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Son YE, Han J, Lee KT, Park HS. Pleiotropic functions of SscA on the asexual spore of the human pathogenic fungus Aspergillus fumigatus. Mycology 2023; 15:238-254. [PMID: 38813476 PMCID: PMC11132850 DOI: 10.1080/21501203.2023.2294061] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 12/06/2023] [Indexed: 05/31/2024] Open
Abstract
Asexual spores, called conidia, are key reproductive fungal particles that enable survival in harsh environmental conditions or host systems. The conidia can infect humans, animals, and plants to cause various fungal diseases. Transcription factors, including VosA, WetA, and SscA, have key roles in conidia formation and long-term survival in Aspergillus nidulans. Herein, we report the pleiotropic functions of SscA in the conidia of the human pathogen A. fumigatus. The deletion of sscA increased conidia formation despite decreased fungal growth. Absence of sscA impaired long-term survival and reduced spore resistance to various stresses, including heat, UV, and oxidation. Transcriptomic analyses showed that SscA involved the mRNA expression of cell wall organisation-related genes. Importantly, the sscA deletion mutant conidia contained an increased amount of β-glucan and chitin compared to wild type conidia. In addition, conidial gliotoxin production was decreased in the sscA deletion strain. Overall, SscA has pleiotropic roles in conidia formation, maturation and dormancy and mycotoxin production in A. fumigatus.
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Affiliation(s)
- Ye-Eun Son
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, Republic of Korea
| | - Jiwoo Han
- Korea Zoonosis Research Institute, Jeonbuk National University, Iksan, Republic of Korea
| | - Kyung-Tae Lee
- Korea Zoonosis Research Institute, Jeonbuk National University, Iksan, Republic of Korea
| | - Hee-Soo Park
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, Republic of Korea
- Department of Integrative Biology, Kyungpook National University, Daegu, Republic of Korea
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2
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Sasse C, Bastakis E, Bakti F, Höfer AM, Zangl I, Schüller C, Köhler AM, Gerke J, Krappmann S, Finkernagel F, Harting R, Strauss J, Heimel K, Braus GH. Induction of Aspergillus fumigatus zinc cluster transcription factor OdrA/Mdu2 provides combined cellular responses for oxidative stress protection and multiple antifungal drug resistance. mBio 2023; 14:e0262823. [PMID: 37982619 PMCID: PMC10746196 DOI: 10.1128/mbio.02628-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 10/06/2023] [Indexed: 11/21/2023] Open
Abstract
IMPORTANCE An overexpression screen of 228 zinc cluster transcription factor encoding genes of A. fumigatus revealed 11 genes conferring increased tolerance to antifungal drugs. Out of these, four oxidative stress and drug tolerance transcription factor encoding odr genes increased tolerance to oxidative stress and antifungal drugs when overexpressed. This supports a correlation between oxidative stress response and antifungal drug tolerance in A. fumigatus. OdrA/Mdu2 is required for the cross-tolerance between azoles, polyenes, and oxidative stress and activates genes for detoxification. Under oxidative stress conditions or when overexpressed, OdrA/Mdu2 accumulates in the nucleus and activates detoxifying genes by direct binding at their promoters, as we describe with the mdr1 gene encoding an itraconazole specific efflux pump. Finally, this work gives new insights about drug and stress resistance in the opportunistic pathogenic fungus A. fumigatus.
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Affiliation(s)
- Christoph Sasse
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Emmanouil Bastakis
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Fruzsina Bakti
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Annalena M. Höfer
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Isabella Zangl
- Department of Applied Genetics and Cell Biology, Institute of Microbial Genetics, University of Natural Resources and Life Sciences, Vienna (BOKU), Campus, Tulln, Austria
- Core Facility Bioactive Molecules–Screening and Analysis, University of Natural Resources and Life Sciences, Vienna (BOKU), Austria
| | - Christoph Schüller
- Department of Applied Genetics and Cell Biology, Institute of Microbial Genetics, University of Natural Resources and Life Sciences, Vienna (BOKU), Campus, Tulln, Austria
- Core Facility Bioactive Molecules–Screening and Analysis, University of Natural Resources and Life Sciences, Vienna (BOKU), Austria
| | - Anna M. Köhler
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Jennifer Gerke
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Sven Krappmann
- Institute of Microbiology–Clinical Microbiology, Immunology and Hygiene, University Hospital Erlangen and Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
- Center for Infection Research (ECI) and Medical Immunology Campus Erlangen (MICE), Erlangen, Germany
| | - Florian Finkernagel
- Center for Tumor Biology and Immunology, Core Facility Bioinformatics, Philipps University, Marburg, Germany
| | - Rebekka Harting
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Joseph Strauss
- Department of Applied Genetics and Cell Biology, Institute of Microbial Genetics, University of Natural Resources and Life Sciences, Vienna (BOKU), Campus, Tulln, Austria
| | - Kai Heimel
- Department of Microbial Cell Biology, Institute of Microbiology and Genetics, Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, Göttingen, Germany
| | - Gerhard H. Braus
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
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3
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Pan X, Hao L, Yang C, Lin H, Wu D, Chen X, Zhang M, Ma D, Wang Y, Fu W, Yao Y, Wang S, Zhuang Z. SWD1 epigenetically chords fungal morphogenesis, aflatoxin biosynthesis, metabolism, and virulence of Aspergillus flavus. JOURNAL OF HAZARDOUS MATERIALS 2023; 455:131542. [PMID: 37172387 DOI: 10.1016/j.jhazmat.2023.131542] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 04/17/2023] [Accepted: 04/28/2023] [Indexed: 05/14/2023]
Abstract
As the main producer of aflatoxins, Aspergillus flavus is also one of the most important causes of invasive and non-invasive aspergillosis. Therefore, it is crucial to unravel the regulatory mechanisms of growth, metabolism, and pathogenicity of A. flavus. SWD1 is highly conserved across species for maintaining COMPASS methyltransferase activity, but the bio-function of SWD1 in A. flavus has not been explored. Through genetic analysis, this study revealed that SWD1 is involved in fungal morphogenesis and AFB1 biosynthesis by regulating the orthodox pathways through H3K4me1-3. Stresses sensitivity and crop models analysis revealed that SWD1 is a key regulator for the resistance of A. flavus to adapt to extreme adverse environments and to colonize crop kernels. It also revealed that the WD40 domain and 25 aa highly conserved sequence are indispensable for SWD1 in the regulation of mycotoxin bio-synthesis and fungal virulence. Metabolomic analysis inferred that SWD1 is crucial for the biosynthesis of numerous primary and secondary metabolites, regulates biological functions by reshaping the whole metabolic process, and may inhibit fungal virulence by inducing the apoptosis of mycelia through the inducer sphingosine. This study elucidates the epigenetic mechanism of SWD1 in regulating fungal pathogenicity and mycotoxin biosynthesis, and provides a potential novel target for controlling the virulence of A. flavus.
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Affiliation(s)
- Xiaohua Pan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Fujian Key Laboratory of Propagated Sensation along Meridian, Fujian Academy of Chinese Medical Sciences, Fuzhou 350003, China
| | - Ling Hao
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Chi Yang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Institute of Edible Mushroom, Fujian Academy of Agricultural Sciences, Fuzhou 350014, China
| | - Hong Lin
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Dandan Wu
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xuan Chen
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Mengjuan Zhang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Dongmei Ma
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yu Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Wangzhuo Fu
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yanfang Yao
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Zhenhong Zhuang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, Proteomic Research Center, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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Nowrousian M. The Role of Chromatin and Transcriptional Control in the Formation of Sexual Fruiting Bodies in Fungi. Microbiol Mol Biol Rev 2022; 86:e0010422. [PMID: 36409109 PMCID: PMC9769939 DOI: 10.1128/mmbr.00104-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Fungal fruiting bodies are complex, three-dimensional structures that arise from a less complex vegetative mycelium. Their formation requires the coordinated action of many genes and their gene products, and fruiting body formation is accompanied by major changes in the transcriptome. In recent years, numerous transcription factor genes as well as chromatin modifier genes that play a role in fruiting body morphogenesis were identified, and through research on several model organisms, the underlying regulatory networks that integrate chromatin structure, gene expression, and cell differentiation are becoming clearer. This review gives a summary of the current state of research on the role of transcriptional control and chromatin structure in fruiting body development. In the first part, insights from transcriptomics analyses are described, with a focus on comparative transcriptomics. In the second part, examples of more detailed functional characterizations of the role of chromatin modifiers and/or transcription factors in several model organisms (Neurospora crassa, Aspergillus nidulans, Sordaria macrospora, Coprinopsis cinerea, and Schizophyllum commune) that have led to a better understanding of regulatory networks at the level of chromatin structure and transcription are discussed.
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Affiliation(s)
- Minou Nowrousian
- Department of Molecular and Cellular Botany, Ruhr University Bochum, Bochum, Germany
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5
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Vaccination with Live or Heat-Killed Aspergillus fumigatus Δ sglA Conidia Fully Protects Immunocompromised Mice from Invasive Aspergillosis. mBio 2022; 13:e0232822. [PMID: 36066100 PMCID: PMC9600187 DOI: 10.1128/mbio.02328-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Aspergillus fumigatus causes invasive aspergillosis (IA) in immunocompromised patients, resulting in high mortality rates. Currently, no vaccine formulations to promote immune protection in at-risk individuals have been developed. In this work, we deleted the sterylglucosidase-encoding gene, sglA, in Aspergillus fumigatus and investigated its role in fungal virulence and host vaccine protection. The ΔsglA mutant accumulated sterylglucosides (SGs), newly studied immunomodulatory glycolipids, and exhibited reduced hyphal growth and altered compositions of cell wall polysaccharides. Interestingly, the ΔsglA mutant was avirulent in two murine models of IA and was fully eliminated from the lungs. Both corticosteroid-induced immunosuppressed and cyclophosphamide-induced leukopenic mice vaccinated with live or heat-killed ΔsglA conidia were fully protected against a lethal wild-type A. fumigatus challenge. These results highlight the potential of SG-accumulating strains as safe and promising vaccine formulations against invasive fungal infections. IMPORTANCE Infections by Aspergillus fumigatus occur by the inhalation of environmental fungal spores called conidia. We found that live mutant conidia accumulating glycolipids named sterylglucosides are not able to cause disease when injected into the lung. Interestingly, these animals are now protected against a secondary challenge with live wild-type conidia. Remarkably, protection against a secondary challenge persists even with vaccination with heat-killed mutant conidia. These results will significantly advance the field of the research and development of a safe fungal vaccine for protection against the environmental fungus A. fumigatus.
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6
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Song D, Jin Y, Shi Y, Xia Y, Peng G. The carbon catabolite repressor CreA is an essential virulence factor of Metarhizium acridum against Locusta migratoria. PEST MANAGEMENT SCIENCE 2022; 78:3676-3684. [PMID: 35613131 DOI: 10.1002/ps.7010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 05/04/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND CreA has been proved to be a core gene in asexual conidiation in Metarhizium acridum, which regulates the shift of normal conidiation and microcycle conidiation. At present, research on CreA in fungi has focused on carbon source metabolism. There is a lack of research on the effect of CreA in virulence of pathogenic fungi. RESULTS The virulence of the MaCreA disrupted strain (ΔMaCreA) for Locusta migratoria was lost by topical inoculation bioassay. The formation rate and turgor pressure of the appressoria decreased. Growth of ΔMaCreA in host hemolymph was delayed, and the number of hyphal bodies was significantly reduced. The conidial cell wall of ΔMaCreA became thicker, the mannan content decreased, and the chitin content increased significantly, and it was more sensitive to calcofluor white and Congo Red. α-1,3-Glucan and β-1,3-glucan are more exposed on the surface of ΔMaCreA conidia than on the wild type. Lmspätzle and Lmcactus, the immune response genes in the host Toll pathway, showed stronger transcriptional activities at the early stage of ΔMaCreA invasion. The phenoloxidase activity assay also showed stronger immunostimulation by ΔMaCreA in vitro. CONCLUSION The main reasons for the loss of virulence of ΔMaCreA in the topical inoculation were the reduced penetration ability of appressoria, limited growth in hemolymph and stronger insect immunostimulation of ΔMaCreA. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Dongxu Song
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, China
- Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, China
| | - Yumei Jin
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, China
- Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, China
| | - Youhui Shi
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, China
- Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, China
| | - Yuxian Xia
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, China
- Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, China
| | - Guoxiong Peng
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, China
- Chongqing Engineering Research Center for Fungal Insecticide, Chongqing, China
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7
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Song D, Cao Y, Xia Y. MaNsdD regulates conidiation negatively by inhibiting the AbaA expression required for normal conidiation in Metarhizium acridum. Environ Microbiol 2022; 24:2951-2961. [PMID: 35384250 DOI: 10.1111/1462-2920.16000] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 04/04/2022] [Indexed: 11/29/2022]
Abstract
Conidiation necessary for filamentous fungal survival and dispersal, proceeds in two fashions, namely normal conidiation through conidiophores differentiated from hyphae, and microcycle conidiation through conidial budding. Normal conidiation has been well studied whereas mechanisms underlying microcycle conidiation are still largely unknown. Here, we report that a gene (MaNsdD) homologous to NsdD in Aspergillus nidulans serves as a suppressor of normal conidiation but a positive regulator of hyphal development in Metarhizium acridum. Disruption of MaNsdD (ΔMaNsdD) resulted in microcycle conidiation and significantly descended in conidial resistance to heat while improved to UV irradiation. Transcriptomic analysis revealed that many genes involved in conidiation, cell division and cell wall formation were differentially expressed in ΔMaNsdD, and likely associated with the conidiation process. We found that a gene (MaAbaA) homologous to the core asexual development regulator AbaA in A. nidulans, was negatively controlled by MaNsdD. Disruption of MaAbaA led to the abolition of the conidiation process of M. acridum. These findings unravel a novel regulatory mechanism of microcycle conidiation, and add a knowledge to the asexual conidiation pathway of filamentous fungi.
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Affiliation(s)
- Dongxu Song
- School of Life Sciences, Chongqing University, Chongqing, 401331, China.,Chongqing Engineering Research Center for Fungal Insecticides, Chongqing, 401331, China.,Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, Chongqing, China
| | - Yueqing Cao
- School of Life Sciences, Chongqing University, Chongqing, 401331, China.,Chongqing Engineering Research Center for Fungal Insecticides, Chongqing, 401331, China.,Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, Chongqing, China
| | - Yuxian Xia
- School of Life Sciences, Chongqing University, Chongqing, 401331, China.,Chongqing Engineering Research Center for Fungal Insecticides, Chongqing, 401331, China.,Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, Chongqing, China
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8
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Seekles SJ, van Dam J, Arentshorst M, Ram AFJ. Natural Variation and the Role of Zn 2Cys 6 Transcription Factors SdrA, WarA and WarB in Sorbic Acid Resistance of Aspergillus niger. Microorganisms 2022; 10:microorganisms10020221. [PMID: 35208676 PMCID: PMC8877037 DOI: 10.3390/microorganisms10020221] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/16/2022] [Accepted: 01/18/2022] [Indexed: 02/07/2023] Open
Abstract
Weak acids, such as sorbic acid, are used as chemical food preservatives by the industry. Fungi overcome this weak-acid stress by inducing cellular responses mediated by transcription factors. In our research, a large-scale sorbic acid resistance screening was performed on 100 A. niger sensu stricto strains isolated from various sources to study strain variability in sorbic acid resistance. The minimal inhibitory concentration of undissociated (MICu) sorbic acid at pH = 4 in the MEB of the A. niger strains varies between 4.0 mM and 7.0 mM, with the average out of 100 strains being 4.8 ± 0.8 mM, when scored after 28 days. MICu values were roughly 1 mM lower when tested in commercial ice tea. Genome sequencing of the most sorbic-acid-sensitive strain among the isolates revealed a premature stop codon inside the sorbic acid response regulator encoding gene sdrA. Repairing this missense mutation increased the sorbic acid resistance, showing that the sorbic-acid-sensitive phenotype of this strain is caused by the loss of SdrA function. To identify additional transcription factors involved in weak-acid resistance, a transcription factor knock-out library consisting of 240 A. niger deletion strains was screened. The screen identified a novel transcription factor, WarB, which contributes to the resistance against a broad range of weak acids, including sorbic acid. The roles of SdrA, WarA and WarB in weak-acid resistance, including sorbic acid, were compared by creating single, double and the triple knock-out strains. All three transcription factors were found to have an additive effect on the sorbic acid stress response.
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Affiliation(s)
- Sjoerd J. Seekles
- TIFN, Agro Business Park 82, 6708 PW Wageningen, The Netherlands;
- Department Molecular Microbiology and Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands; (J.v.D.); (M.A.)
| | - Jisca van Dam
- Department Molecular Microbiology and Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands; (J.v.D.); (M.A.)
| | - Mark Arentshorst
- Department Molecular Microbiology and Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands; (J.v.D.); (M.A.)
| | - Arthur F. J. Ram
- TIFN, Agro Business Park 82, 6708 PW Wageningen, The Netherlands;
- Department Molecular Microbiology and Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands; (J.v.D.); (M.A.)
- Correspondence:
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9
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Rahman S, van Rhijn N, Papastamoulis P, Thomson DD, Carter Z, Fortune-Grant R, Rattray M, Bromley MJ, Bignell E. Distinct Cohorts of Aspergillus fumigatus Transcription Factors Are Required for Epithelial Damage Occurring via Contact- or Soluble Effector-Mediated Mechanisms. Front Cell Infect Microbiol 2022; 12:907519. [PMID: 35982778 PMCID: PMC9379863 DOI: 10.3389/fcimb.2022.907519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 05/18/2022] [Indexed: 11/16/2022] Open
Abstract
Damage to the lung epithelium is a unifying feature of disease caused by the saprophytic fungus Aspergillus fumigatus. However, the mechanistic basis and the regulatory control of such damage is poorly characterized. Previous studies have identified A. fumigatus mediated pathogenesis as occurring at early (≤ 16 hours) or late (>16 hours) phases of the fungal interaction with epithelial cells, and respectively involve direct contact with the host cell or the action of soluble factors produced by mature fungal hyphae. Both early and late phases of epithelial damage have been shown to be subject to genetic regulation by the pH-responsive transcription factor PacC. This study sought to determine whether other transcriptional regulators play a role in modulating epithelial damage. In particular, whether the early and late phases of epithelial damage are governed by same or distinct regulators. Furthermore, whether processes such as spore uptake and hyphal adhesion, that have previously been documented to promote epithelial damage, are governed by the same cohorts of epithelial regulators. Using 479 strains from the recently constructed library of A. fumigatus transcription factor null mutants, two high-throughput screens assessing epithelial cell detachment and epithelial cell lysis were conducted. A total of 17 transcription factor mutants were found to exhibit reproducible deficits in epithelial damage causation. Of these, 10 mutants were defective in causing early phase damage via epithelial detachment and 8 mutants were defective in causing late phase damage via epithelial lysis. Remarkably only one transcription factor, PacC, was required for causation of both phases of epithelial damage. The 17 mutants exhibited varied and often unique phenotypic profiles with respect to fitness, epithelial adhesion, cell wall defects, and rates of spore uptake by epithelial cells. Strikingly, 9 out of 10 mutants deficient in causing early phase damage also exhibited reduced rates of hyphal extension, and culture supernatants of 7 out of 8 mutants deficient in late phase damage were significantly less cytotoxic. Our study delivers the first high-level overview of A. fumigatus regulatory genes governing lung epithelial damage, suggesting highly coordinated genetic orchestration of host-damaging activities that govern epithelial damage in both space and time.
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Affiliation(s)
- Sayema Rahman
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Norman van Rhijn
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | | | - Darren D Thomson
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.,MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Zorana Carter
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Rachael Fortune-Grant
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Magnus Rattray
- Division of Informatics, School of Heath Sciences, University of Manchester, Manchester, United Kingdom
| | - Michael John Bromley
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Elaine Bignell
- Manchester Fungal Infection Group, Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.,MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
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10
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The Heterotrimeric Transcription Factor CCAAT-Binding Complex and Ca 2+-CrzA Signaling Reversely Regulate the Transition between Fungal Hyphal Growth and Asexual Reproduction. mBio 2021; 12:e0300721. [PMID: 34781745 PMCID: PMC8593669 DOI: 10.1128/mbio.03007-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The life cycle of filamentous fungi generally comprises hyphal growth and asexual reproduction. Both growth and propagation processes are critical for invasion growth, spore dissemination, and virulence in fungal pathogens and for the production of secondary metabolites or for biomass accumulation in industrial filamentous fungi. The CCAAT-binding complex (CBC) is a heterotrimeric transcription factor comprising three subunits, HapB, HapC, and HapE, and is highly conserved in fungi. Previous studies revealed that CBC regulates sterol metabolism by repressing several genes in the ergosterol biosynthetic pathway in the human fungal pathogen Aspergillus fumigatus. In the present study, we found dysfunction of CBC caused the abnormal asexual reproduction (conidiation) in submerged liquid culture. CBC suppresses the activation of the brlA gene in the central regulatory pathway for conidiation combined with its upstream regulators fluG, flbD, and flbC by binding to the 5'-CCAAT-3' motif within conidiation gene promoters, and lack of CBC member HapB results in the upregulation of these genes. Furthermore, when the expression of brlA or flbC is repressed, the submerged conidiation does not happen in the hapB mutant. Interestingly, deletion of HapB leads to enhanced transient cytosolic Ca2+ levels and activates conidiation-positive inducer Ca2+-CrzA modules to enhance submerged conidiation, demonstrating that CrzA works with CBC as a reverse regulator of fungal conidiation. To the best of our knowledge, the finding of this study is the first report for the molecular switch mechanism between vegetative hyphal growth and asexual development regulated by CBC, in concert with Ca2+-CrzA signaling in A. fumigatus. IMPORTANCE A precisely timed switch between vegetative hyphal growth and asexual development is a crucial process for the filamentous fungal long-term survival, dissemination, biomass production, and virulence. However, under the submerged culture condition, filamentous fungi would undergo constant vegetative growth whereas asexual conidiation rarely occurs. Knowledge about possible regulators is scarce, and how they could inhibit conidiation in liquid culture is poorly understood. Here, we demonstrated that the transcription factor heterotrimeric CBC dominantly maintains vegetative growth in liquid-submerged cultures by directly suppressing the conidiation-inductive signal. In contrast, calcium and the transcription factor CrzA, are positive inducers of conidiation. Our new insights into the CBC and Ca2+-CrzA regulatory system for transition control in the submerged conidiation of A. fumigatus may have broad repercussions for all filamentous fungi. Moreover, our elucidation of the molecular mechanism for submerged conidiation may support new strategies to precisely control vegetative growth and asexual conidiation in aspergilli used in industry.
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