1
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van Rhijn N, Zhao C, Al-Furaji N, Storer ISR, Valero C, Gago S, Chown H, Baldin C, Grant RF, Bin Shuraym H, Ivanova L, Kniemeyer O, Krüger T, Bignell E, Goldman GH, Amich J, Delneri D, Bowyer P, Brakhage AA, Haas H, Bromley MJ. Functional analysis of the Aspergillus fumigatus kinome identifies a druggable DYRK kinase that regulates septal plugging. Nat Commun 2024; 15:4984. [PMID: 38862481 PMCID: PMC11166925 DOI: 10.1038/s41467-024-48592-8] [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: 05/31/2023] [Accepted: 05/03/2024] [Indexed: 06/13/2024] Open
Abstract
More than 10 million people suffer from lung diseases caused by the pathogenic fungus Aspergillus fumigatus. Azole antifungals represent first-line therapeutics for most of these infections but resistance is rising, therefore the identification of antifungal targets whose inhibition synergises with the azoles could improve therapeutic outcomes. Here, we generate a library of 111 genetically barcoded null mutants of Aspergillus fumigatus in genes encoding protein kinases, and show that loss of function of kinase YakA results in hypersensitivity to the azoles and reduced pathogenicity. YakA is an orthologue of Candida albicans Yak1, a TOR signalling pathway kinase involved in modulation of stress responsive transcriptional regulators. We show that YakA has been repurposed in A. fumigatus to regulate blocking of the septal pore upon exposure to stress. Loss of YakA function reduces the ability of A. fumigatus to penetrate solid media and to grow in mouse lung tissue. We also show that 1-ethoxycarbonyl-beta-carboline (1-ECBC), a compound previously shown to inhibit C. albicans Yak1, prevents stress-mediated septal spore blocking and synergises with the azoles to inhibit A. fumigatus growth.
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Affiliation(s)
- Norman van Rhijn
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Can Zhao
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Narjes Al-Furaji
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- Department of Pharmacology, College of Medicine, University of Kerbala, Kerbala, Iraq
| | - Isabelle S R Storer
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Clara Valero
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Sara Gago
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Harry Chown
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Clara Baldin
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Rachael-Fortune Grant
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Hajer Bin Shuraym
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences, 11481, Riyadh, Saudi Arabia
| | - Lia Ivanova
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (Leibniz-HKI), Jena, Germany
| | - Olaf Kniemeyer
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (Leibniz-HKI), Jena, Germany
| | - Thomas Krüger
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (Leibniz-HKI), Jena, Germany
| | - Elaine Bignell
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- MRC Centre for Medical Mycology, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Jorge Amich
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- Mycology Reference Laboratory (Laboratorio de Referencia e Investigación en Micología [LRIM]), National Centre for Microbiology, Instituto de Salud Carlos III (ISCIII), Majadahonda, Madrid, Spain
| | - Daniela Delneri
- Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Paul Bowyer
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Axel A Brakhage
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences, 11481, Riyadh, Saudi Arabia
- Department of Microbiology and Molecular Biology, Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Hubertus Haas
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Michael J Bromley
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
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2
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Xie J, Rybak JM, Martin-Vicente A, Guruceaga X, Thorn HI, Nywening AV, Ge W, Parker JE, Kelly SL, Rogers PD, Fortwendel JR. The sterol C-24 methyltransferase encoding gene, erg6, is essential for viability of Aspergillus species. Nat Commun 2024; 15:4261. [PMID: 38769341 PMCID: PMC11106247 DOI: 10.1038/s41467-024-48767-3] [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: 08/28/2023] [Accepted: 05/09/2024] [Indexed: 05/22/2024] Open
Abstract
Triazoles, the most widely used class of antifungal drugs, inhibit the biosynthesis of ergosterol, a crucial component of the fungal plasma membrane. Inhibition of a separate ergosterol biosynthetic step, catalyzed by the sterol C-24 methyltransferase Erg6, reduces the virulence of pathogenic yeasts, but its effects on filamentous fungal pathogens like Aspergillus fumigatus remain unexplored. Here, we show that the lipid droplet-associated enzyme Erg6 is essential for the viability of A. fumigatus and other Aspergillus species, including A. lentulus, A. terreus, and A. nidulans. Downregulation of erg6 causes loss of sterol-rich membrane domains required for apical extension of hyphae, as well as altered sterol profiles consistent with the Erg6 enzyme functioning upstream of the triazole drug target, Cyp51A/Cyp51B. Unexpectedly, erg6-repressed strains display wild-type susceptibility against the ergosterol-active triazole and polyene antifungals. Finally, we show that erg6 repression results in significant reduction in mortality in a murine model of invasive aspergillosis. Taken together with recent studies, our work supports Erg6 as a potentially pan-fungal drug target.
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Affiliation(s)
- Jinhong Xie
- Graduate Program in Pharmaceutical Sciences, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Jeffrey M Rybak
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Adela Martin-Vicente
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Xabier Guruceaga
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Harrison I Thorn
- Graduate Program in Pharmaceutical Sciences, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Ashley V Nywening
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
- Integrated Program in Biomedical Sciences, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Microbiology, Immunology, and Biochemistry, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Wenbo Ge
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Josie E Parker
- Molecular Biosciences Division, School of Biosciences, Cardiff University, Cardiff, Wales, UK
| | - Steven L Kelly
- Institute of Life Science, Swansea University Medical School, Swansea, Wales, UK
| | - P David Rogers
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Jarrod R Fortwendel
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA.
- Department of Microbiology, Immunology, and Biochemistry, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA.
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3
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Atanasoff-Kardjalieff AK, Berger H, Steinert K, Janevska S, Ponts N, Humpf HU, Kalinina S, Studt-Reinhold L. Incorporation of the histone variant H2A.Z counteracts gene silencing mediated by H3K27 trimethylation in Fusarium fujikuroi. Epigenetics Chromatin 2024; 17:7. [PMID: 38509556 PMCID: PMC10953111 DOI: 10.1186/s13072-024-00532-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Accepted: 02/15/2024] [Indexed: 03/22/2024] Open
Abstract
BACKGROUND Fusarium fujikuroi is a pathogen of rice causing diverse disease symptoms such as 'bakanae' or stunting, most likely due to the production of various natural products (NPs) during infection. Fusaria have the genetic potential to synthesize a plethora of these compounds with often diverse bioactivity. The capability to synthesize NPs exceeds the number of those being produced by far, implying a gene regulatory network decisive to induce production. One such regulatory layer is the chromatin structure and chromatin-based modifications associated with it. One prominent example is the exchange of histones against histone variants such as the H2A variant H2A.Z. Though H2A.Z already is well studied in several model organisms, its regulatory functions are not well understood. Here, we used F. fujikuroi as a model to explore the role of the prominent histone variant FfH2A.Z in gene expression within euchromatin and facultative heterochromatin. RESULTS Through the combination of diverse '-omics' methods, we show the global distribution of FfH2A.Z and analyze putative crosstalks between the histone variant and two prominent histone marks, i.e., H3K4me3 and H3K27me3, important for active gene transcription and silencing, respectively. We demonstrate that, if FfH2A.Z is positioned at the + 1-nucleosome, it poises chromatin for gene transcription, also within facultative heterochromatin. Lastly, functional characterization of FfH2A.Z overexpression and depletion mutants revealed that FfH2A.Z is important for wild type-like fungal development and secondary metabolism. CONCLUSION In this study, we show that the histone variant FfH2A.Z is a mark of positive gene transcription and acts independently of the chromatin state most likely through the stabilization of the + 1-nucleosome. Furthermore, we demonstrate that FfH2A.Z depletion does not influence the establishment of both H3K27me3 and H3K4me3, thus indicating no crosstalk between FfH2A.Z and both histone marks. These results highlight the manifold functions of the histone variant FfH2A.Z in the phytopathogen F. fujikuroi, which are distinct regarding gene transcription and crosstalk with the two prominent histone marks H3K27me3 and H3K4me3, as proposed for other model organisms.
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Affiliation(s)
- Anna K Atanasoff-Kardjalieff
- Department of Applied Genetics and Cell Biology, Institute of Microbial Genetics, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz Strasse 24, Tulln an der Donau, 3430, Austria
| | - Harald Berger
- Department of Applied Genetics and Cell Biology, Institute of Microbial Genetics, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz Strasse 24, Tulln an der Donau, 3430, Austria
| | - Katharina Steinert
- Institute of Food Chemistry, University of Münster, Corrensstraße 45, 48149, Münster, Germany
| | - Slavica Janevska
- (Epi-)Genetic Regulation of Fungal Virulence, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute, 07745, Jena, Germany
| | - Nadia Ponts
- INRAE, UR1264 Mycology and Food Safety (MycSA), Villenave d'Ornon, 33882, France
| | - Hans-Ulrich Humpf
- Institute of Food Chemistry, University of Münster, Corrensstraße 45, 48149, Münster, Germany
| | - Svetlana Kalinina
- Institute of Food Chemistry, University of Münster, Corrensstraße 45, 48149, Münster, Germany
| | - Lena Studt-Reinhold
- Department of Applied Genetics and Cell Biology, Institute of Microbial Genetics, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz Strasse 24, Tulln an der Donau, 3430, Austria.
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4
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Maini Rekdal V, van der Luijt CRB, Chen Y, Kakumanu R, Baidoo EEK, Petzold CJ, Cruz-Morales P, Keasling JD. Edible mycelium bioengineered for enhanced nutritional value and sensory appeal using a modular synthetic biology toolkit. Nat Commun 2024; 15:2099. [PMID: 38485948 PMCID: PMC10940619 DOI: 10.1038/s41467-024-46314-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 02/21/2024] [Indexed: 03/18/2024] Open
Abstract
Filamentous fungi are critical in the transition to a more sustainable food system. While genetic modification of these organisms has promise for enhancing the nutritional value, sensory appeal, and scalability of fungal foods, genetic tools and demonstrated use cases for bioengineered food production by edible strains are lacking. Here, we develop a modular synthetic biology toolkit for Aspergillus oryzae, an edible fungus used in fermented foods, protein production, and meat alternatives. Our toolkit includes a CRISPR-Cas9 method for gene integration, neutral loci, and tunable promoters. We use these tools to elevate intracellular levels of the nutraceutical ergothioneine and the flavor-and color molecule heme in the edible biomass. The strain overproducing heme is red in color and is readily formulated into imitation meat patties with minimal processing. These findings highlight the promise of synthetic biology to enhance fungal foods and provide useful genetic tools for applications in food production and beyond.
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Affiliation(s)
- Vayu Maini Rekdal
- Department of Bioengineering, University of California, Berkeley, CA, 94720, USA
- Miller Institute for Basic Research in Science, University of California, Berkeley, CA, 94720, USA
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
| | - Casper R B van der Luijt
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
- Department of Food Science, University of Copenhagen, 1958, Frederiksberg, Denmark
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, CA, 94720, USA
| | - Yan Chen
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, CA, 94720, USA
| | - Ramu Kakumanu
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, CA, 94720, USA
| | - Edward E K Baidoo
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, CA, 94720, USA
| | - Christopher J Petzold
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, CA, 94720, USA
| | - Pablo Cruz-Morales
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
| | - Jay D Keasling
- Department of Bioengineering, University of California, Berkeley, CA, 94720, USA.
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark.
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, CA, 94720, USA.
- California Institute of Quantitative Biosciences (QB3), University of California, Berkeley, CA, 94720, USA.
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA.
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5
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Yang D, Xu Y, Mo L, Shi M, Wu N, Lu L, Xue F, Xu Q, Zhang C. Enhancing l-Malic Acid Production in Aspergillus niger via Natural Activation of sthA Gene Expression. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:4869-4879. [PMID: 38407053 DOI: 10.1021/acs.jafc.3c09321] [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: 02/27/2024]
Abstract
The efficient production of l-malic acid using Aspergillus niger requires overcoming challenges in synthesis efficiency and excessive byproduct buildup. This study addresses these hurdles, improving the activity of NADH-dependent malate dehydrogenase (Mdh) in the early stages of the fermentation process. By employing a constitutive promoter to express the Escherichia coli sthA responsible for the transfer of reducing equivalents between NAD(H) and NADP(H) in A. niger, the l-malic acid production was significantly elevated. However, this resulted in conidiation defects of A. niger, limiting industrial viability. To mitigate this, we discovered and utilized the PmfsA promoter, enabling the specific expression of sthA during the fermentation stage. This conditional expression strain showed similar phenotypes to its parent strain while exhibiting exceptional performance in a 5 L fermenter. Notably, it achieved a 65.5% increase in productivity, reduced fermentation cycle by 1.5 days, and lowered succinic acid by 76.2%. This work marks a promising advancement in industrial l-malic acid synthesis via biological fermentation, showcasing the potential of synthetic biology in A. niger for broader applications.
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Affiliation(s)
- Dongdong Yang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Yingyan Xu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Li Mo
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Man Shi
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Na Wu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Ling Lu
- College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Feng Xue
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Qing Xu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Chi Zhang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
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6
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Studt-Reinhold L, Atanasoff-Kardjalieff AK, Berger H, Petersen C, Bachleitner S, Sulyok M, Fischle A, Humpf HU, Kalinina S, Søndergaard TE. H3K27me3 is vital for fungal development and secondary metabolite gene silencing, and substitutes for the loss of H3K9me3 in the plant pathogen Fusarium proliferatum. PLoS Genet 2024; 20:e1011075. [PMID: 38166117 PMCID: PMC10786395 DOI: 10.1371/journal.pgen.1011075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 01/12/2024] [Accepted: 11/20/2023] [Indexed: 01/04/2024] Open
Abstract
Facultative heterochromatin marked by histone H3 lysine 27 trimethylation (H3K27me3) is an important regulatory layer involved in secondary metabolite (SM) gene silencing and crucial for fungal development in the genus Fusarium. While this histone mark is essential in some (e.g., the rice pathogen Fusarium fujikuroi), it appears dispensable in other fusaria. Here, we show that deletion of FpKMT6 is detrimental but not lethal in the plant pathogen Fusarium proliferatum, a member of the Fusarium fujikuroi species complex (FFSC). Loss of FpKmt6 results in aberrant growth, and expression of a large set of previously H3K27me3-silenced genes is accompanied by increased H3K27 acetylation (H3K27ac) and an altered H3K36me3 pattern. Next, H3K9me3 patterns are affected in Δfpkmt6, indicating crosstalk between both heterochromatic marks that became even more obvious in a strain deleted for FpKMT1 encoding the H3K9-specific histone methyltransferase. In Δfpkmt1, all H3K9me3 marks present in the wild-type strain are replaced by H3K27me3, a finding that may explain the subtle phenotype of the Δfpkmt1 strain which stands in marked contrast to other filamentous fungi. A large proportion of SM-encoding genes is allocated with H3K27me3 in the wild-type strain and loss of H3K27me3 results in elevated expression of 49% of them. Interestingly, genes involved in the biosynthesis of the phytohormones gibberellins (GA) are among the most upregulated genes in Δfpkmt6. Although several FFSC members harbor GA biosynthetic genes, its production is largely restricted to F. fujikuroi, possibly outlining the distinct lifestyles of these notorious plant pathogens. We show that H3K27me3 is involved in GA gene silencing in F. proliferatum and at least one additional FFSC member, and thus, may serve as a regulatory layer for gene silencing under non-favoring conditions.
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Affiliation(s)
- Lena Studt-Reinhold
- University of Natural Resources and Life Sciences, Vienna, Department of Applied Genetics and Cell Biology, Institute of Microbial Genetics, Tulln an der Donau, Austria
| | - Anna K. Atanasoff-Kardjalieff
- University of Natural Resources and Life Sciences, Vienna, Department of Applied Genetics and Cell Biology, Institute of Microbial Genetics, Tulln an der Donau, Austria
| | - Harald Berger
- University of Natural Resources and Life Sciences, Vienna, Department of Applied Genetics and Cell Biology, Institute of Microbial Genetics, Tulln an der Donau, Austria
| | - Celine Petersen
- Aalborg University, Department of Chemistry and Bioscience, Aalborg, Denmark
| | - Simone Bachleitner
- University of Natural Resources and Life Sciences, Vienna, Department of Applied Genetics and Cell Biology, Institute of Microbial Genetics, Tulln an der Donau, Austria
| | - Michael Sulyok
- University of Natural Resources and Life Sciences, Vienna, Department of Agrobiotechnology, Institute of Bioanalytics and Agro-Metabolomics, Tulln an der Donau, Austria
| | - Alica Fischle
- University of Münster, Institute of Food Chemistry, Münster, Germany
| | - Hans-Ulrich Humpf
- University of Münster, Institute of Food Chemistry, Münster, Germany
| | - Svetlana Kalinina
- University of Münster, Institute of Food Chemistry, Münster, Germany
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7
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Xie J, Rybak JM, Martin-Vicente A, Guruceaga X, Thorn HI, Nywening AV, Ge W, Parker JE, Kelly SL, Rogers PD, Fortwendel JR. The sterol C-24 methyltransferase encoding gene, erg6, is essential for viability of Aspergillus species. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.08.552489. [PMID: 37609350 PMCID: PMC10441335 DOI: 10.1101/2023.08.08.552489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Ergosterol is a critical component of fungal plasma membranes. Although many currently available antifungal compounds target the ergosterol biosynthesis pathway for antifungal effect, current knowledge regarding ergosterol synthesis remains incomplete for filamentous fungal pathogens like Aspergillus fumigatus. Here, we show for the first time that the lipid droplet-associated sterol C-24 methyltransferase, Erg6, is essential for A. fumigatus viability. We further show that this essentiality extends to additional Aspergillus species, including A. lentulus, A. terreus, and A. nidulans. Neither the overexpression of a putative erg6 paralog, smt1, nor the exogenous addition of ergosterol could rescue erg6 deficiency. Importantly, Erg6 downregulation results in a dramatic decrease in ergosterol and accumulation in lanosterol and is further characterized by diminished sterol-rich plasma membrane domains (SRDs) at hyphal tips. Unexpectedly, erg6 repressed strains demonstrate wild-type susceptibility against the ergosterol-active triazole and polyene antifungals. Finally, repressing erg6 expression reduced fungal burden accumulation in a murine model of invasive aspergillosis. Taken together, our studies suggest that Erg6, which shows little homology to mammalian proteins, is potentially an attractive antifungal drug target for therapy of Aspergillus infections.
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Affiliation(s)
- Jinhong Xie
- Graduate Program in Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN USA
| | - Jeffrey M. Rybak
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Adela Martin-Vicente
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN USA
| | - Xabier Guruceaga
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN USA
| | - Harrison I. Thorn
- Graduate Program in Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN USA
| | - Ashley V. Nywening
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN USA
- Integrated Program in Biomedical Sciences, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Microbiology, Immunology, and Biochemistry, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Wenbo Ge
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN USA
| | - Josie E. Parker
- Molecular Biosciences Division, School of Biosciences, Cardiff University, Cardiff, Wales, UK
| | - Steven L. Kelly
- Institute of Life Science, Swansea University Medical School, Swansea, Wales, UK
| | - P. David Rogers
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Jarrod R. Fortwendel
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN USA
- Department of Microbiology, Immunology, and Biochemistry, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
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8
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Cairns TC, de Kanter T, Zheng XZ, Zheng P, Sun J, Meyer V. Regression modelling of conditional morphogene expression links and quantifies the impact of growth rate, fitness and macromorphology with protein secretion in Aspergillus niger. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:95. [PMID: 37268954 DOI: 10.1186/s13068-023-02345-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 05/18/2023] [Indexed: 06/04/2023]
Abstract
BACKGROUND Filamentous fungi are used as industrial cell factories to produce a diverse portfolio of proteins, organic acids, and secondary metabolites in submerged fermentation. Generating optimized strains for maximum product titres relies on a complex interplay of molecular, cellular, morphological, and macromorphological factors that are not yet fully understood. RESULTS In this study, we generate six conditional expression mutants in the protein producing ascomycete Aspergillus niger and use them as tools to reverse engineer factors which impact total secreted protein during submerged growth. By harnessing gene coexpression network data, we bioinformatically predicted six morphology and productivity associated 'morphogenes', and placed them under control of a conditional Tet-on gene switch using CRISPR-Cas genome editing. Strains were phenotypically screened on solid and liquid media following titration of morphogene expression, generating quantitative measurements of growth rate, filamentous morphology, response to various abiotic perturbations, Euclidean parameters of submerged macromorphologies, and total secreted protein. These data were built into a multiple linear regression model, which identified radial growth rate and fitness under heat stress as positively correlated with protein titres. In contrast, diameter of submerged pellets and cell wall integrity were negatively associated with productivity. Remarkably, our model predicts over 60% of variation in A. niger secreted protein titres is dependent on these four variables, suggesting that they play crucial roles in productivity and are high priority processes to be targeted in future engineering programs. Additionally, this study suggests A. niger dlpA and crzA genes are promising new leads for enhancing protein titres during fermentation. CONCLUSIONS Taken together this study has identified several potential genetic leads for maximizing protein titres, delivered a suite of chassis strains with user controllable macromorphologies during pilot fermentation studies, and has quantified four crucial factors which impact secreted protein titres in A. niger.
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Affiliation(s)
- Timothy C Cairns
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße Des 17. Juni 135, 10623, Berlin, Germany.
| | - Tom de Kanter
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße Des 17. Juni 135, 10623, Berlin, Germany
| | - Xiaomei Z Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Ping Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Jibin Sun
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Vera Meyer
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße Des 17. Juni 135, 10623, Berlin, Germany.
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9
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van Rhijn N, Zhao C, Al-Furaji N, Storer I, Valero C, Gago S, Chown H, Baldin C, Fortune-Grant R, Shuraym HB, Ivanova L, Kniemeyer O, Krüger T, Bignell E, Goldman G, Amich J, Delneri D, Bowyer P, Brakhage A, Haas H, Bromley M. Functional analysis of the Aspergillus fumigatus kinome reveals a DYRK kinase involved in septal plugging is a novel antifungal drug target. RESEARCH SQUARE 2023:rs.3.rs-2960526. [PMID: 37398159 PMCID: PMC10312919 DOI: 10.21203/rs.3.rs-2960526/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
More than 10 million people suffer from lung diseases caused by the pathogenic fungus Aspergillus fumigatus. The azole class of antifungals represent first line therapeutics for most of these infections however resistance is rising. Identification of novel antifungal targets that, when inhibited, synergise with the azoles will aid the development of agents that can improve therapeutic outcomes and supress the emergence of resistance. As part of the A. fumigatus genome-wide knockout program (COFUN), we have completed the generation of a library that consists of 120 genetically barcoded null mutants in genes that encode the protein kinase cohort of A. fumigatus. We have employed a competitive fitness profiling approach (Bar-Seq), to identify targets which when deleted result in hypersensitivity to the azoles and fitness defects in a murine host. The most promising candidate from our screen is a previously uncharacterised DYRK kinase orthologous to Yak1 of Candida albicans, a TOR signalling pathway kinase involved in modulation of stress responsive transcriptional regulators. Here we show that the orthologue YakA has been repurposed in A. fumigatus to regulate blocking of the septal pore upon exposure to stress via phosphorylation of the Woronin body tethering protein Lah. Loss of YakA function reduces the ability of A. fumigatus to penetrate solid media and impacts growth in murine lung tissue. We also show that 1-ethoxycarbonyl-beta-carboline (1-ECBC), a compound previously shown to inhibit Yak1 in C. albicans prevents stress mediated septal spore blocking and synergises with the azoles to inhibit A. fumigatus growth.
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Affiliation(s)
| | - Can Zhao
- Manchester Fungal Infection Group
| | | | | | | | | | | | | | | | | | - Lia Ivanova
- Leibniz Institute for Natural Product Research and Infection Biology
| | - Olaf Kniemeyer
- Leibniz Institute for Natural Product Research and Infection Biology
| | - Thomas Krüger
- Leibniz Institute for Natural Product Research and Infection Biology
| | | | - Gustavo Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Bloco Q, Universidade de São Paulo
| | | | | | | | - Axel Brakhage
- Leibniz Institute for Natural Product Research and Infection Biology - University of Jena
| | - Hubertus Haas
- Institute of Molecular Biology/Biocenter, Innsbruck Medical University
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10
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Unlocking the magic in mycelium: Using synthetic biology to optimize filamentous fungi for biomanufacturing and sustainability. Mater Today Bio 2023; 19:100560. [PMID: 36756210 PMCID: PMC9900623 DOI: 10.1016/j.mtbio.2023.100560] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 01/22/2023] Open
Abstract
Filamentous fungi drive carbon and nutrient cycling across our global ecosystems, through its interactions with growing and decaying flora and their constituent microbiomes. The remarkable metabolic diversity, secretion ability, and fiber-like mycelial structure that have evolved in filamentous fungi have been increasingly exploited in commercial operations. The industrial potential of mycelial fermentation ranges from the discovery and bioproduction of enzymes and bioactive compounds, the decarbonization of food and material production, to environmental remediation and enhanced agricultural production. Despite its fundamental impact in ecology and biotechnology, molds and mushrooms have not, to-date, significantly intersected with synthetic biology in ways comparable to other industrial cell factories (e.g. Escherichia coli,Saccharomyces cerevisiae, and Komagataella phaffii). In this review, we summarize a suite of synthetic biology and computational tools for the mining, engineering and optimization of filamentous fungi as a bioproduction chassis. A combination of methods across genetic engineering, mutagenesis, experimental evolution, and computational modeling can be used to address strain development bottlenecks in established and emerging industries. These include slow mycelium growth rate, low production yields, non-optimal growth in alternative feedstocks, and difficulties in downstream purification. In the scope of biomanufacturing, we then detail previous efforts in improving key bottlenecks by targeting protein processing and secretion pathways, hyphae morphogenesis, and transcriptional control. Bringing synthetic biology practices into the hidden world of molds and mushrooms will serve to expand the limited panel of host organisms that allow for commercially-feasible and environmentally-sustainable bioproduction of enzymes, chemicals, therapeutics, foods, and materials of the future.
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11
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Baldin C, Kühbacher A, Merschak P, Wagener J, Gsaller F. Modular Inducible Multigene Expression System for Filamentous Fungi. Microbiol Spectr 2022; 10:e0367022. [PMID: 36350143 PMCID: PMC9769661 DOI: 10.1128/spectrum.03670-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 10/19/2022] [Indexed: 11/11/2022] Open
Abstract
Inducible promoters are indispensable elements when considering the possibility to modulate gene expression on demand. Desirable traits of conditional expression systems include their capacity for tight downregulation, high overexpression, and in some instances for fine-tuning, to achieve a desired product's stoichiometry. Although the number of inducible systems is slowly increasing, suitable promoters comprising these features are rare. To date, the concomitant use of multiple regulatable promoter platforms for controlled multigene expression has been poorly explored. This work provides pioneer work in the human pathogenic fungus Aspergillus fumigatus, wherein we investigated different inducible systems, elucidated three candidate promoters, and proved for the first time that up to three systems can be used simultaneously without interfering with each other. Proof of concept was obtained by conditionally expressing three antifungal drug targets within the ergosterol biosynthetic pathway under the control of the xylose-inducible PxylP system, the tetracycline-dependent Tet-On system, and the thiamine-repressible PthiA system. IMPORTANCE In recent years, inducible promoters have gained increasing interest for industrial or laboratory use and have become key instruments for protein expression, synthetic biology, and metabolic engineering. Constitutive, high-expressing promoters can be used to achieve high expression yields; however, the continuous overexpression of specific proteins can lead to an unpredictable metabolic burden. To prevent undesirable effects on the expression host's metabolism, the utilization of tunable systems that allow expression of a gene product on demand is indispensable. Here, we elucidated several excellent tunable promoter systems and verified that each can be independently induced in a single strain to ultimately develop a unique conditional multigene expression system. This highly efficient, modular toolbox has the potential to significantly advance applications in fundamental as well as applied research in which regulatable expression of several genes is a key requirement.
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Affiliation(s)
- Clara Baldin
- Institute of Molecular Biology, Biocenter Innsbruck, Medical University of Innsbruck, Innsbruck, Austria
| | - Alexander Kühbacher
- Institute of Molecular Biology, Biocenter Innsbruck, Medical University of Innsbruck, Innsbruck, Austria
| | - Petra Merschak
- Institute of Molecular Biology, Biocenter Innsbruck, Medical University of Innsbruck, Innsbruck, Austria
| | - Johannes Wagener
- Department of Clinical Microbiology, School of Medicine, Trinity College Dublin, The University of Dublin, Dublin, Ireland
| | - Fabio Gsaller
- Institute of Molecular Biology, Biocenter Innsbruck, Medical University of Innsbruck, Innsbruck, Austria
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12
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Antagonism of the Azoles to Olorofim and Cross-Resistance Are Governed by Linked Transcriptional Networks in Aspergillus fumigatus. mBio 2022; 13:e0221522. [PMID: 36286521 PMCID: PMC9765627 DOI: 10.1128/mbio.02215-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aspergillosis, in its various manifestations, is a major cause of morbidity and mortality. Very few classes of antifungal drugs have been approved for clinical use to treat these diseases and resistance to the first-line therapeutic class, the triazoles are increasing. A new class of antifungals that target pyrimidine biosynthesis, the orotomides, are currently in development with the first compound in this class, olorofim in late-stage clinical trials. In this study, we identified an antagonistic action of the triazoles on the action of olorofim. We showed that this antagonism was the result of an azole-induced upregulation of the pyrimidine biosynthesis pathway. Intriguingly, we showed that loss of function in the higher order transcription factor, HapB a member of the heterotrimeric HapB/C/E (CBC) complex or the regulator of nitrogen metabolic genes AreA, led to cross-resistance to both the azoles and olorofim, indicating that factors that govern resistance were under common regulatory control. However, the loss of azole-induced antagonism required decoupling of the pyrimidine biosynthetic pathway in a manner independent of the action of a single transcription factor. Our study provided evidence for complex transcriptional crosstalk between the pyrimidine and ergosterol biosynthetic pathways. IMPORTANCE Aspergillosis is a spectrum of diseases and a major cause of morbidity and mortality. To treat these diseases, there are a few classes of antifungal drugs approved for clinical use. Resistance to the first line treatment, the azoles, is increasing. The first antifungal, olorofim, which is in the novel class of orotomides, is currently in development. Here, we showed an antagonistic effect between the azoles and olorofim, which was a result of dysregulation of the pyrimidine pathway, the target of olorofim, and the ergosterol biosynthesis pathway, the target of the azoles.
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13
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Zheng X, Cairns T, Zheng P, Meyer V, Sun J. Protocol for gene characterization in Aspergillus niger using 5S rRNA-CRISPR-Cas9-mediated Tet-on inducible promoter exchange. STAR Protoc 2022; 3:101838. [PMID: 36595926 PMCID: PMC9678785 DOI: 10.1016/j.xpro.2022.101838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 09/29/2022] [Accepted: 10/18/2022] [Indexed: 11/19/2022] Open
Abstract
This protocol presents an efficient genetic strategy to investigate gene function in the fungus Aspergillus niger. We combined 5S rRNA-CRISPR-Cas9 technology with Tet-on gene switch to generate conditional-expression mutants via precisely replacing native promoter with inducible promoter. We describe the design and DNA preparation for sgRNAs and donor DNA. We then detail the steps for DNA co-transformation into A. niger protoplasts by PEG-mediated transformation, followed by homozygote isolation. Finally, we describe the genome verification and strain validation of the isolates. For complete details on the use and execution of this protocol, please refer to Zheng et al. (2019).1.
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Affiliation(s)
- Xiaomei Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China,University of Chinese Academy of Sciences, Beijing 100049, China,National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China,Corresponding author
| | - Timothy Cairns
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China,Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, 10263 Berlin, Germany
| | - Ping Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China,University of Chinese Academy of Sciences, Beijing 100049, China,National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China,Corresponding author
| | - Vera Meyer
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, 10263 Berlin, Germany
| | - Jibin Sun
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China,University of Chinese Academy of Sciences, Beijing 100049, China,National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China,Corresponding author
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14
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Qi J, Xiao X, Ouyang L, Yang C, Zhuang Y, Zhang L. Enhancement of fatty acid degradation pathway promoted glucoamylase synthesis in Aspergillus niger. Microb Cell Fact 2022; 21:238. [PMID: 36376878 PMCID: PMC9664828 DOI: 10.1186/s12934-022-01966-3] [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: 04/27/2022] [Accepted: 10/13/2022] [Indexed: 11/16/2022] Open
Abstract
Background Our recent multi-omics analyses of glucoamylase biosynthesis in Aspergillus niger (A. niger) suggested that lipid catabolism was significantly up-regulated during high-yield period under oxygen limitation. Since the catabolism of fatty acids can provide energy compounds such as ATP and important precursors such as acetyl-CoA, we speculated that enhancement of this pathway might be beneficial to glucoamylase overproduction. Results Based on previous transcriptome data, we selected and individually overexpressed five candidate genes involved in fatty acid degradation under the control of the Tet-on gene switch in A. niger. Overexpression of the fadE, fadA and cyp genes increased the final specific enzyme activity and total secreted protein on shake flask by 21.3 ~ 31.3% and 16.0 ~ 24.2%, respectively. And a better inducible effect by doxycycline was obtained from early logarithmic growth phase (18 h) than stationary phase (42 h). Similar with flask-level results, the glucoamylase content and total extracellular protein in engineered strains OE-fadE (overexpressing fadE) and OE-fadA (overexpressing fadA) on maltose-limited chemostat cultivation were improved by 31.2 ~ 34.1% and 35.1 ~ 38.8% compared to parental strain B36. Meanwhile, intracellular free fatty acids were correspondingly decreased by 41.6 ~ 44.6%. The metabolomic analysis demonstrated intracellular amino acids pools increased 24.86% and 18.49% in two engineered strains OE-fadE and OE-fadA compared to B36. Flux simulation revealed that increased ATP, acetyl-CoA and NADH was supplied into TCA cycle to improve amino acids synthesis for glucoamylase overproduction. Conclusion This study suggested for the first time that glucoamylase production was significantly improved in A. niger by overexpression of genes fadE and fadA involved in fatty acids degradation pathway. Harnessing the intracellular fatty acids could be a strategy to improve enzyme production in Aspergillus niger cell factory. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-022-01966-3.
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15
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Mózsik L, Iacovelli R, Bovenberg RAL, Driessen AJM. Transcriptional Activation of Biosynthetic Gene Clusters in Filamentous Fungi. Front Bioeng Biotechnol 2022; 10:901037. [PMID: 35910033 PMCID: PMC9335490 DOI: 10.3389/fbioe.2022.901037] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 06/17/2022] [Indexed: 11/13/2022] Open
Abstract
Filamentous fungi are highly productive cell factories, many of which are industrial producers of enzymes, organic acids, and secondary metabolites. The increasing number of sequenced fungal genomes revealed a vast and unexplored biosynthetic potential in the form of transcriptionally silent secondary metabolite biosynthetic gene clusters (BGCs). Various strategies have been carried out to explore and mine this untapped source of bioactive molecules, and with the advent of synthetic biology, novel applications, and tools have been developed for filamentous fungi. Here we summarize approaches aiming for the expression of endogenous or exogenous natural product BGCs, including synthetic transcription factors, assembly of artificial transcription units, gene cluster refactoring, fungal shuttle vectors, and platform strains.
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Affiliation(s)
- László Mózsik
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Riccardo Iacovelli
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Roel A. L. Bovenberg
- DSM Biotechnology Center, Delft, Netherlands
- Department of Synthetic Biology and Cell Engineering, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Arnold J. M. Driessen
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
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16
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Evaluation of Aspergillus niger Six Constitutive Strong Promoters by Fluorescent-Auxotrophic Selection Coupled with Flow Cytometry: A Case for Citric Acid Production. J Fungi (Basel) 2022; 8:jof8060568. [PMID: 35736051 PMCID: PMC9224621 DOI: 10.3390/jof8060568] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/19/2022] [Accepted: 05/24/2022] [Indexed: 02/05/2023] Open
Abstract
Aspergillus niger is an important industrial workhorse for the biomanufacturing of organic acids, proteins, etc. Well-controlled genetic regulatory elements, including promoters, are vital for strain engineering, but available strong promoters for A. niger are limited. Herein, to efficiently assess promoters, we developed an accurate and intuitive fluorescent-auxotrophic selection workflow based on mCherry, pyrG, CRISPR/Cas9 system, and flow cytometry. With this workflow, we characterized six endogenous constitutive promoters in A. niger. The endogenous glyceraldehyde-3-phosphate dehydrogenase promoter PgpdAg showed a 2.28-fold increase in promoter activity compared with the most frequently used strong promoter PgpdAd from A. nidulans. Six predicted conserved motifs, including the gpdA-box, were verified to be essential for the PgpdAg activity. To demonstrate its application, the promoter PgpdAg was used for enhancing the expression of citrate exporter cexA in a citric acid-producing isolate D353.8. Compared with the cexA controlled by PgpdAd, the transcription level of the cexA gene driven by PgpdAg increased by 2.19-fold, which is consistent with the promoter activity assessment. Moreover, following cexA overexpression, several genes involved in carbohydrate transport and metabolism were synergically upregulated, resulting in up to a 2.48-fold increase in citric acid titer compared with that of the parent strain. This study provides an intuitive workflow to speed up the quantitative evaluation of A. niger promoters and strong constitutive promoters for fungal cell factory construction and strain engineering.
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17
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Sun WW, Li CY, Chiang YM, Lin TS, Warren S, Chang FR, Wang CCC. Characterization of a silent azaphilone biosynthesis gene cluster in Aspergillus terreus NIH 2624. Fungal Genet Biol 2022; 160:103694. [PMID: 35398258 PMCID: PMC9701353 DOI: 10.1016/j.fgb.2022.103694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 03/04/2022] [Accepted: 04/03/2022] [Indexed: 11/28/2022]
Abstract
Filamentous fungal secondary metabolites are an important source of bioactive components. Genome sequencing ofAspergillus terreusrevealed many silent secondary metabolite biosynthetic gene clusters presumed to be involved in producing secondary metabolites. Activation of silent gene clusters through overexpressing a pathway-specific regulator is an effective avenue for discovering novel fungal secondary metabolites. Replacement of the native promoter of the pathway-specific activator with the inducible Tet-on system to activate thetazpathway led to the discovery of a series of azaphilone secondary metabolites, among which azaterrilone A (1) was purified and identified for the first time. Genetic deletion of core PKS genes and transcriptional analysis further characterized thetazgene cluster to consist of 16 genes with the NR-PKS and the HR-PKS collaborating in a convergent mode. Based on the putative gene functions and the characterized compounds structural information, a biosynthetic pathway of azaterrilone A (1) was proposed.
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Affiliation(s)
- Wei-Wen Sun
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, School of Pharmacy, 1985 Zonal Avenue, Los Angeles, CA 90089, USA
| | - Chi-Ying Li
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, School of Pharmacy, 1985 Zonal Avenue, Los Angeles, CA 90089, USA
| | - Yi-Ming Chiang
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, School of Pharmacy, 1985 Zonal Avenue, Los Angeles, CA 90089, USA; Graduate Institute of Pharmaceutical Science, Chia Nan University of Pharmacy and Science, Tainan 71710, Taiwan
| | - Tzu-Shyang Lin
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, School of Pharmacy, 1985 Zonal Avenue, Los Angeles, CA 90089, USA
| | - Shauna Warren
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, School of Pharmacy, 1985 Zonal Avenue, Los Angeles, CA 90089, USA
| | - Fang-Rong Chang
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Clay C C Wang
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, School of Pharmacy, 1985 Zonal Avenue, Los Angeles, CA 90089, USA; Department of Chemistry, University of Southern California, College of Letters, Arts, and Sciences, Los Angeles, CA 90089, USA.
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18
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Zheng X, Cairns TC, Ni X, Zhang L, Zhai H, Meyer V, Zheng P, Sun J. Comprehensively dissecting the hub regulation of PkaC on high-productivity and pellet macromorphology in citric acid producing Aspergillus niger. Microb Biotechnol 2022; 15:1867-1882. [PMID: 35213792 PMCID: PMC9151341 DOI: 10.1111/1751-7915.14020] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 01/20/2022] [Accepted: 02/08/2022] [Indexed: 12/12/2022] Open
Abstract
Aspergillus niger, an important industrial workhorse for citric acid production, is characterized by polar hyphal growth with complex pelleted, clumped or dispersed macromorphologies in submerged culture. Although organic acid titres are dramatically impacted by these growth types, studies that assess productivity and macromorphological changes are limited. Herein, we functionally analysed the role of the protein kinase A (PKA)/cyclic adenosine monophosphate (cAMP) signalling cascade during fermentation by disrupting and conditionally expressing the pkaC gene. pkaC played multiple roles during hyphal, colony and conidiophore growth. By overexpressing pkaC, we could concomitantly modify hyphal growth at the pellet surface and improve citric acid titres up to 1.87‐fold. By quantitatively analysing hundreds of pellets during pilot fermentation experiments, we provide the first comprehensive correlation between A. niger pellet surface morphology and citric acid production. Finally, by intracellular metabolomics analysis and weighted gene coexpression network analysis (WGCNA) following titration of pkaC expression, we unveil the metabolomic and transcriptomic basis underpin hyperproductivity and pellet growth. Taken together, this study confirms pkaC as hub regulator linking submerged macromorphology and citric acid production and provides high‐priority genetic leads for future strain engineering programmes.
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Affiliation(s)
- Xiaomei Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin, 300308, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Timothy C Cairns
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin, 300308, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,Institute of Biotechnology, Chair of Applied and Molecular Microbiology, Technische Universität Berlin, Berlin, 13355, Germany
| | - Xiaomei Ni
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin, 300308, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Lihui Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin, 300308, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Huanhuan Zhai
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin, 300308, China
| | - Vera Meyer
- Institute of Biotechnology, Chair of Applied and Molecular Microbiology, Technische Universität Berlin, Berlin, 13355, Germany
| | - Ping Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin, 300308, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Jibin Sun
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin, 300308, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
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Cairns TC, Zheng X, Feurstein C, Zheng P, Sun J, Meyer V. A Library of Aspergillus niger Chassis Strains for Morphology Engineering Connects Strain Fitness and Filamentous Growth With Submerged Macromorphology. Front Bioeng Biotechnol 2022; 9:820088. [PMID: 35111742 PMCID: PMC8801610 DOI: 10.3389/fbioe.2021.820088] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/03/2021] [Indexed: 01/06/2023] Open
Abstract
Submerged fermentation using filamentous fungal cell factories is used to produce a diverse portfolio of useful molecules, including food, medicines, enzymes, and platform chemicals. Depending on strain background and abiotic culture conditions, different macromorphologies are formed during fermentation, ranging from dispersed hyphal fragments to approximately spherical pellets several millimetres in diameter. These macromorphologies are known to have a critical impact on product titres and rheological performance of the bioreactor. Pilot productivity screens in different macromorphological contexts is technically challenging, time consuming, and thus a significant limitation to achieving maximum product titres. To address this bottleneck, we developed a library of conditional expression mutants in the organic, protein, and secondary metabolite cell factory Aspergillus niger. Thirteen morphology-associated genes transcribed during fermentation were placed via CRISPR-Cas9 under control of a synthetic Tet-on gene switch. Quantitative analysis of submerged growth reveals that these strains have distinct and titratable macromorphologies for use as chassis during strain engineering programs. We also used this library as a tool to quantify how pellet formation is connected with strain fitness and filamentous growth. Using multiple linear regression modelling, we predict that pellet formation is dependent largely on strain fitness, whereas pellet Euclidian parameters depend on fitness and hyphal branching. Finally, we have shown that conditional expression of the putative kinase encoding gene pkh2 can decouple fitness, dry weight, pellet macromorphology, and culture heterogeneity. We hypothesize that further analysis of this gene product and the cell wall integrity pathway in which it is embedded will enable more precise engineering of A. niger macromorphology in future.
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Affiliation(s)
- Timothy C. Cairns
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
- *Correspondence: Timothy C. Cairns, ; Jibin Sun, ; Vera Meyer,
| | - Xiaomei Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- University of Chinese Academy of Sciences, Beijing, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Claudia Feurstein
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Ping Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- University of Chinese Academy of Sciences, Beijing, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Jibin Sun
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- University of Chinese Academy of Sciences, Beijing, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
- *Correspondence: Timothy C. Cairns, ; Jibin Sun, ; Vera Meyer,
| | - Vera Meyer
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
- *Correspondence: Timothy C. Cairns, ; Jibin Sun, ; Vera Meyer,
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20
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Mózsik L, Pohl C, Meyer V, Bovenberg RAL, Nygård Y, Driessen AJM. Modular Synthetic Biology Toolkit for Filamentous Fungi. ACS Synth Biol 2021; 10:2850-2861. [PMID: 34726388 PMCID: PMC8609570 DOI: 10.1021/acssynbio.1c00260] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
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Filamentous fungi
are highly productive cell factories, often used
in industry for the production of enzymes and small bioactive compounds.
Recent years have seen an increasing number of synthetic-biology-based
applications in fungi, emphasizing the need for a synthetic biology
toolkit for these organisms. Here we present a collection of 96 genetic
parts, characterized in Penicillium or Aspergillus species, that are
compatible and interchangeable with the Modular Cloning system. The
toolkit contains natural and synthetic promoters (constitutive and
inducible), terminators, fluorescent reporters, and selection markers.
Furthermore, there are regulatory and DNA-binding domains of transcriptional
regulators and components for implementing different CRISPR-based
technologies. Genetic parts can be assembled into complex multipartite
assemblies and delivered through genomic integration or expressed
from an AMA1-sequence-based, fungal-replicating shuttle vector. With
this toolkit, synthetic transcription units with established promoters,
fusion proteins, or synthetic transcriptional regulation devices can
be more rapidly assembled in a standardized and modular manner for
novel fungal cell factories.
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Affiliation(s)
- László Mózsik
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Carsten Pohl
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, 10623 Berlin, Germany
| | - Vera Meyer
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, 10623 Berlin, Germany
| | - Roel A. L. Bovenberg
- DSM Biotechnology Center, 2613 AX Delft, The Netherlands
- Synthetic Biology and Cell Engineering, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Yvonne Nygård
- Department of Biology and Biological Engineering, Division of Industrial Biotechnology, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Arnold J. M. Driessen
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands
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21
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Beyond the Biosynthetic Gene Cluster Paradigm: Genome-Wide Coexpression Networks Connect Clustered and Unclustered Transcription Factors to Secondary Metabolic Pathways. Microbiol Spectr 2021; 9:e0089821. [PMID: 34523946 PMCID: PMC8557879 DOI: 10.1128/spectrum.00898-21] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Fungal secondary metabolites are widely used as therapeutics and are vital components of drug discovery programs. A major challenge hindering discovery of novel secondary metabolites is that the underlying pathways involved in their biosynthesis are transcriptionally silent under typical laboratory growth conditions, making it difficult to identify the transcriptional networks that they are embedded in. Furthermore, while the genes participating in secondary metabolic pathways are typically found in contiguous clusters on the genome, known as biosynthetic gene clusters (BGCs), this is not always the case, especially for global and pathway-specific regulators of pathways’ activities. To address these challenges, we used 283 genome-wide gene expression data sets of the ascomycete cell factory Aspergillus niger generated during growth under 155 different conditions to construct two gene coexpression networks based on Spearman’s correlation coefficients (SCCs) and on mutual rank-transformed Pearson’s correlation coefficients (MR-PCCs). By mining these networks, we predicted six transcription factors, named MjkA to MjkF, to regulate secondary metabolism in A. niger. Overexpression of each transcription factor using the Tet-On cassette modulated the production of multiple secondary metabolites. We found that the SCC and MR-PCC approaches complemented each other, enabling the delineation of putative global (SCC) and pathway-specific (MR-PCC) transcription factors. These results highlight the potential of coexpression network approaches to identify and activate fungal secondary metabolic pathways and their products. More broadly, we argue that drug discovery programs in fungi should move beyond the BGC paradigm and focus on understanding the global regulatory networks in which secondary metabolic pathways are embedded. IMPORTANCE There is an urgent need for novel bioactive molecules in both agriculture and medicine. The genomes of fungi are thought to contain vast numbers of metabolic pathways involved in the biosynthesis of secondary metabolites with diverse bioactivities. Because these metabolites are biosynthesized only under specific conditions, the vast majority of the fungal pharmacopeia awaits discovery. To discover the genetic networks that regulate the activity of secondary metabolites, we examined the genome-wide profiles of gene activity of the cell factory Aspergillus niger across hundreds of conditions. By constructing global networks that link genes with similar activities across conditions, we identified six putative global and pathway-specific regulators of secondary metabolite biosynthesis. Our study shows that elucidating the behavior of the genetic networks of fungi under diverse conditions harbors enormous promise for understanding fungal secondary metabolism, which ultimately may lead to novel drug candidates.
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22
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Meyer V, Cairns T, Barthel L, King R, Kunz P, Schmideder S, Müller H, Briesen H, Dinius A, Krull R. Understanding and controlling filamentous growth of fungal cell factories: novel tools and opportunities for targeted morphology engineering. Fungal Biol Biotechnol 2021; 8:8. [PMID: 34425914 PMCID: PMC8383395 DOI: 10.1186/s40694-021-00115-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 08/02/2021] [Indexed: 02/20/2023] Open
Abstract
Filamentous fungal cell factories are efficient producers of platform chemicals, proteins, enzymes and natural products. Stirred-tank bioreactors up to a scale of several hundred m³ are commonly used for their cultivation. Fungal hyphae self-assemble into various cellular macromorphologies ranging from dispersed mycelia, loose clumps, to compact pellets. Development of these macromorphologies is so far unpredictable but strongly impacts productivities of fungal bioprocesses. Depending on the strain and the desired product, the morphological forms vary, but no strain- or product-related correlations currently exist to improve
process understanding of fungal production systems. However, novel genomic, genetic, metabolic, imaging and modelling tools have recently been established that will provide fundamental new insights into filamentous fungal growth and how it is balanced with product formation. In this primer, these tools will be highlighted and their revolutionary impact on rational morphology engineering and bioprocess control will be discussed.
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Affiliation(s)
- Vera Meyer
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany.
| | - Timothy Cairns
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Lars Barthel
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Rudibert King
- Chair of Measurement and Control, Institute of Chemical and Process Engineering, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Philipp Kunz
- Chair of Measurement and Control, Institute of Chemical and Process Engineering, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Stefan Schmideder
- Chair of Process Systems Engineering, School of Life Sciences, Technical University of Munich, Gregor- Mendel-Str. 4, 85354, Freising, Germany
| | - Henri Müller
- Chair of Process Systems Engineering, School of Life Sciences, Technical University of Munich, Gregor- Mendel-Str. 4, 85354, Freising, Germany
| | - Heiko Briesen
- Chair of Process Systems Engineering, School of Life Sciences, Technical University of Munich, Gregor- Mendel-Str. 4, 85354, Freising, Germany
| | - Anna Dinius
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany.,Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Franz-Liszt-Str. 35a, 38106, Brunswick, Germany
| | - Rainer Krull
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany.,Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Franz-Liszt-Str. 35a, 38106, Brunswick, Germany
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23
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Something old, something new: challenges and developments in Aspergillus niger biotechnology. Essays Biochem 2021; 65:213-224. [PMID: 33955461 PMCID: PMC8314004 DOI: 10.1042/ebc20200139] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/17/2021] [Accepted: 03/19/2021] [Indexed: 12/12/2022]
Abstract
The filamentous ascomycete fungus Aspergillus niger is a prolific secretor of organic acids, proteins, enzymes and secondary metabolites. Throughout the last century, biotechnologists have developed A. niger into a multipurpose cell factory with a product portfolio worth billions of dollars each year. Recent technological advances, from genome editing to other molecular and omics tools, promise to revolutionize our understanding of A. niger biology, ultimately to increase efficiency of existing industrial applications or even to make entirely new products. However, various challenges to this biotechnological vision, many several decades old, still limit applications of this fungus. These include an inability to tightly control A. niger growth for optimal productivity, and a lack of high-throughput cultivation conditions for mutant screening. In this mini-review, we summarize the current state-of-the-art for A. niger biotechnology with special focus on organic acids (citric acid, malic acid, gluconic acid and itaconic acid), secreted proteins and secondary metabolites, and discuss how new technological developments can be applied to comprehensively address a variety of old and persistent challenges.
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24
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Exploration and characterization of hypoxia-inducible endogenous promoters in Aspergillus niger. Appl Microbiol Biotechnol 2021; 105:5529-5539. [PMID: 34254155 DOI: 10.1007/s00253-021-11417-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 05/25/2021] [Accepted: 05/29/2021] [Indexed: 12/13/2022]
Abstract
Aspergillus niger is widely used for the efficient production of organic acids and enzyme preparations. However, this organism lacks basic genetic elements for dynamic control, especially inducible promoters that can respond to specific environmental signals. Since these are desirable for better adaptation of fermentation to large-scale industrial production, herein, we have identified the two first hypoxia-inducible promoters in A. niger, PsrbB and PfhbA. Their performance under high or low oxygen conditions was monitored using two reporter proteins, green fluorescent protein (EGFP) and β-glucuronidase (GUS). For comparison, basal expression of the general strong promoter PgpdA was lower than PsrbB but higher than PfhbA. However, under hypoxia, both promoters showed higher expression than under hyperoxia, and these values were also higher than those observed for PgpdA. For PsrbB, strength under hypoxia was ~2-3 times higher than under hyperoxia (for PfhbA, 3-9 times higher) and ~2.5-5 times higher than for PgpdA (for PfhbA, 2-3 times higher). Promoter truncation analysis showed that the PsrbB fragment -1024 to -588 bp is the core region that determines hypoxia response. KEY POINTS: The first identification of two hypoxia-inducible promoters in A. niger is a promising tool for modulation of target genes under hypoxia. Two reporter genes revealed a different activity and responsiveness to hypoxia of PfhbA and PsrbB promoters, which is relevant for the development of dynamic metabolic regulation of A. niger fermentation. PsrbB promoter truncation and bioinformatics analysis is the foundation for further research.
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25
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Asemoloye MD, Marchisio MA, Gupta VK, Pecoraro L. Genome-based engineering of ligninolytic enzymes in fungi. Microb Cell Fact 2021; 20:20. [PMID: 33478513 PMCID: PMC7819241 DOI: 10.1186/s12934-021-01510-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/07/2021] [Indexed: 12/23/2022] Open
Abstract
Background Many fungi grow as saprobic organisms and obtain nutrients from a wide range of dead organic materials. Among saprobes, fungal species that grow on wood or in polluted environments have evolved prolific mechanisms for the production of degrading compounds, such as ligninolytic enzymes. These enzymes include arrays of intense redox-potential oxidoreductase, such as laccase, catalase, and peroxidases. The ability to produce ligninolytic enzymes makes a variety of fungal species suitable for application in many industries, including the production of biofuels and antibiotics, bioremediation, and biomedical application as biosensors. However, fungal ligninolytic enzymes are produced naturally in small quantities that may not meet the industrial or market demands. Over the last decade, combined synthetic biology and computational designs have yielded significant results in enhancing the synthesis of natural compounds in fungi. Main body of the abstract In this review, we gave insights into different protein engineering methods, including rational, semi-rational, and directed evolution approaches that have been employed to enhance the production of some important ligninolytic enzymes in fungi. We described the role of metabolic pathway engineering to optimize the synthesis of chemical compounds of interest in various fields. We highlighted synthetic biology novel techniques for biosynthetic gene cluster (BGC) activation in fungo and heterologous reconstruction of BGC in microbial cells. We also discussed in detail some recombinant ligninolytic enzymes that have been successfully enhanced and expressed in different heterologous hosts. Finally, we described recent advance in CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)-Cas (CRISPR associated) protein systems as the most promising biotechnology for large-scale production of ligninolytic enzymes. Short conclusion Aggregation, expression, and regulation of ligninolytic enzymes in fungi require very complex procedures with many interfering factors. Synthetic and computational biology strategies, as explained in this review, are powerful tools that can be combined to solve these puzzles. These integrated strategies can lead to the production of enzymes with special abilities, such as wide substrate specifications, thermo-stability, tolerance to long time storage, and stability in different substrate conditions, such as pH and nutrients.
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Affiliation(s)
- Michael Dare Asemoloye
- School of Pharmaceutical Science and Technology, Tianjin University, Nankai District, 92 Weijin Road, Tianjin, 300072, China
| | - Mario Andrea Marchisio
- School of Pharmaceutical Science and Technology, Tianjin University, Nankai District, 92 Weijin Road, Tianjin, 300072, China.
| | - Vijai Kumar Gupta
- Biorefining and Advanced Materials Research Center, Scotland's Rural College (SRUC), Kings Buildings, West Mains Road, Edinburgh, EH9 3JG, UK
| | - Lorenzo Pecoraro
- School of Pharmaceutical Science and Technology, Tianjin University, Nankai District, 92 Weijin Road, Tianjin, 300072, China.
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26
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Sui YF, Schütze T, Ouyang LM, Lu H, Liu P, Xiao X, Qi J, Zhuang YP, Meyer V. Engineering cofactor metabolism for improved protein and glucoamylase production in Aspergillus niger. Microb Cell Fact 2020; 19:198. [PMID: 33097040 PMCID: PMC7584080 DOI: 10.1186/s12934-020-01450-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 10/07/2020] [Indexed: 01/26/2023] Open
Abstract
Background Nicotinamide adenine dinucleotide phosphate (NADPH) is an important cofactor ensuring intracellular redox balance, anabolism and cell growth in all living systems. Our recent multi-omics analyses of glucoamylase (GlaA) biosynthesis in the filamentous fungal cell factory Aspergillus niger indicated that low availability of NADPH might be a limiting factor for GlaA overproduction. Results We thus employed the Design-Build-Test-Learn cycle for metabolic engineering to identify and prioritize effective cofactor engineering strategies for GlaA overproduction. Based on available metabolomics and 13C metabolic flux analysis data, we individually overexpressed seven predicted genes encoding NADPH generation enzymes under the control of the Tet-on gene switch in two A. niger recipient strains, one carrying a single and one carrying seven glaA gene copies, respectively, to test their individual effects on GlaA and total protein overproduction. Both strains were selected to understand if a strong pull towards glaA biosynthesis (seven gene copies) mandates a higher NADPH supply compared to the native condition (one gene copy). Detailed analysis of all 14 strains cultivated in shake flask cultures uncovered that overexpression of the gsdA gene (glucose 6-phosphate dehydrogenase), gndA gene (6-phosphogluconate dehydrogenase) and maeA gene (NADP-dependent malic enzyme) supported GlaA production on a subtle (10%) but significant level in the background strain carrying seven glaA gene copies. We thus performed maltose-limited chemostat cultures combining metabolome analysis for these three isolates to characterize metabolic-level fluctuations caused by cofactor engineering. In these cultures, overexpression of either the gndA or maeA gene increased the intracellular NADPH pool by 45% and 66%, and the yield of GlaA by 65% and 30%, respectively. In contrast, overexpression of the gsdA gene had a negative effect on both total protein and glucoamylase production. Conclusions This data suggests for the first time that increased NADPH availability can indeed underpin protein and especially GlaA production in strains where a strong pull towards GlaA biosynthesis exists. This data also indicates that the highest impact on GlaA production can be engineered on a genetic level by increasing the flux through the pentose phosphate pathway (gndA gene) followed by engineering the flux through the reverse TCA cycle (maeA gene). We thus propose that NADPH cofactor engineering is indeed a valid strategy for metabolic engineering of A. niger to improve GlaA production, a strategy which is certainly also applicable to the rational design of other microbial cell factories.![]()
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Affiliation(s)
- Yu-Fei Sui
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.,Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Tabea Schütze
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Li-Ming Ouyang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China
| | - Hongzhong Lu
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96, Gothenburg, Sweden
| | - Peng Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China
| | - Xianzun Xiao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China
| | - Jie Qi
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China
| | - Ying-Ping Zhuang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
| | - Vera Meyer
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany.
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27
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Targeting Methionine Synthase in a Fungal Pathogen Causes a Metabolic Imbalance That Impacts Cell Energetics, Growth, and Virulence. mBio 2020; 11:mBio.01985-20. [PMID: 33051366 PMCID: PMC7554668 DOI: 10.1128/mbio.01985-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Fungal pathogens are responsible for millions of life-threatening infections on an annual basis worldwide. The current repertoire of antifungal drugs is very limited and, worryingly, resistance has emerged and already become a serious threat to our capacity to treat fungal diseases. The first step to develop new drugs is often to identify molecular targets in the pathogen whose inhibition during infection can prevent its growth. However, the current models are not suitable to validate targets in established infections. Here, we have characterized the promising antifungal target methionine synthase in great detail, using the prominent fungal pathogen Aspergillus fumigatus as a model. We have uncovered the underlying reason for its essentiality and confirmed its druggability. Furthermore, we have optimized the use of a genetic system to show a beneficial effect of targeting methionine synthase in established infections. Therefore, we believe that antifungal drugs to target methionine synthase should be pursued and additionally, we provide a model that permits gaining information about the validity of antifungal targets in established infections. There is an urgent need to develop novel antifungals to tackle the threat fungal pathogens pose to human health. Here, we have performed a comprehensive characterization and validation of the promising target methionine synthase (MetH). We show that in Aspergillus fumigatus the absence of this enzymatic activity triggers a metabolic imbalance that causes a reduction in intracellular ATP, which prevents fungal growth even in the presence of methionine. Interestingly, growth can be recovered in the presence of certain metabolites, which shows that metH is a conditionally essential gene and consequently should be targeted in established infections for a more comprehensive validation. Accordingly, we have validated the use of the tetOFF genetic model in fungal research and improved its performance in vivo to achieve initial validation of targets in models of established infection. We show that repression of metH in growing hyphae halts growth in vitro, which translates into a beneficial effect when targeting established infections using this model in vivo. Finally, a structure-based virtual screening of methionine synthases reveals key differences between the human and fungal structures and unravels features in the fungal enzyme that can guide the design of novel specific inhibitors. Therefore, methionine synthase is a valuable target for the development of new antifungals.
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28
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Derntl C, Mach R, Mach-Aigner A. Application of the human estrogen receptor within a synthetic transcription factor in Trichoderma reesei. Fungal Biol Biotechnol 2020; 7:12. [PMID: 32765896 PMCID: PMC7396459 DOI: 10.1186/s40694-020-00102-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 07/17/2020] [Indexed: 12/28/2022] Open
Abstract
Background Synthetic gene expression systems offer a possibility for controllable and targeted induction of the expression of genes of interest, which is a fundamental technique necessary for basic research and industrial applications. The human estrogen receptor α contains a ligand binding domain that enforces dimerization and nuclear import upon binding of the inducer 17β-estradiol. In this study, we tested the potential of this ligand binding domain to be used in filamentous fungi as an auto-regulatory domain in a synthetic transcription factor. Results We constructed the synthetic transcription factor SynX by fusing the DNA-binding domain of Xyr1 (Xylanase Regulator 1), the transactivation domain of Ypr1 (Yellow Pigment Regulator 1), and the ligand binding domain of the human estrogen receptor α. SynX is able to strongly induce the gene expression of xylanases and an aldose reductase by addition of 17β-estradiol, but SynX does not induce gene expression of cellulases. Importantly, the induction of xylanase activities is mostly carbon source independent and can be fine-tuned by controlling the concentration of 17β-estradiol. Conclusion The ability of SynX to induce gene expression of xylanase encoding genes by addition of 17β-estradiol demonstrates that the ligand binding domain of the human estrogen receptor α works in filamentous fungi, and that it can be combined with a transactivation domain other than the commonly used transactivation domain of herpes simplex virion protein VP16.
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Affiliation(s)
- Christian Derntl
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060 Vienna, Austria
| | - Robert Mach
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060 Vienna, Austria
| | - Astrid Mach-Aigner
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060 Vienna, Austria
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29
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Binder J, Shadkchan Y, Osherov N, Krappmann S. The Essential Thioredoxin Reductase of the Human Pathogenic Mold Aspergillus fumigatus Is a Promising Antifungal Target. Front Microbiol 2020; 11:1383. [PMID: 32670238 PMCID: PMC7330004 DOI: 10.3389/fmicb.2020.01383] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 05/28/2020] [Indexed: 12/12/2022] Open
Abstract
The identification of cellular targets for antifungal compounds is a cornerstone for the development of novel antimycotics, for which a significant need exists due to increasing numbers of susceptible patients, emerging pathogens, and evolving resistance. For the human pathogenic mold Aspergillus fumigatus, the causative agent of the opportunistic disease aspergillosis, only a limited number of established targets and corresponding drugs are available. Among several targets that were postulated from a variety of experimental approaches, the conserved thioredoxin reductase (TrxR) activity encoded by the trxR gene was assessed in this study. Its essentiality could be confirmed following a conditional TetOFF promoter replacement strategy. Relevance of the trxR gene product for oxidative stress resistance was revealed and, most importantly, its requirement for full virulence of A. fumigatus in two different models of infection resembling invasive aspergillosis. Our findings complement the idea of targeting the reductase component of the fungal thioredoxin system for antifungal therapy.
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Affiliation(s)
- Jasmin Binder
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Yana Shadkchan
- Aspergillus and Antifungal Research Laboratory, Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Nir Osherov
- Aspergillus and Antifungal Research Laboratory, Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Sven Krappmann
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Medical Immunology Campus Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Erlangen Center of Infection Research, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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Sui YF, Ouyang LM, Schütze T, Cheng S, Meyer V, Zhuang YP. Comparative genomics of the aconidial Aspergillus niger strain LDM3 predicts genes associated with its high protein secretion capacity. Appl Microbiol Biotechnol 2020; 104:2623-2637. [DOI: 10.1007/s00253-020-10398-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 01/02/2020] [Accepted: 01/20/2020] [Indexed: 01/14/2023]
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31
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Deng H, Bai Y, Fan TP, Zheng X, Cai Y. Advanced strategy for metabolite exploration in filamentous fungi. Crit Rev Biotechnol 2020; 40:180-198. [PMID: 31906740 DOI: 10.1080/07388551.2019.1709798] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Filamentous fungi comprise an abundance of gene clusters that encode high-value metabolites, whereas affluent gene clusters remain silent during laboratory conditions. Complex cellular metabolism further limits these metabolite yields. Therefore, diverse strategies such as genetic engineering and chemical mutagenesis have been developed to activate these cryptic pathways and improve metabolite productivity. However, lower efficiencies of gene modifications and screen tools delayed the above processes. To address the above issues, this review describes an alternative design-construction evaluation optimization (DCEO) approach. The DCEO tool provides theoretical and practical principles to identify potential pathways, modify endogenous pathways, integrate exogenous pathways, and exploit novel pathways for their diverse metabolites and desirable productivities. This DCEO method also offers different tactics to balance the cellular metabolisms, facilitate the genetic engineering, and exploit the scalable metabolites in filamentous fungi.
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Affiliation(s)
- Huaxiang Deng
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China.,Center for Synthetic Biochemistry, Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technologies, Shenzhen, China
| | - Yajun Bai
- College of Life Sciences, Northwest University, Xi'an, Shanxi, China
| | - Tai-Ping Fan
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Xiaohui Zheng
- College of Life Sciences, Northwest University, Xi'an, Shanxi, China
| | - Yujie Cai
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
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32
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Nevalainen H. Strategies and Challenges for the Development of Industrial Enzymes Using Fungal Cell Factories. GRAND CHALLENGES IN FUNGAL BIOTECHNOLOGY 2020. [PMCID: PMC7123961 DOI: 10.1007/978-3-030-29541-7_7] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Industrial enzymes have been produced from microorganisms for more than a century. Today, a large share of enzyme products is manufactured using recombinant microorganisms. This chapter focuses on major industrial fungal species belonging to the ascomycetes like Aspergillus niger, A. oryzae, and Trichoderma reesei. Many of the commercially available recombinant enzymes are manufactured using fungi. Examples of fungal enzymes used in food products are described. The enzyme industry is to a large extent cost-driven, so the enzyme product needs to meet strict COGS (cost of goods sold) targets. Therefore, the cell factory must be very efficient to produce the enzyme in high titers and efficiently utilize raw materials. Secondly, it must be designed for a robust and generic fermentation process. When developing fungal hosts for enzyme production, several properties of the system need to be considered relating to efficiency of the cell factory, purity of the product, and safety of both the cell factory and the product. Purity is secured by engineering of the cell factory, and properties related to safety must also be engineered into the fungal host. The methods used for strain improvement are continuously being developed to increase yields and are described herein. More automation using precision tools for modification of the genome (i.e., CRISPR) and low-cost sequencing have vastly expanded the possibilities and enabled fast strain development. Using systems biology approaches, better understanding of cellular processes is now possible enabling advanced engineering of fungal cell factories. Surprisingly, a survey of innovation in the field revealed a decrease in the number of patent applications in recent years. Finally, the requirements for enzyme approval, especially in food and feed, have increased significantly worldwide in the last few years. A description of the regulatory landscape and its challenges in food and feed is included.
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Affiliation(s)
- Helena Nevalainen
- Department of Molecular Sciences, Macquarie University, Sydney, NSW Australia
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33
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Bidirectional histone-gene promoters in Aspergillus: characterization and application for multi-gene expression. Fungal Biol Biotechnol 2019; 6:24. [PMID: 31867115 PMCID: PMC6900853 DOI: 10.1186/s40694-019-0088-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 11/23/2019] [Indexed: 02/01/2023] Open
Abstract
Background Filamentous fungi are important producers of enzymes and bioactive secondary metabolites and are exploited for industrial purposes. Expression and characterization of biosynthetic pathways requires stable expression of multiple genes in the production host. Fungal promoters are indispensable for the accomplishment of this task, and libraries of promoters that show functionality across diverse fungal species facilitate synthetic biology approaches, pathway expression, and cell-factory construction. Results In this study, we characterized the intergenic region between the genes encoding histones H4.1 and H3, from five phylogenetically diverse species of Aspergillus, as bidirectional promoters (Ph4h3). By expression of the genes encoding fluorescent proteins mRFP1 and mCitrine, we show at the translational and transcriptional level that this region from diverse species is applicable as strong and constitutive bidirectional promoters in Aspergillus nidulans. Bioinformatic analysis showed that the divergent gene orientation of h4.1 and h3 appears maintained among fungi, and that the Ph4h3 display conserved DNA motifs among the investigated 85 Aspergilli. Two of the heterologous Ph4h3s were utilized for single-locus expression of four genes from the putative malformin producing pathway from Aspergillus brasiliensis in A. nidulans. Strikingly, heterologous expression of mlfA encoding the non-ribosomal peptide synthetase is sufficient for biosynthesis of malformins in A. nidulans, which indicates an iterative use of one adenylation domain in the enzyme. However, this resulted in highly stressed colonies, which was reverted to a healthy phenotype by co-expressing the residual four genes from the putative biosynthetic gene cluster. Conclusions Our study has documented that Ph4h3 is a strong constitutive bidirectional promoter and a valuable new addition to the genetic toolbox of at least the genus Aspergillus.
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Bauer I, Misslinger M, Shadkchan Y, Dietl AM, Petzer V, Orasch T, Abt B, Graessle S, Osherov N, Haas H. The Lysine Deacetylase RpdA Is Essential for Virulence in Aspergillus fumigatus. Front Microbiol 2019; 10:2773. [PMID: 31866965 PMCID: PMC6905131 DOI: 10.3389/fmicb.2019.02773] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 11/13/2019] [Indexed: 12/15/2022] Open
Abstract
Current suboptimal treatment options of invasive fungal infections and emerging resistance of the corresponding pathogens urge the need for alternative therapy strategies and require the identification of novel antifungal targets. Aspergillus fumigatus is the most common airborne opportunistic mold pathogen causing invasive and often fatal disease. Establishing a novel in vivo conditional gene expression system, we demonstrate that downregulation of the class 1 lysine deacetylase (KDAC) RpdA leads to avirulence of A. fumigatus in a murine model for pulmonary aspergillosis. The xylP promoter used has previously been shown to allow xylose-induced gene expression in different molds. Here, we demonstrate for the first time that this promoter also allows in vivo tuning of A. fumigatus gene activity by supplying xylose in the drinking water of mice. In the absence of xylose, an A. fumigatus strain expressing rpdA under control of the xylP promoter, rpdAxylP, was avirulent and lung histology showed significantly less fungal growth. With xylose, however, rpdAxylP displayed full virulence demonstrating that xylose was taken up by the mouse, transported to the site of fungal infection and caused rpdA induction in vivo. These results demonstrate that (i) RpdA is a promising target for novel antifungal therapies and (ii) the xylP expression system is a powerful new tool for in vivo gene silencing in A. fumigatus.
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Affiliation(s)
- Ingo Bauer
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Matthias Misslinger
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Yana Shadkchan
- Department of Clinical Microbiology and Immunology, Aspergillus and Antifungal Research Laboratory, Sackler School of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Anna-Maria Dietl
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Verena Petzer
- Department of Internal Medicine II (Infectious Diseases, Immunology, Rheumatology and Pneumology), Medical University of Innsbruck, Innsbruck, Austria
| | - Thomas Orasch
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Beate Abt
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Stefan Graessle
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Nir Osherov
- Department of Clinical Microbiology and Immunology, Aspergillus and Antifungal Research Laboratory, Sackler School of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Hubertus Haas
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
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Mózsik L, Büttel Z, Bovenberg RAL, Driessen AJM, Nygård Y. Synthetic control devices for gene regulation in Penicillium chrysogenum. Microb Cell Fact 2019; 18:203. [PMID: 31739777 PMCID: PMC6859608 DOI: 10.1186/s12934-019-1253-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/10/2019] [Indexed: 12/01/2022] Open
Abstract
Background Orthogonal, synthetic control devices were developed for Penicillium chrysogenum, a model filamentous fungus and industrially relevant cell factory. In the synthetic transcription factor, the QF DNA-binding domain of the transcription factor of the quinic acid gene cluster of Neurospora crassa is fused to the VP16 activation domain. This synthetic transcription factor controls the expression of genes under a synthetic promoter containing quinic acid upstream activating sequence (QUAS) elements, where it binds. A gene cluster may demand an expression tuned individually for each gene, which is a great advantage provided by this system. Results The control devices were characterized with respect to three of their main components: expression of the synthetic transcription factors, upstream activating sequences, and the affinity of the DNA binding domain of the transcription factor to the upstream activating domain. This resulted in synthetic expression devices, with an expression ranging from hardly detectable to a level similar to that of highest expressed native genes. The versatility of the control device was demonstrated by fluorescent reporters and its application was confirmed by synthetically controlling the production of penicillin. Conclusions The characterization of the control devices in microbioreactors, proved to give excellent indications for how the devices function in production strains and conditions. We anticipate that these well-characterized and robustly performing control devices can be widely applied for the production of secondary metabolites and other compounds in filamentous fungi.![]()
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Affiliation(s)
- László Mózsik
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Zsófia Büttel
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Roel A L Bovenberg
- DSM Biotechnology Center, Alexander Fleminglaan 1, 2613 AX, Delft, The Netherlands.,Synthetic Biology and Cell Engineering, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Arnold J M Driessen
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Yvonne Nygård
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands. .,DSM Biotechnology Center, Alexander Fleminglaan 1, 2613 AX, Delft, The Netherlands. .,Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96, Gothenburg, Sweden.
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36
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Cairns TC, Feurstein C, Zheng X, Zhang LH, Zheng P, Sun J, Meyer V. Functional exploration of co-expression networks identifies a nexus for modulating protein and citric acid titres in Aspergillus niger submerged culture. Fungal Biol Biotechnol 2019; 6:18. [PMID: 31728200 PMCID: PMC6842248 DOI: 10.1186/s40694-019-0081-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 10/21/2019] [Indexed: 01/10/2023] Open
Abstract
Background Filamentous fungal cell factories are used to produce numerous proteins, enzymes, and organic acids. Protein secretion and filamentous growth are tightly coupled at the hyphal tip. Additionally, both these processes require ATP and amino acid precursors derived from the citric acid cycle. Despite this interconnection of organic acid production and protein secretion/filamentous growth, few studies in fungi have identified genes which may concomitantly impact all three processes. Results We applied a novel screen of a global co-expression network in the cell factory Aspergillus niger to identify candidate genes which may concomitantly impact macromorphology, and protein/organic acid fermentation. This identified genes predicted to encode the Golgi localized ArfA GTPase activating protein (GAP, AgeB), and ArfA guanine nucleotide exchange factors (GEFs SecG and GeaB) to be co-expressed with citric acid cycle genes. Consequently, we used CRISPR-based genome editing to place the titratable Tet-on expression system upstream of ageB, secG, and geaB in A. niger. Functional analysis revealed that ageB and geaB are essential whereas secG was dispensable for early filamentous growth. Next, gene expression was titrated during submerged cultivations under conditions for either protein or organic acid production. ArfA regulators played varied and culture-dependent roles on pellet formation. Notably, ageB or geaB expression levels had major impacts on protein secretion, whereas secG was dispensable. In contrast, reduced expression of each predicted ArfA regulator resulted in an absence of citric acid in growth media. Finally, titrated expression of either GEFs resulted in an increase in oxaloacetic acid concentrations in supernatants. Conclusion Our data suggest that the Golgi may play an underappreciated role in modulating organic acid titres during industrial applications, and that this is SecG, GeaB and AgeB dependent in A. niger. These data may lead to novel avenues for strain optimization in filamentous fungi for improved protein and organic acid titres.
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Affiliation(s)
- Timothy C Cairns
- 1Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People's Republic of China.,2Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People's Republic of China
| | - Claudia Feurstein
- 1Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People's Republic of China.,2Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People's Republic of China.,3Institute of Biotechnology, Chair of Applied and Molecular Microbiology, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Xiaomei Zheng
- 1Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People's Republic of China.,2Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People's Republic of China.,4University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Li Hui Zhang
- 1Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People's Republic of China.,2Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People's Republic of China.,5College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457 China
| | - Ping Zheng
- 1Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People's Republic of China.,2Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People's Republic of China.,4University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Jibin Sun
- 1Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People's Republic of China.,2Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People's Republic of China.,4University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Vera Meyer
- 1Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People's Republic of China.,2Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People's Republic of China.,3Institute of Biotechnology, Chair of Applied and Molecular Microbiology, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany.,4University of Chinese Academy of Sciences, Beijing, 100049 China
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37
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Strategies for gene disruption and expression in filamentous fungi. Appl Microbiol Biotechnol 2019; 103:6041-6059. [DOI: 10.1007/s00253-019-09953-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 05/24/2019] [Accepted: 05/28/2019] [Indexed: 02/02/2023]
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38
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Gene expression engineering in fungi. Curr Opin Biotechnol 2019; 59:141-149. [PMID: 31154079 DOI: 10.1016/j.copbio.2019.04.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 03/27/2019] [Accepted: 04/24/2019] [Indexed: 02/03/2023]
Abstract
Fungi are a highly diverse group of microbial species that possess a plethora of biotechnologically useful metabolic and physiological properties. Important enablers for fungal biology studies and their biotechnological use are well-performing gene expression tools. Different types of gene expression tools exist; however, typically they are at best only functional in one or a few closely related species. This has hampered research and development of industrially relevant production systems. Here, we review operational principles and concepts of fungal gene expression tools. We present an overview on tools that utilize endogenous fungal promoters and modified hybrid expression systems composed of engineered promoters and transcription factors. Finally, we review synthetic expression tools that are functional across a broad range of fungal species.
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39
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Cairns TC, Zheng X, Zheng P, Sun J, Meyer V. Moulding the mould: understanding and reprogramming filamentous fungal growth and morphogenesis for next generation cell factories. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:77. [PMID: 30988699 PMCID: PMC6446404 DOI: 10.1186/s13068-019-1400-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/09/2019] [Indexed: 05/21/2023]
Abstract
Filamentous fungi are harnessed as cell factories for the production of a diverse range of organic acids, proteins, and secondary metabolites. Growth and morphology have critical implications for product titres in both submerged and solid-state fermentations. Recent advances in systems-level understanding of the filamentous lifestyle and development of sophisticated synthetic biological tools for controlled manipulation of fungal genomes now allow rational strain development programs based on data-driven decision making. In this review, we focus on Aspergillus spp. and other industrially utilised fungi to summarise recent insights into the multifaceted and dynamic relationship between filamentous growth and product titres from genetic, metabolic, modelling, subcellular, macromorphological and process engineering perspectives. Current progress and knowledge gaps with regard to mechanistic understanding of product secretion and export from the fungal cell are discussed. We highlight possible strategies for unlocking lead genes for rational strain optimizations based on omics data, and discuss how targeted genetic manipulation of these candidates can be used to optimise fungal morphology for improved performance. Additionally, fungal signalling cascades are introduced as critical processes that can be genetically targeted to control growth and morphology during biotechnological applications. Finally, we review progress in the field of synthetic biology towards chassis cells and minimal genomes, which will eventually enable highly programmable filamentous growth and diversified production capabilities. Ultimately, these advances will not only expand the fungal biotechnology portfolio but will also significantly contribute to a sustainable bio-economy.
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Affiliation(s)
- Timothy C. Cairns
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
| | - Xiaomei Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
| | - Ping Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
| | - Jibin Sun
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
| | - Vera Meyer
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- Department of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany
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Martin-Vicente A, Souza ACO, Al Abdallah Q, Ge W, Fortwendel JR. SH3-class Ras guanine nucleotide exchange factors are essential for Aspergillus fumigatus invasive growth. Cell Microbiol 2019; 21:e13013. [PMID: 30698898 PMCID: PMC6522298 DOI: 10.1111/cmi.13013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 12/11/2018] [Accepted: 01/22/2019] [Indexed: 01/23/2023]
Abstract
Proper hyphal morphogenesis is essential for the establishment and progression of invasive disease caused by filamentous fungi. In the human pathogen Aspergillus fumigatus, signalling cascades driven by Ras and Ras‐like proteins orchestrate a wide variety of cellular processes required for hyphal growth. For activation, these proteins require interactions with Ras‐subfamily‐specific guanine nucleotide exchange factors (RasGEFs). Although Ras‐protein networks are essential for virulence in all pathogenic fungi, the importance of RasGEF proteins is largely unexplored. A. fumigatus encodes four putative RasGEFs that represent three separate classes of RasGEF proteins (SH3‐, Ras guanyl nucleotide‐releasing protein [RasGRP]–, and LTE‐class), each with fungus‐specific attributes. Here, we show that the SH3‐class and RasGRP‐class RasGEFs are required for properly timed polarity establishment during early growth and branch emergence as well as for cell wall stability. Further, we show that SH3‐class RasGEF activity is essential for polarity establishment and maintenance, a phenotype that is, at least, partially independent of the major A. fumigatus Ras proteins, RasA and RasB. Finally, loss of both SH3‐class RasGEFs resulted in avirulence in multiple models of invasive aspergillosis. Together, our findings suggest that RasGEF activity is essential for the integration of multiple signalling networks to drive invasive growth in A. fumigatus.
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Affiliation(s)
- Adela Martin-Vicente
- Department of Clinical Pharmacy and Translational Science, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Ana Camila Oliveira Souza
- Department of Clinical Pharmacy and Translational Science, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Qusai Al Abdallah
- Department of Clinical Pharmacy and Translational Science, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Wenbo Ge
- Department of Clinical Pharmacy and Translational Science, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Jarrod R Fortwendel
- Department of Clinical Pharmacy and Translational Science, University of Tennessee Health Science Center, Memphis, Tennessee, USA
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Cairns TC, Feurstein C, Zheng X, Zheng P, Sun J, Meyer V. A quantitative image analysis pipeline for the characterization of filamentous fungal morphologies as a tool to uncover targets for morphology engineering: a case study using aplD in Aspergillus niger. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:149. [PMID: 31223339 PMCID: PMC6570962 DOI: 10.1186/s13068-019-1473-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 05/20/2019] [Indexed: 05/05/2023]
Abstract
BACKGROUND Fungal fermentation is used to produce a diverse repertoire of enzymes, chemicals, and drugs for various industries. During submerged cultivation, filamentous fungi form a range of macromorphologies, including dispersed mycelia, clumped aggregates, or pellets, which have critical implications for rheological aspects during fermentation, gas/nutrient transfer, and, thus, product titres. An important component of strain engineering efforts is the ability to quantitatively assess fungal growth phenotypes, which will drive novel leads for morphologically optimized production strains. RESULTS In this study, we developed an automated image analysis pipeline to quantify the morphology of pelleted and dispersed growth (MPD) which rapidly and reproducibly measures dispersed and pelleted macromorphologies from any submerged fungal culture. It (i) enables capture and analysis of several hundred images per user/day, (ii) is designed to quantitatively assess heterogeneous cultures consisting of dispersed and pelleted forms, (iii) gives a quantitative measurement of culture heterogeneity, (iv) automatically generates key Euclidian parameters for individual fungal structures including particle diameter, aspect ratio, area, and solidity, which are also assembled into a previously described dimensionless morphology number MN, (v) has an in-built quality control check which enables end-users to easily confirm the accuracy of the automated calls, and (vi) is easily adaptable to user-specified magnifications and macromorphological definitions. To concomitantly provide proof of principle for the utility of this image analysis pipeline, and provide new leads for morphologically optimized fungal strains, we generated a morphological mutant in the cell factory Aspergillus niger based on CRISPR-Cas technology. First, we interrogated a previously published co-expression networks for A. niger to identify a putative gamma-adaptin encoding gene (aplD) that was predicted to play a role in endosome cargo trafficking. Gene editing was used to generate a conditional aplD expression mutant under control of the titratable Tet-on system. Reduced aplD expression caused a hyperbranched growth phenotype and diverse defects in pellet formation with a putative increase in protein secretion. This possible protein hypersecretion phenotype could be correlated with increased dispersed mycelia, and both decreased pellet diameter and MN. CONCLUSION The MPD image analysis pipeline is a simple, rapid, and flexible approach to quantify diverse fungal morphologies. As an exemplar, we have demonstrated that the putative endosomal transport gene aplD plays a crucial role in A. niger filamentous growth and pellet formation during submerged culture. This suggests that endocytic components are underexplored targets for engineering fungal cell factories.
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Affiliation(s)
- Timothy C. Cairns
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
| | - Claudia Feurstein
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- Department of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany
| | - Xiaomei Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Ping Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Jibin Sun
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Vera Meyer
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 People’s Republic of China
- Department of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany
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Zhang F, Bunterngsook B, Li JX, Zhao XQ, Champreda V, Liu CG, Bai FW. Regulation and production of lignocellulolytic enzymes from Trichoderma reesei for biofuels production. ADVANCES IN BIOENERGY 2019. [DOI: 10.1016/bs.aibe.2019.03.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Schwarz C, Vandeputte P, Rougeron A, Giraud S, Dugé de Bernonville T, Duvaux L, Gastebois A, Alastruey-Izquierdo A, Martín-Gomez MT, Mazuelos EM, Sole A, Cano J, Pemán J, Quindos G, Botterel F, Bougnoux ME, Chen S, Delhaès L, Favennec L, Ranque S, Sedlacek L, Steinmann J, Vazquez J, Williams C, Meyer W, Le Gal S, Nevez G, Fleury M, Papon N, Symoens F, Bouchara JP. Developing collaborative works for faster progress on fungal respiratory infections in cystic fibrosis. Med Mycol 2018. [PMID: 29538733 DOI: 10.1093/mmy/myx106] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cystic fibrosis (CF) is the major genetic inherited disease in Caucasian populations. The respiratory tract of CF patients displays a sticky viscous mucus, which allows for the entrapment of airborne bacteria and fungal spores and provides a suitable environment for growth of microorganisms, including numerous yeast and filamentous fungal species. As a consequence, respiratory infections are the major cause of morbidity and mortality in this clinical context. Although bacteria remain the most common agents of these infections, fungal respiratory infections have emerged as an important cause of disease. Therefore, the International Society for Human and Animal Mycology (ISHAM) has launched a working group on Fungal respiratory infections in Cystic Fibrosis (Fri-CF) in October 2006, which was subsequently approved by the European Confederation of Medical Mycology (ECMM). Meetings of this working group, comprising both clinicians and mycologists involved in the follow-up of CF patients, as well as basic scientists interested in the fungal species involved, provided the opportunity to initiate collaborative works aimed to improve our knowledge on these infections to assist clinicians in patient management. The current review highlights the outcomes of some of these collaborative works in clinical surveillance, pathogenesis and treatment, giving special emphasis to standardization of culture procedures, improvement of species identification methods including the development of nonculture-based diagnostic methods, microbiome studies and identification of new biological markers, and the description of genotyping studies aiming to differentiate transient carriage and chronic colonization of the airways. The review also reports on the breakthrough in sequencing the genomes of the main Scedosporium species as basis for a better understanding of the pathogenic mechanisms of these fungi, and discusses treatment options of infections caused by multidrug resistant microorganisms, such as Scedosporium and Lomentospora species and members of the Rasamsonia argillacea species complex.
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Affiliation(s)
- Carsten Schwarz
- Department of Pediatric Pneumology and Immunology, Cystic Fibrosis Center Berlin/Charité -Universitätsmedizin Berlin, Berlin, Germany
| | - Patrick Vandeputte
- Host-Pathogen Interaction Study Group (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France.,Laboratoire de Parasitologie-Mycologie, CHU, Angers, France
| | - Amandine Rougeron
- Université de Bordeaux, Microbiologie Fondamentale et Pathogénicité UMR 5234, Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France; Laboratoire de Parasitologie-Mycologie, CHU, Bordeaux, France
| | - Sandrine Giraud
- Host-Pathogen Interaction Study Group (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France
| | - Thomas Dugé de Bernonville
- Biomolécules et Biotechnologies Végétales (EA 2106), Département de Biologie et Physiologie Végétales, UFR Sciences et Techniques, Université François Rabelais, Tours
| | - Ludovic Duvaux
- Host-Pathogen Interaction Study Group (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France.,Institut de Recherche en Horticulture et Semences (IRHS), UMR INRA 1345, Beaucouzé, France
| | - Amandine Gastebois
- Host-Pathogen Interaction Study Group (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France
| | - Ana Alastruey-Izquierdo
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Maria Teresa Martín-Gomez
- Respiratory Bacteriology Unit & Clinical Mycology Unit, Department of Microbiology, Vall D'Hebron University Hospital, Universitat Autònoma de Barcelona, Barcelona, Spain
| | | | - Amparo Sole
- Unidad de Trasplante Pulmonar y Fibrosis Quística, Hospital Universitari la Fe, Valencia, Spain
| | - Josep Cano
- Mycology Unit, Medical School/Oenology School, Universitat Rovira i Virgili, Reus, Spain
| | - Javier Pemán
- Unidad de Micología, Servicio de Microbiología, Universitari la Fe, Valencia, Spain
| | - Guillermo Quindos
- Laboratorio de Micología Médica, Departamento de Inmunología, Microbiología y Parasitología, Facultad de Medicina y Enfermería, Universidad del País Vasco, Bilbao, Spain
| | - Françoise Botterel
- Laboratoire de Parasitologie-Mycologie, CHU Henri Mondor, Créteil, France
| | | | - Sharon Chen
- Centre for Infectious Diseases and Microbiology Laboratory Services, ICPMR - Pathology West, Westmead Hospital, Westmead, New South Wales, Australia
| | - Laurence Delhaès
- Center for Cardiothoracic Research of Bordeaux, Inserm U1045, Bordeaux, France
| | - Loïc Favennec
- Laboratoire de Parasitologie-Mycologie, EA 3800, CHU Charles Nicolle and Université de Rouen, Rouen, France
| | - Stéphane Ranque
- Laboratoire de Parasitologie-Mycologie, AP-HM Timone, Marseille, France
| | - Ludwig Sedlacek
- Institute of Medical Microbiology and Hospital Epidemiology, Medical School Hannover, Hannover, Germany
| | - Joerg Steinmann
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Jose Vazquez
- Division of Infectious Diseases, Department of Medicine, Georgia Regents University, Augusta, GA, USA
| | - Craig Williams
- University of the West of Scotland, Institute of Healthcare Associated Infection, University Hospital Crosshouse, Kilmarnock, United Kingdom
| | - Wieland Meyer
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Sydney Medical School, Westmead Clinical School, Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Westmead Hospital, Westmead Institute for Medical Research, Westmead, NSW, Australia
| | - Solène Le Gal
- Host-Pathogen Interaction Study Group (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Brest, France.,Laboratoire de Parasitologie-Mycologie, CHU, Brest, France
| | - Gilles Nevez
- Host-Pathogen Interaction Study Group (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Brest, France.,Laboratoire de Parasitologie-Mycologie, CHU, Brest, France
| | - Maxime Fleury
- Host-Pathogen Interaction Study Group (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France
| | - Nicolas Papon
- Host-Pathogen Interaction Study Group (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France
| | - Françoise Symoens
- Host-Pathogen Interaction Study Group (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France
| | - Jean-Philippe Bouchara
- Host-Pathogen Interaction Study Group (EA 3142), UNIV Angers, UNIV Brest, Université Bretagne-Loire, Angers, France.,Laboratoire de Parasitologie-Mycologie, CHU, Angers, France
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Fitz E, Wanka F, Seiboth B. The Promoter Toolbox for Recombinant Gene Expression in Trichoderma reesei. Front Bioeng Biotechnol 2018; 6:135. [PMID: 30364340 PMCID: PMC6193071 DOI: 10.3389/fbioe.2018.00135] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/12/2018] [Indexed: 01/05/2023] Open
Abstract
The ascomycete Trichoderma reesei is one of the main fungal producers of cellulases and xylanases based on its high production capacity. Its enzymes are applied in food, feed, and textile industry or in lignocellulose hydrolysis in biofuel and biorefinery industry. Over the last years, the demand to expand the molecular toolbox for T. reesei to facilitate genetic engineering and improve the production of heterologous proteins grew. An important instrument to modify the expression of key genes are promoters to initiate and control their transcription. To date, the most commonly used promoter for T. reesei is the strong inducible promoter of the main cellobiohydrolase cel7a. Beside this one, there is a number of alternative inducible promoters derived from other cellulase- and xylanase encoding genes and a few constitutive promoters. With the advances in genomics and transcriptomics the identification of new constitutive and tunable promoters with different expression strength was simplified. In this review, we will discuss new developments in the field of promoters and compare their advantages and disadvantages. Synthetic expression systems constitute a new option to control gene expression and build up complex gene circuits. Therefore, we will address common structural features of promoters and describe options for promoter engineering and synthetic design of promoters. The availability of well-characterized gene expression control tools is essential for the analysis of gene function, detection of bottlenecks in gene networks and yield increase for biotechnology applications.
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Affiliation(s)
- Elisabeth Fitz
- Research Division Biochemical Technology, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria.,Austrian Centre of Industrial Biotechnology (ACIB) GmbH, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria
| | - Franziska Wanka
- Austrian Centre of Industrial Biotechnology (ACIB) GmbH, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria
| | - Bernhard Seiboth
- Research Division Biochemical Technology, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria.,Austrian Centre of Industrial Biotechnology (ACIB) GmbH, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria
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45
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Inducible promoters and functional genomic approaches for the genetic engineering of filamentous fungi. Appl Microbiol Biotechnol 2018; 102:6357-6372. [PMID: 29860590 PMCID: PMC6061484 DOI: 10.1007/s00253-018-9115-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/17/2018] [Accepted: 05/18/2018] [Indexed: 12/15/2022]
Abstract
In industry, filamentous fungi have a prominent position as producers of economically relevant primary or secondary metabolites. Particularly, the advent of genetic engineering of filamentous fungi has led to a growing number of molecular tools to adopt filamentous fungi for biotechnical applications. Here, we summarize recent developments in fungal biology, where fungal host systems were genetically manipulated for optimal industrial applications. Firstly, available inducible promoter systems depending on carbon sources are mentioned together with various adaptations of the Tet-Off and Tet-On systems for use in different industrial fungal host systems. Subsequently, we summarize representative examples, where diverse expression systems were used for the production of heterologous products, including proteins from mammalian systems. In addition, the progressing usage of genomics and functional genomics data for strain improvement strategies are addressed, for the identification of biosynthesis genes and their related metabolic pathways. Functional genomic data are further used to decipher genomic differences between wild-type and high-production strains, in order to optimize endogenous metabolic pathways that lead to the synthesis of pharmaceutically relevant end products. Lastly, we discuss how molecular data sets can be used to modify products for optimized applications.
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Cairns TC, Nai C, Meyer V. How a fungus shapes biotechnology: 100 years of Aspergillus niger research. Fungal Biol Biotechnol 2018; 5:13. [PMID: 29850025 PMCID: PMC5966904 DOI: 10.1186/s40694-018-0054-5] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 04/12/2018] [Indexed: 12/20/2022] Open
Abstract
In 1917, a food chemist named James Currie made a promising discovery: any strain of the filamentous mould Aspergillus niger would produce high concentrations of citric acid when grown in sugar medium. This tricarboxylic acid, which we now know is an intermediate of the Krebs cycle, had previously been extracted from citrus fruits for applications in food and beverage production. Two years after Currie’s discovery, industrial-level production using A. niger began, the biochemical fermentation industry started to flourish, and industrial biotechnology was born. A century later, citric acid production using this mould is a multi-billion dollar industry, with A. niger additionally producing a diverse range of proteins, enzymes and secondary metabolites. In this review, we assess main developments in the field of A. niger biology over the last 100 years and highlight scientific breakthroughs and discoveries which were influential for both basic and applied fungal research in and outside the A. niger community. We give special focus to two developments of the last decade: systems biology and genome editing. We also summarize the current international A. niger research community, and end by speculating on the future of fundamental research on this fascinating fungus and its exploitation in industrial biotechnology.
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Affiliation(s)
- Timothy C Cairns
- Department of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Corrado Nai
- Department of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Vera Meyer
- Department of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
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47
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Fiedler MRM, Cairns TC, Koch O, Kubisch C, Meyer V. Conditional Expression of the Small GTPase ArfA Impacts Secretion, Morphology, Growth, and Actin Ring Position in Aspergillus niger. Front Microbiol 2018; 9:878. [PMID: 29867795 PMCID: PMC5952172 DOI: 10.3389/fmicb.2018.00878] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 04/16/2018] [Indexed: 12/26/2022] Open
Abstract
In filamentous fungi, growth and protein secretion occurs predominantly at the tip of long, thread like cells termed hyphae. This requires coordinated regulation of multiple processes, including vesicle trafficking, exocytosis, and endocytosis, which are facilitated by a complex cytoskeletal apparatus. In this study, functional analyses of the small GTPase ArfA from Aspergillus niger demonstrate that this protein functionally complements the Saccharomyces cerevisiae ARF1/2, and that this protein is essential for A. niger. Loss-of-function and gain-of-function analyses demonstrate that titration of arfA expression impacts hyphal growth rate, hyphal tip morphology, and protein secretion. Moreover, localization of the endocytic machinery, visualized via fluorescent tagging of the actin ring, was found to be abnormal in ArfA under- and overexpressed conditions. Finally, we provide evidence that the major secreted protein GlaA localizes at septal junctions, indicating that secretion in A. niger may occur at these loci, and that this process is likely impacted by arfA expression levels. Taken together, our results demonstrate that ArfA fulfills multiple functions in the secretory pathway of A. niger.
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Affiliation(s)
- Markus R M Fiedler
- Department of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Timothy C Cairns
- Department of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Oliver Koch
- Department of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Christin Kubisch
- Department of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Vera Meyer
- Department of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
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48
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Fuller KK, Dunlap JC, Loros JJ. Light-regulated promoters for tunable, temporal, and affordable control of fungal gene expression. Appl Microbiol Biotechnol 2018; 102:3849-3863. [PMID: 29569180 DOI: 10.1007/s00253-018-8887-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 02/19/2018] [Accepted: 02/20/2018] [Indexed: 01/08/2023]
Abstract
Regulatable promoters are important genetic tools, particularly for assigning function to essential and redundant genes. They can also be used to control the expression of enzymes that influence metabolic flux or protein secretion, thereby optimizing product yield in bioindustry. This review will focus on regulatable systems for use in filamentous fungi, an important group of organisms whose members include key research models, devastating pathogens of plants and animals, and exploitable cell factories. Though we will begin by cataloging those promoters that are controlled by nutritional or chemical means, our primary focus will rest on those who can be controlled by a literal flip-of-the-switch: promoters of light-regulated genes. The vvd promoter of Neurospora will first serve as a paradigm for how light-driven systems can provide tight, robust, tunable, and temporal control of either autologous or heterologous fungal proteins. We will then discuss a theoretical approach to, and practical considerations for, the development of such promoters in other species. To this end, we have compiled genes from six previously published light-regulated transcriptomic studies to guide the search for suitable photoregulatable promoters in your fungus of interest.
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Affiliation(s)
- Kevin K Fuller
- Department of Molecular and Systems Biology, Geisel School of Medicine, Hanover, NH, USA.
| | - Jay C Dunlap
- Department of Molecular and Systems Biology, Geisel School of Medicine, Hanover, NH, USA
| | - Jennifer J Loros
- Department of Molecular and Systems Biology, Geisel School of Medicine, Hanover, NH, USA. .,Department of Biochemistry and Cell Biology, Geisel School of Medicine, Hanover, NH, USA.
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Zheng X, Zheng P, Sun J, Kun Z, Ma Y. Heterologous and endogenous U6 snRNA promoters enable CRISPR/Cas9 mediated genome editing in Aspergillus niger. Fungal Biol Biotechnol 2018; 5:2. [PMID: 29456867 PMCID: PMC5806293 DOI: 10.1186/s40694-018-0047-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 12/23/2017] [Indexed: 01/11/2023] Open
Abstract
Background U6 promoters have been used for single guide RNA (sgRNA) transcription in the clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas9) genome editing system. However, no available U6 promoters have been identified in Aspergillus niger, which is an important industrial platform for organic acid and protein production. Two CRISPR/Cas9 systems established in A. niger have recourse to the RNA polymerase II promoter or in vitro transcription for sgRNA synthesis, but these approaches generally increase cloning efforts and genetic manipulation. The validation of functional RNA polymerase II promoters is therefore an urgent need for A. niger. Results Here, we developed a novel CRISPR/Cas9 system in A. niger for sgRNA expression, based on one endogenous U6 promoter and two heterologous U6 promoters. The three tested U6 promoters enabled sgRNA transcription and the disruption of the polyketide synthase albA gene in A. niger. Furthermore, this system enabled highly efficient gene insertion at the targeted genome loci in A. niger using donor DNAs with homologous arms as short as 40-bp. Conclusions This study demonstrated that both heterologous and endogenous U6 promoters were functional for sgRNA expression in A. niger. Based on this result, a novel and simple CRISPR/Cas9 toolbox was established in A. niger, that will benefit future gene functional analysis and genome editing.
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Affiliation(s)
- Xiaomei Zheng
- 1Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Xiqidao 32, Tianjin Airport Economic Area, Tianjin, 300308 China.,2Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Ping Zheng
- 1Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Xiqidao 32, Tianjin Airport Economic Area, Tianjin, 300308 China.,2Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Jibin Sun
- 1Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Xiqidao 32, Tianjin Airport Economic Area, Tianjin, 300308 China.,2Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Zhang Kun
- 1Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Xiqidao 32, Tianjin Airport Economic Area, Tianjin, 300308 China.,2Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China.,3University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Yanhe Ma
- 1Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Xiqidao 32, Tianjin Airport Economic Area, Tianjin, 300308 China
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50
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Peng Y, Zhang H, Xu M, Tan MW. A Tet-Off gene expression system for validation of antifungal drug targets in a murine invasive pulmonary aspergillosis model. Sci Rep 2018; 8:443. [PMID: 29323188 PMCID: PMC5765126 DOI: 10.1038/s41598-017-18868-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 12/18/2017] [Indexed: 12/20/2022] Open
Abstract
Aspergillus fumigatus is one of the major causes of invasive pulmonary aspergillosis in immunocompromised patients. Novel antifungal therapy is in urgent need due to emerging resistance and adverse toxicity of current antifungal drugs. Gene products that are essential for Aspergillus viability during infection are attractive drug targets. To characterize these genes in vivo we developed a Tet-Off gene expression system in A. fumigatus, whereby the administration of doxycycline resulted in down regulation of the gene whose expression is under the control of the Tet-Off promoter. We tested the system on two potential drug targets, inosine 5′-monophosphate dehydrogenase (IMPDH) and L-ornithine N5-oxygenase (sidA) in a murine invasive pulmonary aspergillosis model. We show that depletion of IMPDH attenuated but did not completely abolish virulence in vivo whereas turning off the expression of sidA, which is required for iron acquisition, resulted in avirulence. We also investigated whether sidA expression could be controlled in a time-dependent manner in mice. Our results demonstrated that timing of doxycycline administration dramatically affects survival rate, suggesting that this genetic system can be used for testing whether an antifungal drug target is critical for fungal growth post-infection.
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Affiliation(s)
- Yutian Peng
- Infectious Diseases Department, Genentech Inc., South San Francisco, California, 94080, USA.
| | - Hua Zhang
- Translational Immunology Department, Genentech Inc., South San Francisco, California, 94080, USA
| | - Min Xu
- Translational Immunology Department, Genentech Inc., South San Francisco, California, 94080, USA
| | - Man-Wah Tan
- Infectious Diseases Department, Genentech Inc., South San Francisco, California, 94080, USA.
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