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Liu F, Zeng M, Zhou X, Huang F, Song Z. Aspergillus fumigatus escape mechanisms from its harsh survival environments. Appl Microbiol Biotechnol 2024; 108:53. [PMID: 38175242 DOI: 10.1007/s00253-023-12952-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/09/2023] [Accepted: 10/19/2023] [Indexed: 01/05/2024]
Abstract
Aspergillus fumigatus is a ubiquitous pathogenic mold and causes several diseases, including mycotoxicosis, allergic reactions, and systemic diseases (invasive aspergillosis), with high mortality rates. In its ecological niche, the fungus has evolved and mastered many reply strategies to resist and survive against negative threats, including harsh environmental stress and deficiency of essential nutrients from natural environments, immunity responses and drug treatments in host, and competition from symbiotic microorganisms. Hence, treating A. fumigatus infection is a growing challenge. In this review, we summarized A. fumigatus reply strategies and escape mechanisms and clarified the main competitive or symbiotic relationships between A. fumigatus, viruses, bacteria, or fungi in host microecology. Additionally, we discussed the contemporary drug repertoire used to treat A. fumigatus and the latest evidence of potential resistance mechanisms. This review provides valuable knowledge which will stimulate further investigations and clinical applications for treating and preventing A. fumigatus infections. KEY POINTS: • Harsh living environment was a great challenge for A. fumigatus survival. • A. fumigatus has evolved multiple strategies to escape host immune responses. • A. fumigatus withstands antifungal drugs via intrinsic escape mechanisms.
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Affiliation(s)
- Fangyan Liu
- School of Basic Medical Sciences, Southwest Medical University, Luzhou, 646000, People's Republic of China
| | - Meng Zeng
- School of Basic Medical Sciences, Southwest Medical University, Luzhou, 646000, People's Republic of China
- Department of Clinical Laboratory, Yongchuan Hospital of Chongqing Medical University, Chongqing, 402160, People's Republic of China
| | - Xue Zhou
- School of Basic Medical Sciences, Southwest Medical University, Luzhou, 646000, People's Republic of China
| | - Fujiao Huang
- School of Basic Medical Sciences, Southwest Medical University, Luzhou, 646000, People's Republic of China
| | - Zhangyong Song
- School of Basic Medical Sciences, Southwest Medical University, Luzhou, 646000, People's Republic of China.
- Molecular Biotechnology Platform, Public Center of Experimental Technology, Southwest Medical University, Luzhou, 646000, People's Republic of China.
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Wu D, Guan YX, Li CH, Zheng Q, Yin ZJ, Wang H, Liu NN. "Nutrient-fungi-host" tripartite interaction in cancer progression. IMETA 2024; 3:e170. [PMID: 38882486 PMCID: PMC11170973 DOI: 10.1002/imt2.170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 01/04/2024] [Accepted: 01/05/2024] [Indexed: 06/18/2024]
Abstract
The human microbiome exhibits a profound connection with the cancer development, progression, and therapeutic response, with particular emphasis on its components of the mycobiome, which are still in the early stages of research. In this review, we comprehensively summarize cancer-related symbiotic and pathogenic fungal genera. The intricate mechanisms through which fungi impact cancer as an integral member of both gut and tissue-resident microbiomes are further discussed. In addition, we shed light on the pivotal physiological roles of various nutrients, including cholesterol, carbohydrates, proteins and minerals, in facilitating the growth, reproduction, and invasive pathogenesis of the fungi. While our exploration of the interplay between nutrients and cancer, mediated by the mycobiome, is ongoing, the current findings have yet to yield conclusive results. Thus, delving into the relationship between nutrients and fungal pathogenesis in cancer development and progression would provide valuable insights into anticancer therapy and foster precision nutrition and individualized treatments that target fungi from bench to bedside.
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Affiliation(s)
- Di Wu
- State Key Laboratory of Systems Medicine for Cancer, Center for Single-Cell Omics, School of Public Health Shanghai Jiao Tong University School of Medicine Shanghai China
| | - Yun-Xuan Guan
- State Key Laboratory of Systems Medicine for Cancer, Center for Single-Cell Omics, School of Public Health Shanghai Jiao Tong University School of Medicine Shanghai China
| | - Chen-Hao Li
- Institute of Computing Technology Chinese Academy of Sciences Beijing China
| | - Quan Zheng
- State Key Laboratory of Systems Medicine for Cancer, Center for Single-Cell Omics, School of Public Health Shanghai Jiao Tong University School of Medicine Shanghai China
| | - Zuo-Jing Yin
- State Key Laboratory of Systems Medicine for Cancer, Center for Single-Cell Omics, School of Public Health Shanghai Jiao Tong University School of Medicine Shanghai China
| | - Hui Wang
- State Key Laboratory of Systems Medicine for Cancer, Center for Single-Cell Omics, School of Public Health Shanghai Jiao Tong University School of Medicine Shanghai China
| | - Ning-Ning Liu
- State Key Laboratory of Systems Medicine for Cancer, Center for Single-Cell Omics, School of Public Health Shanghai Jiao Tong University School of Medicine Shanghai China
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Dabholkar A, Pandit S, Devkota R, Dhingra S, Lorber S, Puel O, Calvo AM. Role of the osaA Gene in Aspergillus fumigatus Development, Secondary Metabolism and Virulence. J Fungi (Basel) 2024; 10:103. [PMID: 38392775 PMCID: PMC10890407 DOI: 10.3390/jof10020103] [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: 12/20/2023] [Revised: 01/17/2024] [Accepted: 01/22/2024] [Indexed: 02/24/2024] Open
Abstract
Aspergillus fumigatus is the leading cause of aspergillosis, associated with high mortality rates, particularly in immunocompromised individuals. In search of novel genetic targets against aspergillosis, we studied the WOPR transcription factor OsaA. The deletion of the osaA gene resulted in colony growth reduction. Conidiation is also influenced by osaA; both osaA deletion and overexpression resulted in a decrease in spore production. Wild-type expression levels of osaA are necessary for the expression of the conidiation regulatory genes brlA, abaA, and wetA. In addition, osaA is necessary for normal cell wall integrity. Furthermore, the deletion of osaA resulted in a reduction in the ability of A. fumigatus to adhere to surfaces, decreased thermotolerance, as well as increased sensitivity to oxidative stress. Metabolomics analysis indicated that osaA deletion or overexpression led to alterations in the production of multiple secondary metabolites, including gliotoxin. This was accompanied by changes in the expression of genes in the corresponding secondary metabolite gene clusters. These effects could be, at least in part, due to the observed reduction in the expression levels of the veA and laeA global regulators when the osaA locus was altered. Importantly, our study shows that osaA is indispensable for virulence in both neutropenic and corticosteroid-immunosuppressed mouse models.
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Affiliation(s)
- Apoorva Dabholkar
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA
| | - Sandesh Pandit
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA
| | - Ritu Devkota
- Department of Biological Sciences and Eukaryotic Pathogen Innovation Center, Clemson University, Clemson, SC 29634, USA
| | - Sourabh Dhingra
- Department of Biological Sciences and Eukaryotic Pathogen Innovation Center, Clemson University, Clemson, SC 29634, USA
| | - Sophie Lorber
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, 31027 Toulouse, France
| | - Olivier Puel
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, 31027 Toulouse, France
| | - Ana M Calvo
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA
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Earle K, Valero C, Conn DP, Vere G, Cook PC, Bromley MJ, Bowyer P, Gago S. Pathogenicity and virulence of Aspergillus fumigatus. Virulence 2023; 14:2172264. [PMID: 36752587 PMCID: PMC10732619 DOI: 10.1080/21505594.2023.2172264] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 12/16/2022] [Indexed: 02/09/2023] Open
Abstract
Pulmonary infections caused by the mould pathogen Aspergillus fumigatus are a major cause of morbidity and mortality globally. Compromised lung defences arising from immunosuppression, chronic respiratory conditions or more recently, concomitant viral or bacterial pulmonary infections are recognised risks factors for the development of pulmonary aspergillosis. In this review, we will summarise our current knowledge of the mechanistic basis of pulmonary aspergillosis with a focus on emerging at-risk populations.
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Affiliation(s)
- Kayleigh Earle
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Clara Valero
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Daniel P. Conn
- MRC Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - George Vere
- MRC Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Peter C. Cook
- MRC Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Michael J. Bromley
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Paul Bowyer
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Sara Gago
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
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Lian L, Qiao J, Guo X, Xing Z, Ren A, Zhao M, Zhu J. The transcription factor GCN4 contributes to maintaining intracellular amino acid contents under nitrogen-limiting conditions in the mushroom Ganoderma lucidum. Microb Cell Fact 2023; 22:205. [PMID: 37817159 PMCID: PMC10563202 DOI: 10.1186/s12934-023-02213-z] [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: 06/29/2023] [Accepted: 09/26/2023] [Indexed: 10/12/2023] Open
Abstract
BACKGROUND Edible mushrooms are delicious in flavour and rich in high-quality protein and amino acids required by humans. A transcription factor, general control nonderepressible 4 (GCN4), can regulate the expression of genes involved in amino acid metabolism in yeast and mammals. A previous study revealed that GCN4 plays a pivotal role in nitrogen utilization and growth in Ganoderma lucidum. However, its regulation is nearly unknown in mushrooms. RESULTS In this study, we found that the amino acid contents reached 120.51 mg per gram of mycelia in the WT strain under 60 mM asparagine (Asn) conditions, but decreased by 62.96% under 3 mM Asn conditions. Second, silencing of gcn4 resulted in a 54.2% decrease in amino acid contents under 60 mM Asn, especially for the essential and monosodium glutamate-like flavour amino acids. However, these effects were more pronounced under 3 mM Asn. Third, silencing of gcn4 markedly inhibited the expression of amino acid biosynthesis and transport genes. In addition, GCN4 enhanced the tricarboxylic acid cycle (TCA) and glycolytic pathway and inhibited the activity of target of rapamycin complex 1 (TORC1), thus being beneficial for maintaining amino acid homeostasis. CONCLUSION This study confirmed that GCN4 contributes to maintaining the amino acid contents in mushrooms under low concentrations of nitrogen. In conclusion, our study provides a research basis for GCN4 to regulate amino acid synthesis and improve the nutrient contents of edible mushrooms.
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Affiliation(s)
- Lingdan Lian
- Key Laboratory of Agricultural Environmental Microbiology, Microbiology Department, College of Life Sciences, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Jiangsu, Nanjing, 210095, PR China
- Department of Bioengineering, College of Food Science, South China Agricultural University, Guangzhou, 510642, PR China
| | - Jinjin Qiao
- Key Laboratory of Agricultural Environmental Microbiology, Microbiology Department, College of Life Sciences, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Jiangsu, Nanjing, 210095, PR China
| | - Xiaoyu Guo
- Key Laboratory of Agricultural Environmental Microbiology, Microbiology Department, College of Life Sciences, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Jiangsu, Nanjing, 210095, PR China
| | - Zhenzhen Xing
- Key Laboratory of Agricultural Environmental Microbiology, Microbiology Department, College of Life Sciences, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Jiangsu, Nanjing, 210095, PR China
| | - Ang Ren
- Key Laboratory of Agricultural Environmental Microbiology, Microbiology Department, College of Life Sciences, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Jiangsu, Nanjing, 210095, PR China
| | - Mingwen Zhao
- Key Laboratory of Agricultural Environmental Microbiology, Microbiology Department, College of Life Sciences, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Jiangsu, Nanjing, 210095, PR China
| | - Jing Zhu
- Key Laboratory of Agricultural Environmental Microbiology, Microbiology Department, College of Life Sciences, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Jiangsu, Nanjing, 210095, PR China.
- College of Life Sciences, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu, 210095, PR China.
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Steyer JT, Todd RB. Branched-chain amino acid biosynthesis in fungi. Essays Biochem 2023; 67:865-876. [PMID: 37455545 DOI: 10.1042/ebc20230003] [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: 05/03/2023] [Revised: 06/27/2023] [Accepted: 06/29/2023] [Indexed: 07/18/2023]
Abstract
Branched-chain amino acids (BCAAs)-isoleucine, leucine, and valine-are synthesized by fungi. These amino acids are important components of proteins and secondary metabolites. The biochemical pathway for BCAA biosynthesis is well-characterized in the yeast Saccharomyces cerevisiae. The biosynthesis of these three amino acids is interconnected. Different precursors are metabolized in multiple steps through shared enzymes to produce isoleucine and valine, and the valine biosynthesis pathway branches before the penultimate step to a series of leucine biosynthesis-specific steps to produce leucine. Recent efforts have made advances toward characterization of the BCAA biosynthesis pathway in several fungi, revealing diversity in gene duplication and functional divergence in the genes for these enzymatic steps in different fungi. The BCAA biosynthesis pathway is regulated by the transcription factor LEU3 in S. cerevisiae, and LeuB in Aspergillus nidulans and Aspergillus fumigatus, and the activity of these transcription factors is modulated by the leucine biosynthesis pathway intermediate α-isopropylmalate. Herein, we discuss recent advances in our understanding of the BCAA pathway and its regulation, focusing on filamentous ascomycete fungi and comparison with the well-established process in yeast.
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Affiliation(s)
- Joel T Steyer
- Department of Plant Pathology, Kansas State University, Manhattan KS, 66506, U.S.A
| | - Richard B Todd
- Department of Plant Pathology, Kansas State University, Manhattan KS, 66506, U.S.A
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Li F, Gao Y, Cheng W, Su X, Yang R. Gut fungal mycobiome: A significant factor of tumor occurrence and development. Cancer Lett 2023; 569:216302. [PMID: 37451425 DOI: 10.1016/j.canlet.2023.216302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 06/28/2023] [Accepted: 07/01/2023] [Indexed: 07/18/2023]
Abstract
A variety of bacteria, viruses, fungi, protists, archaea and protozoa coexists within the mammalian gastrointestinal (GI) tract such as that fungi are detectable in all intestinal and colon segments in almost all healthy adults. Although fungi can cause infectious diseases, they are also related to gut and systemic homeostasis. Importantly, through transformation of different forms such as from yeast to hyphae, interaction among gut microbiota such as fungal and bacterial interaction, host factors such as immune and host derived factors, and fungus genetic and epigenetic factors, fungi can be transformed from commensal into pathogenic lifestyles. Recent studies have shown that fungi play a significant role in the occurrence and development of tumors such as colorectal cancer. Indeed, evidences have shown that multiple species of different fungi exist in different tumors. Studies have also demonstrated that fungi are related to the occurrence and development of tumors, and also survival of patients. Here we summarize recent advances in the transformation of fungi from commensal into pathogenic lifestyles, and the effects of gut pathogenic fungi on the occurrence and development of tumors such as colorectal and pancreatic cancers.
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Affiliation(s)
- Fan Li
- Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China; Department of Immunology, Nankai University School of Medicine, Nankai University, Tianjin, 300071, China; State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071, China
| | - Yunhuan Gao
- Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China; Department of Immunology, Nankai University School of Medicine, Nankai University, Tianjin, 300071, China; State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071, China
| | - Wenyue Cheng
- Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China; Department of Immunology, Nankai University School of Medicine, Nankai University, Tianjin, 300071, China; State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071, China
| | - Xiaomin Su
- Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China; Department of Immunology, Nankai University School of Medicine, Nankai University, Tianjin, 300071, China; State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071, China
| | - Rongcun Yang
- Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China; Department of Immunology, Nankai University School of Medicine, Nankai University, Tianjin, 300071, China; State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071, China.
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8
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Proctor DM, Drummond RA, Lionakis MS, Segre JA. One population, multiple lifestyles: Commensalism and pathogenesis in the human mycobiome. Cell Host Microbe 2023; 31:539-553. [PMID: 37054674 PMCID: PMC10155287 DOI: 10.1016/j.chom.2023.02.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/12/2023] [Accepted: 02/23/2023] [Indexed: 04/15/2023]
Abstract
Candida auris and Candida albicans can result in invasive fungal diseases. And yet, these species can stably and asymptomatically colonize human skin and gastrointestinal tracts. To consider these disparate microbial lifestyles, we first review factors shown to influence the underlying microbiome. Structured by the damage response framework, we then consider the molecular mechanisms deployed by C. albicans to switch between commensal and pathogenic lifestyles. Next, we explore this framework with C. auris to highlight how host physiology, immunity, and/or antibiotic receipt are associated with progression from colonization to infection. While treatment with antibiotics increases the risk that an individual will succumb to invasive candidiasis, the underlying mechanisms remain unclear. Here, we describe several hypotheses that may explain this phenomenon. We conclude by highlighting future directions integrating genomics with immunology to advance our understanding of invasive candidiasis and human fungal disease.
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Affiliation(s)
- Diana M Proctor
- Microbial Genomics Section, Translational and Functional Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Rebecca A Drummond
- Institute of Immunology & Immunotherapy, Institute of Microbiology & Infection, University of Birmingham, Birmingham B15 2TT, UK
| | - Michail S Lionakis
- Fungal Pathogenesis Section, Laboratory of Clinical Immunology and Microbiology (LCIM), National Institute of Allergy & Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Julia A Segre
- Microbial Genomics Section, Translational and Functional Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Brown AJP. Fungal resilience and host-pathogen interactions: Future perspectives and opportunities. Parasite Immunol 2023; 45:e12946. [PMID: 35962618 PMCID: PMC10078341 DOI: 10.1111/pim.12946] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 08/08/2022] [Accepted: 08/10/2022] [Indexed: 01/31/2023]
Abstract
We are constantly exposed to the threat of fungal infection. The outcome-clearance, commensalism or infection-depends largely on the ability of our innate immune defences to clear infecting fungal cells versus the success of the fungus in mounting compensatory adaptive responses. As each seeks to gain advantage during these skirmishes, the interactions between host and fungal pathogen are complex and dynamic. Nevertheless, simply compromising the physiological robustness of fungal pathogens reduces their ability to evade antifungal immunity, their virulence, and their tolerance against antifungal therapy. In this article I argue that this physiological robustness is based on a 'Resilience Network' which mechanistically links and controls fungal growth, metabolism, stress resistance and drug tolerance. The elasticity of this network probably underlies the phenotypic variability of fungal isolates and the heterogeneity of individual cells within clonal populations. Consequently, I suggest that the definition of the fungal Resilience Network represents an important goal for the future which offers the clear potential to reveal drug targets that compromise drug tolerance and synergise with current antifungal therapies.
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Affiliation(s)
- Alistair J P Brown
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, UK
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10
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Aspergillus fumigatus Elongator complex subunit 3 affects hyphal growth, adhesion and virulence through wobble uridine tRNA modification. PLoS Pathog 2022; 18:e1010976. [DOI: 10.1371/journal.ppat.1010976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 11/28/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022] Open
Abstract
The eukaryotic multisubunit Elongator complex has been shown to perform multiple functions in transcriptional elongation, histone acetylation and tRNA modification. However, the Elongator complex plays different roles in different organisms, and the underlying mechanisms remain unexplored. Moreover, the biological functions of the Elongator complex in human fungal pathogens remain unknown. In this study, we verified that the Elongator complex of the opportunistic fungal pathogen Aspergillus fumigatus consists of six subunits (Elp1-6), and the loss of any subunit results in similarly defective colony phenotypes with impaired hyphal growth and reduced conidiation. The catalytic subunit-Elp3 of the Elongator complex includes a S-adenosyl methionine binding (rSAM) domain and a lysine acetyltransferase (KAT) domain, and it plays key roles in the hyphal growth, biofilm-associated exopolysaccharide galactosaminogalactan (GAG) production, adhesion and virulence of A. fumigatus; however, Elp3 does not affect H3K14 acetylation levels in vivo. LC–MS/MS chromatograms revealed that loss of Elp3 abolished the 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U) modification of tRNA wobble uridine (U34), and the overexpression of tRNAGlnUUG and tRNAGluUUC, which normally harbor mcm5s2U modifications, mainly rescues the defects of the Δelp3 mutant, suggesting that tRNA modification rather than lysine acetyltransferase is responsible for the primary function of Elp3 in A. fumigatus. Strikingly, global proteomic comparison analyses showed significantly upregulated expression of genes related to amino acid metabolism in the Δelp3 mutant strain compared to the wild-type strain. Western blotting showed that deletion of elp3 resulted in overexpression of the amino acid starvation-responsive transcription factor CpcA, and deletion of CpcA markedly reversed the defective phenotypes of the Δelp3 mutant, including attenuated virulence. Therefore, the findings of this study demonstrate that A. fumigatus Elp3 functions as a tRNA-modifying enzyme in the regulation of growth, GAG production, adhesion and virulence by maintaining intracellular amino acid homeostasis. More broadly, our study highlights the importance of U34 tRNA modification in regulating cellular metabolic states and virulence traits of fungal pathogens.
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11
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Systematic Characterization of bZIP Transcription Factors Required for Development and Aflatoxin Generation by High-Throughput Gene Knockout in Aspergillus flavus. J Fungi (Basel) 2022; 8:jof8040356. [PMID: 35448587 PMCID: PMC9031554 DOI: 10.3390/jof8040356] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/23/2022] [Accepted: 03/23/2022] [Indexed: 12/31/2022] Open
Abstract
The basic leucine zipper (bZIP) is an important transcription factor required for fungal development, nutrient utilization, biosynthesis of secondary metabolites, and defense against various stresses. Aspergillus flavus is a major producer of aflatoxin and an opportunistic fungus on a wide range of hosts. However, little is known about the role of most bZIP genes in A. flavus. In this study, we developed a high-throughput gene knockout method based on an Agrobacterium-mediated transformation system. Gene knockout construction by yeast recombinational cloning and screening of the null mutants by double fluorescence provides an efficient way to construct gene-deleted mutants for this multinucleate fungus. We deleted 15 bZIP genes in A. flavus. Twelve of these genes were identified and characterized in this strain for the first time. The phenotypic analysis of these mutants showed that the 15 bZIP genes play a diverse role in mycelial growth (eight genes), conidiation (13 genes), aflatoxin biosynthesis (10 genes), oxidative stress response (11 genes), cell wall stress (five genes), osmotic stress (three genes), acid and alkali stress (four genes), and virulence to kernels (nine genes). Impressively, all 15 genes were involved in the development of sclerotia, and the respective deletion mutants of five of them did not produce sclerotia. Moreover, MetR was involved in this biological process. In addition, HapX and MetR play important roles in the adaptation to excessive iron and sulfur metabolism, respectively. These studies provide comprehensive insights into the role of bZIP transcription factors in this aflatoxigenic fungus of global significance.
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12
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Shao S, Li B, Sun Q, Guo P, Du Y, Huang J. Acetolactate synthases regulatory subunit and catalytic subunit genes VdILVs are involved in BCAA biosynthesis, microscletotial and conidial formation and virulence in Verticillium dahliae. Fungal Genet Biol 2022; 159:103667. [PMID: 35041986 DOI: 10.1016/j.fgb.2022.103667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 01/02/2022] [Accepted: 01/11/2022] [Indexed: 11/26/2022]
Abstract
Acetolactate synthase (AHAS) catalyses the first common step in the biosynthesis pathways of three branched-chain amino acids (BCAAs) of valine, isoleucine and leucine. Here, we characterized one regulatory subunit (VdILV6) and three catalytic subunits (VdILV2A, VdILV2B and VdILV2C) of AHAS from the important cotton Verticillium wilt fungus Verticillium dahliae. Phenotypic analysis showed that VdILV6 knockout mutants were auxotrophic for valine and isoleucine and were defective in conidial morphogenesis, hypha penetration and virulence to cotton, and lost ability of microscletotial formation. The growth of single catalytic subunit gene knockout mutants were significantly inhibited by leucine at higher concentration and single catalytic subunit gene knockout mutants showed significantly reduced virulence to cotton. VdILV2B knockout also led to obviously reduced microscletotial formation and conidial production, VdILV2C knockout led to reduced conidial production. Further studies suggested that both feedback inhibition by leucine and the inhibition by AHAS inhibiting herbicides of tribenuron and bispyribac resulted in significantly down-regulated expression of the four subunit VdILVs genes (VdILV2A, VdILV2B, VdILV2C and VdILV6). Any single catalytic subunit gene knockout led to reduced expression of the other three subunit genes, whereas VdILV6 knckout induced increased expression of the three catalytic subunit genes. VdILV2B, VdILV2C and VdILV6 knockout resulted in increased expression of VdCPC1 regulator gene of the cross-pathway control of amino acid biosynthesis. Taken together, these results indicate multiple roles of four VdILVs genes in the biosynthesis of BCAAs, virulence, fungal growth and development in the filamentous fungi V. dahliae.
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Affiliation(s)
- ShengNan Shao
- College of Agriculture / Key Laboratory of Oasis Agricultural Pest Management and Plant Protection Resources Utilization, Xinjiang Uygur Autonomous Region, Shihezi University, Shihezi 832003, Xinjiang
| | - Biao Li
- College of Agriculture / Key Laboratory of Oasis Agricultural Pest Management and Plant Protection Resources Utilization, Xinjiang Uygur Autonomous Region, Shihezi University, Shihezi 832003, Xinjiang
| | - Qi Sun
- College of Agriculture / Key Laboratory of Oasis Agricultural Pest Management and Plant Protection Resources Utilization, Xinjiang Uygur Autonomous Region, Shihezi University, Shihezi 832003, Xinjiang
| | - PeiRu Guo
- College of Agriculture / Key Laboratory of Oasis Agricultural Pest Management and Plant Protection Resources Utilization, Xinjiang Uygur Autonomous Region, Shihezi University, Shihezi 832003, Xinjiang
| | - YeJuan Du
- College of Agriculture / Key Laboratory of Oasis Agricultural Pest Management and Plant Protection Resources Utilization, Xinjiang Uygur Autonomous Region, Shihezi University, Shihezi 832003, Xinjiang.
| | - JiaFeng Huang
- College of Agriculture / Key Laboratory of Oasis Agricultural Pest Management and Plant Protection Resources Utilization, Xinjiang Uygur Autonomous Region, Shihezi University, Shihezi 832003, Xinjiang.
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13
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Olivares-Yañez C, Sánchez E, Pérez-Lara G, Seguel A, Camejo PY, Larrondo LF, Vidal EA, Canessa P. A comprehensive transcription factor and DNA-binding motif resource for the construction of gene regulatory networks in Botrytis cinerea and Trichoderma atroviride. Comput Struct Biotechnol J 2021; 19:6212-6228. [PMID: 34900134 PMCID: PMC8637145 DOI: 10.1016/j.csbj.2021.11.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/11/2021] [Accepted: 11/11/2021] [Indexed: 11/25/2022] Open
Abstract
Botrytis cinerea and Trichoderma atroviride are two relevant fungi in agricultural systems. To gain insights into these organisms' transcriptional gene regulatory networks (GRNs), we generated a manually curated transcription factor (TF) dataset for each of them, followed by a GRN inference utilizing available sequence motifs describing DNA-binding specificity and global gene expression data. As a proof of concept of the usefulness of this resource to pinpoint key transcriptional regulators, we employed publicly available transcriptomics data and a newly generated dual RNA-seq dataset to build context-specific Botrytis and Trichoderma GRNs under two different biological paradigms: exposure to continuous light and Botrytis-Trichoderma confrontation assays. Network analysis of fungal responses to constant light revealed striking differences in the transcriptional landscape of both fungi. On the other hand, we found that the confrontation of both microorganisms elicited a distinct set of differentially expressed genes with changes in T. atroviride exceeding those in B. cinerea. Using our regulatory network data, we were able to determine, in both fungi, central TFs involved in this interaction response, including TFs controlling a large set of extracellular peptidases in the biocontrol agent T. atroviride. In summary, our work provides a comprehensive catalog of transcription factors and regulatory interactions for both organisms. This catalog can now serve as a basis for generating novel hypotheses on transcriptional regulatory circuits in different experimental contexts.
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Affiliation(s)
- Consuelo Olivares-Yañez
- ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Avda. Libertador Bernardo O'Higgins 340, Santiago, Chile.,Centro de Biotecnologia Vegetal, Universidad Andres Bello, Republica 330, Santiago, Chile
| | - Evelyn Sánchez
- ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Avda. Libertador Bernardo O'Higgins 340, Santiago, Chile.,Centro de Genomica y Bioinformatica, Facultad de Ciencias, Universidad Mayor, Camino la Pirámide 5750, Huechuraba, Santiago, Chile
| | - Gabriel Pérez-Lara
- ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Avda. Libertador Bernardo O'Higgins 340, Santiago, Chile.,Centro de Biotecnologia Vegetal, Universidad Andres Bello, Republica 330, Santiago, Chile
| | - Aldo Seguel
- ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Avda. Libertador Bernardo O'Higgins 340, Santiago, Chile.,Departamento de Genetica Molecular y Microbiologia, Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Avda. Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Pamela Y Camejo
- ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Avda. Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Luis F Larrondo
- ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Avda. Libertador Bernardo O'Higgins 340, Santiago, Chile.,Departamento de Genetica Molecular y Microbiologia, Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Avda. Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Elena A Vidal
- ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Avda. Libertador Bernardo O'Higgins 340, Santiago, Chile.,Centro de Genomica y Bioinformatica, Facultad de Ciencias, Universidad Mayor, Camino la Pirámide 5750, Huechuraba, Santiago, Chile.,Escuela de Biotecnologia, Facultad de Ciencias, Universidad Mayor, Camino la Pirámide 5750, Huechuraba, Santiago, Chile
| | - Paulo Canessa
- ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Avda. Libertador Bernardo O'Higgins 340, Santiago, Chile.,Centro de Biotecnologia Vegetal, Universidad Andres Bello, Republica 330, Santiago, Chile
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14
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Rana A, Gupta N, Thakur A. Post-transcriptional and translational control of the morphology and virulence in human fungal pathogens. Mol Aspects Med 2021; 81:101017. [PMID: 34497025 DOI: 10.1016/j.mam.2021.101017] [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: 02/11/2021] [Revised: 08/13/2021] [Accepted: 08/20/2021] [Indexed: 11/17/2022]
Abstract
Host-pathogen interactions at the molecular level are the key to fungal pathogenesis. Fungal pathogens utilize several mechanisms such as adhesion, invasion, phenotype switching and metabolic adaptations, to survive in the host environment and respond. Post-transcriptional and translational regulations have emerged as key regulatory mechanisms ensuring the virulence and survival of fungal pathogens. Through these regulations, fungal pathogens effectively alter their protein pool, respond to various stress, and undergo morphogenesis, leading to efficient and comprehensive changes in fungal physiology. The regulation of virulence through post-transcriptional and translational regulatory mechanisms is mediated through mRNA elements (cis factors) or effector molecules (trans factors). The untranslated regions upstream and downstream of the mRNA, as well as various RNA-binding proteins involved in translation initiation or circularization of the mRNA, play pivotal roles in the regulation of morphology and virulence by influencing protein synthesis, protein isoforms, and mRNA stability. Therefore, post-transcriptional and translational mechanisms regulating the morphology, virulence and drug-resistance processes in fungal pathogens can be the target for new therapeutics. With improved "omics" technologies, these regulatory mechanisms are increasingly coming to the forefront of basic biology and drug discovery. This review aims to discuss various modes of post-transcriptional and translation regulations, and how these mechanisms exert influence in the virulence and morphogenesis of fungal pathogens.
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Affiliation(s)
- Aishwarya Rana
- Regional Centre for Biotechnology, 3rd Milestone Gurgaon-Faridabad Expressway, Faridabad 121001, India
| | - Nidhi Gupta
- Regional Centre for Biotechnology, 3rd Milestone Gurgaon-Faridabad Expressway, Faridabad 121001, India
| | - Anil Thakur
- Regional Centre for Biotechnology, 3rd Milestone Gurgaon-Faridabad Expressway, Faridabad 121001, India.
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15
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Nitrogen, Iron and Zinc Acquisition: Key Nutrients to Aspergillus fumigatus Virulence. J Fungi (Basel) 2021; 7:jof7070518. [PMID: 34203370 PMCID: PMC8303583 DOI: 10.3390/jof7070518] [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] [Received: 06/01/2021] [Revised: 06/24/2021] [Accepted: 06/24/2021] [Indexed: 12/31/2022] Open
Abstract
Aspergillus fumigatus is a ubiquitous soil decomposer and an opportunistic pathogen that is characterized by its large metabolic machinery for acquiring nutrients from media. Lately, an ever-increasing number of genes involved in fungal nutrition has been associated with its virulence. Of these, nitrogen, iron, and zinc metabolism-related genes are particularly noteworthy, since 78% of them have a direct implication in virulence. In this review, we describe the sensing, uptake and regulation process of the acquisition of these nutrients, the connections between pathways and the virulence-implicated genes. Nevertheless, only 40% of the genes mentioned in this review have been assayed for roles in virulence, leaving a wide field of knowledge that remains uncertain and might offer new therapeutic and diagnostic targets.
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16
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Zelante T, Choera T, Beauvais A, Fallarino F, Paolicelli G, Pieraccini G, Pieroni M, Galosi C, Beato C, De Luca A, Boscaro F, Romoli R, Liu X, Warris A, Verweij PE, Ballard E, Borghi M, Pariano M, Costantino G, Calvitti M, Vacca C, Oikonomou V, Gargaro M, Wong AYW, Boon L, den Hartog M, Spáčil Z, Puccetti P, Latgè JP, Keller NP, Romani L. Aspergillus fumigatus tryptophan metabolic route differently affects host immunity. Cell Rep 2021; 34:108673. [PMID: 33503414 PMCID: PMC7844877 DOI: 10.1016/j.celrep.2020.108673] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/20/2020] [Accepted: 12/30/2020] [Indexed: 12/28/2022] Open
Abstract
Indoleamine 2,3-dioxygenases (IDOs) degrade l-tryptophan to kynurenines and drive the de novo synthesis of nicotinamide adenine dinucleotide. Unsurprisingly, various invertebrates, vertebrates, and even fungi produce IDO. In mammals, IDO1 also serves as a homeostatic regulator, modulating immune response to infection via local tryptophan deprivation, active catabolite production, and non-enzymatic cell signaling. Whether fungal Idos have pleiotropic functions that impact on host-fungal physiology is unclear. Here, we show that Aspergillus fumigatus possesses three ido genes that are expressed under conditions of hypoxia or tryptophan abundance. Loss of these genes results in increased fungal pathogenicity and inflammation in a mouse model of aspergillosis, driven by an alternative tryptophan degradation pathway to indole derivatives and the host aryl hydrocarbon receptor. Fungal tryptophan metabolic pathways thus cooperate with the host xenobiotic response to shape host-microbe interactions in local tissue microenvironments.
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Affiliation(s)
- Teresa Zelante
- Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy.
| | - Tsokyi Choera
- Department of Medical Microbiology and Immunology, Department of Bacteriology, University of Wisconsin, Madison, WI, USA
| | - Anne Beauvais
- Unitè des Aspergillus, Pasteur Institute, 75724 Paris, France
| | - Francesca Fallarino
- Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy
| | - Giuseppe Paolicelli
- Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy
| | - Giuseppe Pieraccini
- Mass Spectrometry Centre (CISM), University of Florence, 50019 Florence, Italy
| | - Marco Pieroni
- P4T group, Department of Food and Drug, University of Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Claudia Galosi
- Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy
| | - Claudia Beato
- Interdepartmental Centre for Measures (CIM) "G. Casnati," University of Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy
| | - Antonella De Luca
- Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy
| | - Francesca Boscaro
- Mass Spectrometry Centre (CISM), University of Florence, 50019 Florence, Italy
| | - Riccardo Romoli
- Mass Spectrometry Centre (CISM), University of Florence, 50019 Florence, Italy
| | - Xin Liu
- Department of Medical Microbiology and Immunology, Department of Bacteriology, University of Wisconsin, Madison, WI, USA
| | - Adilia Warris
- MRC Centre for Medical Mycology, Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Paul E Verweij
- Department of Medical Microbiology, Centre of Expertise in Mycology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Eloise Ballard
- MRC Centre for Medical Mycology, Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Monica Borghi
- Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy
| | - Marilena Pariano
- Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy
| | - Gabriele Costantino
- P4T group, Department of Food and Drug, University of Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Mario Calvitti
- Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy
| | - Carmine Vacca
- Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy
| | - Vasilis Oikonomou
- Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy
| | - Marco Gargaro
- Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy
| | - Alicia Yoke Wei Wong
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A(∗)STAR), Singapore, Singapore
| | | | | | - Zdeněk Spáčil
- Research Centre for Toxic Compounds in the Environment (RECETOX), Brno, Czech Republic
| | - Paolo Puccetti
- Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy
| | - Jean-Paul Latgè
- Unitè des Aspergillus, Pasteur Institute, 75724 Paris, France
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, Department of Bacteriology, University of Wisconsin, Madison, WI, USA
| | - Luigina Romani
- Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy
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17
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Compare Catalase Activity Between Aspergillus flavus and A. fumigatus, Isolated from Clinical and Environmental Specimens. Jundishapur J Microbiol 2020. [DOI: 10.5812/jjm.103634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: Catalase enzyme is a potential virulence factor for Aspergillus species. Objectives: This study aimed to evaluate the catalase activity in conidium and mycelium of Aspergillus flavus and A. fumigatus isolated from environmental and clinical samples. Methods: Forty Aspergillus species (20 A. fumigatus and 20 A. flavus) were evaluated. Species were identified using the macroscopic and microscopic criteria of the isolates on culture media and the PCR-RFLP method, using the MwoI enzyme. The activity of the enzyme was evaluated using the Amplex red catalase assay kit. The Shapiro Wilk, Kolmogorov-Smirnov, Mann-Whitney, and Wilcoxon Signed Rank tests were used to analyze the data. Results: The mean conidial and mycelial catalase activities in A. flavus clinical and environmental isolates were 58.10, 57.80 mU/mL, and 1328.30, 531.60 mU/mL, respectively. In A. fumigatus clinical and environmental isolates, the activities were 61.10 and 61.40 mU/mL, and 1248.90 and 722.90 mU/mL, respectively. A significant difference was found between conidial and mycelial catalase activity in Aspergillus species (P = 0.01). The mycelial catalase activity of Aspergillus species isolated from clinical samples was higher than the environmental ones (A. flavus P = 0.01 and A. fumigatus P = 0.04). Conclusions: The mycelial catalase activity was higher than conidia. Clinical isolates of A. flavus had similar mycelium activity to A. fumigatus. By using the information provided in the present study, the severity of aspergillosis can be predicted, which paves the way for identifying new antifungal agents.
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18
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Chikashige Y, Kato H, Thornton M, Pepper W, Hilgers M, Cecil A, Asano I, Yamada H, Mori C, Brunkow C, Moravek C, Urano T, Singh CR, Asano K. Gcn2 eIF2α kinase mediates combinatorial translational regulation through nucleotide motifs and uORFs in target mRNAs. Nucleic Acids Res 2020; 48:8977-8992. [PMID: 32710633 PMCID: PMC7498311 DOI: 10.1093/nar/gkaa608] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/06/2020] [Accepted: 07/24/2020] [Indexed: 12/14/2022] Open
Abstract
The protein kinase Gcn2 is a central transducer of nutritional stress signaling important for stress adaptation by normal cells and the survival of cancer cells. In response to nutrient deprivation, Gcn2 phosphorylates eIF2α, thereby repressing general translation while enhancing translation of specific mRNAs with upstream ORFs (uORFs) situated in their 5'-leader regions. Here we performed genome-wide measurements of mRNA translation during histidine starvation in fission yeast Schizosaccharomyces pombe. Polysome analyses were combined with microarray measurements to identify gene transcripts whose translation was up-regulated in response to the stress in a Gcn2-dependent manner. We determined that translation is reprogrammed to enhance RNA metabolism and chromatin regulation and repress ribosome synthesis. Interestingly, translation of intron-containing mRNAs was up-regulated. The products of the regulated genes include additional eIF2α kinase Hri2 amplifying the stress signaling and Gcn5 histone acetyl transferase and transcription factors, together altering genome-wide transcription. Unique dipeptide-coding uORFs and nucleotide motifs, such as '5'-UGA(C/G)GG-3', are found in 5' leader regions of regulated genes and shown to be responsible for translational control.
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Affiliation(s)
- Yuji Chikashige
- Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe, Hyogo 651-2492, Japan
| | - Hiroaki Kato
- Department of Biochemistry, Shimane University School of Medicine, Izumo, Shimane 693-8501, Japan
| | - Mackenzie Thornton
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Whitney Pepper
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Madelyn Hilgers
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Ariana Cecil
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Izumi Asano
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Haana Yamada
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
- Department of Advanced Transdisciplinary Sciences, Faculty of Advanced Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Chie Mori
- Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe, Hyogo 651-2492, Japan
| | - Cheyenne Brunkow
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Carter Moravek
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Takeshi Urano
- Department of Biochemistry, Shimane University School of Medicine, Izumo, Shimane 693-8501, Japan
| | - Chingakham Ranjit Singh
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Katsura Asano
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
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19
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Milhomem Cruz-Leite VR, Salem-Izacc SM, Novaes E, Neves BJ, de Almeida Brito W, O'Hara Souza Silva L, Paccez JD, Parente-Rocha JA, Pereira M, Maria de Almeida Soares C, Borges CL. Nitrogen Catabolite Repression in members of Paracoccidioides complex. Microb Pathog 2020; 149:104281. [PMID: 32585293 DOI: 10.1016/j.micpath.2020.104281] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/24/2020] [Accepted: 05/25/2020] [Indexed: 01/15/2023]
Abstract
Paracoccidioides complex is a genus that comprises pathogenic fungi which are responsible by systemic disease Paracoccidioidomycosis. In host tissues, pathogenic fungi need to acquire nutrients in order to survive, making the uptake of nitrogen essential for their establishment and dissemination. Nitrogen utilization is employed by the alleviation of Nitrogen Catabolite Repression (NCR) which ensures the use of non-preferential or alternative nitrogen sources when preferential sources are not available. NCR is controlled by GATA transcription factors which act through GATA binding sites on promoter regions in NCR-sensitive genes. This process is responsible for encoding proteins involved with the scavenge, uptake and catabolism of a wide variety of non-preferential nitrogen sources. In this work, we predict the existence of AreA GATA transcription factor and feature the zinc finger domain by three-dimensional structure in Paracoccidioides. Furthermore, we demonstrate the putative genes involved with NCR response by means of in silico analysis. The gene expression profile under NCR conditions was evaluated. Demonstrating that P. lutzii supported transcriptional regulation and alleviated NCR in non-preferential nitrogen-dependent medium. The elucidation of NCR in members of Paracoccidioides complex will provide new knowledge about survival, dissemination and virulence for these pathogens with regard to nitrogen-scavenging strategies in the interactions of host-pathogens.
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Affiliation(s)
| | - Silvia Maria Salem-Izacc
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
| | - Evandro Novaes
- Escola de Agronomia, Setor de Melhoramento de Plantas, Universidade Federal de Goiás, Campus II Samambaia, Rodovia Goiânia a Nova Veneza, Goiás, Brazil.
| | - Bruno Junior Neves
- Centro Universitário de Anápolis - UniEVANGÉLICA, Anápolis, Goiás, Brazil.
| | - Wesley de Almeida Brito
- Centro Universitário de Anápolis - UniEVANGÉLICA, Anápolis, Goiás, Brazil; Universidade Estadual de Goiás - UEG - CCET, Anápolis, Goiás, Brazil.
| | - Lana O'Hara Souza Silva
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
| | - Juliano Domiraci Paccez
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
| | - Juliana Alves Parente-Rocha
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
| | - Maristela Pereira
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
| | - Célia Maria de Almeida Soares
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
| | - Clayton Luiz Borges
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
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20
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Absence of AfuXpot, the yeast Los1 homologue, limits Aspergillus fumigatus growth under amino acid deprived condition. World J Microbiol Biotechnol 2020; 36:28. [PMID: 32002680 DOI: 10.1007/s11274-020-2805-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 01/22/2020] [Indexed: 02/06/2023]
Abstract
In Saccharomyces cerevisiae, los1 encodes a nuclear tRNA exporter. Despite the non-essentiality, the deletion of los1 has been shown to extend replicative life span in yeast. Here, we characterized AfuXpot, the los1 homologue in human pathogen Aspergillus fumigatus and found that it is continuously expressed during fungal growth. Microscopic examination of an AfuXpot-GFP-expressing transformant confirmed the nuclear localization of the fusion protein. The targeted gene deletion affirmed the non-essential role of AfuXpot in hyphal growth and sporulation. However, the growth of the deletion mutant was affected by amino acid, but not glucose, deprivation. The susceptibility of the deletant strain to protein and DNA/RNA synthesis inhibitors was also altered. Using bioinformatics tools, some transcription factor binding sites were predicted in AfuXpot promoter. Expression analyses of potential AfuXpot-interacting genes showed a marked down-regulation of sfp1 and mtr10 homologues in ΔAfuXpot strain. Our data demonstrates some conserved aspects of AfuXpot as a tRNA exporter in A. fumigatus.
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21
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Abstract
Aspergillus fumigatus is a saprotrophic fungus; its primary habitat is the soil. In its ecological niche, the fungus has learned how to adapt and proliferate in hostile environments. This capacity has helped the fungus to resist and survive against human host defenses and, further, to be responsible for one of the most devastating lung infections in terms of morbidity and mortality. In this review, we will provide (i) a description of the biological cycle of A. fumigatus; (ii) a historical perspective of the spectrum of aspergillus disease and the current epidemiological status of these infections; (iii) an analysis of the modes of immune response against Aspergillus in immunocompetent and immunocompromised patients; (iv) an understanding of the pathways responsible for fungal virulence and their host molecular targets, with a specific focus on the cell wall; (v) the current status of the diagnosis of different clinical syndromes; and (vi) an overview of the available antifungal armamentarium and the therapeutic strategies in the clinical context. In addition, the emergence of new concepts, such as nutritional immunity and the integration and rewiring of multiple fungal metabolic activities occurring during lung invasion, has helped us to redefine the opportunistic pathogenesis of A. fumigatus.
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Affiliation(s)
- Jean-Paul Latgé
- School of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Georgios Chamilos
- School of Medicine, University of Crete, Heraklion, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Heraklion, Crete, Greece
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22
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Role of Amino Acid Metabolism in the Virulence of Human Pathogenic Fungi. CURRENT CLINICAL MICROBIOLOGY REPORTS 2019. [DOI: 10.1007/s40588-019-00124-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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23
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Zhang X, Xu M, Wu J, Dong W, Chen D, Wang L, Chi Y. Draft Genome Sequence of Phoma arachidicola Wb2 Causing Peanut Web Blotch in China. Curr Microbiol 2018; 76:200-206. [PMID: 30535834 DOI: 10.1007/s00284-018-1612-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 12/05/2018] [Indexed: 12/22/2022]
Abstract
Peanut web blotch, a peanut disease with both web and blotch symptom leaflets, is an emerging threat for peanut cultivation worldwide and one of the most important fungal diseases in China. However, the limited pieces of information in genomic resources and pathogenesis are the major constraints to integrated disease management. The genome contains a large number of pathogenicity-related genes, but the genomic information of the pathogen is still blank. Considering this fact, current study presented the draft genome sequence of a Phoma arachidicola isolate named Wb2. Strain Wb2 was isolated from peanut leaves with typical web blotch symptoms, and identified as Phoma arachidicola based on morphological characteristics and phylogenic analysis using ITS sequence. The draft genome of Wb2 is about 34.11 Mb and contains 37330 open reading frames (ORFs), with G + C content 49.23%. The strain Wb2 has an abundance of secreted oxidases, peroxidases, and carbohydrate-active enzymes for degrading cell wall polysaccharides and penetrating into the host tissue. The genome information of Wb2 will help to better understand the mechanisms of interaction between P. arachidicola and peanuts. Furthermore, the genome-based plant-pathogen interaction analysis will provide clues for disease control, which is essential to ensure peanut production and food security.
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Affiliation(s)
- Xia Zhang
- Shandong Peanut Research Institute, Qingdao, Shandong, People's Republic of China
| | - Manlin Xu
- Shandong Peanut Research Institute, Qingdao, Shandong, People's Republic of China
| | - Juxiang Wu
- Shandong Peanut Research Institute, Qingdao, Shandong, People's Republic of China
| | - Weibo Dong
- Shandong Peanut Research Institute, Qingdao, Shandong, People's Republic of China
| | - Dianxu Chen
- Shandong Peanut Research Institute, Qingdao, Shandong, People's Republic of China
| | - Lei Wang
- Shandong Peanut Research Institute, Qingdao, Shandong, People's Republic of China
| | - Yucheng Chi
- Shandong Peanut Research Institute, Qingdao, Shandong, People's Republic of China.
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Choera T, Zelante T, Romani L, Keller NP. A Multifaceted Role of Tryptophan Metabolism and Indoleamine 2,3-Dioxygenase Activity in Aspergillus fumigatus-Host Interactions. Front Immunol 2018; 8:1996. [PMID: 29403477 PMCID: PMC5786828 DOI: 10.3389/fimmu.2017.01996] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 12/22/2017] [Indexed: 12/19/2022] Open
Abstract
Aspergillus fumigatus is the most prevalent filamentous fungal pathogen of humans, causing either severe allergic bronchopulmonary aspergillosis or often fatal invasive pulmonary aspergillosis (IPA) in individuals with hyper- or hypo-immune deficiencies, respectively. Disease is primarily initiated upon the inhalation of the ubiquitous airborne conidia—the initial inoculum produced by A. fumigatus—which are complete developmental units with an ability to exploit diverse environments, ranging from agricultural composts to animal lungs. Upon infection, conidia initially rely on their own metabolic processes for survival in the host’s lungs, a nutritionally limiting environment. One such nutritional limitation is the availability of aromatic amino acids (AAAs) as animals lack the enzymes to synthesize tryptophan (Trp) and phenylalanine and only produce tyrosine from dietary phenylalanine. However, A. fumigatus produces all three AAAs through the shikimate–chorismate pathway, where they play a critical role in fungal growth and development and in yielding many downstream metabolites. The downstream metabolites of Trp in A. fumigatus include the immunomodulatory kynurenine derived from indoleamine 2,3-dioxygenase (IDO) and toxins such as fumiquinazolines, gliotoxin, and fumitremorgins. Host IDO activity and/or host/microbe-derived kynurenines are increasingly correlated with many Aspergillus diseases including IPA and infections of chronic granulomatous disease patients. In this review, we will describe the potential metabolic cross talk between the host and the pathogen, specifically focusing on Trp metabolism, the implications for therapeutics, and the recent studies on the coevolution of host and microbe IDO activation in regulating inflammation, while controlling infection.
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Affiliation(s)
- Tsokyi Choera
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States
| | - Teresa Zelante
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Luigina Romani
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States.,Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
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Amarsaikhan N, Albrecht-Eckardt D, Sasse C, Braus GH, Ogel ZB, Kniemeyer O. Proteomic profiling of the antifungal drug response of Aspergillus fumigatus to voriconazole. Int J Med Microbiol 2017; 307:398-408. [DOI: 10.1016/j.ijmm.2017.07.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 06/29/2017] [Accepted: 07/27/2017] [Indexed: 12/18/2022] Open
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Abstract
Aspergillus fumigatus is an environmental filamentous fungus that can cause life-threatening disease in immunocompromised individuals. The interactions between A. fumigatus and the host environment are dynamic and complex. The host immune system needs to recognize the distinct morphological forms of A. fumigatus to control fungal growth and prevent tissue invasion, whereas the fungus requires nutrients and needs to adapt to the hostile environment by escaping immune recognition and counteracting host responses. Understanding these highly dynamic interactions is necessary to fully understand the pathogenesis of aspergillosis and to facilitate the design of new therapeutics to overcome the morbidity and mortality caused by A. fumigatus. In this Review, we describe how A. fumigatus adapts to environmental change, the mechanisms of host defence, and our current knowledge of the interplay between the host immune response and the fungus.
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Antifungal Resistance, Metabolic Routes as Drug Targets, and New Antifungal Agents: An Overview about Endemic Dimorphic Fungi. Mediators Inflamm 2017; 2017:9870679. [PMID: 28694566 PMCID: PMC5485324 DOI: 10.1155/2017/9870679] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/28/2017] [Accepted: 05/23/2017] [Indexed: 12/30/2022] Open
Abstract
Diseases caused by fungi can occur in healthy people, but immunocompromised patients are the major risk group for invasive fungal infections. Cases of fungal resistance and the difficulty of treatment make fungal infections a public health problem. This review explores mechanisms used by fungi to promote fungal resistance, such as the mutation or overexpression of drug targets, efflux and degradation systems, and pleiotropic drug responses. Alternative novel drug targets have been investigated; these include metabolic routes used by fungi during infection, such as trehalose and amino acid metabolism and mitochondrial proteins. An overview of new antifungal agents, including nanostructured antifungals, as well as of repositioning approaches is discussed. Studies focusing on the development of vaccines against antifungal diseases have increased in recent years, as these strategies can be applied in combination with antifungal therapy to prevent posttreatment sequelae. Studies focused on the development of a pan-fungal vaccine and antifungal drugs can improve the treatment of immunocompromised patients and reduce treatment costs.
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Bultman KM, Kowalski CH, Cramer RA. Aspergillus fumigatus virulence through the lens of transcription factors. Med Mycol 2016; 55:24-38. [PMID: 27816905 DOI: 10.1093/mmy/myw120] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 08/19/2016] [Accepted: 10/17/2016] [Indexed: 02/07/2023] Open
Abstract
Invasive aspergillosis (IA), most commonly caused by the filamentous fungus Aspergillus fumigatus, occurs in immune compromised individuals. The ability of A. fumigatus to proliferate in a multitude of environments is hypothesized to contribute to its pathogenicity and virulence. Transcription factors (TF) have long been recognized as critical proteins for fungal pathogenicity, as many are known to play important roles in the transcriptional regulation of pathways implicated in virulence. Such pathways include regulation of conidiation and development, adhesion, nutrient acquisition, adaptation to environmental stress, and interactions with the host immune system among others. In both murine and insect models of IA, TF loss of function in A. fumigatus results in cases of hyper- and hypovirulence as determined through host survival, fungal burden, and immune response analyses. Consequently, the study of specific TFs in A. fumigatus has revealed important insights into mechanisms of pathogenicity and virulence. Although in vitro studies have identified virulence-related functions of specific TFs, the full picture of their in vivo functions remain largely enigmatic and an exciting area of current research. Moreover, the vast majority of TFs remain to be characterized and studied in this important human pathogen. Here in this mini-review we provide an overview of selected TFs in A. fumigatus and their contribution to our understanding of this important human pathogen's pathogenicity and virulence.
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Affiliation(s)
- Katherine M Bultman
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Caitlin H Kowalski
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Robert A Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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Pais P, Costa C, Cavalheiro M, Romão D, Teixeira MC. Transcriptional Control of Drug Resistance, Virulence and Immune System Evasion in Pathogenic Fungi: A Cross-Species Comparison. Front Cell Infect Microbiol 2016; 6:131. [PMID: 27812511 PMCID: PMC5072224 DOI: 10.3389/fcimb.2016.00131] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/29/2016] [Indexed: 12/26/2022] Open
Abstract
Transcription factors are key players in the control of the activation or repression of gene expression programs in response to environmental stimuli. The study of regulatory networks taking place in fungal pathogens is a promising research topic that can help in the fight against these pathogens by targeting specific fungal pathways as a whole, instead of targeting more specific effectors of virulence or drug resistance. This review is focused on the analysis of regulatory networks playing a central role in the referred mechanisms in the human fungal pathogens Aspergillus fumigatus, Cryptococcus neoformans, Candida albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis. Current knowledge on the activity of the transcription factors characterized in each of these pathogenic fungal species will be addressed. Particular focus is given to their mechanisms of activation, regulatory targets and phenotypic outcome. The review further provides an evaluation on the conservation of transcriptional circuits among different fungal pathogens, highlighting the pathways that translate common or divergent traits among these species in what concerns their drug resistance, virulence and host immune evasion features. It becomes evident that the regulation of transcriptional networks is complex and presents significant variations among different fungal pathogens. Only the oxidative stress regulators Yap1 and Skn7 are conserved among all studied species; while some transcription factors, involved in nutrient homeostasis, pH adaptation, drug resistance and morphological switching are present in several, though not all species. Interestingly, in some cases not very homologous transcription factors display orthologous functions, whereas some homologous proteins have diverged in terms of their function in different species. A few cases of species specific transcription factors are also observed.
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Affiliation(s)
- Pedro Pais
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
| | - Catarina Costa
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
| | - Mafalda Cavalheiro
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
| | - Daniela Romão
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
| | - Miguel C Teixeira
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
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Heterogeneity among Isolates Reveals that Fitness in Low Oxygen Correlates with Aspergillus fumigatus Virulence. mBio 2016; 7:mBio.01515-16. [PMID: 27651366 PMCID: PMC5040115 DOI: 10.1128/mbio.01515-16] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED Previous work has shown that environmental and clinical isolates of Aspergillus fumigatus represent a diverse population that occupies a variety of niches, has extensive genetic diversity, and exhibits virulence heterogeneity in a number of animal models of invasive pulmonary aspergillosis (IPA). However, mechanisms explaining differences in virulence among A. fumigatus isolates remain enigmatic. Here, we report a significant difference in virulence of two common lab strains, CEA10 and AF293, in the murine triamcinolone immunosuppression model of IPA, in which we previously identified severe low oxygen microenvironments surrounding fungal lesions. Therefore, we hypothesize that the ability to thrive within these lesions of low oxygen promotes virulence of A. fumigatus in this model. To test this hypothesis, we performed in vitro fitness and in vivo virulence analyses in the triamcinolone murine model of IPA with 14 environmental and clinical isolates of A. fumigatus Among these isolates, we observed a strong correlation between fitness in low oxygen in vitro and virulence. In further support of our hypothesis, experimental evolution of AF293, a strain that exhibits reduced fitness in low oxygen and reduced virulence in the triamcinolone model of IPA, results in a strain (EVOL20) that has increased hypoxia fitness and a corresponding increase in virulence. Thus, the ability to thrive in low oxygen correlates with virulence of A. fumigatus isolates in the context of steroid-mediated murine immunosuppression. IMPORTANCE Aspergillus fumigatus occupies multiple environmental niches, likely contributing to the genotypic and phenotypic heterogeneity among isolates. Despite reports of virulence heterogeneity, pathogenesis studies often utilize a single strain for the identification and characterization of virulence and immunity factors. Here, we describe significant variation between A. fumigatus isolates in hypoxia fitness and virulence, highlighting the advantage of including multiple strains in future studies. We also illustrate that hypoxia fitness correlates strongly with increased virulence exclusively in the nonleukopenic murine triamcinolone immunosuppression model of IPA. Through an experimental evolution experiment, we observe that chronic hypoxia exposure results in increased virulence of A. fumigatus We describe here the first observation of a model-specific virulence phenotype correlative with in vitro fitness in hypoxia and pave the way for identification of hypoxia-mediated mechanisms of virulence in the fungal pathogen A. fumigatus.
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Amich J, Bignell E. Amino acid biosynthetic routes as drug targets for pulmonary fungal pathogens: what is known and why do we need to know more? Curr Opin Microbiol 2016; 32:151-158. [DOI: 10.1016/j.mib.2016.06.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/07/2016] [Accepted: 06/09/2016] [Indexed: 11/29/2022]
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Exploration of Sulfur Assimilation of Aspergillus fumigatus Reveals Biosynthesis of Sulfur-Containing Amino Acids as a Virulence Determinant. Infect Immun 2016; 84:917-929. [PMID: 26787716 DOI: 10.1128/iai.01124-15] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 01/07/2016] [Indexed: 12/17/2022] Open
Abstract
Fungal infections are of major relevance due to the increased numbers of immunocompromised patients, frequently delayed diagnosis, and limited therapeutics. To date, the growth and nutritional requirements of fungi during infection, which are relevant for invasion of the host, are poorly understood. This is particularly true for invasive pulmonary aspergillosis, as so far, sources of (macro)elements that are exploited during infection have been identified to only a limited extent. Here, we have investigated sulfur (S) utilization by the human-pathogenic mold Aspergillus fumigatus during invasive growth. Our data reveal that inorganic S compounds or taurine is unlikely to serve as an S source during invasive pulmonary aspergillosis since a sulfate transporter mutant strain and a sulfite reductase mutant strain are fully virulent. In contrast, the S-containing amino acid cysteine is limiting for fungal growth, as proven by the reduced virulence of a cysteine auxotroph. Moreover, phenotypic characterization of this strain further revealed the robustness of the subordinate glutathione redox system. Interestingly, we demonstrate that methionine synthase is essential for A. fumigatus virulence, defining the biosynthetic route of this proteinogenic amino acid as a potential antifungal target. In conclusion, we provide novel insights into the nutritional requirements ofA. fumigatus during pathogenesis, a prerequisite to understanding and fighting infection.
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The contribution of Aspergillus fumigatus stress responses to virulence and antifungal resistance. J Microbiol 2016; 54:243-53. [PMID: 26920884 DOI: 10.1007/s12275-016-5510-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 10/21/2015] [Accepted: 10/22/2015] [Indexed: 10/22/2022]
Abstract
Invasive aspergillosis has emerged as one of the most common life-threatening fungal disease of humans. The emergence of antifungal resistant pathogens represents a current and increasing threat to society. In turn, new strategies to combat fungal infection are urgently required. Fungal adaptations to stresses experienced within the human host are a prerequisite for the survival and virulence strategies of the pathogen. Here, we review the latest information on the signalling pathways in Aspergillus fumigatus that contribute to stress adaptations and virulence, while highlighting their potential as targets for the development of novel combinational antifungal therapies.
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Dietl AM, Amich J, Leal S, Beckmann N, Binder U, Beilhack A, Pearlman E, Haas H. Histidine biosynthesis plays a crucial role in metal homeostasis and virulence of Aspergillus fumigatus. Virulence 2016; 7:465-76. [PMID: 26854126 PMCID: PMC4871644 DOI: 10.1080/21505594.2016.1146848] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Aspergillus fumigatus is the most prevalent airborne fungal pathogen causing invasive fungal infections in immunosuppressed individuals. The histidine biosynthetic pathway is found in bacteria, archaebacteria, lower eukaryotes, and plants, but is absent in mammals. Here we demonstrate that deletion of the gene encoding imidazoleglycerol-phosphate dehydratase (HisB) in A. fumigatus causes (i) histidine auxotrophy, (ii) decreased resistance to both starvation and excess of various heavy metals, including iron, copper and zinc, which play a pivotal role in antimicrobial host defense, (iii) attenuation of pathogenicity in 4 virulence models: murine pulmonary infection, murine systemic infection, murine corneal infection, and wax moth larvae. In agreement with the in vivo importance of histidine biosynthesis, the HisB inhibitor 3-amino-1,2,4-triazole reduced the virulence of the A. fumigatus wild type and histidine supplementation partially rescued virulence of the histidine-auxotrophic mutant in the wax moth model. Taken together, this study reveals limited histidine availability in diverse A. fumigatus host niches, a crucial role for histidine in metal homeostasis, and the histidine biosynthetic pathway as being an attractive target for development of novel antifungal therapy approaches.
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Affiliation(s)
- Anna-Maria Dietl
- a Division of Molecular Biology, Biocenter, Medical University of Innsbruck , Innsbruck , Austria
| | - Jorge Amich
- b IZKF Forschergruppe für Experimentelle Stammzelltransplantation, Medizinische Klinik und Poliklinik II & Universitäts-Kinderklinik , Würzburg , Germany
| | - Sixto Leal
- c Department of Ophthalmology and Visual Sciences , Case Western Reserve University , Cleveland , OH , USA
| | - Nicola Beckmann
- a Division of Molecular Biology, Biocenter, Medical University of Innsbruck , Innsbruck , Austria
| | - Ulrike Binder
- d Division of Hygiene & Medical Microbiology, Medical University of Innsbruck , Innsbruck , Austria
| | - Andreas Beilhack
- b IZKF Forschergruppe für Experimentelle Stammzelltransplantation, Medizinische Klinik und Poliklinik II & Universitäts-Kinderklinik , Würzburg , Germany
| | - Eric Pearlman
- c Department of Ophthalmology and Visual Sciences , Case Western Reserve University , Cleveland , OH , USA
| | - Hubertus Haas
- a Division of Molecular Biology, Biocenter, Medical University of Innsbruck , Innsbruck , Austria
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Cramer RA. In vivo veritas: Aspergillus fumigatus proliferation and pathogenesis--conditionally speaking. Virulence 2016; 7:7-10. [PMID: 26695225 PMCID: PMC4871685 DOI: 10.1080/21505594.2015.1134074] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 12/14/2015] [Accepted: 12/16/2015] [Indexed: 12/20/2022] Open
Affiliation(s)
- Robert A Cramer
- Department of Microbiology and Immunology; Geisel School of Medicine at Dartmouth; Hanover, NH USA
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Wang PM, Choera T, Wiemann P, Pisithkul T, Amador-Noguez D, Keller NP. TrpE feedback mutants reveal roadblocks and conduits toward increasing secondary metabolism in Aspergillus fumigatus. Fungal Genet Biol 2015; 89:102-113. [PMID: 26701311 DOI: 10.1016/j.fgb.2015.12.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 11/23/2015] [Accepted: 12/05/2015] [Indexed: 12/11/2022]
Abstract
Small peptides formed from non-ribosomal peptide synthetases (NRPS) are bioactive molecules produced by many fungi including the genus Aspergillus. A subset of NRPS utilizes tryptophan and its precursor, the non-proteinogenic amino acid anthranilate, in synthesis of various metabolites such as Aspergillus fumigatus fumiquinazolines (Fqs) produced by the fmq gene cluster. The A. fumigatus genome contains two putative anthranilate synthases - a key enzyme in conversion of anthranilic acid to tryptophan - one beside the fmq cluster and one in a region of co-linearity with other Aspergillus spp. Only the gene found in the co-linear region, trpE, was involved in tryptophan biosynthesis. We found that site-specific mutations of the TrpE feedback domain resulted in significantly increased production of anthranilate, tryptophan, p-aminobenzoate and fumiquinazolines FqF and FqC. Supplementation with tryptophan restored metabolism to near wild type levels in the feedback mutants and suggested that synthesis of the tryptophan degradation product kynurenine could negatively impact Fq synthesis. The second putative anthranilate synthase gene next to the fmq cluster was termed icsA for its considerable identity to isochorismate synthases in bacteria. Although icsA had no impact on A. fumigatus Fq production, deletion and over-expression of icsA increased and decreased respectively aromatic amino acid levels suggesting that IcsA can draw from the cellular chorismate pool.
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Affiliation(s)
- Pin-Mei Wang
- Ocean College, Zhejiang University, Hangzhou 310058, Zhejiang Province, PR China
| | - Tsokyi Choera
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, USA
| | - Philipp Wiemann
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, USA
| | | | | | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, USA; Department of Bacteriology, University of Wisconsin, Madison, USA.
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Sasse A, Hamer SN, Amich J, Binder J, Krappmann S. Mutant characterization and in vivo conditional repression identify aromatic amino acid biosynthesis to be essential for Aspergillus fumigatus virulence. Virulence 2015; 7:56-62. [PMID: 26605426 PMCID: PMC4871646 DOI: 10.1080/21505594.2015.1109766] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 10/07/2015] [Accepted: 10/12/2015] [Indexed: 10/22/2022] Open
Abstract
Pathogenicity of the saprobe Aspergillus fumigatus strictly depends on nutrient acquisition during infection, as fungal growth determines colonisation and invasion of a susceptible host. Primary metabolism has to be considered as a valid target for antimycotic therapy, based on the fact that several fungal anabolic pathways are not conserved in higher eukaryotes. To test whether fungal proliferation during invasive aspergillosis relies on endogenous biosynthesis of aromatic amino acids, defined auxotrophic mutants of A. fumigatus were generated and assessed for their infectious capacities in neutropenic mice and found to be strongly attenuated in virulence. Moreover, essentiality of the complete biosynthetic pathway could be demonstrated, corroborated by conditional gene expression in infected animals and inhibitor studies. This brief report not only validates the aromatic amino acid biosynthesis pathway of A. fumigatus to be a promising antifungal target but furthermore demonstrates feasibility of conditional gene expression in a murine infection model of aspergillosis.
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Affiliation(s)
- Anna Sasse
- Research Center for Infectious Diseases; Julius-Maximilians-Universität Würzburg; Würzburg, Germany
| | - Stefanie N Hamer
- Research Center for Infectious Diseases; Julius-Maximilians-Universität Würzburg; Würzburg, Germany
- Present address: Institute of Plant Biology and Biotechnology; University of Münster; Müunster, Germany
| | - Jorge Amich
- Department of Medicine II and Center for Interdisciplinary Clinical Research; University Hospital Würzburg; Würzburg, Germany
| | - Jasmin Binder
- Mikrobiologisches Institut - Klinische Mikrobiologie: Immunologie und Hygiene; Universitätsklinikum Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg; Erlangen, Germany
| | - Sven Krappmann
- Research Center for Infectious Diseases; Julius-Maximilians-Universität Würzburg; Würzburg, Germany
- Mikrobiologisches Institut - Klinische Mikrobiologie: Immunologie und Hygiene; Universitätsklinikum Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg; Erlangen, Germany
- Medical Immunology Campus Erlangen; Friedrich-Alexander University Erlangen-Nürnberg; Erlangen, Germany
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Irmer H, Tarazona S, Sasse C, Olbermann P, Loeffler J, Krappmann S, Conesa A, Braus GH. RNAseq analysis of Aspergillus fumigatus in blood reveals a just wait and see resting stage behavior. BMC Genomics 2015; 16:640. [PMID: 26311470 PMCID: PMC4551469 DOI: 10.1186/s12864-015-1853-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 08/17/2015] [Indexed: 12/20/2022] Open
Abstract
Background Invasive aspergillosis is started after germination of Aspergillus fumigatus conidia that are inhaled by susceptible individuals. Fungal hyphae can grow in the lung through the epithelial tissue and disseminate hematogenously to invade into other organs. Low fungaemia indicates that fungal elements do not reside in the bloodstream for long. Results We analyzed whether blood represents a hostile environment to which the physiology of A. fumigatus has to adapt. An in vitro model of A. fumigatus infection was established by incubating mycelium in blood. Our model allowed to discern the changes of the gene expression profile of A. fumigatus at various stages of the infection. The majority of described virulence factors that are connected to pulmonary infections appeared not to be activated during the blood phase. Three active processes were identified that presumably help the fungus to survive the blood environment in an advanced phase of the infection: iron homeostasis, secondary metabolism, and the formation of detoxifying enzymes. Conclusions We propose that A. fumigatus is hardly able to propagate in blood. After an early stage of sensing the environment, virtually all uptake mechanisms and energy-consuming metabolic pathways are shut-down. The fungus appears to adapt by trans-differentiation into a resting mycelial stage. This might reflect the harsh conditions in blood where A. fumigatus cannot take up sufficient nutrients to establish self-defense mechanisms combined with significant growth. Electronic supplementary material The online version of this article (doi10.1186/s12864-015-1853-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Henriette Irmer
- Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Grisebachstraße 8, D-37077, Göttingen, Germany.
| | - Sonia Tarazona
- Genomics of Gene Expression Lab, Prince Felipe Research Center, Av. Eduardo Primo Yufera 3, 46012, Valencia, Spain.
| | - Christoph Sasse
- Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Grisebachstraße 8, D-37077, Göttingen, Germany.
| | - Patrick Olbermann
- Research Center for Infectious Diseases, Julius-Maximilians University Würzburg, Würzburg, Germany.
| | - Jürgen Loeffler
- Laboratory WÜ4i, Medical Clinic and Policlinic II, University Clinic Würzburg, Würzburg, Germany.
| | - Sven Krappmann
- Research Center for Infectious Diseases, Julius-Maximilians University Würzburg, Würzburg, Germany. .,Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinik Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
| | - Ana Conesa
- Genomics of Gene Expression Lab, Prince Felipe Research Center, Av. Eduardo Primo Yufera 3, 46012, Valencia, Spain. .,Department of Microbiology and Cell Science, Institute for Food and Agricultura Sciences, University of Florida at Gainesville, Gainesville, FL, USA.
| | - Gerhard H Braus
- Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Grisebachstraße 8, D-37077, Göttingen, Germany.
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Gressler M, Meyer F, Heine D, Hortschansky P, Hertweck C, Brock M. Phytotoxin production in Aspergillus terreus is regulated by independent environmental signals. eLife 2015; 4. [PMID: 26173180 PMCID: PMC4528345 DOI: 10.7554/elife.07861] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 07/13/2015] [Indexed: 01/09/2023] Open
Abstract
Secondary metabolites have a great potential as pharmaceuticals, but there are only a few examples where regulation of gene cluster expression has been correlated with ecological and physiological relevance for the producer. Here, signals, mediators, and biological effects of terrein production were studied in the fungus Aspergillus terreus to elucidate the contribution of terrein to ecological competition. Terrein causes fruit surface lesions and inhibits plant seed germination. Additionally, terrein is moderately antifungal and reduces ferric iron, thereby supporting growth of A. terreus under iron starvation. In accordance, the lack of nitrogen or iron or elevated methionine levels induced terrein production and was dependent on either the nitrogen response regulators AreA and AtfA or the iron response regulator HapX. Independent signal transduction allows complex sensing of the environment and, combined with its broad spectrum of biological activities, terrein provides a prominent example of adapted secondary metabolite production in response to environmental competition. DOI:http://dx.doi.org/10.7554/eLife.07861.001 Organisms produce a wide variety of small molecules called metabolites through the break down of food and other chemical reactions. Some of these molecules—known as primary metabolites—are required for growth, reproduction and other vital processes. Other molecules called secondary metabolites are not strictly required by the organism, but generally have other roles that may improve the individual’s ability to survive and reproduce. Fungi and other microbes produce a large variety of secondary metabolites, many of which are used as medicines to treat diseases in humans and other animals. For example, a molecule called lovastatin—which is produced by a fungus known as Aspergillus terreus—can reduce a human patient's risk of heart disease. However, it is not known what role many secondary metabolites play in the microbe that produced them. A. terreus lives in the soil, but it can also infect plants and animals. In addition to lovastatin, it also makes another secondary metabolite called terrein. A recent study identified the genes responsible for making terrein, and discovered that this molecule is harmful to plant cells and may help the fungus to colonize and thrive in the area immediately around plant roots, which is known as the rhizosphere. Here, Gressler et al. studied how terrein may help the fungus to cope with competitors in this environment. The experiments show that terrein increases the availability of iron and inhibits the growth of competing microbes. A shortage of iron or nitrogen-containing nutrients can stimulate the fungus to produce terrein, and elevated levels of a molecule called methionine have the same effect. These conditions are commonly found in the rhizosphere and further experiments identified several proteins in the fungus that are required for sensing them. Gressler et al.'s findings suggest that terrein helps to ensure that the fungus has sufficient nitrogen and iron to thrive in the rhizosphere. Also, this study confirms that the production of secondary metabolites in microbes can happen in response to elaborate cues from the environment, which may explain why only a limited number of secondary metabolites are produced by microbes when they are grown in the laboratory. Future studies will analyze other ways to activate the production of secondary metabolites outside of the microbe's normal environment, which may lead to the discovery of new important drugs. DOI:http://dx.doi.org/10.7554/eLife.07861.002
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Affiliation(s)
- Markus Gressler
- Microbial Biochemistry and Physiology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Florian Meyer
- Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Daniel Heine
- Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Peter Hortschansky
- Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Christian Hertweck
- Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Matthias Brock
- Institute for Microbiology, Friedrich Schiller University, Jena, Germany.,Fungal Genetics and Biology Group, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
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Kong S, Park SY, Lee YH. Systematic characterization of the bZIP transcription factor gene family in the rice blast fungus, Magnaporthe oryzae. Environ Microbiol 2014; 17:1425-43. [PMID: 25314920 DOI: 10.1111/1462-2920.12633] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Revised: 09/10/2014] [Accepted: 09/10/2014] [Indexed: 01/26/2023]
Abstract
Regulatory roles of the basic leucine zipper (bZIP) transcription factors (TFs) in fungi have been identified in diverse cellular processes such as development, nutrient utilization and various stress responses. In this study, the 22 Magnaporthe oryzae genes encoding bZIP TFs were systematically characterized. Phylogenetic analysis of fungal bZIP TFs revealed that seven MobZIPs are Magnaporthe-specific, while others belongs to 15 clades of orthologous Ascomycota genes. Expression patterns of MobZIPs under various conditions showed that they are highly stress responsive. We generated deletion mutants for 13 MobZIPs: nine with orthologues in other fungal species and four Magnaporthe-specific ones. Seven of them exhibited defects in mycelial growth, development and/or pathogenicity. Consistent with the conserved functions of the orthologues, MobZIP22 and MobZIP13 played a role in sulfur metabolism and iron homeostasis respectively. Along with MobZIP22 and MobZIP13, one Magnaporthe-specific gene, MobZIP11 is essential for pathogenicity in a reactive oxygen species-dependent manner. Taken together, our results will contribute to understanding the regulatory mechanisms of the bZIP TF gene family in fungal development, adaptation to environmental stresses and pathogenicity in the rice blast fungus.
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Affiliation(s)
- Sunghyung Kong
- Department of Agricultural Biotechnology, Center for Fungal Genetic Resources, and Center for Fungal Pathogenesis, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, Korea
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Sugui JA, Kwon-Chung KJ, Juvvadi PR, Latgé JP, Steinbach WJ. Aspergillus fumigatus and related species. Cold Spring Harb Perspect Med 2014; 5:a019786. [PMID: 25377144 DOI: 10.1101/cshperspect.a019786] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The genus Aspergillus contains etiologic agents of aspergillosis. The clinical manifestations of the disease range from allergic reaction to invasive pulmonary infection. Among the pathogenic aspergilli, Aspergillus fumigatus is most ubiquitous in the environment and is the major cause of the disease, followed by Aspergillus flavus, Aspergillus niger, Aspergillus terreus, Aspergillus nidulans, and several species in the section Fumigati that morphologically resemble A. fumigatus. Patients that are at risk for acquiring aspergillosis are those with an altered immune system. Early diagnosis, species identification, and adequate antifungal therapy are key elements for treatment of the disease, especially in cases of pulmonary invasive aspergillosis that often advance very rapidly. Incorporating knowledge of the basic biology of Aspergillus species to that of the diseases that they cause is fundamental for further progress in the field.
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Affiliation(s)
- Janyce A Sugui
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Kyung J Kwon-Chung
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Praveen R Juvvadi
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University, Durham, North Carolina 27715
| | - Jean-Paul Latgé
- Unité des Aspergillus, Institut Pasteur, Paris 75724, France
| | - William J Steinbach
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University, Durham, North Carolina 27715 Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina 27710
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Abstract
Fungal pathogens must assimilate local nutrients to establish an infection in their mammalian host. We focus on carbon, nitrogen, and micronutrient assimilation mechanisms, discussing how these influence host-fungus interactions during infection. We highlight several emerging trends based on the available data. First, the perturbation of carbon, nitrogen, or micronutrient assimilation attenuates fungal pathogenicity. Second, the contrasting evolutionary pressures exerted on facultative versus obligatory pathogens have led to contemporary pathogenic fungal species that display differing degrees of metabolic flexibility. The evolutionarily ancient metabolic pathways are conserved in most fungal pathogen, but interesting gaps exist in some species (e.g., Candida glabrata). Third, metabolic flexibility is generally essential for fungal pathogenicity, and in particular, for the adaptation to contrasting host microenvironments such as the gastrointestinal tract, mucosal surfaces, bloodstream, and internal organs. Fourth, this metabolic flexibility relies on complex regulatory networks, some of which are conserved across lineages, whereas others have undergone significant evolutionary rewiring. Fifth, metabolic adaptation affects fungal susceptibility to antifungal drugs and also presents exciting opportunities for the development of novel therapies.
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Affiliation(s)
- Iuliana V Ene
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, 07745 Jena, Germany
| | - Alistair J P Brown
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, 07745 Jena, Germany Friedrich Schiller University, 07743 Jena, Germany Center for Sepsis Control and Care, Universitätsklinikum Jena, 07747 Jena, Germany
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Malavazi I, Goldman GH, Brown NA. The importance of connections between the cell wall integrity pathway and the unfolded protein response in filamentous fungi. Brief Funct Genomics 2014; 13:456-70. [PMID: 25060881 DOI: 10.1093/bfgp/elu027] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In the external environment, or within a host organism, filamentous fungi experience sudden changes in nutrient availability, osmolality, pH, temperature and the exposure to toxic compounds. The fungal cell wall represents the first line of defense, while also performing essential roles in morphology, development and virulence. A polarized secretion system is paramount for cell wall biosynthesis, filamentous growth, nutrient acquisition and interactions with the environment. The unique ability of filamentous fungi to secrete has resulted in their industrial adoption as fungal cell factories. Protein maturation and secretion commences in the endoplasmic reticulum (ER). The unfolded protein response (UPR) maintains ER functionality during exposure to secretion and cell wall stress. UPR, therefore, influences secretion and cell wall homeostasis, which in turn impacts upon numerous fungal traits important to pathogenesis and biotechnology. Subsequently, this review describes the relevance of the cell wall and UPR systems to filamentous fungal pathogens or industrial microbes and then highlights interconnections between the two systems. Ultimately, the possible biotechnological applications of an enhanced understanding of such regulatory systems in combating fungal disease, or the removal of natural bottlenecks in protein secretion in an industrial setting, are discussed.
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Guo L, Han L, Yang L, Zeng H, Fan D, Zhu Y, Feng Y, Wang G, Peng C, Jiang X, Zhou D, Ni P, Liang C, Liu L, Wang J, Mao C, Fang X, Peng M, Huang J. Genome and transcriptome analysis of the fungal pathogen Fusarium oxysporum f. sp. cubense causing banana vascular wilt disease. PLoS One 2014; 9:e95543. [PMID: 24743270 PMCID: PMC3990668 DOI: 10.1371/journal.pone.0095543] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 03/28/2014] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND The asexual fungus Fusarium oxysporum f. sp. cubense (Foc) causing vascular wilt disease is one of the most devastating pathogens of banana (Musa spp.). To understand the molecular underpinning of pathogenicity in Foc, the genomes and transcriptomes of two Foc isolates were sequenced. METHODOLOGY/PRINCIPAL FINDINGS Genome analysis revealed that the genome structures of race 1 and race 4 isolates were highly syntenic with those of F. oxysporum f. sp. lycopersici strain Fol4287. A large number of putative virulence associated genes were identified in both Foc genomes, including genes putatively involved in root attachment, cell degradation, detoxification of toxin, transport, secondary metabolites biosynthesis and signal transductions. Importantly, relative to the Foc race 1 isolate (Foc1), the Foc race 4 isolate (Foc4) has evolved with some expanded gene families of transporters and transcription factors for transport of toxins and nutrients that may facilitate its ability to adapt to host environments and contribute to pathogenicity to banana. Transcriptome analysis disclosed a significant difference in transcriptional responses between Foc1 and Foc4 at 48 h post inoculation to the banana 'Brazil' in comparison with the vegetative growth stage. Of particular note, more virulence-associated genes were up regulated in Foc4 than in Foc1. Several signaling pathways like the mitogen-activated protein kinase Fmk1 mediated invasion growth pathway, the FGA1-mediated G protein signaling pathway and a pathogenicity associated two-component system were activated in Foc4 rather than in Foc1. Together, these differences in gene content and transcription response between Foc1 and Foc4 might account for variation in their virulence during infection of the banana variety 'Brazil'. CONCLUSIONS/SIGNIFICANCE Foc genome sequences will facilitate us to identify pathogenicity mechanism involved in the banana vascular wilt disease development. These will thus advance us develop effective methods for managing the banana vascular wilt disease, including improvement of disease resistance in banana.
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Affiliation(s)
- Lijia Guo
- Key Laboratory of Monitoring and Control of Tropical Agricultural and Forest Invasive Alien Pests, Ministry of Agriculture, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | | | - Laying Yang
- Key Laboratory of Monitoring and Control of Tropical Agricultural and Forest Invasive Alien Pests, Ministry of Agriculture, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Huicai Zeng
- Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | | | | | | | - Guofen Wang
- Key Laboratory of Monitoring and Control of Tropical Agricultural and Forest Invasive Alien Pests, Ministry of Agriculture, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | | | | | | | | | - Changcong Liang
- Key Laboratory of Monitoring and Control of Tropical Agricultural and Forest Invasive Alien Pests, Ministry of Agriculture, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Lei Liu
- Key Laboratory of Monitoring and Control of Tropical Agricultural and Forest Invasive Alien Pests, Ministry of Agriculture, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Jun Wang
- Key Laboratory of Monitoring and Control of Tropical Agricultural and Forest Invasive Alien Pests, Ministry of Agriculture, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Chao Mao
- Key Laboratory of Monitoring and Control of Tropical Agricultural and Forest Invasive Alien Pests, Ministry of Agriculture, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | | | - Ming Peng
- Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Junsheng Huang
- Key Laboratory of Monitoring and Control of Tropical Agricultural and Forest Invasive Alien Pests, Ministry of Agriculture, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
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45
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Alshareef F, Robson GD. Genetic and virulence variation in an environmental population of the opportunistic pathogen Aspergillus fumigatus. MICROBIOLOGY-SGM 2014; 160:742-751. [PMID: 24464798 DOI: 10.1099/mic.0.072520-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Environmental populations of the opportunistic pathogen Aspergillus fumigatus have been shown to be genotypically diverse and to contain a range of isolates with varying pathogenic potential. In this study, we combined two RAPD primers to investigate the genetic diversity of environmental isolates from Manchester collected monthly over 1 year alongside Dublin environmental isolates and clinical isolates from patients. RAPD analysis revealed a diverse genotype, but with three major clinical isolate clusters. When the pathogenicity of clinical and Dublin isolates was compared with a random selection of Manchester isolates in a Galleria mellonella larvae model, as a group, clinical isolates were significantly more pathogenic than environmental isolates. Moreover, when relative pathogenicity of individual isolates was compared, clinical isolates were the most pathogenic, Dublin isolates were the least pathogenic and Manchester isolates showed a range in pathogenicity. Overall, this suggests that the environmental population is genetically diverse, displaying a range in pathogenicity, and that the most pathogenic strains from the environment are selected during patient infection.
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Affiliation(s)
- Fadwa Alshareef
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Manchester M16 8QW, UK
| | - Geoffrey D Robson
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Manchester M16 8QW, UK
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Dolezal AL, Obrian GR, Nielsen DM, Woloshuk CP, Boston RS, Payne GA. Localization, morphology and transcriptional profile of Aspergillus flavus during seed colonization. MOLECULAR PLANT PATHOLOGY 2013; 14:898-909. [PMID: 23834374 PMCID: PMC6638638 DOI: 10.1111/mpp.12056] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Aspergillus flavus is an opportunistic fungal pathogen that infects maize kernels pre-harvest, creating major human health concerns and causing substantial agricultural losses. Improved control strategies are needed, yet progress is hampered by the limited understanding of the mechanisms of infection. A series of studies were designed to investigate the localization, morphology and transcriptional profile of A. flavus during internal seed colonization. Results from these studies indicate that A. flavus is capable of infecting all tissues of the immature kernel by 96 h after infection. Mycelia were observed in and around the point of inoculation in the endosperm and were found growing down to the germ. At the endosperm-germ interface, hyphae appeared to differentiate and form a biofilm-like structure that surrounded the germ. The exact nature of this structure remains unclear, but is discussed. A custom-designed A. flavus Affymetrix GeneChip® microarray was used to monitor genome-wide transcription during pathogenicity. A total of 5061 genes were designated as being differentially expressed. Genes encoding secreted enzymes, transcription factors and secondary metabolite gene clusters were up-regulated and considered to be potential effector molecules responsible for disease in the kernel. Information gained from this study will aid in the development of strategies aimed at preventing or slowing down A. flavus colonization of the maize kernel.
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Affiliation(s)
- Andrea L Dolezal
- Department of Plant Pathology, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC, 27695, USA
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47
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López-Berges MS, Schäfer K, Hera C, Di Pietro A. Combinatorial function of velvet and AreA in transcriptional regulation of nitrate utilization and secondary metabolism. Fungal Genet Biol 2013; 62:78-84. [PMID: 24240057 DOI: 10.1016/j.fgb.2013.11.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 10/29/2013] [Accepted: 11/03/2013] [Indexed: 12/11/2022]
Abstract
Velvet is a conserved protein complex that functions as a regulator of fungal development and secondary metabolism. In the soil-inhabiting pathogen Fusarium oxysporum, velvet governs mycotoxin production and virulence on plant and mammalian hosts. Here we report a previously unrecognized role of the velvet complex in regulation of nitrate metabolism. F. oxysporum mutants lacking VeA or LaeA, two key components of the complex, were impaired in growth on the non-preferred nitrogen sources nitrate and nitrite. Both velvet and the general nitrogen response GATA factor AreA were required for transcriptional activation of nitrate (nit1) and nitrite (nii1) reductase genes under de-repressing conditions, as well as for the nitrate-triggered increase in chromatin accessibility at the nit1 locus. AreA also contributed to chromatin accessibility and expression of two velvet-regulated gene clusters, encoding biosynthesis of the mycotoxin beauvericin and of the siderophore ferricrocin. Thus, velvet and AreA coordinately orchestrate primary and secondary metabolism as well as virulence functions in F. oxysporum.
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Affiliation(s)
- Manuel S López-Berges
- Departamento de Genética, Facultad de Ciencias, Universidad de Córdoba, 14071 Córdoba, Spain; Campus de Excelencia Internacional Agroalimentario ceiA3, 14071 Córdoba, Spain
| | - Katja Schäfer
- Departamento de Genética, Facultad de Ciencias, Universidad de Córdoba, 14071 Córdoba, Spain; Campus de Excelencia Internacional Agroalimentario ceiA3, 14071 Córdoba, Spain
| | - Concepción Hera
- Departamento de Genética, Facultad de Ciencias, Universidad de Córdoba, 14071 Córdoba, Spain; Campus de Excelencia Internacional Agroalimentario ceiA3, 14071 Córdoba, Spain
| | - Antonio Di Pietro
- Departamento de Genética, Facultad de Ciencias, Universidad de Córdoba, 14071 Córdoba, Spain; Campus de Excelencia Internacional Agroalimentario ceiA3, 14071 Córdoba, Spain.
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Timpner C, Braus-Stromeyer SA, Tran VT, Braus GH. The Cpc1 regulator of the cross-pathway control of amino acid biosynthesis is required for pathogenicity of the vascular pathogen Verticillium longisporum. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:1312-1324. [PMID: 23883358 DOI: 10.1094/mpmi-06-13-0181-r] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The plant-pathogenic fungus Verticillium longisporum is a causal agent of early senescence and ripening in cruciferous crops like Brassica napus. Verticillium wilts have become serious agricultural threats in recent decades. Verticillium species infect host plants through the roots and colonize xylem vessels of the host plant. The xylem fluid provides an environment with limited carbon sources and unbalanced amino acid supply, which requires V. longisporum to induce the cross-pathway control of amino acid biosynthesis. RNA-mediated gene silencing reduced the expression of the two CPC1 isogenes (VlCPC1-1 and VlCPC1-2) of the allodiploid V. longisporum up to 85%. VlCPC1 encodes the conserved transcription factor of the cross-pathway control. The silenced mutants were highly sensitive to amino-acid starvation, and the infected plants showed significantly fewer symptoms such as stunting or early senescence in oilseed rape plant infection assays. Consistently, deletion of single CPC1 of the haploid V. dahliae resulted in strains that are sensitive to amino-acid starvation and cause strongly reduced symptoms in the plant-host tomato (Solanum lycopersicum). The allodiploid V. longisporum and the haploid V. dahliae are the first phytopathogenic fungi that were shown to require CPC1 for infection and colonization of their respective host plants, oilseed rape and tomato.
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Regulation of sulphur assimilation is essential for virulence and affects iron homeostasis of the human-pathogenic mould Aspergillus fumigatus. PLoS Pathog 2013; 9:e1003573. [PMID: 24009505 PMCID: PMC3757043 DOI: 10.1371/journal.ppat.1003573] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 07/08/2013] [Indexed: 11/19/2022] Open
Abstract
Sulphur is an essential element that all pathogens have to absorb from their surroundings in order to grow inside their infected host. Despite its importance, the relevance of sulphur assimilation in fungal virulence is largely unexplored. Here we report a role of the bZIP transcription factor MetR in sulphur assimilation and virulence of the human pathogen Aspergillus fumigatus. The MetR regulator is essential for growth on a variety of sulphur sources; remarkably, it is fundamental for assimilation of inorganic S-sources but dispensable for utilization of methionine. Accordingly, it strongly supports expression of genes directly related to inorganic sulphur assimilation but not of genes connected to methionine metabolism. On a broader scale, MetR orchestrates the comprehensive transcriptional adaptation to sulphur-starving conditions as demonstrated by digital gene expression analysis. Surprisingly, A. fumigatus is able to utilize volatile sulphur compounds produced by its methionine catabolism, a process that has not been described before and that is MetR-dependent. The A. fumigatus MetR transcriptional activator is important for virulence in both leukopenic mice and an alternative mini-host model of aspergillosis, as it was essential for the development of pulmonary aspergillosis and supported the systemic dissemination of the fungus. MetR action under sulphur-starving conditions is further required for proper iron regulation, which links regulation of sulphur metabolism to iron homeostasis and demonstrates an unprecedented regulatory crosstalk. Taken together, this study provides evidence that regulation of sulphur assimilation is not only crucial for A. fumigatus virulence but also affects the balance of iron in this prime opportunistic pathogen.
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The immune interplay between the host and the pathogen in Aspergillus fumigatus lung infection. BIOMED RESEARCH INTERNATIONAL 2013; 2013:693023. [PMID: 23984400 PMCID: PMC3745895 DOI: 10.1155/2013/693023] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 06/14/2013] [Indexed: 12/22/2022]
Abstract
The interplay between Aspergillus fumigatus and the host immune response in lung infection has been subject of studies over the last years due to its importance in immunocompromised patients. The multifactorial virulence factors of A. fumigatus are related to the fungus biological characteristics, for example, structure, ability to grow and adapt to high temperatures and stress conditions, besides capability of evading the immune system and causing damage to the host. In this context, the fungus recognition by the host innate immunity occurs when the pathogen disrupts the natural and chemical barriers followed by the activation of acquired immunity. It seems clear that a Th1 response has a protective role, whereas Th2 reactions are often associated with higher fungal burden, and Th17 response is still controversial. Furthermore, a fine regulation of the effector immunity is required to avoid excessive tissue damage associated with fungal clearance, and this role could be attributed to regulatory T cells. Finally, in this work we reviewed the aspects involved in the complex interplay between the host immune response and the pathogen virulence factors, highlighting the immunological issues and the importance of its better understanding to the development of novel therapeutic approaches for invasive lung aspergillosis.
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