aflatoxin production. The assessment of toxigenicity showed higher aflatoxin production potential in A. minisclerotigenes isolates. Given that A. minisclerotigenes were mainly observed in maize samples from Eastern Kenya, a known aflatoxin hotspot, we speculate that production of copious aflatoxin is an adaptative trait of this recently discovered species in the region.
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Affiliation(s)
- Richard Dooso Oloo
- School of Biological Sciences, University of Nairobi, P.O. Box 30197-00100 Nairobi, Kenya
- Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub, P.O. Box 30709-00100 Nairobi, Kenya
| | - Sheila Okoth
- School of Biological Sciences, University of Nairobi, P.O. Box 30197-00100 Nairobi, Kenya
| | - Peter Wachira
- School of Biological Sciences, University of Nairobi, P.O. Box 30197-00100 Nairobi, Kenya
| | - Samuel Mutiga
- Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub, P.O. Box 30709-00100 Nairobi, Kenya
- Department of Plant Pathology, University of Arkansas, Fayetteville, AR 72701, USA
| | - Phillis Ochieng
- Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub, P.O. Box 30709-00100 Nairobi, Kenya
| | - Leah Kago
- Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub, P.O. Box 30709-00100 Nairobi, Kenya
| | - Fredrick Nganga
- Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub, P.O. Box 30709-00100 Nairobi, Kenya
| | - Jean-Baka Domelevo Entfellner
- Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub, P.O. Box 30709-00100 Nairobi, Kenya
| | - Sita Ghimire
- Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub, P.O. Box 30709-00100 Nairobi, Kenya.
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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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Hind KR, Starko S, Burt JM, Lemay MA, Salomon AK, Martone PT. Trophic control of cryptic coralline algal diversity. Proc Natl Acad Sci U S A 2019; 116:15080-15085. [PMID: 31285351 PMCID: PMC6660763 DOI: 10.1073/pnas.1900506116] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Understanding how trophic dynamics drive variation in biodiversity is essential for predicting the outcomes of trophic downgrading across the world's ecosystems. However, assessing the biodiversity of morphologically cryptic lineages can be problematic, yet may be crucial to understanding ecological patterns. Shifts in keystone predation that favor increases in herbivore abundance tend to have negative consequences for the biodiversity of primary producers. However, in nearshore ecosystems, coralline algal cover increases when herbivory is intense, suggesting that corallines may uniquely benefit from trophic downgrading. Because many coralline algal species are morphologically cryptic and their diversity has been globally underestimated, increasing the resolution at which we distinguish species could dramatically alter our conclusions about the consequences of trophic dynamics for this group. In this study, we used DNA barcoding to compare the diversity and composition of cryptic coralline algal assemblages at sites that differ in urchin biomass and keystone predation by sea otters. We show that while coralline cover is greater in urchin-dominated sites (or "barrens"), which are subject to intense grazing, coralline assemblages in these urchin barrens are significantly less diverse than in kelp forests and are dominated by only 1 or 2 species. These findings clarify how food web structure relates to coralline community composition and reconcile patterns of total coralline cover with the widely documented pattern that keystone predation promotes biodiversity. Shifts in coralline diversity and distribution associated with transitions from kelp forests to urchin barrens could have ecosystem-level effects that would be missed by ignoring cryptic species' identities.
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Affiliation(s)
- Katharine R Hind
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
- Hakai Institute, Heriot Bay, BC, Canada V0P 1H0
| | - Samuel Starko
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
- Hakai Institute, Heriot Bay, BC, Canada V0P 1H0
| | - Jenn M Burt
- Hakai Institute, Heriot Bay, BC, Canada V0P 1H0
- School of Resource and Environmental Management, Simon Fraser University, Burnaby, BC, Canada V5A 1S6
| | | | - Anne K Salomon
- Hakai Institute, Heriot Bay, BC, Canada V0P 1H0
- School of Resource and Environmental Management, Simon Fraser University, Burnaby, BC, Canada V5A 1S6
| | - Patrick T Martone
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada V6T 1Z4;
- Hakai Institute, Heriot Bay, BC, Canada V0P 1H0
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44
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Fungal species boundaries in the genomics era. Fungal Genet Biol 2019; 131:103249. [PMID: 31279976 DOI: 10.1016/j.fgb.2019.103249] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 05/21/2019] [Accepted: 06/28/2019] [Indexed: 12/30/2022]
Abstract
Genomic data has opened new possibilities to understand how organisms change over time, and could enable the discovery of previously undescribed species. Although taxonomy used to be based on phenotypes, molecular data has frequently revealed that morphological traits are insufficient to describe biodiversity. Genomics holds the promise of revealing even more genetic discontinuities, but the parameters on how to describe species from genomic data remain unclear. Fungi have been a successful case in which the use of molecular markers has uncovered the existence of genetic boundaries where no crosses are possible. In this minireview, we highlight recent advances, propose a set of standards to use genomic sequences to uncover species boundaries, point out potential pitfalls, and present possible future research directions.
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Rudramurthy SM, Paul RA, Chakrabarti A, Mouton JW, Meis JF. Invasive Aspergillosis by Aspergillus flavus: Epidemiology, Diagnosis, Antifungal Resistance, and Management. J Fungi (Basel) 2019; 5:jof5030055. [PMID: 31266196 PMCID: PMC6787648 DOI: 10.3390/jof5030055] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 06/28/2019] [Accepted: 06/29/2019] [Indexed: 12/12/2022] Open
Abstract
Aspergillus flavus is the second most common etiological agent of invasive aspergillosis (IA) after A. fumigatus. However, most literature describes IA in relation to A. fumigatus or together with other Aspergillus species. Certain differences exist in IA caused by A. flavus and A. fumigatus and studies on A. flavus infections are increasing. Hence, we performed a comprehensive updated review on IA due to A. flavus. A. flavus is the cause of a broad spectrum of human diseases predominantly in Asia, the Middle East, and Africa possibly due to its ability to survive better in hot and arid climatic conditions compared to other Aspergillus spp. Worldwide, ~10% of cases of bronchopulmonary aspergillosis are caused by A. flavus. Outbreaks have usually been associated with construction activities as invasive pulmonary aspergillosis in immunocompromised patients and cutaneous, subcutaneous, and mucosal forms in immunocompetent individuals. Multilocus microsatellite typing is well standardized to differentiate A. flavus isolates into different clades. A. flavus is intrinsically resistant to polyenes. In contrast to A. fumigatus, triazole resistance infrequently occurs in A. flavus and is associated with mutations in the cyp51C gene. Overexpression of efflux pumps in non-wildtype strains lacking mutations in the cyp51 gene can also lead to high voriconazole minimum inhibitory concentrations. Voriconazole remains the drug of choice for treatment, and amphotericin B should be avoided. Primary therapy with echinocandins is not the first choice but the combination with voriconazole or as monotherapy may be used when the azoles and amphotericin B are contraindicated.
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Affiliation(s)
- Shivaprakash M Rudramurthy
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Research, Chandigarh 160012, India.
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, 3015GD Rotterdam, The Netherlands.
| | - Raees A Paul
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Research, Chandigarh 160012, India
| | - Arunaloke Chakrabarti
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Research, Chandigarh 160012, India
| | - Johan W Mouton
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, 3015GD Rotterdam, The Netherlands
| | - Jacques F Meis
- Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital (CWZ) and Center of Expertise, 6532SZ Nijmegen, The Netherlands
- Center of Expertise in Mycology Radboudumc/CWZ, 6532SZ Nijmegen, The Netherlands
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Karimizadeh Esfahani M, Eslampoor A, Dolatabadi S, Najafzadeh MJ, Houbraken J. First case of fungal keratitis due to Aspergillus minisclerotigenes in Iran. Curr Med Mycol 2019; 5:45-48. [PMID: 31321339 PMCID: PMC6626709 DOI: 10.18502/cmm.5.2.1162] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Background and Purpose: Herein, we report the first case of fungal keratitis due to Aspergillusminisclerotigenes in a 68-year-old rural woman admitted to the Ophthalmology Center of Khatam-Al-Anbia Hospital in Mashhad, northeast of Iran. Case report: The patient presented with severe pain, burning, foreign body sensation, and reduced vision in her right eye. She had long-term uncontrolled diabetes and was not able to close her eye due to an anatomical problem with the eyelid. The cornea smear sample was cultured, and the fungus was initially identified as Aspergillusflavus. The isolated strain was further identified by sequencing a part of the calmodulin gene as A. minisclerotigenes. The patient did not respond to any antifungal treatments (e.g., amphotericin B and voriconazole drops, and fluconazole 300 mg/day); therefore, she was eventually subjected to corneal transplantation surgery. Conclusion: Fungal keratitis can be caused by the less common species. The reliable identification of the causative agents can be accomplished by the implementation of molecular methods.
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Affiliation(s)
- Mahmoud Karimizadeh Esfahani
- Department of Parasitology and Mycology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Alireza Eslampoor
- Eye Research Centre, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Somayeh Dolatabadi
- Faculty of Engineering, Sabzevar University of New Technology, Sabzevar, Iran
| | - Mohammad J Najafzadeh
- Department of Parasitology and Mycology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Jos Houbraken
- Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands
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47
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Affiliation(s)
- Kerry O'Donnell
- Microbial Properties Research Unit, National Center for Agricultural Utilization Research, United States Department of Agriculture, Agricultural Research Service, Peoria, Illinois 61604-3999
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48
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Chaverri P, Samuels GJ, Stewart EL. Hypocrea virens sp. nov., the teleomorph of Trichoderma virens. Mycologia 2019. [DOI: 10.1080/00275514.2001.12063245] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Priscila Chaverri
- United States Department of Agriculture, Agricultural Research Service, Systematic Botany and Mycology Lab., Rm. 304, B-011A, BARC-W, Beltsville, Maryland 20705-2350
| | - Gary J. Samuels
- United States Department of Agriculture, Agricultural Research Service, Systematic Botany and Mycology Lab., Rm. 304, B-011A, BARC-W, Beltsville, Maryland 20705-2350
| | - Elwin L. Stewart
- The Pennsylvania State University, Department of Plant Pathology, 212 Buckhout Lab., University Park, Pennsylvania 16802
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49
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Kroken S, Taylor JW. A gene genealogical approach to recognize phylogenetic species boundaries in the lichenized fungusLetharia. Mycologia 2019. [DOI: 10.1080/00275514.2001.12061278] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Scott Kroken
- Department of Plant and Microbial Biology, 321 Koshland Hall, University of California, Berkeley, California, USA 94720-3102
| | - John W. Taylor
- Department of Plant and Microbial Biology, 321 Koshland Hall, University of California, Berkeley, California, USA 94720-3102
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50
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Tessmann DJ, Charudattan R, Kistler HC, Rosskopf EN. A molecular characterization of Cercospora species pathogenic to water hyacinth and emendation of C. piaropi. Mycologia 2019. [DOI: 10.1080/00275514.2001.12063164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Dauri J. Tessmann
- University of Florida, Plant Pathology Department, 1453 Fifield Hall, Gainesville, Florida 32611-0680
| | - Raghavan Charudattan
- University of Florida, Plant Pathology Department, 1453 Fifield Hall, Gainesville, Florida 32611-0680
| | - H. Corby Kistler
- USDA-ARS, Cereal Disease Laboratory, Plant Pathology Department, University of Minnesota, St. Paul, Minnesota 55108
| | - Erin N. Rosskopf
- USDA-ARS, Horticultural Research Unit, 2001 S. Rock Road, Ft. Pierce, Florida 34945
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