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Li H, Zhu J, Li Z, Xu P, Ma L, Zou Y, Qu S, Wu X. Contrasting effects of NADPH oxidases on the fungal hyphae growth and immune responses in Pleurotus ostreatus. Front Microbiol 2024; 15:1387643. [PMID: 38962136 PMCID: PMC11220167 DOI: 10.3389/fmicb.2024.1387643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Accepted: 06/03/2024] [Indexed: 07/05/2024] Open
Abstract
Pleurotus ostreatus is one of the most consumed mushroom species, as it serves as a high-quality food, favors a rich secondary metabolism, and has remarkable adaptability to the environment and predators. In this study, we investigated the function of two key reactive oxygen species producing enzyme NADPH oxidase (PoNoxA and PoNoxB) in P. ostreatus hyphae growth, metabolite production, signaling pathway activation, and immune responses to different stresses. Characterization of the Nox mutants showed that PoNoxB played an important role in the hyphal formation of the multicellular structure, while PoNoxA regulated apical dominance. The ability of P. ostreatus to tolerate a series of abiotic stress conditions (e.g., osmotic, oxidative, membrane, and cell-wall stresses) and mechanical damage repair was enhanced with PoNoxA over-expression. PoNoxB had a greater responsibility in regulating the polysaccharide composition of the cell wall and methyl jasmonate and gibberellin GA1 biosynthesis, and improved mushroom resistance against Tyrophagus putrescentiae. Moreover, mutants were involved in the jasmonate and GA signaling pathway, and toxic protein defense metabolite production. Our findings shed light on how the oyster mushroom senses stress signals and responds to adverse environments by the complex regulators of Noxs.
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Affiliation(s)
- Huiping Li
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, Jiangsu, China
- Institute of Vegetable Crops, Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China
| | - Jiachun Zhu
- Institute of Vegetable Crops, Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Zihao Li
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ping Xu
- Institute of Vegetable Crops, Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China
| | - Lin Ma
- Institute of Vegetable Crops, Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China
| | - Yajie Zou
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shaoxuan Qu
- Institute of Vegetable Crops, Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Xiaoqin Wu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, Jiangsu, China
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Müller H, Deffur C, Schmideder S, Barthel L, Friedrich T, Mirlach L, Hammel JU, Meyer V, Briesen H. Synchrotron radiation-based microcomputed tomography for three-dimensional growth analysis of Aspergillus niger pellets. Biotechnol Bioeng 2023; 120:3244-3260. [PMID: 37475650 DOI: 10.1002/bit.28506] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/05/2023] [Accepted: 07/11/2023] [Indexed: 07/22/2023]
Abstract
Filamentous fungi produce a wide range of relevant biotechnological compounds. The close relationship between fungal morphology and productivity has led to a variety of analytical methods to quantify their macromorphology. Nevertheless, only a µ-computed tomography (µ-CT) based method allows a detailed analysis of the 3D micromorphology of fungal pellets. However, the low sample throughput of a laboratory µ-CT limits the tracking of the micromorphological evolution of a statistically representative number of submerged cultivated fungal pellets over time. To meet this challenge, we applied synchrotron radiation-based X-ray microtomography at the Deutsches Elektronen-Synchrotron [German Electron Synchrotron Research Center], resulting in 19,940 3D analyzed individual fungal pellets that were obtained from 26 sampling points during a 48 h Aspergillus niger submerged batch cultivation. For each of the pellets, we were able to determine micromorphological properties such as number and density of spores, tips, branching points, and hyphae. The computed data allowed us to monitor the growth of submerged cultivated fungal pellets in highly resolved 3D for the first time. The generated morphological database from synchrotron measurements can be used to understand, describe, and model the growth of filamentous fungal cultivations.
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Affiliation(s)
- Henri Müller
- School of Life Sciences Weihenstephan, Chair of Process Systems Engineering, Technical University of Munich, Freising, Germany
| | - Charlotte Deffur
- School of Life Sciences Weihenstephan, Chair of Process Systems Engineering, Technical University of Munich, Freising, Germany
| | - Stefan Schmideder
- School of Life Sciences Weihenstephan, Chair of Process Systems Engineering, Technical University of Munich, Freising, Germany
| | - Lars Barthel
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Tiaan Friedrich
- School of Life Sciences Weihenstephan, Chair of Process Systems Engineering, Technical University of Munich, Freising, Germany
| | - Lukas Mirlach
- School of Life Sciences Weihenstephan, Chair of Process Systems Engineering, Technical University of Munich, Freising, Germany
| | - Jörg U Hammel
- Helmholtz-Zentrum hereon, Institute of Materials Physics, Geesthacht, Germany
| | - Vera Meyer
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Heiko Briesen
- School of Life Sciences Weihenstephan, Chair of Process Systems Engineering, Technical University of Munich, Freising, Germany
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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: 7] [Impact Index Per Article: 7.0] [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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Qin L, Yang L, Zhao J, Zeng W, Su M, Wang S, Yuan J. GTPase Rac Regulates Conidiation, AFB1 Production and Stress Response in Pathogenic Fungus Aspergillus flavus. Toxins (Basel) 2022; 14:toxins14090581. [PMID: 36136519 PMCID: PMC9503438 DOI: 10.3390/toxins14090581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/14/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022] Open
Abstract
As a member of the Rho family, Rac plays important roles in many species, including proliferation, differentiation, apoptosis, DNA damage responses, metabolism, angiogenesis, and immunosuppression. In this study, by constructing Rac-deleted mutants in Aspergillus flavus, it was found that the deletion of Rac gene led to the decline of growth and development, conidia production, AFB1 toxin synthesis, and seed infection ability of A. flavus. The deletion of Rac gene also caused the disappearance of A. flavus sclerotium, indicating that Rac is required for sclerotium formation in A. flavus. The sensitivity of Rac-deficient strains responding to cell wall stress and osmotic pressure stress increased when compared to A.flavus WT. The Western blot result showed that mitogen-activated serine/threonine-protein kinase Slt2 and mitogen-activated protein kinase Hog1 proteins were no longer phosphorylated in Rac-deficient strains of A. flavus, showing that Rac may be used as a molecular switch to control the Slt2-MAPK cascade pathway and regulate the osmotic Hog-MAPK cascade pathway in A. flavus in response to external stress. Altogether, these results indicated that Rac was involved in regulating the growth and development, conidia formation and AFB1 synthesis, and response to cell wall stress and osmotic pressure stress in A. flavus.
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Müller H, Barthel L, Schmideder S, Schütze T, Meyer V, Briesen H. From spores to fungal pellets: a new high throughput image analysis highlights the structural development of Aspergillus niger. Biotechnol Bioeng 2022; 119:2182-2195. [PMID: 35477834 DOI: 10.1002/bit.28124] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 03/21/2022] [Accepted: 04/22/2022] [Indexed: 11/10/2022]
Abstract
Many filamentous fungi are exploited as cell factories in biotechnology. Cultivated under industrially relevant submerged conditions, filamentous fungi can adopt different macromorphologies ranging from dispersed mycelia over loose clumps to pellets. Central to the development of a pellet morphology is the agglomeration of spores after inoculation followed by spore germination and outgrowth into a pellet population which is usually very heterogeneous. As the dynamics underlying population heterogeneity are not yet fully understood, we present here a new high-throughput image analysis pipeline based on stereomicroscopy to comprehensively assess the developmental program starting from germination up to pellet formation. To demonstrate the potential of this pipeline, we used data from 44 sampling times harvested during a 48 h submerged batch cultivation of the fungal cell factory Aspergillus niger. The analysis of up to 1700 spore agglomerates and 1500 pellets per sampling time allowed the precise tracking of the morphological development of the overall culture. The data gained were used to calculate size distributions and area fractions of spores, spore agglomerates, spore agglomerates within pellets, pellets, and dispersed mycelia. This approach eventually enables the quantification of culture heterogeneities and pellet breakage. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Henri Müller
- Technical University of Munich, School of Life Sciences Weihenstephan, Chair of Process Systems Engineering, Freising, Germany
| | - Lars Barthel
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Stefan Schmideder
- Technical University of Munich, School of Life Sciences Weihenstephan, Chair of Process Systems Engineering, Freising, Germany
| | - Tabea Schütze
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Vera Meyer
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Heiko Briesen
- Technical University of Munich, School of Life Sciences Weihenstephan, Chair of Process Systems Engineering, Freising, Germany
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6
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Henning LM, Simon U, Abdullayev A, Schmidt B, Pohl C, Nunez Guitar T, Vakifahmetoglu C, Meyer V, Bekheet MF, Gurlo A. Effect of Fomes fomentarius Cultivation Conditions on Its Adsorption Performance for Anionic and Cationic Dyes. ACS OMEGA 2022; 7:4158-4169. [PMID: 35155910 PMCID: PMC8829953 DOI: 10.1021/acsomega.1c05748] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/24/2021] [Indexed: 06/14/2023]
Abstract
Lab-cultivated mycelia of Fomes fomentarius (FF), grown on a solid lignocellulose medium (FF-SM) and a liquid glucose medium (FF-LM), and naturally grown fruiting bodies (FF-FB) were studied as biosorbents for the removal of organic dyes methylene blue and Congo red (CR). Both the chemical and microstructural differences were revealed using X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, zeta potential analysis, and scanning electron microscopy, illuminating the superiority of FF-LM and FF-SM over FF-FB in dye adsorption. The adsorption process of CR on FF-LM and FF-SM is best described by the Redlich-Peterson model with β constants close to 1, that is, approaching the monolayer Langmuir model, which reach maximum adsorption capacities of 48.8 and 13.4 mg g-1, respectively, in neutral solutions. Adsorption kinetics follow the pseudo-second-order model where chemisorption is the rate-controlling step. While the desorption efficiencies were low, adsorption performances were preserved and even enhanced under simulated dye effluent conditions. The results suggest that F. fomentarius can be considered an attractive biosorbent in industrial wastewater treatment and that its cultivation conditions can be specifically tailored to tune its cell wall composition and adsorption performance.
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Affiliation(s)
- Laura M. Henning
- Chair
of Advanced Ceramic Materials, Institute of Material Science and Technology,
Faculty III Process Sciences, Technische
Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Ulla Simon
- Chair
of Advanced Ceramic Materials, Institute of Material Science and Technology,
Faculty III Process Sciences, Technische
Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Amanmyrat Abdullayev
- Chair
of Advanced Ceramic Materials, Institute of Material Science and Technology,
Faculty III Process Sciences, Technische
Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Bertram Schmidt
- Chair
of Applied and Molecular Microbiology, Institute of Biotechnology,
Faculty III Process Sciences, Technische
Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Carsten Pohl
- Chair
of Applied and Molecular Microbiology, Institute of Biotechnology,
Faculty III Process Sciences, Technische
Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Tamara Nunez Guitar
- Chair
of Applied and Molecular Microbiology, Institute of Biotechnology,
Faculty III Process Sciences, Technische
Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Cekdar Vakifahmetoglu
- Department
of Materials Science and Engineering, Izmir
Institute of Technology, Urla, 35430 Izmir, Turkey
| | - Vera Meyer
- Chair
of Applied and Molecular Microbiology, Institute of Biotechnology,
Faculty III Process Sciences, Technische
Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Maged F. Bekheet
- Chair
of Advanced Ceramic Materials, Institute of Material Science and Technology,
Faculty III Process Sciences, Technische
Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Aleksander Gurlo
- Chair
of Advanced Ceramic Materials, Institute of Material Science and Technology,
Faculty III Process Sciences, Technische
Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
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8
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Turning Inside Out: Filamentous Fungal Secretion and Its Applications in Biotechnology, Agriculture, and the Clinic. J Fungi (Basel) 2021; 7:jof7070535. [PMID: 34356914 PMCID: PMC8307877 DOI: 10.3390/jof7070535] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/14/2021] [Accepted: 06/25/2021] [Indexed: 12/15/2022] Open
Abstract
Filamentous fungi are found in virtually every marine and terrestrial habitat. Vital to this success is their ability to secrete a diverse range of molecules, including hydrolytic enzymes, organic acids, and small molecular weight natural products. Industrial biotechnologists have successfully harnessed and re-engineered the secretory capacity of dozens of filamentous fungal species to make a diverse portfolio of useful molecules. The study of fungal secretion outside fermenters, e.g., during host infection or in mixed microbial communities, has also led to the development of novel and emerging technological breakthroughs, ranging from ultra-sensitive biosensors of fungal disease to the efficient bioremediation of polluted environments. In this review, we consider filamentous fungal secretion across multiple disciplinary boundaries (e.g., white, green, and red biotechnology) and product classes (protein, organic acid, and secondary metabolite). We summarize the mechanistic understanding for how various molecules are secreted and present numerous applications for extracellular products. Additionally, we discuss how the control of secretory pathways and the polar growth of filamentous hyphae can be utilized in diverse settings, including industrial biotechnology, agriculture, and the clinic.
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Vázquez-Fuentes S, Pelagio-Flores R, López-Bucio J, Torres-Gavilán A, Campos-García J, de la Cruz HR, López-Bucio JS. N-vanillyl-octanamide represses growth of fungal phytopathogens in vitro and confers postharvest protection in tomato and avocado fruits against fungal-induced decay. PROTOPLASMA 2021; 258:729-741. [PMID: 33410981 DOI: 10.1007/s00709-020-01586-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 11/18/2020] [Indexed: 06/12/2023]
Abstract
Plant diseases caused by pathogenic fungi result in considerable losses in agriculture. The use of fungicides is an important alternative to combat these pathogens, but may affect both the environment and human health. Plants produce many bioactive compounds to defend themselves from biotic challenges and an increasing number of secondary metabolites have been identified, which may be used to control fungal infections. Here, the bioactivity of a synthetic capsaicinoid, N-vanillyl-octanamide, also termed ABX-I, in the growth of five phytopathogenic fungi was assessed in vitro. The compound inhibited growth of Colletotrichum gloeosporioides, Botrytis cinerea, Colletotrichum acutatum, Fusarium sp., and Rhizoctonia solani AG2, while the magnitude of this effect differed from capsaicin. To investigate if ABX-I could effectively protect crops against phytopathogens, fungal challenges were performed in tomato leaves and fruits, as well as avocado fruits co-infiltrated with Botrytis cinerea or Colletotrichum gloeosporioides, respectively. In both tomato leaves and fruits and avocado fruits, ABX-I decreased the fungal damage not only in vegetative but also in edible tissues, and diminished decay symptoms compared with untreated fruits, which were highly sensitive to the pathogens. Furthermore, ABX-I spray application to tomato or avocado plants did not compromise growth and development, whereas it repressed spore germination and growth of C. gloeosporioides, which suggests its potential as an affordable and promising resource to control fungal diseases in the agronomic sector.
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Affiliation(s)
- Saúl Vázquez-Fuentes
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P., 58030, Morelia, Michoacán, Mexico
| | - Ramón Pelagio-Flores
- Facultad de Químico Farmacobiología, Universidad Michoacana de San Nicolás de Hidalgo, Tzintzuntzan 173, Matamoros, C. P., 58240, Morelia, Michoacán, Mexico
| | - José López-Bucio
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P., 58030, Morelia, Michoacán, Mexico
| | | | - Jesús Campos-García
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P., 58030, Morelia, Michoacán, Mexico
| | - Homero Reyes de la Cruz
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P., 58030, Morelia, Michoacán, Mexico
| | - Jesús Salvador López-Bucio
- CONACYT-Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P., 58030, Morelia, Michoacán, Mexico.
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11
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Bodie E, Virag A, Pratt RJ, Leiva N, Ward M, Dodge T. Reduced viscosity mutants of Trichoderma reesei with improved industrial fermentation characteristics. J Ind Microbiol Biotechnol 2021; 48:kuab014. [PMID: 33599729 PMCID: PMC9113505 DOI: 10.1093/jimb/kuab014] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 11/14/2022]
Abstract
Morphological mutants of Trichoderma reesei were isolated following chemical or insertional mutagenesis. The mutant strains were shown to have reduced viscosity under industrially relevant fermentation conditions and to have maintained high specific productivity of secreted protein. This allowed higher biomass concentration to be maintained during the production phase and, consequently, increased volumetric productivity of secreted protein. The causative mutations were traced to four individual genes (designated sfb3, ssb7, seb1, and mpg1). We showed that two of the morphological mutations could be combined in a single strain to further reduce viscosity and enable a 100% increase in volumetric productivity.
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Affiliation(s)
| | | | - Robert J Pratt
- Nutrition and Biosciences, DuPont, Palo Alto, CA
94304, USA
| | - Nicholas Leiva
- Nutrition and Biosciences, DuPont, Palo Alto, CA
94304, USA
| | - Michael Ward
- Nutrition and Biosciences, DuPont, Palo Alto, CA
94304, USA
| | - Tim Dodge
- Nutrition and Biosciences, DuPont, Palo Alto, CA
94304, USA
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12
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Demirci E, Arentshorst M, Yilmaz B, Swinkels A, Reid ID, Visser J, Tsang A, Ram AFJ. Genetic Characterization of Mutations Related to Conidiophore Stalk Length Development in Aspergillus niger Laboratory Strain N402. Front Genet 2021; 12:666684. [PMID: 33959152 PMCID: PMC8093798 DOI: 10.3389/fgene.2021.666684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/29/2021] [Indexed: 11/29/2022] Open
Abstract
Aspergillus niger is an important filamentous fungus in industrial biotechnology for the production of citric acid and enzymes. In the late 1980s, the A. niger N400/NRRL3 strain was selected for both fundamental and applied studies in relation to several processes including gluconic acid and protein production. To facilitate handling of A. niger, the N400 wild-type strain was UV mutagenized in two consecutive rounds to generate N401 and N402. N402 was used as a reference laboratory strain and exhibits the phenotypes with reduced conidiophore stalk length and reduced radial growth. The conidiophore stalk length and radial growth of A. niger strain N400 were determined and compared to N401 and N402. The length of N400 conidiophore stalks (2.52 ± 0.40 mm) was reduced in N401 and N402 to 0.66 ± 0.14 mm and 0.34 ± 0.06 mm, respectively. Whereas N400 reached a colony diameter of 6.7 ± 0.2 cm after 7 days, N401 and N402 displayed reduced radial growth phenotype (4.3 ± 0.1 and 4.1 ± 0.1, respectively). To identify the mutations (dubbed cspA and cspB) responsible for the phenotypes of N401 and N402, the genomes were sequenced and compared to the N400 genome sequence. A parasexual cross was performed between N400 and N402 derivatives to isolate segregants which allowed cosegregation analysis of single nucleotide polymorphisms and insertions and deletions among the segregants. The shorter conidiophore stalk and reduced radial growth in N401 (cspA) was found to be caused by a 9-kb deletion on chromosome III and was further narrowed down to a truncation of NRRL3_03857 which encodes a kinesin-like protein homologous to the A. nidulans UncA protein. The mutation responsible for the further shortening of conidiophore stalks in N402 (cspB) was found to be caused by a missense mutation on chromosome V in a hitherto unstudied C2H2 transcription factor encoded by the gene NRRL3_06646. The importance of these two genes in relation to conidiophore stalk length and radial growth was confirmed by single and double gene deletion studies. The mutations in the laboratory strain N402 should be taken into consideration when studying phenotypes in the N402 background.
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Affiliation(s)
- Ebru Demirci
- Institute of Biology Leiden, Microbial Sciences, Leiden University, Leiden, Netherlands
| | - Mark Arentshorst
- Institute of Biology Leiden, Microbial Sciences, Leiden University, Leiden, Netherlands
| | - Baran Yilmaz
- Institute of Biology Leiden, Microbial Sciences, Leiden University, Leiden, Netherlands
| | - Aram Swinkels
- Institute of Biology Leiden, Microbial Sciences, Leiden University, Leiden, Netherlands
| | - Ian D Reid
- Centre for Structural and Functional Genomics, Concordia University, Montreal, QC, Canada
| | - Jaap Visser
- Institute of Biology Leiden, Microbial Sciences, Leiden University, Leiden, Netherlands.,Fungal Genetics and Technology Consultancy, Wageningen, Netherlands
| | - Adrian Tsang
- Centre for Structural and Functional Genomics, Concordia University, Montreal, QC, Canada
| | - Arthur F J Ram
- Institute of Biology Leiden, Microbial Sciences, Leiden University, Leiden, Netherlands
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13
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Cortesão M, de Haas A, Unterbusch R, Fujimori A, Schütze T, Meyer V, Moeller R. Aspergillus niger Spores Are Highly Resistant to Space Radiation. Front Microbiol 2020; 11:560. [PMID: 32318041 PMCID: PMC7146846 DOI: 10.3389/fmicb.2020.00560] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 03/16/2020] [Indexed: 12/20/2022] Open
Abstract
The filamentous fungus Aspergillus niger is one of the main contaminants of the International Space Station (ISS). It forms highly pigmented, airborne spores that have thick cell walls and low metabolic activity, enabling them to withstand harsh conditions and colonize spacecraft surfaces. Whether A. niger spores are resistant to space radiation, and to what extent, is not yet known. In this study, spore suspensions of a wild-type and three mutant strains (with defects in pigmentation, DNA repair, and polar growth control) were exposed to X-rays, cosmic radiation (helium- and iron-ions) and UV-C (254 nm). To assess the level of resistance and survival limits of fungal spores in a long-term interplanetary mission scenario, we tested radiation doses up to 1000 Gy and 4000 J/m2. For comparison, a 360-day round-trip to Mars yields a dose of 0.66 ± 0.12 Gy. Overall, wild-type spores of A. niger were able to withstand high doses of X-ray (LD90 = 360 Gy) and cosmic radiation (helium-ion LD90 = 500 Gy; and iron-ion LD90 = 100 Gy). Drying the spores before irradiation made them more susceptible toward X-ray radiation. Notably, A. niger spores are highly resistant to UV-C radiation (LD90 = 1038 J/m2), which is significantly higher than that of other radiation-resistant microorganisms (e.g., Deinococcus radiodurans). In all strains, UV-C treated spores (1000 J/m2) were shown to have decreased biofilm formation (81% reduction in wild-type spores). This study suggests that A. niger spores might not be easily inactivated by exposure to space radiation alone and that current planetary protection guidelines should be revisited, considering the high resistance of fungal spores.
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Affiliation(s)
- Marta Cortesão
- Space Microbiology Research Group, Radiation Biology Department, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Aram de Haas
- Space Microbiology Research Group, Radiation Biology Department, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Rebecca Unterbusch
- Space Microbiology Research Group, Radiation Biology Department, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Akira Fujimori
- Department of Basic Medical Sciences for Radiation Damages, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Tabea Schütze
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Vera Meyer
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Ralf Moeller
- Space Microbiology Research Group, Radiation Biology Department, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
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14
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Fitz E, Gamauf C, Seiboth B, Wanka F. Deletion of the small GTPase rac1 in Trichoderma reesei provokes hyperbranching and impacts growth and cellulase production. Fungal Biol Biotechnol 2019; 6:16. [PMID: 31641527 PMCID: PMC6798449 DOI: 10.1186/s40694-019-0078-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 10/03/2019] [Indexed: 11/21/2022] Open
Abstract
Background Trichoderma reesei is widely known for its enormous protein secretion capacity and as an industrially relevant producer of cellulases and hemicellulases. Over the last decades, rational strain engineering was applied to further enhance homologous and heterologous enzyme yields. The introduction of hyperbranching is believed to increase protein secretion, since most exocytosis is located at the hyphal apical tip. There are several genetic modifications which can cause hyperbranching, for example the deletion of the small Rho GTPase rac. Rac plays a crucial role in actin dynamics and is involved in polarisation of the cell during germination and apical extension of the hyphae. Results We deleted rac1 in a T. reesei strain with an ectopically overexpressed endoglucanase, CEL12A, under Pcdna1 control. This deletion provoked a hyperbranching phenotype and strong apolar growth during germination and in mature hyphae. The strains displayed dichotomous branching and shorter total mycelium length with a larger hyphal diameter. Δrac1 strains exhibited a decreased radial growth on solid media. Biomass formation in liquid cultures was carbon source dependent; similar to the reference strain during growth on lactose, increased on d-glucose and slightly enhanced on cellulose. While extracellular cellulase activities remained at parental strain levels on d-glucose and cellulose, the specific activity on lactose cultures was increased up to three times at 72 h accompanied by an upregulation of transcription of the main cellulases. Although the morphology of the Δrac1 strains was considerably altered, the viscosity of the culture broth in fed-batch cultivations were not significantly different in comparison to the parental strain. Conclusions Deletion of the small Rho GTPase rac1 changes the morphology of the hyphae and provokes hyperbranching without affecting viscosity, independent of the carbon source. In contrast, biomass formation and cellulase production are altered in a carbon source dependent manner in the Δrac1 strains.
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Affiliation(s)
- Elisabeth Fitz
- 1Research Division Biochemical Technology, Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Vienna, Austria.,2Austrian Centre of Industrial Biotechnology (ACIB) GmbH c/o Research Division Biochemical Technology, Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Vienna, Austria
| | - Christian Gamauf
- 3Group Biotechnology, Clariant Produkte (Deutschland) GmbH, Planegg, Germany
| | - Bernhard Seiboth
- 1Research Division Biochemical Technology, Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Vienna, Austria.,2Austrian Centre of Industrial Biotechnology (ACIB) GmbH c/o Research Division Biochemical Technology, Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Vienna, Austria
| | - Franziska Wanka
- 2Austrian Centre of Industrial Biotechnology (ACIB) GmbH c/o Research Division Biochemical Technology, Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, Vienna, Austria
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15
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Kwon MJ, Schütze T, Spohner S, Haefner S, Meyer V. Practical guidance for the implementation of the CRISPR genome editing tool in filamentous fungi. Fungal Biol Biotechnol 2019; 6:15. [PMID: 31641526 PMCID: PMC6796461 DOI: 10.1186/s40694-019-0079-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 10/05/2019] [Indexed: 12/27/2022] Open
Abstract
Background Within the last years, numerous reports described successful application of the CRISPR nucleases Cas9 and Cpf1 for genome editing in filamentous fungi. However, still a lot of efforts are invested to develop and improve protocols for the fungus and genes of interest with respect to applicability, scalability and targeting efficiencies. These efforts are often hampered by the fact that-although many different protocols are available-none have systematically analysed and compared different CRISPR nucleases and different application procedures thereof for the efficiency of single- and multiplex-targeting approaches in the same fungus. Results We present here data for successful genome editing in the cell factory Thermothelomyces thermophilus, formerly known as Myceliophthora thermophila, using the three different nucleases SpCas9, FnCpf1, AsCpf1 guided to four different gene targets of our interest. These included a polyketide synthase (pks4.2), an alkaline protease (alp1), a SNARE protein (snc1) and a potential transcription factor (ptf1). For all four genes, guide RNAs were developed which enabled successful single-targeting and multiplex-targeting. CRISPR nucleases were either delivered to T. thermophilus on plasmids or preassembled with in vitro transcribed gRNA to form ribonucleoproteins (RNPs). We also evaluated the efficiency of single oligonucleotides for site-directed mutagenesis. Finally, we were able to scale down the transformation protocol to microtiter plate format which generated high numbers of positive transformants and will thus pave the way for future high-throughput investigations. Conclusion We provide here the first comprehensive analysis and evaluation of different CRISPR approaches for a filamentous fungus. All approaches followed enabled successful genome editing in T. thermophilus; however, with different success rates. In addition, we show that the success rate depends on the respective nuclease and on the targeted gene locus. We finally present a practical guidance for experimental considerations aiming to guide the reader for successful implementation of CRISPR technology for other fungi.
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Affiliation(s)
- Min Jin Kwon
- 1Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, 10263 Berlin, Germany
| | - Tabea Schütze
- 1Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, 10263 Berlin, Germany
| | | | - Stefan Haefner
- 2BASF SE, Carl-Bosch-Strasse 38, 67056 Ludwigshafen, Germany
| | - Vera Meyer
- 1Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, 10263 Berlin, Germany
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16
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Hühn J, Musielak M, Schmitz HP, Heinisch JJ. Fungal homologues of human Rac1 as emerging players in signal transduction and morphogenesis. Int Microbiol 2019; 23:43-53. [PMID: 31020478 DOI: 10.1007/s10123-019-00077-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 03/28/2019] [Accepted: 04/02/2019] [Indexed: 02/06/2023]
Abstract
A wealth of data is accumulating on the physiological functions of human Rac1, a member of the Rho GTPase family of molecular switches and substrate of botulinum toxin, which was first identified as a regulator of cell motility through its effect on the actin cytoskeleton. Later on, it was found to be involved in different diseases like cancers, cardiac function, neuronal disorders, and apoptotic cell death. Despite the presence of Rac1 homologues in most fungi investigated so far, including Rho5 in the genetically tractable model yeast Saccharomyces cerevisiae, knowledge on their physiological functions is still scarce, let alone the details of the molecular mechanisms of their actions and interactions. Nevertheless, all functions proposed for human Rac1 seem to be conserved in one or the other fungus. This includes the regulation of MAPK cascades, polarized growth, and actin dynamics. Moreover, both the production and response to reactive oxygen species, as well as the reaction to nutrient availability, can be affected. We here summarize the studies performed on fungal Rac1 homologues, with a special focus on S. cerevisiae Rho5, which may be of use in drug development in medicine and agriculture.
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Affiliation(s)
- Julia Hühn
- Department of Biology and Chemistry, Genetics group, University of Osnabrück, Barbarastrasse 11, 49076, Osnabrück, Germany
| | - Marius Musielak
- Department of Biology and Chemistry, Genetics group, University of Osnabrück, Barbarastrasse 11, 49076, Osnabrück, Germany
| | - Hans-Peter Schmitz
- Department of Biology and Chemistry, Genetics group, University of Osnabrück, Barbarastrasse 11, 49076, Osnabrück, Germany
| | - Jürgen J Heinisch
- Department of Biology and Chemistry, Genetics group, University of Osnabrück, Barbarastrasse 11, 49076, Osnabrück, Germany.
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17
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Sun X, Su X. Harnessing the knowledge of protein secretion for enhanced protein production in filamentous fungi. World J Microbiol Biotechnol 2019; 35:54. [PMID: 30900052 DOI: 10.1007/s11274-019-2630-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 03/08/2019] [Indexed: 12/19/2022]
Abstract
Filamentous fungi are important microorganisms used in industrial production of proteins and enzymes. Among these organisms, Trichoderma reesei, Aspergilli, and more recently Myceliophthora thermophile are the most widely used and promising ones which have powerful protein secretion capability. In recent years, there have been tremendous achievements in understanding the molecular mechanisms of the secretory pathways in filamentous fungi. The acquired pieces of knowledge can be harnessed to enhance protein production in filamentous fungi with assistance of state-of-the-art genetic engineering techniques.
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Affiliation(s)
- Xianhua Sun
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 South Zhongguancun Street, Beijing, 100081, China
| | - Xiaoyun Su
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 South Zhongguancun Street, Beijing, 100081, China.
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18
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Tong Z, Zheng X, Tong Y, Shi YC, Sun J. Systems metabolic engineering for citric acid production by Aspergillus niger in the post-genomic era. Microb Cell Fact 2019; 18:28. [PMID: 30717739 PMCID: PMC6362574 DOI: 10.1186/s12934-019-1064-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 01/16/2019] [Indexed: 11/11/2022] Open
Abstract
Citric acid is the world’s largest consumed organic acid and is widely used in beverage, food and pharmaceutical industries. Aspergillus niger is the main industrial workhorse for citric acid production. Since the release of the genome sequence, extensive multi-omic data are being rapidly obtained, which greatly boost our understanding of the citric acid accumulation mechanism in A. niger to a molecular and system level. Most recently, the rapid development of CRISPR/Cas9 system facilitates highly efficient genome-scale genetic perturbation in A. niger. In this review, we summarize the impact of systems biology on the citric acid molecular regulatory mechanisms, the advances in metabolic engineering strategies for enhancing citric acid production and discuss the development and application of CRISPR/Cas9 systems for genome editing in A. niger. We believe that future systems metabolic engineering efforts will redesign and engineer A. niger as a highly optimized cell factory for industrial citric acid production.
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Affiliation(s)
- Zhenyu Tong
- Department of Grain Science and Industry, Kansas State University, Manhattan, KS, 66506, USA
| | - 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
| | - Yi Tong
- COFCO Biochemical (Anhui) Co. Ltd, Bengbu, 233000, People's Republic of China
| | - Yong-Cheng Shi
- Department of Grain Science and Industry, Kansas State University, Manhattan, KS, 66506, USA
| | - 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.
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19
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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: 63] [Impact Index Per Article: 12.6] [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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20
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Wang KF, Guo C, Ju F, Samak NA, Zhuang GQ, Liu CZ. Farnesol-induced hyperbranched morphology with short hyphae and bulbous tips of Coriolus versicolor. Sci Rep 2018; 8:15213. [PMID: 30315269 PMCID: PMC6185903 DOI: 10.1038/s41598-018-33435-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 06/13/2018] [Indexed: 12/02/2022] Open
Abstract
As the first fungal quorum sensing molecule, farnesol-induced morphological transition is usually studied in dimorphic fungi, but in basidiomycetes the morphological changes regulated by farnesol are rarely investigated. In this study, we found that farnesol made the basidiomycete Coriolus versicolor develop into a hyperbranched morphology with short hyphae and bulbous tips. Farnesol treatment resulted in a significant increase of intracellular oxidative stress level, which influenced the expression of several morphogenesis-related genes, and thereby led to the morphological changes. High oxidative stress level significantly stimulated the expression of laccase genes for improving intracellular laccase biosynthesis. The resulted hyperbranched morphology further accelerated the secretion of intracellular laccase into culture medium. As a result, extracellular laccase production reached a maximum of 2189.2 ± 54.7 U/L in farnesol-induced cultures, which was 6.8-fold greater than that of control cultures. SDS-PAGE and native-PAGE showed that farnesol increased laccase production by promoting the biosynthesis of three laccase isoforms. Together these results provide new opportunities in not only understanding the farnesol-regulated mycelial morphology in basidiomycetes, but also developing novel strategies for enhancing the production of secreted enzymes of biotechnological interest.
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Affiliation(s)
- Ke-Feng Wang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, P.R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Chen Guo
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, P.R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Fang Ju
- Department of Oncology, Qingdao Central Hospital, Qingdao, 266042, P.R. China.
| | - Nadia A Samak
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, P.R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Guo-Qiang Zhuang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, P.R. China
| | - Chun-Zhao Liu
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, P.R. China. .,University of Chinese Academy of Sciences, Beijing, 100049, P.R. China. .,Institute of Biochemical Engineering, Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province, School of Materials Science and Engineering, Qingdao University, Qingdao, 266071, P.R. China.
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21
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Fiedler MRM, Barthel L, Kubisch C, Nai C, Meyer V. Construction of an improved Aspergillus niger platform for enhanced glucoamylase secretion. Microb Cell Fact 2018; 17:95. [PMID: 29908567 PMCID: PMC6004097 DOI: 10.1186/s12934-018-0941-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/08/2018] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND The lifestyle of filamentous fungi depends on the secretion of hydrolytic enzymes into the surrounding medium, which degrade polymeric substances into monomers that are then taken up to sustain metabolism. This feature has been exploited in biotechnology to establish platform strains with high secretory capacity including Aspergillus niger. The accepted paradigm is that proteins become mainly secreted at the tips of fungal hyphae. However, it is still a matter of debate if the amount of growing hyphal tips in filamentous fungi correlates with an increase in secretion, with previous studies showing either a positive or no correlation. RESULTS Here, we followed a systematic approach to study protein secretion in A. niger. First, we put the glaA gene encoding for glucoamylase (GlaA), the most abundant secreted protein of A. niger, under control of the tunable Tet-on system. Regulation of glaA gene expression by omitting or adding the inducer doxycycline to cultivation media allowed us to study the effect of glaA under- or overexpression in the same isolate. By inducing glaA expression in a fluorescently tagged v-SNARE reporter strain expressing GFP-SncA, we could demonstrate that the amount of post-Golgi carriers indeed depends on and correlates with glaA gene expression. By deleting the racA gene, encoding the Rho-GTPase RacA in this isolate, we generated a strain which is identical to the parental strain with respect to biomass formation but produces about 20% more hyphal tips. This hyperbranching phenotype caused a more compact macromorphology in shake flask cultivations. When ensuring continuous high-level expression of glaA by repeated addition of doxycycline, this hyperbranching strain secreted up to four times more GlaA into the culture medium compared to its parental strain. CONCLUSION The data obtained in this study strongly indicate that A. niger responds to forced transcription of secretory enzymes with increased formation of post-Golgi carriers to efficiently accommodate the incoming cargo load. This physiological adaptation can be rationally exploited to generate hypersecretion platforms based on a hyperbranching phenotype. We propose that a racA deletion background serves as an excellent chassis for such hypersecretion strains.
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Affiliation(s)
- Markus R. M. Fiedler
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Lars Barthel
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Christin Kubisch
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Corrado Nai
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Vera Meyer
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
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22
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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: 131] [Impact Index Per Article: 21.8] [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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23
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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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24
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He R, Li C, Ma L, Zhang D, Chen S. Effect of highly branched hyphal morphology on the enhanced production of cellulase in Trichoderma reesei DES-15. 3 Biotech 2016; 6:214. [PMID: 28330286 PMCID: PMC5052222 DOI: 10.1007/s13205-016-0516-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 09/08/2016] [Indexed: 01/10/2023] Open
Abstract
The morphology of Trichoderma reesei is a vitally important factor for cellulase productivity. This study investigated the effect of hyphal morphology on cellulase production in the hyper-cellulolytic mutant, T. reesei DES-15. With a distinct morphology, T. reesei DES-15 was obtained through Diethyl sulfite (DES) mutagenesis. The hyphal morphology of DES-15 batch-cultured in a 5-L fermentor was significantly shorter and more branched than the parental strain RUT C30. The cellulase production of DES-15 during batch fermentation was 66 % greater than that of RUT C30 when cultured the same conditions. DES-15 secreted nearly 50 % more protein than RUT C30. The gene expression level of a set of genes (cla4, spa2, ras2, ras1, rhoA, cdc42, and racA) known to be involved in hyphae growth and hyphal branching was measured by quantitative real-time PCR. The transcriptional analysis of these genes demonstrated that a decrease in gene expressions might contribute to the increased hyphal branching seen in DES-15. These results indicated that the highly branching hyphae in DES-15 resulted in increased cellulase production, suggesting that DES-15 may be a good candidate for use in the large-scale production of cellulase.
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Affiliation(s)
- Ronglin He
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China
- Tianjin Key Lab of Industrial Microbiology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China
| | - Chen Li
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
| | - Lijuan Ma
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China
| | - Dongyuan Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
| | - Shulin Chen
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
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25
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Meyer V, Fiedler M, Nitsche B, King R. The Cell Factory Aspergillus Enters the Big Data Era: Opportunities and Challenges for Optimising Product Formation. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2015; 149:91-132. [PMID: 25616499 DOI: 10.1007/10_2014_297] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Living with limits. Getting more from less. Producing commodities and high-value products from renewable resources including waste. What is the driving force and quintessence of bioeconomy outlines the lifestyle and product portfolio of Aspergillus, a saprophytic genus, to which some of the top-performing microbial cell factories belong: Aspergillus niger, Aspergillus oryzae and Aspergillus terreus. What makes them so interesting for exploitation in biotechnology and how can they help us to address key challenges of the twenty-first century? How can these strains become trimmed for better growth on second-generation feedstocks and how can we enlarge their product portfolio by genetic and metabolic engineering to get more from less? On the other hand, what makes it so challenging to deduce biological meaning from the wealth of Aspergillus -omics data? And which hurdles hinder us to model and engineer industrial strains for higher productivity and better rheological performance under industrial cultivation conditions? In this review, we will address these issues by highlighting most recent findings from the Aspergillus research with a focus on fungal growth, physiology, morphology and product formation. Indeed, the last years brought us many surprising insights into model and industrial strains. They clearly told us that similar is not the same: there are different ways to make a hypha, there are more protein secretion routes than anticipated and there are different molecular and physical mechanisms which control polar growth and the development of hyphal networks. We will discuss new conceptual frameworks derived from these insights and the future scientific advances necessary to create value from Aspergillus Big Data.
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Affiliation(s)
- Vera Meyer
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355, Berlin, Germany,
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Kwon MJ, Arentshorst M, Fiedler M, de Groen FLM, Punt PJ, Meyer V, Ram AFJ. Molecular genetic analysis of vesicular transport in Aspergillus niger reveals partial conservation of the molecular mechanism of exocytosis in fungi. Microbiology (Reading) 2014; 160:316-329. [DOI: 10.1099/mic.0.074252-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The filamentous fungus Aspergillus niger is an industrially exploited protein expression platform, well known for its capacity to secrete high levels of proteins. To study the process of protein secretion in A. niger, we established a GFP-v-SNARE reporter strain in which the trafficking and dynamics of secretory vesicles can be followed in vivo. The biological role of putative A. niger orthologues of seven secretion-specific genes, known to function in key aspects of the protein secretion machinery in Saccharomyces cerevisiae, was analysed by constructing respective gene deletion mutants in the GFP-v-SNARE reporter strain. Comparison of the deletion phenotype of conserved proteins functioning in the secretory pathway revealed common features but also interesting differences between S. cerevisiae and A. niger. Deletion of the S. cerevisiae Sec2p orthologue in A. niger (SecB), encoding a guanine exchange factor for the GTPase Sec4p (SrgA in A. niger), did not have an obvious phenotype, while SEC2 deletion in S. cerevisiae is lethal. Similarly, deletion of the A. niger orthologue of the S. cerevisiae exocyst subunit Sec3p (SecC) did not result in a lethal phenotype as in S. cerevisiae, although severe growth reduction of A. niger was observed. Deletion of secA, secH and ssoA (encoding SecA, SecH and SsoA the A. niger orthologues of S. cerevisiae Sec1p, Sec8p and Sso1/2p, respectively) showed that these genes are essential for A. niger, similar to the situation in S. cerevisiae. These data demonstrate that the orchestration of exocyst-mediated vesicle transport is only partially conserved in S. cerevisiae and A. niger.
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Affiliation(s)
- Min Jin Kwon
- Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, 2600 GA Delft, The Netherlands
- Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Mark Arentshorst
- Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Markus Fiedler
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Florence L. M. de Groen
- Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Peter J. Punt
- Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Vera Meyer
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
- Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, 2600 GA Delft, The Netherlands
- Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Arthur F. J. Ram
- Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, 2600 GA Delft, The Netherlands
- Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
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