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Böttcher B, Kienast SD, Leufken J, Eggers C, Sharma P, Leufken CM, Morgner B, Drexler HCA, Schulz D, Allert S, Jacobsen ID, Vylkova S, Leidel SA, Brunke S. A highly conserved tRNA modification contributes to C. albicans filamentation and virulence. Microbiol Spectr 2024; 12:e0425522. [PMID: 38587411 PMCID: PMC11064501 DOI: 10.1128/spectrum.04255-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 01/18/2024] [Indexed: 04/09/2024] Open
Abstract
tRNA modifications play important roles in maintaining translation accuracy in all domains of life. Disruptions in the tRNA modification machinery, especially of the anticodon stem loop, can be lethal for many bacteria and lead to a broad range of phenotypes in baker's yeast. Very little is known about the function of tRNA modifications in host-pathogen interactions, where rapidly changing environments and stresses require fast adaptations. We found that two closely related fungal pathogens of humans, the highly pathogenic Candida albicans and its much less pathogenic sister species, Candida dubliniensis, differ in the function of a tRNA-modifying enzyme. This enzyme, Hma1, exhibits species-specific effects on the ability of the two fungi to grow in the hypha morphology, which is central to their virulence potential. We show that Hma1 has tRNA-threonylcarbamoyladenosine dehydratase activity, and its deletion alters ribosome occupancy, especially at 37°C-the body temperature of the human host. A C. albicans HMA1 deletion mutant also shows defects in adhesion to and invasion into human epithelial cells and shows reduced virulence in a fungal infection model. This links tRNA modifications to host-induced filamentation and virulence of one of the most important fungal pathogens of humans.IMPORTANCEFungal infections are on the rise worldwide, and their global burden on human life and health is frequently underestimated. Among them, the human commensal and opportunistic pathogen, Candida albicans, is one of the major causative agents of severe infections. Its virulence is closely linked to its ability to change morphologies from yeasts to hyphae. Here, this ability is linked-to our knowledge for the first time-to modifications of tRNA and translational efficiency. One tRNA-modifying enzyme, Hma1, plays a specific role in C. albicans and its ability to invade the host. This adds a so-far unknown layer of regulation to the fungal virulence program and offers new potential therapeutic targets to fight fungal infections.
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Affiliation(s)
- Bettina Böttcher
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Sandra D. Kienast
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Johannes Leufken
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Cristian Eggers
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Puneet Sharma
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Christine M. Leufken
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Bianka Morgner
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Hannes C. A. Drexler
- Bioanalytical Mass Spectrometry Unit, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Daniela Schulz
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Stefanie Allert
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Ilse D. Jacobsen
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Slavena Vylkova
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Sebastian A. Leidel
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
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Wu H, Wang L, Wang W, Shao Z, Jia X, Xiao H, Chen J. The secretory Candida effector Sce1 licenses fungal virulence by masking the immunogenic β-1,3-glucan and promoting apoptosis of the host cells. MLIFE 2023; 2:159-177. [PMID: 38817625 PMCID: PMC10989805 DOI: 10.1002/mlf2.12066] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 03/28/2023] [Accepted: 04/05/2023] [Indexed: 06/01/2024]
Abstract
Candida albicans deploys a variety of mechanisms such as morphological switch and elicitor release to promote virulence. However, the intricate interactions between the fungus and the host remain poorly understood, and a comprehensive inventory of fungal virulence factors has yet to be established. In this study, we identified a C. albicans secretory effector protein Sce1, whose induction and secretion are associated with vagina-simulative conditions and chlamydospore formation. Sequence alignment showed that Sce1 belongs to a Pir family in C. albicans, which is conserved across several fungi and primarily characterized as a β-glucan binding protein in the Saccharomyces cerevisiae. Mechanically, Sce1 is primarily localized to the cell wall in a cleaved form as an alkali-labile β-1,3-glucan binding protein and plays a role in masking β-glucan in acidic environments and chlamydospores, a feature that might underline C. albicans' ability to evade host immunity. Further, a cleaved short form of Sce1 protein could be released into extracellular compartments and presented in bone marrow-derived macrophages infected with chlamydospores. This cleaved short form of Sce1 also demonstrated a unique ability to trigger the caspases-8/9-dependent apoptosis in various host cells. Correspondingly, genetic deletion of SCE1 led to dampened vaginal colonization of C. albicans and diminished fungal virulence during systemic infection. The discovery of Sce1 as a versatile virulence effector that executes at various compartments sheds light on the fungus-host interactions and C. albicans pathogenesis.
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Affiliation(s)
- Hongyu Wu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Li Wang
- The Center for Microbes, Development and Health, Institut Pasteur of Shanghai, Chinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
- Clinical Medicine Scientific and Technical Innovation Center, Shanghai Tenth People's HospitalTongji University School of MedicineShanghaiChina
| | - Wenjuan Wang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Zhugui Shao
- The Center for Microbes, Development and Health, Institut Pasteur of Shanghai, Chinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
- Key Laboratory of Infection and Immunity of Shandong Province and Department of Immunology, School of Biomedical SciencesShandong UniversityJinanChina
| | - Xin‐Ming Jia
- Clinical Medicine Scientific and Technical Innovation Center, Shanghai Tenth People's HospitalTongji University School of MedicineShanghaiChina
| | - Hui Xiao
- The Center for Microbes, Development and Health, Institut Pasteur of Shanghai, Chinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Jiangye Chen
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
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3
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Kakade P, Sircaik S, Maufrais C, Ene IV, Bennett RJ. Aneuploidy and gene dosage regulate filamentation and host colonization by Candida albicans. Proc Natl Acad Sci U S A 2023; 120:e2218163120. [PMID: 36893271 PMCID: PMC10089209 DOI: 10.1073/pnas.2218163120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 02/02/2023] [Indexed: 03/11/2023] Open
Abstract
Aneuploidy is a frequent occurrence in fungal species where it can alter gene expression and promote adaptation to a variety of environmental cues. Multiple forms of aneuploidy have been observed in the opportunistic fungal pathogen Candida albicans, which is a common component of the human gut mycobiome but can escape this niche and cause life-threatening systemic disease. Using a barcode sequencing (Bar-seq) approach, we evaluated a set of diploid C. albicans strains and found that a strain carrying a third copy of chromosome (Chr) 7 was associated with increased fitness during both gastrointestinal (GI) colonization and systemic infection. Our analysis revealed that the presence of a Chr 7 trisomy resulted in decreased filamentation, both in vitro and during GI colonization, relative to isogenic euploid controls. A target gene approach demonstrated that NRG1, encoding a negative regulator of filamentation located on Chr 7, contributes to increased fitness of the aneuploid strain due to inhibition of filamentation in a gene dosage-dependent fashion. Together, these experiments establish how aneuploidy enables the reversible adaptation of C. albicans to its host via gene dosage-dependent regulation of morphology.
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Affiliation(s)
- Pallavi Kakade
- Molecular Microbiology and Immunology Department, Brown University, Providence, RI02912
| | - Shabnam Sircaik
- Molecular Microbiology and Immunology Department, Brown University, Providence, RI02912
| | - Corinne Maufrais
- Institut Pasteur Bioinformatic Hub, Université Paris Cité, Paris75015, France
- Institut Pasteur, Université Paris Cité, Fungal Heterogeneity Lab, Paris75015, France
| | - Iuliana V. Ene
- Institut Pasteur, Université Paris Cité, Fungal Heterogeneity Lab, Paris75015, France
| | - Richard J. Bennett
- Molecular Microbiology and Immunology Department, Brown University, Providence, RI02912
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Karuppiah V, Zhang C, Liu T, Li Y, Chen J. Transcriptome Analysis of T. asperellum GDFS 1009 Revealed the Role of MUP1 Gene on the Methionine-Based Induction of Morphogenesis and Biological Control Activity. J Fungi (Basel) 2023; 9:jof9020215. [PMID: 36836329 PMCID: PMC9963050 DOI: 10.3390/jof9020215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/25/2023] [Accepted: 01/31/2023] [Indexed: 02/10/2023] Open
Abstract
Trichoderma spp. are biological control agents extensively used against various plant pathogens. However, the key genes shared for the growth, development and biological activity are unclear. In this study, we explored the genes responsible for the growth and development of T. asperellum GDFS 1009 under liquid-shaking culture compared to solid-surface culture. Transcriptome analysis revealed 2744 differentially expressed genes, and RT-qPCR validation showed that the high-affinity methionine permease MUP1 was the key gene for growth under different media. Deletion of the MUP1 inhibited the transport of amino acids, especially methionine, thereby inhibiting mycelial growth and sporulation, whereas inhibition could be mitigated by adding methionine metabolites such as SAM, spermidine and spermine. The MUP1 gene responsible for the methionine-dependent growth of T. asperellum was confirmed to be promoted through the PKA pathway but not the MAPK pathway. Furthermore, the MUP1 gene also increased the mycoparasitic activity of T. asperellum against Fusarium graminearum. Greenhouse experiments revealed that MUP1 strengthens the Trichoderma-induced crop growth promotion effect and SA-induced pathogen defense potential in maize. Our study highlights the effect of the MUP1 gene on growth and morphological differentiation and its importance for the agricultural application of Trichoderma against plant diseases.
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Affiliation(s)
- Valliappan Karuppiah
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
- State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Cheng Zhang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
- State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tong Liu
- Key Laboratory of Genetics and Germplasm Innovation of Tropical Special Forest Trees and Ornamental Plants, Ministry of Education, Hainan University, Haikou 570228, China
| | - Yi Li
- Shanghai Dajing Biotec. Ltd., Shanghai 201100, China
| | - Jie Chen
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
- State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China
- Correspondence:
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Humicolopsis cephalosporioides synthesizes DHN-melanin in its chlamydospores. Mycol Prog 2023. [DOI: 10.1007/s11557-022-01853-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Kim J, Oh SH, Rodriguez-Bobadilla R, Vuong VM, Hubka V, Zhao X, Hoyer LL. Peering Into Candida albicans Pir Protein Function and Comparative Genomics of the Pir Family. Front Cell Infect Microbiol 2022; 12:836632. [PMID: 35372132 PMCID: PMC8975586 DOI: 10.3389/fcimb.2022.836632] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/11/2022] [Indexed: 11/24/2022] Open
Abstract
The fungal cell wall, comprised primarily of protein and polymeric carbohydrate, maintains cell structure, provides protection from the environment, and is an important antifungal drug target. Pir proteins (proteins with internal repeats) are linked to cell wall β-1,3-glucan and are best studied in Saccharomyces cerevisiae. Sequential deletion of S. cerevisiae PIR genes produces strains with increasingly notable cell wall damage. However, a true null mutant lacking all five S. cerevisiae PIR genes was never constructed. Because only two PIR genes (PIR1, PIR32) were annotated in the Candida albicans genome, the initial goal of this work was to construct a true Δpir/Δpir null strain in this species. Unexpectedly, the phenotype of the null strain was almost indistinguishable from its parent, leading to the search for other proteins with Pir function. Bioinformatic approaches revealed nine additional C. albicans proteins that share a conserved Pir functional motif (minimally DGQ). Examination of the protein sequences revealed another conserved motif (QFQFD) toward the C-terminal end of each protein. Sequence similarities and presence of the conserved motif(s) were used to identify a set of 75 proteins across 16 fungal species that are proposed here as Pir proteins. The Pir family is greatly expanded in C. albicans and C. dubliniensis compared to other species and the orthologs are known to have specialized function during chlamydospore formation. Predicted Pir structures showed a conserved core of antiparallel beta-sheets and sometimes-extensive loops that contain amino acids with the potential to form linkages to cell wall components. Pir phylogeny demonstrated emergence of specific ortholog groups among the fungal species. Variation in gene expression patterns was noted among the ortholog groups during growth in rich medium. PIR allelic variation was quite limited despite the presence of a repeated sequence in many loci. Results presented here demonstrate that the Pir family is larger than previously recognized and lead to new hypotheses to test to better understand Pir proteins and their role in the fungal cell wall.
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Affiliation(s)
- Jisoo Kim
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Soon-Hwan Oh
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | | | - Vien M. Vuong
- Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Vit Hubka
- Department of Botany, Faculty of Science, Charles University, Prague, Czechia
- Laboratory of Fungal Genetics and Metabolism, Institute of Microbiology, Czech Academy of Sciences, Prague, Czechia
| | - Xiaomin Zhao
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Lois L. Hoyer
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- *Correspondence: Lois L. Hoyer,
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Peng X, Wu B, Zhang S, Li M, Jiang X. Transcriptome Dynamics Underlying Chlamydospore Formation in Trichoderma virens GV29-8. Front Microbiol 2021; 12:654855. [PMID: 34168625 PMCID: PMC8217873 DOI: 10.3389/fmicb.2021.654855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 05/03/2021] [Indexed: 11/15/2022] Open
Abstract
Trichoderma spp. are widely used biocontrol agents which are antagonistic to a variety of plant pathogens. Chlamydospores are a type of propagules produced by many fungi that have thick walls and are highly resistant to adverse environmental conditions. Chlamydospore preparations of Trichoderma spp. can withstand various storage conditions, have a longer shelf life than conidial preparations and have better application potential. However, large-scale production of chlamydospores has proven difficult. To understand the molecular mechanisms governing chlamydospore formation (CF) in Trichoderma fungi, we performed a comprehensive analysis of transcriptome dynamics during CF across 8 different developmental time points, which were divided into 4 stages according to PCA analysis: the mycelium growth stage (S1), early and middle stage of CF (S2), flourishing stage of CF (S3), and late stage of CF and mycelia initial autolysis (S4). 2864, 3206, and 3630 DEGs were screened from S2 vs S1, S3 vs S2, and S4 vs S3, respectively. We then identified the pathways and genes that play important roles in each stage of CF by GO, KEGG, STC and WGCNA analysis. The results showed that DEGs in the S2 vs S1 were mainly enriched in organonitrogen compound metabolism, those in S3 vs S2 were mainly involved in secondary metabolite, cell cycle, and N-glycan biosynthesis, and DEGs in S4 vs S3 were mainly involved in lipid, glycogen, and chitin metabolic processes. We speculated that mycelial assimilation and absorption of exogenous nitrogen in the early growth stage (S1), resulted in subsequent nitrogen deficiency (S2). At the same time, secondary metabolites and active oxygen free radicals released during mycelial growth produced an adverse growth environment. The resulting nitrogen-deficient and toxin enriched medium may stimulate cell differentiation by initiating cell cycle regulation to induce morphological transformation of mycelia into chlamydospores. High expression of genes relating to glycogen, lipid, mannan, and chitin synthetic metabolic pathways during the flourishing (S3) and late stages (S4) of CF may be conducive to energy storage and cell wall construction in chlamydospores. For further verifying the functions of the amino sugar and nucleotide sugar metabolism (tre00520) pathway in the CF of T. virens GV29-8 strain, the chitin synthase gene (TRIVIDRAFT_90152), one key gene of the pathway, was deleted and resulted in the dysplasia of mycelia and an incapability to form normal chlamydospores, which illustrated the pathway affecting the CF of T. virens GV29-8 strain. Our results provide a new perspective for understanding the genetics of biochemical pathways involved in CF of Trichoderma spp.
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Affiliation(s)
| | | | | | - Mei Li
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiliang Jiang
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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A Conserved Machinery Underlies the Synthesis of a Chitosan Layer in the Candida Chlamydospore Cell Wall. mSphere 2021; 6:6/2/e00080-21. [PMID: 33910989 PMCID: PMC8092133 DOI: 10.1128/msphere.00080-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The polysaccharide chitosan is found in the cell wall of specific cell types in a variety of fungal species where it contributes to stress resistance, or in pathogenic fungi, virulence. Under certain growth conditions, the pathogenic yeast Candida dubliniensis forms a cell type termed a chlamydospore, which has an additional internal layer in its cell wall compared to hyphal or yeast cell types. We report that this internal layer of the chlamydospore wall is rich in chitosan. The ascospore wall of Saccharomyces cerevisiae also has a distinct chitosan layer. As in S. cerevisiae, formation of the chitosan layer in the C. dubliniensis wall requires the chitin synthase CHS3 and the chitin deacetylase CDA2 In addition, three lipid droplet-localized proteins-Rrt8, Srt1, and Mum3-identified in S. cerevisiae as important for chitosan layer assembly in the ascospore wall are required for the formation of the chitosan layer of the chlamydospore wall in C. dubliniensis These results reveal that a conserved machinery is required for the synthesis of a distinct chitosan layer in the walls of these two yeasts and may be generally important for incorporation of chitosan into fungal walls.IMPORTANCE The cell wall is the interface between the fungal cell and its environment and disruption of cell wall assembly is an effective strategy for antifungal therapies. Therefore, a detailed understanding of how cell walls form is critical to identify potential drug targets and develop therapeutic strategies. This study shows that a set of genes required for the assembly of a chitosan layer in the cell wall of S. cerevisiae is also necessary for chitosan formation in a different cell type in a different yeast, C. dubliniensis Because chitosan incorporation into the cell wall can be important for virulence, the conservation of this pathway suggests possible new targets for antifungals aimed at disrupting cell wall function.
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Abstract
Of the many microbial species on earth, only a small number are able to thrive in humans and cause disease. Comparison of closely related pathogenic and nonpathogenic species can therefore be useful in identifying key features that contribute to virulence. We created interspecies hybrids between Candida albicans, a prevalent fungal pathogen of humans, and Candida dubliniensis, a close, but much less pathogenic, relative. By comparing genome-wide expression differences between the two genomes in the same cell, we surmised that since the two species diverged from a common ancestor, natural selection has acted upon the expression level of an ancient metabolic pathway, illustrating that pathogenicity traits can arise over evolutionary timescales through small expression changes in deeply conserved proteins. Candida albicans is the most common cause of systemic fungal infections in humans and is considerably more virulent than its closest known relative, Candida dubliniensis. To investigate this difference, we constructed interspecies hybrids and quantified mRNA levels produced from each genome in the hybrid. This approach systematically identified expression differences in orthologous genes arising from cis-regulatory sequence changes that accumulated since the two species last shared a common ancestor, some 10 million y ago. We documented many orthologous gene-expression differences between the two species, and we pursued one striking observation: All 15 genes coding for the enzymes of glycolysis showed higher expression from the C. albicans genome than the C. dubliniensis genome in the interspecies hybrid. This pattern requires evolutionary changes to have occurred at each gene; the fact that they all act in the same direction strongly indicates lineage-specific natural selection as the underlying cause. To test whether these expression differences contribute to virulence, we created a C. dubliniensis strain in which all 15 glycolysis genes were produced at modestly elevated levels and found that this strain had significantly increased virulence in the standard mouse model of systemic infection. These results indicate that small expression differences across a deeply conserved set of metabolism enzymes can play a significant role in the evolution of virulence in fungal pathogens.
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A conserved regulator controls asexual sporulation in the fungal pathogen Candida albicans. Nat Commun 2020; 11:6224. [PMID: 33277479 PMCID: PMC7718266 DOI: 10.1038/s41467-020-20010-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 11/03/2020] [Indexed: 12/16/2022] Open
Abstract
Transcription factor Rme1 is conserved among ascomycetes and regulates meiosis and pseudohyphal growth in Saccharomyces cerevisiae. The genome of the meiosis-defective pathogen Candida albicans encodes an Rme1 homolog that is part of a transcriptional circuitry controlling hyphal growth. Here, we use chromatin immunoprecipitation and genome-wide expression analyses to study a possible role of Rme1 in C. albicans morphogenesis. We find that Rme1 binds upstream and activates the expression of genes that are upregulated during chlamydosporulation, an asexual process leading to formation of large, spherical, thick-walled cells during nutrient starvation. RME1 deletion abolishes chlamydosporulation in three Candida species, whereas its overexpression bypasses the requirement for chlamydosporulation cues and regulators. RME1 expression levels correlate with chlamydosporulation efficiency across clinical isolates. Interestingly, RME1 displays a biphasic pattern of expression, with a first phase independent of Rme1 function and dependent on chlamydospore-inducing cues, and a second phase dependent on Rme1 function and independent of chlamydospore-inducing cues. Our results indicate that Rme1 plays a central role in chlamydospore development in Candida species.
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Correia I, Wilson D, Hube B, Pla J. Characterization of a Candida albicans Mutant Defective in All MAPKs Highlights the Major Role of Hog1 in the MAPK Signaling Network. J Fungi (Basel) 2020; 6:jof6040230. [PMID: 33080787 PMCID: PMC7711971 DOI: 10.3390/jof6040230] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/12/2020] [Accepted: 10/14/2020] [Indexed: 12/16/2022] Open
Abstract
The success of Candida albicans as a pathogen relies on its ability to adapt and proliferate in different environmental niches. Pathways regulated by mitogen-activated protein kinases (MAPKs) are involved in sensing environmental conditions and developing an accurate adaptive response. Given the frequent cooperative roles of these routes in cellular functions, we have generated mutants defective in all combinations of the four described MAPKs in C. albicans and characterized its phenotype regarding sensitiveness to specific drugs, morphogenesis and interaction with host immune cells. We demonstrate that all MAPKs are dispensable in this yeast as a mutant defective in Cek1, Cek2, Mkc1 and Hog1 is viable although highly sensitive to oxidative and osmotic stress, displaying a specific pattern of sensitivity to antifungals. By comparing its phenotype with single, double and triple combinations of MAPK-deletion mutants we were able to unveil a Cek1-independent mechanism for Hog1 resistance to Congo red, and confirm the predominant effect of Hog1 on oxidative and osmotic adaptation. The quadruple mutant produces filaments under non-inducing conditions, but is unable to develop chlamydospores. Furthermore, cek1 cek2 mkc1 hog1 cells switch to the opaque state at high frequency, which is blocked by the ectopic expression of HOG1 suggesting a role of this kinase for phenotypic switching.
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Affiliation(s)
- Inês Correia
- iBiMED-Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Agra do Crasto, 3810-193 Aveiro, Portugal
- Correspondence: (I.C.); (J.P.); Tel.: +351-234-370-213 (I.C.); +34-913-941-617 (J.P.)
| | - Duncan Wilson
- Medical Research Council Centre for Medical Mycology, School of Biosciences, University of Exeter, Exeter EX4 4QD, UK;
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans-Knoell-Institute, Beutenbergstraße 11A, 07745 Jena, Germany;
- Institute of Microbiology, Friedrich Schiller University, Neugasse 25, 07743 Jena, Germany
| | - Jesús Pla
- Departamento de Microbiología y Parasitología-IRYCIS, Facultad de Farmacia, Universidad Complutense de Madrid, Avda. Ramón y Cajal s/n, 28040 Madrid, Spain
- Correspondence: (I.C.); (J.P.); Tel.: +351-234-370-213 (I.C.); +34-913-941-617 (J.P.)
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Dawson CS, Garcia-Ceron D, Rajapaksha H, Faou P, Bleackley MR, Anderson MA. Protein markers for Candida albicans EVs include claudin-like Sur7 family proteins. J Extracell Vesicles 2020; 9:1750810. [PMID: 32363014 PMCID: PMC7178836 DOI: 10.1080/20013078.2020.1750810] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 03/24/2020] [Accepted: 03/27/2020] [Indexed: 01/09/2023] Open
Abstract
Background: Fungal extracellular vesicles (EVs) have been implicated in host-pathogen and pathogen-pathogen communication in some fungal diseases. In depth research into fungal EVs has been hindered by the lack of specific protein markers such as those found in mammalian EVs that have enabled sophisticated isolation and analysis techniques. Despite their role in fungal EV biogenesis, ESCRT proteins such as Vps23 (Tsg101) and Bro1 (ALIX) are not present as fungal EV cargo. Furthermore, tetraspanin homologs are yet to be identified in many fungi including the model yeast S. cerevisiae. Objective: We performed de novo identification of EV protein markers for the major human fungal pathogen Candida albicans with adherence to MISEV2018 guidelines. Materials and methods: EVs were isolated by differential ultracentrifugation from DAY286, ATCC90028 and ATCC10231 yeast cells, as well as DAY286 biofilms. Whole cell lysates (WCL) were also obtained from the EV-releasing cells. Label-free quantitative proteomics was performed to determine the set of proteins consistently enriched in EVs compared to WCL. Results: 47 proteins were consistently enriched in C. albicans EVs. We refined these to 22 putative C. albicans EV protein markers including the claudin-like Sur7 family (Pfam: PF06687) proteins Sur7 and Evp1 (orf19.6741). A complementary set of 62 EV depleted proteins was selected as potential negative markers. Conclusions: The marker proteins for C. albicans EVs identified in this study will be useful tools for studies on EV biogenesis and cargo loading in C. albicans and potentially other fungal species and will also assist in elucidating the role of EVs in C. albicans pathogenesis. Many of the proteins identified as putative markers are fungal specific proteins indicating that the pathways of EV biogenesis and cargo loading may be specific to fungi, and that assumptions made based on studies in mammalian cells could be misleading. Abbreviations: A1 - ATCC10231; A9 - ATCC90028; DAY B - DAY286 biofilm; DAY Y - DAY286 yeast; EV - extracellular vesicle; Evp1 - extracellular vesicle protein 1 (orf19.6741); GO - gene ontology; Log2(FC) - log2(fold change); MCC - membrane compartment of Can1; MDS - multidimensional scaling; MISEV - minimal information for studies of EVs; sEVs - small EVs; SP - signal peptide; TEMs - tetraspanin enriched microdomains; TM - transmembrane; VDM - vesicle-depleted medium; WCL - whole cell lysate.
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Affiliation(s)
- Charlotte S Dawson
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science. La Trobe University, Australia
- Department of Biochemistry, Cambridge Centre for Proteomics, Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge, UK
| | - Donovan Garcia-Ceron
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science. La Trobe University, Australia
| | - Harinda Rajapaksha
- La Trobe Comprehensive Proteomics Platform, La Trobe Institute for Molecular Science. La Trobe University, Australia
| | - Pierre Faou
- La Trobe Comprehensive Proteomics Platform, La Trobe Institute for Molecular Science. La Trobe University, Australia
| | - Mark R Bleackley
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science. La Trobe University, Australia
| | - Marilyn A Anderson
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science. La Trobe University, Australia
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Cottier F, Hall RA. Face/Off: The Interchangeable Side of Candida Albicans. Front Cell Infect Microbiol 2020; 9:471. [PMID: 32047726 PMCID: PMC6997470 DOI: 10.3389/fcimb.2019.00471] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/20/2019] [Indexed: 12/20/2022] Open
Abstract
Due to limited mobility, fungi, like most unicellular organisms, have evolved mechanisms to adapt to sudden chemical and/or physical variation in their environment. Candida albicans is recognized as a model organism to study eukaryotic responses to environmental changes, as this human commensal yeast but also opportunistic pathogen responds to numerous environmental cues through switching morphologies from yeast to hyphae growth. This mechanism is largely controlled by two major pathways: cAMP-PKA and MAPK, but each environmental signal is sensed by specific sensors. However, morphological switching is not the only response C. albicans exerts in response to environmental cues. Recently, fungal cell wall remodeling in response to host-derived environmental cues has been identified as a way for C. albicans to manipulate the innate immune system. The fungal cell wall is composed of a chitin skeleton linked to a network of β-glucan, which anchors proteins and mannans to the fungal cell surface. As localized on the cell surface, these molecules drive interactions with the environment and other cells, particularly with host immune cells. C. albicans is recognized by immune cells such as neutrophils and macrophages via pathogen recognition receptors (PRRs) that bind different components of the cell wall. While β-glucan and mannan are proinflammatory molecules, chitin can induce anti-inflammatory responses. Interestingly, C. albicans is able to regulate the exposure of these pathogen-associated molecular patterns (PAMPs) according to environmental cues resulting in a modulation of the host immune response. This review describes the mechanisms involved in C. albicans response to environmental changes and their effect on immune recognition.
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Affiliation(s)
- Fabien Cottier
- School of Biosciences, Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Rebecca A Hall
- School of Biosciences, Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom.,Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, United Kingdom
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14
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Whole RNA-sequencing and gene expression analysis of Trichoderma harzianum Tr-92 under chlamydospore-producing condition. Genes Genomics 2019; 41:689-699. [PMID: 30968334 DOI: 10.1007/s13258-019-00812-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 03/21/2019] [Indexed: 12/31/2022]
Abstract
BACKGROUND Trichoderma is one of the most important biocontrol fungi, which could produce mycelia, conidiospores, and chlamydospores three types of propagules under different conditions. Chlamydospores are produced in harsh conditions in various fungi, and may be more resistant to adverse conditions. However, the knowledge associated with the mechanism of chlamydospore formation remained unclear in Trichoderma. OBJECTIVES This study is aimed to explore the essential genes and regulatory pathways associated with chlamydospore formation in Trichoderma. METHODS The culture condition, survival rate, and biocontrol effects of chlamydospores and conidiospores from Trichoderma.harzianum Tr-92 were determined. Furthermore, the whole transcriptome profiles of T. harzianum Tr-92 under chlamydospore-producing and chlamydospore-nonproducing conditions were performed. RESULTS T. harzianum Tr-92 produced chlamydospores under particular conditions, and chlamydospore-based formulation of T. harzianum Tr-92 exhibited higher biocontrol ability against Botrytis cinerea in cucumber than conidoiospore-based formulation. In the transcriptome analysis, a total of 2,029 differentially expressed genes (DEGs) were identified in T. harzianum Tr-92 under chlamydospore-producing condition, compared to that under chlamydospore-nonproducing condition. GO classification indicated that the DEGs were significantly enriched in 284 terms among biological process, cellular components and molecular function categories. A total of 19 pathways were observed with DEGs by KEGG analysis. Furthermore, fifteen DEGs were verified by quantitative real-time PCR, and the expression profiles were consistent with the transcriptome data. CONCLUSION The results would provide a basis on the molecular mechanisms underlying Trichoderma sporulation, which would assist the development and application of fungal biocontrol agents.
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Sun ZB, Zhang J, Sun MH, Li SD. Identification of genes related to chlamydospore formation in Clonostachys rosea 67-1. Microbiologyopen 2018; 8:e00624. [PMID: 29635882 PMCID: PMC6341034 DOI: 10.1002/mbo3.624] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 02/11/2018] [Accepted: 02/16/2018] [Indexed: 01/15/2023] Open
Abstract
Chlamydospores are specific structures that are of great significance to the commercialization of fungal biopesticides. To explore the genes associated with chlamydospore formation, a biocontrol fungus Clonostachys rosea 67‐1 that is capable of producing resistant spores under particular conditions was investigated by transcriptome sequencing and analysis. A total of 549,661,174 clean reads were obtained, and a series of differentially expressed genes potentially involved in fungal chlamydospore formation were identified. At 36 hr, 67 and 117 genes were up‐ and downregulated in C. rosea during chlamydospore production, compared with the control for conidiation, and 53 and 24 genes were up‐ and downregulated at 72 hr. GO classification suggested that the differentially expressed genes were related to cellular component, biological process, and molecular function categories. A total of 188 metabolism pathways were linked to chlamydospore production by KEGG analysis. Sixteen differentially expressed genes were verified by reverse transcription quantitative PCR, and the expression profiles were consistent with the transcriptome data. To the best of our knowledge, it is the first report on the genes associated with chlamydospore formation in C. rosea. The results provide insight into the molecular mechanisms underlying C. rosea sporulation, which will assist the development of fungal biocontrol agents.
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Affiliation(s)
- Zhan-Bin Sun
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jun Zhang
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Man-Hong Sun
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shi-Dong Li
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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16
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Giosa D, Felice MR, Lawrence TJ, Gulati M, Scordino F, Giuffrè L, Lo Passo C, D'Alessandro E, Criseo G, Ardell DH, Hernday AD, Nobile CJ, Romeo O. Whole RNA-Sequencing and Transcriptome Assembly of Candida albicans and Candida africana under Chlamydospore-Inducing Conditions. Genome Biol Evol 2017; 9:1971-1977. [PMID: 28810711 PMCID: PMC5553385 DOI: 10.1093/gbe/evx143] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2017] [Indexed: 12/27/2022] Open
Abstract
Candida albicans is the most common cause of life-threatening fungal infections in humans, especially in immunocompromised individuals. Crucial to its success as an opportunistic pathogen is the considerable dynamism of its genome, which readily undergoes genetic changes generating new phenotypes and shaping the evolution of new strains. Candida africana is an intriguing C. albicans biovariant strain that exhibits remarkable genetic and phenotypic differences when compared with standard C. albicans isolates. Candida africana is well-known for its low degree of virulence compared with C. albicans and for its inability to produce chlamydospores that C. albicans, characteristically, produces under certain environmental conditions. Chlamydospores are large, spherical structures, whose biological function is still unknown. For this reason, we have sequenced, assembled, and annotated the whole transcriptomes obtained from an efficient C. albicans chlamydospore-producing clinical strain (GE1), compared with the natural chlamydospore-negative C. africana clinical strain (CBS 11016). The transcriptomes of both C. albicans (GE1) and C. africana (CBS 11016) clinical strains, grown under chlamydospore-inducing conditions, were sequenced and assembled into 7,442 (GE1 strain) and 8,370 (CBS 11016 strain) high quality transcripts, respectively. The release of the first assembly of the C. africana transcriptome will allow future comparative studies to better understand the biology and evolution of this important human fungal pathogen.
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Affiliation(s)
| | - Maria Rosa Felice
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, Italy
| | - Travis J Lawrence
- Department of Molecular and Cell Biology, University of California, Merced, CA.,Quantitative and System Biology Graduate Program, University of California, Merced, CA
| | - Megha Gulati
- Department of Molecular and Cell Biology, University of California, Merced, CA
| | | | - Letterio Giuffrè
- Department of Veterinary Sciences, Division of Animal Production, University of Messina, Italy
| | - Carla Lo Passo
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, Italy
| | - Enrico D'Alessandro
- Department of Veterinary Sciences, Division of Animal Production, University of Messina, Italy
| | - Giuseppe Criseo
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, Italy
| | - David H Ardell
- Department of Molecular and Cell Biology, University of California, Merced, CA
| | - Aaron D Hernday
- Department of Molecular and Cell Biology, University of California, Merced, CA
| | - Clarissa J Nobile
- Department of Molecular and Cell Biology, University of California, Merced, CA
| | - Orazio Romeo
- IRCCS Centro Neurolesi "Bonino-Pulejo," Messina, Italy.,Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, Italy
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18
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Böttcher B, Pöllath C, Staib P, Hube B, Brunke S. Candida species Rewired Hyphae Developmental Programs for Chlamydospore Formation. Front Microbiol 2016; 7:1697. [PMID: 27833594 PMCID: PMC5081361 DOI: 10.3389/fmicb.2016.01697] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/12/2016] [Indexed: 01/14/2023] Open
Abstract
Chlamydospore formation is a characteristic of many fungal species, among them the closely related human-pathogenic dimorphic yeasts Candida albicans and C. dubliniensis. Whereas function and regulation of filamentation are well-studied in these species, the basis of chlamydospore formation is mostly unknown. Here, we investigate the contribution of environmental and genetic factors and identified central proteins involved in species-specific regulation of chlamydosporulation. We show that specific nutrient levels strongly impact chlamydospore initiation, with starvation favoring sporulation and elevated levels of saccharides or peptone inhibiting it. Thresholds for these nutritional effects differ between C. albicans and C. dubliniensis, which explain species-specific chlamydospore formation on certain diagnostic media. A C. albicans nrg1Δ mutant phenocopied C. dubliniensis, putting Nrg1 regulation at the basis of species-specific chlamydospore formation under various conditions. By screening a series of potential chlamydospore regulators, we identified the TOR and cAMP pathways as crucial for sporulation. As rapamycin treatment blocked chlamydosporulation, a low basal Tor1 activity seems to be essential. In addition, TOR effector pathways play an important role, and loss of the NCR (nitrogen catabolite repression) gene regulators Gat1 and Gln3 reduced chlamydospore formation. A severe reduction was seen for a C. albicans gcn4Δ deletion strain, implicating a link between regulation of amino acid biosynthesis and chlamydospore development. On the other hand, deletion of the GTPase gene RAS1 and the adenylyl cyclase gene CYR1 caused a defect in chlamydospore formation that was mostly rescued by cAMP supplementation. Thus, cAMP-signaling is a second major pathway to control chlamydospore production. Finally, we confirmed light exposure to have a repressive effect on chlamydosporulation. However, permanent illumination only reduced, but not abolished chlamydospore production of C. albicans whereas C. dubliniensis sporulation was unaffected. In summary, we describe novel environmental factors which determine chlamydosporulation and propose a first model for the regulatory network of chlamydospore formation by different Candida species.
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Affiliation(s)
- Bettina Böttcher
- Department of Microbial Pathogenicity Mechanisms, Hans-Knöll-Institute Jena, Germany
| | - Christine Pöllath
- Department of Microbial Pathogenicity Mechanisms, Hans-Knöll-InstituteJena, Germany; Institute for Medical Microbiology, Jena University HospitalJena, Germany; Center for Sepsis Control and Care, Jena University HospitalJena, Germany
| | - Peter Staib
- Department of Research and Development, Kneipp GmbH Würzburg, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Hans-Knöll-InstituteJena, Germany; Center for Sepsis Control and Care, Jena University HospitalJena, Germany; Friedrich Schiller University JenaJena, Germany
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Hans-Knöll-Institute Jena, Germany
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19
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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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Navarathna DHMLP, Pathirana RU, Lionakis MS, Nickerson KW, Roberts DD. Candida albicans ISW2 Regulates Chlamydospore Suspensor Cell Formation and Virulence In Vivo in a Mouse Model of Disseminated Candidiasis. PLoS One 2016; 11:e0164449. [PMID: 27727302 PMCID: PMC5058487 DOI: 10.1371/journal.pone.0164449] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 09/26/2016] [Indexed: 01/05/2023] Open
Abstract
Formation of chlamydospores by Candida albicans was an established medical diagnostic test to confirm candidiasis before the molecular era. However, the functional role and pathological relevance of this in vitro morphological transition to pathogenesis in vivo remain unclear. We compared the physical properties of in vitro-induced chlamydospores with those of large C. albicans cells purified by density gradient centrifugation from Candida-infected mouse kidneys. The morphological and physical properties of these cells in kidneys of mice infected intravenously with wild type C. albicans confirmed that chlamydospores can form in infected kidneys. A previously reported chlamydospore-null Δisw2/Δisw2 mutant was used to investigate its role in virulence and chlamydospore induction. Virulence of the Δisw2/Δisw2 mutant strain was reduced 3.4-fold compared to wild type C. albicans or the ISW2 reconstituted strain. Altered host inflammatory reactions to the null mutant further indicate that ISW2 is a virulence factor in C. albicans. ISW2 deletion abolished chlamydospore formation within infected mouse kidneys, whereas the reconstituted strain restored chlamydospore formation in kidneys. Under chlamydospore inducing conditions in vitro, deletion of ISW2 significantly delayed chlamydospore formation, and those late induced chlamydospores lacked associated suspensor cells while attaching laterally to hyphae via novel spore-hypha septa. Our findings establish the induction of chlamydospores by C. albicans during mouse kidney colonization. Our results indicate that ISW2 is not strictly required for chlamydospores formation but is necessary for suspensor cell formation. The importance of ISW2 in chlamydospore morphogenesis and virulence may lead to additional insights into morphological differentiation and pathogenesis of C. albicans in the host microenvironment.
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Affiliation(s)
- Dhammika H. M. L. P. Navarathna
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ruvini U. Pathirana
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Michail S. Lionakis
- Fungal Pathogenesis Unit, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kenneth W. Nickerson
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - David D. Roberts
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
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Maiti P, Ghorai P, Ghosh S, Kamthan M, Tyagi RK, Datta A. Mapping of functional domains and characterization of the transcription factor Cph1 that mediate morphogenesis in Candida albicans. Fungal Genet Biol 2015; 83:45-57. [PMID: 26291891 DOI: 10.1016/j.fgb.2015.08.004] [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: 02/26/2015] [Revised: 08/09/2015] [Accepted: 08/15/2015] [Indexed: 11/26/2022]
Abstract
Cph1, a transcription factor of the Mitogen Activated Protein (MAP) kinase pathway, regulates morphogenesis in human fungal pathogen Candida albicans. Here, by following a systemic deletion approach, we have identified functional domains and motifs of Cph1 that are involved in transcription factor activity and cellular morphogenesis. We found that the N-terminal homeodomain is essential for the DNA binding activity; however, C-terminal domain and polyglutamine motif (PQ) are indispensable for the transcriptional activation function. Complementation analysis of the cph1Δ null mutant using various deletion derivatives revealed functional significance of the N- and C-terminal domains and PQ motif in filamentation process, chlamydospore formation and sensitivity to the cell wall interfering compounds. Genome-wide identification of the Cph1 binding site and quantitative RT-PCR transcript analysis in cph1Δ null mutant revealed that a number of genes which are associated with the filamentous growth, maintaining cell wall organization and mitochondrial function, and the genes of the pH response pathway are the transcriptional targets of Cph1. The data also suggest that Cph1 may function as a positive or negative regulator depending on the morphological state and physiological conditions. Moreover, differential expression of the upstream MAP kinase pathway genes in wild type and cph1Δ null mutant indicated the existence of a feedback regulation.
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Affiliation(s)
- Protiti Maiti
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India; National Institute of Plant Genome Research, New Delhi 110067, India
| | - Priyanka Ghorai
- National Institute of Plant Genome Research, New Delhi 110067, India
| | - Sumit Ghosh
- National Institute of Plant Genome Research, New Delhi 110067, India
| | - Mohan Kamthan
- National Institute of Plant Genome Research, New Delhi 110067, India
| | - Rakesh Kumar Tyagi
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India.
| | - Asis Datta
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India; National Institute of Plant Genome Research, New Delhi 110067, India.
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Abstract
Candida species are the most common causes of fungal infection. Approximately 90% of infections are caused by five species: Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, and Candida krusei. Three (C. albicans, C. tropicalis, and C. parapsilosis) belong to the CTG clade, in which the CTG codon is translated as serine and not leucine. C. albicans remains the most commonly isolated but is decreasing relative to the other species. The increasing incidence of C. glabrata is related to its reduced susceptibility to azole drugs. Genome analysis suggests that virulence in the CTG clade is associated with expansion of gene families, particularly of cell wall genes. Similar independent processes took place in the C. glabrata species group. Gene loss and expansion in an ancestor of C. glabrata may have resulted in preadaptations that enabled pathogenicity.
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Affiliation(s)
- Siobhán A Turner
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Geraldine Butler
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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