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Shangguan J, Qiao J, Liu H, Zhu L, Han X, Shi L, Zhu J, Liu R, Ren A, Zhao M. The CBS/H 2S signalling pathway regulated by the carbon repressor CreA promotes cellulose utilization in Ganoderma lucidum. Commun Biol 2024; 7:466. [PMID: 38632386 PMCID: PMC11024145 DOI: 10.1038/s42003-024-06180-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: 10/17/2023] [Accepted: 04/10/2024] [Indexed: 04/19/2024] Open
Abstract
Cellulose is an important abundant renewable resource on Earth, and the microbial cellulose utilization mechanism has attracted extensive attention. Recently, some signalling molecules have been found to regulate cellulose utilization and the discovery of underlying signals has recently attracted extensive attention. In this paper, we found that the hydrogen sulfide (H2S) concentration under cellulose culture condition increased to approximately 2.3-fold compared with that under glucose culture condition in Ganoderma lucidum. Further evidence shown that cellulase activities of G. lucidum were improved by 18.2-27.6% through increasing H2S concentration. Then, we observed that the carbon repressor CreA inhibited H2S biosynthesis in G. lucidum by binding to the promoter of cbs, a key gene for H2S biosynthesis, at "CTGGGG". In our study, we reported for the first time that H2S increased the cellulose utilization in G. lucidum, and analyzed the mechanism of H2S biosynthesis induced by cellulose. This study not only enriches the understanding of the microbial cellulose utilization mechanism but also provides a reference for the analysis of the physiological function of H2S signals.
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Affiliation(s)
- Jiaolei Shangguan
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, PR China
| | - Jinjin Qiao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, PR China
| | - He Liu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, PR China
| | - Lei Zhu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, PR China
| | - Xiaofei Han
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, PR China
| | - Liang Shi
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, PR China
| | - Jing Zhu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, PR China
| | - Rui Liu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, PR China
| | - Ang Ren
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, PR China
| | - Mingwen Zhao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, PR China.
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Randhawa A, A Ogunyewo O, Jawed K, Yazdani SS. Calcium signaling positively regulates cellulase translation and secretion in a Clr-2-overexpressing, catabolically derepressed strain of Penicillium funiculosum. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:21. [PMID: 38336687 PMCID: PMC10858516 DOI: 10.1186/s13068-023-02448-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 12/13/2023] [Indexed: 02/12/2024]
Abstract
BACKGROUND Low-cost cellulase production is vital to sustainable second-generation biorefineries. The catabolically derepressed strain of Penicillium funiculosum NCIM1228 (PfMig188 or ∆Mig1) secretes a superior set of cellulolytic enzymes, that are most suitable for 2G biorefineries. At a 3% (w/w) load, the ∆Mig1 secretome can release > 80% of fermentable sugars from lignocellulose at a 15% (w/v) biomass load, irrespective of the type of biomass and pretreatment. The robustness of the secretome can be further increased by improving the cellulase production capacity of the fungal strain. RESULTS We began by identifying the transcription factor responsible for cellulase production in NCIM1228. An advanced RNA-seq screen identified three genes, clr-2, ctf1a and ctf1b; the genes were cloned under their native promoters and transformed into NCIM1228. Of the three, clr-2 overexpression led to twofold higher cellulase production than the parent strain and was thus identified as the transcriptional activator of cellulase in NCIM1228. Next, we overexpressed clr-2 in ∆Mig1 and expected an exponential increase in cellulolytic attributes accredited to the reinforced activation mechanisms, conjoint with diminished negative regulation. Although clr-2 overexpression increased the transcript levels of cellulase genes in ∆Mig1, there was no increase in cellulase yield. Even a further increase in the transcript levels of clr-2 via a stronger promoter was ineffective. However, when the CaCO3 concentration was increased to 5 g/l in the growth medium, we achieved a 1.5-fold higher activity of 6.4 FPU/ml in the ∆Mig1 strain with clr-2 overexpression. Enthused by the calcium effect, a transcriptomic screen for genes encoding Ca2+-activated kinase identified ssp1, whose overexpression could further increase cellulase yield to ~ 7.5 FPU/ml. Investigation of the mechanism revealed that calcium signaling exclusively enhances the translation and secretion of cellulase in Penicillium funiculosum. CONCLUSIONS Our study identifies for the first time that cellulose activates two discrete signaling events to govern cellulase transcription and posttranscriptional processes (translation, processing and secretion) in P. funiculosum NCIM1228. Whereas Clr-2, the transcriptional activator of cellulase, governs transcription, calcium signaling specifically activates cellulase translation and secretion.
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Affiliation(s)
- Anmoldeep Randhawa
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India.
- DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India.
- AMITY University, Mohali, Punjab, 140306, India.
| | - Olusola A Ogunyewo
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Kamran Jawed
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Syed Shams Yazdani
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India.
- DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India.
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Xie X, Wang Y, Jin S, He L, Jia Z, Huang B. MrCreC, a carbon catabolite repression gene, is required for the growth, conidiation, stress tolerance and virulence of Metarhizium robertsii. J Invertebr Pathol 2023; 201:108009. [PMID: 37863281 DOI: 10.1016/j.jip.2023.108009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 10/07/2023] [Accepted: 10/17/2023] [Indexed: 10/22/2023]
Abstract
As a key component of carbon source metabolism in fungi, CreC WD40 repeat protein is regulated by carbon catabolite repression (CCR). However, the understanding of the functions of CreC in entomopathogenic fungi is currently limited. Here, CreC in Metarhizium robertsii (MrCreC) was identified, and its roles in fungal development, conidiation, environmental stress response, and insecticidal virulence were explored. MrCreC is localized to cytoplasm, and MrCreC deletion affects fungal growth on various nutrients. Compared to the wild type, the sporulation of ΔMrCreC strain was significantly decreased by 60.3%. Further qPCR analysis found that deletion of MrCreC resulted in repression of sporulation-related genes such as AbaA, FlbA, Flbc, MedA, FlbD, FluG, and wetA. In addition, MrCreC loss did not alter heat stress tolerance but resulted in enhanced tolerance to UV-B. Interestingly, bioassays showed that the virulence following exposures to topical applications or injection of conidial suspensions of both infection and injection was impaired compared with that of the wild type. Further analysis showed that the adhesion and cuticle penetration genes in ΔMrCreC was down-regulated during infection, and the appressorial formation rate was significantly reduced. A deletion of MrCreC significantly also reduced immune escape and nutrient utilization genes in insect hemocoel. In conclusion, MrCreC is involved in the growth, development and virulence of M. robertsii. These findings advance our understanding of the function of CCR pathway-related genes.
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Affiliation(s)
- Xiangyun Xie
- College of Life Sciences, Liaocheng University, Liaocheng 252059, China
| | - Yulong Wang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei 230036, China
| | - Shaoxia Jin
- Taiyuan City Road Green Maintenance Center, Taiyuan 030000, China
| | - Lili He
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei 230036, China
| | - Zefeng Jia
- College of Life Sciences, Liaocheng University, Liaocheng 252059, China.
| | - Bo Huang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei 230036, China.
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Kerkaert JD, Huberman LB. Regulation of nutrient utilization in filamentous fungi. Appl Microbiol Biotechnol 2023; 107:5873-5898. [PMID: 37540250 PMCID: PMC10983054 DOI: 10.1007/s00253-023-12680-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/29/2023] [Accepted: 07/04/2023] [Indexed: 08/05/2023]
Abstract
Organisms must accurately sense and respond to nutrients to survive. In filamentous fungi, accurate nutrient sensing is important in the establishment of fungal colonies and in continued, rapid growth for the exploitation of environmental resources. To ensure efficient nutrient utilization, fungi have evolved a combination of activating and repressing genetic networks to tightly regulate metabolic pathways and distinguish between preferred nutrients, which require minimal energy and resources to utilize, and nonpreferred nutrients, which have more energy-intensive catabolic requirements. Genes necessary for the utilization of nonpreferred carbon sources are activated by transcription factors that respond to the presence of the specific nutrient and repressed by transcription factors that respond to the presence of preferred carbohydrates. Utilization of nonpreferred nitrogen sources generally requires two transcription factors. Pathway-specific transcription factors respond to the presence of a specific nonpreferred nitrogen source, while another transcription factor activates genes in the absence of preferred nitrogen sources. In this review, we discuss the roles of transcription factors and upstream regulatory genes that respond to preferred and nonpreferred carbon and nitrogen sources and their roles in regulating carbon and nitrogen catabolism. KEY POINTS: • Interplay of activating and repressing transcriptional networks regulates catabolism. • Nutrient-specific activating transcriptional pathways provide metabolic specificity. • Repressing regulatory systems differentiate nutrients in mixed nutrient environments.
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Affiliation(s)
- Joshua D Kerkaert
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | - Lori B Huberman
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA.
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5
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Pandit SS, Zheng J, Yin Y, Lorber S, Puel O, Dhingra S, Espeso EA, Calvo AM. Homeobox transcription factor HbxA influences expression of over one thousand genes in the model fungus Aspergillus nidulans. PLoS One 2023; 18:e0286271. [PMID: 37478074 PMCID: PMC10361519 DOI: 10.1371/journal.pone.0286271] [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: 02/24/2023] [Accepted: 05/11/2023] [Indexed: 07/23/2023] Open
Abstract
In fungi, conserved homeobox-domain proteins are transcriptional regulators governing development. In Aspergillus species, several homeobox-domain transcription factor genes have been identified, among them, hbxA/hbx1. For instance, in the opportunistic human pathogen Aspergillus fumigatus, hbxA is involved in conidial production and germination, as well as virulence and secondary metabolism, including production of fumigaclavines, fumiquinazolines, and chaetominine. In the agriculturally important fungus Aspergillus flavus, disruption of hbx1 results in fluffy aconidial colonies unable to produce sclerotia. hbx1 also regulates production of aflatoxins, cyclopiazonic acid and aflatrem. Furthermore, transcriptome studies revealed that hbx1 has a broad effect on the A. flavus genome, including numerous genes involved in secondary metabolism. These studies underline the importance of the HbxA/Hbx1 regulator, not only in developmental processes but also in the biosynthesis of a broad number of fungal natural products, including potential medical drugs and mycotoxins. To gain further insight into the regulatory scope of HbxA in Aspergilli, we studied its role in the model fungus Aspergillus nidulans. Our present study of the A. nidulans hbxA-dependent transcriptome revealed that more than one thousand genes are differentially expressed when this regulator was not transcribed at wild-type levels, among them numerous transcription factors, including those involved in development as well as in secondary metabolism regulation. Furthermore, our metabolomics analyses revealed that production of several secondary metabolites, some of them associated with A. nidulans hbxA-dependent gene clusters, was also altered in deletion and overexpression hbxA strains compared to the wild type, including synthesis of nidulanins A, B and D, versicolorin A, sterigmatocystin, austinol, dehydroaustinol, and three unknown novel compounds.
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Affiliation(s)
- Sandesh S. Pandit
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois, United States of America
| | - Jinfang Zheng
- Nebraska Food for Health Center, Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Yanbin Yin
- Nebraska Food for Health Center, Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Sophie Lorber
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Olivier Puel
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Sourabh Dhingra
- Department of Biological Sciences and Eukaryotic Pathogen Innovation Center, Clemson University, Clemson, South Carolina, United States of America
| | - Eduardo A. Espeso
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas (CSIC), Madrid, Spain
| | - Ana M. Calvo
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois, United States of America
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Pareek M, Hegedüs B, Hou Z, Csernetics Á, Wu H, Virágh M, Sahu N, Liu XB, Nagy L. Preassembled Cas9 Ribonucleoprotein-Mediated Gene Deletion Identifies the Carbon Catabolite Repressor and Its Target Genes in Coprinopsis cinerea. Appl Environ Microbiol 2022; 88:e0094022. [PMID: 36374019 PMCID: PMC9746306 DOI: 10.1128/aem.00940-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 10/11/2022] [Indexed: 11/16/2022] Open
Abstract
Cre1 is an important transcription factor that regulates carbon catabolite repression (CCR) and is widely conserved across fungi. The cre1 gene has been extensively studied in several Ascomycota species, whereas its role in gene expression regulation in the Basidiomycota species remains poorly understood. Here, we identified and investigated the role of cre1 in Coprinopsis cinerea, a basidiomycete model mushroom that can efficiently degrade lignocellulosic plant wastes. We used a rapid and efficient gene deletion approach based on PCR-amplified split-marker DNA cassettes together with in vitro assembled Cas9-guide RNA ribonucleoproteins (Cas9 RNPs) to generate C. cinerea cre1 gene deletion strains. Gene expression profiling of two independent C. cinerea cre1 mutants showed significant deregulation of carbohydrate metabolism, plant cell wall degrading enzymes (PCWDEs), plasma membrane transporter-related and several transcription factor-encoding genes, among others. Our results support the notion that, like reports in the ascomycetes, Cre1 of C. cinerea orchestrates CCR through a combined regulation of diverse genes, including PCWDEs, transcription factors that positively regulate PCWDEs, and membrane transporters which could import simple sugars that can induce the expression of PWCDEs. Somewhat paradoxically, though in accordance with other Agaricomycetes, genes related to lignin degradation were mostly downregulated in cre1 mutants, indicating they fall under different regulation than other PCWDEs. The gene deletion approach and the data presented here will expand our knowledge of CCR in the Basidiomycota and provide functional hypotheses on genes related to plant biomass degradation. IMPORTANCE Mushroom-forming fungi include some of the most efficient lignocellulosic plant biomass degraders. They degrade dead plant materials by a battery of lignin-, cellulose-, hemicellulose-, and pectin-degrading enzymes, the encoding genes of which are under tight transcriptional control. One of the highest-level regulations of these metabolic enzymes is known as carbon catabolite repression, which is orchestrated by the transcription factor Cre1, and ensures that costly lignocellulose-degrading enzyme genes are expressed only when simple carbon sources (e.g., glucose) are not available. Here, we identified the Cre1 ortholog in a litter decomposer Agaricomycete, Coprinopsis cinerea, knocked it out, and characterized transcriptional changes in the mutants. We identified several dozen lignocellulolytic enzyme genes as well as membrane transporters and other transcription factors as putative target genes of C. cinerea cre1. These results extend knowledge on carbon catabolite repression to litter decomposer Basidiomycota.
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Affiliation(s)
- Manish Pareek
- Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - Botond Hegedüs
- Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - Zhihao Hou
- Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - Árpád Csernetics
- Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - Hongli Wu
- Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - Máté Virágh
- Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - Neha Sahu
- Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - Xiao-Bin Liu
- Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - László Nagy
- Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
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The Transcription Factor Roc1 Is a Key Regulator of Cellulose Degradation in the Wood-Decaying Mushroom
Schizophyllum commune. mBio 2022; 13:e0062822. [PMID: 35604096 PMCID: PMC9239231 DOI: 10.1128/mbio.00628-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Wood-degrading fungi in the phylum Basidiomycota play a crucial role in nutrient recycling by breaking down all components of wood. Fungi have evolved transcriptional networks that regulate expression of wood-degrading enzymes, allowing them to prioritize one nutrient source over another.
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8
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Chroumpi T, Martínez-Reyes N, Kun RS, Peng M, Lipzen A, Ng V, Tejomurthula S, Zhang Y, Grigoriev IV, Mäkelä MR, de Vries RP, Garrigues S. Detailed analysis of the D-galactose catabolic pathways in Aspergillus niger reveals complexity at both metabolic and regulatory level. Fungal Genet Biol 2022; 159:103670. [PMID: 35121171 DOI: 10.1016/j.fgb.2022.103670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 12/22/2021] [Accepted: 01/28/2022] [Indexed: 01/23/2023]
Abstract
The current impetus towards a sustainable bio-based economy has accelerated research to better understand the mechanisms through which filamentous fungi convert plant biomass, a valuable feedstock for biotechnological applications. Several transcription factors have been reported to control the polysaccharide degradation and metabolism of the resulting sugars in fungi. However, little is known about their individual contributions, interactions and crosstalk. D-galactose is a hexose sugar present mainly in hemicellulose and pectin in plant biomass. Here, we study D-galactose conversion by Aspergillus niger and describe the involvement of the arabinanolytic and xylanolytic activators AraR and XlnR, in addition to the D-galactose-responsive regulator GalX. Our results deepen the understanding of the complexity of the filamentous fungal regulatory network for plant biomass degradation and sugar catabolism, and facilitate the generation of more efficient plant biomass-degrading strains for biotechnological applications.
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Affiliation(s)
- Tania Chroumpi
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Natalia Martínez-Reyes
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Roland S Kun
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Mao Peng
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Anna Lipzen
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
| | - Vivian Ng
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
| | - Sravanthi Tejomurthula
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
| | - Yu Zhang
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
| | - Igor V Grigoriev
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States; Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, United States
| | - Miia R Mäkelä
- Department of Microbiology, P.O. Box 56, Viikinkaari 9, University of Helsinki, Helsinki, Finland
| | - Ronald P de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands.
| | - Sandra Garrigues
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
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9
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Mohamed RA, Ren K, Mou YN, Ying SH, Feng MG. Genome-Wide Insight into Profound Effect of Carbon Catabolite Repressor (Cre1) on the Insect-Pathogenic Lifecycle of Beauveriabassiana. J Fungi (Basel) 2021; 7:jof7110895. [PMID: 34829184 PMCID: PMC8622151 DOI: 10.3390/jof7110895] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 11/16/2022] Open
Abstract
Carbon catabolite repression (CCR) is critical for the preferential utilization of glucose derived from environmental carbon sources and regulated by carbon catabolite repressor A (Cre1/CreA) in filamentous fungi. However, a role of Cre1-mediated CCR in insect-pathogenic fungal utilization of host nutrients during normal cuticle infection (NCI) and hemocoel colonization remains explored insufficiently. Here, we report an indispensability of Cre1 for Beauveriabassiana's utilization of nutrients in insect integument and hemocoel. Deletion of cre1 resulted in severe defects in radial growth on various media, hypersensitivity to oxidative stress, abolished pathogenicity via NCI or intrahemocoel injection (cuticle-bypassing infection) but no change in conidial hydrophobicity and adherence to insect cuticle. Markedly reduced biomass accumulation in the Δcre1 cultures was directly causative of severe defect in aerial conidiation and reduced secretion of various cuticle-degrading enzymes. The majority (1117) of 1881 dysregulated genes identified from the Δcre1 versus wild-type cultures were significantly downregulated, leading to substantial repression of many enriched function terms and pathways, particularly those involved in carbon and nitrogen metabolisms, cuticle degradation, antioxidant response, cellular transport and homeostasis, and direct/indirect gene mediation. These findings offer a novel insight into profound effect of Cre1 on the insect-pathogenic lifestyle of B. bassiana.
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10
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Huang L, Li X, Dong L, Wang B, Pan L. Profiling of chromatin accessibility identifies transcription factor binding sites across the genome of Aspergillus species. BMC Biol 2021; 19:189. [PMID: 34488759 PMCID: PMC8419926 DOI: 10.1186/s12915-021-01114-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 08/02/2021] [Indexed: 12/30/2022] Open
Abstract
Background The identification of open chromatin regions and transcription factor binding sites (TFBs) is an important step in understanding the regulation of gene expression in diverse species. ATAC-seq is a technique used for such purpose by providing high-resolution measurements of chromatin accessibility revealed through integration of Tn5 transposase. However, the existence of cell walls in filamentous fungi and associated difficulty in purifying nuclei have precluded the routine application of this technique, leading to a lack of experimentally determined and computationally inferred data on the identity of genome-wide cis-regulatory elements (CREs) and TFBs. In this study, we constructed an ATAC-seq platform suitable for filamentous fungi and generated ATAC-seq libraries of Aspergillus niger and Aspergillus oryzae grown under a variety of conditions. Results We applied the ATAC-seq assay for filamentous fungi to delineate the syntenic orthologue and differentially changed chromatin accessibility regions among different Aspergillus species, during different culture conditions, and among specific TF-deleted strains. The syntenic orthologues of accessible regions were responsible for the conservative functions across Aspergillus species, while regions differentially changed between culture conditions and TFs mutants drove differential gene expression programs. Importantly, we suggest criteria to determine TFBs through the analysis of unbalanced cleavage of distinct TF-bound DNA strands by Tn5 transposase. Based on this criterion, we constructed data libraries of the in vivo genomic footprint of A. niger under distinct conditions, and generated a database of novel transcription factor binding motifs through comparison of footprints in TF-deleted strains. Furthermore, we validated the novel TFBs in vivo through an artificial synthetic minimal promoter system. Conclusions We characterized the chromatin accessibility regions of filamentous fungi species, and identified a complete TFBs map by ATAC-seq, which provides valuable data for future analyses of transcriptional regulation in filamentous fungi. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01114-0.
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Affiliation(s)
- Lianggang Huang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China
| | - Xuejie Li
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China
| | - Liangbo Dong
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China
| | - Bin Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China. .,Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China.
| | - Li Pan
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China. .,Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou, 510006, China.
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11
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Gabriel R, Mueller R, Floerl L, Hopson C, Harth S, Schuerg T, Fleissner A, Singer SW. CAZymes from the thermophilic fungus Thermoascus aurantiacus are induced by C5 and C6 sugars. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:169. [PMID: 34384463 PMCID: PMC8359064 DOI: 10.1186/s13068-021-02018-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/02/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Filamentous fungi are excellent lignocellulose degraders, which they achieve through producing carbohydrate active enzymes (CAZymes). CAZyme production is highly orchestrated and gene expression analysis has greatly expanded understanding of this important biotechnological process. The thermophilic fungus Thermoascus aurantiacus secretes highly active thermostable enzymes that enable saccharifications at higher temperatures; however, the genome-wide measurements of gene expression in response to CAZyme induction are not understood. RESULTS A fed-batch system with plant biomass-derived sugars D-xylose, L-arabinose and cellobiose established that these sugars induce CAZyme expression in T. aurantiacus. The C5 sugars induced both cellulases and hemicellulases, while cellobiose specifically induced cellulases. A minimal medium formulation was developed to enable gene expression studies of T. aurantiacus with these inducers. It was found that d-xylose and L-arabinose strongly induced a wide variety of CAZymes, auxiliary activity (AA) enzymes and carbohydrate esterases (CEs), while cellobiose facilitated lower expression of mostly cellulase genes. Furthermore, putative orthologues of different unfolded protein response genes were up-regulated during the C5 sugar feeding together with genes in the C5 sugar assimilation pathways. CONCLUSION This work has identified two additional CAZyme inducers for T. aurantiacus, L-arabinose and cellobiose, along with D-xylose. A combination of biochemical assays and RNA-seq measurements established that C5 sugars induce a suite of cellulases and hemicellulases, providing paths to produce broad spectrum thermotolerant enzymatic mixtures.
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Affiliation(s)
- Raphael Gabriel
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 9720, USA
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Institut Für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany
| | - Rebecca Mueller
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 9720, USA
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Institut Für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany
| | - Lena Floerl
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 9720, USA
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences Vienna (BOKU), Muthgasse 18, 1190, Vienna, Austria
- Laboratory of Food Systems Biotechnology, Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Cynthia Hopson
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 9720, USA
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Department of Chemical Engineering and Materials, Faculty of Chemistry, Complutense University of Madrid, Av. Complutense s/n, 28040, Madrid, Spain
| | - Simon Harth
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 9720, USA
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Frankfurt Institute of Molecular Biosciences, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
| | - Timo Schuerg
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 9720, USA
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
| | - Andre Fleissner
- Institut Für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany
- Braunschweig Integrated Centre of Systems Biology (BRICS), Rebenring 56, 38106, Braunschweig, Germany
| | - Steven W Singer
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 9720, USA.
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.
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12
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Tanaka M, Gomi K. Induction and Repression of Hydrolase Genes in Aspergillus oryzae. Front Microbiol 2021; 12:677603. [PMID: 34108952 PMCID: PMC8180590 DOI: 10.3389/fmicb.2021.677603] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 04/26/2021] [Indexed: 11/13/2022] Open
Abstract
The filamentous fungus Aspergillus oryzae, also known as yellow koji mold, produces high levels of hydrolases such as amylolytic and proteolytic enzymes. This property of producing large amounts of hydrolases is one of the reasons why A. oryzae has been used in the production of traditional Japanese fermented foods and beverages. A wide variety of hydrolases produced by A. oryzae have been used in the food industry. The expression of hydrolase genes is induced by the presence of certain substrates, and various transcription factors that regulate such expression have been identified. In contrast, in the presence of glucose, the expression of the glycosyl hydrolase gene is generally repressed by carbon catabolite repression (CCR), which is mediated by the transcription factor CreA and ubiquitination/deubiquitination factors. In this review, we present the current knowledge on the regulation of hydrolase gene expression, including CCR, in A. oryzae.
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Affiliation(s)
- Mizuki Tanaka
- Biomolecular Engineering Laboratory, School of Food and Nutritional Science, University of Shizuoka, Shizuoka, Japan
| | - Katsuya Gomi
- Laboratory of Fermentation Microbiology, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
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13
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Carbon Catabolite Repression Governs Diverse Physiological Processes and Development in Aspergillus nidulans. mBio 2021; 13:e0373421. [PMID: 35164551 PMCID: PMC8844935 DOI: 10.1128/mbio.03734-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Carbon catabolite repression (CCR) is a common phenomenon of microorganisms that enable efficient utilization of carbon nutrients, critical for the fitness of microorganisms in the wild and for pathogenic species to cause infection. In most filamentous fungal species, the conserved transcription factor CreA/Cre1 mediates CCR. Previous studies demonstrated a primary function for CreA/Cre1 in carbon metabolism; however, the phenotype of creA/cre1 mutants indicated broader roles. The global function and regulatory mechanism of this wide-domain transcription factor has remained elusive. Here, we applied two powerful genomics methods (transcriptome sequencing and chromatin immunoprecipitation sequencing) to delineate the direct and indirect roles of Aspergillus nidulans CreA across diverse physiological processes, including secondary metabolism, iron homeostasis, oxidative stress response, development, N-glycan biosynthesis, unfolded protein response, and nutrient and ion transport. The results indicate intricate connections between the regulation of carbon metabolism and diverse cellular functions. Moreover, our work also provides key mechanistic insights into CreA regulation and identifies CreA as a master regulator controlling many transcription factors of different regulatory networks. The discoveries for this highly conserved transcriptional regulator in a model fungus have important implications for CCR in related pathogenic and industrial species. IMPORTANCE The ability to scavenge and use a wide range of nutrients for growth is crucial for microorganisms' survival in the wild. Carbon catabolite repression (CCR) is a transcriptional regulatory phenomenon of both bacteria and fungi to coordinate the expression of genes required for preferential utilization of carbon sources. Since carbon metabolism is essential for growth, CCR is central to the fitness of microorganisms. In filamentous fungi, CCR is mediated by the conserved transcription factor CreA/Cre1, whose function in carbon metabolism has been well established. However, the global roles and regulatory mechanism of CreA/Cre1 are poorly defined. This study uncovers the direct and indirect functions of CreA in the model organism Aspergillus nidulans over diverse physiological processes and development and provides mechanistic insights into how CreA controls different regulatory networks. The work also reveals an interesting functional divergence between filamentous fungal and yeast CreA/Cre1 orthologues.
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14
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Comprehensive analysis of the dermatophyte Trichophyton rubrum transcriptional profile reveals dynamic metabolic modulation. Biochem J 2020; 477:873-885. [PMID: 32022226 DOI: 10.1042/bcj20190868] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 02/03/2020] [Accepted: 02/05/2020] [Indexed: 01/21/2023]
Abstract
The environmental challenges imposed onto fungal pathogens require a dynamic metabolic modulation, which relies on activation or repression of critical factors and is essential for the establishment and perpetuation of host infection. Wherefore, to overcome the different host microenvironments, pathogens not only depend on virulence factors but also on metabolic flexibility, which ensures their dynamic response to stress conditions in the host. Here, we evaluate Trichophyton rubrum interaction with keratin from a metabolic perspective. We present information about gene modulation of the dermatophyte during early infection stage after shifting from glucose- to keratin-containing culture media, in relation to its use of glucose as the carbon source. Analyzing T. rubrum transcriptome using high-throughput RNA-sequencing technology, we identified the modulation of essential genes related to nitrogen, fatty acid, ergosterol, and carbohydrate metabolisms, among a myriad of other genes necessary for the growth of T. rubrum in keratinized tissues. Our results provide reliable and critical strategies for adaptation to keratin and confirm that the urea-degrading activity associated with the reduction in disulfide bonds and proteolytic activity facilitated keratin degradation. The global modulation orchestrates the responses that support virulence and the proper adaptation to keratin compared with glucose as the carbon source. The gene expression profiling of the host-pathogen interaction highlights candidate genes involved in fungal adaptation and survival and elucidates the machinery required for the establishment of the initial stages of infection.
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15
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de Assis LJ, Silva LP, Liu L, Schmitt K, Valerius O, Braus GH, Ries LNA, Goldman GH. The High Osmolarity Glycerol Mitogen-Activated Protein Kinase regulates glucose catabolite repression in filamentous fungi. PLoS Genet 2020; 16:e1008996. [PMID: 32841242 PMCID: PMC7473523 DOI: 10.1371/journal.pgen.1008996] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/04/2020] [Accepted: 07/15/2020] [Indexed: 12/22/2022] Open
Abstract
The utilization of different carbon sources in filamentous fungi underlies a complex regulatory network governed by signaling events of different protein kinase pathways, including the high osmolarity glycerol (HOG) and protein kinase A (PKA) pathways. This work unraveled cross-talk events between these pathways in governing the utilization of preferred (glucose) and non-preferred (xylan, xylose) carbon sources in the reference fungus Aspergillus nidulans. An initial screening of a library of 103 non-essential protein kinase (NPK) deletion strains identified several mitogen-activated protein kinases (MAPKs) to be important for carbon catabolite repression (CCR). We selected the MAPKs Ste7, MpkB, and PbsA for further characterization and show that they are pivotal for HOG pathway activation, PKA activity, CCR via regulation of CreA cellular localization and protein accumulation, as well as for hydrolytic enzyme secretion. Protein-protein interaction studies show that Ste7, MpkB, and PbsA are part of the same protein complex that regulates CreA cellular localization in the presence of xylan and that this complex dissociates upon the addition of glucose, thus allowing CCR to proceed. Glycogen synthase kinase (GSK) A was also identified as part of this protein complex and shown to potentially phosphorylate two serine residues of the HOG MAPKK PbsA. This work shows that carbon source utilization is subject to cross-talk regulation by protein kinases of different signaling pathways. Furthermore, this study provides a model where the correct integration of PKA, HOG, and GSK signaling events are required for the utilization of different carbon sources. Filamentous fungi secrete an array of biotechnologically valuable enzymes, with enzyme production being inhibited in the presence of preferred carbon sources, such as glucose, in a process known as carbon catabolite repression (CCR). This work unravels upstream signalling events that regulate CCR in Aspergillus nidulans. Different mitogen-activated protein kinases (MAPKs) were identified and shown to be crucial for CCR and protein kinase A (PKA) activity, which is essential for carbon source utilisation in filamentous fungi. Furthermore, the MAPKs formed a protein complex with additional protein kinases, such as glycogen synthase kinase (GSK), which is important for glucose metabolism; resulting in the inhibition of CCR in the presence of non-preferred carbon sources. GSK was shown to potentially phosphorylate the MAPK PbsA of the high osmolarity glycerol (HOG) pathway. This study thus unravels the cross-talk between protein kinases from different signalling pathways that regulate carbon source utilisation in filamentous fungi.
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Affiliation(s)
- Leandro José de Assis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Bloco Q, Universidade de São Paulo, Brazil
| | - Lilian Pereira Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Bloco Q, Universidade de São Paulo, Brazil
| | - Li Liu
- Department of Molecular Microbiology and Genetics and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
| | - Kerstin Schmitt
- Department of Molecular Microbiology and Genetics and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
| | - Oliver Valerius
- Department of Molecular Microbiology and Genetics and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
| | - Gerhard H. Braus
- Department of Molecular Microbiology and Genetics and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
- * E-mail: (GHB); (LNAR); (GHG)
| | - Laure Nicolas Annick Ries
- Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brazil
- * E-mail: (GHB); (LNAR); (GHG)
| | - Gustavo Henrique Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Bloco Q, Universidade de São Paulo, Brazil
- Institute for Advanced Study, Technical University of Munich, Garching, Germany
- * E-mail: (GHB); (LNAR); (GHG)
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16
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Chudzicka-Ormaniec P, Macios M, Koper M, Weedall GD, Caddick MX, Weglenski P, Dzikowska A. The role of the GATA transcription factor AreB in regulation of nitrogen and carbon metabolism in Aspergillus nidulans. FEMS Microbiol Lett 2020; 366:5426211. [PMID: 30939206 PMCID: PMC6494665 DOI: 10.1093/femsle/fnz066] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 04/01/2019] [Indexed: 11/13/2022] Open
Abstract
In Aspergillus nidulans, nitrogen and carbon metabolism are under the control of wide-domain regulatory systems, including nitrogen metabolite repression, carbon catabolite repression and the nutrient starvation response. Transcriptomic analysis of the wild type strain grown under different combinations of carbon and nitrogen regimes was performed, to identify differentially regulated genes. Carbon metabolism predominates as the most important regulatory signal but for many genes, both carbon and nitrogen metabolisms coordinate regulation. To identify mechanisms coordinating nitrogen and carbon metabolism, we tested the role of AreB, previously identified as a regulator of genes involved in nitrogen metabolism. Deletion of areB has significant phenotypic effects on the utilization of specific carbon sources, confirming its role in the regulation of carbon metabolism. AreB was shown to regulate the expression of areA, tamA, creA, xprG and cpcA regulatory genes suggesting areB has a range of indirect, regulatory effects. Different isoforms of AreB are produced as a result of differential splicing and use of two promoters which are differentially regulated by carbon and nitrogen conditions. These isoforms are likely to be functionally distinct and thus contributing to the modulation of AreB activity.
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Affiliation(s)
- Patrycja Chudzicka-Ormaniec
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, ul. Pawińskiego 5A, 02-106 Warsaw, Poland
| | - Maria Macios
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, ul. Pawińskiego 5A, 02-106 Warsaw, Poland
| | - Michał Koper
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, ul. Pawińskiego 5A, 02-106 Warsaw, Poland
| | - Gareth D Weedall
- Institute of Integrative Biology, The University of Liverpool, Biosciences Building, Crown Street, Liverpool L69 7ZB, UK.,School of Natural Sciences and Psychology, Liverpool John Moores University, James Parsons Building, Byrom Street, Liverpool L3 3AF, UK
| | - Mark X Caddick
- Institute of Integrative Biology, The University of Liverpool, Biosciences Building, Crown Street, Liverpool L69 7ZB, UK
| | - Piotr Weglenski
- Centre of New Technologies, University of Warsaw, ul. Żwirki i Wigury 93, 02-089 Warsaw, Poland.,Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawińskiego 5A, 02-106 Warsaw, Poland
| | - Agnieszka Dzikowska
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, ul. Pawińskiego 5A, 02-106 Warsaw, Poland.,Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawińskiego 5A, 02-106 Warsaw, Poland
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17
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Exploiting the potential of metal and solvent tolerant laccase from Tricholoma giganteum AGDR1 for the removal of pesticides. Int J Biol Macromol 2019; 144:586-595. [PMID: 31830449 DOI: 10.1016/j.ijbiomac.2019.12.068] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/21/2019] [Accepted: 12/09/2019] [Indexed: 11/22/2022]
Abstract
Laccase from previously reported hardwood degrading fungus, Tricholoma giganteum AGDR1, was isolated, identified at molecular level, biochemically characterized and also utilized for pesticide degradation. Laccase gene is comprised of 3752 bp, which encompassed 742-bp of 5' flanking upstream sequence with 12 introns and 12 exons. Mature enzyme possesses 391 amino acids and signal peptide, which is determined to be monomeric protein with an apparent molecular weight of 41 kDa and 6.45 pI. Higher optimal activities were observed at 45 °C and pH 3.0 and surprisingly, it exhibited more than 20% of relative activity at pH 1.5. Purified laccase was tolerant to 100 mM of metals (i.e. Se, Pb, Cu, Cr and Cd), organic solvents (ethyl acetate, methanol, ethanol and acetone) and potent inhibitors (hydroxylamine, thiourea, NaF and Na-azide) as compared to reported laccases. It was able to degrade 29%, 7% and 72% of chlorpyrifos, profenofos and thiophanate methyl within 15 h, respectively. Molecular docking analysis revealed that higher binding efficacy of these pesticides is observed with H83, H320, A95, V384, and P366 which are presented near to the catalytic site. Based on the results, T. giganteum AGDR1 laccase can be applied for the potential remediation and industrial applications under harsh conditions.
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18
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Vassiliadis D, Wong KH, Andrianopoulos A, Monahan BJ. A genome-wide analysis of carbon catabolite repression in Schizosaccharomyces pombe. BMC Genomics 2019; 20:251. [PMID: 30922219 PMCID: PMC6440086 DOI: 10.1186/s12864-019-5602-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 03/12/2019] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Optimal glucose metabolism is central to the growth and development of cells. In microbial eukaryotes, carbon catabolite repression (CCR) mediates the preferential utilization of glucose, primarily by repressing alternate carbon source utilization. In fission yeast, CCR is mediated by transcriptional repressors Scr1 and the Tup/Ssn6 complex, with the Rst2 transcription factor important for activation of gluconeogenesis and sexual differentiation genes upon derepression. Through genetic and genome-wide methods, this study aimed to comprehensively characterize CCR in fission yeast by identifying the genes and biological processes that are regulated by Scr1, Tup/Ssn6 and Rst2, the core CCR machinery. RESULTS The transcriptional response of fission yeast to glucose-sufficient or glucose-deficient growth conditions in wild type and CCR mutant cells was determined by RNA-seq and ChIP-seq. Scr1 was found to regulate genes involved in carbon metabolism, hexose uptake, gluconeogenesis and the TCA cycle. Surprisingly, a role for Scr1 in the suppression of sexual differentiation was also identified, as homothallic scr1 deletion mutants showed ectopic meiosis in carbon and nitrogen rich conditions. ChIP-seq characterised the targets of Tup/Ssn6 and Rst2 identifying regulatory roles within and independent of CCR. Finally, a subset of genes bound by all three factors was identified, implying that regulation of certain loci may be modulated in a competitive fashion between the Scr1, Tup/Ssn6 repressors and the Rst2 activator. CONCLUSIONS By identifying the genes directly and indirectly regulated by Scr1, Tup/Ssn6 and Rst2, this study comprehensively defined the gene regulatory networks of CCR in fission yeast and revealed the transcriptional complexities governing this system.
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Affiliation(s)
- Dane Vassiliadis
- Genetics, Genomics & Systems Biology, School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia. .,Commonwealth Scientific and Industrial Research Organisation (CSIRO), Parkville, Victoria, Australia.
| | - Koon Ho Wong
- Faculty of Health Sciences, University of Macau, Macau, China.,Institute of Translational Medicine, University of Macau, Macau, China
| | - Alex Andrianopoulos
- Genetics, Genomics & Systems Biology, School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Brendon J Monahan
- Genetics, Genomics & Systems Biology, School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia. .,Commonwealth Scientific and Industrial Research Organisation (CSIRO), Parkville, Victoria, Australia. .,Cancer Therapeutics (CTx), Parkville, Victoria, Australia.
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19
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Mäkelä MR, Aguilar-Pontes MV, van Rossen-Uffink D, Peng M, de Vries RP. The fungus Aspergillus niger consumes sugars in a sequential manner that is not mediated by the carbon catabolite repressor CreA. Sci Rep 2018; 8:6655. [PMID: 29703914 PMCID: PMC5923239 DOI: 10.1038/s41598-018-25152-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 04/17/2018] [Indexed: 11/09/2022] Open
Abstract
In nature, the fungus Aspergillus niger degrades plant biomass polysaccharides to monomeric sugars, transports them into its cells, and uses catabolic pathways to convert them into biochemical building blocks and energy. We show that when grown in liquid cultures, A. niger takes up plant-biomass derived sugars in a largely sequential manner. Interestingly, this sequential uptake was not mediated by the fungal general carbon catabolite repressor protein CreA. Furthermore, transcriptome analysis strongly indicated that the preferential use of the monomeric sugars is arranged at the level of transport, but it is not reflected in transcriptional regulation of sugar catabolism. Therefore, the results indicate that the regulation of sugar transport and catabolism are separate processes in A. niger.
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Affiliation(s)
- Miia R Mäkelä
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands.,Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - María Victoria Aguilar-Pontes
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - Diana van Rossen-Uffink
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - Mao Peng
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands
| | - Ronald P de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands. .,Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland.
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20
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Adnan M, Zheng W, Islam W, Arif M, Abubakar YS, Wang Z, Lu G. Carbon Catabolite Repression in Filamentous Fungi. Int J Mol Sci 2017; 19:ijms19010048. [PMID: 29295552 PMCID: PMC5795998 DOI: 10.3390/ijms19010048] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Revised: 12/13/2017] [Accepted: 12/20/2017] [Indexed: 12/18/2022] Open
Abstract
Carbon Catabolite Repression (CCR) has fascinated scientists and researchers around the globe for the past few decades. This important mechanism allows preferential utilization of an energy-efficient and readily available carbon source over relatively less easily accessible carbon sources. This mechanism helps microorganisms to obtain maximum amount of glucose in order to keep pace with their metabolism. Microorganisms assimilate glucose and highly favorable sugars before switching to less-favored sources of carbon such as organic acids and alcohols. In CCR of filamentous fungi, CreA acts as a transcription factor, which is regulated to some extent by ubiquitination. CreD-HulA ubiquitination ligase complex helps in CreA ubiquitination, while CreB-CreC deubiquitination (DUB) complex removes ubiquitin from CreA, which causes its activation. CCR of fungi also involves some very crucial elements such as Hexokinases, cAMP, Protein Kinase (PKA), Ras proteins, G protein-coupled receptor (GPCR), Adenylate cyclase, RcoA and SnfA. Thorough study of molecular mechanism of CCR is important for understanding growth, conidiation, virulence and survival of filamentous fungi. This review is a comprehensive revision of the regulation of CCR in filamentous fungi as well as an updated summary of key regulators, regulation of different CCR-dependent mechanisms and its impact on various physical characteristics of filamentous fungi.
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Affiliation(s)
- Muhammad Adnan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- Key Laboratory of Bio-Pesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Wenhui Zheng
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- Key Laboratory of Bio-Pesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Waqar Islam
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Muhammad Arif
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Yakubu Saddeeq Abubakar
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- Key Laboratory of Bio-Pesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Zonghua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- Key Laboratory of Bio-Pesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Guodong Lu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- Key Laboratory of Bio-Pesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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21
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Benocci T, Aguilar-Pontes MV, Zhou M, Seiboth B, de Vries RP. Regulators of plant biomass degradation in ascomycetous fungi. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:152. [PMID: 28616076 PMCID: PMC5468973 DOI: 10.1186/s13068-017-0841-x] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/06/2017] [Indexed: 05/05/2023]
Abstract
Fungi play a major role in the global carbon cycle because of their ability to utilize plant biomass (polysaccharides, proteins, and lignin) as carbon source. Due to the complexity and heterogenic composition of plant biomass, fungi need to produce a broad range of degrading enzymes, matching the composition of (part of) the prevalent substrate. This process is dependent on a network of regulators that not only control the extracellular enzymes that degrade the biomass, but also the metabolic pathways needed to metabolize the resulting monomers. This review will summarize the current knowledge on regulation of plant biomass utilization in fungi and compare the differences between fungal species, focusing in particular on the presence or absence of the regulators involved in this process.
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Affiliation(s)
- Tiziano Benocci
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Maria Victoria Aguilar-Pontes
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Miaomiao Zhou
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Bernhard Seiboth
- Research Area Biochemical Technology, Institute of Chemical and Biological Engineering, TU Wien, 1060 Vienna, Austria
| | - Ronald P. de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
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Fountain JC, Bajaj P, Pandey M, Nayak SN, Yang L, Kumar V, Jayale AS, Chitikineni A, Zhuang W, Scully BT, Lee RD, Kemerait RC, Varshney RK, Guo B. Oxidative stress and carbon metabolism influence Aspergillus flavus transcriptome composition and secondary metabolite production. Sci Rep 2016; 6:38747. [PMID: 27941917 PMCID: PMC5150527 DOI: 10.1038/srep38747] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 11/15/2016] [Indexed: 11/09/2022] Open
Abstract
Contamination of crops with aflatoxin is a serious global threat to food safety. Aflatoxin production by Aspergillus flavus is exacerbated by drought stress in the field and by oxidative stress in vitro. We examined transcriptomes of three toxigenic and three atoxigenic isolates of A. flavus in aflatoxin conducive and non-conducive media with varying levels of H2O2 to investigate the relationship of secondary metabolite production, carbon source, and oxidative stress. We found that toxigenic and atoxigenic isolates employ distinct mechanisms to remediate oxidative damage, and that carbon source affected the isolates’ expression profiles. Iron metabolism, monooxygenases, and secondary metabolism appeared to participate in isolate oxidative responses. The results suggest that aflatoxin and aflatrem biosynthesis may remediate oxidative stress by consuming excess oxygen and that kojic acid production may limit iron-mediated, non-enzymatic generation of reactive oxygen species. Together, secondary metabolite production may enhance A. flavus stress tolerance, and may be reduced by enhancing host plant tissue antioxidant capacity though genetic improvement by breeding selection.
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Affiliation(s)
- Jake C Fountain
- Department of Plant Pathology, University of Georgia, Tifton, GA, USA.,USDA-ARS Crop Protection and Management Research Unit, Tifton, GA, USA
| | - Prasad Bajaj
- International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana, India
| | - Manish Pandey
- International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana, India
| | - Spurthi N Nayak
- International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana, India
| | - Liming Yang
- Department of Plant Pathology, University of Georgia, Tifton, GA, USA.,USDA-ARS Crop Protection and Management Research Unit, Tifton, GA, USA
| | - Vinay Kumar
- International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana, India
| | - Ashwin S Jayale
- International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana, India
| | - Anu Chitikineni
- International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana, India
| | - Weijian Zhuang
- Fujian Agricultural and Forestry University, Fuzhou, Fujian, China
| | - Brian T Scully
- USDA-ARS US Horticultural Research Laboratory, Fort Pierce, FL, USA
| | - R Dewey Lee
- Department of Crop and Soil Sciences, University of Georgia, Tifton, GA, USA
| | - Robert C Kemerait
- Department of Plant Pathology, University of Georgia, Tifton, GA, USA
| | - Rajeev K Varshney
- International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana, India
| | - Baozhu Guo
- USDA-ARS Crop Protection and Management Research Unit, Tifton, GA, USA
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23
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Alam MA, Kelly JM. Proteins interacting with CreA and CreB in the carbon catabolite repression network in Aspergillus nidulans. Curr Genet 2016; 63:669-683. [PMID: 27915380 DOI: 10.1007/s00294-016-0667-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/22/2016] [Accepted: 11/23/2016] [Indexed: 11/26/2022]
Abstract
In Aspergillus nidulans, carbon catabolite repression (CCR) is mediated by the global repressor protein CreA. The deubiquitinating enzyme CreB is a component of the CCR network. Genetic interaction was confirmed using a strain containing complete loss-of-function alleles of both creA and creB. No direct physical interaction was identified between tagged versions of CreA and CreB. To identify any possible protein(s) that may form a bridge between CreA and CreB, we purified both proteins from mycelia grown in media that result in repression or derepression. The purified proteins were analysed by LC/MS and identified using MaxQuant and Mascot databases. For both CreA and CreB, 47 proteins were identified in repressing and derepressing conditions. Orthologues of the co-purified proteins were identified in S. cerevisiae and humans. Gene ontology analyses of A. nidulans proteins and yeast and human orthologues were performed. Functional annotation analysis revealed that proteins that preferentially interact with CreA in repressing conditions include histones and histone transcription regulator 3 (Hir3). Proteins interacting with CreB tend to be involved in cellular transportation and organization. Similar findings were obtained using yeast and human orthologues, although the yeast background generated a number of other biological processes involving Mig1p which were not present in the A. nidulans or human background analyses. Hir3 was present in repressing conditions for CreA and in both growth conditions for CreB, suggesting that Hir3, or proteins interacting with Hir3, could be a possible target of CreB.
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Affiliation(s)
- Md Ashiqul Alam
- Department of Genetics and Evolution, The University of Adelaide, Adelaide, 5005, SA, Australia
| | - Joan M Kelly
- Department of Genetics and Evolution, The University of Adelaide, Adelaide, 5005, SA, Australia.
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24
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The CreB deubiquitinating enzyme does not directly target the CreA repressor protein in Aspergillus nidulans. Curr Genet 2016; 63:647-667. [DOI: 10.1007/s00294-016-0666-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/23/2016] [Accepted: 08/24/2016] [Indexed: 12/12/2022]
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25
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Cambri G, de Sousa MML, Fonseca DDM, Marchini FK, da Silveira JLM, Paba J. Analysis of the Biotechnological Potential of a Lentinus crinitus Isolate in the Light of Its Secretome. J Proteome Res 2016; 15:4557-4568. [DOI: 10.1021/acs.jproteome.6b00636] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Geison Cambri
- Departamento
de Bioquímica, Setor de Ciências Biológicas,
Centro Politécnico, Universidade Federal do Paraná, 81531-990 Curitiba-PR, Brazil
| | - Mirta Mittelstedt Leal de Sousa
- Department
of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, NTNU, N-7491 Trondheim, Norway
| | - Davi de Miranda Fonseca
- Department
of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, NTNU, N-7491 Trondheim, Norway
- Proteomics
and Metabolomics Core Facility (PROMEC), Norwegian University of Science and Technology, NTNU, N-7491 Trondheim, Norway
| | - Fabricio K. Marchini
- Laboratório
de Genômica Funcional, Instituto Carlos Chagas, Fundação Oswaldo Cruz, 81350-010 Curitiba-PR, Brazil
| | - Joana Lea Meira da Silveira
- Departamento
de Bioquímica, Setor de Ciências Biológicas,
Centro Politécnico, Universidade Federal do Paraná, 81531-990 Curitiba-PR, Brazil
| | - Jaime Paba
- Departamento
de Bioquímica, Setor de Ciências Biológicas,
Centro Politécnico, Universidade Federal do Paraná, 81531-990 Curitiba-PR, Brazil
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26
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Alam MA, Kamlangdee N, Kelly JM. The CreB deubiquitinating enzyme does not directly target the CreA repressor protein in Aspergillus nidulans. Curr Genet 2016:10.1007/s00294-016-0643-x. [PMID: 27589970 DOI: 10.1007/s00294-016-0643-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/23/2016] [Accepted: 08/24/2016] [Indexed: 11/25/2022]
Abstract
Ubiquitination/deubiquitination pathways are now recognized as key components of gene regulatory mechanisms in eukaryotes. The major transcriptional repressor for carbon catabolite repression in Aspergillus nidulans is CreA, and mutational analysis led to the suggestion that a regulatory ubiquitination/deubiquitination pathway is involved. A key unanswered question is if and how this pathway, comprising CreB (deubiquitinating enzyme) and HulA (ubiquitin ligase) and other proteins, is involved in the regulatory mechanism. Previously, missense alleles of creA and creB were analysed for genetic interactions, and here we extended this to complete loss-of-function alleles of creA and creB, and compared morphological and biochemical phenotypes, which confirmed genetic interaction between the genes. We investigated whether CreA, or a protein in a complex with it, is a direct target of the CreB deubiquitination enzyme, using co-purifications of CreA and CreB, first using strains that overexpress the proteins and then using strains that express the proteins from their native promoters. The Phos-tag system was used to show that CreA is a phosphorylated protein, but no ubiquitination was detected using anti-ubiquitin antibodies and Western analysis. These findings were confirmed using mass spectrometry, which confirmed that CreA was differentially phosphorylated but not ubiquitinated. Thus, CreA is not a direct target of CreB, and nor are proteins that form part of a stable complex with CreA a target of CreB. These results open up new questions regarding the molecular mechanism of CreA repressing activity, and how the ubiquitination pathway involving CreB interacts with this regulatory network.
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Affiliation(s)
- Md Ashiqul Alam
- Department of Genetics and Evolution, The University of Adelaide, Adelaide, 5005, Australia
| | - Niyom Kamlangdee
- Department of Genetics and Evolution, The University of Adelaide, Adelaide, 5005, Australia
- Walailak University, 222 Thaiburi Thasala, Nakhonsithamrat, Nakhon Si Thammarat, 80160, Thailand
| | - Joan M Kelly
- Department of Genetics and Evolution, The University of Adelaide, Adelaide, 5005, Australia.
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27
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Brown NA, Ries LNA, Reis TF, Rajendran R, Corrêa dos Santos RA, Ramage G, Riaño-Pachón DM, Goldman GH. RNAseq reveals hydrophobins that are involved in the adaptation of Aspergillus nidulans to lignocellulose. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:145. [PMID: 27437031 PMCID: PMC4950808 DOI: 10.1186/s13068-016-0558-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Accepted: 06/24/2016] [Indexed: 05/28/2023]
Abstract
BACKGROUND Sugarcane is one of the world's most profitable crops. Waste steam-exploded sugarcane bagasse (SEB) is a cheap, abundant, and renewable lignocellulosic feedstock for the next-generation biofuels. In nature, fungi seldom exist as planktonic cells, similar to those found in the nutrient-rich environment created within an industrial fermenter. Instead, fungi predominantly form biofilms that allow them to thrive in hostile environments. RESULTS In turn, we adopted an RNA-sequencing approach to interrogate how the model fungus, Aspergillus nidulans, adapts to SEB, revealing the induction of carbon starvation responses and the lignocellulolytic machinery, in addition to morphological adaptations. Genetic analyses showed the importance of hydrophobins for growth on SEB. The major hydrophobin, RodA, was retained within the fungal biofilm on SEB fibres. The StuA transcription factor that regulates fungal morphology was up-regulated during growth on SEB and controlled hydrophobin gene induction. The absence of the RodA or DewC hydrophobins reduced biofilm formation. The loss of a RodA or a functional StuA reduced the retention of the hydrolytic enzymes within the vicinity of the fungus. Hence, hydrophobins promote biofilm formation on SEB, and may enhance lignocellulose utilisation via promoting a compact substrate-enzyme-fungus structure. CONCLUSION This novel study highlights the importance of hydrophobins to the formation of biofilms and the efficient deconstruction of lignocellulose.
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Affiliation(s)
- Neil Andrew Brown
- />Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire UK
| | - Laure N. A. Ries
- />Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Thaila F. Reis
- />Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Ranjith Rajendran
- />Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, The University of Glasgow, Glasgow, UK
| | - Renato Augusto Corrêa dos Santos
- />Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, Campinas, SP CEP 13083-970 Brazil
| | - Gordon Ramage
- />Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, The University of Glasgow, Glasgow, UK
| | - Diego Mauricio Riaño-Pachón
- />Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, Campinas, SP CEP 13083-970 Brazil
| | - Gustavo H. Goldman
- />Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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28
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Diverse Regulation of the CreA Carbon Catabolite Repressor in Aspergillus nidulans. Genetics 2016; 203:335-52. [PMID: 27017621 DOI: 10.1534/genetics.116.187872] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 03/15/2016] [Indexed: 12/31/2022] Open
Abstract
Carbon catabolite repression (CCR) is a process that selects the energetically most favorable carbon source in an environment. CCR represses the use of less favorable carbon sources when a better source is available. Glucose is the preferential carbon source for most microorganisms because it is rapidly metabolized, generating quick energy for growth. In the filamentous fungus Aspergillus nidulans, CCR is mediated by the transcription factor CreA, a C2H2 finger domain DNA-binding protein. The aim of this work was to investigate the regulation of CreA and characterize its functionally distinct protein domains. CreA depends in part on de novo protein synthesis and is regulated in part by ubiquitination. CreC, the scaffold protein in the CreB-CreC deubiquitination (DUB) complex, is essential for CreA function and stability. Deletion of select protein domains in CreA resulted in persistent nuclear localization and target gene repression. A region in CreA conserved between Aspergillus spp. and Trichoderma reesei was identified as essential for growth on various carbon, nitrogen, and lipid sources. In addition, a role of CreA in amino acid transport and nitrogen assimilation was observed. Taken together, these results indicate previously unidentified functions of this important transcription factor. These novel functions serve as a basis for additional research in fungal carbon metabolism with the potential aim to improve fungal industrial applications.
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29
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Kiesenhofer D, Mach-Aigner AR, Mach RL. Understanding the Mechanism of Carbon Catabolite Repression to Increase Protein Production in Filamentous Fungi. Fungal Biol 2016. [DOI: 10.1007/978-3-319-27951-0_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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30
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Soyer JL, Hamiot A, Ollivier B, Balesdent MH, Rouxel T, Fudal I. The APSES transcription factor LmStuA is required for sporulation, pathogenic development and effector gene expression in Leptosphaeria maculans. MOLECULAR PLANT PATHOLOGY 2015; 16:1000-5. [PMID: 25727237 PMCID: PMC6638475 DOI: 10.1111/mpp.12249] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Leptosphaeria maculans causes stem canker of oilseed rape (Brassica napus). The APSES transcription factor StuA is a key developmental regulator of fungi, involved in morphogenesis, conidia production and also more recently described as required for secondary metabolite production and for effector gene expression in phytopathogenic fungi. We investigated the involvement of the orthologue of StuA in L. maculans, LmStuA, in morphogenesis, pathogenicity and effector gene expression. LmStuA is induced during mycelial growth and at 14 days after infection, corresponding to the development of pycnidia on oilseed rape leaves, consistent with the function of StuA described so far. We set up the functional characterization of LmStuA using an RNA interference approach. Silenced LmStuA transformants showed typical phenotypic defects of StuA mutants with altered growth in axenic culture and impaired conidia production and perithecia formation. Silencing of LmStuA abolished the pathogenicity of L. maculans on oilseed rape leaves and also resulted in a drastic decrease in expression of at least three effector genes during in planta infection, suggesting either that LmStuA regulates, directly or indirectly, the expression of several effector genes in L. maculans or that the infection stage in which effectors are expressed is not reached when LmStuA expression is silenced.
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Affiliation(s)
- Jessica L Soyer
- INRA, UMR 1290 INRA-AgroParisTech BIOGER, Avenue Lucien Brétignières, F-78850, Thiverval-Grignon, France
| | - Audrey Hamiot
- INRA, UMR 1290 INRA-AgroParisTech BIOGER, Avenue Lucien Brétignières, F-78850, Thiverval-Grignon, France
| | - Bénédicte Ollivier
- INRA, UMR 1290 INRA-AgroParisTech BIOGER, Avenue Lucien Brétignières, F-78850, Thiverval-Grignon, France
| | - Marie-Hélène Balesdent
- INRA, UMR 1290 INRA-AgroParisTech BIOGER, Avenue Lucien Brétignières, F-78850, Thiverval-Grignon, France
| | - Thierry Rouxel
- INRA, UMR 1290 INRA-AgroParisTech BIOGER, Avenue Lucien Brétignières, F-78850, Thiverval-Grignon, France
| | - Isabelle Fudal
- INRA, UMR 1290 INRA-AgroParisTech BIOGER, Avenue Lucien Brétignières, F-78850, Thiverval-Grignon, France
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31
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Gilbert MK, Mack BM, Wei Q, Bland JM, Bhatnagar D, Cary JW. RNA sequencing of an nsdC mutant reveals global regulation of secondary metabolic gene clusters in Aspergillus flavus. Microbiol Res 2015; 182:150-61. [PMID: 26686623 DOI: 10.1016/j.micres.2015.08.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 08/21/2015] [Accepted: 08/31/2015] [Indexed: 01/16/2023]
Abstract
The filamentous fungus, Aspergillus flavus (A. flavus) is an opportunistic pathogen capable of invading a number of crops and contaminating them with toxic secondary metabolites such as aflatoxins. Characterizing the molecular mechanisms governing growth and development of this organism is vital for developing safe and effective strategies for reducing crop contamination. The transcription factor nsdC has been identified as being required for normal asexual development and aflatoxin production in A. flavus. Building on a previous study using a large (L)-sclerotial morphotype A. flavus nsdC mutant we observed alterations in conidiophore development and loss of sclerotial and aflatoxin production using a nsdC mutant of a small (S)-sclerotial morphotype, that normally produces aflatoxin and sclerotia in quantities much higher than the L-morphotype. RNA sequencing analysis of the nsdC knockout mutant and isogenic control strain identified a number of differentially expressed genes related to development and production of secondary metabolites, including aflatoxin, penicillin and aflatrem. Further, RNA-seq data indicating down regulation of aflatrem biosynthetic gene expression in the nsdC mutant correlated with HPLC analyses showing a decrease in aflatrem levels. The current study expands the role of nsdC as a globally acting transcription factor that is a critical regulator of both asexual reproduction and secondary metabolism in A. flavus.
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Affiliation(s)
- Matthew K Gilbert
- USDA, ARS, Southern Regional Research Center 1100 Robert E Lee Blvd., New Orleans, LA 70124, USA
| | - Brian M Mack
- USDA, ARS, Southern Regional Research Center 1100 Robert E Lee Blvd., New Orleans, LA 70124, USA
| | - Qijian Wei
- USDA, ARS, Southern Regional Research Center 1100 Robert E Lee Blvd., New Orleans, LA 70124, USA
| | - John M Bland
- USDA, ARS, Southern Regional Research Center 1100 Robert E Lee Blvd., New Orleans, LA 70124, USA
| | - Deepak Bhatnagar
- USDA, ARS, Southern Regional Research Center 1100 Robert E Lee Blvd., New Orleans, LA 70124, USA
| | - Jeffrey W Cary
- USDA, ARS, Southern Regional Research Center 1100 Robert E Lee Blvd., New Orleans, LA 70124, USA.
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32
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An H, Wei D, Xiao T. Transcriptional profiles of laccase genes in the brown rot fungus Postia placenta MAD-R-698. J Microbiol 2015; 53:606-15. [DOI: 10.1007/s12275-015-4705-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 06/16/2015] [Accepted: 06/23/2015] [Indexed: 10/23/2022]
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33
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Cupertino FB, Virgilio S, Freitas FZ, Candido TDS, Bertolini MC. Regulation of glycogen metabolism by the CRE-1, RCO-1 and RCM-1 proteins in Neurospora crassa. The role of CRE-1 as the central transcriptional regulator. Fungal Genet Biol 2015; 77:82-94. [PMID: 25889113 DOI: 10.1016/j.fgb.2015.03.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/30/2015] [Accepted: 03/31/2015] [Indexed: 11/17/2022]
Abstract
The transcription factor CreA/Mig1/CRE-1 is a repressor protein that regulates the use of alternative carbon sources via a mechanism known as Carbon Catabolite Repression (CCR). In Saccharomyces cerevisiae, Mig1 recruits the complex Ssn6-Tup1, the Neurospora crassa RCM-1 and RCO-1 orthologous proteins, respectively, to bind to promoters of glucose-repressible genes. We have been studying the regulation of glycogen metabolism in N. crassa and the identification of the RCO-1 corepressor as a regulator led us to investigate the regulatory role of CRE-1 in this process. Glycogen content is misregulated in the rco-1(KO), rcm-1(RIP) and cre-1(KO) strains, and the glycogen synthase phosphorylation is decreased in all strains, showing that CRE-1, RCO-1 and RCM-1 proteins are involved in glycogen accumulation and in the regulation of GSN activity by phosphorylation. We also confirmed the regulatory role of CRE-1 in CCR and its nuclear localization under repressing condition in N. crassa. The expression of all glycogenic genes is misregulated in the cre-1(KO) strain, suggesting that CRE-1 also controls glycogen metabolism by regulating gene expression. The existence of a high number of the Aspergillus nidulans CreA motif (5'-SYGGRG-3') in the glycogenic gene promoters led us to analyze the binding of CRE-1 to some DNA motifs both in vitro by DNA gel shift and in vivo by ChIP-qPCR analysis. CRE-1 bound in vivo to all motifs analyzed demonstrating that it down-regulates glycogen metabolism by controlling gene expression and GSN phosphorylation.
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Affiliation(s)
- Fernanda Barbosa Cupertino
- Departamento de Bioquímica e Tecnologia Química, Instituto de Química, Universidade Estadual Paulista, UNESP, 14800-060 Araraquara, SP, Brazil
| | - Stela Virgilio
- Departamento de Bioquímica e Tecnologia Química, Instituto de Química, Universidade Estadual Paulista, UNESP, 14800-060 Araraquara, SP, Brazil
| | - Fernanda Zanolli Freitas
- Departamento de Bioquímica e Tecnologia Química, Instituto de Química, Universidade Estadual Paulista, UNESP, 14800-060 Araraquara, SP, Brazil
| | - Thiago de Souza Candido
- Departamento de Bioquímica e Tecnologia Química, Instituto de Química, Universidade Estadual Paulista, UNESP, 14800-060 Araraquara, SP, Brazil
| | - Maria Célia Bertolini
- Departamento de Bioquímica e Tecnologia Química, Instituto de Química, Universidade Estadual Paulista, UNESP, 14800-060 Araraquara, SP, Brazil.
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34
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Sloothaak J, Odoni DI, de Graaff LH, Martins dos Santos VAP, Schaap PJ, Tamayo-Ramos JA. Aspergillus niger membrane-associated proteome analysis for the identification of glucose transporters. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:150. [PMID: 26388937 PMCID: PMC4574540 DOI: 10.1186/s13068-015-0317-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 08/18/2015] [Indexed: 05/07/2023]
Abstract
BACKGROUND The development of biological processes that replace the existing petrochemical-based industry is one of the biggest challenges in biotechnology. Aspergillus niger is one of the main industrial producers of lignocellulolytic enzymes, which are used in the conversion of lignocellulosic feedstocks into fermentable sugars. Both the hydrolytic enzymes responsible for lignocellulose depolymerisation and the molecular mechanisms controlling their expression have been well described, but little is known about the transport systems for sugar uptake in A. niger. Understanding the transportome of A. niger is essential to achieve further improvements at strain and process design level. Therefore, this study aims to identify and classify A. niger sugar transporters, using newly developed tools for in silico and in vivo analysis of its membrane-associated proteome. RESULTS In the present research work, a hidden Markov model (HMM), that shows a good performance in the identification and segmentation of functionally validated glucose transporters, was constructed. The model (HMMgluT) was used to analyse the A. niger membrane-associated proteome response to high and low glucose concentrations at a low pH. By combining the abundance patterns of the proteins found in the A. niger plasmalemma proteome with their HMMgluT scores, two new putative high-affinity glucose transporters, denoted MstG and MstH, were identified. MstG and MstH were functionally validated and biochemically characterised by heterologous expression in a S. cerevisiae glucose transport null mutant. They were shown to be a high-affinity glucose transporter (K m = 0.5 ± 0.04 mM) and a very high-affinity glucose transporter (K m = 0.06 ± 0.005 mM), respectively. CONCLUSIONS This study, focusing for the first time on the membrane-associated proteome of the industrially relevant organism A. niger, shows the global response of the transportome to the availability of different glucose concentrations. Analysis of the A. niger transportome with the newly developed HMMgluT showed to be an efficient approach for the identification and classification of new glucose transporters.
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Affiliation(s)
- J. Sloothaak
- Laboratory of Systems and Synthetic Biology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - D. I. Odoni
- Laboratory of Systems and Synthetic Biology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - L. H. de Graaff
- Laboratory of Systems and Synthetic Biology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - V. A. P. Martins dos Santos
- Laboratory of Systems and Synthetic Biology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - P. J. Schaap
- Laboratory of Systems and Synthetic Biology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - J. A. Tamayo-Ramos
- Laboratory of Systems and Synthetic Biology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
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de Assis LJ, Ries LNA, Savoldi M, dos Reis TF, Brown NA, Goldman GH. Aspergillus nidulans protein kinase A plays an important role in cellulase production. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:213. [PMID: 26690721 PMCID: PMC4683954 DOI: 10.1186/s13068-015-0401-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 11/30/2015] [Indexed: 05/17/2023]
Abstract
BACKGROUND The production of bioethanol from lignocellulosic feedstocks is dependent on lignocellulosic biomass degradation by hydrolytic enzymes. The main component of lignocellulose is cellulose and different types of organisms are able to secrete cellulases. The filamentous fungus Aspergillus nidulans serves as a model organism to study cellulase production and the available tools allow exploring more in depth the mechanisms governing cellulase production and carbon catabolite repression. RESULTS In A. nidulans, microarray data identified the cAMP-dependent protein kinase A (PkaA) as being involved in the transcriptional modulation and the production of lignocellulolytic enzymes in the presence of cellulose. Deletion of pkaA resulted in increased hydrolytic enzyme secretion, but reduced growth in the presence of lignocellulosic components and various other carbon sources. Furthermore, genes involved in fungal development were increased in the ΔpkaA strain, probably leading to the increased hyphal branching as was observed in this strain. This would allow the secretion of higher amounts of proteins. In addition, the expression of SynA, encoding a V-SNARE synaptobrevin protein involved in secretion, was increased in the ΔpkaA mutant. Deletion of pkaA also resulted in the reduced nuclear localization of the carbon catabolite repressor CreA in the presence of glucose and in partial de-repression when grown on cellulose. PkaA is involved in the glucose signaling pathway as the absence of this protein resulted in reduced glucose uptake and lower hexokinase/glucokinase activity, directing the cell to starvation conditions. Genome-wide transcriptomics showed that the expression of genes encoding proteins involved in fatty acid metabolism, mitochondrial function and in the use of cell storages was increased. CONCLUSIONS This study shows that PkaA is involved in hydrolytic enzyme production in A. nidulans. It appears that this protein kinase blocks the glucose pathway, hence forcing the cell to change to starvation conditions, increasing hydrolytic enzyme secretion and inducing the usage of cellular storages. This work uncovered new regulatory avenues governing the tight interplay between the metabolic states of the cell, which are important for the production of hydrolytic enzymes targeting lignocellulosic biomass. Deletion of pkaA resulted in a strain with increased hydrolytic enzyme secretion and reduced biomass formation.
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Affiliation(s)
- Leandro José de Assis
- />Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil
| | - Laure Nicolas Annick Ries
- />Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil
| | - Marcela Savoldi
- />Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil
| | - Thaila Fernanda dos Reis
- />Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil
| | - Neil Andrew Brown
- />Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts AL5 2JQ UK
| | - Gustavo Henrique Goldman
- />Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil
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Madhavan S, Krause K, Jung EM, Kothe E. Differential regulation of multi-copper oxidases in Schizophyllum commune during sexual development. Mycol Prog 2014. [DOI: 10.1007/s11557-014-1009-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ming Y, Wei Q, Jin K, Xia Y. MaSnf1, a sucrose non-fermenting protein kinase gene, is involved in carbon source utilization, stress tolerance, and virulence in Metarhizium acridum. Appl Microbiol Biotechnol 2014; 98:10153-64. [PMID: 25213916 DOI: 10.1007/s00253-014-6066-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 08/29/2014] [Accepted: 08/30/2014] [Indexed: 10/24/2022]
Abstract
The protein kinase sucrose non-fermenting-1(Snf1) regulates the derepression of glucose-repressible genes and plays a major role in carbon source utilization. In this study, MaSnf1, a sucrose non-fermenting protein kinase gene, has been identified from the entomopathogenic fungus Metarhizium acridum, which has a great potential as a biocontrol agent. The functions of MaSnf1 were characterized using gene disruption and complementation strategies. Disruption of MaSnf1 reduced the conidial yield and delayed the conidial germination on potato dextrose agar (PDA) medium. MaSnf1 is also important for response to ultraviolet radiation and heat shock stress and carbon source utilization in M. acridum. Bioassays by topical inoculation and intrahemocoel injection showed that the MaSnf1 deletion mutant exhibited greatly reduced pathogenicity. The reduced expression level of chitinase gene (Chi) and protease gene (Pr1A) in MaSnf1-disruption transformant (ΔMaSnf1) most likely affects the initial penetration into its host. Additionally, the reduced expression level of acidic trehalase gene (ATM1) probably causes a decline in growth rate in insect hemolymph. Inactivation of MaSnf1 led to a significant decrease in virulence, probably owing to reduction in conidial germination, and appressorium formation, impairment in penetration, and decrease in growth rate in insect hemolymph.
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Affiliation(s)
- Yue Ming
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, 400045, People's Republic of China
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Kowalczyk JE, Benoit I, de Vries RP. Regulation of plant biomass utilization in Aspergillus. ADVANCES IN APPLIED MICROBIOLOGY 2014; 88:31-56. [PMID: 24767425 DOI: 10.1016/b978-0-12-800260-5.00002-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The ability of fungi to survive in every known biotope, both natural and man-made, relies in part on their ability to use a wide range of carbon sources. Fungi degrade polymeric carbon sources present in the environment (polysaccharides, proteins, and lignins) to use the monomeric components as nutrients. However, the available carbon sources vary strongly in nature, both between biotopes and in time. The degradation of polymeric carbon sources is mediated through the production of a broad range of enzymes, the production of which is tightly controlled by a network of regulators and linked to the activation of catabolic pathways to convert the released monomers. This review summarizes the knowledge of Aspergillus regulators involved in plant biomass utilization.
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Affiliation(s)
| | - Isabelle Benoit
- CBS-KNAW Fungal Biodiversity Centre, Utrecht, The Netherlands
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Martins I, Hartmann DO, Alves PC, Martins C, Garcia H, Leclercq CC, Ferreira R, He J, Renaut J, Becker JD, Silva Pereira C. Elucidating how the saprophytic fungus Aspergillus nidulans uses the plant polyester suberin as carbon source. BMC Genomics 2014; 15:613. [PMID: 25043916 PMCID: PMC4117967 DOI: 10.1186/1471-2164-15-613] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 07/16/2014] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Lipid polymers in plant cell walls, such as cutin and suberin, build recalcitrant hydrophobic protective barriers. Their degradation is of foremost importance for both plant pathogenic and saprophytic fungi. Regardless of numerous reports on fungal degradation of emulsified fatty acids or cutin, and on fungi-plant interactions, the pathways involved in the degradation and utilisation of suberin remain largely overlooked. As a structural component of the plant cell wall, suberin isolation, in general, uses harsh depolymerisation methods that destroy its macromolecular structure. We recently overcame this limitation isolating suberin macromolecules in a near-native state. RESULTS Suberin macromolecules were used here to analyse the pathways involved in suberin degradation and utilisation by Aspergillus nidulans. Whole-genome profiling data revealed the complex degrading enzymatic machinery used by this saprophytic fungus. Initial suberin modification involved ester hydrolysis and ω-hydroxy fatty acid oxidation that released long chain fatty acids. These fatty acids were processed through peroxisomal β-oxidation, leading to up-regulation of genes encoding the major enzymes of these pathways (e.g. faaB and aoxA). The obtained transcriptome data was further complemented by secretome, microscopic and spectroscopic analyses. CONCLUSIONS Data support that during fungal growth on suberin, cutinase 1 and some lipases (e.g. AN8046) acted as the major suberin degrading enzymes (regulated by FarA and possibly by some unknown regulatory elements). Suberin also induced the onset of sexual development and the boost of secondary metabolism.
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Affiliation(s)
- Isabel Martins
- />Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Diego O Hartmann
- />Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Paula C Alves
- />Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Celso Martins
- />Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
- />Instituto de Biologia Experimental e Tecnológica (iBET), Av. da República, 2781-901 Oeiras, Portugal
| | - Helga Garcia
- />Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Céline C Leclercq
- />Proteomics Platform, Centre de Recherche Public - Gabriel Lippmann, Belvaux, Luxembourg
| | - Rui Ferreira
- />Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Ji He
- />Cancer Genomics Research Laboratory, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, (previously, the Scientific Computing department, Samuel Roberts Noble Foundation, USA, 8717 Grovemont Circle, 20877 Gaithersburg, MD USA
| | - Jenny Renaut
- />Proteomics Platform, Centre de Recherche Public - Gabriel Lippmann, Belvaux, Luxembourg
| | - Jörg D Becker
- />Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal
| | - Cristina Silva Pereira
- />Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
- />Instituto de Biologia Experimental e Tecnológica (iBET), Av. da República, 2781-901 Oeiras, Portugal
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BbSNF1 contributes to cell differentiation, extracellular acidification, and virulence in Beauveria bassiana, a filamentous entomopathogenic fungus. Appl Microbiol Biotechnol 2014; 98:8657-73. [DOI: 10.1007/s00253-014-5907-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 06/07/2014] [Accepted: 06/15/2014] [Indexed: 01/23/2023]
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Brown NA, Ries LNA, Goldman GH. How nutritional status signalling coordinates metabolism and lignocellulolytic enzyme secretion. Fungal Genet Biol 2014; 72:48-63. [PMID: 25011009 DOI: 10.1016/j.fgb.2014.06.012] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 06/26/2014] [Accepted: 06/28/2014] [Indexed: 11/30/2022]
Abstract
The utilisation of lignocellulosic plant biomass as an abundant, renewable feedstock for green chemistries and biofuel production is inhibited by its recalcitrant nature. In the environment, lignocellulolytic fungi are naturally capable of breaking down plant biomass into utilisable saccharides. Nonetheless, within the industrial context, inefficiencies in the production of lignocellulolytic enzymes impede the implementation of green technologies. One of the primary causes of such inefficiencies is the tight transcriptional control of lignocellulolytic enzymes via carbon catabolite repression. Fungi coordinate metabolism, protein biosynthesis and secretion with cellular energetic status through the detection of intra- and extra-cellular nutritional signals. An enhanced understanding of the signals and signalling pathways involved in regulating the transcription, translation and secretion of lignocellulolytic enzymes is therefore of great biotechnological interest. This comparative review describes how nutrient sensing pathways regulate carbon catabolite repression, metabolism and the utilisation of alternative carbon sources in Saccharomyces cerevisiae and ascomycete fungi.
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Affiliation(s)
- Neil Andrew Brown
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil.
| | | | - Gustavo Henrique Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil; Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Campinas, Brazil.
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[Mechanisms and regulation of enzymatic hydrolysis of cellulose in filamentous fungi: classical cases and new models]. Rev Iberoam Micol 2014; 32:1-12. [PMID: 24607657 DOI: 10.1016/j.riam.2013.10.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 09/25/2013] [Accepted: 10/23/2013] [Indexed: 11/21/2022] Open
Abstract
Cellulose is the most abundant renewable carbon source on earth. However, this polymer structure comprises a physical and chemical barrier for carbon access, which has limited its exploitation. In nature, only a few percentage of microorganisms may degrade this polymer by cellulase expression. Filamentous fungi are one of the most active and efficient groups among these microorganisms. This review describes similarities and differences between cellulase activity mechanisms and regulatory mechanisms controlling gene expression for 3 of the most studied cellulolytic filamentous fungi models: Trichoderma reesei, Aspergillus niger and Aspergillus nidulans, and the recently described model Neurospora crassa. Unlike gene expression mechanisms, it was found that enzymatic activity mechanisms are similar for all the studied models. Understanding the distinctive elements of each system is essential for the development of strategies for the improvement of cellulase production, either by providing the optimum environment (fermentation conditions) or increasing gene expression in these microorganisms by genetic engineering.
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Luo Z, Qin Y, Pei Y, Keyhani NO. Ablation of thecreAregulator results in amino acid toxicity, temperature sensitivity, pleiotropic effects on cellular development and loss of virulence in the filamentous fungusBeauveria bassiana. Environ Microbiol 2014; 16:1122-36. [DOI: 10.1111/1462-2920.12352] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 12/01/2013] [Indexed: 12/16/2022]
Affiliation(s)
- Zhibing Luo
- Biotechnology Research Center; Southwest University; Chongqing China
- Department of Microbiology and Cell Science; University of Florida; Bldg 981, Museum Rd. Gainesville FL 32611 USA
| | - Yuqi Qin
- Department of Microbiology and Cell Science; University of Florida; Bldg 981, Museum Rd. Gainesville FL 32611 USA
| | - Yan Pei
- Biotechnology Research Center; Southwest University; Chongqing China
| | - Nemat O. Keyhani
- Department of Microbiology and Cell Science; University of Florida; Bldg 981, Museum Rd. Gainesville FL 32611 USA
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44
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Mello-de-Sousa TM, Gorsche R, Rassinger A, Poças-Fonseca MJ, Mach RL, Mach-Aigner AR. A truncated form of the Carbon catabolite repressor 1 increases cellulase production in Trichoderma reesei. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:129. [PMID: 25342970 PMCID: PMC4173072 DOI: 10.1186/s13068-014-0129-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 08/22/2014] [Indexed: 05/22/2023]
Abstract
BACKGROUND Rut-C30 is a cellulase-hyperproducing Trichoderma reesei strain and, consequently, became the ancestor of most industry strains used in the production of plant cell wall-degrading enzymes, in particular cellulases. Due to three rounds of undirected mutagenesis its genetic background differs from the wild-type QM6a in many ways, of which two are the lack of a 83 kb large sequence in scaffold 15 and the partial lack of the gene encoding the Carbon catabolite repressor 1 (CREI). However, it is still unclear, what exactly enhances cellulase production in Rut-C30. RESULTS The investigation of the expression of two genes encoding cellulases (cbh1 and cbh2) and the gene encoding their main transactivator (xyr1) revealed that the presence of the truncated form of CREI (CREI-96) contributes more to the Rut-C30 phenotype than a general loss of CREI-mediated carbon catabolite repression (cre1 deletion strain) or the deletion of 29 genes encoded in the scaffold 15 (83 kb deletion strain). We found that the remaining cre1 in Rut-C30 (cre1-96) is transcribed into mRNA, that its putative gene product (Cre1-96) is still able to bind DNA, and that the CREI-binding sites in the upstream regulatory regions of the chosen CREI-target genes are still protected in Rut-C30. As it was previously reported that CREI acts on the nucleosome positioning, we also analyzed chromatin accessibility of the core promoters of CREI-target genes and found them open even on D-glucose in the presence of CREI-96. CONCLUSIONS The lack of the full version of CREI in Rut-C30 corresponds with a partial release from carbon catabolite repression but is not completely explained by the lack of CREI. In contrast, the truncated CREI-96 of Rut-C30 exerts a positive regulatory influence on the expression of target genes. Mechanistically this might be explained at least partially by a CREI-96-mediated opening of chromatin.
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Affiliation(s)
- Thiago M Mello-de-Sousa
- />Department for Biotechnology and Microbiology, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorfer Str. 1a, A-1060 Wien, Austria
| | - Rita Gorsche
- />Department for Biotechnology and Microbiology, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorfer Str. 1a, A-1060 Wien, Austria
| | - Alice Rassinger
- />Department for Biotechnology and Microbiology, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorfer Str. 1a, A-1060 Wien, Austria
| | - Marcio J Poças-Fonseca
- />Department of Genetics and Morphology, Institute of Biological Sciences, University of Brasília, Campus Universitário Darcy Ribeiro, 70910-900 Brasília, DF Brazil
| | - Robert L Mach
- />Department for Biotechnology and Microbiology, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorfer Str. 1a, A-1060 Wien, Austria
| | - Astrid R Mach-Aigner
- />Department for Biotechnology and Microbiology, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorfer Str. 1a, A-1060 Wien, Austria
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Influence of carbohydrates on secondary metabolism in Fusarium avenaceum. Toxins (Basel) 2013; 5:1655-63. [PMID: 24064720 PMCID: PMC3798878 DOI: 10.3390/toxins5091655] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 09/16/2013] [Accepted: 09/16/2013] [Indexed: 01/07/2023] Open
Abstract
Fusarium avenaceum is a widespread pathogen of important crops in the temperate climate zones that can produce many bioactive secondary metabolites, including moniliformin, fusarin C, antibiotic Y, 2-amino-14,16-dimethyloctadecan-3-ol (2-AOD-3-ol), chlamydosporol, aurofusarin and enniatins. Here, we examine the production of these secondary metabolites in response to cultivation on different carbon sources in order to gain insight into the regulation and production of secondary metabolites in F. avenaceum. Seven monosaccharides (arabinose, xylose, fructose, sorbose, galactose, mannose, glucose), five disaccharides (cellobiose, lactose, maltose, sucrose and trehalose) and three polysaccharides (dextrin, inulin and xylan) were used as substrates. Three F. avenaceum strains were used in the experiments. These were all able to grow and produce aurofusarin on the tested carbon sources. Moniliformin and enniatins were produced on all carbon types, except on lactose, which suggest a common conserved regulation mechanism. Differences in the strains was observed for production of fusarin C, 2-AOD-3-ol, chlamydosporol and antibiotic Y, which suggests that carbon source plays a role in the regulation of their biosynthesis.
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Brown NA, de Gouvea PF, Krohn NG, Savoldi M, Goldman GH. Functional characterisation of the non-essential protein kinases and phosphatases regulating Aspergillus nidulans hydrolytic enzyme production. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:91. [PMID: 23800192 PMCID: PMC3698209 DOI: 10.1186/1754-6834-6-91] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 06/18/2013] [Indexed: 05/06/2023]
Abstract
BACKGROUND Despite recent advances in the understanding of lignocellulolytic enzyme regulation, less is known about how different carbon sources are sensed and the signaling cascades that result in the adaptation of cellular metabolism and hydrolase secretion. Therefore, the role played by non-essential protein kinases (NPK) and phosphatases (NPP) in the sensing of carbon and/or energetic status was investigated in the model filamentous fungus Aspergillus nidulans. RESULTS Eleven NPKs and seven NPPs were identified as being involved in cellulase, and in some cases also hemicellulase, production in A. nidulans. The regulation of CreA-mediated carbon catabolite repression (CCR) in the parental strain was determined by fluorescence microscopy, utilising a CreA::GFP fusion protein. The sensing of phosphorylated glucose, via the RAS signalling pathway induced CreA repression, while carbon starvation resulted in derepression. Growth on cellulose represented carbon starvation and derepressing conditions. The involvement of the identified NPKs in the regulation of cellulose-induced responses and CreA derepression was assessed by genome-wide transcriptomics (GEO accession 47810). CreA::GFP localisation and the restoration of endocellulase activity via the introduction of the ∆creA mutation, was assessed in the NPK-deficient backgrounds. The absence of either the schA or snfA kinase dramatically reduced cellulose-induced transcriptional responses, including the expression of hydrolytic enzymes and transporters. The mechanism by which these two NPKs controlled gene transcription was identified, as the NPK-deficient mutants were not able to unlock CreA-mediated carbon catabolite repression under derepressing conditions, such as carbon starvation or growth on cellulose. CONCLUSIONS Collectively, this study identified multiple kinases and phosphatases involved in the sensing of carbon and/or energetic status, while demonstrating the overlapping, synergistic roles of schA and snfA in the regulation of CreA derepression and hydrolytic enzyme production in A. nidulans. The importance of a carbon starvation-induced signal for CreA derepression, permitting transcriptional activator binding, appeared paramount for hydrolase secretion.
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Affiliation(s)
- Neil Andrew Brown
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Paula Fagundes de Gouvea
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Nádia Graciele Krohn
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Marcela Savoldi
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Gustavo Henrique Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Campinas, Brazil
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Janusz G, Kucharzyk KH, Pawlik A, Staszczak M, Paszczynski AJ. Fungal laccase, manganese peroxidase and lignin peroxidase: gene expression and regulation. Enzyme Microb Technol 2012. [PMID: 23199732 DOI: 10.1016/j.enzmictec.2012.10.003] [Citation(s) in RCA: 190] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Extensive research efforts have been dedicated to characterizing expression of laccases and peroxidases and their regulation in numerous fungal species. Much attention has been brought to these enzymes broad substrate specificity resulting in oxidation of a variety of organic compounds which brings about possibilities of their utilization in biotechnological and environmental applications. Research attempts have resulted in increased production of both laccases and peroxidases by the aid of heterologous and homologous expression. Through analysis of promoter regions, protein expression patterns and culture conditions manipulations it was possible to compare and identify common pathways of these enzymes' production and secretion. Although laccase and peroxidase proteins have been crystallized and thoroughly analyzed, there are still a lot of questions remaining about their evolutionary origin and the physiological functions. This review describes the present understanding of promoter sequences and correlation between the observed regulatory effects on laccase, manganese peroxidase and lignin peroxidase genes transcript levels and the presence of specific response elements.
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Affiliation(s)
- Grzegorz Janusz
- Department of Biochemistry, Maria Curie-Skłodowska University, Akademicka 19 Street, 20-033 Lublin, Poland.
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Sarkar A, Funk AN, Scherlach K, Horn F, Schroeckh V, Chankhamjon P, Westermann M, Roth M, Brakhage AA, Hertweck C, Horn U. Differential expression of silent polyketide biosynthesis gene clusters in chemostat cultures of Aspergillus nidulans. J Biotechnol 2012; 160:64-71. [DOI: 10.1016/j.jbiotec.2012.01.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 01/09/2012] [Accepted: 01/17/2012] [Indexed: 01/11/2023]
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Seiboth B, Herold S, Kubicek CP. Metabolic engineering of inducer formation for cellulase and hemicellulase gene expression in Trichoderma reesei. Subcell Biochem 2012; 64:367-90. [PMID: 23080260 DOI: 10.1007/978-94-007-5055-5_18] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The filamentous fungus T. reeseiis today a paradigm for the commercial scale production of different plant cell wall degrading enzymes mainly cellulases and hemicellulases. Its enzymes have a long history of safe use in industry and well established applications are found within the pulp, paper, food, feed or textile processing industries. However, when these enzymes are to be used for the saccharification of cellulosic plant biomass to simple sugars which can be further converted to biofuels or other biorefinery products, and thus compete with chemicals produced from fossil sources, additional efforts are needed to reduce costs and maximize yield and efficiency of the produced enzyme mixtures. One approach to this end is the use of genetic engineering to manipulate the biochemical and regulatory pathways that operate during enzyme production and control enzyme yield. This review aims at a description of the state of art in this area.
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Affiliation(s)
- Bernhard Seiboth
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorferstraße 1a, 166-5, A-1060, Vienna, Austria
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Colabardini AC, Humanes AC, Gouvea PF, Savoldi M, Goldman MHS, Kress MRVZ, Bayram Ö, Oliveira JVDC, Gomes MD, Braus GH, Goldman GH. Molecular characterization of the Aspergillus nidulans fbxA encoding an F-box protein involved in xylanase induction. Fungal Genet Biol 2011; 49:130-40. [PMID: 22142781 DOI: 10.1016/j.fgb.2011.11.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 11/10/2011] [Accepted: 11/11/2011] [Indexed: 11/16/2022]
Abstract
The filamentous fungus Aspergillus nidulans has been used as a fungal model system to study the regulation of xylanase production. These genes are activated at transcriptional level by the master regulator the transcriptional factor XlnR and repressed by carbon catabolite repression (CCR) mediated by the wide-domain repressor CreA. Here, we screened a collection of 42 A. nidulans F-box deletion mutants grown either in xylose or xylan as the single carbon source in the presence of the glucose analog 2-deoxy-D-glucose, aiming to identify mutants that have deregulated xylanase induction. We were able to recognize a null mutant in a gene (fbxA) that has decreased xylanase activity and reduced xlnA and xlnD mRNA accumulation. The ΔfbxA mutant interacts genetically with creAd-30, creB15, and creC27 mutants. FbxA is a novel protein containing a functional F-box domain that binds to Skp1 from the SCF-type ligase. Blastp analysis suggested that FbxA is a protein exclusive from fungi, without any apparent homologs in higher eukaryotes. Our work emphasizes the importance of the ubiquitination in the A. nidulans xylanase induction and CCR. The identification of FbxA provides another layer of complexity to xylanase induction and CCR phenomena in filamentous fungi.
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